https://imcjms.com/public Ibrahim Medical College Journal of Medical Science https://imcjms.com/public/registration/journal_full_text/120 Mon, 31 Oct 2016 10:37:33 +0000 Ibrahim Med. Coll. J. 2008; 2(2): 40-43 Key Words: EPEC, diarrhea, serotyping, Malaysia Introduction Enteropathogenic Escherichia coli (EPEC) is a leading cause of acute diarrhea among children in developing countries. It accounts for about 7-23% of all diarrhea pathogens.1-4 EPEC attaches to the brush border of the mucous membrane of the small intestine in a characteristic manner, producing ultra structural changes known as attachment effacement (AE) lesions.5 The AE lesion is mediated by intimate attachment of bacteria to the apical enterocyte causing localized destruction of brush border microvilli and perhaps thereby mediating increased secretion.3 The laboratory counterpart of muscosal colonization is adherence of EPEC to cells such as HEp-2 and HeLa cells. E. coli exhibiting localized adherence (LA), diffuse adherence (DA), aggregative adherence (AA) and localized adherence-like (LAL) patterns with HEp-2 or HeLa cells has been implicated as diarrhreal pathogens.6,7 Among the three phenotypes, LA is highly correlated with classic EPEC serotypes. However, studies have demonstrated that E. coli exhibiting DA pattern should be considered enteropathogenic as 38.2% of isolated E. coli from diarrhea cases exhibited DA in HEp-2 cell compared to 8-9% of controls.2 Fluorescence actin staining (FAS) test was reported for the identification of E. coli causing the AE lesion.8 Recently, it has been shown that cortactin isnecessary for organizing actin pedestals in responseto EPEC in HeLa cells.9   Study population Stools or rectal swabs were obtained from children below 5 years of age attending HUSM with acute diarrhea. HUSM is located in Kota Bharu, Kelantan, the northeastern state of Malaysia. Acute diarrhea was defined as four or more loose stools a day, with or without abdominal pain and fever for at least one day. The duration of the episode should be less than ten days.10 Age matched healthy children without history of diarrhea one month prior to the date of enrollment in the study was included as control. Microbiological methods   In this study, 60 stool samples or rectal swabs were collected from children with acute diarrhea while 16 samples were taken from age matched healthy children without diarrhea as control. Out of 60 diarrhea cases, 36 (60%) were below 2 years of age. EPEC serotype was isolated from 14 (23.3%) diarrhea cases by serotyping (Table 1). Nine different serotypes of EPEC were isolated and the most prevalent strain was 0125:K70 by serotyping (28.57%). Only one EPEC (6.25%) was isolated from healthy control children. Table-1:  Rate of isolation of EPEC from diarrhea cases (n=60) by serotyping Total  No. positive (%) No. positive 5 (8.3) 0111:K58(B5) O126:K71(B16) 1 2 6 (10.0) O125:K70(B15) 1 1 3 (5.0) O124:K72(B17) 2 14 (23.3)   Note:  Only one EPEC was detected out of 16 control subjects (6.25%) by EPEC antisera (Polyvalent 4)   Table 2 shows the results of HeLa and HEp-2 cell adhesion assay of E. coli isolated from diarrhea and control cases. Out of 60 diarrhea cases, 30.0% and 26.6% showed one or other adherence pattern with HeLa and HEp-2 cells assay respectively. The comparative figures for the control were only 12.5% and 6.25% respectively. Diffuse adherence (DA) pattern was predominant in both HeLa and HEp-2 cell assay systems. Out of total strains positive by cell adherence assay, 81.25% and 88.88% exhibited DA pattern by HEp-2 and HeLa cell respectively. Table-2: Results of HeLa and HEp-2 cell adhesion assay of E. coli isolated from diarrheal and control cases Diarrhea cases(n=60) No.positive in HEp-2 cells (%) No.positive in HEp-2 cells (%) Diffuse adherence 16 (26.66) 2 1 (1.66) 0 Aggregative adherence 1 (1.66) 0 16 (26.66) 1 (6.25)   Table 3 shows that about 44.0% of E. coli that was positive in cell adherence assay was negative by EPEC antisera. The single EPEC isolated from control case did not show any adherence pattern with HeLa or HEp-2 cells assay. Table-3: Relationship of cell adherence assay and serotyping by EPEC antisera Total Positive No. Positive by EPEC antisera (%) HEp-2 Cells 9 (56.3) HeLa Cells 10 (55.6)              were negative by HEp-2 and HeLa cell assays respectively.     1.    Levine MM. Escherichia coli that cause diarrhea: enterotoxigenic, enteroinvasive, enterohaemorrhagic, and enteroadherent. J Infect Dis 1987; 155: 377-389. 3.    NM Thielman: Enteric Escherichia coli infections. Current Opinion in Infectious Disease 1994; 7:        582-591. 5.    Echeverria PK, Serichantalerg O, Changchawalit S, Baudy B, Levine MM, Orskov F, Orskov I. Tissue culture adherent Escherichia coli in infantile diarrhea. J Infect Dis 1992; 165: 141-143. 7.    Nataro JP, Kaper JB. Diarrheogenic Escherichia coli. Clinical Microbiology Review 1998; 11: 142-201. 9.    Vlademir V, Cantarelli A, Takahashi I, Yanagihara Y, Akeda K, Imura T, Kodama G, Kono Y, et al. Cortactin is necessary for f-actin accumulation in pedestal structures induced by enteropathogenic Escherichia coli infection. Infection and Immunity 2002; 70: 2206-2209. 11.  Edward PR, Ewings WH. Identification of enterobacteriacae, 3rd edition. Minneapolis, Burgess Publishing Co. 1972. 13.  Kaper JB. Defining EPEC. Review of Microbiology 1996; 27:130-133. 15.  Gomes TAT, Blake PA, Trabulsi LR. Prevalence of Eschericia coli strains with localized, diffuse and aggregative adherence to HeLa cells in infants with diarrhea and matched controls. J Clin Microbiology 1989; 27: 266-269. 2026 Ibrahim Medical College. All rights reserved.