[Investigation of phenotypic and genotypic characteristics of vancomycin-resistant Enterococcus faecium isolates]. / Vankomisine dirençli Enterococcus faecium suslarinin fenotipik ve genotipik olarak incelenmesi.

The purpose of the present study was to investigate the phenotypic and genotypic characteristics and the probable clonal dissemination of 13 vancomycin-resistant enterococcus (VRE) strains isolated between February-August 2006 from 11 patients at the Hospital of Istanbul Faculty of Medicine. The in vitro activities of antibiotics were determined by disk diffusion method in accordance with the CLSI (Clinical and Laboratory Standards Institute) guidelines and the minimum inhibitory concentration (MIC) values by E-test. Multiplex polymerase chain reaction (PCR) was performed for detection of vanA, vanB and vanC genes and RAPD-PCR (Randomly amplified polymorphic DNA-PCR) for investigating a clonal relationship among the isolates. All isolates exhibited resistance to vancomycin, teicoplanin, ampicillin, and high-level resistance to streptomycin. VanA phenotype and the relevant vanA gene, characterised by resistance to both vancomycin and teicoplanin, were detected in all isolates which were all E. faecium. Molecular investigation by RAPD-PCR showed these strains to belong to four different patterns, each containing 1 to 5 isolates. According to these results, the spread of VRE within our hospital was considered as a polyclonal dissemination.

[Detection of CTX-M-15 type extended spectrum beta-lactamase in an Escherichia coli strain isolated from the urine sample of a hospitalized patient]. / Hastanede yatan bir hastanin idrar örneginden izole edilen Escherichia coli susunda CTX-M-15 tipi genislemis spektrumlu beta-laktamazin tanimlanmasi.

In this study, a CTX-M type extended spectrum beta-lactamase (ESBL) enzyme has been detected in a multiresistant Escherichia coli strain which was isolated from the urine sample of a hospitalized patient. Minimum inhibitor concentrations (MIC) of the tested antibiotics were determined by the agar dilution technique according to the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS) guidelines. The isolate was found to be sensitive to imipinem, moderately susceptible to chloramphenicol and resistant to ceftazidime, cefotaxime, aztreonam, ciprofloxacin, tobramycin, tetracycline and trimethoprim/sulphamethoxazole. Ceftazidime/ceftazidime-clavulanic acid and cefotaxime/cefotaxime-clavulanic acid rates were found as >8 and the results were accepted as positive for an ESBL. The MIC of cefotaxime (256 microg/ml) was found four fold higher than that of ceftazidime (64 microg/ml) and the production of a CTX-M- type ESBL was investigated in the strain. Cefotaxime resistance, together with tobramycin and tetracycline resistance, was transferred to the recipient strain by conjugation. The pl's of the culture extracts of the isolate were found as 5.4, 7.5 and 9.1 by isoelectric focusing (IEF) method, but cefotaxime was hydrolysed only by the beta-lactamase focusing at a pl of 9.1 in the following bioassay. The bla-gene was amplified with the CTX-M group specific primers and sequencing of the polymerase chain reaction (PCR) product proved the enzyme to be CTX-M-15. This isolate was also found to harbor TEM- and SHV-type and OXA-10-like ESBLs, by IEF and PCR.

Moxifloxacin activity against clinical isolates compared with the activity of ciprofloxacin.

The activity of moxifloxacin, a new 8-methoxyquinolone, was compared in vitro with the activity of ciprofloxacin against clinical strains isolated from various sites of infection. The mode MIC values of moxifloxacin were superior to those of ciprofloxacin against Streptococcus pneumoniae, methicillin-susceptible and -resistant Staphylococcus aureus, Enterococcus spp., Escherichia coli and Acinetobacter spp., while ciprofloxacin was more active against Klebsiella pneumoniae and Pseudomonas spp. Both antibiotics had similar activity against Haemophilus influenzae, Moraxella catarrhalis and Enterobacter spp.