Analysis of genotypes and antimicrobial resistance of metallo-beta-lactamase-producing Pseudomonas aeruginosa of Yantai area

Objective To study the genotypes,antimicrobial resistance and the homology of metallo-β-lactamase(MBL)-producing Pseudomonas aeruginosa isolated from clinical specimens in Yantai area,so as to provide basis for reasonable selection of antibiotics and monitoring of the prevalence of metallo-beta-lactamase-producing strains.Methods Metallo-β-lactamase positive strains were screened from imipenem-resistant and ceftazidime-resistant pseudomonas aeruginosa isolates by E-test strips method and EDTA-IMP disk diffusion method;PCR was performed to amplify the resistant genes of imp,vim,spm and gim.Microdilution test were used to determine the MICs of 8 antibiotics; the homology among different strains was tested by enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) method.Results Among 42 strains,there were 18 strains screened with EDTA-IMP disk diffusion method,15 strains with E-test,12 strains with PCR,including 4 strains with specific bands of imp and 8 strains with vim bands.The metallo-β-lactamase-producing strains were multidrug resistant,and the PCR positive strains were highly resistant.Results of ERIC-PCR genotyping showed that there were seven PCR patterns among 18 strains screened by EDTA-IMP disk diffusion method,and 10 strains were in the same pattern.Conclusion EDTA-IMP disk diffusion method may be the first choice to screen MBL producing strains in Pseudomonas aeruginosa because of its economy, convenience and quickness.The major MBL genetype of Pseudomonas aeruginosa isolates is vim in Yantai area;the isolates are sensitive to amikacin and ciprofloxacin.The MBL producing strains in Pseudomonas aeruginosa appeared an outbreak in a certain hospital.