2024年5月28日发(作者：)

Surveillance Definitions

CDC/NHSN Surveillance Definitions for Specific Types of

Infections

INTRODUCTION

This chapter contains the CDC/NHSN surveillance definitions and criteria for all specific types of

infections. This chapter also provides additional required criteria for the specific infection types that

constitute organ space surgical site infections (SSI) ( for example, mediastinitis [MED] that may follow

a coronary artery bypass graft, intra-abdominal abscess [IAB] after colon surgery, etc.). Comments

and reporting instructions that follow the site-specific criteria provide further explanation and

are integral to the correct application of the criteria. Refer to Chapter 2 (Identifying HAIs in

NHSN) for specific guidance for making HAI determinations.

Infection criteria contained in this chapter may be necessary for determining whether a positive blood

specimen represents a primary bloodstream infection (BSI) or is secondary to a different type of

infection (see Appendix B Secondary Bloodstream Infection (BSI) Guide). A BSI that is identified as

secondary to another site of infection must meet one of the infection criteria detailed in this chapter and

meet other requirements. Secondary BSIs are not reported as Laboratory Confirmed Bloodstream

Infections in NHSN, nor can they be associated with the use of a central line.

NOTES:

 See individual protocol chapters for infection criteria for urinary tract infections (UTI),

bloodstream infections (BSI), pneumonia (PNEU), ventilator-associated infections (VAE), and

surgical site infections (SSI).

 Organisms belonging to the following genera cannot be used to meet any NHSN definition:

Blastomyces, Histoplasma, Coccidioides, Paracoccidioides, Cryptococcus and Pneumocystis.

These organisms are typically causes of community-associated infections and are rarely known

to cause healthcare-associated infections, and therefore are excluded.

 Antibiograms of the blood and isolates from potential primary sites of infection do not have to

match for purposes of determining the source of BSIs (see “matching organisms” below).

 A matching organism is defined as one of the following:

1. If genus and species are identified in both specimens, they must be the same.

a. Example: An intraabdominal specimen is used as an element to meet IAB

definition and is growing Enterobacter cloacae. A blood specimen with a

collection date in the IAB secondary BSI attribution period is reported to

be growing Enterobacter cloacae. These are considered matching

organisms.

b. Example: An intraabdominal specimen is used as an element to meet IAB

definition and is growing Enterobacter aerogenes. A blood specimen with

a collection date in the IAB secondary BSI attribution period is reported to

be growing Enterobacter cloacae. These are NOT considered matching

organisms as the species are different.

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January 2018

Surveillance Definitions

2. If the organism is less definitively identified in one specimen than the other, the

lesser identified organism must be identified to at least the genus level and at that level

the organisms must be the same.

a. Example: A surgical wound growing Pseudomonas species is used to

meet deep incisional SSI criteria and a blood specimen growing

Pseudomonas aeruginosa is collected in the SSI secondary BSI attribution

period. The organisms are considered matching at the genus level and

therefore the BSI is secondary to the SSI.

b. Example: PCR identifying Enterococcus faecalis in CSF meets the MEN

definition. A subsequent blood culture collected in the MEN secondary

BSI attribution period is identified as Enterococcus species. The organisms

are considered to be matching and therefore the BSI is secondary to MEN

3. There are two exceptions to the definition:

a. Infections meeting LCBI 2 criteria with staphylococcus or streptococcus

Example-(staphylococcus): A patient has a fever and a previous chest

tube site is reddened, swollen and a culture is collected from the soft

tissue. The chest tube site culture is reported positive for Staphylococcus

species. SST/ST definition is met. The next day 2 blood culture sets are

collected. The blood cultures are both positive for coagulase negative

Staphylococcus. The organisms are NOT considered matching, because

Staphylococcus species could represent a coagulase negative or a

coagulase positive Staphylococcus. Therefore the BSI would not be

considered secondary to SST/ST.

Example-(streptococcus): A patient has a fever and a previous chest tube

is reddened swollen and a culture is collected from the soft tissue. The

chest tube site culture is reported positive for Streptococcus species.

SST/ST definition is met. The next day 2 blood culture sets are collected.

The blood cultures are both positive for Streptococcus, viridans group.

The organisms are NOT considered matching, because Streptococcus

species could represent a Streptococcus, viridans group or non-

Streptococcus, viridans group. Therefore the BSI would not be considered

secondary to SST/ST.

b. In cases where an organism is identified only as “yeast” or “yeast not

otherwise specified”, the organism can be considered a match to other

yeasts, when collected during the required timeframe, whether more fully

identified or not.

Example: A culture of tissue from ulcer margin of a decubiti reported

positive for yeast is used as an element to meet DECU definition. A blood

specimen collected in the secondary BSI attribution period of the DECU is

reported as Candida albicans. In this example the two organisms are

considered matching organisms as the organisms are complementary

(specifically, Candida is a type of yeast) and because yeasts isolated from

non-sterile sites are commonly not identified to the genus or genus and

species level.

NOTE: This exception is limited to yeast. It does not apply to

identification of organisms as Gram positive cocci, Gram negative

rods, etc.

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