A prospective survey of Pseudomonas aeruginosa colonization and infection in the intensive care unit

Regev Cohen,Shoshana Cohen,Ronen Ben Ami,Maurice Shapiro,Svetlana Paikin,Amos Adler,Frida Babushkin,Martina Uda,Marina Afraimov,Efrat Khabra

doi:10.1186/s13756-016-0167-7

Abstract

BackgroundPseudomonas aeruginosa (PA) surveillance may improve empiric antimicrobial therapy, since colonizing strains frequently cause infections. This colonization may be ‘endogenous’ or ‘exogenous’, and the source determines infection control measures. We prospectively investigated the sources of PA, the clinical impact of PA colonization upon admission and the dynamics of colonization at different body sites throughout the intensive care unit stay.MethodsIntensive care patients were screened on admission and weekly from the pharynx, endotracheal aspirate, rectum and urine. Molecular typing was performed using Enterobacterial Repetitive Intergenic Consensus Polymerase Chain reaction (ERIC-PCR).ResultsBetween November 2014 and January 2015, 34 patients were included. Thirteen (38%) were colonized on admission, and were at a higher risk for PA-related clinical infection (Hazard Ratio = 14.6, p = 0.0002). Strains were often patient-specific, site-specific and site-persistent. Sixteen out of 17 (94%) clinical isolates were identical to strains found concurrently or previously on screening cultures from the same patient, and none were unique. Ventilator associated pneumonia-related strains were identical to endotracheal aspirates and pharynx screening (87–75% of cases). No clinical case was found among patients with repeated negative screening.ConclusionPA origin in this non-outbreak setting was mainly ‘endogenous’ and PA-strains were generally patient- and site-specific, especially in the gastrointestinal tract. While prediction of ventilator associated pneumonia-related PA-strain by screening was fair, the negative predictive value of screening was very high.

Highlights

Pseudomonas aeruginosa (PA) surveillance may improve empiric antimicrobial therapy, since colonizing strains frequently cause infections
The primary endpoint was the development of clinical infection due to PA, defined according to Centers for disease control and prevention (CDC)/The national healthcare safety network (NHSN) surveillance definitions of healthcare-associated infections [16] and American Thoracic Society criteria for ventilator-associated pneumonia (VAP) [17]
Secondary aims were identifying risk factors for PA colonization on admission and during Intensive care unit (ICU) stay, clonal analysis of strains at each body site during the ICU stay and the concordance between the strains related to infection and those detected on weekly screening

Summary

Introduction

Pseudomonas aeruginosa (PA) surveillance may improve empiric antimicrobial therapy, since colonizing strains frequently cause infections. This colonization may be ‘endogenous’ or ‘exogenous’, and the source determines infection control measures. We prospectively investigated the sources of PA, the clinical impact of PA colonization upon admission and the dynamics of colonization at different body sites throughout the intensive care unit stay. Pseudomonas aeruginosa (PA) is a leading cause of healthcare-associated infections in intensive care units (ICUs), mainly ventilator-associated pneumonia (VAP), central line-associated bloodstream infection (CLABSI) and surgical site infection (SSI). We studied the genetic relatedness of PA strains isolated from ventilated patients and hospital faucets. In the present study we aimed to prospectively determine the clinical impact of PA colonization on admission to the.

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