Studies on the Extra-Human Distribution of Enterohaemorrhagic Escherichia Coli From Borno and Enugu States of Nigeria

Abstract

Enterohaemorrhagic Escherichia coli (EHEC) a causative agent of haemolytic uremic Syndrome (HUS) and haemorrhagic colitis especially in children, believed to originate from cattle is increasing with the day in parts of Nigeria. In order to ascertain the probable sources to assist a control regimen, laboratory analysis was carried out using standard bacteriological techniques for the isolation and identification of Escherichia coli (E.coli) and EHEC.A study was done on the distribution of EHEC in extra-human materials in Borno and Enugu States of Nigeria. A total of 560 fresh samples were collected and investigated for the study between May 2011 and June 2012 with 280 samples from each zone comprising of 20 pieces of cow offal/intestines, 40 pieces of grilled and spiced cow (suya) meat and 40 samples each of abattoir slabs swabs, cow dung, and water. Also, five vegetable samples made up of 20 samples each of Pumpkin leaves (Pelviaria occidalis), Edible green leaves (Amaranthus hybridus), Garden eggs (Solanum melongela),White cabbages(Brassica capitata) and Lettuce(Lactuca sativa) were also analyzed. From results obtained, of the total 280 samples analyzed in Enugu, 113(40.4%) yielded E.coli of which 21(7.5%), were EHEC. Whereas, that of Borno, 180(64.3%) yielded E.coli of which 42(15.0%) were EHEC. Generally, of a total of 280 samples studied from Enugu, 113(40.4%)were E.coli of which 21(7.5%) were EHEC 0157:H7;with a prevalence rate of 7.5%. Of the total 21(7.5%) EHEC isolated from the 280 samples analyzed from Enugu;abattoir slabs swabs 5(23.8%)yielded the highest, followed by water samples from streams in the area with 4(19.0%) isolates. This was closely followed by Grilled cow meat (suya), Cabbages, and Lettuce which bracketed at 3(14.3%) respectively, while Pumpkin leaves, Garden eggs, and Edible green leaves each yielded 1(4.8%) EHEC. There was however no statistically significant differences between the number of EHEC isolated from the individual samples analyzed using Pearson Chi-square test.(P>0.05).For the E.coli isolated from each of the 280 extra-human samples from Enugu analyzed, also using the Pearson-Chi square test, there was a statistically significant difference in the numbers of E.coli isolated from each of the samples analyzed (P<0.05).For the Borno State, 280 total extra-human samples studied yielded a total of 180(64.3%) E.coli of which 42(15.0%)were EHEC strains with a prevalence rate of 15%.The isolation rates of EHEC from the 280 extra-human samples analyzed from Borno, a total of 42(15.0%)EHEC strains were isolated with Cow dung 7(16.7%),ranking highest in isolation rates, followed closely by ow offal, abattoir slabs swabs, and Water samples which yielded 5(11.9%)EHEC respectively. Grilled cow meat (suya),Cabbages and Lettuce yielded 4(9.5%),EHEC each. There was however no statistically significant differences in the isolation rates for EHEC strains from the various samples analyzed from Borno (P>0.05),though the differences in the E.coli numbers isolated from the same zone was statistically significant using the Pearson Chi square test (P<0.05). We have more EHEC infected vegetables in the dry season because of manure(cattle dung )used to fertilize the vegetable garden whereas, during the raining season we have more EHEC infected meat associated samples because of rains washing faecal material from man and animals into grazing land, farm land and water sources.