Epidemiology of Shiga toxin-producingEscherichia coliO157:H7 in Africa in review

Abstract

Shiga toxin-producing Escherichia coli (STEC) O157:H7 is responsible for intestinal and extra-intestinal disease syndromes in human. Isolation of the pathogen from animals, food, clinical samples and environment has been reported from all continents. A review of STEC O157:H7 in Africa from a structured literature search of the PubMed electronic database is presented. It describes the epidemiological status of the pathogen on the aspects of source, transmission, pathogenesis, disease syndromes, diagnosis, disease burden and the challenges in treatment and control strategies. About a quarter of African countries have reported isolation of STEC O157:H7 either from humans, animals, food or the environment. Different methods have been used in detection of the pathogen. Most reported human infections do not show temporal relationships with reports of isolation of the pathogen from other sources such as animals, water or food. Lack of a direct link between isolates from humans and other sources makes it difficult to point out incident specific determinants and direction of transmission. The aim of this review is to give an insight into the features of STEC O157:H7 infection in Africa and draw the attention of various stakeholders to the public health threat of the pathogen for possible interdisciplinary and multi-sectoral joint efforts in the control strategies.

Quantitative microbial risk assessment for waterborne pathogens in a wastewater treatment plant and its receiving surface water body

“…In another study on E. coli O157:H7 that included an investigation of 180 drinking water samples from the Amathole District in South Africa, only 4 (2.2%) were confirmed to be positive using molecular techniques [33]. The detection of E. coli O157:H7 in all the sampled sites in the present study, albeit at very low prevalence (5.2%), is consistent with the generally low occurrence of the organisms in environmental samples in South Africa [34].…”

“…All the detected OH157: H7 strains were, however, stx negative. Reports on the isolation of O157:H7 are rare in South Africa, particularly from environmental samples [33,34] . Muller et al [35] used immunomagnetic separation (IMS) in combination with selective media and other techniques to evaluate the incidence of E. coli O157:H7 in sewage and environmental water samples in Gauteng South Africa.…”

Occurrence of multi-drug resistant Escherichia coli and Escherichia coli O157:H7 in meat and swab samples of various contact surfaces at abattoir and butcher shops in Jimma town, Southwest district of Ethiopia

“…Escherichia coli are a member of the family Enterobacteriaceae, and are normal inhabitants of the gastrointestinal tract of animals and humans. Some strains, such as shiga toxin-producing enterohaemorrhagic E. coli (EHEC) O157:H7 is the predominant and most virulent serotype associated with bloody and non-bloody diarrhea, haemorrhagic colitis and haemolytic uremic syndrome (HUS) [1,2]. Ruminants are said to be reservoirs, whereby cattle are regarded as principal sources of infections.…”

Prevalence ofE. coliO157:H7 strains in irrigation water and agricultural soil in two district municipalities in South Africa

“…Shiga-toxin (Stx) is the major virulence determinant of E. coli O157:H7 and promotes the extensive damage of the intestinal lining leading to diarrhoea. This toxin is further divided into Stx 1 and Stx 2, coded by the stx1 and stx2 genes which causes the haemorrhagic uraemic syndrome (HUS) [3]. STEC O157:H7 poses a great danger to the health of humans owing to its high virulence potential, low infectious dose , persistence in the environment and resistance to treatment options [3].…”

“…This toxin is further divided into Stx 1 and Stx 2, coded by the stx1 and stx2 genes which causes the haemorrhagic uraemic syndrome (HUS) [3]. STEC O157:H7 poses a great danger to the health of humans owing to its high virulence potential, low infectious dose , persistence in the environment and resistance to treatment options [3]. Clinical syndromes produced by E. Coli O157:H7 range from slight intestinal distress to HUS, end-stage renal disease (ESRD), and death [4].…”