Prevalence, Risk Factors and Molecular Characterization of Extended Spectrum ß-Lactamases (ESBLS) from Uropathogenic Escherichia Coli and Klebsiella Pneumoniae among Pregnant Women in Nnewi, Nigeria

Abstract

Urinary tract infection (UTI) occurs frequently during pregnancy due to a wide range of physiological and hormonal changes. Extended Spectrum β-lactamase (ESBL) producing UTI is an important public health issue due to lack of therapeutic antibiotic options and the danger it portends to the pregnant woman. This study was carried out to determine the prevalence of ESBL bearing uropathogens among pregnant women in Nnewi. Questionnaires were used to obtain demographic information and clinical history. E. coli and K.pneumoniae isolated using microbiological methods were analyzed for antibiogram and resistance genes. Urine samples were collected from one hundred and seventy-five pregnant women during antenatal clinics in three different hospitals across the breadth of Nnewi North L.G.A of Anambra State. Samples were cultured on routine laboratory media. Identification of isolates was carried out using standard biochemical tests and identification media. Antibiogram studies were carried out using fifteen antibiotics spanning seven different classes. Modified Double Disc Synergy test (MDDST) was carried out on some selected isolates to confirm the presence of ESBL phenotypically. Plasmid profiling studies were carried out on selected multi-drug resistant isolates. Conjugation and plasmid curing studies were also done to determine the resistance factor. Molecular characterization of the phenotypically confirmed ESBL positive isolate using PCR was done. Three ESBL primers (bla-TEM, bla-SHV, bla-CTX-M) were employed. A total of 192 isolates were obtained of which 75(39.1%) were E. coli and 117(60.9%) were K. pneumoniae. One hundred and thirty (74.3%) of the pregnant women had ESBL-producing UTI. Demographic distribution shows higher incidences among 25-28years of age (34.2%), those in their 3rd trimester (50%) and among those who stopped their education at the secondary level (71.1%). Pregnant women asymptomatic for UTI had the highest prevalence of the ESBL-producinginfections compared to those who were symptomatic. There was a significant statistical difference between educational background, presence/absence of symptoms of UTI and presence of ESBLs (P < 0.05). Isolates were 100% resistant to all the cephalosporin antibiotics (ceftazidime, cefuroxime, cefixime and ceftriaxone) employed in this study with varying levels of resistance to a host of non-ß-lactam antibiotics. Curing studies were largely ineffectual as the isolates retained their resistance determinants despite varying the concentration of the acridine orange. Conjugation studies were also ineffective as there was no transfer of ESBL determinants to non-ESBL producing strains. Molecular characterization of the ESBL types revealed a predominance of bla-TEM (91.9%), followed by bla-SHV (73.3%) and bla-CTX-M (56.8%). Majority of the isolates harbored multiple ESBL genes. Our findings suggest indiscriminate use of high profile antibiotics as a possible cause of development, sustenance and transfer of ESBL traits among the studied population. Tighter regulations on antibiotic distribution coupled with a more careful antimicrobial surveillance to check the spread of these resistance traits within the population is recommended. Proper hygiene among pregnant women should be thoroughly emphasized and there should be routine screening of pregnant women to check for these resistance determinants during antenatal clinics.