[The frequency of PER-1 type extended spectrum beta-lactamases in nosocomial isolates of Pseudomonas aeruginosa]. / Hastane kaynakli Pseudomonas aeruginosa izolatlarinda PER-1 türü genislemis spektrumlu beta-laktamaz enzimlerinin sikligi.

The aim of this study was to determine the frequency of PER-1 type extended-spectrum beta-lactamase (ESBL) in nosocomial Pseudomonas aeruginosa strains isolated in Hacettepe University Adult Hospital. Sixty-seven non-duplicate P. aeruginosa isolates from patients with nosocomial infections between January 2002 and December 2004 were included in the study. The isolates were identified at species-level by Sceptor (Becton Dickinson, USA) system, and all the strains were stored at -80 degrees C until further testing. Polymerase chain reaction (PCR) was performed for the detection of (bla)PER-1 genes, and PFGE analysis was used to investigate their genetic relatedness. The antimicrobial susceptibilities of the PER-1 positive isolates were determined by Etest (AB Biodisk, Solna, Sweden) method. According to the results of PCR, 22.7% (15/67) of the isolates were positive for PER-1 enzyme. Those 15 (bla)PER-1 positive isolates showed eight different PFGE patterns, indicating the presence of multiple clones. Of the PER-1 positive P. aeruginosa isolates, nine were resistant to imipenem/meropenem, and 11 were resistant to piperacillin-tazobactam and tobramycin. The epidemiological investigation of multidrug resistant P. aeruginosa should give important clues for the initial empirical therapy, especially in certain geographic locations where ESBL-producing P. aeruginosa strains seemed to be highly prevalent.

[Molecular characterization of BRO beta-lactamases of Moraxella catarrhalis strains isolated from carrier children]. / Tasiyici çocuklardan izole edilen Moraxella catarrhalis suslarinda BRO beta-laktamazlarin moleküler tiplendirilmesi.

Nasopharyngeal carriage of Moraxella catarrhalis is a risk factor for upper respiratory tract infections and otitis media. In this study, we aimed to characterize BRO beta-lactamases of M. catarrhalis strains isolated from 64 children without any symptoms of respiratory disease. Gram negative diplococci grown on selective media and which are catalase, oxidase, DNase, nitrate reduction positive, glucose, maltose, sucrose and lactose fermentation negative, were diagnosed as M. catarrhalis. Antibiotic susceptibility testing was performed by agar dilution method recommended by NCCLS. BRO beta-lactamases were differentiated by restriction enzyme analysis method. The resistance rate for ampicillin was 18.8% and all the isolates were found to be sensitive to amoxicillin-clavulanate, cefazolin, cefaclor, azithromycin and ciprofloxacin. Out of 64 M. catarrhalis isolates, 57 (89%) were found beta-lactamase positive with nitrocefin disk test (Remel, USA). The presence of BRO beta-lactamases in these 57 strains (89%) was also confirmed by restriction enzyme analysis, while 7 (11%) of them were found to be negative. Among the positive strains, 47 (73.4%) were typed as BRO-1, and 10 (15.6%) were typed as BRO-2. The characterization of BRO beta-lactamases of M. catarrhalis strains in carrier children is important since the high rate of carriage predisposes to respiratory tract infections. As a result, BRO beta-lactamase typing will guide the treatment regimen against the respiratory infections that can occur due to M. catarrhalis in carrier children.