Çeşitli klinik örneklerden izole edilen Escherichia coli ve Klebsiella pneumoniae suşlarında plazmid aracılı AmpC tipi beta-laktamaz varlığının fenotipik olarak araştırılması
Küçük Resim Yok
Tarih
2013
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Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Beta-laktamaz enzimlerinin sentezi, Gram negatif bakterilerde görülen direnç mekanizmalarının en sık nedenlerindendir. AmpC tipi beta-laktamaz genlerinin plazmidler aracılığı ile diğer bakterilere aktarılması ve sıklığının artmasına bağlı olarak hastane epidemilerine yol açması klinik açıdan önemli bir sorundur. Bu çalışmanın amacı 2010-2011 yıllarında çeşitli klinik örneklerden izole edilen sefoksitin orta duyarlı veya dirençli Escherichia coli ve Klebsiella pneumoniae suşlarında plazmidik AmpC (pAmpC) tipi beta-laktamaz varlığının fenotipik yöntemlerle araştırılmasıdır. Çalışmada pAmpC tipi beta-laktamaz varlığını araştırmak için; Kirby-Bauer disk difüzyon yöntemiyle CLSInın Enterobacteriaceae için önerdiği zon çapı değerleri doğrultusunda sefoksitin (30 ?g) direnci incelenmiştir. Sefoksitine dirençli ( 14 mm) ve orta duyarlı (15-17 mm) olan suşlarda pAmpC beta-laktamaz varlığının araştırılması için, kombine disk testi ve Modifiye Hodge Testi (MHT) yapılmıştır. Kombine disk testi veya MHT ile pozitif bulunan suşlara sefotetan kloksasilin stripleri ile E-test (AB Biodisk, İsveç) yapılmış ve sefotetan kloksasilin MİK değeri kloksasilinsiz tarafa göre 8 kat azalma görülen suşlarda pAmpC varlığı fenotipik olarak doğrulanmıştır. Çalışmaya dahil edilen sefoksitine dirençli 42 E.coli suşundan dokuzunda MHT ile, sekizinde kombine disk testi ile AmpC beta-laktamaz pozitif bulunmuştur. Kombine disk testi ile pozitif olan sekiz E.coli suşu E-test ile de pozitif olarak saptanmıştır. MHT ile pAmpC beta-laktamaz pozitif bulunan bir E.coli suşu kombine disk testi ve E-test ile negatif olarak saptanmıştır. K.pneumoniae suşlarında ise pAmpC pozitifliği saptanmamıştır. Sonuç olarak, beta-laktam antibiyotiklerin sık kullanıldığı ülkemizde, pAmpC tipi beta-laktamaz yaygınlığının saptanması, bu dirence sahip etkenlerle oluşan infeksiyon hastalıklarının tedavisinde uygun ampirik tedavinin başlanmasında ve epidemiyolojik veri oluşturulmasında önemlidir. pAmpC beta-laktamaz varlığının fenotipik olarak hızlı ve doğru olarak ortaya çıkarılması klinik açıdan doğru ve etkin tedavi rejimlerinin uygulanmasını sağlayacaktır.
Production of beta-lactamase enzymes is one of the most common causes of resistance mechanisms in Gram negative bacteria. Increased frequency, transfer to other bacteria by plasmids and ability to cause hospital epidemics of AmpC-type beta-lactamase genes, are serious clinical problems. The aim of this study is to investigate the presence of plasmidic AmpC (pAmpC) type beta-lactamase in cefoxitin-moderately susceptible or resistant Escherichia coli and Klebsiella pneumoniae strains isolated from various clinical specimens during 2010-2011. For screening pAmpC beta-lactamase, cefoxitin (30 mg) disk was used to investigate cefoxitin resistance by Kirby-Bauer disk diffusion method as recommended by CLSI. Combined disk test and modified Hodge test (MHT) were performed to investigate AmpC beta-lactamase among cefoxitin-resistant (≤ 14 mm) and moderately susceptible (15-17 mm) strains. E-test method using cefotetan ± cloxacillin strips (AB Biodisk, Sweden) was performed for strains considered indicative of pAmpC by combined disk test or MHT. Strains indicating a reduction of cefotetan MIC by ≥ 8 twofold dilutions in the presence of cloxacilline were confirmed phenotypically positive for AmpC. Out of 42 cefoxitin-resistant E.coli strains included in the study nine strains were by MHT and eight strains were by combined disk method positive for pAmpC beta-lactamase. Eight E.coli strains considered positive by combined disk test was also confirmed as positive by E-test method. One strain that was considered AmpC beta-lactamase-positive by MHT was negative by combined disk and E-test. None of the K.pneumoniae strains was identified as pAmpC beta-lactamase-positive. In conclusion, because beta-lactam antibiotics are used frequently in our country, detection of the prevalence of AmpC type beta-lactamase is essential for appropriate empiric therapy of infectious diseases caused by agents possessing this resistance mechanism, and for the constitution of epidemiological data. The phenotypic detection of pAmpC beta-lactamase quickly and accurately will ensure the implementation of correct and effective treatment regimens.
Production of beta-lactamase enzymes is one of the most common causes of resistance mechanisms in Gram negative bacteria. Increased frequency, transfer to other bacteria by plasmids and ability to cause hospital epidemics of AmpC-type beta-lactamase genes, are serious clinical problems. The aim of this study is to investigate the presence of plasmidic AmpC (pAmpC) type beta-lactamase in cefoxitin-moderately susceptible or resistant Escherichia coli and Klebsiella pneumoniae strains isolated from various clinical specimens during 2010-2011. For screening pAmpC beta-lactamase, cefoxitin (30 mg) disk was used to investigate cefoxitin resistance by Kirby-Bauer disk diffusion method as recommended by CLSI. Combined disk test and modified Hodge test (MHT) were performed to investigate AmpC beta-lactamase among cefoxitin-resistant (≤ 14 mm) and moderately susceptible (15-17 mm) strains. E-test method using cefotetan ± cloxacillin strips (AB Biodisk, Sweden) was performed for strains considered indicative of pAmpC by combined disk test or MHT. Strains indicating a reduction of cefotetan MIC by ≥ 8 twofold dilutions in the presence of cloxacilline were confirmed phenotypically positive for AmpC. Out of 42 cefoxitin-resistant E.coli strains included in the study nine strains were by MHT and eight strains were by combined disk method positive for pAmpC beta-lactamase. Eight E.coli strains considered positive by combined disk test was also confirmed as positive by E-test method. One strain that was considered AmpC beta-lactamase-positive by MHT was negative by combined disk and E-test. None of the K.pneumoniae strains was identified as pAmpC beta-lactamase-positive. In conclusion, because beta-lactam antibiotics are used frequently in our country, detection of the prevalence of AmpC type beta-lactamase is essential for appropriate empiric therapy of infectious diseases caused by agents possessing this resistance mechanism, and for the constitution of epidemiological data. The phenotypic detection of pAmpC beta-lactamase quickly and accurately will ensure the implementation of correct and effective treatment regimens.
Açıklama
Anahtar Kelimeler
Farmakoloji ve Eczacılık
Kaynak
ANKEM Dergisi
WoS Q Değeri
Scopus Q Değeri
Cilt
27
Sayı
1
