Diarrheal diseases account for approximately 2 million deaths annually in children under the age of 5years. Disease and death caused by diarrhea is a global problem, but is especially prevalent in developing countries. The aim of the present study is to determine the possible role of E.coli mainly Enter pathogenic (EPEC) serogroup (O111, O55, O26, O86, O119, O127, O114, and O142) and Enteroinvasive E.coli (EIEC) serogroup (O124); Giardia lambleia and Entamoeba histolytica co infections in pathology of acute diarrhea among children's of Baghdad governorate. A total of one hundred seventy presented with diarrhea that proved through clinical investigation were enrolled in this study. After microbiological examinations, Sixty four children that infected with two pathogens were selectively enrolled in this study. The minimum age of infected children was 4 months while maximum age was 116 months. Thirty four (53.1%) % out of Sixty four children were males and females represent the rest 30(46.9%). Stool samples of patients were submitted for direct microscopical examination for detection of G.lamblia and E.histolytica using wet preparation technique. Gram staining technique was applied for demonstration of gram negative bacilli. Stool culture was done using MaCconky agar for determination of E.coli. API 20E system was used for biochemical characterization of E.coli .serogrouping of E.coli was done by direct slide agglutination technique in to four types (type1 EPEC serogroup ( O111,O55,O26 ), type 2 EPEC serogroup ( O86,O119,O127), type3 EPEC serogroup ( O125,O126,O128 ), type 4 EPEC/EIEC serogroup ( O114,O124,O142 ) using Specific trivalent antisera.
In this study the critical age groups were (4-20)month followed by (21-37) month and (38-54) which represent (31.25%) , (28.12%) and (25%) of infected cases . on the other hand the age group (106-122) month was consider less critical age of infection with diarrhea causative agents. Among the age group (4-20) month, infection with E.histolytica represent (21.87%) while infection with EPEC serogroup (O86, O119, O127)represent (12.5%) out of 64 infected children. infection with G.lamblia represent (6.25%) while at this age group the low detectable frequency of infection was caused by EPEC /EIEC serogroup (O114, O124, O142), (3.12 %) with no detectable frequency of infection with EPEC serogroup ( O111,O55,O26)and EPEC serogroup (O125, O126, O128). Regarding age group (21-37) month high frequency (25%) of infection with E.histolytica was recorded compared with (6.25%) for EPEC serogroup (O86,O119,O127), and EPEC /EIEC serogroup ( O114,O124,O142 ). low detectable frequency (3.12%) of infection was caused by G.lamblia .At the age group (38-54) month high frequency of infection with E.histolytica was recorded (18.75%) compared with (3.12%) for EPEC /EIEC serogroup ( O114,O124,O142 ), G.lamblia . Equal frequency of infection was recorded for EPEC /EIEC serogroup (O114, O124, O142) and G.lamblia (6.25%) in the age group (55-71) month as well as for E.histolytica (6.25%) in the age group (72-88) month and (3.12%) in the age group (106- 122) month . E.histolytica was more frequent pathogen that detected in (75%) of diarrheal cases followed by EPEC serogroup (O86, O119, O127), (21.9%), EPEC /EIEC serogroup (O114, O124, O142) and G.lamblia (18.8%) for each one. This study revealed that co infection with EPEC serogroup (O86, O119, O127) and E.histolytica represent (15,62%),while co infection with EPEC / EIEC serogroup ( O114,O124,O142) and G.lamblia represent (9.73%).on the other hand co infection with EPEC / EIEC serogroup (O114,O124,O142)and E.histolytica represent (9.73%).This study revealed that there was positive linear relationship between age of infected children and infection with EPEC serogroup (O86, O119, O127) (r=.367;p=.039. strong negative linear relationship between EPEC / EIEC serogroup ( O114,O124,O142 ) and E.histolytica infection( r= -.462;p=.008) as well as between G.lambelia and E.histolytica infection (r=-.832;p=.000) .This study concludes that there is a possible correlation between O-antigen Serogrouping and coinfection with EPEC / EIEC, EPEC, G.lambelia and E.histolytica.