F1

MDRO and CDI Module

Multidrug-Resistant Organism & Clostridium difficile Infection (MDRO/CDI) Module
Background: Methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus
spp. (VRE) and certain gram-negative bacilli have increased in prevalence in U.S. hospitals over the last
three decades, and have important implications for patient safety. A primary reason for concern about these
multidrug-resistant organisms (MDROs) is that options for treating patients with these infections are often
extremely limited, and MDRO infections are associated with increased lengths of stay, costs, and mortality.
Many of these traits have also been observed for Clostridium difficile infection (CDI). The Healthcare
Infection Control Practices Advisory Committee (HICPAC) approved guidelines for the control of
MDROs.1 These are available at (http://www.cdc.gov/ncidod/dhqp/pdf/ar/mdroGuideline2006.pdf). The
MDRO and CDI module of the NHSN can provide a tool to assist facilities in meeting some of the criteria
outlined in the guidelines. In addition, many of the metrics used in this module are consistent with
“Recommendations for Metrics for Multidrug-Resistant Organisms in Healthcare Settings: SHEA/HICPAC
Position Paper.”2
Clostridium difficile is responsible for a spectrum of C. difficile infections (CDI) [originally referred to as C.
difficile-associated disease or CDAD], including uncomplicated diarrhea, pseudomembranous colitis, and
toxic megacolon which can, in some instances, lead to sepsis and even death. Current CDC definitions for
healthcare-associated infections (HAIs), while adequate for the site of infection, do not take into account the
special characteristics of disease caused by C. difficile. Although CDI represents a subset of gastroenteritis
and gastrointestinal tract infections, specific standard definitions for CDI 3 should be incorporated to obtain
a more complete understanding of how C. difficile is being transmitted in a healthcare facility. Please note
the term CDI is replacing CDAD. Both terms represent the same illness and are used interchangeably. We
are transitioning this module to the newer terminology.
As outlined in the HICPAC guideline1, these MDRO and C. difficile pathogens may require specialized
monitoring to evaluate if intensified infection control efforts are required to reduce the occurrence of these
organisms and related infections. The goal of this module is to provide a mechanism for facilities to report
and analyze these data that will inform infection control staff of the impact of targeted prevention efforts.
This module contains two options, one focused on MDROs and the second on CDI. Reporting options are
summarized in Table 1, below.
Table 1. Required and Optional Reporting Choices for MDRO and CDI Module
Reporting Choices
MRSA or
VRE
Klebsiella spp.
MRSA/MSSA
(CephR or CRE),
E. coli (CRE),
Acinetobacter spp. (MDR)
Required
Method
Method
Method
Infection Surveillance
(*Location Specific for
A, B
A, B
A, B
≥ 3 months)
Choose ≥ 1 organism
OR

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C. difficile

Method
±

A, B

MDRO and CDI Module

Proxy Infection
Measures
§
Laboratory-Identified
(LabID) Event
(*Location Specific for
≥ 3 consecutive
months)
Choose ≥ 1 organism
Optional
Prevention Process
Measures Options:
Hand Hygiene
Adherence
Gown and Gloves
Use Adherence
Active Surveillance
Testing (AST)
Adherence
AST Outcome
Measures
Incident and
Prevalent Cases using
AST

±

A, B, C, D

A, B, C, D

B,C, D

A, B, C

Method

Method

Method

Method

B

B

B

B

B

B

B

B

B

B

N/A

N/A

B

B

N/A

N/A

*Location: Patient care area selected for monitoring and reported in Monthly Reporting Plan.
N/A – not available or contraindicated
±

No surveillance for CDI will be performed in Neonatal Intensive Care Units (NICU), Well Baby Nurseries,
or Well Baby Clinics. And, if conducting facility-wide monitoring (Method C) the denominator counts
(admissions, patient-days, encounters) for these locations must be removed.
§

LabID Events can be reported Overall facility-wide for all inpatient areas and/or Overall facility-wide for
all outpatient areas. Additionally events can be reported Facility-wide by location to cover all inpatient
areas or by Selected locations.
Method (minimum requirement is 3 months for Infection Surveillance or 3 consecutive months for LabID
Event reporting using one of the methods below):
A – Facility-wide by location. Requires the most effort but provides the most detail for local and national
statistical data.
B – Selected locations within the facility (1 or more). Acceptable method, ideal for use during targeted
prevention programs.

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C – Overall facility-wide. Acceptable method, ideal for CDI or MDRO infrequently encountered, or smaller
hospitals. Options include Overall Facility-wide Inpatient (FacWideIN) to cover all inpatient locations or
Overall Facility-wide Outpatient (FacWideOUT) to cover all outpatient locations.
D – Overall facility-wide: Blood Specimens Only. Available for MDROs only (no CDI). Targets the most
invasive events. Options include Overall Facility-wide Inpatient (FacWideIN) to cover all inpatient
locations or Overall Facility-wide Outpatient (FacWideOUT) to cover all outpatient locations.
I. MDRO Option
Methodology: Facilities may choose to monitor one or more of the following MDROs: MRSA, MRSA
and MSSA, VRE, CephR- Klebsiella spp., CRE-Klebsiella spp., CRE-E. coli, and multidrug-resistant
Acinetobacter spp. (See definitions in Section A, Option 1). For S. aureus, both the resistant (MRSA) and
the susceptible (MSSA) phenotypes can be tracked to provide concurrent measures of the susceptible
pathogens as a comparison to those of the resistant pathogens in a setting of active prevention efforts
targeted at the resistant pathogen.
Participants must choose 1 or both of the 2 required reporting options described below and then may also
choose to participate in either or both of the 2 additional optional monitoring methods described below (see
Table 1):
Required Reporting Options:
• MDRO infection surveillance, i.e., for each patient care area selected, surveillance for all NHSN-defined
healthcare-associated infections caused by at least one MDRO.
AND/OR
• LabID Event reporting of proxy infection measures of MDRO healthcare acquisition, exposure burden,
and infection burden by using primarily laboratory data. Laboratory testing results can be used without
clinical evaluation of the patient, allowing for a much less labor-intensive means to track MDROs.
These can be monitored facility-wide for inpatient areas – FacWideIN or facility-wide for outpatient
areas – FacWideOUT (Method C – all specimens or Method D – blood specimens only) or for specific
locations (Method A or B with unique denominator data), allowing for both location-specific and
facility-wide measures.
Additional Optional Monitoring Methods:
• Prevention process measures that allow facilities to systematically collect data on hand hygiene and
gown and gloves use adherence, and for those conducting active surveillance testing (AST), adherence
to obtaining AST.
• AST outcome measures that can be reported if AST is performed, providing incidence and prevalence
rates for selected MDROs.
The data collections in the MDRO Option will enable participating facilities and CDC to calculate several
measures, depending on which reporting methods the facility chooses to follow (see Table 2 at the end of
this chapter). NHSN forms should be used to collect all required data, using the definitions of each data
field as outlined in this protocol and in the “Instructions for Completion of MDRO/CDI Forms”. When
denominator data are available from electronic databases, these sources may be used as long as the counts
are not substantially different (+ or – 5%) from manually collected counts.

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Active, patient-based, prospective surveillance of the chosen MDRO infections by a trained infection
preventionist (IP) is required for MDRO infection surveillance. This means that the IP shall seek to confirm
and classify infections caused by the MDRO(s) chosen for monitoring during a patient’s stay in at least one
patient care location during the surveillance period. Some process measures require direct observation as
described in Section IB. Personnel other than the IP may be trained to perform these observations and
collect the required data elements.
A. Required Reporting
Option 1. MDRO Infection Surveillance – (MRSA, MRSA/MSSA, VRE, CephR-Klebsiella spp., CREKlebsiella spp., CRE-E. coli spp., and MDR-Acinetobacter spp.).
Settings: Infection Surveillance can occur in any inpatient location where such infections may be identified
and where denominator data can be collected, which may include critical/intensive care units (ICU),
specialty care areas (SCA), neonatal units, stepdown units, wards, and long term care units.
Requirements: Surveillance for all types of NHSN-defined healthcare-associated infections (HAIs) of the
MDRO selected for monitoring in at least one location in the healthcare facility for at least 3 months in a
calendar year as indicated in the Patient Safety Monthly Reporting Plan (CDC 57.106).
Definitions: MDROs included in this module are defined below. Refer to Chapter 17 for infection site
criteria. Refer to Key Terms for assistance with variable definitions.
MRSA: Includes S. aureus cultured from any specimen that tests oxacillin-resistant, cefoxitin-resistant, or
methicillin-resistant by standard susceptibility testing methods, or by a positive result from molecular
testing for mecA and PBP2a; these methods may also include positive results of specimens tested by any
other FDA approved PCR test for MRSA.
MSSA: S. aureus cultured from any specimen testing intermediate or susceptible to oxacillin, cefoxitin, or
methicillin by standard susceptibility testing methods, or by a negative result from molecular testing for
mecA and PBP2a.
VRE: Any Enterococcus spp. (regardless of whether identified to the species level), that is resistant to
vancomycin.
CephR-Klebsiella: Any Klebsiella spp. testing non-susceptible (i.e., resistant or intermediate) to
ceftazidime, cefotaxime, ceftriaxone, or cefepime.
CRE-Ecoli: Any E. coli testing non-susceptible (i.e., resistant or intermediate) to imipenem, meropenem, or
doripenem.
CRE-Klebsiella: Any Klebsiella spp. testing non-susceptible (i.e., resistant or intermediate) to imipenem,
meropenem, or doripenem.
MDR-Acinetobacter: Any Acinetobacter spp. testing non-susceptible (i.e., resistant or intermediate) to at
least one agent in at least 3 antimicrobial classes of the following 6 antimicrobial classes:

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β-lactam/β-lactam
β-lactamase inhibitor
combination
Piperacillin
Piperacillin/tazobactam
Cephalosporins
Cefepime
Ceftazidime

Aminoglycosides

Carbapenems

Fluoroquinolones

Amikacin
Gentamicin
Tobramycin

Imipenem
Meropenem
Doripenem

Ciprofloxacin
Levofloxacin

Sulbactam
Ampicillin/sulbactam

Location of Attribution and Transfer Rule applies – See Key Terms.
Numerator Data: Number of healthcare-associated infections (HAIs), by MDRO type. Infections are
reported on the appropriate NHSN forms: Primary Bloodstream Infection, Pneumonia, Urinary Tract
Infection, Surgical Site Infection, or MDRO or CDI Infection Event (CDC 57.108, 57.111, 57.114, 57.120,
and 57.126, respectively.) (See Tables of Instructions, Tables 2, 2a, 4, 5, 12, and 19, respectively, for
completion instructions.)
Denominator Data: Number of patient days. Patient Days are reported using the MDRO and CDI
Prevention Process and Outcome Measures Monthly Monitoring form (CDC 57.127). (See Tables of
Instructions, Table 21, for completion instructions.)
Data Analysis: Data are stratified by time (e.g., month, quarter, etc.) and patient care location.
MDRO Infection Incidence Rate = Number of HAIs by MDRO type/ Number of patient days X 1000
Option 2. Laboratory-Identified (LabID) Event
Introduction: To calculate proxy measures of MDRO infections, exposures, and healthcare acquisition
facilities may choose to monitor laboratory-identified MDRO events. This method allows the facility to rely
almost exclusively on easily obtained data from the clinical microbiology laboratory. However, some data
elements, such as date admitted to the patient care location and facility may require other data sources.
Please be aware that the LabID Event reporting is ONLY for collecting and tracking positive cultures that
are taken for "clinical" purposes (i.e., for diagnosis and treatment), which means that NO Active
Surveillance Culture/Testing (ASC/AST) results are to be included in this reporting of individual
results. Do NOT enter surveillance nasal swabs or other surveillance cultures as reports of LabID Events.
AST tracking should be recorded under Process & Outcome Measures.
Laboratory and admission data elements can be used to calculate four distinct proxy measures including:
admission prevalence rate and overall patient prevalence rate based on clinical testing (measures of
exposure burden), MDRO bloodstream infection incidence rate (measure of infection burden), and overall
MDRO infection/colonization incidence rate (measure of healthcare acquisition). MDRO positive
laboratory results can be reported for one or more organisms. For S. aureus, both the resistant (MRSA) and
the susceptible (MSSA) phenotypes can be tracked to provide concurrent measures of the susceptible

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pathogens as a comparison to those of the resistant pathogens in a setting of active prevention efforts
targeted at the resistant pathogen.
Settings: MDRO LabID Event reporting can occur in any location: inpatient or outpatient.
Requirements: Facilities choose at least 1 of 4 reporting methods: (A) Facility-wide by location: report
location-specific data for the entire facility, requiring separate denominator submissions for each location;
(B) Selected locations: report location-specific data for only selected locations; and (C or D) Overall
facility-wide (Options include Overall Facility-wide Inpatient for all inpatient locations, and/or Overall
Facility-wide Outpatient for all outpatient locations.) report only one denominator for the entire facility and
either all specimens(Method C) or blood specimens only (Method D) (see protocol Table 1). Facilities must
indicate each reporting choice chosen for the calendar month as indicated in the Patient Safety Monthly
Reporting Plan (CDC 57.106). Facilities can report using Methods A & C or D, B & C or D, or A, B, C, or
D (but not A & B). Surveillance for positive laboratory results must be reported for 3 consecutive months to
provide meaningful measures.
For each MDRO being monitored, all MDRO test results are evaluated using the algorithm in Figure 1 to
determine reportable LabID events for each calendar month, for each facility location as determined by the
reporting method chosen. All first MDRO isolates (chronologically) per patient, per month, per location are
reported as a LabID event regardless of specimen source (EXCLUDES tests related to active surveillance
testing); if a duplicate MDRO isolate is from blood, it is reported as a LabID event only if it represents a
unique blood source (i.e., no prior isolation of the MDRO in blood from the same patient and location in ≤ 2
weeks, even across calendar months) (Figure 1). As a general rule, at a maximum, there should be no more
than 2 blood isolates reported,(which would be very rare), and 1 first MDRO isolate (specimen other than
blood) reported on any patient during a calendar month for each location chosen for reporting. If a blood
isolate is entered as the first specimen of the month, then no non-blood specimens can be entered that month
for that patient and location. Report a single LabID Event per form.
Definitions:
MDRO Isolate: Any specimen obtained for clinical decision making testing positive for a MDRO (as
defined above). (EXCLUDES tests related to active surveillance testing)
Duplicate MDRO Isolate: Any MDRO isolate from the same patient and location after an initial isolation of
the specific MDRO during a calendar month, regardless of specimen source except unique blood source
(Figure 1).
Laboratory-Identified (LabID) Event: All non-duplicate MDRO isolates from any specimen source and
unique blood source MDRO isolates, including specimens collected during an Emergency Department or
other outpatient clinic visit, if collected the same day as patient admission (EXCLUDES tests related to
active surveillance testing).
Unique Blood Source: A MDRO isolate from blood in a patient with no prior positive blood culture for the
same MDRO and location in ≤ 2 weeks, even across calendar months (Figure 1). There should be a full 14

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days with no positive blood culture result from the laboratory for the patient, MDRO, and location before
another Blood LabID Event is entered into NHSN for the patient, MDRO, and location.
Numerator Data: Data will be reported using the Laboratory-identified MDRO or CDI Event form (CDC
57.128). (See Tables of Instructions, Table 20, for completion instructions.)
Denominator Data: Patient days, admissions, (for inpatient locations) and encounters (for ER and
outpatient locations) are reported using the MDRO and CDI Prevention Process and Outcome Measures
Monthly Monitoring form (CDC 57.127). (See Tables of Instructions, Table 21, for completion
instructions.) When determining a patient’s admission dates to both the facility and specific inpatient
location, the NHSN user must take into account all such days, including any days spent in an inpatient
location as an “observation” patient before being officially admitted as an inpatient to the facility, as these
days contribute to exposure risk. Therefore, all such days are included in the counts of admissions and
patient days for the facility and specific location, and facility and admission dates must be moved back to
the first day spent in the inpatient location. For further information on counting patient days and
admissions, go to NHSN website>Resource Library>NHSN Guides>Determining Patient Days for
Summary Data Collection: Observation vs. Inpatients.
Data Analysis: Based on data provided on the LabID Event form, each event can be categorized by NHSN
to populate different measures. Of note, NHSN will categorize LabID Events as healthcare facility-onset vs.
community-onset to ensure that all healthcare facility-onset cases have been hospitalized at least a full 48
hours before specimen collection. Considering: 1) variable times of day that admissions occur and 2) the
absence of clinical data to confirm if cultures represent infection incubating at the time of admission, this is
operationalized by classifying positive cultures obtained on day 1 (admission date), day 2, and day 3 of
admission as community-onset (CO) LabID Events and positive cultures obtained on or after day 4 as
healthcare facility-onset (HO) LabID Events.
The following categorizations and prevalence and incidence calculations are built into the analysis
capabilities of NHSN, and are based on timing of admission and specimen collection, and location where
specimen was collected. Descriptions are provided to explain how the categories and metrics are defined in
NHSN.
Categorizing MDRO LabID Events – Based on Date Admitted to Facility and Date Specimen
Collected:
Community-Onset (CO): LabID Event specimen collected as an outpatient or an inpatient ≤ 3 days after
admission to the facility (i.e., days 1, 2, or 3 of admission).
Healthcare Facility-Onset (HO): LabID Event specimen collected > 3 days after admission to the facility
(i.e., on or after day 4).

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Proxy Measures for Exposure Burden of MDROs – All specimens:
Inpatient Reporting:
Admission Prevalence Rate = Number of 1st LabID Events per patient per month identified ≤ 3 days after
admission to the location (if monitoring by inpatient location), or the facility (if monitoring by overall
facility-wide inpatient=FacWideIN) / Number of patient admissions to the location or facility x 100
Location Percent Admission Prevalence that is Community-Onset = Number of Admission Prevalent LabID
Events to a location that are CO / Total number Admission Prevalent LabID Events x 100
Location Percent Admission Prevalence that is Healthcare Facility-Onset = Number of Admission Prevalent
LabID Events to a location that are HO / Total number of Admission Prevalent LabID Events x 100
Overall Patient Prevalence Rate = Number of 1st LabID Events per patient per month regardless of time
spent in location (i.e., prevalent + incident, if monitoring by inpatient location), or facility (i.e., CO + HO, if
monitoring by overall facility-wide inpatient=FacWideIN) / Number of patient admissions to the location or
facility x 100
Outpatient Reporting:
Outpatient Prevalence Rate = Number of 1st LabID Events per patient per month for the location (if
monitoring by outpatient location), or the facility (if monitoring by overall facility-wide outpatient =
FacWideOUT) / Number of patient encounters for the location or facility x 100
Proxy Measures for MDRO Bloodstream Infection: (Calculated when monitoring either All specimens or
Blood specimens only.) Remember, the Blood specimens only option can only be used at the FacWideIN
and FacWideOUT levels.
Inpatient Reporting:
MDRO Bloodstream Infection Admission Prevalence Rate = Number of all unique blood source LabID
Events per patient per month identified ≤ 3 days after admission to the location (if monitoring by inpatient
location), or facility (if monitoring by overall facility-wide inpatient=FacWideIN)/ Number of patient
admissions to the location or facility x 100
MDRO Bloodstream Infection Incidence or Incidence Density Rate = Number of all unique blood source
LabID Events per patient per month identified > 3 days after admission to the location (if monitoring by
inpatient location), or facility (if monitoring by overall facility-wide inpatient=FacWideIN) / Number of
patient admissions to the location or facility x 100 or Number of patient days for the location or facility x
1,000
MDRO Bloodstream Infection Overall Patient Prevalence Rate = Number of 1st Blood LabID Events per
patient per month regardless of time spent in location (i.e., prevalent + incident, if monitoring by inpatient
location), or facility (i.e., CO + HO, if monitoring by overall facility-wide inpatient=FacWideIN) / Number
of patient admissions to the location or facility x 100

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MDRO and CDI Module

Outpatient Reporting:
MDRO Bloodstream Infection Outpatient Prevalence Rate = Number of all unique blood source LabID
Events per patient per month for the location (if monitoring by outpatient location), or the facility (if
monitoring by overall facility-wide outpatient=FacWideOUT) / Number of patient encounters for the
location or facility x 100
Proxy Measures for MDRO Healthcare Acquisition:
Overall MDRO Infection/Colonization Incidence Rate = Number of 1st LabID Events per patient per month
among those with no documented prior evidence of previous infection or colonization with this specific
organism type from a previously reported LabID Event, and identified > 3 days after admission to the
location (if monitoring by inpatient location), or facility (if monitoring by overall facility-wide
inpatient=FacWideIN) / Number of patient admissions to the location or facility x 100
Overall MDRO Infection/Colonization Incidence Density Rate = Number of 1st LabID Events per patient
per month among those with no documented prior evidence of previous infection or colonization with this
specific organism type from a previously reported LabID Event, and identified > 3 days after admission to
the location (if monitoring by inpatient location), or facility (if monitoring by overall facility-wide
inpatient=FacWideIN) / Number of patient days for the location or facility x 1,000
B. Optional Reporting
1. Prevention Process Measures Surveillance
a. Monitoring Adherence to Hand Hygiene
Introduction: This option will allow facilities to monitor adherence to hand hygiene after a healthcare
worker (HCW) has contact with a patient or inanimate objects in the immediate vicinity of the patient.
Research studies have reported data suggesting that improved after-contact hand hygiene is associated with
reduced MDRO transmission. While there are multiple opportunities for hand hygiene during patient care,
for the purpose of this option, only hand hygiene after contact with a patient or inanimate objects in the
immediate vicinity of the patient will be observed and reported. (http://www.cdc.gov/handhygiene/)
Settings: Surveillance will occur in any location: inpatient or outpatient.
Requirements: Surveillance for adherence to hand hygiene in at least one location in the healthcare
institution for at least one calendar month as indicated in the Patient Safety Monthly Reporting Plan (CDC
57.106). Ideally, this should be done in patient care locations also selected for Infection Surveillance or
LabID Event reporting.
In participating patient care locations, perform at least 30 different unannounced observations after
contact with patients for as many individual HCWs as possible. For example, try to observe all types of
HCWs performing a variety of patient care tasks during the course of the month, not only nurses, or not only
during catheter or wound care. No personal identifiers will be collected or reported.

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MDRO and CDI Module

Definitions:
Antiseptic handwash: Washing hands with water and soap or other detergents containing an antiseptic
agent.
Antiseptic hand rub: Applying an antiseptic hand-rub product to all surfaces of the hands to reduce the
number of microorganisms present.
Hand hygiene: A general term that applies to either: handwashing, antiseptic hand wash, antiseptic hand
rub, or surgical hand antisepsis.
Handwashing: Washing hands with plain (i.e., non-antimicrobial) soap and water.
Numerator: Hand Hygiene Performed = Total number of observed contacts during which a HCW touched
either the patient or inanimate objects in the immediate vicinity of the patient and appropriate hand hygiene
was performed.
Denominator: Hand Hygiene Indicated = Total number of observed contacts during which a HCW touched
either the patient or inanimate objects in the immediate vicinity of the patient and therefore, appropriate
hand hygiene was indicated.
Hand hygiene process measure data are reported using the MDRO and CDI Prevention Process and
Outcome Measures Monthly Monitoring form (CDC 57. 127). (See Tables of Instructions, Table 21, for
completion instructions.)
Data Analysis: Data are stratified by time (e.g., month, quarter, etc.) and patient care location.
Hand Hygiene Percent Adherence = Number of contacts for which hand hygiene was performed / Number
of contacts for which hand hygiene was indicated X 100
b. Monitoring Adherence to Gown and Gloves Use as Part of Contact Precautions
Introduction: This option will allow facilities to monitor adherence to gown and gloves use when a HCW
has contact with a patient or inanimate objects in the immediate vicinity of the patient, when that patient is
on Transmission-based Contact Precautions. While numerous aspects of adherence to Contact Precautions
could be monitored, this surveillance option is only focused on the use of gown and gloves.
(http://www.cdc.gov/ncidod/dhqp/gl_isolation_contact.html)
Settings: Surveillance can occur in any of 4 types of inpatient locations: (1) intensive care units (ICU), (2)
specialty care areas (includes hematology/oncology wards, bone marrow transplant units, inpatient dialysis
units, solid organ transplant units, long term acute care areas), (3) neonatal intensive care units (NICU), and
(4) any other inpatient care location in the institution (e.g., surgical wards).
Requirements: Surveillance for adherence to gown and gloves use in at least one location in the healthcare
institution for at least 1 calendar month as indicated in the Patient Safety Monthly Reporting Plan (CDC

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MDRO and CDI Module

57.106). Ideally, this should be done in patient care locations also selected for Infection Surveillance or
LabID Event reporting.
Among patients on Transmission-based Contact Precautions in participating patient care locations,
perform at least 30 unannounced observations. A total of thirty different contacts must be observed monthly
among HCWs of varied occupation types. For example, try to observe all types of HCWs performing a
variety of patient care tasks during the course of the month, not only nurses, or not only during catheter or
wound care. Both gown and gloves must be donned prior to contact for compliance. No personal identifiers
will be collected or reported.
Definitions:
Gown and gloves use: In the context of Transmission-based Contact Precautions, the donning of both a
gown and gloves prior to contact with a patient or inanimate objects in the immediate vicinity of the patient.
Both a gown and gloves must be donned prior to contact for compliance.
Numerator: Gown and Gloves Used = Total number of observed contacts between a HCW and a patient or
inanimate objects in the immediate vicinity of the patient for which gown and gloves had been donned prior
to the contact.
Denominator: Gown and Gloves Indicated = Total number of observed contacts between a HCW and a
patient on Transmission-based Contact Precautions or inanimate objects in the immediate vicinity of the
patient and therefore, gown and gloves were indicated.
Gown and gloves use process measure data are reported using the MDRO and CDI Prevention Process and
Outcome Measures Monthly Monitoring form (CDC 57.127). (See Tables of Instructions, Table 21, for
completion instructions.)
Data Analysis: Data are stratified by time (e.g., month, quarter, etc.) and patient care location.
Gown and Glove Use Percent Adherence = Number of contacts for which gown and gloves were used /
Number of contacts for which gown and gloves were indicated X 100
c. Monitoring Adherence to Active Surveillance Testing
Introduction: This option will allow facilities to monitor adherence to active surveillance testing (AST) of
MRSA and/or VRE, using culturing or other methods.
Settings: Surveillance will occur in any of 4 types of inpatient locations: (1) intensive care units (ICU), (2)
specialty care areas (includes hematology/oncology wards, bone marrow transplant units, inpatient dialysis
units, solid organ transplant units, long term acute care areas), (3) neonatal intensive care units (NICU), and
(4) any other inpatient care location in the institution (e.g., surgical wards).
Requirements: Surveillance of AST adherence in at least one location in the healthcare facility for at least
one calendar month as indicated in the Patient Safety Monthly Reporting Plan (CDC 57.106). A facility may
choose to report AST for MRSA and/or VRE in one or multiple patient care locations, as the facility deems

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appropriate. Ideally, this should be done in patient care locations also selected for Infection Surveillance or
LabID Event reporting. To improve standardization of applying timing rules relating to when AST
specimens are obtained, classify admission specimens as those obtained on day 1 (admission date), day 2, or
day 3 (i.e., ≤ 3 days). Classify discharge/transfer AST specimens as those collected on or after day 4 (i.e., >
3 days).
Definitions:
AST Eligible Patients: Choose one of two methods for identifying patients that are eligible for AST:
All = All patients in the selected patient care area regardless of history of MRSA or VRE infection or
colonization.
OR
NHx = All patients in the selected patient care area who have NO documented positive MRSA or VRE
infection or colonization during the previous 12 months (as ascertained by either a facility’s laboratory
records or information provided by referring facilities); and no evidence of MRSA or VRE during stay in
the patient care location (i.e., they are not in Contact Precautions).
Timing of AST: Choose one of two methods for reporting the timing of AST:
Adm = Specimens for AST obtained ≤ 3 days after admission,
OR
Both = Specimens for AST obtained ≤ 3 days after admission and, for patients’ stays of > 3 days, at the
time of discharge/transfer. Discharge/transfer AST should include all discharges (including discharges from
the facility or to other wards or deaths) and can include the most recent weekly AST if performed > 3 days
after admission to the patient care location. Discharge/transfer AST should not be performed on patients
who tested positive on AST admission.
Numerator and Denominator Data: Use the MDRO and CDI Prevention Process and Outcome Measures
Monthly Monitoring form (CDC 57.127) to indicate: 1) AST was performed during the month for MRSA
and/or VRE, 2) AST-eligible patients, and 3) the timing of AST. No personal identifiers will be collected or
reported. (See Tables of Instructions, Table 21, for completion instructions.)
Numerator: For each month during which AST is performed:
Admission AST Performed = Number of patients eligible for admission AST who had a specimen obtained
for testing ≤ 3 days after admission,
AND/OR
Discharge/Transfer AST Performed = For patients’ stays > 3 days, the number of discharged or transferred
patients eligible for AST who had a specimen obtained for testing prior to discharge, not including the
admission AST.
Denominator: For each month during which AST is performed:
Admission AST Eligible = Number of patients eligible for admission AST (All or NHx),
AND/OR
Discharge/Transfer AST Eligible = Number of patients eligible for discharge/transfer AST (All or NHx)
AND in the facility location > 3 days AND negative if tested on admission.

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MDRO and CDI Module

Data Analysis: Data are stratified by patient care location and time (e.g., month, quarter, etc.), according to
AST-eligible patients monitored and the timing of AST.
Admission AST Percent Adherence = Number of patients with admission AST Performed / Number of
patients admission AST eligible X 100
Discharge/transfer AST Percent Adherence = Number of patients with discharge/transfer AST performed /
Number of patients discharge/transfer AST eligible X 100
2. Active Surveillance Testing Outcome Measures
Introduction: This option will allow facilities to use the results of AST to monitor the prevalent and
incident rates of MRSA and/or VRE colonization or infection. This information will assist facilities in
assessing the impact of intervention programs on MRSA or VRE transmission.
Settings: Surveillance will occur in any of 4 types of inpatient locations: (1) intensive care units (ICU), (2)
specialty care areas (includes hematology/oncology wards, bone marrow transplant units, inpatient dialysis
units, solid organ transplant units, long term acute care areas), (3) neonatal intensive care units (NICU), and
(4) any other inpatient care location in the institution (e.g., surgical wards).
Requirements: Surveillance for prevalent and/or incident MRSA or VRE cases in at least one location in
the healthcare facility for at least one calendar month as indicated in the Patient Safety Monthly Reporting
Plan (CDC 57.106). This can be done ONLY in locations where AST adherence is being performed. A
minimum AST adherence level will be required for the system to calculate prevalence and incidence. A
facility may choose to report AST for MRSA and/or VRE in one or multiple patient care locations, as the
facility deems appropriate. Ideally, this should be done in patient care locations also selected for Infection
Surveillance or LabID Event reporting. To improve standardization of applying timing rules relating to
when AST specimens are obtained, classify admission specimens as those obtained on day 1 (admission
date), day 2, or day 3 (i.e., ≤ 3 days). Classify discharge/transfer AST specimens as those collected on or
after day 4 (i.e., > 3 days). Only the first specimen positive for MRSA or VRE from a given patient in the
patient care location is counted, whether obtained for AST or as part of clinical care. If an Admission AST
specimen is not collected from an eligible patient, assume the patient has no MRSA or VRE colonization.
Definitions:
AST Admission Prevalent case:
Known Positive = A patient with documentation on admission of MRSA or VRE colonization or infection
in the previous 12 months (i.e., patient is known to be colonized or infected as ascertained by either a
facility’s laboratory records or information provided by referring facilities). (All MRSA or VRE colonized
patients currently in the ICU during the month of surveillance should be considered “Known Positive”),
OR
Admission AST or Clinical Positive = A patient with MRSA or VRE isolated from a specimen collected for
AST ≤ 3 days after admission or from clinical specimen obtained ≤ 3 days after admission (i.e., MRSA or
VRE cannot be attributed to this patient care location).

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MDRO and CDI Module

AST Incident case: A patient with a stay > 3 days:
With no documentation on admission of MRSA or VRE colonization or infection during the previous 12
months (as ascertained either by the facility’s laboratory records or information provided by referring
facilities); including admission AST or clinical culture obtained ≤ 3 days after admission (i.e., patient
without positive specimen),
AND
With MRSA or VRE isolated from a specimen collected for AST or clinical reasons > 3 days after
admission to the patient care location or at the time of discharge/transfer from the patient care location
(including discharges from the facility or to other wards or deaths).
MRSA colonization: Carriage of MRSA without evidence of infection (e.g., nasal swab test positive for
MRSA, without signs or symptoms of infection).
AST Eligible Patients: Choose one of two methods for identifying patients eligible for AST:
All = All patients in the selected patient care area regardless of history of MRSA or VRE infection or
colonization,
OR
NHx = All patients in the selected patient care area who have NO documented positive MRSA or VRE
infection or colonization during the previous 12 months (as ascertained either by the facility’s laboratory
records or information provided by referring facilities); and no evidence of MRSA or VRE during stay in
the patient care location (i.e., they are not in Contact Precautions).
Timing of AST: Choose one of two methods for reporting the timing of AST:
Adm = Specimens for AST obtained ≤ 3 days after admission,
OR
Both = Specimens for AST obtained ≤ 3 days after admission and, for patients’ stays of > 3 days, at the time
of discharge/transfer. Discharge/transfer AST should include all discharges (including discharges from the
facility or to other wards or deaths) and can include the most recent weekly AST if performed > 3 days after
admission to the patient care location. Discharge/transfer AST should not be performed on patients who
tested positive on AST admission.
Numerator and Denominator Data: Use the MDRO and CDI Prevention Process and Outcome Measures
Monthly Monitoring form (CDC 57.127) to indicate: 1) AST outcomes monitoring and adherence was
performed during the month for MRSA and/or VRE, 2) AST eligible patients, and 3) the timing of AST. No
personal identifiers will be collected or reported. (See Tables of Instructions Table 21, for completion
instructions.)
If only admission AST is performed, only prevalent cases of MRSA or VRE can be detected in that patient
care location. If both admission and discharge/transfer AST are performed, both prevalent and incident
cases can be detected. No personal identifiers will be collected or reported.

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MDRO and CDI Module

Admission Prevalent Case:
Numerator Sources:
• Known Positive
• Admission AST or Clinical Positive = Cases ≤ 3 days after admission
Denominator: Total number of admissions
Incident Case:
Numerator: Discharge/transfer AST or Clinical Positive = Cases > 3 days after admission
Denominator: Total number of patient days
NOTE: For research purposes calculating patient-days at risk (i.e., excluding patient-days in which patients
were known to be MRSA or VRE colonized or infected) may be a preferable denominator, but for
surveillance purposes and ease of aggregating, total number of patient days is required for this module.
Data Analysis: Data are stratified by patient care location and time (e.g., month, quarter, etc.) according to
the eligible patients monitored and timing of AST.
AST Admission Prevalence rate =
For Eligible patients = All:
Number of admission AST or clinical positive / Number of admissions X 100
For Eligible patients = NHx:
Number of admission AST or clinical positive + Number of known positive / Number of admissions X 100
AST Incidence rate = Number of discharge/transfer AST or clinical positive / Number of patient days X
1000

II. Clostridium difficile Infection (CDI) Option
Methodology: The CDI Option also allows for a choice between two required reporting options and
additional optional monitoring methods. As with MDRO monitoring, if a facility chooses to monitor C.
difficile it must use at least one of the following reporting options: Infection Surveillance and/or Laboratoryidentified (LabID) Event reporting. Process measure reporting is optional (but available only for hand
hygiene and gown and gloves use – no AST). See Table 1.
C. difficile Infection (CDI) Surveillance, reporting on all NHSN-defined healthcare-associated CDIs from at
least one patient care area, is one surveillance option for C. difficile (i.e., part of your facility’s Monthly
Reporting Plan). These data will enhance the ability of NHSN to aggregate national data on CDIs. This
method requires active, patient-based, prospective surveillance of healthcare-associated C. difficile
infections by a trained infection preventionist (IP). This means that the IP shall seek to confirm and classify

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MDRO and CDI Module

infections caused by C. difficile during a patient’s stay in at least one patient care location during the
surveillance period.
Laboratory-identified (LabID) Events reporting is the second surveillance option and allows laboratory
testing data to be used without clinical evaluation of the patient, allowing for a much less labor intensive
method to track C. difficile. These provide proxy measures of C. difficile healthcare acquisition, exposure
burden, and infection burden based solely on laboratory data and limited admission date data. Reporting of
LabID Events for the entire facility (Method C – All specimens) (i.e., Overall facility-wide inpatient –
FacWideIN and Overall facility-wide outpatient – FacWideOUT) can provide easily obtainable and valuable
information for the facility. LabID Events can also be monitored for specific locations with unique
denominator data required from each specific location (i.e., Facility-wide by location – Method A or
Selected locations – Method B). This allows for both location-specific and facility-wide measures.
Process measure monitoring includes optional reporting aspects that allow facilities to systematically report
information on C. difficile prevention process measures for hand hygiene and gown and gloves use. These
measures require direct observation and are described in Sections I.B.1.a. and I.B.1.b. (MDRO Option Prevention Process Measures). Personnel other than the IP may be trained to perform these observations
and the collection of data elements.
Use NHSN forms to collect all required data, using the definitions of each data field as indicated in the
Tables of Instructions (Tables, 19, 20, and 21). When denominator data are available from electronic
databases, these sources may be used as long as the counts are not substantially different (+ or – 5%) from
manually collected counts.
A. Required Reporting
Option 1. Clostridium difficile Infection Surveillance
Settings: Infection Surveillance will occur in any inpatient location where denominator data can be
collected, which may include critical/intensive care units (ICU), specialty care areas (SCA), stepdown units,
wards, and long term care units. Surveillance will NOT be performed in Neonatal Intensive Care Units
(NICU) or Well Baby Nurseries.
Requirements: Surveillance for CDI should be performed in at least one location in the healthcare
institution for at least 3 calendar months as indicated in the Patient Safety Monthly Reporting Plan (CDC
57.106).
Definitions:
Report all healthcare-associated infections where C. difficile is the associated pathogen. Refer to specific
definitions (Chapter 17) for gastroenteritis (GI-GE) or gastrointestinal tract (GI-GIT) infections criteria.
Cases of CDI (i.e., C. difficile pathogen identified with a positive toxin result) that are not present or
incubating at the time of admission (i.e., meets criteria for a healthcare-associated infection) should be
reported as gastroenteritis (GI-GE) or gastrointestinal tract (GI-GIT) infections, whichever is appropriate.

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MDRO and CDI Module

Report the pathogen as C. difficile on the MDRO or CDI Infection Event form (CDC 57.126). If the patient
develops both GI-GE and GI-GIT CDI, report only GI-GIT using the date of onset as that of GI-GE CDI.
(This CDI HAI reporting corresponds to surveillance for healthcare-onset, healthcare facility-associated
CDI in recently published recommendations3, which is considered the minimum surveillance for CDI.)
CDI Complications: CDI in a case patient within 30 days after CDI symptom onset with the following:
Admission to an intensive care unit for complications associated with CDI (e.g., for shock that requires
vasopressor therapy);
Surgery (e.g., colectomy) for toxic megacolon, perforation, or refractory colitis;
AND/OR
Death caused by CDI within 30 days after symptom onset and occurring during the hospital admission.
Location of Attribution and Transfer Rule applies – See Key Terms.
Numerator and Denominator Data: The numerator data are reported on the MDRO or CDI Infection
Event form (CDC 57.126). (See Tables of Instructions, Table 19, for completion instructions). The patient
day denominator data are reported using the MDRO and CDI and Outcome Measures Monthly Monitoring
form (CDC 57.127). (See Tables of Instructions, Table 21, for completion instructions.)
C. Difficile Infections:
Numerator: The total number of HAI CDI cases identified during the surveillance month.
Denominator: The total number of patient days during the surveillance month.
Data Analysis: Data are stratified by time (e.g., month, quarter, etc.) and by patient care location.
C. difficile Infection rate = Number of HAI CDI cases / Number of patient days X 10,000

Option 2. Clostridium difficile Laboratory-identified Event
Settings: LabID Event reporting can be performed either Overall facility-wide inpatient (FacWideIN),
Overall facility-wide outpatient (FacWideOUT), or in multiple locations, where C. difficile testing in the
laboratory is performed routinely only on unformed (i.e., conforming to the shape of the container) stool
samples. Consider including C. difficile toxin-positive laboratory assays from all available inpatient
locations as well as all available outpatient locations where care is provided to patients post discharge or
prior to admission (e.g., emergency departments, outpatient clinics, and physician offices that submit
samples to the facility’s laboratory.) Surveillance will NOT be performed in Neonatal Intensive Care Units
(NICU), Well Baby Nurseries, or Well Baby Clinics.
Requirements: Facilities must choose one or more of three reporting choices: (Method A) report LabID
Events for the entire facility, but by each location (Facility-wide by location), requiring separate
denominator submissions for each location, (Method B) report LabID Events for only Selected locations,
and (Method C) Overall facility-wide (with only one denominator for the entire facility) (Options include

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MDRO and CDI Module

Overall Facility-wide Inpatient – FacWideIN or Overall Facility-wide Outpatient – FacWideOUT) (See
Table 1). Facilities must indicate each reporting choice chosen for the calendar month indicated in the
Patient Safety Monthly Reporting Plan (CDC 57.106). Facilities reporting Overall facility-wide, which
allows for the most complete data acquisition, can also report by Selected locations (i.e., (C) and (B));
otherwise, facilities must choose between choice (A) alone, (B) alone, or (C) alone (See Table 1).
Surveillance for LabID Events must be reported for 3 consecutive months to provide meaningful measures.
Definitions:
CDI-positive laboratory assay:
A positive laboratory test result for C. difficile toxin A and/or B,
OR
A toxin-producing C. difficile organism detected by culture or other laboratory means performed on a stool
sample.
Duplicate C. difficile-positive test: Any C. difficile toxin-positive laboratory result from the same patient
and location, following a previous C. difficile toxin-positive laboratory result within the past two weeks (14
days). There should be a full 14 days with no C. difficile toxin-positive laboratory result for the patient and
location, before another C. difficile LabID Event is entered into NHSN for the patient and location.
Laboratory-Identified (LabID) Event: All non-duplicate C. difficile toxin-positive laboratory results. Can
include specimens collected during an Emergency Department or other outpatient clinic visit, if collected
same day as patient admission. (See Algorithm Figure 2.)
Numerator: Data will be reported using the Laboratory-Identified MDRO or CDI Event form (CDC
57.128). (See Tables of Instructions, Table 20, for completion instructions.)
Denominator: Patient days, admissions, (for inpatient locations) and encounters (for ER and outpatient
locations) are reported using the MDRO and CDI Prevention Process and Outcome Measures Monthly
Monitoring form (CDC 57.127). (See Tables of Instructions, Table 21, for completion instructions.) When
performing facility-wide inpatient (FacWideIN) or facility-wide outpatient (FacWideOUT) LabID Event
surveillance, denominator counts from neonatal intensive care units, well baby nurseries, and well baby
clinics should NOT be included. Therefore, the specific C. difficile denominator variables should be used
for FacWide reporting. When determining a patient’s admission dates to both the facility and specific
inpatient location, the NHSN user must take into account all such days, including any days spent in an
inpatient location as an “observation” patient before being officially admitted as an inpatient to the facility,
as these days contribute to exposure risk. Therefore, all such days are included in the counts of admissions
and patient days for the facility and specific location, and facility and admission dates must be moved back
to the first day spent in the inpatient location. For further information on counting patient days and
admissions, go to NHSN website>Resource Library>NHSN Guides>Determining Patient Days for
Summary Data Collection: Observation vs. Inpatients.
CDI Data Analysis: Data are stratified by time (e.g., month, quarter, etc.), incident or recurrent, and either
aggregated across the entire facility or stratified by patient care location.

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MDRO and CDI Module

Categorization Based on Current Date Specimen Collected and Prior Date Specimen Collected of a
previous CDI LabID Event:
Incident CDI Assay: Any LabID Event from a specimen obtained > 8 weeks after the most recent LabID
Event (or with no previous LabID Event documented) for that patient.
Recurrent CDI Assay: Any LabID Event from a specimen obtained > 2 weeks and ≤ 8 weeks after the most
recent LabID Event for that patient.
The incident and recurrent CDI LabID Events are further categorized within NHSN. The following
categorizations and prevalence and incidence calculations are built into the analysis capabilities of NHSN,
and are based on timing of admission and specimen collection, location where specimen was collected, and
previous discharge. Descriptions are provided to explain how the categories and metrics are defined in
NHSN.

Categorizing CDI LabID Events – Based on Date Admitted to Facility and Date Specimen Collected:
Community-Onset (CO): LabID Event collected as an outpatient or an inpatient ≤ 3 days after admission to
the facility (i.e., days 1, 2, or 3 of admission).
Community-Onset Healthcare Facility-Associated (CO-HCFA): CO LabID Event collected from a patient
who was discharged from the facility ≤ 4 weeks prior to current date of stool specimen collection.
Healthcare Facility-Onset (HO): LabID Event collected > 3 days after admission to the facility (i.e., on or
after day 4).
Calculated CDI Prevalence Rates:
Inpatient Reporting:
Admission Prevalence Rate = Number of non-duplicate CDI LabID Events per patient per month identified
≤ 3 days after admission to the location (if monitoring by inpatient location), or facility (if monitoring by
overall facility-wide inpatient=FacWideIN) / Number of patient admissions to the location or facility x 100
Location Percent Admission Prevalence that is Community-Onset = Number of Admission Prevalent LabID
Events to a location that are CO / Total number Admission Prevalent LabID Events x 100 (Note: The
numerator in this formula does not include Admission Prevalent LabID Events that are CO-HFCA.)
Location Percent Admission Prevalence that is Community-Onset Healthcare Facility-Associated = Number
of Admission Prevalent LabID Events to a location that are CO-HCFA / Total number Admission Prevalent
LabID Events x 100

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MDRO and CDI Module

Location Percent Admission Prevalence that is Healthcare Facility-Onset = Number of Admission Prevalent
LabID Events to a location that are HO / Total number of Admission Prevalent LabID Events x 100
Overall Patient Prevalence Rate = Number of 1st CDI LabID Events per patient per month regardless of
time spent in location (i.e., prevalent + incident, if monitoring by inpatient location), or facility (i.e., CO +
CO-HCFA + HO, if monitoring by overall facility-wide inpatient=FacWideIN) / Number of patient
admissions to the location or facility x 100
Outpatient Reporting:
Outpatient Prevalence Rate = Number of all non-duplicate CDI LabID Events per patient per month for the
location (if monitoring by outpatient location), or the facility (if monitoring by overall facility-wide
outpatient=FacWideOUT) / Number of patient encounters for the location or facility x 100
Calculated CDI Incidence Rates: (see categorization of Incident, HO, and CO-HCFA above).
Location CDI Incidence Rate = Number of Incident CDI LabID Events per month identified > 3 days after
admission to the location / Number of patient days for the location x 10,000
Facility CDI Healthcare Facility-Onset Incidence Rate = Number of all Incident HO CDI LabID Events per
month in the facility/ Number of patient days for the facility x 10,000 (this calculation is only accurate for
Overall Facility-wide Inpatient reporting)
Facility CDI Combined Incidence Rate = Number of all Incident HO and CO-HCFA CDI LabID Events per
month in the facility / Number of patient days for the facility x 10,000 (this calculation is only accurate for
Overall Facility-wide Inpatient reporting)
B. Optional Reporting
Prevention Process Measures Surveillance (Hand Hygiene and Gown and Gloves Use Only)
See Sections I.B.1.a. and I.B.1.b. under the MDRO Option.

1

HICPAC, Management of Multidrug-Resistant Organisms in Healthcare Settings.
.
2

Cohen AL, et al. Infection Control and Hospital Epidemiology. Oct 2008;29:901-913.

3

McDonald LC, et al. Infect Control Hosp Epidemiol 2007; 28:140-145.

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MDRO and CDI Module

June, 2011

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MDRO and CDI Module

Figure 2. C. difficile Test Result Algorithm for Laboratory Identified (LabID) Events

(+) C. difficile test result

Prior (+) in
≤ 2 weeks
No

Yes

Duplicate C.
difficile test

LabID Event

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Not a LabID
Event

MDRO and CDI Module

Table 2. Rates and Measures Derived from Various MDRO and CDI Protocol Surveillance Methods
Surveillance Forms
Rate
Measures
Method
MDRO
Numerator:
Data are stratified by time (e.g., month,
Direct HAI
Infection
1)Primary Bloodstream year) and patient care location.
MDRO Incidence
Surveillance Infection
Rate
MDRO Infection Incidence Rate = Number
2) Pneumonia
3) Urinary Tract
of healthcare-associated infections by
Infection
MDRO type/ Number of patient days X
4) Surgical Site
1000
Infection
5) MDRO Infection
Event

MDRO
Laboratory
Identified
Event

Denominator:
MDRO and CDI
Prevention Process &
Outcome Measures
Monthly Monitoring
Numerator:
Laboratory Identified
MDRO or CDI Event
Denominator:
MDRO and CDI
Prevention Process &
Outcome Measures
Monthly Monitoring

Inpatient Reporting:
Admission Prevalence Rate = Number of
1st LabID Events per patient per month
identified ≤ 3 days after admission to the
location (if monitoring by inpatient
location), or the facility (if monitoring by
overall facility-wide inpatient=FacWideIN)
/ Number of patient admissions to the
location or facility x 100
Location Percent Admission Prevalence
that is Community-Onset = Number of
Admission Prevalent LabID Events to a
location that are CO / Total number
Admission Prevalent LabID Events x 100
Location Percent Admission Prevalence
that is Healthcare Facility-Onset = Number
of Admission Prevalent LabID Events to a
location that are HO / Total number of
Admission Prevalent LabID Events x 100
Overall Patient Prevalence Rate = Number
of 1st LabID Events per patient per month
regardless of time spent in location (i.e.,

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Proxy Measures
for
MDRO
Exposure Burden

MDRO and CDI Module

Surveillance Forms
Method

Rate

Measures

prevalent + incident, if monitoring by
inpatient location), or facility (i.e., CO +
HO, if monitoring by overall facility-wide
inpatient=FacWideIN) / Number of patient
admissions to the location or facility x 100
Outpatient Reporting:
Outpatient Prevalence Rate = Number of
1st LabID Events per patient per month for
the location (if monitoring by outpatient
location), or the facility (if monitoring by
overall facility-wide outpatient =
FacWideOUT) / Number of patient
encounters for the location or facility x 100
Inpatient Reporting:
MDRO Bloodstream Infection Admission
Prevalence Rate = Number of all unique
blood source LabID Events per patient per
month identified ≤ 3 days after admission to
the location (if monitoring by inpatient
location), or facility (if monitoring by
overall facility-wide inpatient=FacWideIN)
/ Number of patient admissions to the
location or facility x 100
MDRO Bloodstream Infection Incidence
OR Incidence Density Rate = Number of all
unique blood source LabID Events per
patient per month identified > 3 days after
admission to the location (if monitoring by
inpatient location), or facility (if monitoring
by overall facility-wide inpatient =
FacWideIN) / Number of patient
admissions to the location or facility x 100
OR Number of patient days for the location
or facility x 1,000
MDRO Bloodstream Infection Overall
Patient Prevalence Rate = Number of 1st
Blood LabID Events per patient per month
regardless of time spent in location (i.e.,
prevalent + incident, if monitoring by

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Proxy Measures
for
Bloodstream
Infection
Admission
Prevalence and
Incidence

MDRO and CDI Module

Surveillance Forms
Method

Rate

Measures

inpatient location), or facility (i.e., CO +
HO, if monitoring by overall facility-wide
inpatient=FacWideIN) / Number of patient
admissions to the location or facility x 100
Outpatient Reporting:
MDRO Bloodstream Infection Outpatient
Prevalence Rate = Number of all unique
blood source LabID Events per patient per
month for the location (if monitoring by
outpatient location), or the facility (if
monitoring by overall facility-wide
outpatient=FacWideOUT) / Number of
patient encounters for the location or
facility x 100
Overall MDRO Infection/Colonization
Incidence Rate = Number of 1st LabID
Events per patient per month among those
with no documented prior evidence of a
previous LabID Event with this specific
organism type and identified > 3 days after
admission to the location (if monitoring by
inpatient location), or facility (if monitoring
by overall facility-wide inpatient =
FacWideIN) / Number of patient
admissions to the location or facility x 100

Proxy Measures
for
MDRO Healthcare
Acquisition

Overall MDRO Infection/Colonization
Incidence Density Rate = Number of 1st
LabID Events per patient per month among
those with no documented prior evidence of
a previous LabID Event with this specific
organism type and identified > 3 days after
admission to the location (if monitoring by
inpatient location), or facility (if
monitoring by overall facility-wide
inpatient=FacWideIN) / Number of patient
days for the location or facility x 1,000
Prevention
Process
Measures:

June, 2011

Numerator &
Denominator:
MDRO and CDI
Prevention Process &

Direct Adherence
Percent:
Hand Hygiene Percent Adherence =
Number of contacts for which hand hygiene

12 - 25

Hand Hygiene

MDRO and CDI Module

Surveillance Forms
Method
Hand
Outcome Measures
Hygiene
Monthly Monitoring

Rate

Gown &
Gloves Use

Gown & Glove Use Percent Adherence =
Number of contacts during which gown and
gloves were used /Number of contacts for
which gown and gloves were indicated X
100.

Gown & Gloves
Use

Active
Surveillance
Testing
(AST)
(MRSA &
VRE only)

Admission AST Percent Adherence =
Number of patients with admission AST
performed / Number of patients admission
AST eligible X 100

Admission AST

Active
Surveillance
Testing
Outcome
Measures
(MRSA &
VRE Only)

Measures

was performed / Number of contacts for
which hand hygiene was indicated X 100

Discharge/transfer AST Percent Adherence
= Number of patients with
discharge/transfer AST performed /
Number of patients discharge/transfer AST
eligible X 100.
Numerator &
Denominator:
MDRO and CDI
Prevention Process &
Outcome Measures
Monthly Monitoring

Eligible patients =
All
(All patients
regardless of history
of MDRO)
AST Admission
Prevalence rate =
Number of
admission AST or
clinical positive /
Number of
admissions X 100

Eligible patients =
NHx
(No history)

12 - 26

Direct Admission
Prevalence Rates
of MDRO by AST
Eligibility

AST Admission
Prevalence rate =
Number of
admission AST or
clinical positive +
Number of known
positive / Number of
admissions X 100.

AST Incidence Rate = Number of
discharge/transfer AST or clinical positive
cases / Number of patient days X 1000

June, 2011

Discharge/Transfer
AST

Direct MDRO
Healthcare
Acquisition

MDRO and CDI Module

Surveillance Forms
Method
CDI
Numerator:
Infection
CDI Infection Event
Surveillance
Denominator:
MDRO and CDI
Prevention Process &
Outcome Measures
Monthly Monitoring
CDI
Numerator:
Laboratory
Laboratory-Identified
Identified
MDRO or CDI Event
Event
Denominator:
MDRO and CDI
Prevention Process &
Outcome Measures
Monthly Monitoring

Rate

C. Difficile Infection rate = Number of C.
difficile healthcare-associated infections/
Number of patient days X 10,000

Inpatient Reporting:
Admission Prevalence Rate = Number of
non-duplicate CDI LabID Events per
patient per month identified ≤ 3 days after
admission to the location (if monitoring by
inpatient location), or facility (if monitoring
by overall facility-wide inpatient =
FacWideIN) / Number of patient
admissions to the location or facility x 100
Location Percent Admission Prevalence
that is Community-Onset = Number of
Admission Prevalent LabID Events to a
location that are CO / Total number
Admission Prevalent LabID Events x 100
Location Percent Admission Prevalence
that is Community-Onset Healthcare
Facility-Associated = Number of
Admission Prevalent LabID Events to a
location that are CO-HCFA / Total number
Admission Prevalent LabID Events x 100
Location Percent Admission Prevalence
that is Healthcare Facility-Onset = Number
of Admission Prevalent LabID Events to a
location that are HO / Total number of
Admission Prevalent LabID Events x 100
Overall Patient Prevalence Rate = Number
of 1st CDI LabID Events per patient per
month regardless of time spent in location
(i.e., prevalent + incident, if monitoring by
inpatient location), or facility (i.e., CO +

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Measures
Direct HAI CDI
Incidence Rate

Proxy Measures
for
CDI Exposure
Burden

MDRO and CDI Module

Surveillance Forms
Method

Rate

Measures

CO-HCFA + HO, if monitoring by overall
facility-wide inpatient=FacWideIN) /
Number of patient admissions to the
location or facility x 100
Outpatient Reporting:
Outpatient Prevalence Rate = Number of
all non-duplicate CDI LabID Events per
patient per month for the location (if
monitoring by outpatient location), or the
facility (if monitoring by overall facilitywide outpatient=FacWideOUT) / Number
of patient encounters for the location or
facility x 100
Location CDI Incidence Rate = Number of
Incident CDI LabID Events per month
identified > 3 days after admission to the
location / Number of patient days for the
location x 10,000
Facility CDI Healthcare Facility-Onset
Incidence Rate = Number of all Incident
HO CDI LabID Events per month in the
facility/ Number of patient days for the
facility x 10,000 (this calculation is only
accurate for Overall Facility-wide Inpatient
reporting)
Facility CDI Combined Incidence Rate =
Number of all Incident HO and CO-HCFA
CDI LabID Events per month in the facility
/ Number of patient days for the facility x
10,000 (this calculation is only accurate for
Overall Facility-wide Inpatient reporting)

June, 2011

12 - 28

Proxy Measures
for
CDI Healthcare
Acquisition