Antimicrobial resistance in nosocomial bloodstream infection associated with pneumonia and the value of systematic surveillance cultures in an adult intensive care unit.
OBJECTIVE
To study the occurrence of multiple-drug-resistant pathogens in nosocomial bloodstream infection associated with pneumonia. To evaluate prediction of multiple drug resistance by systematic surveillance cultures.


METHODS
A retrospective study of a prospectively gathered cohort.


METHODS
Fifty-four-bed adult medical-surgical intensive care unit of a tertiary hospital.


METHODS
One hundred twelve intensive care unit patients with nosocomial bloodstream infection associated with pneumonia from 1992 through 2001.


METHODS
None.


RESULTS
Concordance of blood cultures with prior surveillance culture was assessed. Surveillance cultures were taken routinely as thrice weekly urinary cultures and oral swabs, once weekly anal swabs, and thrice weekly tracheal aspirates in intubated patients. Tracheal surveillance cultures from 48 to 96 hrs before bloodstream infection and surveillance cultures from any site during the same intensive care unit episode but >or=48 hrs before bloodstream infection were evaluated separately. Forty-four bloodstream infections (39%) were caused by a multiple-drug-resistant pathogen. Multiple-drug-resistant pathogens were predicted by tracheal surveillance culture in 70% (concordant); in 15%, tracheal surveillance culture grew a multiple-drug-resistant pathogen not found in blood cultures (discordant). Multiple-drug-resistant pathogens were predicted by any surveillance culture in 88%, but these surveillance cultures grew additional multiple-drug-resistant pathogens not causing bloodstream infection in up to 46% of patients. In 86% of bloodstream infections, early (i.e., within 48 hrs) antibiotic therapy was appropriate. Patients were divided into four risk categories for multiple-drug-resistant bloodstream infection based on length of prior intensive care unit stay and prior antibiotic exposure. In patients with two risk factors, knowledge of surveillance cultures increased appropriateness of early antibiotic therapy from 75-79% to 90% (p<.05) while limiting use of broad-spectrum antibiotics such as antipseudomonal betalactams, fluoroquinolones, and carbapenems.


CONCLUSIONS
In our intensive care unit, tracheal surveillance culture predicted multiple-drug-resistant etiology of bloodstream infection associated with pneumonia in 70% of patients but yielded discordant resistant pathogens in 15%. In the subgroup of patients with two risk factors for multiple-drug-resistant infection, incorporating results of surveillance cultures moderately contributed to adequacy of early antibiotic therapy while limiting antibiotic consumption.
Depuydt
Pieter O
PO
Department of Intensive Care, Ghent University Hospital, Gent, Belgium. pieter.depuydt@ugent.be
Blot
Stijn I
SI
Benoit
Dominique D
DD
Claeys
Geert W
GW
Verschraegen
Gerda L
GL
Vandewoude
Koenraad H
KH
Vogelaers
Dirk P
DP
Decruyenaere
Johan M
JM
Colardyn
Francis A
FA
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D001431:Bacteriological Techniques; D001530:Belgium / Q000453:epidemiology; D003428:Cross Infection / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D018432:Drug Resistance, Multiple; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D011159:Population Surveillance; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018709:Statistics, Nonparametric
D000900:Anti-Bacterial Agents