Prevalence, virulence genes and Antimicrobial Resistance of Shiga-toxigenic E.coli in diarrhoea patients from Kitale, Kenya

Too J.R.,Ngari M., Kikuvi G.M., Matey E.J., Koima J., ChebiiJ.,Wanzala P., Kiptoo M.K., Githui W.A., Sang W.K.

Too J.R[1,6].,Ngari M[2]., Kikuvi G.M[6]., Matey E.J[1]., Koima J[4]., ChebiiJ[4].,Wanzala P[7]., Kiptoo M.K[5]., Githui W.A[3]., Sang W.K[1].

  1. Kenya Medical Research Institute Centre for Microbiology Research (CMR)
  2. Kenya Medical Research Institute, Centre for Geographic Medicine Research-Coast (CGMRC), Kilifi, Kenya.
  3. Kenya Medical Research Institute Centre for Respiratory Diseases Research (CRDR)
  4. Kitale County Referral Hospital (KCRH)
  5. South Eastern Kenya University, (SEKU)
  6. Jomo Kenyatta University of Science and Technology (JKUAT)
  7. Kenya Medical Research Institute Centre for Public Health Research (CPHR)

Corresponding Author: Rael Too P.O. Box 2592 Eldoret, Kenya.


Introduction: Shiga toxin-producing Escherichia coli (STEC) are among the most important causes of food-borne diseases. They cause illnesses ranging from mild diarrhea to more severe conditions that may progress to hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). The burden of STEC in patients with diarrheal illness in Kitale county referral hospital, Trans-Nzoia County had not been established.

Objectives: To determine the prevalence of STEC, its associated virulence genes and antimicrobial resistance among patients seeking treatment for diarrhoeal illness at Kitale County Referral Hospital.

Methods: Stool samples from patients seeking treatment for diarrheal illness and had consented to participate in the study were collected and cultured for enteric bacteria.

Suspect E.coli isolates were further identified using conventional biochemical methods. Conventional multiplex PCR targeting Shiga toxins (stx1, stx2, hlyA and attaching and effacing mechanisms (eaeA) were used to detect STEC virulence markers responsible for the Pathogenicity of STEC infection among other E.coli pathotypes.

Results: A total of 295 participants were enrolled; median age 120 months (IQR: 36-312). 39 %( 115) were children aged <5yearsof whom 54% (160) were females. The prevalence of pathogenic E.coli was 19%56/295 and STEC was the most prevalent among E.coli pathotypes at5.4%16/295.The Stx2 gene and the Stx1/Stx2/hlyAcombination were the most prevalent in the STEC strains. The virulence genes (Stx1, Stx2, eaeA* and HlyA*)were observed in 13, 19, 9 and 14 in STEC isolates respectively.The most common gene was Stx2 and combinations of (Stx1+Stx2+hlyA)genes. Antimicrobial resistance to commonly prescribed antibiotics: chloramphenicol, ampicillin 10µg, erythromycin15µg, gentamicin10µg, ciprofloxacin 5µg, tetracycline 30µg, Trimethoprim/Sulfamethoxazole 25 µg, Cefotaxime 30 µg, furazolidine (8µg) and nalidixic acid 30 µg. were observed for all E.coli isolates except one (1.8%; 95% CI=0.1-9.6%). No isolates among STEC showed resistance to Furazolidine drug. However, Trimethoprim / Sulphurmethoxazole) was the drug which exhibited the highest resistance at (94%, 95% CI 70 to 99%).

Conclusion and recommendation: Prevalence of STEC was 5.4%, (Stx1/Stx2/hlyA) virulence genes combination was the most common. High resistance to commonly prescribed antibiotics were observed in E.coli isolates and may be an existing problem that needs to be further research investigation.

Key words: Shiga-ToxigenicEscherichia coli (STEC), antimicrobial resistance, Kitale County referral hospital.

[Afr J Health Sci. 2017; 30(2):105-119]

Login Required

Leave a Reply