| Very little is known about the occurrence and various types of extended-spectrum b-lactamase
(ESBL), AmpC and carbapenemase in Iran. The aims of this study were to determine the
prevalence of ESBLs, AmpCs and carbapenemase genes among Enterobacteriaceae in
Azerbaijan and to characterize the genetic composition of the detected genes. A total of 307
Enterobacteriaceae isolates, recovered from five medical centres, were screened for ESBL,
AmpC and carbapenemase activities by the disc diffusion method and phenotypic confirmatory
tests. The 162 selected strains (third-generation cephalosporins, cefoxitin- or carbapenemresistant
strains with positive or negative phenotypic confirmatory tests) were selected for
multiplex PCR screening for b-lactamase genes, and detected genes were confirmed by
sequencing. Of 162 isolates, 156 harboured 1 to 6 b-lactamase genes of 41 types. The most
prevalent genes were blaTEM-1 (29.9 %), followed by blaCTX-M-15 (25.7 %). Plasmid-mediated
AmpC was detected in 66 strains (21.5 %) alone or in combination with other genes.
Carbapenemase-encoding genes were detected in 18 strains (5.8 %) of 27 carbapenem-nonsusceptible
isolates including 11, 7, 3 and 1 cases of blaOXA-48, blaNDM-1, blaKPC-2 and blaKPC-3
genes, respectively. Interestingly, 148 (94.8 %) of 156 strains with any b-lactamase gene were
found to have a multidrug-resistant pattern. The rate of resistance to b-lactams and multidrugresistant
Enterobacteriaceae is high in Azerbaijan. All positive strains for carbapenemase genes
were resistant to all b-lactams. The present study reveals the high occurrence of CTX-M-type
ESBLs followed by TEM and SHV variants among Enterobacteriaceae isolates. East Azerbaijan
seems to be an alarming focus for OXA-48, NDM-1 and KPC dissemination. |