ABSTRACT

Extended spectrum beta-lactamases (ESBL) are enzymes produced by members of the Enterobacteriaceae which can hydrolyze the beta-lactam antibiotics such as penicillins and cephalosporins, and thereby conferring antibiotic resistance on strains producing them. Bacterial isolates producing ESBLs have spread to different parts of the world. The ESBLs are encoded by several different genetic elements borne on the chromosome and plasmids. This study was carried out to investigate the prevalence of ESBL producing bacterial uropathogens among asymptomatic pregnant women in the study area and to characterize the genes associated with ESBL among the isolates. Mid-stream urine sample was collected from a total of 660 pregnant women between July and December 2018. A questionnaire to access the risk factors for acquiring ESBL producing bacteria was filled. The specimens were inoculated on MacConkey agar and incubated at 37^oC for 24h. The biochemical characterization of the isolates was done using the Microbact 24E (Oxoid Ltd, UK). Antibiotic susceptibility testing was done by Kirby-Bauer disc agar diffusion method. The isolates were tested for the production of ESBL, using Double Disk Synergy test and CHROMagar ESBL. Genomic and plasmid DNA from ESBL producing strains was extracted and amplified using the Polymerase Chain Reaction (PCR) with primers for bla_TEM, bla_SHV and bla_CTX-M-15genes. A total of 252 uropathogenic bacterial isolates were encountered. Of this number, 231 (92%) were ESBL producers. The distribution of bacterial pathogens were as follows: Enterobacter cloacae (25.7%) followed by Escherichia coli (20.2%), Klebsiella pneumoniae (16.3%), Citrobacter spp. (1.2%), and Hafnia alvei (6.7%). E. cloacae were the most frequently isolated ESBL producer (25%), followed by E. coli (19%) and K.  pneumoniae (15%). There was significant association (P<0.005) between age, marital status, previous use of antibiotics, personal hygiene and parity with the occurrence of ESBL producing bacteria. Extended spectrum beta-lactamase producers revealed a higher level of antibiotic resistance (90%) compared to non-ESBLs. Carbapenems were the most effective treatment options for these bacteria. Genotypic characterization of the ESBL producing isolates showed bla_CTX-M-15 to be the most prevalent (26%). The carriage of multiple bla genes was low, ranging from 2-6 % of different combinations. This study has shown the existence of multiple bla genes in the Gram-negative bacterial isolates from pregnant women in Ikot Ekpene, Eket and Oron Local Government Areas. This calls for appropriate antibiotic use through creating awareness in order to combat the potential negative effects of the spread of resistant bacteria carrying genes for resistance to extended spectrum beta-lactam antibiotics.