PREVALENCE AND MOLECULAR CHARACTERIZATION OF ESCHERICHIA COLI ST131 ISOLATES FROM PATIENTS AT A TERTIARY-CARE HOSPITAL IN PHAYAO PROVINCE, THAILAND (MARCH 2015 - JUNE 2017)

Abstract

Escherichia coli is a common cause of infection and its identification and characterization provide appropriate and effective antimicrobial treatment. Phylogenetic group and ST131 strain and subtypes of clinical E. coli isolates (n = 58, 59% being urine samples) from patients attending a tertiary care hospital in Phayao Province, northern Thailand during March 2015 and June 2017 were identified using a Clemont protocol and multiplex PCR respectively, and presence of ?-Lactamase genes (blaCTX-M, blaOXA and blaTEM) and mutation of gyrA and parC were determined by multiplex and allele-specific multiplex PCR respectively. Antibiogram profiling showed 95, 66 and 48% of the strains were resistant to ampicillin, four fluoroquinolones (carrying mutations in fluoroquinolone resistance-determining regions of GyrA and ParC) and all four fluoroquinolones together with ESBL production (carrying in addition blaCTX-m1 or blaCTX-m9 and integron 1), respectively. While only 31% of the strains were E. coli ST131, 67% were from urine specimens and 78% from patients >40 years of age, with 72 % belonging to subtypes A and C2 and 33 % to subtypes C1-M27 and C1-non-M27. Proportion of ST131 strains increased from 10% in 2015 to 30% in 2016 and to 73% in 2017 (in latter period samples were collected only in the first six months). In conclusion, PCR-based techniques allowed rapid and facile detection of antibiotic-resistance genes and virulence genetic markers in clinical E. coli isolates allowing prompt and appropriate antimicrobial treatment of patients and, in addition, providing molecular signatures for epidemiological surveillance.