Probiotic Characterization of Enterococcus spp. Isolated from Raw Goat Milk

Abstract: The aim of this research was to determine the probiotic potential and safety of lactic acid bacteria (LAB) isolated from raw goat milk. Gram positive and catalase negative bacteria were isolated from raw goat milk (n = 61) and identified as LAB. LAB isolates were screened for antimicrobial, probiotic and technological characteristics. LAB isolates showed antimicrobial activity against foodborne pathogens (Staphylococcus aureus, Escherichia coli and Salmonella Typhimurium) and high survival rate at pH 2 (93.54-100.38% after 4h), in the presence of 0.3% bile salts (100.85-108.96% after 4h) and simulated gastric fluid (74.16-80.13% after 3h). Three LAB isolates (1, 3 and 13) with high antimicrobial activity against all foodborne pathogens and probiotics characteristics were subjected to 16S rRNA sequencing and identified as Enterococcus faecium strains. Enterococcus spp. exhibited milk coagulation potential, amylolytic activity, susceptibility to antibiotics and no evidence of hemolysis. Enterococcus spp. isolated from goat milk showed probiotic and technological characteristics and can be used as a starter culture after further safety evaluation.

Isolation, Incidence and Molecular Characterization of Drug-resistant Escherichia coli of Goat Milk

Background: Goat milk is recognized for its high nutritive profile. The practise of antimicrobials in feeding of animals produces resistance in bacteria. Therefore, the present study was proposed to study the incidence of drug-resistant E. coli from raw goat milk samples and investigate the genes responsible for the resistance. Methods: A total of 250 raw milk samples were obtained from different farms of Taif province, Saudi Arabia. Collected samples were cultured on MacConkey agar. Morphological and biochemical tests were achieved for the identification of isolates. Antimicrobial resistance pattern of E. coli was estimated by the disk diffusion method. The resistance genes tet(A) and tet(B), ere(A), aadA1, blaSHV, aac(3)-IV, sul1, catA1 and cmlA, were examined by PCR. Results: Results of the present study showed that out of the 250 samples examined, 100 (40%) were found to be infected with E. coli. Antimicrobial resistance profile evaluated showed a higher resistance against ceftriaxone (90 %) and ticarcillin (86%), followed by amikacin and cefotaxime (87%), and augmentin and penicillin (85%). Lower percentage was observed for gentamicin (58%), ampicillin (66%), bacitracin (75%) and imipenem (32%). Furthermore, multi-drug resistance was observed in most of the isolates. Among E. coli isolates, 86% gave positive amplicons for the blaSHV gene followed by tet(A) and tet(B) genes (85%). Conclusion: The results suggested a probability of possible public health risk of multi-drug resistance of E. coli strains collecting from raw goat milk samples. Consequently, appropriate handling of goat milk processing is significant to prevent E. coli infection.