Multidrug Resistant Salmonella enterica Strains in South Western Nigeria: Prevalence and Susceptibility to Ceftriaxone

Aims: To investigate the prevalence and susceptibility pattern Salmonella enterica strains to ceftriaxone in southwestern Nigeria.

Place and Duration of Study: Faculty of Pharmacy, University of Ibadan, Nigeria from November 2012-May 2013.

Methodology: Isolates of Salmonella enterica were characterized by established standard cultural and biochemical tests and was screened in-vitro for their sensitivity to different antibiotics (ampicillin, amoxicillin, chloramphenicol, cotrimoxazole and ceftriaxone) using the agar well diffusion method and their MICs determined.

Results: The susceptibility pattern of these strains to ceftriaxone and other antibiotics was examined to determine their prevalence among patients in South West Nigeria. 21 clinical isolates were screened in-vitro against five antibiotics. A higher number of the isolates showed MDR (76.19%) even at higher concentration of the antibiotics, while 61.9% were sensitive to ceftriaxone. Among the isolates, 71.43% resistance was recorded against ampicillin, 66.67% against amoxicillin, 38.1% resistance against ceftriaxone, 80.95% resistance against chloramphenicol and 57.14% resistance against cotrimoxazole. However, 3 isolates (14.29%) were completely sensitive to all of the antibiotics. The MICs obtained were higher (ranging from 30µg/ml to >100µg/ml), compared to the CSLI breakpoint standard. The result obtained showed an increased in incidence of MDR S. enterica strain in southwestern Nigeria, and that ceftriaxone is still remain the drug of choice against Salmonella enterica strains, even though the number of isolates producing resistance against the antibiotics is on the increase.

Conclusion: The results above proces that the rate and prevalence of MDR Salmonella enterica strains are of major concern mostly in developing countries, therefore clinicians and public health practitioners should reduce the rate of antibiotic prescriptions and encourage public health and personal hygiene to prevent S. enterica infection.