Phenotypic Profiles of Enterotoxigenic Escherichia coli Associated with Early Childhood Diarrhea in Rural Egypt

Abstract

Enterotoxigenic Escherichia coli (ETEC) causes substantial diarrheal morbidity and mortality in young children in countries with limited resources. We determined the phenotypic profiles of 915 ETEC diarrheal isolates derived from Egyptian children under 3 years of age who participated in a 3-year population-based study. For each strain, we ascertained enterotoxin and colonization factor (CF) expression, the O:H serotype, and antimicrobial susceptibility. Sixty-one percent of the strains expressed heat-stable enterotoxin (ST) only, 26% expressed heat-labile enterotoxin (LT) alone, and 12% expressed both toxins. The most common CF phenotypes were colonization factor antigen I (CFA/I) (10%), coli surface antigen 6 (CS6) (9%), CS14 (6%), and CS1 plus CS3 (4%). Fifty-nine percent of the strains did not express any of the 12 CFs included in our test panel. Resistance of ETEC strains to ampicillin (63%), trimethoprim-sulfamethoxazole (52%), and tetracycline (43%) was common, while resistance to quinolone antibiotics was rarely detected. As for the distribution of observed serotypes, there was an unusually wide diversity of O antigens and H types represented among the 915 ETEC strains. The most commonly recognized composite ETEC phenotypes were ST CS14 O78:H18 (4%), ST (or LTST) CFA/I O128:H12 (3%), ST CS1؉CS3 O6:H16 (2%), and ST CFA/I O153:H45 (1.5%). Temporal plots of diarrheal episodes associated with ETEC strains bearing common composite phenotypes were consistent with discrete community outbreaks either within a single or over successive warm seasons. These data suggest that a proportion of the disease that is endemic to young children in rural Egypt represents the confluence of small epidemics by clonally related ETEC strains that are transiently introduced or that persist in a community reservoir.

Comparison of virulence markers and antibiotic resistance in enterotoxigenic Escherichia coli isolated ten years apart in Tehran

“…In Egypt, the rate for CFA/I was reported as 9.7% in 2004, increasing to 15.6 % in 2009; for CFA/II, the rate was 7.3%, changing to 1.8%, and the CFA/IV rate increased from 12.6% in 2004 to 17.2% in 2009. More than half (59% and 53%) of the ETEC isolates in this region were not associated with any known CFs [20,2]. In this study, the prevalence of the CF types also showed variation between the two groups isolated 10 years apart, with CFA/I, CS4, CS5 and CS6 (CFA/IV)being the most common MAbidentified CFs (Table 3).…”

“…Katouli et al showed that ST-only with a 78% rate was the most frequent toxin type followed by LT-only (14%) and LTST (8%) [19]. Dominance of the ST-expressing ETEC has been documented in Egypt, Bangladesh, and Tunisia [11,20,21]. However, a recent study conducted in Bangladesh concluded that ETEC strains have shifted from ST-producers to significantly more LTproducing strains similar to those observed in Latin American countries, such as Mexico, Peru, and Argentina, which have shown a high prevalence of LT-producing ETEC [22,11,23].…”

“…DIGlabeling the PCR products using labeled primers has made this phase much easier and faster than labeling the PCR product by random hexamer or even PCR labeling kits, and DIG-labeled probes can be stored at -20°C for at least a year [12]. High resistance to antibiotics, especially ampicillin, trimethoprim/sulfamethoxazole (SXT), streptomycin, chloramphenicol and tetracycline, has been reported in recent studies dealing with both human and avian E. coli isolates in Iran [24,25], which follows the global trend [20]. This study showed that, by 1998, resistance to quinolones as well as cefalothin was emerging and, by 2008, resistance to cefalothin was reported in 37% of diarrhoeagenic E. coli [24].…”

Enteroaggregative Escherichia coli in diarrheic children in Egypt: molecular characterization and antimicrobial susceptibility

“…High frequency of resistance to antimicrobial agents among DEC isolated from children with diarrhea has been reported from several developing countries [3,4]. With the exception of ETEC [5], there little information published on the susceptibility of DEC from Egypt to antibiotics.…”

“…Few studies have examined the clinical relevance of ETEC-associated diarrhea in Egypt [5,6]. However, there is little information on the role of EAEC in pediatric diarrhea in the country.…”