The Bacterial Aetiology Of Gastroenteritis In Parts Of The Former East Central State Of Nigeria

Abstract

Between September 1981 and December 1982, 1,744 sinlge stool specimens collected from people of all ages suffering from diorrhoea, who were seen as out-patients or admitted into some of the hospitals in Anambra and Imo states of Nigeria, were investigated to determine the bacterial aetiology of thei disease. During thesame period, 683 single stool specimens collected from patients seen as out-patients or admitted into these hospitals with diagnosis other than diarrhoea were also investigated for the presence of these bacteria. 217 environmental samples were investigated to identify the natural reserviors of the pathogenic bacteria. From the diarrhoea patients, Entheropathogenic E.coli were detected in 12.02% (122/1015) of children under 5 years of age examined. Salmonella sp. in 2.7% (47/1,744), Shigella sp. in 1.9% (33/1,744), Campylobacter jejuni in 3.3% (55/1,744), Verginia enterocolitica in 0.5% (9/1,744), Vibro parahaemolyticus in 1.1% (20/1,744) and Vibro cholerea in none(0/1,744). Thus, aetiologic agents were identified in 16.39% of the cases. Enteropathogenic Escherichia coli and Campylobacter jejuni were detected in 2.7% and 1.9% respectively of the control stools and swabs. Epidemiological studies showed that all the surface water investigated were grossly polluted with faecal matter. Two Salmonella sp - S.colindale and S.agama were isolated from the snails. These serotypes were also isolated from diarrhoeal patients in the area. Campylobacter jejuni and Vibro parahamolyticus were also isolated from the environmental sources although the environmental isolates of Vibro parahaemolyticus were all Kanagawa negative whereas the human isolates were Kanagawa positive. The peak months of diarrhoea were June and July for all the age groups examined, and for children less than 5 years of age, December and January were peak months of infection in addition. The commonest EPEC serotype isolated was 0111 k58 (B4) (34 strains). This was followed by 0127 k63 (B8), 026 k60 (B6) and 0125 k70 (B15) - (32 strains, 24 strains and 15 strains respectively) , the frequencies of others were eight or less. Of the 53 strains examined for enterotoxin production and enteroinvasiveness, 2(3.8%) were found to produce both heat-labile (LT) and heat-stable (ST) enterotoxins, 6(11.3%) produced (LT) only, 4 (7.5) produced (ST) only and 6(11.3%) were invasive. Shiegella boydii was the most frequent Shigella Sp. isolated (45.5%). This was followed by Shigella dysenteriae and Shigella sonnel (39.3%) and (15.2%) respectively, indicating that Shigella flexneri infection was rare of the period of investigation. Thirth one of the 47 Salmonella isolates were Salmonella isangi, nine were Salmonella agama, four were Salmonella ekotedo, two were Salmonella colindale and one was Salmonella infantis. The Yersinia enterocolitica were serolocically ungroupable. The isolates were examined for drug resistance by Bauer-Kirby method, and the drugs used were ampicillin, tetracycline, kanamycin, streptomycin, trimethoprin/sulfamethoxazole, chloramphenicol and gentamicin. Multiple drug resistance was observed in all the isolates except Salmonella Species. The minimum inhibitory concentrations of the antibiotics for the organisms were tested and gentamicin proved to be the best drug for all the isolates while tetracycline was the worst. One strain of the enteropathogenic E. coli (E3) R-type (ATKS.Sxt) is resistant to ampicillin, tetracycline, kanamycin, streptomycin and trimethoprim/sulfamethoxazole, and a strain of Yersinia enterocolitica (Y4) R-type (ATSC,Sxt) were assessed for their ability to transfer antimicrobial resistance by conjugation to a recipient strain of E. coli k12 and to a recipient strain of Salmonella isangi. Resistance was transferred from E3 to the recipients but not from Y4 to the recipients. Transfers were better at 370C than at 280C. Most of the enteropathogenic serotype of E. coli including E3 demonstrated multiple plasmid bonding patterns. Only one of the bands in E3/E.coli k12 transconjugant correlated with drug resistance transferred from E3 to the E. coli K12 recipient. Y4 demonstrated a DNA strand without plasmids (bands). Plasmids of varied molecular weights ranging from 1.2 to 105x106 daltone were isolated.