Surveillance culture for multidrug-resistant gram-negative bacteria: Performance in liver transplant recipients

Abstract

Background: The prevalence of infection with multidrug-resistant gram-negative bacteria (MDR-GNB) after solid-organ transplantation is increasing. Surveillance culture (SC) seems to be an important tool for MDR-GNB control. The goal of this study was to analyze the performance of SC for MDR-GNB among liver transplant (LT) recipients.

Methods: This was a prospective cohort study involving patients who underwent LT between November 2009 and November 2011. We screened patients for extended spectrum β-lactamase-producing Escherichia coli, extended spectrum β-lactamase-producing Klebsiella pneumoniae, and carbapenem-resistant Enterobacteriaceae, carbapenem-resistant Pseudomonas aeruginosa (CRPA), and carbapenem-resistant Acinetobacter baumannii (CRAB). We collected SC samples immediately before LT and weekly thereafter, until hospital discharge. Samples were collected from the inguinal-rectal area, axilla, and throat. The performance of SC was evaluated through analysis of its sensitivity, negative predictive value, and accuracy.

Results: During the study period, 181 patients were evaluated and 4,110 SC samples were collected. The GNB most often identified was CRAB, in 45.9% of patients, followed by CRKP in 40.3%. For all microorganisms, the positivity rate was highest among the inguinal-rectal samples. If only samples collected from this area were considered, the SC would fail to identify 34.9% of the cases of CRAB colonization. The sensitivity of SC for CRKP was 92.5%. The performance of SC was poorest for CRAB (sensitivity, 80.6%).

Conclusions: Our data indicate that SC is a sensitive tool to identify LT recipients colonized by MDR-GNB.

Keywords: Acinetobacter baumannii; Extended spectrum β-lactamase; Infection; Klebsiella pneumoniae; Pseudomonas aeruginosa; Risk factor for infection.