THE POTENTIALS OF SECONDARY METABOLITES FROM Bacillus spp., Comamonas spp. AND Lysinibacillus spp. AGAINST DOXYCYCLINE RESISTANT BACTERIA

Antibiotic resistance is a phenomenon which is based on loss of bacterial susceptibility to an antibiotic's bactericidal or bacteriostatic effects. The emergence of multiple drug-resistant pathogenic microbes generates the requirement to investigate for new efficient antibiotics against them. Therefore, this study aims to isolate and characterize the potential antibiotic producing bacteria from meat samples and to optimize the temperature which facilitates the best antibiotic producing activity. Ten bacteria were isolated by crowded plate technique which were then characterized by 8 biochemical tests (oxidase test, catalase test, methyl red test, Voges-Proskauer test, gelatin hydrolysis test, TSI test, citrate test, indole test). One Klebsiella spp., six Pseudomonas spp., one Comamonas spp., one Bacillus spp. and one Lysinibacillus spp. were identified by observing colony morphology and the results of biochemical tests. Later, Bacillus spp., Comamonas spp. and Lysinibacillus spp. were allowed to secrete secondary metabolites in fermentation broth at 24⁰C, 27⁰C and 30⁰C temperature. The crude extracts were derived from each isolate and assessed their antibacterial activity against K. pneumoniae, A. hydrophila and Enterobacter spp. using Kirby-Bauer’s disc diffusion method. Secondary metabolites from each of these three bacterial fermentations at 30⁰C showed the zones of inhibition of maximum diameter (ranging from 10.8 mm to 11.4 mm). In conclusion, secondary metabolite compounds produced by Bacillus spp., Comamonas spp. and Lysinibacillus spp. possess the capacity to inhibit pathogenic bacteria (K. pneumoniae, A. hydrophila and Enterobacter spp.). Hence, each of the samples are potential candidates for anti-pathogen development.

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