El-Badawy Mohamed F, Tawakol Wael M, Maghrabi Ibrahim A, Mansy Moselhy S, Shohayeb Mohamed M, Ashour Mohammed S
1 Department of Microbiology and Immunology, Faculty of Pharmacy, Misr University for Science and Technology , Cairo, Egypt .
2 Department of Pharmaceutical Microbiology, College of Pharmacy, Taif University , Taif, Saudi Arabia .
Microb Drug Resist. 2017 Sep;23(6):703-717. doi: 10.1089/mdr.2016.0181. Epub 2017 Jan 18.
The extensive use of β-lactam antibiotics has led to emergence and spread of extended-spectrum β-lactamases (ESBLs). This study was conducted to investigate the prevalence of 7 different ESBL genes (bla, bla, bla, bla, bla, bla, and bla) and O25b-ST131 high-risk clone among 61 clinical isolates of Escherichia coli. Also, one broad-spectrum β-lactamase (bla) was investigated. This study was also constructed to evaluate iodometric overlay method in detection of ESBL production. Phenotypic identification of E. coli isolates using API 20E revealed 18 distinct biotypes. DNA fingerprinting using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) differentiated all isolates into 2 main phylogenetic groups with 60 distinct genetic profiles. Elevated values of minimal inhibitory concentration (MIC) and MIC for third- and fourth-generation cephalosporins were observed. Phenotypic tests revealed that 85.24% of isolates were ESBL producers. The incidence rates of bla, bla, bla, bla, bla, and bla among E. coli ESBL producer phenotype were 69.23%, 25%, 96.15%, 3.85%, 11.54%, and 48%, respectively. On the other hand, bla and bla were not detected. Sequencing of bla and bla revealed that bla and bla were the most prevalent variants. Group characterization of bla revealed that bla was the most prevalent group of bla family. It was found that 30.77% of E. coli ESBL producers belonged to O25b-ST131 clone harboring bla. This study concluded that iodometric overlay method was 100% sensitive in detection of ESBL production. To our knowledge, this is the first Egyptian study that declares the emergence of E. coli O25b-ST131 harboring bla.
β-内酰胺类抗生素的广泛使用导致了超广谱β-内酰胺酶（ESBLs）的出现和传播。本研究旨在调查61株临床分离的大肠杆菌中7种不同ESBL基因（bla、bla、bla、bla、bla、bla和bla）以及O25b-ST131高危克隆的流行情况。此外，还对一种广谱β-内酰胺酶（bla）进行了研究。本研究还构建了用于评估碘量法覆盖法检测ESBL产生的方法。使用API 20E对大肠杆菌分离株进行表型鉴定，发现了18种不同的生物型。使用肠杆菌重复基因间共识聚合酶链反应（ERIC-PCR）进行DNA指纹图谱分析，将所有分离株分为2个主要系统发育组，具有60种不同的遗传图谱。观察到第三代和第四代头孢菌素的最低抑菌浓度（MIC）和MIC值升高。表型试验显示，85.24%的分离株为ESBL产生菌。在大肠杆菌ESBL产生菌表型中，bla、bla、bla、bla、bla和bla的发生率分别为69.23%、25%、96.15%、3.85%、11.54%和48%。另一方面，未检测到bla和bla。bla和bla的测序显示，bla和bla是最常见的变体。bla的分组特征显示，bla是bla家族中最常见的组。发现30.77%的大肠杆菌ESBL产生菌属于携带bla的O25b-ST131克隆。本研究得出结论，碘量法覆盖法在检测ESBL产生方面具有100%的敏感性。据我们所知，这是埃及第一项宣布携带bla的大肠杆菌O25b-ST131出现的研究。
