Evaluation of presence of clone ST131 and biofilm formation in ESBL producing and non-producing Escherichia coli strains.

OBJECTIVE: Escherichia coli ST131 is a pandemic clone associated with multidrug resistance, starting with beta-lactamase production and fluoroquinolone resistance in the first place, leading to significant systemic infections. Clones that develop due to the frequency of antimicrobial resistance and the rate of spread in our country are important issues that need to be investigated. This study aims to investigate the incidence of ST131which is a "high-risk pandemic clone E. coli" in ESBL-producing and non-ESBL-producing strains, as well as their biofilm-forming abilities and antibiotic resistance rates.

MATERIALS AND METHODS: A total of 86 E. coli isolates were used in the study. Bacterial identifications were performed by conventional and automated methods. The double disc synergy method was used to demonstrate the presence of ESBL. Molecular studies in all E. coli strains were performed by real-time PCR method.

FINDINGS: 86 strains were studied, of which 83.72% were urine, 6.98% were wound, 4.65% were blood, and 2.33% were tracheal aspirate and sputum. 79.07% of these strains were ESBL-positive. 58.1% of the strains were female, whereas 41.9% were male patients, and the average age was 46.2. Out of 86 strains, 38.72% were ST131 positive, the H30 subclone was detected in 27.27% of them, and the H30-Rx subclone was detected in all of the H30 subclone positive strains. The presence of the ESBL resistance gene was detected at the rate of TEM 41.86%, SHV 37.21%, CTX-M 36.04%, and OXA 4.65%. Most commonly SHV gene (54.54%) was seen in ST131 clone-positive samples. Finally, while it was found that 48.83% of the strains formed biofilm by any method, biofilm formation was detected in 69.7% of the samples that were positive for the ST131 clone.

RESULT: Our study can reveal the dramatic prevalence of the ESBL-producing E. coli strains along with the high-risk ST131 clone, the dominance of the H30Rx subclone of this risky clone, as well as the importance of the influence of resistance mechanisms along with resistance and biofilm.