RESUMO
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
RESUMO
Background: Klebsiella species cause 3-7% of all nosocomial infections, placing them in the top 10 of nosocomial bacterial pathogens
Materials: In this respect, we evaluated the differences in some quinolone resistance determinants among 70 clinical isolates of Klebsiella pneumoniae collected from Mansoura University Hospitals
Results: In the present investigation, some molecular typing techniques were applied on 70 isolates of K. pneumoniae isolated from Mansoura University Hospitals from different clinical lesions. The distribution of antibiotic resistance among the isolated strains showed high incidence of resistance to extended-spectrum cephalosporins [70 to 94.29%] and to quinolones [38.57 to 55.7 %] was also observed. Imipenem was the most active antibiotic so; it could be considered the drug of choice for treatment of infections caused by multi-resistant K. pneumoniae. Plasmid profiles of the tested strains appear to be diverse, although some similarities were found among tested strains. Sixty seven out of 70 strains contained plasmid DNA. PCR amplification was used to detect some quinolone resistance determinant genes such as gyrA, gyrB and Onr in the collected Klebsiella pneumoniae isolates. Using pyrosequencing technique, the sequenced region of gyrA gene was able to differentiate between resistant and sensitive strains however, the sequenced region of gyrB gene failed to differentiate between resistant and sensitive strains. Qnr gene was detected in all tested strains except strains No. 24 and 28
Conclusion: Using PCR and DNA sequencing of the target region of gyrA gene, we were able to differentiate between resistant and sensitive strains. While, amplification of another region of gyrB or Qnr genes failed to differentiate between the isolates. But, it could detect different types of mutations between the clinical isolates