ISOLATION AND CHARACTERIZATION OF Escherichia Coli 0157: H7 IN STOOL SAMPLES

ABSTRACT

Escherichia coli serotype 0157:H7 is a recently recognized human pathogen associated with heamorrhagic colitis. This study aimed at isolating Escherichia coli 0157:H7 from the stool sample of children age 0- 5 years. A total of 200 stool samples were collected and analyzed using standard microbiological techniques. Presumptive Escherichia coli 0157:H7 were confirmed serologically using Escherichia coli 0157:H7 latex agglutination test. Antimicrobial susceptibility was carried out on test isolates following Clinical Laboratory Standard Institute (CLSI) guidelines using modified Kirby- Bauer disc diffusion method. Virulence genes of Escherichia coli 0157:H7 were detected using Polymerase chain reaction (PCR) method. Of the 200 stool samples analysed, 122 (61%) yielded growth of Escherichia coli of which 13 (6.5%) were Escherichia coli 0157:H7 presumptively. Serotyping of the presumptive isolates comfirmed 3(1.5%) as Escherichia coli 0157:H7. Stx2 gene was detected in 2 (1%) isolates. The confirmed Escherichia coli 0157:H7 showed 100% sensitivity to gentamicin, ofloxacin and levofloxacin. There was significant association between Escherichia coli 0157:H7 infection and non- covering child’s feeding utensils as (p = 0.0467) and child’s eating habit (p = 0.0168). Thus it is suggested that routine diagnosis of Escherichia coli 0157:H7 should be incorporated in the management of heamorrhagic colitis.