ENUMERATION AND DETECTION OF ANTIBIOTIC SUSCEPTIBILITY PATTERN OF COLIFORM BACTERIA FROM MILK SAMPLES IN KATHMANDU.

Abstract

The presence coliforms and their resistance in milk is the big issue in present time. Milk is an excellent source of nutrients and also serves as a good medium for the growth of milk-borne pathogens. Cross-sectional study was conducted to assess and compare microbial quality of raw milk and pasteurized milk and also determine antimicrobial susceptibility patterns of coliforms from the milk samples. For this, 30 milk samples (15 raw and 15 pasteurized milk) were collected from different locations of Kathmandu district. Starch adulteration test and MBRT were done. TCC, FCC for each sample were determined by pour plate technique and interpretated with BIS guidelines (1992), DFTQC guidelines and identification was done. Antibiotic susceptibility testing of isolates was carried out by Kirby Bauer disk diffusion method using 12 different antibiotics. TCC of the 12 raw samples were higher than the guideline and its FCC was also found to be higher in 9 samples. In case of pasteurized samples, TCC was higher in 6 samples and FCC in 4 samples. A total of 31 isolates, 21 from raw samples and rest from pasteurized samples were identified. Out of 31 isolates, 17 (54.84%) were identified as Klebsiella spp., 13 (41.94%) were E. coli and 1 (3.22%) was Citrobacter spp. AST of coliform isolates were 100% sensitive against TE. 96.77% of the isolates were sensitive towards NIT, PIT, COT, C and AK. Out of total, 11 (35.48%) were MDR (Multi-Drug Resistant). Among them, 7 (63.64%) were from raw samples and rest 4 (36.36%) from pasteurized samples. Although, quality of most of the samples were good as per MBRT but the presence of antimicrobial resistant bacteria and adulterants questions the overall quality ofmilk. Thus, it is concluded that the milk produced by small-scale farm from the studied area are not of good quality, caused by coliforms especially the antibiotic resistant. Therefore, such type of study for monitoring the microbial quality of milk should be done in order to safeguard the consumers. Otherwise, it will be hazardous for the consumers and can be a potential source of milk-borne infections.