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Typical enteropathogenic Escherichia coli (tEPEC) infection is a major cause of diarrhoea and contributor to mortality in children <5 years old in developing countries. Data were analysed from the Global Enteric Multicenter Study examining children <5 years old seeking care for moderate-to-severe diarrhoea (MSD) in Kenya. Stool specimens were tested for enteric pathogens, including by multiplex polymerase chain reaction for gene targets of tEPEC. Demographic, clinical and anthropometric data were collected at enrolment and ∼60-days later; multivariable logistic regressions were constructed. Of 1778 MSD cases enrolled from 2008 to 2012, 135 (7.6%) children tested positive for tEPEC. In a case-to-case comparison among MSD cases, tEPEC was independently associated with presentation at enrolment with a loss of skin turgor (adjusted odds ratio (aOR) 2.08, 95% confidence interval (CI) 1.37–3.17), and convulsions (aOR 2.83, 95% CI 1.12–7.14). At follow-up, infants with tEPEC compared to those without were associated with being underweight (OR 2.2, 95% CI 1.3–3.6) and wasted (OR 2.5, 95% CI 1.3–4.6). Among MSD cases, tEPEC was associated with mortality (aOR 2.85, 95% CI 1.47–5.55). This study suggests that tEPEC contributes to morbidity and mortality in children. Interventions aimed at defining and reducing the burden of tEPEC and its sequelae should be urgently investigated, prioritised and implemented. [ABSTRACT FROM AUTHOR]

Given the challenges in accurately identifying unexposed controls in case-control studies of diarrhoea, we examined diarrhoea incidence, subclinical enteric infections and growth stunting within a reference population in the Global Enteric Multicenter Study, Kenya site. Within 'control' children (0-59 months old without diarrhoea in the 7 days before enrolment, n = 2384), we examined surveys at enrolment and 60-day follow-up, stool at enrolment and a 14-day post-enrolment memory aid for diarrhoea incidence. At enrolment, 19% of controls had ⩾1 enteric pathogen associated with moderate-to-severe diarrhoea ('MSD pathogens') in stool; following enrolment, many reported diarrhoea (27% in 7 days, 39% in 14 days). Controls with and without reported diarrhoea had similar carriage of MSD pathogens at enrolment; however, controls reporting diarrhoea were more likely to report visiting a health facility for diarrhoea (27% vs. 7%) or fever (23% vs. 16%) at follow-up than controls without diarrhoea. Odds of stunting differed by both MSD and 'any' (including non-MSD pathogens) enteric pathogen carriage, but not diarrhoea, suggesting control classification may warrant modification when assessing long-term outcomes. High diarrhoea incidence following enrolment and prevalent carriage of enteric pathogens have implications for sequelae associated with subclinical enteric infections and for design and interpretation of case-control studies examining diarrhoea. [ABSTRACT FROM AUTHOR]

Abstract: Aims: O‐polysaccharide (OPS) molecules are protective antigens for several bacterial pathogens, and have broad utility as components of glycoconjugate vaccines. Variability in the OPS chain length is one obstacle towards further development of these vaccines. Introduction of sizing steps during purification of OPS molecules of suboptimal or of mixed lengths introduces additional costs and complexity while decreasing the final yield. The overall goal of this study was to demonstrate the utility of engineering Gram‐negative bacteria to produce homogenous O‐polysaccharide populations that can be used as the basis of carbohydrate vaccines by overexpressing O‐polysaccharide chain length regulators of the Wzx‐/Wzy‐dependent pathway. Method and Results: The O‐polysaccharide chain length regulators wzzB and fepE from Salmonella Typhimurium I77 and wzz2 from Pseudomonas aeruginosa PAO1 were cloned and expressed in the homologous organism or in other Gram‐negative bacteria. Overexpression of these Wzz proteins in the homologous organism significantly increased the proportion of long or very long chain O‐polysaccharides. The same observation was made when wzzB was overexpressed in Salmonella Paratyphi A and Shigella flexneri, and wzz2 was overexpressed in two other strains of P. aeruginosa. Conclusions: Overexpression of Wzz proteins in Gram‐negative bacteria using the Wzx/Wzy‐dependant pathway for lipopolysaccharide synthesis provides a genetic method to increase the production of an O‐polysaccharide population of a defined size. Significance and Impact of the Study: The methods presented herein represent a cost‐effective and improved strategy for isolating preferred OPS vaccine haptens, and could facilitate the further use of O‐polysaccharides in glycoconjugate vaccine development. [ABSTRACT FROM AUTHOR]

Enterotoxigenic Escherichia coli (ETEC) use colonization factors to attach to the human intestinal mucosa, followed by enterotoxin expression that induces net secretion and diarrhoeal illness. ETEC strain H10407 expresses CFA/I fimbriae, which are composed of multiple CfaB structural subunits and a CfaE tip subunit. Currently, the contribution of these individual fimbrial subunits in intestinal binding remains incompletely defined. To identify the role of CfaE in attachment in the native ETEC background, an R181A single-amino-acid substitution was introduced by recombination into the H10407 genome. The substitution of R181A eliminated haemagglutination and binding of intestinal mucosa biopsies in in vitro organ culture assays, without loss of CFA/I fimbriae expression. Wild-type in trans plasmid-expressed cfaE restored the binding phenotype . In contrast, in trans expression of cfaE containing amino acid 181 substitutions with similar amino acids, lysine, methionine and glutamine did not restore the binding phenotype, indicating that the loss of the binding phenotype was due to localized areas of epitope disruption. R181 appears to have an irreplaceable role in the formation of a receptor-binding feature on CFA/I fimbriae. The results specifically indicate that the CfaE tip protein is a required binding factor in CFA/I-mediated ETEC colonization, making it a potentially important vaccine antigen. [ABSTRACT FROM AUTHOR]

Nonenterotoxigenic strains no. 1196-78 and no. 1074-78 of Vibrio cholerae serogroup 01 (biotype El Tor, serotype Ogawa) were isolated from sewage water in Brazil and fed to 20 volunteers. Neither strain caused diarrhea. None of the seven volunteers who ingested Ogawa strain no. 1074-78(106 organisms) excreted the organism whereas eight of the 13 volunteers who ingested Ogawa strain no. 1196-78 (106 or 108 organisms) did excrete the organism in their stools. None of 114 stool-culture isolates yielded cholera enterotoxin, and none of the 20 volunteers had significant increases in serum titers of antitoxin as measured by enzyme-linked immunosorbent assay although six of the volunteers had slightly elevated vibriocidal antibody levels. Six volunteers used as controls and four volunteers who had stool cultures positive for strain no. 1196-78 of V. cholerae were challenged with pathogenic EI Tor Ogawa strain no. E7946 (106 organisms) to determine if previous ingestion of the Brazilian strain would induce protective immunity. All 10 of the volunteers developed diarrhea, and the severity of the illness was similar in both groups. [ABSTRACT FROM PUBLISHER]

The discovery of 11 persons infected with Vibrio cholerae serogroup O1 (biotype EI Tor, serotype Inaba) in southwestern Louisiana in 1978 provided an opportunity to evaluate the serologic response to this agent in North Americans with naturally acquired infection. One antibacterial assay (vibriocidal assay) and two antitoxin assays (enzymelinked immunosorbent assays [ELISA] and rabbit skin permeability factor assay) were used. Antitoxin levels were elevated longer than vibriocidal antibody levels, and asymptomatic infected persons had levels of antitoxin and vibriocidal antibody as high as those of persons with clinical cholera. With use of serologic criteria derived from these studies, one additional person infected with V. cholerae O1 was discovered, and a relatively low (4%–7%) prevalence rate of elevated levels of vibriocidal antibody and antitoxin was found in a serum survey of a community with several known cases. Comparison of the results from the ELISA and the rabbit skin permeability factor assay demonstrated similar rates of elevated levels of antitoxin, but the ELISA required less time and less serum per sample analyzed. [ABSTRACT FROM PUBLISHER]

A series of O:H serotypes of E. coli were incriminated by epidemiologic studies in the period 1945-1960 as a cause of epidemic diarrhea in infant nurseries as well as a major cause of sporadic infant diarrhea in the community. The term enteropathogenic E. coli was coined to refer to these infant diarrhea-associated serotypes. In the early 1970s, with the advent of laboratory tests to assess heat-labile and heat-stable enterotoxin production and enteroinvasiveness of E. coli, the classic serotype enteropathogenic E. coli strains were found to lack those particular properties. These observations led some to question their pathogenicity. However, since 1978, enteropathogenic E. coli have come to be appreciated anew as a separate class of diarrheagenic E. coli that cause diarrhea by distinct pathogenic mechanisms. The pathogenesis of these strains, which have been shown to cause diarrhea in volunteers, appears to involve both an enteroadhesiveness step and production of a toxin identical to Shigella toxin. A 55- to 65-Mdalton plasmid is involved in the attachment of enteropathogenic E. coli to intestinal mucosa which results in a pathognomonic histopathologic lesion visualized by electron microscopy. The lesion involves dissolution of enterocyte microvilli by the bacteria, effacement of the enterocyte outer membrane, and formation of a pedestal around the bacterium at point of contact with the outer membrane of the enterocyte. Case-control epidemiologic studies carried out since 1975 document that enteropathogenic E. coli remain an important cause of sporadic infant diarrhea in the community with up to 30 per cent of cases of acute diarrhea in young infants in Brazil and South Africa being attributed to these pathogens. Although nursery epidemics of enteropathogenic E. coli diarrhea have virtually disappeared from industrialized countries, some sporadic enteropathogenic E. coli diarrhea in infants in the community continues to occur. The relative importance of enteropathogenic E. coli as a cause of sporadic diarrhea in both industrialized and developing countries needs to be reassessed. New diagnostic techniques are awaited to simplify this task. [ABSTRACT FROM AUTHOR]

Experiments were performed in Baltimore. Maryland and in Santiago, Chile, to determine the level of Salmonella typhi antigen-driven in vitro lymphocyte replication response which signifies specific acquired immunity to this bacterium and to determine the best method of data analysis and form of data presentation. Lymphocyte replication was measured as incorporation of 3H-thymidine into desoxyribonucleic acid. Data (ct/min/culture) were analyzed in raw form and following log transformation, by non-parametric and parametric statistical procedures. A preference was developed for log-transformed data and discriminant analysis. Discriminant analysis of log- transformed data revealed 3H-thymidine incorporation rates > 3 433 for particulate S. typhi. Ty2 antigen stimulated cultures signified acquired immunity at a sensitivity and specificity of 82.7; for soluble S. typhi O polysaccharide antigen-stimulated cultures, ct/mm/culture values of > 1 237 signified immunity (sensitivity and specificity 70.5%). [ABSTRACT FROM AUTHOR]

Thirteen patients with Haemophilus influenzae type b pneumonia are reported to emphasise the clinical, radiographic, and therapeutic aspects of this illness. All but one patient was under 2 1/2 years of age. The presenting complaint was a variable duration of upper respiratory infection and fever in most cases. One-third of patients had radiographic evidence of pleural involvement; one-third showed a patchy bronchopneumonia on roentgenogram; and the remainder had segmental or lobar infiltrates. Clinical response to antibiotic therapy was prompt in patients without pleural involvement. [ABSTRACT FROM AUTHOR]

To determine the association of tissue culture-adherent EscIherichia coli with diarrhea, serotyped E. coli strains isolated in a yearlong case-control study of infantile diarrhea in Bangkok, Thailand, were examined for adherence to HeLa cells and for hybridization with the enteropathogenic E. coli adherence factor, the F1845, and the enteroaggregative E. coli (EAggEC) DNA probes. E. coli that adhered to HeLa cells in a localized adherence (LA) pattern (LA E. coli) was isolated from 26 of 509 infants with diarrhea (cases) and 9 of 509 age-matched controls (P = .006); E. coli with diffuse or aggregative adherence (DA or AA) to HeLa cells or that hybridized with the FI845 or EAggEC probes was not associated with infantile diarrhea. LA E. coli of classical enteropathogenic E. coli (EPEC) serotypes was isolated from II cases and I control (P = .003). EPEC O44:H18 that adhered to HeLa cells in a DA pattern and hybridized with the FI845 DNA probe was the predominant E. coli (five of five colonies tested) isolated from a 5-month-old girl with diarrhea in whom no other enteric infections were identified. Although LA E. coli was highly associated with infantile diarrhea, the role of DA and AA E. coli was uncertain in this setting. [ABSTRACT FROM PUBLISHER]

In Chile, a country with an exceedingly high incidence of typhoid, untreated sewage is applied directly to fields where salad vegetables are cultivated. Water used for irrigation was examined for the presence of Salmonella typhi, by making use of the sewer-swab technique. S typhi was isolated in 8 (11%) of 76 irrigation samples examined from nonindustrial, polluted water. This supports the hypothesis that crops grown with water contaminated with feces are important vehicles in the transmission of S typhi in this endemic area. Since sewage treatment plants will not be available in Santiago in the near future, emphasis is being placed on devising alternative methods of irrigation and on growing vegetables that are cooked before being eaten. [ABSTRACT FROM PUBLISHER]