4

April 2013 CDC/NHSN Protocol Corrections,
Clarification, and Additions
(NOTE: These protocol edits have not yet been added to the current posted
NHSN protocols)
•

Errata [PDF - 291 KB] April 2013

Device-associated Module
CLABSI

Central Line-Associated Bloodstream Infection (CLABSI) Event
Introduction: An estimated 41,000 central line-associated bloodstream infections
(CLABSI) occur in U.S. hospitals each year.1 These infections are usually serious
infections typically causing a prolongation of hospital stay and increased cost and risk of
mortality.
CLABSI can be prevented through proper insertion techniques and management of the
central line. These techniques are addressed in the CDC’s Healthcare Infection Control
Practices Advisory Committee (CDC/HIPAC) Guidelines for the Prevention of
Intravascular Catheter-Related Infections, 2011.2
Settings: 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), neonatal units including neonatal intensive care units (NICUs), step down units,
wards, and long term care units. A complete listing of inpatient locations and instructions
for mapping can be found in the CDC Locations and Descriptions chapter.
NOTE: Surveillance for CLABSIs after the patient is discharged from the facility is not
required. However, if discovered, any CLABSIs occurring on the day of discharge or the
next day, should be reported to NHSN (see Transfer Rule). No additional central line
days are reported.
Requirements: Surveillance for HAI CLABSI is performed in at least one inpatient
location in the healthcare institution for at least one calendar month as indicated in the
Patient Safety Monthly Reporting Plan (CDC 57.106).
Definitions:
Healthcare-associated infections (HAI): An infection is considered an HAI if all elements
of a CDC/NHSN site-specific infection criterion were first present together on or after the
3rd hospital day (day of hospital admission is Day 1). For an HAI, an element of the
infection criterion may be present during the first 2 hospital days as long as it is also
present on or after Day 3. All elements used to meet the infection criterion must occur
within a timeframe that does not exceed a gap of 1 calendar day between elements.
Primary bloodstream infections (BSI) are laboratory-confirmed bloodstream infections
(LCBI) that are not secondary to an infection at another body site (see Appendix 1.
Secondary Bloodstream Infection (BSI) Guide and HAI Definitions chapter).
Date of event: For a BSI the date of event is the date when the last element used to meet
the laboratory-confirmed bloodstream infection (LCBI) criterion occurred. Synonyms:
infection date, date of infection.
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Central line: An intravascular catheter that terminates at or close to the heart or in one of
the great vessels which is used for infusion, withdrawal of blood, or hemodynamic
monitoring. The following are considered great vessels for the purpose of reporting
central-line BSI and counting central-line days in the NHSN system:
• Aorta
• Pulmonary artery
• Superior vena cava
• Inferior vena cava
• Brachiocephalic veins
• Internal jugular veins
• Subclavian veins
• External iliac veins
• Common iliac veins
• Femoral veins
• In neonates, the umbilical artery/vein.
NOTES:
1.
Neither the insertion site nor the type of device may be used to determine if a line
qualifies as a central line. The device must terminate in one of the great vessels
or in or near the heart and be used for one of the purposes outlined above, to
qualify as a central line.
2.
An introducer is considered an intravascular catheter, and depending on the
location of its tip and use, may be a central line.
3.
Pacemaker wires and other nonlumened devices inserted into central blood
vessels or the heart are not considered central lines, because fluids are not infused,
pushed, nor withdrawn through such devices.
4.
The following devices are not considered central lines:
• Extracorporeal membrane oxygenation (ECMO)
• Femoral arterial catheters
• Intraaortic balloon pump (IABP) devices.
Infusion: The introduction of a solution through a blood vessel via a catheter lumen. This
may include continuous infusions such as nutritional fluids or medications, or it may
include intermittent infusions such as flushes, IV antimicrobial administration, or blood
transfusion or hemodialysis.
Umbilical catheter: A central vascular device inserted through the umbilical artery or vein
in a neonate.
Temporary central line: A non-tunneled or implanted catheter.
Permanent central line: Includes
• Tunneled catheters, including certain dialysis catheters
• Implanted catheters (including ports)

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Central line-associated BSI (CLABSI): A laboratory-confirmed bloodstream infection
(LCBI) where central line (CL) or umbilical catheter (UC) was in place for >2 calendar
days when all elements of the LCBI infection criterion were first present together, with
day of device placement being Day 1,
and
a CL or UC was in place on the date of event or the day before. If the patient is admitted
or transferred into a facility with a central line in place (e.g., tunneled or implanted
central line), day of first access is considered Day1.
EXAMPLES:
• Patient in MICU has central line inserted/accessed on June 1. On June 3, the
central line is still in place and the patient has positive blood culture with S.
aureus. This is a CLABSI because the central line was in place for >2 calendar
days when all elements of LCBI Criterion 1 were first present together.
• Patient has a central line inserted on June 1. On June 3, the central line is
discontinued and on June 4 the patient has a positive blood culture with S. aureus.
This is a CLABSI because the central line was in place for >2 calendar days (June
1, 2, and 3) and was in place the day before all elements of LCBI Criterion 1 were
first present together.
• On June 3, central line is discontinued and on June 4 patient spikes a fever of
38.3°C. Two blood culture sets collected on June 5 are positive for S. epidermidis.
This is may be a healthcare-associated bloodstream infection but it is not a
CLABSI because the central line was not place the day of or the day before all
elements of LCBI Criterion 2 were first present together (June 5).
Location of attribution: The inpatient location where the patient was assigned on the date
of the BSI event, which is further defined as the date when the last element used to meet
the BSI criterion occurred (see exception below).
NOTE:
When hemodialysis through a central line is provided by contracted staff members who
are not employees of the facility, CLABSIs that are identified in these patients are
attributed to the inpatient location where the patient was assigned. Facilities are
responsible for the care provided within their confines and infection prevention issues
related to contracted staff or their agencies should be addressed by the facility.
EXCEPTION TO LOCATION OF ATTRIBUTION:
Transfer Rule: If all elements of a CLABSI are present within 2 calendar days of transfer
from one inpatient location to another in the same facility or a new facility (i.e., on the
day of transfer or the next day), the infection is attributed to the transferring location or
facility. Receiving facilities should share information about such HAIs with the
transferring facility to enable reporting. This is called the Transfer Rule and examples are
shown below:
• Patient with a central line in place in the SICU is transferred to the surgical ward.
On the next day, all elements of LCBI are first present together. This is reported
to NHSN as a CLABSI for the SICU.
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•

•

•

Patient without a central line is transferred from the medical ward to MICU. Later
that day a central line is inserted. The next day, all elements of LCBI are first
present together. This would be considered a BSI and attributed to the medical
ward; however, it is not a CLABSI because the central line was not in place >2
days before all elements of LCBI were first present together.
Patient with a central line in place is transferred from the medical ward to the
coronary care ICU (CCU). After 4 days in the CCU and with the central line still
in place, all elements of LCBI are first present together. This is reported to
NHSN as a CLABSI for the CCU.
Patient on the urology ward of Hospital A had the central line removed and is
discharged home a few hours later. The IP from Hospital B calls the next day to
report that this patient has been admitted to Hospital B and meets all elements of
LCBI criteria. This CLABSI should be reported to NHSN for, and by, Hospital A
and attributed to the urology ward.

EXCEPTION TO TRANSFER RULE:
Locations which do not house patients overnight (e.g., Emergency Department or
Operating Room) will have no denominator data, i.e., patient days or central line days.
Therefore, CLABSIs cannot be attributed to these locations. Instead, the CLABSI must
be attributed to the next inpatient location in which the patient stays.
EXAMPLE:
• Patient, who had no clinical signs or symptoms of sepsis upon arrival to the
Emergency Department, has a central line inserted there and then is admitted to
the MICU on the same day. All elements of LCBI are first present together on
MICU Day 3. This is reported as a CLABSI for the MICU because all elements of
LCBI are first present together >2 calendar days after hospital admission and the
central line was in place for >2 calendar days.

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Table 1. Laboratory-Confirmed Bloodstream Infection Criteria
Criterion

Laboratory-Confirmed Bloodstream Infection (LCBI)
Comments and reporting instructions that follow the site-specific
criteria provide further explanation and are integral to the correct
application of the criteria.
Must meet one of the following criteria:

LCBI 1

Patient has a recognized pathogen cultured from one or more blood
cultures
and
organism cultured from blood is not related to an infection at
another site.

LCBI 2

Patient has at least one of the following signs or symptoms: fever
(>38oC), chills, or hypotension
and
positive laboratory results are not related to an infection at another
site
and
common commensal (i.e., diphtheroids [Corynebacterium spp. not
C. diphtheriae], Bacillus spp. [not B. anthracis], Propionibacterium
spp., coagulase-negative staphylococci [including S. epidermidis],
viridans group streptococci, Aerococcus spp., and Micrococcus
spp.) is cultured from two or more blood cultures drawn on separate
occasions. Criterion elements must occur within a timeframe that
does not exceed a gap of 1 calendar day.
(See complete list of common commensals at

http://www.cdc.gov/nhsn/XLS/master-organism-Com-Commensals-Lists.xls)

LCBI 3

Patient ≤ 1 year of age has at least one of the following signs or
symptoms: fever (>38oC core) hypothermia (<36oC core), apnea,
or bradycardia
and
positive laboratory results are not related to an infection at another
site
and

January 2013

common skin commensal (i.e., diphtheroids [Corynebacterium spp.
not C. diphtheriae], Bacillus spp. [not B. anthracis],
Propionibacterium spp., coagulase-negative staphylococci
[including S. epidermidis], viridans group streptococci, Aerococcus
spp., Micrococcus spp.) is cultured from two or more blood cultures
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drawn on separate occasions. Criterion elements must occur within
a timeframe that does not exceed a gap of 1 calendar day.
(See complete list of common commensals at

http://www.cdc.gov/nhsn/XLS/master-organism-Com-Commensals-Lists.xlsx)

Criterion

Mucosal Barrier Injury Laboratory-Confirmed Bloodstream
Infection (MBI-LCBI)
In 2013 when reporting an LCBI, it is optional to indicate which of
the underlying conditions of the MBI-LCBI criterion was met, if
any. However, all CLABSI, whether LCBI or MBI-LCBI, must be
reported if CLABSI is part of your Monthly Reporting Plan.
Must meet one of the following criteria:

MBI-LCBI 1

Patient of any age meets criterion 1 for LCBI with at least one
blood culture growing any of the following intestinal organisms
with no other organisms isolated: Bacteroides spp., Candida spp.,
Clostridium spp., Enterococcus spp., Fusobacterium spp.,
Peptostreptococcus spp., Prevotella spp., Veillonella spp., or
Enterobacteriaceae*
and
patient meets at least one of the following:
1. Is an allogeneic hematopoietic stem cell transplant recipient
within the past year with one of the following documented
during same hospitalization as positive blood culture:
a. Grade III or IV gastrointestinal graft versus host
disease (GI GVHD)
b. ≥1 liter diarrhea in a 24-hour period (or ≥20 mL/kg
in a 24-hour period for patients <18 years of age)
with onset on or within 7 calendar days before the
date the positive blood culture was collected.
2. Is neutropenic, defined as at least 2 separate days with
values of absolute neutrophil count (ANC) or total white
blood cell count (WBC) <500 cells/mm3 on or within 3
calendar days before the date the positive blood culture was
collected (Day 1). (See Table 4 for example.)
*See Table 3 for partial list of eligible Enterobacteriaceae genera.

MBI-LCBI 2

Patient of any age meets criterion 2 for LCBI when the blood
cultures are growing only viridans group streptococci with no other
organisms isolated
and

January 2013

patient meets at least one of the following:
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1. Is an allogeneic hematopoietic stem cell transplant recipient
within the past year with one of the following documented
during same hospitalization as positive blood culture:
a. Grade III or IV gastrointestinal graft versus host
disease (GI GVHD)
b. ≥1 liter diarrhea in a 24-hour period (or ≥20 mL/kg
in a 24-hour period for patients <18 years of age)
with onset on or within 7 calendar days before the
date the first positive blood culture was collected.
2. Is neutropenic, defined as at least 2 separate days with
values of absolute neutrophil count (ANC) or total white
blood cell count (WBC) <500 cells/mm3 on or within 3
calendar days before the date the positive blood culture was
collected (Day 1). (See Table 4 for example.)
MBI-LCBI 3

Patient ≤1 year of age meets criterion 3 for LCBI when the blood
cultures are growing only viridans group streptococci with no other
organisms isolated
and
patient meets at least one of the following:
1. Is an allogeneic hematopoietic stem cell transplant recipient
within the past year with one of the following documented
during same hospitalization as positive blood culture:
a. Grade III or IV gastrointestinal graft versus host
disease (GI GVHD)
b. ≥20 mL/kg in a 24-hour period with onset on or
within 7 calendar days before the date the first
positive blood culture is collected.
2. Is neutropenic, defined as at least 2 separate days with
values of absolute neutrophil count (ANC) or total white
blood cell count (WBC) <500 cells/mm3 on or within 3
calendar days before the date the positive blood culture was
collected (Day 1). (See Table 4 for example.)

Comments

January 2013

1. In LCBI criterion 1, the phrase “one or more blood cultures”
means that at least one bottle from a blood draw is reported by
the laboratory as having grown at least one organism (i.e., is a
positive blood culture).
2. In LCBI criterion 1, the term “recognized pathogen” does not
include organisms considered common commensals (see criteria
2 and 3 for the list of common commensals). A few of the
recognized pathogens are S. aureus, Enterococcus spp., E. coli,
Pseudomonas spp., Klebsiella spp., Candida spp., etc.
3. In LCBI criteria 2 and 3, the phrase “two or more blood cultures
drawn on separate occasions” means 1) that blood from at least
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two blood draws were collected within two calendar days of
each other (e.g., blood draws on Monday and Tuesday would be
acceptable for blood cultures drawn on separate occasions, but
blood draws on Monday and Wednesday would be too far apart
in time to meet this criterion), and 2) that at least one bottle
from each blood draw is reported by the laboratory as having
grown the same common commensal (i.e., is a positive blood
culture). (See Comment 4 for determining sameness of
organisms.)
a. For example, an adult patient has blood drawn at 8 a.m.
and again at 8:15 a.m. of the same day. Blood from each
blood draw is inoculated into two bottles and incubated
(four bottles total). If one bottle from each blood draw
set is positive for coagulase-negative staphylococci, this
part of the criterion is met.
b. For example, a neonate has blood drawn for culture on
Tuesday and again on Thursday and both grow the same
common commensal. Because the time between these
blood cultures exceeds the 2-day period for blood draws
stipulated in LCBI and MBI-LCBI criteria 2 and 3, this
part of the criterion is not met.
c. “Separate occasions” also means blood draws collected
from separate sites or separate accesses of the same site,
such as two draws from a single lumen catheter or draws
from separate lumens of a catheter. In the latter case, the
draws may be just minutes apart (i.e., just the time it
takes to disinfect and draw the specimen from each
lumen). For example, a patient with a triple lumen central
line has blood drawn from each lumen within 15 minutes
of each other. Each of these is considered a separate
blood draw.
d. A blood culture may consist of a single bottle for a
pediatric blood draw due to volume constraints.
Therefore, to meet this part of the criterion, each bottle
from two or more draws would have to be culturepositive for the same commensal.
4. If the pathogen or common commensal is identified to the
species level from one blood culture, and a companion blood
culture is identified with only a descriptive name (e.g., to the
genus level), then it is assumed that the organisms are the same.
The organism identified to the species level should be reported
as the infecting organism along with its antibiogram if available
(see Table 2 below).
5. Only genus and species identification should be utilized to
determine the sameness of organisms (i.e., matching
organisms). No additional comparative methods should be used
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6.
7.

8.

9.

REPORTING
INSTRUCTIONS

January 2013

(e.g., morphology or antibiograms) because laboratory testing
capabilities and protocols may vary between facilities. This will
reduce reporting variability, solely due to laboratory practice,
between facilities reporting LCBIs meeting criterion 2. Report
the organism to the genus/species level only once, and if
antibiogram data are available, report the results from the most
resistant panel.
LCBI criteria 1 and 2 and MCI-LCBI criteria 1 and 2 may be
used for patients of any age, including these patients ≤1 year of
age.
Specimen Collection Considerations: Ideally, blood specimens
for culture should be obtained from two to four blood draws
from separate venipuncture sites (e.g., right and left antecubital
veins), not through a vascular catheter. These blood draws
should be performed simultaneously or over a short period of
time (i.e., within a few hours).3,4 If your facility does not
currently obtain specimens using this technique, you must still
report BSIs using the criteria and comments above, but you
should work with appropriate personnel to facilitate better
specimen collection practices for blood cultures.
“No other organisms isolated” means there is not isolation in a
blood culture of another recognized pathogen (e.g., S. aureus)
or common commensal (e.g., coagulase-negative staphylococci)
other than listed in MBI-LCBI criterion 1, 2 or 3 that would
otherwise meet LCBI criteria. If this occurs, the infection
should not be classified as MBI-LCBI.
Grade III/IV GI GVHD is defined as follows:
• In adults: ≥1 L diarrhea/day or ileus with abdominal
pain
• In pediatric patients: ≥20 cc/kg/day of diarrhea

1. Report organisms cultured from blood as BSI–LCBI when no
other site of infection is evident (see Appendix 1. Secondary
Bloodstream Infection (BSI) Guide.
2. Catheter tip cultures are not used to determine whether a patient
has a primary BSI.
3. When there is a positive blood culture and clinical signs or
symptoms of localized infection at a vascular access site, but no
other infection can be found, the infection is considered a
primary BSI.
4. Purulent phlebitis confirmed with a positive semiquantitative
culture of a catheter tip, but with either negative or no blood
culture is considered a CVS-VASC, not a BSI nor an SST-SKIN
or ST infection.
5. Occasionally a patient with both peripheral and central IV lines
develops a primary bloodstream infection (LCBI) that can
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clearly be attributed to the peripheral line (e.g., pus at the
insertion site and matching pathogen from pus and blood). In
this situation, enter “Central Line = No” in the NHSN
application. You should, however, include the patient’s central
line days in the summary denominator count.
6. If your state or facility requires that you report healthcareassociated BSIs that are not central line-associated, enter
“Central Line = No” in the NHSN application when reporting
these BSIs. You should, however, include all of the patient’s
central line days in the summary denominator count.

Table 2. Examples of How to Report Speciated and Unspeciated Organisms Isolated
from Blood Cultures
Culture Report

Companion Culture
Report

Report as…

Coagulase-positive staphylococci

S. aureus

S. aureus

S. epidermidis

Coagulase-negative
staphylococci

S. epidermidis

Enterococcus spp.

E. faecium

E. faecium

Bacillus spp. (not anthracis)

B. cereus

B. cereus

S. salivarius

Strep viridans

S. salivarius

Table 3. Partial List of Criterion 1 MBI-LCBI Eligible Enterobacteriaceae Genera
(See complete list of MBI Pathogens at http://www.cdc.gov/nhsn/XLS/master-organism-Com-Commensals-Lists.xlsx)

Citrobacter
Enterobacter
Escherichia
Klebsiella
Proteus
Providencia
Salmonella
Serratia
Shigella
Yersina

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Table 4. Examples Illustrating the MBI-LCBI Criteria for Neutropenia

Pt. A

Pt. B

Day
-7
WBC 100

ANC

ND

Day
-6
800

410

Day
-5
400

130

Day
-4
300

ND

Day
-3
ND

ND

Day
-2
ND

120

Day
-1
320

Day
1*

400

110

+ BC* w/
Candida spp.
x1
ND

Day
2
230

110

+BC* w/
viridans strep
x2 and fever
>38°C

ND = not done
*Day the blood specimen that was positive was collected
Patient A meets MBI-LCBI criterion 1, sub-criterion 2: Positive blood culture with
intestinal organism (Candida spp.) and neutropenia (2 separate days of WBC <500
cells/mm3 occurring on the date the positive blood culture was collected [Day 1, value =
400] or during the 3 days before that date [in this case, the day before or Day -1; value =
320]).
Patient B meets MBI-LCBI criterion 2, sub-criterion 2: At least 2 positive blood cultures
with viridans group streptococci (in this case, 2 positive), and fever >38°C and
neutropenia (2 separate days of ANC <500 cells/mm3 occurring on the date the positive
blood culture was collected [Day 1] or during the 3 days before that date [in this case, the
two days before or Days -1 and -2; values = 110 and 120]).
Numerator Data: The Primary Bloodstream Infection (BSI) form (CDC 57.108) is used
to collect and report each CLABSI that is identified during the month selected for
surveillance. The Instructions for Completion of Primary Bloodstream Infection (BSI)
form contains brief instructions for collection and entry of each data element on the form.
The Primary BSI form includes patient demographic information and whether a central
line was present, and, if so, the type of central line the patient had if appropriate to the
location; these data will be used to calculate line-specific infection rates. Additional data
include the specific criteria met for identifying the primary BSI, whether the patient died,
the organisms isolated from blood cultures, and the organisms’ antimicrobial
susceptibilities.
REPORTING INSTRUCTION:
• If no CLABSIs are identified during the month of surveillance, the Report No
Events box must be checked on the appropriate denominator summary screen,
e.g., Denominators for Intensive Care Unit (ICU)/Other locations (Not NICU or
SCA), etc.
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Denominator Data: Device days and patient days are used for denominators (see Key
Terms chapter). Device-day denominator data that are collected differ according to the
location of the patients being monitored; however, they should be collected at the same
time each day. When denominator data are available from electronic databases, these
sources may be used as long as the counts are not substantially different (+/- 5%) from
manually-collected counts, validated for a minimum of 3 months.
For locations other than specialty care areas/oncology (SCA/ONC) and NICUs, the
number of patients with one or more central lines of any type is collected daily, at the
same time each day, during the month and recorded on the Denominators for Intensive
Care Unit (ICU)/Other Locations (Not NICU or SCA/ONC) form (CDC 57.118). Only
the totals for the month are entered into NHSN. When denominator data are available
from electronic sources (e.g., central line days from electronic charting), these sources
may be used as long as the counts are not substantially different (+/- 5%) from manuallycollected counts, validated for a minimum of 3 months.
For specialty care areas/oncology, the number of patients with one or more central lines
is dichotomized into those with permanent central lines and those with temporary central
lines on the Denominators for Specialty Care Area (SCA)/Oncology (ONC) form (CDC
57.117). Each is collected daily, at the same time each day. Only the totals for the month
are entered into NHSN. This distinction in lines is made because permanent lines are
commonly used in patients frequenting these areas and may be associated with lower
rates of BSI than central lines inserted for temporary use. If a patient has both a
temporary and a permanent central line, count the day only as a temporary line day. The
Instructions for Completion of Denominators for Intensive Care Unit (ICU)/Other
Locations (Not NICU and SCA/ONC) and Instructions for Completion of Denominators
for Specialty Care Areas (SCA)/Oncology (ONC) contain brief instructions for collection
and entry of each data element on the forms.
In NICUs, the number of patients with one or more central lines is stratified by
birthweight in five categories since risk of BSI varies by birthweight. These data are
collected on the Denominators for Neonatal Intensive Care Unit (NICU) form (CDC
57.116).
NOTE: The weight of the infant at the time of BSI is not used and should not be
reported. For example, if a neonate weighs 1006 grams at birth but remains in the NICU
for two months and has a body weight of 1650 grams when a CLABSI develops, record
the birthweight of 1006 grams on the BSI form. The Instructions for Completion of
Denominators for Neonatal Intensive Care Unit (NICU) form contains brief instructions
for collection and entry of each data element on the forms.
Data Analyses: The Standardized Infection Ratio (SIR)6 is calculated by dividing the
number of observed infections by the number of expected infections. The number of
expected infections, in the context of statistical prediction, is calculated using CLABSI
rates from a standard population during a baseline time period, which represents a
standard population’s CLABSI experience.7
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NOTE: The SIR will be calculated only if the number of expected HAIs (numExp) is ≥1.

While the CLABSI SIR can be calculated for single locations, the measure also allows
you to summarize your data across multiple locations, adjusting for differences in the
incidence of infection among the location types. For example, you will be able to obtain
one CLABSI SIR adjusting for all locations reported. Similarly, you can obtain one
CLABSI SIR for all specialty care areas in your facility.
The CLABSI rate per 1000 central line days is calculated by dividing the number of
CLABSI by the number of central line days and multiplying the result by 1000. The
Central Line Utilization Ratio is calculated by dividing the number of central line days by
the number of patient days. These calculations will be performed separately for different
types of ICUs, specialty care areas, and other locations in the institution. Separate rates
and ratios will also be calculated for different types of catheters in specialty care
areas/oncology and for birthweight categories in NICUs.
1

CDC Vital Signs. Making healthcare safer: reducing bloodstream infections. March 2011. Available at:
http://www.cdc.gov/VitalSigns/HAI/index.html.

2

O’Grady NP, Alexander M, Burns LA,, Dellinger EP, Garland J, Heard SO, Maki DG, et al. Guidelines
for the prevention of intravascular catheter-related infections, 2011. Clinical Infectious Diseases 2011; 52
(a):1087-99.

3

Clinical and Laboratory Standards Institute (CLSI). Principles and Procedures for Blood Cultures;
Approved Guideline. CLSI document M47-A (ISBN 1-56238-641-7). Clinical and Laboratory Standards
Institute, 940 West Valley Road, Suite 1400, Wayne, Pennsylvania, USA, 2007.
4

Baron EJ, Weinstein MP, Dunne Jr WM, Yagupsky P, Welch DF, and Wilson DM. Cumitech IC: Blood
Cultures IV. ASM Press: Washington, DC; 2005.

5

Lee, A, Mirrett, S., Reller, LB., Weinstein, MP. Detection of bloodstream infections in adults: how many
blood cultures are needed? Journal of Clinical Microbiology, 2007; Nov;45(11): 3546-8. Epub 2007 Sep
19.

6

Your guide to the Standardized Infection Ratio (SIR). October 2010.
http://www.cdc.gov/nhsn/PDFs/Newsletters/NHSN_NL_OCT_2010SE_final.pdf
7

Edwards et al. (2009). National Healthcare Safety Network (NHSN) report: Data summary for 2006
through 2008, issued December 2009. Available at:
http://www.cdc.gov/nhsn/PDFs/dataStat/2009NHSNReport.PDF

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Appendix 1. Secondary Bloodstream Infection (BSI) Guide (not
applicable to Ventilator-associated Events)
What is the meaning of the statement “not related to infection at another site” in
relation to a positive blood culture?
The purpose of using the CDC/NHSN infection criteria is to identify and consistently
categorize infections that are healthcare-associated into major and specific infection sites
or types. Several of the criteria include the caveat that signs, symptoms, and/or laboratory
findings cannot be related to infection at another site. When assessing positive blood
cultures in particular, one must be sure that there is no other CDC-defined primary site of
HAI that may have seeded the bloodstream secondarily; otherwise the bloodstream
infection may be misclassified as a primary BSI or erroneously associated with the use of
a central line, i.e., called a CLABSI.
Below are listed several scenarios that may occur with guidance on how to distinguish
between the primary or secondary nature of a BSI, along with the definition of “matching
organisms”, and important notes and reporting instructions.
1. Blood and site-specific specimen cultures match for at least one organism: In a
patient suspected of having an infection, blood and a site-specific specimen are
collected for culture and both are positive for at least one matching organism. If the
site-specific culture is an element used to meet the infection site criterion, then the
BSI is considered secondary to that site-specific infection.
a. Example: Patient meets HAI criteria for a symptomatic urinary tract infection
(suprapubic tenderness and >105 CFU/ml of E. coli) and blood culture from
the same date grows E. coli. This is an HAI SUTI with a secondary BSI and
the reported organism is E. coli.
b. Example: Patient meets HAI criteria for a symptomatic urinary tract infection
(suprapubic tenderness and >105 CFU/ml of E. coli) and blood culture from
the same date grows E. coli and P. aeruginosa. This is an HAI SUTI with a
secondary BSI and the reported organisms are E. coli and P. aeruginosa, since
P. aeruginosa is a logical pathogen for this site of infection.
c. Example: Patient meets HAI criteria for a symptomatic urinary tract infection
(suprapubic tenderness and >105 CFU/ml of E. coli) and blood culture from
the same date grows E. coli and S. epidermidis. This is an HAI SUTI with a
secondary BSI and the reported organism is only E. coli, since the single
common commensal S. epidermidis positive blood culture by itself does not
meet BSI criteria.
2. Blood and site-specific specimen cultures do not match: There are two scenarios
that can occur when a patient suspected of having an infection has blood and a sitespecific specimen cultured but the organisms do not match.
a. If the site-specific culture is an element used to meet the infection site
criterion and the blood isolate is also an element used to meet another
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criterion at the same infection site, then the BSI is considered secondary to
that site-specific infection.
i. Example: Postoperative patient becomes febrile and complains of
nausea and abdominal pain. Blood and an aseptically-obtained T-tube
drainage specimen are collected for culture. A CT scan done that day
shows fluid collection suggestive of infection. Culture results show
Escherichia coli from the drainage specimen but the blood grows
Bacteroides fragilis. Because the patient meets IAB criteria by positive
site-specific culture (IAB criterion 3a) and by positive blood culture as
an element of a different criterion of the same infection site (IAB 3c),
the blood is considered a secondary BSI to an IAB and both organisms
would be listed as the IAB infection pathogens. No primary BSI would
be reported.
b. If the site-specific culture is an element used to meet the infection site
criterion and the blood isolate is not, then the BSI is considered a primary
infection.
i. Example: Postoperative patient has an intraabdominal abscess (IAB)
noted during reoperation and purulent material is obtained at that time
which grows Escherichia coli. The patient spikes a fever two days
later and blood culture shows Bacteroides fragilis. Because the
organisms from the site and blood cultures do not match, and no sitespecific criterion that includes positive blood culture as an element is
met, both a site-specific infection (IAB criteria 1 and 2) and a primary
BSI would be reported.
ii. Example: Unconscious ICU patient with a Foley catheter and central
line for past 4 days spikes a fever; blood, urine and sputum specimens
are collected for culture. The urine culture grows >100,000 CFU/ml of
Escherichia coli, blood culture grows Enterococcus faecium, and
sputum shows oral flora only. Because the organisms from the urine
and blood cultures do not match, and a UTI criterion that includes
positive blood culture as an element is not met, both a SUTI
(criterion 1a) and a primary BSI would be reported. This infection does
not meet the ABUTI criterion since that requires at least one matching
uropathogen organism in urine and blood in an asymptomatic patient.
3. No site-specific specimen culture, only a positive blood culture: In a patient
suspected of having an infection, if the only specimen cultured is blood and it grows a
logical pathogen for the suspected body site of infection, and a site-specific infection
criterion is met, an element of which may or may not include a positive blood culture,
the BSI is considered secondary to that site-specific infection.
a. Example: Postoperative patient has an abscess in the small bowel noted during
reoperation. The only specimen cultured is blood which grows B. fragilis.
Because gastrointestinal tract infection (GIT) criterion 1 is met with the
surgically-identified abscess alone and because B. fragilis is a logical
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pathogen for this site of infection, the BSI is considered secondary to a GIT
and B. fragilis is listed as the GIT infection pathogen.
b. Example: Patient has a positive blood culture with E. coli proximal in time
with fever, abdominal pain, and CT scan evidence of intraabdominal abscess
(IAB). This patient meets IAB criterion 3c, which includes a positive blood
culture as one of its elements. The BSI is considered secondary to the IAB and
E. coli is listed as the IAB infection pathogen.
4. Negative site-specific specimen culture with positive blood culture: In a patient
suspected of having an infection, if a specimen from the suspected site of infection is
cultured and yields no growth, but a blood specimen collected as part of the infection
work-up is positive, that BSI is only considered a secondary BSI if another of the sitespecific criteria that includes positive blood culture as an element is met. Otherwise,
the BSI is considered a primary BSI, even if another criterion for that site is met and
the blood isolate is a logical pathogen for the infection.
a. Example: Patient has purulent material from the IAB space cultured and it
yields no growth. The patient also has fever, abdominal pain, a positive blood
culture with Pseudomonas aeruginosa, and radiographic evidence of IAB
infection. This patient does not meet IAB criterion 1 (positive culture from
purulent material) but does meet IAB criterion 3c, an element of which is a
positive blood culture (signs/symptoms plus positive blood culture plus
radiographic evidence). This BSI is considered secondary to the IAB and P.
aeruginosa is listed as the IAB infection pathogen.
b. Example: Postoperative knee replacement patient with a central line spikes a
fever; blood and knee joint fluid are cultured. Only the blood cultures from at
least two separate blood draws are positive for S. epidermidis. No other JNT
infection criteria are met. This BSI should be reported as a CLABSI.
c. Example: Patient has a central line in place for 10 days. Patient complains of
knee joint tenderness and limited range of motion. CT scan findings suggest
joint (JNT) infection but culture of a needle-aspirated joint fluid is negative.
However, a blood culture from the same time period grows S. aureus. This
patient does not meet JNT criterion 1 (positive joint fluid culture) but does
meet JNT criterion 3d (signs/symptoms plus imaging test evidence of
infection). Even though S. aureus is a logical pathogen for this infection site,
it is also a likely pathogen for a CLABSI. This BSI should be reported as a
CLABSI, not a secondary BSI. So in this example, both a JNT infection and a
CLABSI are reported.
A matching organism is defined as one of the following:
1. If genus and species are identified in both cultures, they must be the same.
a. Example: A blood culture reported as Enterobacter cloacae and an
intraabdominal specimen of Enterobacter cloacae are matching organisms.
b. Example: A blood culture reported as Enterobacter cloacae and an
intraabdominal specimen of Enterobacter aerogenes are NOT matching
organisms as the species are different.
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2. If the organism is less definitively identified in one culture than the other, the
identifications must be complementary.
a. Example: A surgical wound growing Pseudomonas spp. and a blood culture
growing Pseudomonas aeruginosa are considered a match at the genus level
and therefore the BSI is reported as secondary to the SSI.
b. Example: A blood culture reported as Candida albicans and a urine culture
reported as yeast are considered to have matching organisms.
Notes:
1. If the blood isolate by itself does not meet BSI criteria (e.g., only one positive blood
culture of a common commensal), then that isolate may not be used to indicate the
presence of a secondary BSI (see example 1c).
2. Antibiograms of the blood and potential primary site isolates do not have to match.
3. Blood and site-specific specimens do not have to be collected on the same day but
their collection dates must be such that they are considered part of the diagnostic
work-up for the infection in question.
Reporting Instructions:
1. For reporting secondary BSI for possible and probable VAP, see Chapter 10.
2. Do not report secondary bloodstream infection for vascular (VASC) infections,
clinically-defined pneumonia (PNU1), Ventilator-Associated Conditions (VAC), or
Infection-related Ventilator-Associated Complications (IVAC).
3. If a site-specific criterion requiring positive culture results is met, be sure to check the
positive culture box when specifying the criteria used when adding the event, even if
another criterion that does not include culture results is also met. For example, using
the scenario in 2.a.i above, the following boxes for criteria used would be checked
when entering the SSI into the NHSN application: fever, nausea, pain or tenderness,
positive culture, positive blood culture, imaging test evidence of infection.

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