Diarrhea in developed and developing countries: magnitude, special settings, and etiologies

Diarrhoea in elderly people: aetiology, and clinical characteristics

We examined the characteristics of elderly people attending the Dhaka Hospital of ICDDR,B. The hospital has a diarrhoeal disease surveillance system that enrols a 2% systematic sample of all patients visiting the hospital. We reviewed data of all patients enrolled into the surveillance system (n = 13,782) over the period 1996-2001 to identify patients aged 60 y and above for inclusion into the current study (4% of all surveillance patients; n = 478). V. cholerae O1 was the most common enteric pathogen isolated from faecal culture of the patients (20%), followed by ETEC (13%), Shigella (11%), V. cholerae O139 (10%), Campylobacter jejuni (5%), Salmonella (3%), EPEC (2%), rotavirus (4%), and E. histolytica (2%). The isolation rate of V. cholerae O139 and Shigella was higher among the elderly compared to adults (15-59 y of age, 10% vs 6%, and 11% vs 7% respectively; p < 0.05 for both comparisons). Compared to 15-59-y-olds, a significantly higher proportion of the elderly had visible blood in stools (8% vs 5%), required short-stay ward admission (86% vs 82%) or referral (1% vs < 1%) to a health facility. Early initiation of oral or i.v. rehydration therapy, prompt referral, and immediate clinical diagnosis for assessment of the need for antibiotic therapy might be beneficial for the elderly.

Determinants of impaired growth among hospitalized children: a case-control study

CONTEXT

Protein energy malnutrition constitutes a public health problem, especially in less affluent countries. The identification of amenable predictive risk factors is of major importance for policy makers to plan interventions to reduce infant malnutrition.

OBJECTIVE

To identify risk factors for protein energy malnutrition among hospitalized low-income children aged 6 to 24 months.

TYPE OF STUDY

Case-control study.

SETTING

Two public hospitals in Recife, Brazil.

PARTICIPANTS

The cases were 124 infants with length-for-age below the 10th percentile of the National Center for Health Statistics curve and the controls were 241 infants with length-for-age equal to or above the 10th percentile who were recruited in the same infirmary.

METHODS

Cases and controls were compared in relation to a variety of sociodemographic, environmental and reproductive factors, and their healthcare, previous feeding practice and morbidity. Logistic regression analysis was used to investigate the net effect of risk factors on infant malnutrition, after adjusting for potential confounding variables.

RESULTS

The mother's age, possession of a TV set, type of water supply, family size and location of the home were significantly associated with child malnutrition in the bivariate analysis. However, these associations lost their significance after adjusting for other explanatory variables in the hierarchical logistic regression analysis. This analysis showed that low birth weight contributed the largest risk for impaired growth. Increased risks of infant malnutrition were also significantly associated with households that had no toilet facilities or refrigerator, high parity for the mother, no breastfeeding of the infant, inadequate vaccination coverage and previous hospitalization for diarrhea and pneumonia.

DISCUSSION

The literature shows that chronic malnutrition, as assessed by low length-for-age indexes, is often related to low income. However, this was not the case in this study, in which other variables had greater impact on child growth.

CONCLUSIONS

In view of the multiple causes of malnutrition, the interrelationship among its determinants should be taken into account when adopting strategies for its reduction and prevention.

Simultaneous detection of Entamoeba histolytica, Giardia lamblia, and Cryptosporidium parvum in fecal samples by using multiplex real-time PCR

Entamoeba histolytica, Giardia lamblia, and Cryptosporidium are three of the most important diarrhea-causing parasitic protozoa. For many years, microscopic examination of stool samples has been considered to be the "gold standard" for diagnosis of E. histolytica, G. lamblia, and C. parvum infections. Recently, more specific and sensitive alternative methods (PCR, enzyme-linked immunosorbent assay, and direct fluorescent-antibody assay) have been introduced for all three of these parasitic infections. However, the incorporation in a routine diagnostic laboratory of these parasite-specific methods for diagnosis of each of the respective infections is time-consuming and increases the costs of a stool examination. Therefore, a multiplex real-time PCR assay was developed for the simultaneous detection of E. histolytica, G. lamblia, and C. parvum in stool samples. The multiplex PCR also included an internal control to determine efficiency of the PCR and detect inhibition in the sample. The assay was performed on species-specific DNA controls and a range of well-defined stool samples, and it achieved 100 percent specificity and sensitivity. The use of this assay in a diagnostic laboratory would provide sensitive and specific diagnosis of the main parasitic diarrheal infections and could improve patient management and infection control.

Microbiological characterization and probiotic potential of koko and koko sour water, African spontaneously fermented millet porridge and drink

AIMS

To identify and examine the diversity of predominant lactic acid bacteria (LAB) in koko and koko sour water (KSW) from different Ghanaian production sites with regard to pattern of fermentation (API 50 CHL), genotype, antimicrobial activity, and resistance to low pH and bile salts.

METHODS AND RESULTS

In total 215 LAB were isolated from koko and KSW. The isolates were identified using intergenic transcribed spacers (ITS)-PCR restriction fragment length polymorphism (RFLP), API 50 CHL, restriction enzyme analysis with pulsed-field gel electrophoresis (REA-PFGE) and sequencing of the 16S rRNA gene. The dominating micro-organisms in koko was found to be Weisella confusa and Lactobacillus fermentum, followed by Lact. salivarius and Pediococcus spp. Chemometric data analysis were used to link the LAB species to the different production stages and production sites. At intra-species level the isolates were found to have a great diversity. The isolates were investigated for antimicrobial activity using agar diffusion assays, and acid and bile tolerance. Most isolates showed low levels of antimicrobial activity towards the indicator strain Listeria innocua, but not towards the bacteriocin-sensitive Lact. sakei. Growth of all LAB isolates was unaffected by the presence of 0.3% (v/v) oxgall bile. The isolates were able to survive, but were not able to grow in growth medium adjusted to pH 2.5.

CONCLUSIONS

The dominating LAB of koko and KSW were W. confusa and Lact. fermentum showing a pronounced taxonomic biodiversity at sub-species level between stages within the production as well as between production sites. Other species observed in KSW were Lact. salivarius, Ped. pentosaceus, Ped. acidilactici and Lact. paraplantarum. They occurred in levels of 108 CFU ml-1 in fresh KSW and showed uniform antimicrobial activity, and acid and bile tolerance.

SIGNIFICANCE AND IMPACT OF THE STUDY

The present study gives a detailed picture of the taxonomy and diversity of LAB in an African-fermented millet product that may have potential as a probiotic product for the local population. The chemometric tools Principal Component Analysis and anova Partial Least Squares Regression were proven to be useful in the analysis of microbial groupings and associations with specific sites and stages in the production of koko and KSW.

Etiology of acute diarrhea in adults in southwestern Nigeria

Stool specimens from 113 adult outpatients with diarrhea in southwestern Nigeria and 63 controls were examined for bacterial and parasitic enteric pathogens. Enterohemorrhagic Escherichia coli (EHEC) (P < 0.02), enteroaggregative E. coli (EAEC) (P < 0.02), and Entamoeba histolytica (P < 0.0002) were significantly associated with diarrhea. Salmonella, Shigella, nontoxigenic Vibrio cholerae, other categories of diarrheagenic E. coli, as well as a variety of helminths were recovered more frequently from the stools of patients than from the stools of controls but did not show a significant association with disease. Multiple pathogens were recovered from 36.3% of specimens, and bloody diarrhea was commonly associated with E. histolytica and diarrheagenic E. coli infections. The majority of EHEC isolates were non-O157 strains that carried the stx(2) gene. Of the 23 EHEC-infected patients, 12 (52.2%) presented during the 10th week of the study. EHEC strains isolated within this cluster were more likely to hybridize with the enterohemolysin gene probe, to be nonmotile and sorbitol positive, and to fail to agglutinate O157 antisera. Pulsed-field gel electrophoresis demonstrated that the only strains with XbaI profiles that occurred more than once were isolated during the 10th and 11th weeks of the study, suggesting an outbreak. The study has demonstrated that E. histolytica, EHEC, and EAEC are important diarrheal pathogens within the study area and that sporadic and epidemic EHEC infections occur in developing as well as developed countries. Routine surveillance for diarrheagenic E. coli, even only at the tertiary-care level, would be useful in identifying outbreaks and assist in identifying environmental reservoirs and transmission routes.

Probiotics for treating infectious diarrhoea

BACKGROUND

Probiotics are microbial cell preparations or components of microbial cells that have a beneficial effect on the health and well being of the host. Probiotics may offer a safe intervention in acute infectious diarrhoea to reduce the duration and severity of the illness.

OBJECTIVES

To assess the effects of probiotics in proven or presumed infectious diarrhoea.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group's trials register (December 2002), the Cochrane Controlled Trials Register (The Cochrane Library Issue 4, 2002), MEDLINE (1966 to 2002), EMBASE (1988 to 2002), and reference lists from studies and reviews. We also contacted organizations and individuals working in the field, and pharmaceutical companies manufacturing probiotic agents.

SELECTION CRITERIA

Randomized controlled trials comparing a specified probiotic agent with placebo or no probiotic in people with acute diarrhoea that is proven or presumed to be caused by an infectious agent.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial methodological quality and extracted data.

MAIN RESULTS

Twenty-three studies met the inclusion criteria with a total of 1917 participants, mainly in countries with low overall mortality rates. Trials varied in relation to the probiotic(s) tested, dosage, methodological quality, and the diarrhoea definitions and outcomes. Probiotics reduced the risk of diarrhoea at 3 days (relative risk 0.66, 95% confidence interval 0.55 to 0.77, random effects model; 15 studies) and the mean duration of diarrhoea by 30.48 hours (95% confidence interval 18.51 to 42.46 hours, random effects model, 12 studies). Subgroup analysis by probiotic(s) tested, rotavirus diarrhoea, national mortality rates, and age of participants did not fully account for the heterogeneity.

REVIEWERS' CONCLUSIONS

Probiotics appear to be a useful adjunct to rehydration therapy in treating acute, infectious diarrhoea in adults and children. More research is needed to inform the use of particular probiotic regimens in specific patient groups.

A 5-year study of the bacterial pathogens associated with acute diarrhoea on the island of Crete, Greece, and their resistance to antibiotics

During a 5-year period (1995-1999) a total of 7090 stool samples obtained from patients with acute diarrhoea, mostly community-acquired, were examined for bacterial pathogens, in the Greek island of Crete. One or more enteric pathogens were isolated from 987 patients (14%). Salmonella enterica were the most commonly isolated bacteria (6%), followed by Campylobacter spp. (4.2%), and enteropathogenic Escherichia coli (EPEC) (1.8%). Yersinia enterocolitica (0.6%), Shigella spp. (0.3%), and Aeromonas hydrophila (0.04%), were less frequently isolated. Clostridium difficile was isolated from 65 out of 451 diarrhoeal specimens examined (14.4%). Toxin B was detected in all cases. No verotoxigenic E. coli strains were identified. Resistance to ampicillin was observed in 31.5% of the Salmonella, 58.3% of the Shigella and 31.5% of the EPEC isolates. Resistance to trimethoprim-sulfamethoxazole was observed in 4.4% of the Salmonella, 30.5% of the Shigella, and 18.5% of the EPEC isolates. High percentages of resistance to quinolones (44.5% to norfloxacin, and 40.5% to ciprofloxacin), were found among Campylobacter isolates, while resistance to erythromycin was observed in 14.9% of them. With the present study we continue the surveillance of bacterial pathogens associated with diarrhoeal disease on the island of Crete.

Viruses causing gastroenteritis

Acute gastroenteritis is one of the most common diseases in humans worldwide. Viruses are recognized as important causes of this disease, particularly in children. Since the Norwalk virus was identified as a cause of gastroenteritis, the number of viral agents associated with diarrheal disease in humans has steadily increased. Rotavirus is the most common cause of severe diarrhea in children under 5 years of age. Astrovirus, calicivirus and enteric adenovirus are also important etiologic agents of acute gastroenteritis. Other viruses, such as toroviruses, coronaviruses, picobirnaviruses and pestiviruses, are increasingly being identified as causative agents of diarrhea. In recent years, the availability of diagnostic tests, mainly immunoassays or molecular biology techniques, has increased our understanding of this group of viruses. The future development of a safe and highly effective vaccine against rotavirus could prevent, at least, cases of severe diarrhea and reduce mortality from this disease.

Efficacy of probiotic use in acute diarrhea in children: a meta-analysis

Our objective was to determine the efficacy of probiotic use in reducing the duration of increased stool output in children with acute diarrheal illness. Eligible studies were limited to trials of probiotic therapy in otherwise healthy children <5 years old with acute-onset diarrhea. The main outcome variable was difference in diarrhea duration between treatment and control groups. Our meta-analysis of 18 eligible studies suggests that coadministration of probiotics with standard rehydration therapy reduces the duration of acute diarrhea by approximately 1 day [random-effects pooled estimate = -0.8 days (-1.1, -0.6), P < 0.001]. Differences in treatment effect between studies was assessed by calculating the Q statistic (Q = 204. 1, P < 0.001). In subsequent analyses limited to studies of hospitalized children, to double-blinded trials, and to studies evaluating lactobacilli, the pooled estimates were similar (-0.6 to -1.2 days, P < 0.001). In conclusion, bacterial probiotic therapy shortens the duration of acute diarrheal illness in children by approximately one day.

Upregulation of CFTR expression but not SLC26A3 and SLC9A3 in ulcerative colitis

In inflamed colonic mucosa, the equilibrium between absorptive and secretory functions for electrolyte and salt transport is disturbed. We compared the expression of three major mediators of the intestinal salt transport between healthy and inflamed colonic mucosa to understand the pathophysiology of diarrhea in inflammatory bowel disease. Expression levels of the cystic fibrosis transmembrane regulator (CFTR) (Cl- channel), SLC26A3 (Cl-/HCO exchanger) and SLC9A3 (Na+/H+ exchanger) mRNAs were measured by real-time quantitative RT-PCR in peroperative colonic samples from controls (n = 4) and patients with ulcerative colitis (n = 10). Several samples were obtained from each individual. Tissue samples were divided into three subgroups according to their histological degree of inflammation. Expression of CFTR and SLC26A3 proteins were determined by immunohistochemistry and Western blotting from the same samples, respectively. Increased expression of CFTR mRNA was observed in all three groups of affected tissue samples, most pronounced in mildly inflamed colonic mucosa (5-fold increase in expression; P < 0.001). The expression of the CFTR protein was detected from health and inflamed colon tissue. Although the expression of the SLC26A3 mRNA was significantly decreased in severe ulcerative colitis (P < 0.05), the SLC26A3 protein levels remained unchanged in all groups. The expression of SLC9A3 mRNA was significantly changed between the mild and severe groups. Intestinal inflammation modulates the expression of three major mediators of intestinal salt transport and may contribute to diarrhea in ulcerative colitis both by increasing transepithelial Cl- secretion and by inhibiting the epithelial NaCl absorption.

Phloxine B interacts with the cystic fibrosis transmembrane conductance regulator at multiple sites to modulate channel activity

The fluorescein derivative phloxine B is a potent modulator of the cystic fibrosis transmembrane conductance regulator (CFTR). Low micromolar concentrations of phloxine B stimulate CFTR Cl(-) currents, whereas higher concentrations of the drug inhibit CFTR. In this study, we investigated the mechanism of action of phloxine B. Phloxine B (1 microm) stimulated wild-type CFTR and the most common cystic fibrosis mutation, DeltaF508, by increasing the open probability of phosphorylated CFTR Cl(-) channels. At each concentration of ATP tested, the drug slowed the rate of channel closure without altering the opening rate. Based on the effects of fluorescein derivatives on transport ATPases, these data suggest that phloxine B might stimulate CFTR by binding to the ATP-binding site of the second nucleotide-binding domain (NBD2) to slow the dissociation of ATP from NBD1. Channel block by phloxine B (40 microm) was voltage-dependent, enhanced when external Cl(-) concentration was reduced and unaffected by ATP (5 mm), suggesting that phloxine B inhibits CFTR by occluding the pore. We conclude that phloxine B interacts directly with CFTR at multiple sites to modulate channel activity. It or related agents might be of value in the development of new treatments for diseases caused by the malfunction of CFTR.

Incidence and prevalence of human group C rotavirus infections in Argentina

The incidence of human group C rotavirus infections among children and adults in Buenos Aires was evaluated by enzyme linked immunosorbent assays (ELISA) based on recombinant group C VP6 protein (Cowden strain). A total of 976 stool samples taken from patients (ages 6 months to 15 years) with acute diarrhea were tested for the presence of group C rotavirus. Among these, only 10 (1.02%) were group C rotavirus positive by enzyme-linked immunosorbent assay (ELISA) confirmed by absorption with group C VP6 antibodies and by RT-PCR for both VP6 and VP7 genes. The average age (5.86 years) was significantly superior to that in group A-infected patients (1.63 years). Previous exposure to this virus was assessed by detecting specific IgG in sera taken from healthy individuals grouped by age. Of 844 sera tested, 425 (50.3%) were group C IgG positive by ELISA, confirmed by Western blot analysis. The rates of IgG positivity for group A and C rotaviruses during the first years of life indicated that infections with group C are frequent in older children (3-5 years), whereas group A infections are prevalent in infants and young children (6-18 months). This study shows that group C rotavirus infections in Argentine children occur later in life than group A and are relatively common in spite of the low detection rate of this virus.

Stool cultures for nosocomial diarrhea: money down the drain?

The authors report on a modified “3-day rule” for limiting low-yield stool cultures obtained from hospitalized patients with nosocomial diarrhea. The modified rule addresses the two known weaknesses of the strict 3-day rule: immune-suppressed patients and nosocomial outbreaks of bacterial gastroenteritis. In addition, the modified rule addresses a third group of previously unidentified patients at risk of non-Clostridium difficile bacterial nosocomial diarrhea: patients older than 65 with comorbidity. The modified rule would decrease the number of stool cultures by half without missing any clinically significant cases. The authors recommend the modified 3-day rule as a way to “greatly reduce the laboratory burden of stool culture, yet provide rapid diagnosis for patients at increased risk of nosocomial bacterial gastroenteritis.”

Prevention of bacterial diarrhea by pasteurization of drinking water in Kenya

Diarrheal disease is one of the major causes of morbidity and mortality in developing countries. Drinking water is a primary transmission route of infectious diarrheagenic bacteria in a rural area of Kenya (Microbiol. Immunol. 41: 773-778, 1997). We tried to prevent diarrhea at villages with approximately 1,500 households in Kenya by pasteurizing drinking water. A durable simple thermoindicator which changes color at 70 C was used as an indicator of pasteurization. The number of households in which drinking water was coliform bacteria-free increased from 10.7% to 43.1% after adoption of a pasteurization practice. Consequently, the incidence of severe diarrhea among people drinking pasteurized water was significantly lower than in people taking raw water (odds ratio=0.55, P=0.0016). The reduction ratio of the incidence after pasteurization was nearly equivalent with that after the adoption of a boiling method. Employment of women leaders as fieldworkers and demonstration of bacterial colony disappearance on agar plates by pasteurization also affected reduction of the diarrheal incidence.

Sensor, a population-based cohort study on gastroenteritis in the Netherlands: incidence and etiology

A prospective population-based cohort study with a nested case-control study was conducted to estimate the incidence of gastroenteritis and the associated pathogens in the general Dutch population. Follow-up of two consecutive cohorts was performed by weekly reporting cards from December 1998 to December 1999. Cases and controls in the case-control study supplied a questionnaire and stool samples. The standardized gastroenteritis incidence was 283 per 1,000 person-years. The incidence rose with increasing level of education and was higher for persons with a history of diarrhea and for young children. Bacterial pathogens accounted for 5% of cases, bacterial toxins for 9%, parasites for 6%, and viral pathogens for 21%, with Norwalk-like virus (NLV) as the leading pathogen in 11% of cases. The gastroenteritis incidence was higher than that reported for England, but lower than for the United States. In community cases, viral pathogens are the leading cause of gastroenteritis, with NLV being the number one cause of illness in all age groups but one. In many countries, preventive measures are implemented to decrease bacterial infections. However, additional prevention of viral infections, especially NLV, might significantly decrease the number of gastroenteritis cases in the community.

Clostridium difficile

Clostridium difficile is a major cause of antibiotic-associated diarrhea and colitis. The incidence of infection with this organism is increasing in hospitals worldwide, consequent to the widespread use of broad-spectrum antibiotics. Pathogenic strains of C. difficile produce two protein exotoxins, toxin A and toxin B, that cause colonic mucosal injury and inflammation. Many patients who are colonized are asymptomatic, and recent evidence indicates that diarrhea and colitis occur in those individuals who lack a protective antitoxin immune response. In patients who do develop symptoms, the spectrum of C. difficile disease ranges from mild diarrhea to fulminant pseudomembranous colitis. Prevention of nosocomial C. difficile infection involves judicious use of antibiotics and multidisciplinary infection control measures to reduce environmental contamination and patient cross-infection. Ultimately, active or passive immunization against C. difficile may be an effective means of controlling the growing problem of nosocomial C. difficile diarrhea and colitis.

Infectious diarrhea in children

Infectious diarrhea in children remains an important cause of morbidity in North America with rotavirus, nontyphoidal salmonella, Campylobacter and Giardia being the predominant pathogens in children younger than 5 years. Knowledge of the epidemiology of the diarrheal illness in a community together with the clinical information are necessary when determining the extent of investigation. Oral rehydration remains the mainstay of therapy and antibiotics are reserved for specific clinical situations and infections.

Acute diarrhoea in children treated in an outpatient setting in Athens, Greece

OBJECTIVE

To describe the epidemiology and aetiology of acute diarrhoea among children treated exclusively in an outpatient setting in Greece.

METHODS

During 1999, children with acute diarrhoea who attended the emergency department of our hospital were prospectively studied. Patients requiring hospitalization were excluded. Stool specimens were tested microscopically, for bacterial enteropathogens by standard and selective medium cultures and for rotavirus and adenovirus by latex agglutination test.

RESULTS

One hundred and thirty-two children (median age: 2 years) were included in the study; an enteropathogen was detected in 63 (48%) of them. Isolates included rotavirus (19 patients), Salmonella sp (12), Campylobacter sp (10), Aeromonas sp (9), enteropathogenic Escherichia coli (6), adenovirus (6), Giardia lamblia (4), Yersinia enterocolitica (2) and Shigella sp (1). Half of the bacterial cases occurred from August to October, and two rotavirus-associated peaks occurred during February and August. Acute diarrhoea caused by viruses affected exclusively children under six years of age, mainly those attending day care centres. Macroscopic blood in stools was reported only among patients with a bacterial infection. Socioeconomic characteristics were not helpful in differentiating disease due to specific enteropathogens.

CONCLUSIONS

Bacterial enteropathogens account for a significant proportion of acute diarrhoea in children treated in the outpatient setting in Greece. Rotavirus is also a frequent cause affecting mostly younger children and those attending day care centers. The presence of blood in stools and the seasonality of bacterial infections may enable their presumptive diagnosis.

Etiology of gastroenteritis in sentinel general practices in the netherlands

Data from a general practice-based, case-control study on gastroenteritis and the pathogens related to this disease were used to study the association between specific pathogens and the infected patients' ages and symptoms. For comparison, the occurrence of these pathogens in control patients, stratified by age, also is presented. In children with gastroenteritis who were <5 years of age, rotavirus (in 21% of patients) and Norwalk-like virus (NLV; in 15%) were the most common pathogens. Among patients who were 5-14 years of age, Campylobacter species (in 16% of patients) and Giardia lamblia (in 10%) were the most common pathogens. In the older patients, Campylobacter species was also the most common pathogen (8% to 15% of patients). In addition, several symptoms in case patients were associated with specific pathogens. Blood in the stool was associated with infection with Campylobacter species. In patients with fever, Salmonella species, Campylobacter species, and rotavirus were detected relatively often. Vomiting was associated with NLV and rotavirus. This is the first study in The Netherlands and one of the first studies in the world that has investigated a broad range of pathogens recovered from an unselected population of patients who had consulted general practitioners because of gastroenteritis.

Inhibition of enteroaggregative Escherichia coli adhesion to HEp-2 cells by secretory immunoglobulin A from human colostrum

BACKGROUND

Enteroaggregative Escherichia coli (EAEC) is an important agent of the persistent diarrhea among low socioeconomic level children in developing countries that may be associated with chronic undernourishment. Breast-feeding is effective in protecting infants against diarrhea and other infectious diseases. The aim of the study is to verify the ability of human colostrum to inhibit aggregative adhesion of EAEC to HEp-2 cells and the presence of antibodies reactive to antigenic fractions of EAEC in colostrum samples.

METHODS

Enzyme-linked immunosorbent assay, immunoblotting and adhesion assays of EAEC to HEp-2 cells were done with pooled or individual colostrum samples (n = 35). Assays were performed with a well-known EAEC strain, 044:H18 E. coli (strain 042). Colostral IgA was isolated by affinity chromatography in Sepharose anti-human alpha chain column.

RESULTS

Total colostrum and isolated IgA inhibited EAEC adhesion, and this ability was associated with the presence of IgA antibodies against a 15-kDa band, compatible with the subunits of aggregative adherence fimbrial adhesin II, characteristic of the 042 strain, absent in its plasmid-cured isogenic strain, that was used as control. Individual colostrum samples also inhibited adhesion, showed variable antibody titles against EAEC antigens in enzyme-linked immunosorbent assay and recognized many antigenic fractions in immunoblotting assays, including the 15-kDa band.

CONCLUSIONS

These results confirm that IgA from human colostrum inhibits adhesion of EAEC to HEp-2 cells and suggest that colostrum IgA antibodies reactive to EAEC antigens may play a role in protection of infants against diarrhea caused by these bacteria.

Membrane interactions of a novel viral enterotoxin: rotavirus nonstructural glycoprotein NSP4

The rotavirus enterotoxin, NSP4, is a novel secretory agonist that also plays a role in the unique rotavirus morphogenesis that involves a transient budding of newly made immature viral particles into the endoplasmic reticulum. NSP4 and an active peptide corresponding to NSP4 residues 114 to 135 (NSP4(114-135)) mobilize intracellular calcium and induce secretory chloride currents when added exogenously to intestinal cells or mucosa. Membrane-NSP4 interactions may contribute to these alterations; however, details of a lipid-binding domain are unresolved. Therefore, circular dichroism was used to determine (i) the interaction(s) of NSP4 and NSP4(114-135) with model membranes, (ii) the conformational changes elicited in NSP4 upon interacting with membranes, (iii) if NSP4(114-135) is a membrane interacting domain, and (iv) the molar dissociation constant (K(d)) of NSP4(114-135) with defined lipid vesicles. Circular dichroism revealed for the first time that NSP4 and NSP4(114-135) undergo secondary structural changes upon interaction with membrane vesicles. This interaction was highly dependent on both the membrane surface curvature and the lipid composition. NSP4 and NSP4(114-135) preferentially interacted with highly curved, small unilamellar vesicle membranes (SUV), but significantly less with low-curvature, large unilamellar vesicle membranes (LUV). Binding to SUV, but not LUV, was greatly enhanced by negatively charged phospholipids. Increasing the SUV cholesterol content, concomitant with the presence of negatively charged phospholipids, further potentiated the interaction of NSP4(114-135) with the SUV membrane. The K(d) of NSP4(114-135) was determined as well as partitioning of NSP4(114-135) with SUVs in a filtration-binding assay. These data confirmed NSP4 and its active peptide interact with model membranes that mimic caveolae.

Etiology of bloody diarrhea among patients presenting to United States emergency departments: prevalence of Escherichia coli O157:H7 and other enteropathogens

Escherichia coli O157:H7 and other Shiga toxin-producing E. coli (STEC) infections have been associated with bloody diarrhea. The prevalence of enteropathogens among patients with bloody diarrhea was determined by a prospective study at 11 US emergency departments. Eligible patients had bloody stools, > or =3 loose stool samples per 24-h period, and an illness lasting <7 days. Among 873 patients with 877 episodes of bloody diarrhea, stool samples for culture were obtained in 549 episodes (62.6%). Stool cultures were more frequently ordered for patients with fever, >10 stools/day, and visibly bloody stools than for patients without these findings. Enteropathogens were identified in 168 episodes (30.6%): Shigella (15.3%), Campylobacter (6.2%), Salmonella (5.8%), STEC (2.6%), and other (1.6%). Enteropathogens were isolated during 12.5% of episodes that physicians thought were due to a noninfectious cause. The prevalence of STEC infection varied by site from 0% to 6.2%. Hospital admissions resulted from 195 episodes (23.4%). These data support recommendations that stool samples be cultured for patients with acute bloody diarrhea.

Gastrointestinal infections in children

Gastrointestinal infections in children are a major cause of morbidity and mortality worldwide. Children living in developing countries are particularly susceptible to infectious diarrhea because of poor standards of hygiene and sanitation. Although the magnitude of diarrheal illnesses in developed countries is less, costly hospital admissions are still frequent. The causal agent of infectious diarrhea is most frequently related to age, geographical location, lifestyle habits, use of antibiotics, associated medical conditions, social circumstances, and degree of immune competence. In this article we present some of the most important articles published in the field during the last year. The role of Helicobacter pylori in the pathogenesis of gastritis and peptic ulcer disease has been shown in adults and children. Information about the natural history of H. pylori, symptomatology, and diagnostic therapeutic approaches for children are being generated constantly; we discuss some of the most relevant information in this review.

Etiology of acute diarrhea among children in Ribeirão Preto-SP, Brazil

To study the main enteropathogens causing diarrhea in the region of Ribeirão Preto regarding serogroups and serotypes, the feces of 1836 children under 10 years old, from both sexes, attack of acute gastroenteritis, were analysed during a period of 4 years in Adolfo Lutz Institute - Ribeirão Preto, SP. The pathogens identified by standard methods were the following: Escherichia coli, Salmonella spp., Shigella spp., Campylobacter spp., Yersinia spp., and Cryptosporidium spp. Positive samples were 22.8% (419) with 1.7% association of pathogens. Larger isolates were mainly from children 0 to 11 months old. Enteropathogenic E. coli (EPEC) was most frequent (8.7%) with predominance of serogroup O119 (40.2%), followed by Shigella (6.2%), 63.6% of which S. sonnei.

Diagnosis of noncultivatable gastroenteritis viruses, the human caliciviruses

Gastroenteritis is one of the most common illnesses of humans, and many different viruses have been causally associated with this disease. Of those enteric viruses that have been established as etiologic agents of gastroenteritis, only the human caliciviruses cannot be cultivated in vitro. The cloning of Norwalk virus and subsequently of other human caliciviruses has led to the development of several new diagnostic assays. Antigen detection enzyme immunoassays (EIAs) using polyclonal hyperimmune animal sera and antibody detection EIAs using recombinant virus-like particles have supplanted the use of human-derived reagents, but the use of these assays has been restricted to research laboratories. Reverse transcription-PCR assays for the detection of human caliciviruses are more widely available, and these assays have been used to identify virus in clinical specimens as well as in food, water, and other environmental samples. The application of these newer assays has significantly increased the recognition of the importance of human caliciviruses as causes of sporadic and outbreak-associated gastroenteritis.

Helicobacter pylori colonization and diarrhoeal illness: results of a population-based cross-sectional study in adults

It has been suggested that Helicobacter pylori colonization may protect against diarrhoeagenic gastrointestinal infections. The aim of this analysis was to investigate the association between H. pylori infection and the frequency of diarrhoeal episodes among adults. Helicobacter pylori infection status was determined by 13C-urea breath test. Overall, 784 adults (mean age: 48.7 +/- 17.7; range 18-85 years) who participated in two epidemiological studies were included in the analysis. Overall H. pylori prevalence was 25.5%. Episodes of diarrhoea within prior 3 months were less often reported for H. pylori infected subjects compared with H. pylori negative subjects (40.2 vs. 51.6%, p = 0.016). Compared to H. pylori negative subjects the odds ratio (OR) for the occurrence of diarrhoea within the prior 3 months was 0.63 (95% CI: 0.45-0.87) for H. pylori infected subjects. After adjustment for covariates the OR was 0.67 (95% CI: 0.47-0.95). These results support the hypothesis that colonization with H. pylori may protect from gastrointestinal infections that cause diarrhoea.

Gastroenteritis in sentinel general practices,The Netherlands

From 1996 to 1999, the incidence of gastroenteritis in general practices and the role of a broad range of pathogens in the Netherlands were studied. All patients with gastroenteritis who had visited a general practitioner were reported. All patients who had visited a general practitioner for gastroenteritis (cases) and an equal number of patients visiting for nongastrointestinal symptoms (controls) were invited to participate in a case-control study. The incidence of gastroenteritis was 79.7 per 10,000 person years. Campylobacter was detected most frequently (10% of cases), followed by Giardia lamblia (5%), rotavirus (5%), Norwalk-like viruses (5%) and Salmonella (4%). Our study found that in the Netherlands (population 15.6 million), an estimated 128,000 persons each year consult their general practitioner for gastroenteritis, slightly less than in a comparable study in 1992 to 1993. A pathogen could be detected in almost 40% of patients (bacteria 16%, viruses 15%, parasites 8%).

Epidemiology and predictors of infant morbidity in rural Malawi

In rural Malawi, 703 newborns were visited monthly for 1 year to describe the epidemiology and health-seeking behaviour during acute episodes of diarrhoea, respiratory infections (ARI) and malaria. On average, the infants suffered from 1.3 annual episodes (11.0 illness days) of diarrhoea, 1.1 episodes (9.4 days) of ARI and 0.7 episodes (4.8 days) of malaria. Multivariate analysis with polychotomous logistic regression indicated that the amount of morbidity was associated with the child's area of residence, weight in early life, number of siblings, father's marital status and the source of drinking water. Diarrhoea and malaria were most common at 6-12 months of age and during the rainy months whereas respiratory infections peaked at 1-3 months of age and in the cold season. Ten per cent of diarrhoea, 9% of ARI and 7% of malaria episodes lasted for more than 14 days. Fifty-eight infants died, giving case fatality rates of 1% for diarrhoea, 2% for ARI and 4% for malaria. One-third (37%) of the illness episodes were managed at home without external advice. A traditional healer was consulted in 16% of episodes and a medical professional in 55% of episodes. If consulted, traditional healers were seen earlier than medical professionals (median duration after the onset of symptoms 0.7 vs. 1.8 days, P < 0.001). Traditional healers were significantly more commonly used by those families whose infants died than by those whose infants did not die (odds ratio 1.8, 95% CI 1.1, 3.0). Our results emphasise the influence of seasonality, care and living conditions on the morbidity of infants in rural Malawi. Case fatality for diarrhoea, ARI and malaria was high and associated with health-seeking behaviour among the guardians. Future interventions must aim at early and appropriate management of common childhood illnesses during infancy.

Enteropathogens in adult patients with diarrhea and healthy control subjects: a 1-year prospective study in a Swedish clinic for infectious diseases

A 1-year prospective study was conducted to identify enteropathogens in adults with diarrhea (n=851) and in healthy control subjects (n=203) by use of conventional laboratory methods. Virulence factor genes for diarrheagenic Escherichia coli were detected by polymerase chain reaction. Enteropathogens were identified in 56% of patients and 16% of control subjects. The isolation rate was 65% for patients with symptoms for <1 week and for travelers; >1 pathogen was found in 11% of patients. The most frequent enteropathogens were Campylobacter (13% of patients), Clostridium difficile (13%), enterotoxigenic Escherichia coli (8%), Salmonella (7%), Shigella (4%), Blastocystis hominis (4%), calicivirus (3%), rotavirus (3%), enteroaggregative E. coli (2%), Aeromonas (2%), Giardia intestinalis (2%), Cryptosporidium (2%), and astrovirus (2%). Less frequently isolated (< or =1% of patients) were verotoxigenic E. coli, enteropathogenic E. coli, enteroinvasive E. coli, Entamoeba histolytica/Entamoeba dispar, microsporidia, and adenovirus. Fifty percent of the patients were hospitalized, and 43% needed intravenous fluids. The median duration of diarrhea was 14 days. Clinical features were not helpful for predicting the etiology of diarrhea.

Asymptomatic carriage of Clostridium difficile and serum levels of IgG antibody against toxin A

BACKGROUND

Clostridium difficile infection can result in asymptomatic carriage, mild diarrhea, or fulminant pseudomembranous colitis. We studied whether antibody responses to C. difficile toxins affect the risks of colonization, diarrhea, and asymptomatic carriage.

METHODS

We prospectively studied C. difficile infections in hospitalized patients who were receiving antibiotics. Serial stool samples were tested for C. difficile colonization by cytotoxin assay and culture. Serum antibody (IgA, IgG, and IgM) levels and fecal antibody (IgA and IgG) levels against C. difficile toxin A, toxin B, and nontoxin antigens were measured by an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Of 271 patients, 37 (14 percent) were colonized with C. difficile at the time of admission, 18 of whom were asymptomatic carriers. An additional 47 patients (17 percent) became infected in the hospital, 19 of whom remained asymptomatic. The baseline antibody levels were similar in the patients who later became colonized and those who did not. After colonization, those who became asymptomatic carriers had significantly greater increases in serum levels of IgG antibody against toxin A than did the patients in whom C. difficile diarrhea developed (P<0.001). The adjusted odds ratio for diarrhea was 48.0 (95 percent confidence interval, 3.4 to 678) among patients with colonization who had a serum level of IgG antibody against toxin A of 3.00 ELISA units or less, as compared with patients with colonization who had a level of more than 3.00 ELISA units.

CONCLUSIONS

We find no evidence of immune protection against colonization by C. difficile. However, after colonization there is an association between a systemic anamnestic response to toxin A, as evidenced by increased serum levels of IgG antibody against toxin A, and asymptomatic carriage of C. difficile.

Syntaxin 1A is expressed in airway epithelial cells, where it modulates CFTR Cl(-) currents

The CFTR Cl(-) channel controls salt and water transport across epithelial tissues. Previously, we showed that CFTR-mediated Cl(-) currents in the Xenopus oocyte expression system are inhibited by syntaxin 1A, a component of the membrane trafficking machinery. This negative modulation of CFTR function can be reversed by soluble syntaxin 1A peptides and by the syntaxin 1A binding protein, Munc-18. In the present study, we determined whether syntaxin 1A is expressed in native epithelial tissues that normally express CFTR and whether it modulates CFTR currents in these tissues. Using immunoblotting and immunofluorescence, we observed syntaxin 1A in native gut and airway epithelial tissues and showed that epithelial cells from these tissues express syntaxin 1A at >10-fold molar excess over CFTR. Syntaxin 1A is seen near the apical cell surfaces of human bronchial airway epithelium. Reagents that disrupt the CFTR-syntaxin 1A interaction, including soluble syntaxin 1A cytosolic domain and recombinant Munc-18, augmented cAMP-dependent CFTR Cl(-) currents by more than 2- to 4-fold in mouse tracheal epithelial cells and cells derived from human nasal polyps, but these reagents did not affect CaMK II-activated Cl(-) currents in these cells.

Characterization of Escherichia coli strains from cases of childhood diarrhea in provincial southwestern Nigeria

In a study carried out in small-town and rural primary health care centers in southwestern Nigeria, 330 Escherichia coli strains isolated from 187 children with diarrhea and 144 apparently healthy controls were examined for virulence traits. Based on the results of colony blot hybridization, strains were categorized as enteropathogenic E. coli (1.8%), enterotoxigenic E. coli (2.4%), enteroinvasive E. coli (1.2%), enterohemorrhagic E. coli (0.6%), enteroaggregative E. coli (10.3%), diffusely adherent E. coli (7.9%), cell-detaching E. coli (6.9%), and cytolethal distending toxin-producing E. coli (0.9%). E. coli strains that hybridized with a Shiga toxin gene probe but lacked other characteristics usually present in enterohemorrhagic E. coli constituted 8.4% of the isolates. Ninety-seven E. coli isolates adhered to HEp-2 cells in an aggregative fashion but did not hybridize with any of the probes employed in the study. Overall the pathotypes, apart from cytolethal distending toxin-producing E. coli, were recovered both from children with diarrhea and from children without diarrhea, though to a lower extent from the healthy children. All diarrheagenic E. coli strains were associated with diarrhea (P < 0.02). Heat-stable-enterotoxin-producing enterotoxigenic E. coli showed significant association with diarrhea (P < 0.02), as did strains that demonstrated aggregative adherence to HEp-2 cells (P < 0.04), but not those that hybridized with the CVD432 enteroaggregative probe.

Drugs for treating giardiasis

BACKGROUND

There can be a high rate of recurrence of disease after initial drug treatment for giardiasis. These drugs also have a range of adverse effects.

OBJECTIVES

The objective of this review was to assess the effects of drug treatments for giardiasis.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group trials register, the Cochrane Controlled Trials Register, Medline and Embase, Current Contents, reference lists of articles.

SELECTION CRITERIA

Randomised and quasi-randomised trials of drug therapy for giardiasis compared with placebo or another drug.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data.

MAIN RESULTS

Thirty-four trials were included. Only one trial was without serious methodological flaws. Compared with placebo, drug treatment was associated with an improved cure rate (odds ratio 11.5, 95% confidence interval 2.3 to 58). Metronidazole treatment longer than three days had a better parasitological cure rate than other long treatment courses (odds ratio 2.4, 95% confidence interval 1.3 to 4.4), but there was significant heterogeneity between the trials. Single dose therapy appeared equally effective as longer treatment courses (odds ratio 0.33, 95% confidence interval 0.08 to 1.34). Within the single dose regimens, tinidazole had a comparable parasitological cure rate to other short therapies (odds ratio 3.4, 95% confidence interval 0.95 to 12), but had a higher clinical cure rate (odds ratio 5.3, 95% 2.7-10.7).

REVIEWER'S CONCLUSIONS

A single dose of tinidazole appears to give the highest clinical cure rate for giardiasis with relatively few adverse effects.

Maternal knowledge and environmental factors associated with risk of diarrhea in Israeli Bedouin children

Diarrhea is still a major cause of morbidity and mortality among children in developing countries. As it is due to multiple causative agents including viruses, bacteria and parasites, biological interventions are not currently available to markedly reduce incidence and severity. We examined maternal knowledge and reported behavior during diarrheal episodes, as well as environmental factors to determine their association with diarrhea. The children and mothers were from a Bedouin township in southern Israel, which has developed preventive and curative health care facilities. The Bedouin population in Israel is in transition from a nomadic to a settled life style. While almost all mothers exhibited good knowledge regarding food storage and prevention of diarrhea episodes in the children, the rate of illness in the children remained relatively high (two episodes per child year of observation). In a multivariate analysis, cessation of breastfeeding during diarrhea, child sleeping with siblings and lack knowledge about risk factors, were the major risk factors for illness with odds ratios (OR): 4.6, p = 0.02, 5.6, p = 0.03 and 1.7, p = 0.06, respectively. These data indicate that even in this population with free access to preventive medical care, greater efforts should be made to educate mothers regarding risk factor for diarrheal disease identification and the benefits of maintaining breastfeeding during diarrhea episodes.

Gastrointestinal symptoms and use of medical care associated with child day care and health care plan among preschool children

OBJECTIVES

This study examined whether out-of-home day care increases the risk of gastrointestinal symptoms for children <6 years of age and whether there is an association between gastrointestinal symptoms and medical care utilization.

METHODS

The study population comprised members of 2 health plans residing in 2 South Carolina counties: 417 families from an health maintenance organization (HMO) plan; and 643 families from a Medicaid plan. Participants were followed for 18 months by either bimonthly telephone interviews or personal interviews. The survey/interview collected familial, personal, day-care and disease-related information and medical care utilization. The analyses controlled for both family characteristics and the type of health care plan.

RESULTS

Children attending out-of-home day care had higher incidence rates for most gastrointestinal symptoms studied than did children staying at home (2.51 vs. 1.61 episodes of mild gastrointestinal symptoms and 1.63 vs. 1.08 episodes of moderate gastrointestinal symptoms for the HMO group; 1.72 vs. 1.28 episodes of moderate gastrointestinal symptoms for the Medicaid group). Nearly one-fourth of the annual physician visits by children younger than 6 years were attributed to gastrointestinal symptoms, and more than one-fourth of the children with gastrointestinal symptoms were prescribed antibiotics. When displaying gastrointestinal symptoms, children in the Medicaid group were significantly more likely to visit a doctor and receive antibiotics than those in the HMO group.

CONCLUSIONS

Although the type of health plan has negligible influence on the frequency of reported gastrointestinal symptoms, it exerts a strong influence on medical care utilization.

Interruption of transmembrane signaling as a novel antisecretory strategy to treat enterotoxigenic diarrhea

Bacteria that produce heat-stable enterotoxins (STs), a leading cause of secretory diarrhea, are a major cause of morbidity and mortality worldwide. ST stimulates guanylyl cyclase C (GCC) and accumulation of intracellular cyclic GMP ([cGMP]i), which opens the cystic fibrosis transmembrane conductance regulator (CFTR)-related chloride channel, triggering intestinal secretion. Although the signaling cascade mediating ST-induced diarrhea is well characterized, antisecretory therapy targeting this pathway has not been developed. 2-ChloroATP (2ClATP) and its cell-permeant precursor, 2-chloroadenosine (2ClAdo), disrupt ST-dependent signaling in intestinal cells. However, whether the ability to disrupt guanylyl cyclase signaling translates into effective antisecretory therapy remains untested. In this study, the efficacy of 2ClAdo to prevent ST-induced water secretion by human intestinal cells was examined. In Caco-2 human intestinal cells, ST increased [cGMP]i, induced a chloride current, and stimulated net basolateral-to-apical water secretion. This effect on chloride current and water secretion was mimicked by the cell-permeant analog of cGMP, 8-bromo-cGMP. Treatment of Caco-2 cells with 2ClAdo prevented ST-induced increases in [cGMP]i, chloride current and water secretion. Inhibition of the downstream consequences of ST-GCC interaction reflects proximal disruption of cGMP production because 8-bromo-cGMP stimulated chloride current and water secretion in 2ClAdo-treated cells. Thus, this study demonstrates that disruption of guanylyl cyclase signaling is an effective strategy for antisecretory therapy and provides the basis for developing mechanism-based treatments for enterotoxigenic diarrhea.

A placebo-controlled trial of Lactobacillus GG to prevent diarrhea in undernourished Peruvian children

OBJECTIVE

Lactobacillus GG (L-GG), an acid- and bile-resistant strain that colonizes the intestinal mucosa, has been used to manage diarrhea in children. Our objective was to evaluate the prophylactic use of L-GG to prevent diarrhea in children at high risk from a developing country in a randomized, placebo-controlled trial.

STUDY DESIGN

Two hundred four undernourished children 6 to 24 months old from an indigent peri-urban Peruvian town received either L-GG or placebo in flavored gelatin once daily, 6 days a week, for 15 months. Episodes of diarrhea were documented by daily home visits, and diagnostic studies were done in a subset of cases. Recovery of L-GG in stool from subjects and from family contacts was examined.

RESULTS

Subjects in the L-GG group had significantly fewer episodes of diarrhea (5.21 episodes diarrhea/child/year ['ecy'] L-GG group, 6. 02 ecy placebo group; P =.028). The decreased incidence of diarrhea in the L-GG group was greatest in the 18- to 29-month age group (P =. 004) and was largely limited to nonbreastfed children (Breastfed: 6. 59 ecy L-GG, 6.32 ecy placebo, P =.7; Nonbreastfed: 4.69 ecy L-GG, 5. 86 ecy placebo, P =.005). The duration of diarrhea episodes and the causes of diarrhea were similar in both groups, except adenovirus was more common in the placebo group.

CONCLUSION

L-GG supplementation may be useful as a prophylactic measure to control diarrhea in undernourished children at increased risk, especially nonbreastfed children in the toddler age group.

Nutritional management of acute diarrhea

Despite recommendations from several bodies such as the World Health Organization and others that feeding should be continued during diarrhea, the practice of withholding food during the early stages of diarrhea is still widespread. This contributes to a deterioration in patients' nutritional state. The principal controversy in the nutritional therapy of acute gastroenteritis centers on the relative risks of cows'-milk feeds. The two things that need to be considered in determining the optimum approach to feeding the child with acute diarrhea are the optimum timing for feeding children in relation to the onset of and recovery from symptoms and, secondly, the effects of specific food ingredients in the diet. Recent studies have demonstrated that the vast majority of young children with acute diarrhea can be successfully managed with continued feeding of undiluted non-human milk. Routine dilution of milk and routine use of lactose-free formula are not necessary, especially when oral rehydration therapy and early feeding (in addition to milk) form the basic approach to the clinical management of diarrhea in children. Confounding factors are the severity of the diarrhea, coexistent malnutrition, and young age (< 1 y); such infants are much more likely to have complications from early feeding with undiluted milk and some would advocate use of specifically designed lactose-free formula in such children. Children who are fed exclusively with human milk and those who receive solid foods with or without human milk may safely continue to receive their usual diets during diarrhea. Those who are fed exclusively with non-human milk--especially when very young and with severe diarrhea or malnutrition--should be closely observed if they continue to consume milk or they should receive a special formulation (e.g., a cereal-milk mixture or fermented milk product). The use of nutrient-dense mixtures of common foods may be advisable to promote compensatory growth in those who lose weight during illness or because of anorexia or malabsorption.

Hospitalizations for infectious diseases in Jewish and Bedouin children in southern Israel

Two different population groups reside in the Negev region of southern Israel and have equal, and free from financial barrier, access to tertiary care at a single regional hospital. The Jewish population has a largely urban and industrialized lifestyle, while the Moslem Bedouins are in transition from their traditional nomadic life to settlement. To examine the differences in morbidity patterns reflected in hospitalizations, the computerized hospitalization records of children <15 years of age, for 1989-1991 were used (n=15,947). Rates of hospitalizations for infectious diseases were significantly higher for Bedouins in comparison to Jews (250 and 121/10,000 child years, respectively, odds ratio (OR): 2.1, 95% confidence interval (CI): 2.0-2.2, p < 0.001). Rates of hospitalization per 10,000 child years in Bedouins and Jews for diarrhea were 114 and 32 (OR: 3.7, 95% CI: 3.3-4.0, p < 0.001), respectively, and for pneumonia 55 and 19 (OR: 2.9, 95% CI: 2.6-3.3, p < 0.001), respectively. In infants the differences were even more pronounced, especially for diarrheal diseases. In Bedouin children infectious diseases were associated with longer hospital stay, more pediatric Intensive Care hospitalizations (OR: 2.7, 95% CI: 1.7-4.5,p < 0.001), and higher in-hospital mortality (OR: 5.7, 95% CI: 2.8-12.2, p < 0.001). Thus, Bedouin children are at higher risks of hospitalizations for infectious diseases in early childhood, as compared to Jewish children. This may reflect the differences in lifestyle, environmental and social conditions of the two populations.

Epidemiological study on infectious diarrheal diseases in children in a coastal rural area of Kenya

Diarrheal diseases are major causes of morbidity and mortality among children in developing countries. We have analyzed the causative agents of diarrhea in children under five years of age who resided in rural environments but attended a hospital in Malindi, a coastal town in Kenya. Bacterial diarrhea was found in 239 (27.7%) of 862 patients with diarrhea. Diarrheagenic Escherichia coli, including enteropathogenic, enterotoxigenic, and enterohaemorrhagic strains, was isolated from 119 (13.8%) patients, followed by Salmonella spp. (63 cases, 7.3%) and Shigella spp. (56 cases, 6.5%). Intestinal parasites were found in 109 (12.6%) of the patients. Entamoeba histolytica and Giardia lamblia were found in 67 (7.8%) and 42 (4.9%) of the cases, respectively. Rotavirus was found in 69 (16.1%) of 428 cases, a part of the 862 cases. Significant differences in age distribution were seen in diarrheal cases due to Campylobacter spp., G. lamblia, and rotavirus. No significant seasonal incidence of specific pathogens was found, but the number of diarrheal patients was significantly correlated to rainfall. Drinking water was contaminated with bacteria at concentrations ranging from 10(3) to 10(6) CFU/ml in 98% of the households and by coliform bacteria at concentrations of 10(2) to 10(5) CFU/ml in 72% of the households. These results suggest that the main routes of infection may be contaminated drinking water and fecal-oral transmission of enteric pathogens. Consequently, we propose that the enhancement of hygienic practice through health education is a feasible control measure of diarrhea in the study area.

Etiological agents of infectious diarrhea: implications for requests for microbial culture

Gastrointestinal infections remain a frequent disease worldwide. In order to increase our knowledge of the epidemiology for our patient population, we retrospectively analyzed the results obtained for stool samples received at the clinical microbiology laboratory of the University Hospital of Geneva during a 4-year period. A total of 13,965 specimens from 7,124 patients (1.96 specimens per patient) were cultured, yielding 369 (2.6%) Salmonella spp., 408 (2.9%) Campylobacter spp., and 79 (0.6%) Shigella spp. The cumulative positivity rate of 6.1% decreased to 2.7% when patients received antimicrobial agents (P < 0.001). The positivity rate for 5,912 specimens obtained from patients hospitalized for < or = 3 days was 12.6%, whereas it dropped to 1.4% for patients hospitalized for > 3 days (P < 0.001). Of 3,837 stool samples originating from pediatric patients, 8.8% were positive, and 5.1% of 10,128 samples from adults were positive (P < 0.001). The cytotoxin of Clostridium difficile was detected in 379 of 3,723 samples analyzed (10.2%), and rotaviruses were detected in 190 of 1,601 samples (11.9%). We recommend that the use of cultures for enteric bacterial pathogens be restricted to patients hospitalized for < or = 3 days, with the exceptions of follow-up samples, specimens from immunocompromised patients, and patients whose first sample was culture negative or in the rare event of nosocomial food-borne outbreaks. For patients under antimicrobial therapy, testing for cytotoxin of C. difficile should primarily be requested; this analysis should also be accepted for samples from patients not receiving antimicrobial agents at the time of specimen collection. By applying these restrictions, we could have saved at least $5,000 annually.

Infectious Diarrhea

Infectious diarrhea constitutes a major source of morbidity and mortality for all age groups. The focus of this article is to identify high risk host and pathogenic risk determinants of enteric infections, discuss pathophysiologic mechanisms for diarrhea, review conventional and upcoming therapeutic managements of bacterial, protozoal or viral-type diarrhea, and describe the integral role of the pharmacist in the overall care of patients having this illness.

Bacteroides fragilis toxin rapidly intoxicates human intestinal epithelial cells (HT29/C1) in vitro

Enterotoxigenic Bacteroides fragilis strains associated with childhood diarrhea produce a 20-kDa protein toxin (BFT). Purified BFT causes striking morphologic changes in subconfluent human colonic epithelial cells (HT29/C1). In a 3-h HT29/C1 cell assay, the estimated half-maximal effective concentration of BFT was 12.5 pM, and morphologic effects were detectable as early as 30 min and nearly complete by 1.5 h. Concentrations as low as 0.5 pM could also cause intoxication, but morphologic changes were detectable only when the assay was extended to 18 h. The onset of this intoxication was concentration dependent and rapid, occurring within minutes (<7 min at 0.25 nM, <2 min at 2.5 nM). Notably, the onset of intoxication at 37 degrees C became irreversible to washing within 2 min after exposure to BFT. Morphologic changes were completely inhibited by treatment of HT29/C1 cells with BFT at 4 degrees C but could be demonstrated by subsequent warming to temperatures of 15 degrees C or higher after washing. The time required for the association of BFT with HT29/C1 cells at 4 degrees C was inversely correlated with concentration. Inhibitors of endosomal and Golgi trafficking (NH4Cl and brefeldin A) prevented the intoxication of HT29/C1 cells by Clostridium difficile toxin A and cholera toxin, respectively, but not by BFT. Agents altering microtubule structure did not affect the cellular activity of BFT. These data indicate that a purified toxin from B. fragilis strains associated with diarrhea rapidly and irreversibly intoxicates human intestinal epithelial cells (HT29/C1) in a concentration- and temperature-dependent manner and that the process of intoxication may not involve internalization mechanisms utilizing microtubules or sensitive to pH or brefeldin A.

Enteropathogens associated with childhood diarrhea in Italy. The Italian Study Group on Gastrointestinal Infections

BACKGROUND

Infectious diarrheal diseases remain an important cause of childhood morbidity in industrialized countries. The knowledge of the etiology and epidemiology of childhood diarrhea in a given area is needed to plan any measure designed to prevent or ameliorate diarrheal illness and to develop practice guidelines for the most appropriate stool examination procedures.

METHODS

We evaluated 618 children with diarrhea and 135 controls prospectively for viral, bacterial and parasitic enteric pathogens. Diarrheagenic Escherichia coli was identified by gene probes specific to different virulence factors. Stool filtrates were examined for the presence of free bacterial toxins by a cell culture cytotoxicity assay. Clinical and epidemiologic data were recorded and analyzed in relation to microbiologic findings.

RESULTS

Enteropathogens were identified in 59% of children with diarrhea and in 10.4% of asymptomatic controls. The agents mainly associated with disease were rotavirus (23.6%), Salmonella (19.2%) and Campylobacter (7.9%). Rotavirus was significantly more frequent among children observed as inpatients whereas Campylobacter was significantly more common in outpatients. Infections with diarrheagenic E. coli, Shigella flexneri, yersinia enterocolitica, Cryptosporidium and Giardia were observed in a limited number of patients. The clinical presentation of children was not sufficiently characteristic to permit presumptive diagnosis of a specific pathogen. conversely the presence of blood and/or leukocytes in stools had a high positive predictive value for Salmonella or Campylobacter infection.

CONCLUSION

The results of this study will be useful for planning strategies to prevent and control diarrheal diseases in our country.