engleski

Antimicrobial susceptibility and characterization of metallo-β-lactamases, extended-spectrum β- lactamases, and carbapenemases of Bacillus cereus isolates

The susceptibility of 66 clinical and environmental B. cereus isolates were tested to selected antimicrobials by a broth microdilution method. All strains were resistant to β-lactams and susceptible to gentamicin and imipenem. Sixty- five (98.5 %) isolates were susceptible to meropenem and ciprofloxacin and 74.2 % to azithromycin. Significant differences in MIC values between environmental and clinical isolates were not demonstrated (p>0.05). According to the disc diffusion method, 80.3 % to 98.5 % of the strains were resistant to one or more of four cephalosporins. The presence of genes for B. cereus β-lactamases BCI, BCII, BCIII, extended- spectrum β-lactamases from the CTX and TEM family and the carbapenemases belonging to IMP and VIM family was studied. BlaII genes were expressed in all isolates ; the PCR products for blaIII were also detected in two strains, but none of them was positive for blaI. The amplicon of the family blaCTX-M, mostly M-1 and M-15, was confirmed among 68.2 % of the isolates, while were blaVIM-like genes determined in 21.2 % of the samples.

Bacillus cereus ; carbapenemases ; extended-spectrum beta-lactamases

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