Prevalence and molecular characterization of extended spectrum beta-lactamase producing uropathogenic Escherichia coli in a tertiary health care facility in Anambra State, Nigeria

Background: The prevalence of ESBLs-producing Escherichia coli has recently increased worldwide due to the expression of ESBL genes which had led to high rate of multidrug resistance antibiotics.

Aim: To determine the antimicrobial susceptibility patterns of E. coli isolates and evaluating the ESBL carriage of these isolates at phenotypic and genotypic levels.

Methods: One hundred and two clinical Escherichia coli isolates were recovered from UTI suspects and analyzed for ESBL production at phenotypic and genotypic levels using Modified Double Disc Synergy Test and Polymerase Chain Reaction respectively.

Results: Of the 102 isolates, 100(98.04%) were associated with MDR phenotypes. The isolates showed variable resistance to all the antibiotics used in the study. The resistance rates were 99.0%, 97.1%, 88.2%, 82.4%, 81.4%, 65.7%, 54.9%, 46.1%, 46.1%, 23.5% for ampicillin, trimethoprim-sulfamethoxazole, ciprofloxacin, ceftriaxone, ceftazidime, amoxicillin-clavulanate, gentamycin, cefoxitin, nitrofurantoin and imipenem, and respectively. The prevalence of phenotypic ESBL production was 74.5%. Based on the PCR results, the randomly selected 20 ESBL-positive isolates possessed one or more ESBLs genes. CTX-M type was the predominant ESBLs type (100%), while those for TEM and SHV-types were 85% and 80% respectively. Four genotype patterns were detected (CTX-M, TEM+CTX-M, SHV+CTX-M and SHV+TEM+CTX-M). The genotype SHV+TEM+CTX-M, was the predominant (70%), followed by the genotype TEM +CTX-M combination (15%). The occurrences of the genotypes, CTX-M and SHV+CTX-M were 5% and 10% respectively.

Conclusion: This study found a high rate of Phenotypic ESBL production (74.5%) among the isolates with multidrug resistance, CTX-M as the predominant ESBLs type (100%) and combination of SHV+TEM+CTX-M as the predominant genotype (70%).