Antibiotic Susceptibility, Molecular Characterization and Detection of TSST Gene in S. aureus and LT Gene in E. coli Isolates from Public Toilets in Port Harcourt, Nigeria

Abstract

Public toilet environments may harbour bacteria with antimicrobial resistance and virulence-associated genes. This study assessed the antibiotic susceptibility and molecular characteristics of Staphylococcus aureus and Escherichia coli recovered from toilet bowls and seats in public facilities in Port Harcourt, Nigeria. Isolates were identified using cultural and biochemical characteristics, and antibiotic susceptibility was assessed by disc diffusion on Mueller–Hinton agar. Molecular investigations included 16S rRNA and gyrA amplification and screening for toxic shock syndrome toxin (TSST) and heat-labile toxin (LT) genes. Staphylococcus aureus isolates were fully susceptible to ciprofloxacin and gentamicin, while susceptibility to levofloxacin and azithromycin was 96% and 93%, respectively. Resistance to ceftazidime and cefuroxime was 75% and 71%, respectively. Escherichia coli exhibited complete susceptibility to ciprofloxacin, ofloxacin and peflacine, but resistance to ceftazidime, cefuroxime and ceporex was 100%, approximately 94% and approximately 88%, respectively. Multiple antibiotic resistance indices were generally higher among Escherichia coli isolates. Molecular characterisation involved six Staphylococcus aureus and four Escherichia coli isolates, with gyrA and 16S rRNA amplification reported. All six tested Staphylococcus aureus isolates yielded TSST-associated amplicons, and all four Escherichia coli isolates yielded LT-associated amplicons. These findings document varied antibiotic susceptibility and the presence of selected virulence-associated gene markers in bacteria recovered from the sampled public toilets. Regular environmental microbiological surveillance and appropriate sanitation practices are warranted.