ANTIBIOTIC SUSCEPTIBILITY OF MICROBIAL CONTAMINANTS FOUND IN COMMERCIALLY AVAILABLE QUININE SYRUPS AND INJECTION WATERS SOLD IN OWERRI, IMO STATE NIGERIA

Antimicrobial susceptibility tests were carried out on bacteria isolated from quinine syrups and water for injections. Bactria isolates from quinine syrups and injection water samples were identified as Bacillus sp. and Staphylococcus sp. and are designated as Bacillus sp. 2S2 and Staphylococcus sp. 2S3 for quinine samples and Bacillus sp. 2W1 and Staphylococcus sp. 3W3 for the injection water samples. The susceptibility test was carried out using the Mueller-Hinton broth dilution method supplemented with 0.1% (w/v) of tetrazolium chloride as an indicator dye at 37⁰C and also the Mueller-Hinton agar disk diffusion method supplemented with 0.1% (w/v) of tetrazolium chloride indicator dye. Four different antibiotics including Ofloxacin, Cefixime, Ciprofloxacin and Levofloxacin were used at different concentrations range of 0 – 1000µg/ml for Ofloxacin and Cefixime and 0 - 2000µg/ml for ciprofloxacin and Levofloxacin. Ofloxacin showed a higher inhibition on the Staphylococcus sp. 2S3 and Bacillus sp. 2S2 than the Bacillus sp. 2W1 and Staphylococcus sp. 3W3, while Ciprofloxacin, Levofloxacin and Cefixime showed a higher inhibition on Bacillus sp. The minimum inhibitory concentrations (MIC) of each of the antibiotics were estimated by application of IC₅₀ using macrobroth dilution procedure. Out of the 20 analysed samples of quinine and 10 injection waters, 17 quinine syrups and 8 injection waters were contaminated.