Çoklu antimikrobiyal dirençli escherichia coli'de genişlemiş spektrumlu β-laktamaz direncinin karakterizasyonu
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Date
2019-09-11
Authors
İbrahimli, Ulvi
Journal Title
Journal ISSN
Volume Title
Publisher
Bursa Uludağ Üniversitesi
Abstract
Bu araştırmanın amacı, çoklu antimikrobiyal dirençli (multidrug resistance: MDR) Escherichia coli'de (E. coli) geniş spektrumlu β-laktamaz (GSBL) üretiminin fenotipik ve genotipik yöntemlerle karakterize edilmesidir. Sağlıklı ve enfeksiyon bulgusu gösteren hayvanlardan 112 E. coli izolatı seçilerek araştırmaya dahil edildi. İzolatların antimikrobiyal direnç profillerini belirlemek amacıyla fenotipik tarama ve doğrulama testleri, broth-mikrodilüsyon ve disk difüzyon yöntemleri yapıldı. Genotipik testler ise PCR'la gerçekleştirildi. Antimikrobiyal duyarlılık çalışmalarında E. coli ATCC 25922 kontrol suşu olarak kullanıldı. Broth-mikrodilüsyon yöntemi ile seftazidim (CAZ) ve sefotaksimin (CTX) MİK değerleri ve disk difüzyon yöntemiyle ise bu ilaçların hem tek başına hem de klavulanik asit ilaçları ile kombinasyonlarının MİK değerleri CLSI'in (Clinical and Laboratory Standarts Institute) önerileri doğrultusunda değerlendirildi. Broth-mikrodilüsyon testi sonucuna göre 92 izolat (%82,14) seftazidime duyarlıyken 2 izolat (%1,78) orta duyarlı, 18 izolat (%16,07) ise dirençli olarak belirlendi. Sefotaksim için bu değerler sırasıyla 45 izolat (%40,17) duyarlı, 35 izolat (%31,25) orta duyarlı ve 32 izolat (%28,57) ise dirençli olarak belirlendi. Disk difüzyon yöntemi ile yapılan doğrulama testlerinde bir izolatın seftazidime (% 0.89) ve bir izolatın ise sefotaksime (% 0.89) dirençli olduğu tespit edildi. 111 izolatın her iki bileşiğe duyarlı olduğu ve hiç bir izolatın orta duyarlı olmadığı belirlendi. CLSI'nin kriterlerine göre 1 adet izolat fenotipik olarak GSBL pozitif, 111 adet izolat ise GSBL negatif olarak değerlendirildi. Dirençli ve duyarlı bulanan E. coli izolatlarının GSBL varlığı, GSBL üretilmesinden sorumlu olan bla genlerinden blaSHV geninin tespitine bağlı olarak polimeraz zincir reaksiyonu (PCR) ile değerlendirildi. blaSHV geninin hem GSBL pozitif hem de GSBL negatif E. coli izolatların hiçbirinde bulunmadığı belirlendi. Bu araştırmanın sonuçlarına göre dirençli ve MDR E. coli izolatlarının tek başına kullanılan β-laktam grubu bileşiklere karşı önemli düzeyde duyarlılıklarını yitirdikleri belirlenmiştir. Ancak GSBL nitelenmesi için gerekli olan klinik eşik değerlere sahip izolat sayısı çok düşüktür. Bu nedenle MDR ve GSBL arasında bağımlı ilişki değerlendirildiğinde GSBL varlığının her zaman MDR ile ilişkilendirilemeyeceği öngörülebilir
The aim of this study was to characterize the production extended-spectrum β-lactamase (ESBL) in multidrug resistant (MDR) Escherichia coli (E. coli) by phenotypic and genotypic methods. A total of 112 E. coli isolates with healthy and infectious findings were selected and included in the study. Phenotypic screening and validation tests were performed with broth-microdilution and disc diffusion methods to determine the antimicrobial resistance profiles of the isolates. Genotypic tests were performed with PCR. E. coli ATCC 25922 was used as control strain in antimicrobial susceptibility studies. MIC values of ceftazidime and cefotaxime drugs were evaluated by broth-microdilution method and disk diffusion method of these drugs both alone and in combination with clavulanic acid drugs (Clinical and Laboratory Standards Institute) were evaluated according to CLSI recommendations. While 92 isolates (82.14%) were susceptible to ceftazidime, 2 isolates (1.78%) were medium sensitive and 18 isolates (16.07%) were resistant to broth microdilution test. For cefotaxime, 45 isolates (40.17%) were susceptible, 35 isolates (31.25%) were moderately sensitive and 32 isolates (28.57%) were resistant. One of the isolates was resistant to ceftazidime (0.89%) and one to cefotaxime (0.89%). 111 isolates were sensitive to both compounds and no isolates were moderately sensitive. According to CLSI criteria, 1 isolate was phenotypically ESBL positive and 111 isolates were ESBL negative. The presence of ESBL in resistant and susceptible E. coli isolates was determined by polymerase chain reaction (PCR) for the blaSHV gene, one of the bla genes responsible for ESBL production. The blaSHV gene was found to contain none of the ESBL positive and ESBL negative E. coli isolates. According to the results of this study, resistant and MDR E. coli isolates lost significant sensitivity to β-lactam group compounds used alone. However, the number of isolates with clinical thresholds required for ESBL characterization is very low. Therefore, when the dependent relationship between MDR and ESBL is evaluated, it can be predicted that the presence of ESBL is not always associated with MDR.
The aim of this study was to characterize the production extended-spectrum β-lactamase (ESBL) in multidrug resistant (MDR) Escherichia coli (E. coli) by phenotypic and genotypic methods. A total of 112 E. coli isolates with healthy and infectious findings were selected and included in the study. Phenotypic screening and validation tests were performed with broth-microdilution and disc diffusion methods to determine the antimicrobial resistance profiles of the isolates. Genotypic tests were performed with PCR. E. coli ATCC 25922 was used as control strain in antimicrobial susceptibility studies. MIC values of ceftazidime and cefotaxime drugs were evaluated by broth-microdilution method and disk diffusion method of these drugs both alone and in combination with clavulanic acid drugs (Clinical and Laboratory Standards Institute) were evaluated according to CLSI recommendations. While 92 isolates (82.14%) were susceptible to ceftazidime, 2 isolates (1.78%) were medium sensitive and 18 isolates (16.07%) were resistant to broth microdilution test. For cefotaxime, 45 isolates (40.17%) were susceptible, 35 isolates (31.25%) were moderately sensitive and 32 isolates (28.57%) were resistant. One of the isolates was resistant to ceftazidime (0.89%) and one to cefotaxime (0.89%). 111 isolates were sensitive to both compounds and no isolates were moderately sensitive. According to CLSI criteria, 1 isolate was phenotypically ESBL positive and 111 isolates were ESBL negative. The presence of ESBL in resistant and susceptible E. coli isolates was determined by polymerase chain reaction (PCR) for the blaSHV gene, one of the bla genes responsible for ESBL production. The blaSHV gene was found to contain none of the ESBL positive and ESBL negative E. coli isolates. According to the results of this study, resistant and MDR E. coli isolates lost significant sensitivity to β-lactam group compounds used alone. However, the number of isolates with clinical thresholds required for ESBL characterization is very low. Therefore, when the dependent relationship between MDR and ESBL is evaluated, it can be predicted that the presence of ESBL is not always associated with MDR.
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Keywords
MDR, E. coli, GSBL, Antimikrobiyal direnç, Antimicrobial resistance
Citation
İbrahimli, U. (2019). Çoklu antimikrobiyal dirençli escherichia coli'de genişlemiş spektrumlu β-laktamaz direncinin karakterizasyonu. Yayınlanmamış yüksek lisans tezi. Bursa Uludağ Üniversitesi Sağlık Bilimleri Enstitüsü.