Bacteremia Due to Extended-Spectrum-β-Lactamase-Producing Aeromonas spp. at a Medical Center in Southern Taiwan

Abstract

ABSTRACTAlthough extended-spectrum-β-lactamase (ESBL)-producing aeromonads have been increasingly reported in recent years, most of them were isolates from case reports or environmental isolates. To investigate the prevalence of ESBL producers amongAeromonasblood isolates and the genes encoding ESBLs, consecutive nonduplicateAeromonasblood isolates collected at a medical center in southern Taiwan from March 2004 to December 2008 were studied. The ESBL phenotypes were examined by clavulanate combination disk test and the cefepime-clavulanate ESBL Etest. The presence of ESBL-encoding genes, includingblaTEM,blaPER,blaCTX-M, andblaSHVgenes, was evaluated by PCR and sequence analysis. The results showed that 4 (2.6%) of 156Aeromonasblood isolates, 1Aeromonas hydrophilaisolate and 3Aeromonas caviaeisolates, expressed an ESBL-producing phenotype. The ESBL gene in twoA. caviaeisolates wasblaPER-3, which was located in both chromosomes and plasmids, as demonstrated by Southern hybridization. Of four patients with ESBL-producingAeromonasbacteremia, two presented with catheter-related phlebitis and the other two with primary bacteremia. Three patients had been treated with initial noncarbapenem β-lactams for 5 to 10 days, and all survived. In conclusion, ESBL producers exist amongAeromonasblood isolates, and clinical suspicion of ESBL production should be raised in treating infections due to cefotaxime-resistantAeromonasisolates.