Characterization and antimicrobial susceptibility pattern of Diarrheagenic E. coli in Thika Level 5 Hospital

Abstract

Diarrheagenic E. coli (DEC) are among re-emerging bacterial strains associated with outbreaks of severe diarrhoea and multiple drug resistance. Our objectives were to characterize DEC among diarrheal patients attending Thika Level 5 Hospital and determine their antimicrobial susceptibility patterns. A cross-sectional study was conducted. Consenting patients of all ages seeking diarrhoea treatment at the hospital from April to July 2014 were recruited. A structured questionnaire was used to collect clinical and epidemiological information. Stool samples were collected, inoculated on bacterial differential media for growth of enteric pathogens and antimicrobial susceptibility patterns of DEC isolates determined. Isolates were characterized by Polymerase Chain Reaction for the presence of virulence properties. A total of 402 stool samples were cultured. E. coli was isolated from 269, of which 72 (27%) were DEC; 60 (83.3%) enteroaggregative E. coli (EAEC), 6 (8.3%) enteropathogenic E. coli (EPEC) and 6 (8.3%) enterotoxigenic E. coli (ETEC). Of the DEC affected patients, 58% were female, median age was 8 (IQR: 2-28) years, 75% did not boil water and 100% did not treat water. Twenty five (35%) patients with DEC were under-five years of age. Drinking un-boiled water (OR: 2.51, 95% CI: 1.36-4.61) was associated with having DEC. Being under-five years was associated with EAEC (P<0.05). Of the 60 EAEC strains, 24 (40%) EAEC isolates were positive for both aggR and aspU genes, while 36 (60%) were positive for aspU gene only. EPEC eae (100%, n=6) and ETEC elt (100%, n=6). All DEC isolates were sensitive to cefoxitin, meropenem, amikacin, gentamicin and ciprofloxacin. They were resistant to ampicillin (92%), trimethoprim-sulfamethoxazole (92%) and amoxicillin-clavulanic acid (85%). Majority of diarrhea patients were female and predominant DEC strain were EAEC. Drinking un-boiled water was associated with DEC infection. High level of resistance to ampicillin, trimethoprim-sulfamethoxazole and amoxicillin-clavulanic acid were observed. All isolates were sensitive to ciprofloxacin and gentamicin.