Prevalence of extended-spectrum beta-lactamase production in clinical Escherichia coli isolates in Ibadan metropolis, south-west Nigeria

Background: Escherichia coli is a major extended spectrum beta-lactamase-producing organism. Extended spectrum beta-lactamases (ESBLs) inactivate newer cephalosporins through hydrolysis increasing therapeutic failure and antibiotic resistance worldwide. This prospective experimental study aimed to determine the antibiotic susceptibility profile and ESBL production by clinical E. coli isolates.Methods: Fifty-one clinical E. coli isolates were obtained from the microbiology laboratories of University College Hospital, Adeoyo Maternity Hospital, Our Lady of Apostle Hospital, and a private diagnostic laboratory all in Ibadan metropolis. They were identified and confirmed using standard biochemical tests. Kirby-Bauer disc diffusion method was used to determine the antibiogram and interpreted using clinical laboratory standard institute (CLSI) guideline. ESBL production was determined by the double disk synergy test (DDST).Results: The prevalence of ESBL production was observed to be 78.4%(40). Resistance was common to sulphamethozaxole/trimethoprim 96.0%(49), ceftazidime 94.1%(48), amoxicillin and tetracycline 92.1%(47), fosfomycin 84.3%(43), cefotaxime 76.4%(39), ciprofloxacin 60.7%(31), amoxicillin/clavulanic acid 58.8%(30), and chloramphenicol 50.9%(26). Meropenem was observed to be the most sensitive (100.0%), followed by nitrofurantoin 78.4%(40), and gentamicin 70.5%(36). Multiple antibiotic resistance (MAR) index greater than 0.2 was observed in 98.0%(50) of the isolates.Conclusion: Majority of the clinical isolates of E. coli were ESBL producers which are resistant to frequently used antibiotics.Keywords: Escherichia coli, Extended spectrum beta-lactamase, Antibiotic resistanc

Assessment of the efficacy of selected disinfectant formulations against clinical isolates of Staphyloccocus aureus from a tertiary Hospital in Ibadan, Nigeria

Background: S. aureus is one of the most common causes of nosocomial infections and can cause a range of illnesses, from minor skin infections to life threatening diseases.Objective: This study was done to assess the efficacy of some commercially available disinfectants and to determine the antimicrobial susceptibility profile of clinical S. aureus isolates.Material and Methods: Fifty S. aureus isolates were obtained from the Microbiology unit of the University College Hospital, Ibadan and characterized by standard biochemical tests. The efficacy of the test disinfectant formulations was assessed using standard method. Antimicrobial susceptibility profile of the clinical isolates to commonly prescribed antibiotics was determined by modified Kirby-Bauer method.Results: Salvon ® was most effective with 100% efficacy both at the manufacturer’s in-use concentration and double. Dettol® showed 76% efficacy at the  manufacturer’s in-use concentration and 100% efficacy when concentration wasdoubled. Jik® showed activity only when the manufacturer’s in-use concentration was doubled with 94% efficacy. All the isolates were resistant to Germicide® both at the manufacturer’s in-use concentration and double. The isolates (68%) were observed to be most susceptible to Ofloxacin, 44% susceptibility to Gentamicin, 10% susceptibility to Cefuroxime and Amoxycillin/Clavulanate respectively. Only 4% susceptibility was observed to cloxacillin, and 100% resistance was observed to Erythromycin.Conclusion: Savlon® was the most effective disinfectant, and Germicide® the least (even at double manufacturer’s inuse concentration). Majority of the isolates (96%) were found to be multidrug resistant.Keywords: S. aureus, Chemical disinfectants, Manufacturers’ concentration,  Microbial resistance