Characteristics of Strains of Escherichia coli Isolated from Locally-Fermented Milk (“Nono”) in Zaria, Nigeria

Abstract

Of a total of 200 fermented milk (“Nono”) samples collected, 79 (40%) were positive for Escherichia coli, all isolates being of fecal origin. The mean pH was 4.41 and the values ranged from 4.03 to 4.81. Thirty-three (42%) isolates produced alpha hemolysin while two (3%) had beta hemolytic pattern. Eight (26%) of 31 randomly selected isolates produced heatlabile (LT) enterotoxin as detected by the rabbit ileal loop test. On testing the susceptibility of 50 isolates to antimicrobial agents, resistance was high to nitrofurantoin (100%), furadantoin (98%), Co-trimoxazole (98%), tetracycline (90%), and sulphafurazole (98%). Only 17 (34%) and 16 (32%) isolates were resistant to gentamycin and colistin sulfate, respectively. It was concluded that E. coli of fecal origin in “nono” could be a health risk as gastro-enteritis may result. Furthermore, the presence of other enteric pathogens cannot be ignored.