Iodometric and Molecular Detection of ESBL Production Among Clinical Isolates of E. coli Fingerprinted by ERIC-PCR: The First Egyptian Report Declares the Emergence of E. coli O25b-ST131clone Harboring bla.

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.