Résumé
Genes encoding the quinolones resistance determining regions (QRDRs) in Streptococcus pneumoniae were detected by PCR and the sequence analysis was carried out to identify point mutations within these regions. The study was carried out to observe mutation patterns among S. pneumoniae strains in Malaysia. Antimicrobial susceptibility testing of 100 isolates was determined against various antibiotics, out of which 56 strains were categorised to have reduced susceptibility to ciprofloxacin (>or=2 microg/mL). These strains were subjected to PCR amplification for presence of the gyrA, parC , gyrB and parE genes. Eight representative strains with various susceptibilities to fluoroquinolones were sequenced. Two out of the eight isolates that were sequenced were shown to have a point mutation in the gyrA gene at position Ser81. The detection of mutation at codon Ser81 of the gyrA gene suggested the potential of developing fluoroquinolone resistance among S. pneumoniae isolates in Malaysia. However, further experimental work is required to confirm the involvement of this mutation in the development of fluoroquinolone resistance in Malaysia.
Sujets)
Substitution d'acide aminé/génétique , Antibactériens/pharmacologie , Protéines bactériennes/génétique , DNA gyrase/génétique , DNA topoisomerase IV/génétique , ADN bactérien/composition chimique , Résistance bactérienne aux médicaments/génétique , Humains , Malaisie , Tests de sensibilité microbienne , Mutation faux-sens , Infections à pneumocoques/microbiologie , Mutation ponctuelle , Réaction de polymérisation en chaîne , Quinolinone/pharmacologie , Analyse de séquence d'ADN , Streptococcus pneumoniae/effets des médicaments et des substances chimiquesRésumé
Fluorescent in situ hybridization (FISH) was carried out using two different oligonucleotide probes specific for Pseudomonas spp. and Acinetobacter spp. These probes were tested against different organisms and were found to be highly specific. Sensitivity testing showed that the probes were able to detect as low as 10 3 CFU/mL. In addition, FISH was carried out directly on positive blood culture samples and the detection of microorganisms took less than 2 h. We believe that FISH is a rapid method that can be used as a routine laboratory diagnostic technique for the detection of Acinetobacter spp. and Pseudomonas spp. in clinical samples.
Sujets)
Acinetobacter/génétique , Infections à Acinetobacter/microbiologie , Bactériémie/microbiologie , Techniques bactériologiques/méthodes , Sang/microbiologie , Humains , Hybridation fluorescente in situ/méthodes , Pseudomonas/génétique , Infections à Pseudomonas/microbiologie , Sensibilité et spécificitéRésumé
Escherichia coli isolates resistant to ceftazidime isolated in the University Malaya Medical Center (UMMC) Kuala Lumpur, Malaysia, between the years 1998 and 2000 were studied for extended-spectrum beta-lactamase (ESBL) production. All strains were analysed phenotypically and genotypically and found to be ESBL-producing organisms harbouring SHV-5 beta-lactamase. This was confirmed by PCR-SSCP and nucleotide sequencing of the blaSHV amplified gene. As there was no evidence of ESBL activity in E. coli prior to this, coupled with the fact that there was a predominance of SHV-5 beta-lactamases in Klebsiella pneumoniae isolates in UMMC, we postulate that the E. coli obtained the SHV-5 beta-lactamase genes by plasmid transfer from the ESBL-producing K. pneumoniae.