RESUMEN
Background: Pseudomonas aeruginosa plays an important role in opportunistic and nosocomial infections affecting individuals with predisposing conditions
Methods: In this respect, we evaluated the production of MBLs among 100 clinical isolates of Pseudomonas aeruginosa sources in Mansoura University Hospitals
Results: Most isolates were highly resistant to penicillins and cephalosporins. On the other hand, most strains were sensitive to imipenem as 91% of the isolates were susceptible. The effect of MBL inhibitors using a simple disk diffusion test revealed the efficiency of EDTA and 2-mercaptoethanol as Metalo-beta-lactamase inhibitors due the observed expansion of the growth-inhibitory zone of the two inhibitors. Cupric chloride also gave a clear result, but with a weak inhibitory effect. IMP and VIM genes were amplified from both genomic and plasmid DNA extracted from 26 isolates. The amplification primers of both markers were specifically designed to amplify 600 bp for IMP and 500 bp for VIM. On the other hand, two isolates did not harbor IMP gene on their plasmids while six isolates did not contain VIM on their plasmids. Subsequent sequencing of the generated amplicons showed different types of mutation in the sequenced regions of the tested resistance genetic markers. They include insertion, deletion and substitution mutations. Moreover, the region 178-822 of IMP and the region 111-627 of VIM, commonly found in resistant Pseudomonas aeruginosa, are the most predominant variable regions
Conclusion: particular PCR and subsequent sequencing provide a useful tool for accurate and cost efficient characterization of MBLs producing Pseudomonas aeruginosa isolates. The accuracy of the sequencing method can answer the epidemiological questions that can't be answered by the traditional microbiological methods. This approach will help in choosing the best effective antibiotic to overcome the nosocomial infection