Effect of carbapenem consumption patterns on the molecular epidemiology and carbapenem resistance of Acinetobacter baumannii.

Effect of carbapenem consumption patterns on the molecular epidemiology and carbapenem resistance of Acinetobacter baumannii.

J Med Microbiol. 2014 Sep 26;

Authors: Mózes J, Ebrahimi F, Gorácz O, Miszti C, Kardos G

Abstract
This study investigates the molecular epidemiology of Acinetobacter baumannii in the University of Debrecen in relation to antibiotic consumption. Overall and ward-specific antibiotic consumption was measured by the number of defined daily doses (DDD)/100 bed-days between 2002 and 2012; consumption was analysed against the number of A. baumannii positive patients/100 bed-days, number of isolates/positive samples and proportion of carbapenem resistant A. baumannii using time-series analysis. Altogether 160 A. baumannii isolates from different wards was collected and analysed. Carbapenemase genes blaOXA-23-like, blaOXA-24-like, blaOXA-48-like, blaOXA-51-like, blaOXA-58-like and integrons were sought for by PCR. Relatedness of isolates was assessed by pulsed-field gel electrophoresis. Prevalence and carbapenem resistance of A. baumannii was statistically associated with carbapenem consumption, prevalence data followed carbapenem usage with three quaterly lags (r=0.51-0.53, p<0.001); meropenem and ertapenem, but not imipenem usage affected prevalence. Colistin usage, in turn, lagged behind prevalence with one lag (r=0.68-0.70, p<0.001). Six clusters were identified; the neurology ward with the lowest carbapenem consumption was associated with the carbapenem susceptible cluster as well as with the carbapenem susceptible isolates in the cluster with variable susceptibility. Wards with high carbapenem usage almost exclusively harboured isolates from carbapenem resistant clusters. All clusters were dominated by isolates of one or two wards, but most wards were represented in multiple clusters. Increases in prevalence and carbapenem resistance of A. baumannii is associated with usage of meropenem and ertapenem but not of imipenem, which led to the spread of multiple clones in the University.

PMID: 25261064 [PubMed - as supplied by publisher]