Enterotoxigenic Escherichia coli (ETEC) in hospitalised Arab infants from Judea area--west bank, Israel

Clonal Spread of Enterotoxigenic Escherichia coli O128:H45 Strain in the Neonate Unit

Enterotoxigenic Escherichia coli (ETEC) has the potential to cause nosocomial infantile diarrhea in a hospital setting. We detected 12 ETEC serotype O128:H45 isolates from diarrheal neonates in our neonatal unit from July through October 2012. These infants developed hospital-acquired and epidemiologically related diarrhea. Pulsed-field gel electrophoresis analysis and multilocus sequence typing of these 12 isolates suggested that a specific clone of ETEC serotype O128:H45-CS21-ST2332 caused nosocomial diarrhea among neonates. Of concern, this ETEC clone strain was resistant to multiple drugs, particularly third-generation cephalosporins.

Phenotypic and genotypic analysis of enterotoxigenic Escherichia coli in samples obtained from Egyptian children presenting to referral hospitals

Hospital surveillance was established in the Nile River Delta to increase the understanding of the epidemiology of diarrheal disease among Egyptian children. Between September 2000 and August 2003, samples obtained from children less than 5 years of age who had diarrhea and who were seeking hospital care were cultured for enteric bacteria. Colonies from each culture with a morphology typical of that of Escherichia coli were tested for the heat-labile (LT) and heat-stable (ST) toxins by a GM-1-specific enzyme-linked immunosorbent assay and colonization factor (CF) antigens by an immunodot blot assay. Enterotoxigenic E. coli (ETEC) isolates were recovered from 320/1,540 (20.7%) children, and ETEC isolates expressing a known CF were identified in 151/320 (47%) samples. ST CFA/I, ST CS6, ST CS14, and LT and ST CS5 plus CS6 represented 75% of the CFs expressed by ETEC isolates expressing a detectable CF. Year-to-year variability in the proportion of ETEC isolates that expressed a detectable CF was observed (e.g., the proportion that expressed CFA/I ranged from 10% in year 1 to 21% in year 3); however, the relative proportions of ETEC isolates expressing a CF were similar over the reporting period. The proportion of CF-positive ETEC isolates was higher among isolates that expressed ST. ETEC isolates expressing CS6 were isolated significantly less often (P < 0.001) than isolates expressing CFA/I in children less than 1 year of age. Macrorestriction profiling of CFA/I-expressing ETEC isolates by using the restriction enzyme XbaI and pulsed-field gel electrophoresis demonstrated a wide genetic diversity among the isolates that did not directly correlate with the virulence of the pathogen. The genome plasticity demonstrated in the ETEC isolates collected in this work suggests an additional challenge to the development of a globally effective vaccine for ETEC.

Phenotypic profiles of enterotoxigenic Escherichia coli associated with early childhood diarrhea in rural Egypt

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.

Prevalence of enterotoxigenic Escherichia coli (ETEC) in hospitalized acute diarrhea patients in Denpasar, Bali, Indonesia

The relationship between enterotoxigenic Escherichia coli (ETEC) and hospitalized patients with acute diarrhea was examined in a study conducted in two hospitals from June 2000 to May 2001 in Denpasar, Bali, Indonesia. A total of 489 hospitalized patients with acute diarrhea were enrolled, and their rectal swabs were screened for enteric bacterial pathogens. Toxins, colonization factor antigens (CFAs), in vitro antimicrobial susceptibility and seasonal distribution patterns associated with ETEC were ascertained. The diagnosis of ETEC infection and CFAs association were performed with GM-1 ELISA and Dot blot immunoassays. Enterotoxigenic Escherichia coli was isolated from the rectal swabs of 14.9% of the patients. The distribution of toxins among the ETEC strains found was ST in 51 (69.9%), while LT and ST/LT were found in 28.8% and 1.3% respectively. The highest isolation rate for ETEC was found among children between the ages of 1 and 15 years. Colonization factor antigens were identified in 28.8% of the ETEC strains. A high prevalence of CFA was found among the rectal swabs of patients with ST isolates. High frequency of resistance to ampicillin, trimethoprim/sulfamethoxazole, chloramphenicol, tetracycline and cephalothin was displayed among the ETEC strains. All ETEC strains were susceptible to norfloxacin, ciprofloxacin and nalidixic acid. The results of this study document the prevalence of ETEC in hospitalized patients with acute diarrhea in Denpasar, Bali, Indonesia. Data generated in this study depicts the prevalence of ETEC diarrhea and CFA types among diarrhea patients in the tourist city of Denpasar, Bali, Indonesia.

Phenotypic diversity of enterotoxigenic Escherichia coli (ETEC) isolated from cases of travelers' diarrhea in Kenya

BACKGROUND

The aim of this study was to characterize phenotypically enterotoxins, colonization factors (CFs) and the antibiotic susceptibility of enterotoxigenic Escherichia coli (ETEC) strains isolated from cases of acute diarrhea that occurred in Europeans traveling to resorts in Mombasa, Kenya; this information is critical for the development of vaccines and empirical treatment.

METHODS

Over a 1-year period from 1996 to 1997, five E. coli-like colonies were obtained from each of 463 cases with acute diarrhea. These strains were characterized for enterotoxins using GM-1 ELISA, for CFs using a dot-blot assay, and for antibiotic susceptibility using antibiotic disks.

RESULTS

Of 164 strains characterized for ETEC phenotype, 30 (18%) expressed heat-labile toxin (LT) only, 83 (51%) heat-stable toxin (ST) only, and 51 (31%) both LT and ST. Analysis for CF expression demonstrated that 107 (65%) of the strains were positive for CFs, including CFA/IV (46%), CFA/II (35%), and CFA/I (5%), while less than 4% expressed less common CFs. All ETEC strains tested were resistant to erythromycin and sensitive to ceftriaxone. Over one-third of the strains were resistant to sulfamethoxazole-trimethoprim or tetracycline. Six strains were resistant to nalidixic acid; none of these were resistant to ciprofloxacin.

CONCLUSIONS

Cumulatively, our findings indicate that ETEC in this region comprises a highly diverse group of bacterial enteropathogens, and that the development of prophylactic agents against ETEC faces major challenges because of this diversity.

Nosocomial outbreak of diarrhoea by enterotoxigenic Escherichia coli among preterm neonates in a tertiary care hospital in India: pitfalls in healthcare

An outbreak of watery diarrhoea accompanied by low-grade fever and weight loss in 16 preterm neonates (age range 2-20 days) admitted to a neonatal intensive care unit (NICU) over four days in August 2000 is reported. Escherichia coli having similar antibiograms were identified on routine bacterial stool cultures in 14 (87.5%) neonates and none of the other known enteropathogens were detected. An investigation was undertaken to trace the source of infection. Surveillance cultures of swabs from the utensils used to prepare milk feed, culture of the formula feed and all items handled by one particular cook yielded growth of E. coli as did culture of his hand swabs and faecal sample. The causative agent was identified as enterotoxigenic E. coli (ETEC) as toxin production could be demonstrated by reverse passive latex agglutination in all the strains of E. coli isolated both from the infected neonates and the source of infection. The outbreak was effectively controlled by appropriate therapy and institution of proper measures of hygiene after identification of the source of infection.

Prevalence of intestinal infections caused by diarrheagenic Escherichia coli in Bedouin infants and young children in Southern Israel

OBJECTIVE

To evaluate the prevalence of different Escherichia coli categories in symptomatic and asymptomatic infants and children residing in a Bedouin township in Southern Israel.

METHODS

A total of 1613 stool samples were collected from a cohort of 234 infants and young children followed from birth up to 2 years of age. E. coli colonies from stool cultures from children during a diarrhea episode and those from nondiarrhea stools were hybridized with DNA probes specific for enteropathogenic, enteroinvasive, enterotoxigenic (ETEC), enteroaggregative, diffuse adherent and enterohemorrhagic strains.

RESULTS

There were 1469 of 1613 (91%) samples positive for E. coli. The prevalence of E. coli categories was: enteroaggregative (25.9%); diffuse adherent (21.8%), ETEC (12.9%); enteropathogenic (7.3%); enterohemorrhagic (0.5%); and enteroinvasive (0.2%). ETEC, expressing the heat-stable enterotoxin (ST), was the only category isolated significantly more often from cases than from controls (P = 0.005). Of the two heat-stable enterotoxins screened in this study, only ETEC-heat stable enterotoxin (STh), the form isolated from human pathogenic ETEC, could be associated with diarrhea, whereas ETEC-STp, produced by ETEC of porcine origin, was not related to diarrhea. ETEC infections peaked during the warm, dry season. Prolonged shedding of E. coli postdiarrhea was not found in this population.

CONCLUSION

The present cohort study confirmed that in this semiurban area, highly endemic for diarrheal disease, ETEC is an important cause of diarrhea in children.