African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5233

Full Length Research Paper

Antimicrobial susceptibility of Escherichia coli and other coliforms isolated from urine of asymptomatic students in Bayelsa State, Nigeria

Yakubu B. Ngwai1*, Mark O. Akpotu2, Ruth E. Obidake2, Adebukola A. Sounyo2, Adebola Onanuga2 and Samuel O. Origbo2
  1Microbiology Unit, Department of Biological Sciences, Nasarawa State University, P. M. B. 1022, Keffi, Nasarawa State, Nigeria. 2Department of Pharmaceutical Microbiology and Biotechnology, Faculty of Pharmacy, Niger Delta University, Wilberforce Island, P. M. B. 071, Yenagoa, Nigeria.
Email: [email protected]

  •  Accepted: 08 April 2010
  •  Published: 02 February 2011



This study investigated the isolation rate and antimicrobial susceptibility of Escherichia coliand other coliforms from asymptomatic male and female students of Niger Delta University in Bayelsa State, Nigeria. E. coli and other coliforms from midstream clean-catch urine samples of asymptomatic male and female students were isolated and tested for their susceptibility to commonly used antimicrobial agents using the disk diffusion protocol described by the Clinical Laboratory Standards Institute (CLSI). Of the few subjects that harbored Ecoli, more were males. Zone sizes for both isolate groups from males were higher than those from females. Ecoli were more susceptible to the antimicrobials than the non - Ecoli (unclassified coliform) isolates for both subjects, although the overall susceptibility of both isolate groups was poor. Gentamicin was the most active (64.5% for Ecoli and 33.3% for unclassified coliforms) while tetracycline was the least (22.7% for Ecoli and 0% for unclassified coliforms). The most common resistance phenotypes were “ATCtGSNa” (for Ecoli) and “ATCtGSNaNC” (for unclassified coliforms); “ATCtGSNaNC” was observed in both isolate groups. Multiple antibiotic resistances were observed significantly in both Ecoli (83.9%) and the unclassified coliforms (100%). As against 9.7% of the Ecoli isolates, 40% of the unclassified coliforms were resistant to all the antimicrobials. MAR indices were very high (all above 0.2) in both isolate groups. Although asymptomatic male students of Niger Delta University harbored more Ecoli than the female students, isolates from the female students pose greater risk of antimicrobial resistance owing to their lower susceptibility to antimicrobials compared with those from their male counterparts. The prior exposure of all the isolates to antibiotics as suggested by their high MAR indices provides justification for continuous monitoring of bacterial susceptibility to antibiotics before prescription in order to ensure adequate treatment of infections arising from urinary pathogens and reduction in the spread of bacteria resistant strain.


Key words: Escherichia coli, urine, asymptomatic, antimicrobial susceptibility.