CRUDE EXTRACTS OF FECAL BACTERIA ISOLATED FROM PHILIPPINE NATIVE CHICKEN (GALLUS GALLUS DOMESTICUS) SHOW IN VITRO ANTIMICROBIAL ACTIVITY AGAINST ESCHERICHIA COLI

The study isolated and prepared crude extracts of fecal bacteria from four known strains of Philippine native chicken. It also evaluated the antimicrobial activity of the crude extracts against E. coli as indicator bacteria and compared to selected antimicrobials using modified disc diffusion method. Fecal suspensions were plated on nutrient agar and then incubated at 37 ºC for 24 to 48 h. Colonies were purified and two distinct isolates were characterized morphologically through Gram-staining. A loopful of bacteria was inoculated in 10ml nutrient broth and incubated at 37 ºC at different time intervals (6, 12, 18 and 24 h), then centrifuged and the cell-free supernatant (crude extract) was collected. Filter paper disc was impregnated with a total of 30 µl of crude extract and was used for antimicrobial activity testing along with three selected antimicrobial discs against E. coli. A total of 26 bacterial isolates was identified while two distinct colony morphologies were observed, and all isolates have rod shape appearance. The incubation period with the greatest number of isolates with zone of inhibition is 6 h, while the strain with the greatest number of isolates having zone of inhibition was Joloanon. All crude extracts showed significantly higher antimicrobial activity compared to these two antimicrobials except gentamicin.