Diarrhoeagenic E. coli and Associated Virulence Factors on Bioko Island, Equatorial Guinea

Among the various aetiological agents causing acute diarrhoeal disease (ADD), the heterogeneous group of different pathotypes of Escherichia coli continues to be responsible for a high percentage of cases, especially in children under 5 years of age in middle and low-income countries in Latin America, Asia and Africa. The aim of the present study was to identify the main pathotypes of E. coli associated with ADD in patients in the two main hospitals on Bioko Island, Equatorial Guinea (November 2011-April 2012). A total of 716 clinical samples were analysed, 496 samples from patients with symptomatology compatible with ADD (symptomatic) and 220 from patients without symptomatology compatible with ADD (asymptomatic). Of the samples from symptomatic patients, 41.53% were positive for a diarrhoeagenic E. coli pathotype while only 1.36% of asymptomatic patients were positive for a diarrhoeagenic E. coli pathotype. The most affected age group was children aged 0-4 years (37%). The ECD groups identified in symptomatic patients were: 22.98% enteroaggregative E. coli (EAEC); 9.68% enterotoxigenic E. coli (ETEC); 6.45% enteropathogenic E. coli (EPEC) and 2.42% enteroinvasive E. coli (EIEC). In asymptomatic patients, only three cases of ECD due to ECEA (0.90%) and ECEP (0.45%) were detected. In our study no verotoxigenic E. coli pathotype was detected in a single case. The results suggest that EAEC, ETEC, EPEC and EIEC pathotypes are important aetiological agents of ADD on Bioko Island, Equatorial Guinea. The results highlight the need to develop appropriate diagnostic methods for this group of pathogens. Improved diagnostic capacity coupled with implementation of prevention and control measures could help reduce the number of ADD caused by DEC in Equatorial Guinea.