Early initiation of breastfeeding was associated with a marked reduction of the rate of diarrhea throughout the first 6 months of life, possibly because of the salutary effects of human colostrum. These data highlight the need for interventions to encourage early initiation of breastfeeding in less developed settings.

Antimicrobial susceptibility testing was performed on 3,627 isolates of Escherichia coli and 180 isolates of Shigella spp. collected in rural locations from 875 Egyptian children with diarrhoea between 1995 and 2000. The cumulative rates of resistance for E. coli and Shigella spp. were high (respectively, 68.2% and 54.8% for ampicillin, 24.2% and 23.5% for ampicillin-sulbactam, 57.2% and 42.5% for trimethoprim-sulphamethoxazole, and 50.9% and 75.4% for tetracycline). Non-enterotoxigenic E. coli (NETEC) isolates had a consistently higher level of antimicrobial resistance than did enterotoxigenic E. coli (ETEC) isolates. Trend testing showed significant decreases in resistance to ampicillin, ampicillin-sulbactam and tetracycline among all E. coli isolates. Increasing rates of resistance were observed for trimethoprim-sulphamethoxazole in ETEC isolates and Shigella spp., but not in NETEC isolates. Low levels of resistance were observed for all other antimicrobial agents tested. Overall, high levels, but decreasing trends, of resistance to commonly used antimicrobial agents were detected among isolates of E. coli and Shigella spp. from children in rural Egypt.

No abstract

No abstract

In a population-based study of diarrhea in rural, northern Egypt, 60 Shigella flexneri strains were identified, of which 10 could not be definitively serotyped. Serological analysis with commercial reagents suggested that they were serotype 1, but the strains failed to react with subserotype 1a- or 1b-specific antibodies. All 10 strains reacted with MASF 1c, a monoclonal antibody specific for a provisional S. flexneri subserotype, 1c, first identified in Bangladesh and not previously detected outside of that region. Our results show that S. flexneri subserotype 1c is not unique to Bangladesh and that the inability to detect it may reflect both the limited use of suitable screening methods and the rarity of this subserotype.

No past studies of diarrhea in children of the Middle East have examined in detail the phenotypes of enterotoxigenic Escherichia coli (ETEC) strains, which are important pathogens in this setting. During a prospective study conducted from November 1993 to September 1995 with 242 children under 3 years of age with diarrhea living near Alexandria, Egypt, 125 episodes of diarrhea were positive for ETEC. ETEC strains were available for 98 of these episodes, from which 100 ETEC strains were selected and characterized on the basis of enterotoxins, colonization factors (CFs), and O:H serotypes. Of these representative isolates, 57 produced heat-stable toxin (ST) only, 34 produced heat-labile toxin (LT) only, and 9 produced both LT and ST. Twenty-three ETEC strains expressed a CF, with the specific factors being CF antigen IV (CFA/IV; 10 of 23; 43%), CFA/II (5 of 23; 22%), CFA/I (3 of 23; 13%), PCFO166 (3 of 23; 13%), and CS7 (2 of 23; 9%). No ETEC strains appeared to express CFA/III, CS17, or PCFO159. Among the 100 ETEC strains, 47 O groups and 20 H groups were represented, with 59 O:H serotypes. The most common O serogroups were O159 (13 strains) and O43 (10 strains). O148 and O21 were each detected in five individual strains, O7 and O56 were each detected in four individual strains, O73, O20, O86, and O114 were each detected in three individual strains, and O23, O78, O91, O103, O128, and O132 were each detected in two individual strains. The most common H serogroups were H4 (16 strains), 12 of which were of serogroup O159; H2 (9 strains), all of which were O43; H18 (6 strains); H30 (6 strains); and H28 (5 strains); strains of the last three H serogroups were all O148. Cumulatively, our results suggest a high degree of clonal diversity of disease-associated ETEC strains in this region. As a low percentage of these strains expressed a CF, it remains possible that other adhesins for which we either did not assay or that are as yet undiscovered are prevalent in this region. Our findings point out some potential barriers to effective immunization against ETEC diarrhea in this population and emphasize the need to identify additional protective antigens commonly expressed by ETEC for inclusion in future vaccine candidates.

Summary Phase‐III vaccine efficacy trials typically employ individually randomized designs intended to ensure that measurements of vaccine protective efficacy reflect only direct vaccine effects. As a result, decisions about introducing newly licensed vaccines into public health programmes often fail to consider the substantially greater protection that may occur when a vaccine is deployed in public health programmes, due to the combination of direct plus indirect vaccine protective effects. Vaccine total protection can be better evaluated with cluster randomized trials. Such a design was considered to generate policy relevant data to accelerate the rationale introduction of the licensed typhoid fever Vi polysaccharide (PS) vaccine in Asia by the Diseases of the Most Impoverished (DOMI) typhoid fever programme. The DOMI's programme multi‐country study is one of the largest cluster randomized vaccine trials ever mounted in Asia, which includes approximately 200 000 individuals. Its main objective is to determine the effectiveness of a licensed Vi PS vaccine. The rationale and design of this study are discussed. Preliminary results are presented that determined the final planning of the trial before immunization. Important methodological and practical issues regarding vaccine cluster randomized designs are illustrated.