Bacterial enteropathogens and factors associated with seasonal episodes of gastroenteritis in Nsukka, Nigeria

Abstract

Each year, between April and October, many children of school age and some young adults in Nsukka, Nigeria suffer from gastroenteritis. The period covers the rainy season in this part of Africa, when manured farmland occasionally is flooded. In view of the number of people suffering diarrhoea and occasionally low-grade fever, it became necessary to investigate the nature of the bacterial agents responsible. Between April and October (1996-1998), 500 loose or watery stools were collected from patients, the ages of which ranged from one month to 31 years. Stools that contained parasites were excluded from the study. Samples were cultured on 5% blood agar and 1% egg-yolk agar (both containing 10 microg/mL ampicillin), MacConkey agar, Shigella Salmonella agar and in alkaline peptone water. Bacterial growths were identified using standard bacteriological procedures. Drinking water and some fruit and vegetables prevalent during this period of the year also were cultured. Of the 500 stool samples tested, 138 (27.6%) grew a range of organisms including Aeromonas hydrophila (65 [13%]), Salmonella spp. (55 [11%]), Shigella spp. (9 [1.8%]) and enteropathogenic Escherichia coli (9 [1.8%]). Drinking water and some vegetables grew Pseudomonas aeruginosa and Enterococcus faecalis, respectively. The highest isolation rate occurred during June and July, corresponding to the period of greatest flooding of arable land. Although no enteropathogens were isolated from the fruit and vegetables examined, they contained E. faecalis--an organism found in faeces. Our findings failed to explain why 72% of the samples grew no bacterial enteropathogens.

The GenusAeromonas: Taxonomy, Pathogenicity, and Infection

“…In industrialized countries, regardless of patient populations studied, the frequency of Aeromonas in stool samples ranges from 2.2% to 10% (72). Similar findings have also been posted from non-European or American surveys, including a low prevalence of 0.62% in Malaysian children in an urban setting (184) and a high incidence of 13% in a Nigerian community with poor personal and environmental hygiene standards (227). There have been few prospective and no population-based studies involving Aeromonas gastroenteritis to date.…”

Clinical relevance of Aeromonas sM503

“…Aeromonas was the most common enteropathogen after Salmonella and Campylobacter [33]. While in studies in which Campylobacter was not investigated Aeromonas prevailed over Salmonella and Shigella, as in the Nigerian study [34], in many studies Aeromonas was more prevalent than enteropathogenic E. coli [33,34].…”

“…In the most recent studies that have evaluated the microbes involved in acute childhood diarrhoea they indicate incidences of Aeromonas in relation to the total cases studied ranging from 2.3% in Taiwan to 13% in Nigeria [32][33][34]. Aeromonas was the most common enteropathogen after Salmonella and Campylobacter [33].…”

Diarrheagenic Escherichia coli in sub-Saharan Africa: Status, Uncertainties and Necessities

“…A Tanzanian study found that screening for diarrheagenic E. coli increased the proportion of cases for which a pathogen could be identified by 34.6% in the dry season and 28% the rainy season to over 70% overall [21]. Conversely, studies that have failed to seek more than one class of diarrheagenic E. coli have often reported low rates of pathogen recovery [22].…”