BİRGÜL KAÇMAZ, Özenç Fazilet ÇAKIR, Altan AKSOY

Hastane kaynaklı infeksiyonlardan izole edilen Escherichia coli, Klebsiella pneumoniae ve Klebsiella oxytoca türlerinde genişletilmiş spektrumlu beta-laktamaz saptanması

Çeşitli klinik örneklerden hastane infeksiyon etkeni olarak izole edilen Escherichia coli, Klebsiella pneumoniae ve Klebsiella oxytoca türlerinde genişletilmiş spektrumlu beta-laktamaz (GSBL) varlığı araştırılmıştır. GSBL üretimini saptamak için çift disk sinerji (ÇDS), disk difüzyon tarama vefenotipik doğrulama testleri kullanılmıştır. Fenotipik doğrulama testine göre diğer iki testin duyarlılık, özgüllük ve teşhis doğrulukları değerlendirilmiştir. incelenen bakterilerde % 66 oranında GSBL üretimi saptanmıştır. E.coli ve K.oxytoca'ya göre K.pneumoniae izolatlarında daha yüksek oranda GSBL üretimi bulunmuştur. ÇDS testinin duyarlılık, özgüllük ve teşhis doğrulukları sırasıyla % 82, % 85 ve % 83 oranında tespit edilmiştir. 1997'de yayınlanan NCCLS disk difüzyon değerlendirme kriterlerinin 1997'den önce yayınlanan kriterlere göre GSBL üretimini göstermede daha duyarlı olduğu saptanmıştır. En duyarlı indikatör antibiyotiğin seftazidim olduğu gösterilmiştir. Bununla birlikte disk difüzyon tarama testinde en az iki geniş spektrumlu beta-laktam kullanılmasıyla yanlış negatiflik oranlarının azalacağı sonucuna varılmıştır.

Anahtar Kelimeler:

Disk difüzyon antimikrobiyal testleri, Duyarlılık ve özgüllük, Mikrobiyal duyarlılık testleri, Klebsiella pneumoniae, Klebsiella oxytoca, Escherichia coli, Çapraz enfeksiyon, beta-Laktamazlar

Detection of extended spectrum beta-lactamase production in Escherichia coli, Klebsiella pneumoniae and Klebsiella oxytoca strains isolated from nosocomial infections

The presence of extended spectrum beta-laktamase (ESBL) in the nosocomial isolates of Escherichia coli, Klebsiella pneumoniae ve Klebsiella oxytoca was investigated. To detect ESBL production, double-disk synergy (DDS), disk diffusion screening and phenotypical confirmation tests were used. The sensitivity, specificity and diagnostic reliability of the other two tests were evaluated according to phenotypical confirmation test results. There was 66 % ESBL production in the bacteria studied. In K.pneumoniae isolates, there was a higher rate of ESBL production than in E. coli and K. oxytoca isolates. The sensitivity, specificity and diagnostic reliability of DDS test were 82 %, 85 % and 83 %, respectively. NCCLS disk diffusion criteria published in 1997 were found to be more sensitive in revealing ESBL production than those published before 1997. Ceftazidime was shown to be the most sensitive indicator antibiotic. In addition, it was concluded that by the use of at least two wide-spectrum beta-lactams in disk diffusion screening test, the rate of false negativity could be decreased.

Keywords:

Disk Diffusion Antimicrobial Tests, Sensitivity and Specificity, Microbial Sensitivity Tests, Klebsiella pneumoniae, Klebsiella oxytoca, Escherichia coli, Cross Infection, beta-Lactamases,

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