First report of VIM metallo-β-lactamase production in Escherichia coli and Klebsiella pneumoniae clinical isolates from Gaza Strip, Palestine

Introduction: Even though the increasing incidence of VIM-producing E. coli and K. pneumoniae has been reported worldwide, studies are still lacking in Palestine. The aim of this study was to screen carbapenem-resistant E. coli and K. pneumoniae bacteria in the Gaza Strip, Palestine and further to characterize carbapenemase-producing isolates. Methods: A total of 69 E. coli and 27 K. pneumoniae isolates were obtained from three Gaza hospitals and recovered from urine, wound swabs, blood and ear discharge. The screening for metallo-β-lactamases (MBLs) was performed by using the imipenem-EDTA disc synergy test. The detection of β-lactamases genes, detection of non-β-lactam genes and the characterization of integrons were performed by PCR and sequencing. The clonal relationship among the isolates was determined by pulsed-field gel electrophoresis (PFGE). Results: Our study showed that 4 E. coli (5.8%) and 5 K. pneumoniae (18.5%) were positive by the imipenem-EDTA disc synergy test. BlaVIM-4 was detected in six isolates and blaVIM-28 was identified in three isolates. The β-lactamases genes in the VIM-producing K. pneumoniae isolates were blaCTX-M-15 (n=3), blaCTX-M-14 (n=1), blaSHV-1 (n=3), blaSHV-12 (n=1), blaTEM-1 (n=1) and blaOXA-1 (n=1). Aac(6')-Ib-cr gene was confirmed in four E. coli and in two K. pneumoniae isolates. QnrS1 was identified in two K. pneumoniae isolates. The class 1 integron was identified with the different gene cassette; dfrA17-aadA5, dfrA5, dfrA12-orf-aadA2 and dfrA17-aadA5 were identified. Conclusions: Our study indicated for the first time the emergence of multidrug-resistant VIM-containing K. pneumoniae and E. coli isolates of clinical origin in Gaza Strip hospitals.