[1],2Oluwatobi, O. B., *1,3Igbokwe, C. O., 1,4Famojuro, O. B., and 1Adeleke, O. E.
1Department of Pharmaceutical Microbiology, Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria
2Department of Medical Laboratory Science, Atiba University, Oyo, Nigeria
3Department of Pharmaceutical Microbiology and Biotechnology, Lead City University Ibadan, Nigeria
4Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Olabisi Onabanjo University, Sagamu, Nigeria
*Correspondence to: igbokwe.christopher@lcu.edu.ng; +2348062895635; ORCiD: https://orcid.org/0000–0001–7379–6503
Abstract:
Background: Urinary tract infection (UTI) largely affects women and is mostly caused by bacteria, among which coagulase negative staphylococci has received little attention. The objectives of this study are to isolate and genotypically identify coagulase negative staphylococci (CoNS) from urine samples of adult females attending selected healthcare facilities from three States (Oyo, Osun and Ogun) in southwest Nigeria, and to determine their susceptibility to selected antibiotics.
Methodology: A case-control study of 471 adult female participants with urinary symptoms in 205 (case) and no urinary symptoms in 266 (control), was conducted over a period of 10 months. Mid-stream voided urine samples were collected from the participants. The samples were cultured on mannitol salt and blood agar plates, and bacteria growths were presumptively identified for CoNS and other bacterial isolates using routine biochemical tests. The CoNS isolates were confirmed by conventional PCR amplification with Staphylococcus saprophyticus specific primers and 16S rRNA sequencing with phylogenetic analysis using MegaX software 18 version 10.0.5. Antibiotic susceptibility testing was performed on genotypically identified CoNS isolates using VITEK 2 system. Chi square and Fisher Exact tests were used to compare the prevalence of bacterial UTIs across the States and between symptomatic and asymptomatic participants at α=0.05.
Results: Of the urine samples of 471 participants examined, 178 (37.8%) had bacterial UTIs on cultures, 66 of
117 (56.4%) were from Oyo State, 98 of 241 (40.7%) from Osun State, and 14 of 113 (14.1%) from Ogun State (x2=49.113, p<0.0001). A total of 34 (7.2%) CoNS isolates were phenotypically identified, with 29 (14.1%) from 205 symptomatic and 5 (1.9%) from 266 asymptomatic participants (OR=8.601, 95% CI=3.266-22.653, p<0.0001). Staphylococcus saprophyticus PCR amplified 19 of the 34 CoNS isolates while 16S rRNA sequencing identified 5 CoNS species among the 19 isolates, with S. saprophyticus (n=10, 52.6%) S. lentus (n=5, 2.8%), S. xylosus (n=2, 1.1%), S. sciuri (n=1, 0.6%), and S. rodentium (n=1, 0.6%). All the CoNS isolates were resistant to daptomycin, sulfamethoxazole-trimethoprim and oxacillin indicating they were multi-drug resistant (MDR) but were all sensitive to nitrofurantoin.
Conclusion: The high resistance rates to commonly used antibiotics such as the β-lactams, sulfamethoxazoletrimethoprim and daptomycin from our study underscore the need for routine genotypic surveillance and antibiotic stewardship in the management of UTIs. Our findings emphasize the clinical relevance of CoNS in UTIs and the necessity for targeted diagnostics and treatment strategies.
Keywords: Staphylococcus saprophyticus, Urinary tract infection, multi-drug resistance
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