Comparison of the Efficacies of Commonly Used Antibiotics for the Treatment of Salmonella enterica Serovar Typhi Infection


Owolabi Oluwabusuyi Jacob, Alo Moses Nnaemeka, UGAH UCHENNA, Olaosebikan Oluwatosin Oluwatoyin, Afolabi O.R, Onuoha Stephen Ndubuisi.


Most antibiotics available for the treatment of Salmonella enterica serovar typhi have been reported to be ineffective at adequate concentrations; therefore the need to determine the efficacies of some of the commonly used antibiotics for the treatment of the etiological agent of typhoid fever. Kirby-Bauer disk diffusion method, determination of MIC using agar diffusion method and in vivo antibiotic assay was used to analyze the susceptibility pattern of Salmonella enterica serovar typhi to different antimicrobial agents. The zones of inhibition to the predetermined battery of antibiotics on the medium shielded with Salmonella enterica serovar typhi indicated that ciprofloxacin had the highest zone of inhibition (24 mm) while amoxicillin and chloramphenicol had 8 mm each. The minimum inhibitory concentration (MIC) of ciprofloxacin was found to be 3.65 µg/ml while those of amoxicillin and chloramphenicol were 124 µg/ml and 228 µg/ml respectively. There was significant difference (P<0.05) in the number colony forming units (cfu) of Salmonella enterica serovar typhi of the treated rats compared with the untreated ones. Histopathological examination of the liver and kidney of the treated rats revealed that there was tissue degradation, necrosis, heamosiderosis in the organs of rats treated with amoxicillin and chloramphenicol at concentration of 100 and 150 mg/kg and tissue proliferation by viable Salmonella enterica serovar typhi at 50 mg/kg. Out of all the antibiotics tested, ciprofloxacin was the only antibiotics found to be of good efficacy for the treatment of Salmonella enterica serovar typhi. We therefore advocate for continous surveillance on the susceptibility pattern of this organism.


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