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

Antimicrobial resistance and management of invasive Salmonella disease

Invasive Salmonella infections (typhoidal and non-typhoidal) cause a huge burden of illness estimated at nearly 3.4 million cases and over 600,000 deaths annually especially in resource-limited settings. Invasive non-typhoidal Salmonella (iNTS) infections are particularly important in immunosuppressed populations especially in sub-Saharan Africa, causing a mortality of 20-30% in vulnerable children below 5 years of age. In these settings, where routine surveillance for antimicrobial resistance is rare or non-existent, reports of 50-75% multidrug resistance (MDR) in NTS are common, including strains of NTS also resistant to flouroquinolones and 3rd generation cephalosporins. Typhoid (enteric) fever caused by Salmonella Typhi and Salmonella Paratyphi A remains a major public health problem in many parts of Asia and Africa. Currently over a third of isolates in many endemic areas are MDR, and diminished susceptibility or resistance to fluoroquinolones, the drugs of choice for MDR cases over the last decade is an increasing problem. The situation is particularly worrying in resource-limited settings where the few remaining effective antimicrobials are either unavailable or altogether too expensive to be afforded by either the general public or by public health services. Although the prudent use of effective antimicrobials, improved hygiene and sanitation and the discovery of new antimicrobial agents may offer hope for the management of invasive salmonella infections, it is essential to consider other interventions including the wider use of WHO recommended typhoid vaccines and the acceleration of trials for novel iNTS vaccines. The main objective of this review is to describe existing data on the prevalence and epidemiology of antimicrobial resistant invasive Salmonella infections and how this affects the management of these infections, especially in endemic developing countries.

Flooding and Clostridium difficile Infection: A Case-Crossover Analysis

Clostridium difficile is a bacterium that can spread by water. It often causes acute gastrointestinal illness in older adults who are hospitalized and/or receiving antibiotics; however, community-associated infections affecting otherwise healthy individuals have become more commonly reported. A case-crossover study was used to assess emergency room (ER) and outpatient visits for C. difficile infection following flood events in Massachusetts from 2003 through 2007. Exposure status was based on whether or not a flood occurred prior to the case/control date during the following risk periods: 0-6 days, 7-13 days, 14-20 days, and 21-27 days. Fixed-effects logistic regression was used to estimate the risk of diagnosis with C. difficile infection following a flood. There were 129 flood events and 1575 diagnoses of C. difficile infection. Among working age adults (19-64 years), ER and outpatient visits for C. difficile infection were elevated during the 7-13 days following a flood (Odds Ratio, OR = 1.69; 95% Confidence Interval, CI: 0.84, 3.37). This association was more substantial among males (OR = 3.21; 95% CI: 1.01-10.19). Associations during other risk periods were not observed (p < 0.05). Although we were unable to differentiate community-associated versus nosocomial infections, a potential increase in C. difficile infections should be considered as more flooding is projected due to climate change.

Role of noroviruses as aetiological agents of diarrhoea in developing countries

Diarrhoea is considered to be the second leading cause of death due to infections among children  < 5 years of age worldwide that may be caused by bacteria, parasites, viruses and non-infectious agents. The major causative agents of diarrhoea in developing countries may vary from those in developed countries. Noroviruses are considered to be the most common cause of acute diarrhoea in both children and adults in industrialized countries. On the other hand, there is a lack of comprehensive epidemiological evidence from developing countries that norovirus is a major cause of diarrhoea. In these regions, asymptomatic norovirus infections are very common, and similar detection rates have been observed in patients with diarrhoea and asymptomatic persons. This review summarizes the current knowledge of norovirus infection in developing countries and seeks to position infections with noroviruses among those of other enteropathogens in terms of disease burden in these regions.

Infections by Intestinal Coccidia and Giardia duodenalis

The coccidians Cryptosporidium spp, Cyclospora cayetanensis, and Cystoisospora belli and the flagellate Giardia duodenalis are pathogenic protozoa associated with gastrointestinal manifestations. Diagnosis relies heavily on microscopy, and although ova-and-parasite examinations can detect Giardia and Cystoisospora, Cryptosporidium and Cyclospora often require specific diagnostic requests. Approved non-microscopy methods are available for Giardia and Cryptosporidium, although negative results are frequently followed by microscopic assays. Polymerase chain reaction-based methods are not frequently used for diagnosis of Giardia and Cryptosporidium and have been used primarily for epidemiologic or outbreak investigations of Giardia and Cryptosporidium.

Epidemiology of Clostridium difficile: a hospital-based descriptive study in Argentina and Mexico

A prospective study was conducted in four tertiary hospitals in Argentina and Mexico in order to describe the occurrence of Clostridium difficile infection (CDI) in these settings. The objective was to evaluate the incidence of CDI in at-risk populations in Argentina (one center) and Mexico (three centers) and to further explore potential study sites for vaccine development in this region. A prospective, descriptive, CDI surveillance study was conducted among hospitalized patients aged ≥40 years who had received ≥48 h of antibiotic treatment. Stool samples were collected from those with diarrhea within 30 days after starting antibiotics and analyzed for toxins A and B by ELISA, and positive samples were further tested by toxinogenic culture and restriction endonuclease analysis type assay. Overall, 466 patients were enrolled (193 in Argentina and 273 in Mexico) of whom 414 completed the follow-up. Of these, 15/414 (3.6%) experienced CDI episodes occurring on average 18.1 days after admission to hospital and 15.9 days after the end of antibiotics treatment. The incidence rate of CDI was 3.1 (95% CI 1.7–5.2) per 1000 patient-days during hospitalization, and 1.1 (95% CI 0.6–1.8) per 1000 patient-days during the 30-day follow-up period. This study highlighted the need for further evaluation of the burden of CDI in both countries, including the cases occurring after discharge from hospital.

Hygienic conditions in child-care facilities in North Carolina and South Carolina: an integrated microbial and observational study

BACKGROUND

In the United States almost one-quarter (23%) of children younger than age 5 years participate in some form of out-of-home child care; these children are 2.3-3.5 times more likely to contract acute gastrointestinal illness.

METHODS

Observational investigations were done to understand the hygienic conditions and practices of 40 child-care facilities in North Carolina and South Carolina. These data were compared with microbiological indicator data (aerobic plate counts and coliform counts) collected from selected surfaces in each facility. Results from the two data sets were analyzed using nonparametric statistical methods to reveal potential risk factors for enteric disease transmission.

RESULTS

Statistically significant differences (P ≤ .05) in surface microbial counts were observed when comparing family child-care homes versus centers and between facilities participating in the Child and Adult Care Food Program and those that do not participate. Facilities without written surface cleaning or food preparation policies had statistically significantly higher microbial counts on surfaces.

CONCLUSIONS

Our unique study, which combined observational and microbiological data, provided revealing information about the relationship between hygiene indicators and sanitary practices in child-care facilities in the southeastern United States.

Effect of non-stationary climate on infectious gastroenteritis transmission in Japan

Local weather factors are widely considered to influence the transmission of infectious gastroenteritis. Few studies, however, have examined the non-stationary relationships between global climatic factors and transmission of infectious gastroenteritis. We analyzed monthly data for cases of infectious gastroenteritis in Fukuoka, Japan from 2000 to 2012 using cross-wavelet coherency analysis to assess the pattern of associations between indices for the Indian Ocean Dipole (IOD) and El Niño Southern Oscillation (ENSO). Infectious gastroenteritis cases were non-stationary and significantly associated with the IOD and ENSO (Multivariate ENSO Index [MEI], Niño 1 + 2, Niño 3, Niño 4, and Niño 3.4) for a period of approximately 1 to 2 years. This association was non-stationary and appeared to have a major influence on the synchrony of infectious gastroenteritis transmission. Our results suggest that non-stationary patterns of association between global climate factors and incidence of infectious gastroenteritis should be considered when developing early warning systems for epidemics of infectious gastroenteritis.

Preponderance of toxigenic Escherichia coli in stool pathogens correlates with toxin detection in accessible drinking-water sources

Since early detection of pathogens and their virulence factors contribute to intervention and control strategies, we assessed the enteropathogens in diarrhoea disease and investigated the link between toxigenic strains of Escherichia coli from stool and drinking-water sources; and determined the expression of toxin genes by antibiotic-resistant E. coli in Lagos, Nigeria. This was compared with isolates from diarrhoeal stool and water from Wisconsin, USA. The new Luminex xTAG GPP (Gastroplex) technique and conventional real-time PCR were used to profile enteric pathogens and E. coli toxin gene isolates, respectively. Results showed the pathogen profile of stool and indicated a relationship between E. coli toxin genes in water and stool from Lagos which was absent in Wisconsin isolates. The Gastroplex technique was efficient for multiple enteric pathogens and toxin gene detection. The co-existence of antibiotic resistance with enteroinvasive E. coli toxin genes suggests an additional prognostic burden on patients.

Incidence of and risk factors for hospital-acquired diarrhea in three tertiary care public hospitals in Bangladesh

During April 2007–April 2010, surveillance physicians in adult and pediatric medicine wards of three tertiary public hospitals in Bangladesh identified patients who developed hospital-acquired diarrhea. We calculated incidence of hospital-acquired diarrhea. To identify risk factors, we compared these patients to randomly selected patients from the same wards who were admitted > 72 hours without having diarrhea. The incidence of hospital-acquired diarrhea was 4.8 cases per 1,000 patient-days. Children < 1 year of age were more likely to develop hospital-acquired diarrhea than older children. The risk of developing hospital-acquired diarrhea increased for each additional day of hospitalization beyond 72 hours, whereas exposure to antibiotics within 72 hours of admission decreased the risk. There were three deaths among case-patients; all were infants. Patients, particularly young children, are at risk for hospital-acquired diarrhea and associated deaths in Bangladeshi hospitals. Further research to identify the responsible organisms and transmission routes could inform prevention strategies.

A study of the prevalence of diarrhoeagenic Escherichia coli in children from Gwagwalada, Federal Capital Territory, Nigeria

Introduction

Diarrhoeagenic Escherichia coli (DEC) are major causes of diarrhoea in Nigeria. This study was conducted to determine the prevalence of diarrhoea caused by DEC within the Federal Capital Territory, Abuja, Nigeria.

Methods

A total of 730 rectal swabs obtained from 201 children with diarrhoea and 529 healthy controls aged 0-24 months were cultured for the isolation of Escherichia coli. All E. coli isolates were investigated by PCR to determine their pathotype.

Results

A total of 61 DEC strains were recovered at a rate of 18.4% and 2.6% from children with diarrhoea and healthy controls respectively. The DEC strains recovered were Enteroaggregative Escherichia coli (34.4%), Shiga-toxin producing Escherichia coli (31.1%), Enterotoxigenic Escherichia coli(18.0%), typical enteropathogenic Escherichia coli (15.0%) and Enteroinvasive Escherichia coli (1.6%). Shiga-toxin producing Escherichia coli andEnteroinvasive Escherichia coli were recovered only from children suffering from diarrhoea and the overall prevalence of DEC strains was significantly higher among the children with diarrhoea (P < 0.0001). The number of DEC strains obtained during the dry season was significantly higher (P = 0.012) than the number obtained in the rainy season.

Conclusion

Diarrhoea caused by E. coli in the Nigerian children studied is associated with several diarrhoeagenic pathotypes and a significant proportion of the healthy children were found to harbour EAEC and ETEC strains. These asymptomatic carriers may be regarded as potential transmitters of infection to vulnerable children in the study area.

High detection rates of enteropathogens in asymptomatic children attending day care

Background

Gastroenteritis morbidity is high among children under the age of four, especially amongst those who attend day care.

Objective

To determine the prevalence of a range of enteropathogens in the intestinal flora of children attending day care and to relate their occurrence with characteristics of the sampled child and the sampling season.

Methods

We performed three years of enteropathogen surveillance in a network of 29 child day care centers in the Netherlands. The centers were instructed to take one fecal sample from ten randomly chosen children each month, regardless of gastrointestinal symptoms at time of sampling. All samples were analyzed for the molecular detection of 16 enteropathogenic bacteria, parasites and viruses by real-time multiplex PCR.

Results

Enteropathogens were detected in 78.0% of the 5197 fecal samples. Of the total, 95.4% of samples were obtained from children who had no gastroenteritis symptoms at time of sampling. Bacterial enteropathogens were detected most often (most prevalent EPEC, 19.9%), followed by parasitic enteropathogens (most prevalent: D. fragilis, 22.1%) and viral enteropathogens (most prevalent: norovirus, 9.5%). 4.6% of samples related to children that experienced symptoms of gastroenteritis at time of sampling. Only rotavirus and norovirus were significantly associated with gastroenteritis among day care attendees.

Conclusions

Our study indicates that asymptomatic infections with enteropathogens in day care attendees are not a rare event and that gastroenteritis caused by infections with these enteropathogens is only one expression of their presence.

Waterborne Viral Gastroenteritis: An Introduction to Common Agents

Acute gastroenteritis is among the most common illnesses of human beings, and its associated morbidity and mortality are greatest among those at the extremes of age; children and elderly. During the 1970s, several viruses were associated with this syndrome, which are now known to be caused mainly by viruses belonging to four distinct families—rotaviruses, caliciviruses, astroviruses, and adenoviruses. Other viruses, such as the toroviruses, picobirnaviruses, coronavirus, and enterovirus 22, may play a role as well. Transmission by food or water has been documented for astroviruses, caliciviruses, rotaviruses, and norovirus. In developing countries, gastroenteritis is a common cause of death in children <5 years, while deaths from diarrhea are less common, much illness leads to hospitalization or doctor visits. Laboratory confirmation of waterborne illness is based on demonstration of virus particles or antigen in stool, detection of viral nucleic acid in stool, or demonstration of a rise in specific antibody to the virus. Newer methods for syndrome surveillance of acute viral gastroenteritis are being developed like multiplex real-time reverse transcriptase PCRs. Application of these more sensitive methods to detect and characterize individual agents is just beginning, but has already opened up new avenues to reassess their disease burden, examine their molecular epidemiology, and consider new directions for their prevention and control through vaccination, improvements in water quality, and sanitary practices.

Bacterial entropathogens and antimicrobial susceptibility in children with acute diarrhea in Babol, Iran

BACKGROUND

Infectious diarrhea is one of common cause of children diarrhea causing mortality and morbidity worldwide. This study was performed to identify the common bacteria and their antimicrobial susceptibility in children with diarrhea.

METHODS

Children under 14 years old with acute diarrhea who referred to Amirkola Children's Hospital, Mazandaran, North of Iran, were enrolled during the summer and fall of 2009. From each patient, two fecal specimens were collected. Samples were cultured and bacterial isolation was done by conventional methods. Antimicrobial susceptibility was identified by disk diffusion and micro dilution methods.

RESULTS

One hundred-seventy two patients with the mean age of 41.8±37.6 months were evaluated. The bacteria were isolated in 48 (27.9%) cases. The most common isolated bacteria was E.coli and then shigella in both bloody and nonbloody diarrheal patients. There was a significant difference between bacteria positive specimens and WBC in stool smear (p=0.003). All isolated shigella were susceptible to Ceftizoxime and ciprofloxacin and were resistant to Cefixime. Resistant to Nalidixic acid was seen in 14% of them.

CONCLUSION

The results show that E.coli was the most frequently isolated pathogen in children with bloody and nonbloody diarrhea. Ceftizoxime is a good antibiotic for shigellosis in children in our area but Cefixime is not appropriate.

Molecular epidemiologic trends of diarrhea-causing virus infection from clinical specimens in Cheonan, Korea, in 2010-2012

BACKGROUND

The enteric viruses have high health significance in humans, ranging from poliomyelitis, hepatitis, and gastroenteritis to innocuous infections, and the human enteric viral infection is the one of the most common diseases during early childhood. This study was conducted from July 2010 to October 2012.

METHODS

We subjected 788 stool specimens using multiplex polymerase chain reaction (mPCR) tests that could simultaneously detect five enteric viruses, group A rotavirus (GAR), enteric adenovirus (EAdV), norovirus GI (NoV-GI), norovirus GII (NoV-GII), and human astrovirus (HAstV). The data were analyzed according to seasonality and patient age and sex.

RESULTS

Two hundred and seventy specimens (34.3%) were positive, 276 viruses were detected in the 788 sample. The prevalence of GAR, EAdV, NoV-GI, NoV-GII, and HAstV infections in the 270 mPCR-positive specimens was 101 (36.6%), 28 (10.1%), 4 (1.4%), 132 (47.8%), and 11 (4.0%), respectively; six specimens (2.2%) contained double infections. NoV-GII and GAR infections occurred mainly in the winter and spring.

CONCLUSION

We described the epidemiological analytic data of the diarrhea-causing viruses in the population of local society of Korea. These results could be helpful for the diagnosis and subsequent epidemiological surveillance of enteric viral infections.

Community-acquired diarrhea among children and adults in urban settings in Senegal: clinical, epidemiological and microbiological aspects

Background

Only limited data are available relating to the etiology of diarrhea in children and adults in Senegal. The aim of this prospective study was to describe the epidemiology and etiology of community-acquired diarrheal infections in children and adults living in urban settings.

Methods

A prospective study was carried out from March 2009 to December 2010, in the urban region of Dakar, Senegal. Patients with acute diarrhea were enrolled, interviewed to collect their clinical history, and their stools were tested for bacteria, virus and parasites.

Results

A total of 223 patients (including 112 children younger than five years old) with diarrhea were included. At least one enteropathogen was detected in 81% (180/223) of the patients: 29% (64/223) had bacterial infections (mainly diarrheagenic E. coli and Shigella spp), 21% (39/185) viral infections (mainly rotavirus) and 14% (31/223) parasitic infections. Co-infection was identified in 17.8% (32/180) of the patients. Viral infection was significantly more frequent in children under five years old during the dry season. Bacteria and parasites were equally frequent in all age groups. There was a seasonal variation of bacterial infections during the study period, with a higher proportion of infections being bacterial, and due to Salmonella spp. in particular, during the rainy season.

Conclusion

Our study suggests that in urban settings in Senegal, rotavirus is the principal cause of pediatric diarrhea during the dry season and that the proportion of bacterial infections seems to be higher during the rainy season. Further work is needed to document the burden of diarrheal diseases in sub-Saharan urban communities and to identify risk factors, including those linked to the rapid and unplanned urbanization in Africa.

Diarrhea in solid-organ transplant recipients: a review of the evidence

OBJECTIVE

To provide a comprehensive review of the literature as it relates to diarrhea in solid organ transplant (SOT) recipients. In this article, we review the epidemiology, pathogenesis, clinical manifestations, diagnosis and management of diarrhea in SOT recipients and discuss recent advances and challenges.

METHODS

Two investigators conducted independent literature searches using PubMed, Web of Science, and Scopus until January 1st, 2013. All databases were searched using a combination of the terms diarrhea, solid organ transplant, SOT, transplant associated diarrhea, and transplant recipients. Articles that discussed diarrhea in SOT recipients were reviewed and relevant cross-references also read and evaluated for inclusion. Selection bias could be a possible limitation of the approach used in selecting or finding articles for this article.

FINDINGS

Post-transplant diarrhea is a common and distressing occurrence in patients, which can have significant deleterious effects on the clinical course and well-being of the organ recipient. A majority of cases are due to infectious and drug-related etiologies. However, various other etiologies including inflammatory bowel disease must be considered in the differential diagnosis. A step-wise, informed approach to post-transplant diarrhea will help the clinician achieve the best diagnostic yield. The use of diagnostic endoscopy should be preceded by exclusion of an infectious or drug-related cause of diarrhea. Empiric management with antidiarrheal agents, probiotics, and lactose-free diets may have a role in managing patients for whom no cause can be determined even after an extensive investigation.

CONCLUSIONS

Physicians should be familiar with the common etiologies that result in post-transplant diarrhea. A directed approach to diagnosis and treatment will not only help to resolve the diarrhea but also prevent potentially life-threatening consequences including loss of the graft as well. Prospective studies are required to determine the etiology of post-transplant diarrhea in different clinical and geographic settings.

Genotypic and phenotypic analysis of diarrheagenic Escherichia coli strains isolated from Brazilian children living in low socioeconomic level communities

Background

Childhood diarrheal diseases remain highly endemic in developing areas of Brazil. The importance of Escherichia coli among children with diarrhea in these areas was unknown. This study determined the prevalence of different E. coli categories in symptomatic and asymptomatic children from low socioeconomic level rural communities in southeastern Brazil.

Methods

A total of 560 stool samples were collected from 141 children with diarrhea (< 10 years) and 419 apparently healthy controls who resided in 23 communities. E. coli isolates (n = 1943) were subjected to two multiplex PCRs developed for the detection of enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC), diffusely adherent E. coli (DAEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and Shiga toxin-producing E. coli (STEC). Strains were also examined for the presence of EPEC, EAEC, and DAEC by assays of adhesion to HEp-2 cells and by hybridization with specific DNA probes.

Results

Diarrheagenic E. coli strains were isolated from 253 (45.2%) children, and were associated with diarrhea in children aged < 5 years (p < 0.001). EAEC (20.9%), DAEC (11.6%), EPEC (9.3%) were the most frequent pathotypes, followed by ETEC (2.7%), EIEC (0.5%), and STEC (0.2%). Depending of the assay, EPEC, EAEC, and DAEC (collectively termed enteroadherent E. coli) strains were isolated in 45% to 56% of diarrhea cases, a significantly higher incidence than in controls (P < 0.05). Individually, only DAEC showed significant association with diarrhea (p < 0.05), particularly in children aged 2–5 years.

Conclusion

This study indicates that enteroadherent E. coli is an important cause of diarrhea in children living in low socioeconomic level communities in southeastern Brazil. Our results reveal that the PCR1 assay is an excellent tool for the identification of EAEC and DAEC.

Clostridium difficile infection in children: a comprehensive review

OBJECTIVE

To provide a comprehensive review of the literature relating to Clostridium difficile (C. difficile) infection (CDI) in the pediatric population.

METHODS

Two investigators conducted independent searches of PubMed, Web of Science, and Scopus until March 31st, 2013. All databases were searched using the terms 'Clostridium difficile infection', 'Clostridium difficile associated diarrhea' 'antibiotic associated diarrhea', 'C. difficile', in combination with 'pediatric' and 'paediatric'. Articles which discussed pediatric CDI were reviewed and relevant cross references also read and evaluated for inclusion. Selection bias could be a possible limitation of this approach.

FINDINGS

There is strong evidence for an increased incidence of pediatric CDI. Increasingly, the infection is being acquired from the community, often without a preceding history of antibiotic use. The severity of the disease has remained unchanged. Several medical conditions may be associated with the development of pediatric CDI. Infection prevention and control with antimicrobial stewardship are of paramount importance. It is important to consider the age of the child while testing for CDI. Traditional therapy with metronidazole or vancomycin remains the mainstay of treatment. Newer antibiotics such as fidaxomicin appear promising especially for the treatment of recurrent infection. Conservative surgical options may be a life-saving measure in severe or fulminant cases.

CONCLUSIONS

Pediatric providers should be cognizant of the increased incidence of CDI in children. Early and judicious testing coupled with the timely institution of therapy will help to secure better outcomes for this disease.

Sociocultural determinants of anticipated vaccine acceptance for acute watery diarrhea in early childhood in Katanga Province, Democratic Republic of Congo

Rotavirus and oral cholera vaccines have the potential to reduce diarrhea-related child mortality in low-income settings and are recommended by the World Health Organization. Uptake of vaccination depends on community support, and is based on local priorities. This study investigates local perceptions of acute watery diarrhea in childhood and anticipated vaccine acceptance in two sites in the Democratic Republic of Congo. In 2010, 360 randomly selected non-affected adults were interviewed by using a semi-structured questionnaire. Witchcraft and breastfeeding were perceived as potential cause of acute watery diarrhea by 51% and 48% of respondents. Despite misperceptions, anticipated vaccine acceptance at no cost was 99%. The strongest predictor of anticipated vaccine acceptance if costs were assumed was the educational level of the respondents. Results suggest that the introduction of vaccines is a local priority and local (mis)perceptions of illness do not compromise vaccine acceptability if the vaccine is affordable.

Relationship between Aedes aegypti production and occurrence of Escherichia coli in domestic water storage containers in rural and sub-urban villages in Thailand and Laos

In a cross-sectional survey in one rural and one suburban village each in Thailand and Laos the relationship between Aedes aegypti production and Escherichia coli contamination in household water storage containers was investigated. Entomological and microbiological surveys were conducted in 250 and 239 houses in Thailand and Laos, respectively. Entomological indices across all four villages were high, indicating a high risk for dengue transmission. Significantly more Ae. aegypti pupae were produced in containers contaminated with E. coli as compared to those that were not, with the odds of Ae. aegypti infested containers being contaminated with E. coli ranging from two to five. The level of E. coli contamination varied across container classes but contamination levels were not significantly associated with the number of pupae produced. We conclude that the observed relationship between Ae. aegypti production and presence of E. coli in household water storage containers suggests a causal relationship between dengue and diarrheal disease at these sites. How this relationship can be exploited for the combined and cost-effective control of dengue and diarrheal diseases requires further research.

Prevalence of rotavirus and adenovirus associated with diarrhea among displaced communities in Khartoum, Sudan

BACKGROUND

Diarrheal diseases represent a major worldwide public health problem particularly in developing countries. Each year, at least four million children under five years of age die from diarrhea. Rotavirus, enteric adenovirus and some bacterial species are the most common identified infectious agents responsible for diarrhea in young children worldwide. This study was conducted to determine prevalence of rotavirus and adenovirus associated with diarrhea among displaced communities in Khartoum state, Sudan.

METHODS

A total of seven hundred and ten patients, children and adults, suffering from diarrhea were examined. The clinical history, socio-demographic characteristics, physical examination findings and laboratory investigations were recorded. Stool samples or rectal swabs were collected and tested for rotavirus and adenovirus antigens using the immuno-chromatography test (ICT). Characterization of the identified Rotaviruses, as a major cause of diarrhea, was then made using real time-reverse transcription PCR. To make the study legal, an ethical clearance was obtained from Sudan Ministry of health- Research Ethical Committee. Written consent was taken from adult subjects, and also from children mothers.The participants were informed using simple language about the infection, aim of the research and the benefits of the study.

RESULTS

Out of the 710 patients, viral pathogens were detected in only 99 cases (13.9%). Of the 99 cases of viral diarrhea, 83 (83.8%) were due to rotaviruses while 16 (16.2%) attributed to adenovirus. Of the 83 rotaviruses identified, 42 were characterized by RT-PCR, of these 40 (95.2%) were proved as type A (VP6), and 2 (4.8%) type C (VP7). Type C (VP7) rotavirus was detected in samples collected from children under 5 years only.

CONCLUSIONS

In conclusion, most cases of viral diarrhea are found to be caused by rotavirus especially among children less than five years. Most of the identified rotavirus belonged to type A (VP6).It was also evident that most patients are those who drank untreated water obtained from donkey carts source and who had no access to latrines, and lived in poor environmental conditions would acquire diarrheal infection.

Enhanced membrane-tethered mucin 3 (MUC3) expression by a tetrameric branched peptide with a conserved TFLK motif inhibits bacteria adherence

We investigated whether a synthetic tetrameric branched peptide based on the conserved TFLK motif from mammary-associated serum amyloid A3 (M-SAA3) is more efficient than the monomeric peptide at up-regulating MUC3 expression and examined the possible mechanism(s) and biological significance of this process. We used standard solid-phase methods to synthesize a tetrameric branched peptide (sequence GWLTFLKAAG) containing a trilysine core, termed the TFLK-containing 10-mer BP. The aberrant expression of transcription factors was analyzed using a transcription factor protein/DNA array. MUC3 and relevant transcription factors were detected using real-time PCR and/or Western blots. The luciferase assay, EMSA, and ChIP assays were used to analyze the activity of the human MUC3 promoter. The bacterial adherence assay was used to evaluate the in vitro inhibition of enteropathogenic Escherichia coli or enterohemorrhage E. coli serotype O157:H7 (EHEC O157:H7) adherence to HT-29-Gal cells after treatment with the TFLK-containing 10-mer BP. In HT-29-Gal cells, the TFLK-containing 10-mer BP induced higher levels of MUC3 expression than the M-SAA3-derived N-terminal 10-mer monomeric peptide, and MUC3 expression was activated through transcriptional mechanisms, including the induction of multiple transcription factors and further binding with their cis-elements between nucleotides -242 and -62 within MUC3 promoter. Interestingly, the TFLK-containing 10-mer BP dramatically inhibited enteropathogenic E. coli and EHEC O157:H7 adherence to the HT-29-Gal cells compared with the controls. This finding suggests a potential therapeutic use for this peptide to prevent gastrointestinal infection.

Surveillance for enteric pathogens in a case-control study of acute diarrhea in Western Kenya

BACKGROUND

Acute diarrhea remains a major public health problem in East African nations such as Kenya. Surveillance for a broad range of enteric pathogens is necessary to accurately predict the frequency of pathogens and potential changes in antibiotic resistance patterns.

METHOD

Stool samples were collected from September 2009 to September 2011; 193 and 239 samples, from age-matched cases and asymptomatic controls, were collected, respectively, from Kericho and Kisumu District Hospitals in western Kenya. Bacterial pathogens were identified by conventional microbiological methods; antibiotic susceptibility of bacterial isolates was ascertained using the MicroScan WalkAway 40 Plus. An enzyme immunoassay kit was used to detect rotavirus, and ova and parasite examination was conducted by microscopy and an enzyme immunoassay.

RESULTS

Rotavirus (10.2% and 10.5%) and Shigella (11% and 8%) were isolated significantly more often in the cases than the controls from Kericho and Kisumu District Hospitals respectively. The diarrheagenic Escherichia coli, Campylobacter jejuni and Salmonella were found most often in the cases while Giardia lamblia and Entamoeba histolytica/E. dispar were found more often in the controls. Most pathogens were isolated from children under 5 years old. More than 50% of the Shigella, Salmonella and diarrheagenic E. coli isolates were multidrug resistant to ampicillin, tetracycline and trimethoprim/sulfamethoxazole with several enteroaggregative and enterotoxigenic E. coli isolates producing extended-spectrum beta-lactamases.

CONCLUSION

Accurate epidemiologic information on acute diarrheal illness in Kenya will be critical for augmenting existing diarrhea management policies in terms of treatment and to strengthen future community awareness and health promotion programs.

Immune responses and protection in children in developing countries induced by oral vaccines

Oral mucosal vaccines have great promise for generating protective immunity against intestinal infections for the benefit of large numbers of people especially young children. There however appears to be a caveat since these vaccines have to overcome the inbuilt resistance of mucosal surfaces and secretions to inhibit antigen stimulation and responses. Unfortunately, these vaccines are not equally immunogenic nor protective in different populations. When compared to industrialized countries, children living in developing countries appear to have lower responses, but the reasons for these lowered responses are not clearly defined. The most likely explanations relate to undernutrition, micronutrient deficiencies, microbial overload on mucosal surfaces, alteration of microbiome and microbolom and irreversible changes on the mucosa as well as maternal antibodies in serum or breast milk may alter the mucosal pathology and lower immune responses to interventions using oral vaccines. The detrimental effect of adverse environment and malnutrition may bring about irreversible changes in the mucosa of children especially in the first 1000 days of life from conception to after birth and up to two years of age. This review aims to summarize the information available on lowered immune responses to mucosal vaccines and on interventions that may help address the constraints of these vaccines when they are used for children living under the greatest stress and under harmful adverse circumstances.

[Epidemiology of rotavirus gastroenteritis among children under 5 years of age in Tunisia - results of sentinel hospital surveillance 2009 to 2011]

BACKGROUND

Rotavirus is the major cause of severe acute gastroenteritis among young children. The objectives of this study were to assess the epidemiology, clinical and virological features of community-acquired rotavirus acute gastroenteritis, in children under 5 years of age, hospitalized in Tunisia.

METHODS

A multicenter prospective observational study was conducted from April 2009 to March 2011, in 11 sentinel pediatric departments. Clinical data and stool samples were collected for all children under 5 years, admitted for acute gastroenteritis. Rotavirus was detected by Elisa immunoassay test and genotyped for G and P by semi-nested multiplex RT-PCR.

RESULT

A total of 621 children were enrolled in this study. Rotavirus was detected in 30.3% of cases (95% CI [26.7-33.9]). The estimated incidence rate of rotavirus acute gastroenteritis was 11 cases/100,000 child-years (95% CI [9.43-12.57]). This infection affected predominantly children aged under 24 months, and occurred mainly in winter (55.3%). Vomiting, fever and dehydration were observed in 79.6%, 69.5% and 57% respectively. Genotype analysis identified four G types (G1, G2, G3 and G4) and 4 P types (P[4], P[6], P[8] and P[9]). The most common G/P combination was G3P[8] (24.4%), followed by G4P[8] (13.3%) and G1P[8] (6.5%).

CONCLUSION

These results highlight the frequency and potential severity of rotavirus acute gastroenteritis in pediatric hospital settings. The present study could provide a sufficient database to make a decision related to the introduction of rotavirus vaccine in Tunisian national immunization program.

Incidence of diarrhoeagenic Escherichia coli isolated from young children with diarrhoea in the west of Iran

Diarrhoeagenic Escherichia coli (DEC) represents a main group of enteric pathogens that cause human diarrhoea. Because it is not simply distinguished from normal flora by simple laboratory methods, modern molecular diagnostic assays are necessary. Although it is neither necessary nor applicable to perform PCR for all patients, it is of many advantages to verify the prevalence of DEC in different areas by this method. Knowing the prevalence of DEC in an area, we can focus on few pathogens and narrow our antimicrobial treatment. The aim of this study is to evaluate the contribution of the different DEC categories in children diarrhoea in the west of Iran.The stool specimens of 251 children with diarrhoea were collected from June to September 2007. Polymerase chain reaction (PCR) was performed to determine the presence of enteropathogenic (EPEC), enterotoxigenic (ETEC), entero-invasive (EIEC), Shiga toxin-producing (STEC) and entero-aggregative (EAEC) strains. ETEC strains were isolated from 13 and EAEC strains from 16 children. STEC was detected in 7 children, and no EIEC was isolated. Finally, EPEC strains were isolated in 41 cases. EAEC and EPEC are the most frequent DECs in children less than 10 years of age in West of Iran.

Role of binding and nucleoside diphosphate kinase A in the regulation of the cystic fibrosis transmembrane conductance regulator by AMP-activated protein kinase

Cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel mutations cause cystic fibrosis lung disease. A better understanding of CFTR regulatory mechanisms could suggest new therapeutic strategies. AMP-activated protein kinase (AMPK) binds to and phosphorylates CFTR, attenuating PKA-activated CFTR gating. However, the requirement for AMPK binding to CFTR and the potential role of other proteins in this regulation are unclear. We report that nucleoside diphosphate kinase A (NDPK-A) interacts with both AMPK and CFTR in overlay blots of airway epithelial cell lysates. Binding studies in Xenopus oocytes and transfected HEK-293 cells revealed that a CFTR peptide fragment that binds AMPK (CFTR-1420-57) disrupted the AMPK-CFTR interaction. Introduction of CFTR-1420-57 into human bronchial Calu-3 cells enhanced forskolin-stimulated whole cell conductance in patch clamp measurements. Similarly, injection of CFTR-1420-57 into Xenopus oocytes blocked the inhibition of cAMP-stimulated CFTR conductance by AMPK in two-electrode voltage clamp studies. AMPK also inhibited CFTR conductance with co-expression of WT NDPK-A in two-electrode voltage clamp studies, but co-expression of a catalytically inactive H118F mutant or various Ser-120 NDPK-A mutants prevented this inhibition. In vitro phosphorylation of WT NDPK-A was enhanced by purified active AMPK, but phosphorylation was prevented in H118F and phosphomimic Ser-120 NDPK-A mutants. AMPK does not appear to phosphorylate NDPK-A directly but rather promotes an NDPK-A autophosphorylation event that involves His-118 and Ser-120. Taken together, these results suggest that NDPK-A exists in a functional cellular complex with AMPK and CFTR in airway epithelia, and NDPK-A catalytic function is required for the AMPK-dependent regulation of CFTR.

Comparison of the Triage Micro Parasite Panel and Microscopy for the Detection of Entamoeba histolytica/Entamoeba dispar, Giardia lamblia, and Cryptosporidium parvum in Stool Samples Collected in Kenya

Entamoeba histolytica, Giardia lamblia, and Cryptosporidium parvum are three of the most important parasitic causes of acute diarrhea worldwide. Laboratory diagnosis of these parasites is usually done by ova and parasite examination (O&P examination) via microscopy. The sensitivity and specificity of O&P examination varies among laboratories and can be labor intensive and time consuming. The Triage Micro Parasite Panel (BioSite, San Diego, California) is an enzyme immunoassay kit that can detect E. histolytica/E. dispar, G. lamblia, and C. parvum simultaneously using fresh or frozen stool. The present study evaluated the Triage Micro Parasite Panel in detecting E. histolytica/E. dispar, G. lamblia, and C. parvum compared to O&P examination in 266 stool samples collected at medical facilities in Kenya. The sensitivity and specificity results for the Triage Micro Parasite Panel were: for E. histolytica/E. dispar: 100%, 100%, G. lamblia: 100%, 100% and C. parvum: 73%, 100%. There was no evidence of cross reactivity using the kit with other parasites identified in the stool specimens. These results indicate that the Triage Micro Parasite Panel is a highly sensitive kit that can be used for screening purposes in large scale studies or outbreak investigations or as a possible alternative to O&P examination.

Etiology of acute diarrhea due to enteropathogenic bacteria in Beijing, China

OBJECTIVES

Acute diarrhea is of great concern due to considerable morbidity and mortality worldwide. The causative bacteria leading to acute diarrhea in general population remains unclear in China. This study was conducted to determine the etiology of acute diarrhea using a sentinel hospital-based surveillance network in Beijing.

METHODS

Active surveillance was implemented from April 2010 to December 2011 on two random days per week by enrolling every tenth diarrheal patients admitted to seventeen intestinal clinics. Shigella spp., Vibrio spp, Salmonella spp., diarrheagenic Escherichia coli and other genera of bacteria, were investigated from 4803 outpatients with acute diarrhea by microbiological methods.

RESULTS

The pathogenic bacteria recovered out from fecal samples of 968 (20.2%) patients had the following profile: Shigella spp. (5.9%) was the most prevalent pathogen, Vibrio parahaemolyticus (5.2%), Salmonella spp. (3.9%) and enteropathogenic E. coli (EPEC) (0.9%) had from the second to fourth highest prevalence, respectively. Of the 55 co-infections detected, V. parahaemolyticus was the most common pathogen from 28 cases (50.9%), with the main combination of V. parahaemolyticus and Salmonella. The highest proportion of all causative bacteria was found in adults aged 20-39 year and in summer as well as early autumn. The clinical symptoms associated with specific bacterial infection, such as fever, abdominal pain, tenesmus, nausea, vomiting, and watery and bloody stool, were observed frequently in diarrheal patients.

CONCLUSION

Shigella spp., V. parahaemolyticus, Salmonella spp., and EPEC are important enteropathogenic bacteria causing acute diarrhea in Beijing. To execute reasonable interventions, the comprehensive and continuous surveillance is needed to identify the prevalence of different enteropathogeic bacteria.

Novel in vitro and in vivo models and potential new therapeutics to break the vicious cycle of Cryptosporidium infection and malnutrition

BACKGROUND

Although several animal models of cryptosporidiosis have been reported, most involve genetically or pharmacologically immune-suppressed hosts.

METHODS

We report challenge with excysted (in vitro and in vivo) and unexcysted (in vivo) Cryptosporidium parvum oocysts in human colonic adenocarcinoma (HCT-8) cells and weaned nourished and malnourished C57BL/6 mice, following outcomes of growth rate, stool shedding, and tissue burden. We tested treatment with an oligodeoxynucleotide containing unmethylated CpG motif (CpG-ODN) and alanyl-glutamine in vivo and in vitro.

RESULTS

C. parvum-challenged mice showed prolonged weight loss (>10% over 4 days), robust stool shedding (>3 logs/d over 7 days), and epithelial infection in the ileum, cecum, and colon. Of 2 potential therapeutic compounds evaluated in the model, CpG-ODN reduced body weight loss (to <6% on days 3-7 after challenge), reduced shedding of organisms (by 25% on days 1 and 3 after challenge), and decreased the burden of parasites in the ileum. Alanyl-glutamine showed similar benefits. In vitro findings suggested that effects on the epithelial component of the mucosa probably likely responsible for beneficial effects seen in vivo.

CONCLUSIONS

Weaned mice provide a convenient and reproducible model of cryptosporidial disease, including its vicious cycle with body weight loss and heavier infection with malnutrition, and this model may be useful in exploring innovative therapeutic solutions for this challenging infectious disease.

Concentração de sódio e glicose em soro de reidratação oral preparado por Agentes Comunitários de Saúde

A diarreia infantil é importante causa de morbimortalidade, sendo indicativo para terapia de reidratação oral (TRO). Este estudo objetivou avaliar o teor de sódio e glicose em soro de reidratação oral preparado por Agentes Comunitários de Saúde (ACS) que atuam em Unidades Básicas de Saúde (UBS), caracterizando o perfil e o conhecimento destes sobre a TRO. Após responderem questionário com informações profissionais e sobre a TRO, os ACS a prepararam por três métodos. O teor de glicose e de sódio das TRO foi determinado e comparado ao proposto pela OMS. Na análise estatística foram utilizados ANOVA, Tukey e odds ratio. Participaram do estudo 52 ACS, majoritariamente mulheres e com ensino médio completo (90,4%). A adequação da TRO foi de 3,9; 9,8 e 28,9% para a colher caseira, colher medida e punhado pitada, respectivamente. O preparo da TRO com a colher caseira resultou em 88,0% das amostras com teor de sódio perigoso à saúde (>101 mmol/L). Entre os ACS, 38,5% tinham menos de 2 anos de trabalho, com risco 4,8 vezes maior de preparar TRO inadequada em sódio. Os ACS referiram indicar a TRO no tratamento da diarreia infantil, desconhecendo efeitos colaterais do preparo inadequado. A composição da TRO produzida pelos ACS foi inadequada em todos os métodos. É recomendável treinamento dos ACS no preparo da TRO.

Clinical approach to severe Clostridium difficile infection: update for the hospital practitioner

The rising incidence of Clostridium difficile (C. difficile) infection or CDI is now a problem of pandemic proportions. The NAP1 hypervirulent strain of C. difficile is responsible for a majority of recent epidemics and the widespread use of fluoroquinolone antibiotics may have facilitated the selective proliferation of this strain. The NAP1 strain also is more likely to cause severe and fulminant colitis characterized by marked leukocytosis, renal failure, hemodynamic instability, and toxic megacolon. No single test suffices to diagnose severe CDI, instead; the clinician must rely on a combination of clinical acumen, laboratory testing, and radiologic and endoscopic modalities. Although oral vancomycin and metronidazole are considered standard therapies in the medical management of CDI, recently it has been demonstrated that vancomycin is the more effective antibiotic in cases of severe disease. Moreover, early surgical consultation is necessary in patients who do not respond to medical therapy or who demonstrate rising white blood cell counts or hemodynamic instability indicative of fulminant colitis. Subtotal colectomy with end ileostomy is the procedure of choice for fulminant colitis. When applied to select patients in a judicious and timely fashion, surgery can be a life-saving intervention. In addition to these therapeutic approaches, several investigational treatments including novel antibiotics, fecal bacteriotherapy and immunotherapy have shown promise in the care of patients with severe CDI.

Bacterial enteropathogens associated with diarrhea in a rural population of Haiti

Purpose

Diarrheal disease is one of the leading causes of morbidity in developing countries. To further understand the epidemiology of diarrheal disease among a rural population surrounding Robillard, Haiti, fecal swabs from patients with diarrhea were screened for the presence of enteropathogenic bacteria.

Patients and methods

Fecal swabs were collected from 34 patients with signs and symptoms of diarrhea and stored in BBL™ Cary-Blair transport medium (Becton, Dickinson and Company, Sparks, MD) until transit to the USA. Swab material was inoculated on to different enrichment and selective agars for incubation. Fermenting and nonfermenting bacteria that grew on the enteric selection media were identified by the BBL™ Crystal™ Enteric/Nonferementing Identification system (Becton, Dickinson and Company). Organisms identified as Escherichia coli were further screened for the presence of virulence factors by polymerase chain reaction (PCR).

Results

Of 34 patients, no Campylobacter, Shigella, Salmonella, or Vibrio spp. were isolated from swabs transported to the USA for culture. Of 73 E. coli isolates cultured from the swabs, one enteropathogenic strain of E. coli was identified by multiplex PCR. Escherichia fergusonii and Cronobacter sakazakii, both potential gastrointestinal pathogens, were also isolated from patient stools.

Conclusion

This study was undertaken to determine if bacterial enteropathogens could be detected in the stools of patients suffering from diarrhea or dysentery and, in the absence of sufficient facilities, rectal swabs could be transported to the USA for culture. Although several genera of overt enteropathogens were not detected, one enteropathogenic E. coli and other pathogenic enterobacteriaceae were successfully cultured and identified.

A gastroenteritis outbreak caused by noroviruses in Greece

In June 2006, an outbreak alert regarding cases of acute gastroenteritis in a region in North Eastern Greece (population 100,882 inhabitants), triggered investigations to guide control measures. The outbreak started the first days of June, and peaked in July. A descriptive epidemiological study, a virological characterization of the viral agent identified from cases as well as a phylogenetic analysis was performed. From June 5 to September 3, 2006 (weeks 23–44), 1,640 cases of gastroenteritis (45.2% male and 54.8% female, aged 3 months to 89 years) were reported. The overall attack rate for the period was 16.3 cases/1,000 inhabitants. About 57% of cases observed were under the age of 15 years. nalysis of faecal samples identified Norovirus GII strains. Fifteen different Norovirus GII strains were recorded, presenting a homology of 94.8% (86–97%) to GII strains obtained from GenBank. The long duration of the outbreak suggests an important role of person-to-person transmission, while the emergence of the outbreak was possibly due to contaminated potable water, although no viruses were detected in any tested water samples. This outbreak underscores the need for a national surveillance system for acute non-bacterial gastroenteritis outbreaks.

Real-time multiplex PCR for simultaneous detection of Campylobacter jejuni, Salmonella, Shigella and Yersinia species in fecal samples

Diarrheal diseases due to notifiable bacterial infections require rapid diagnosis of the causative pathogens. To facilitate detection, a real-time multiplex PCR was developed that identifies common diarrhea-causing bacteria in fecal samples. On the basis of published sequence data, sets of primers and probes were designed that were specific for Campylobacter jejuni, Salmonella, Shigella/enteroinvasive Escherichia coli EIEC, and Yersinia species, suitable for use in a one-tube PCR assay. The assay was assessed using a list of 137 well-defined intestinal bacterial strains or isolates. Furthermore, 393 routine clinical stool samples were analyzed, and the results of real-time multiplex PCR were compared with those obtained by established microbiological methods. The PCR yielded results within 3h including DNA purification. No false-positive signals or cross-reactions were observed. The analytical sensitivity was 10(3)cfumL(-1) for Campylobacter jejuni, 10(4)cfumL(-1) for Salmonella, and 10(5)cfumL(-1) for Shigella/EIEC and Yersinia, respectively. Compared with culture, PCR detected 79 out of 81 Campylobacter jejuni (97.5%), 71 out of 74 Salmonella (96%), 8 out of 8 Shigella (100%), and 10 out of 10 Yersinia-positive (100%) clinical samples. In culture-negative samples (n=192), PCR additionally detected 2 Shigella, 1 Salmonella, and 5 Campylobacter jejuni infections. Thus, the new real-time multiplex PCR provides reliable results within a short time and might be useful as an additional diagnostic tool whenever time is important in the diagnosis of enteropathogenic bacteria.

Efficacy of diosmectite (smecta) in the treatment of acute watery diarrhoea in adults: a multicentre, randomized, double-blind, placebo-controlled, parallel group study

Background. Although diosmectite has demonstrated efficacy in the treatment of acute watery diarrhoea in children, its efficacy in adults still needs to be assessed. The objective of this study was therefore to assess the efficacy of diosmectite on the time to recovery in adults with acute diarrhoea. Methods. A total of 346 adults with at least three watery stools per day over a period of less than 48 hours were prospectively randomized to diosmectite (6 g tid) or placebo during four days. The primary endpoint was time to diarrhoea recovery. Results. In the intention-to-treat population, median time to recovery was 53.8 hours (range [3.7–167.3]) with diosmectite (n = 166) versus 69.0 hours [2.2–165.2] with placebo, (n = 163; P = .029), which corresponds to a difference of 15.2 hours. Diosmectite was well tolerated. Conclusion. Diosmectite at 6 g tid was well tolerated and reduced the time to recovery of acute watery diarrhoea episode in a clinically relevant manner.

Molecular basis of virulence in clinical isolates of Escherichia coli and Salmonella species from a tertiary hospital in the Eastern Cape, South Africa

BACKGROUND

Apart from localized gastrointestinal infections, Escherichia coli and Salmonella species are major causes of systemic disease in both humans and animals. Salmonella spp. cause invasive infections such as enteric fever, septicemia, osteomyelitis and meningitis while certain types of E. coli can cause systemic infections, includingpyelonephritis, meningitis and septicemia. These characteristic requires the involvement of a myriad of virulence factors.

METHODS

This study investigated the virulence factors of Escherichia coli and Salmonella species in clinical specimens from patients with diarrhoea presenting to health care centres in Oliver R. Tambo District Municipality, Eastern Cape Province, Republic of South Africa. Microbiology analysis involved the use of cultural and molecular techniques.

RESULTS

Out of a total of 315 samples screened, Salmonella isolates were obtained in 119 (37.8%) of cases and these comprised: S. choleraesuis (6%), S. enteritidis (4%), S. eppendorf (1%), S. hadar (1%), S. isangi (8%), S. panama (1%), S. typhi (52%), S. typhimurium (25%) and untyped Salmonella spp. (2%). Among the Salmonella species 87 (73.1%) were invasive. Using molecular diagnostic methods, diarrheagenic E. coli were detected in 90 cases (28.6%): the greater proportion of this were enteroaggregative E. coli (EAEC) 37 (41.1%), enteropathogenic E. coli (EPEC) 21 (23.3%) and enterohemorrhagic E. coli (EHEC) 21 (23.3%). The predominant virulence gene among the diarrheagenic E. coli was EAEC heat-stable enterotoxin astA genes while the virulence genes identified in the Salmonella strains were 15 (12.6%) flic and 105 (88.2%) inv genes. The amino acid identity of the representative genes showed 95-100% similarity to corresponding blast searched sequence.

CONCLUSIONS

This study showed the diversity of virulence gene expression in two major enteric pathogens. S. typhi and enteroaggregative E. coli were the predominant enteropathogens in our study area with an indication that EAEC is endemic within our study population. It was observed among other things that some diarrheagenic E. coli isolated from apparently asymptomatic subjects expressed some virulence genes at frequency as high as seen in diarrheagenic cases. This study underlines the importance of understanding the virulence composition and diversity of pathogens for enhanced clinico-epidemiological monitoring and health care delivery.

Enteric protozoan parasites in rural areas of bandar-abbas, southern iran: comparison of past and present situation

BACKGROUND

The main goal was to address the prevalence of enteric protozoan parasites in rural areas of Bandar-Abbas, southern Iran and to compare the results with the only conducted study in 1978.

METHODS

This descriptive study was performed from 2009 through 2010 on the 565 fecal samples. Formalin-ether concentration technique was performed and the analysis was carried out using Chi-square test in SPSS software version 13.5. Finally, the comparison of our results with the only previous study which was accomplished by Sheiban and Rezaeian in 1978 was done.

RESULTS

The overall prevalence of the protozoan parasites was 48.8%. However, the prevalence of pathogen parasites was 23%. Previous research in 1978 showed 80.4% infectivity. The most protozoan parasites were Blastocystis hominis (25.53%), Giardia lamblia (17.2%) and Entamoeba coli (15.95%). Previous study in 1978 found Entamoeba coli as the most common protozoa. Our finding revealed that the rate of single infectivity was much higher compared to previous research. The most frequency of infection was in children.

CONCLUSION

The remarkable decrease of protozoan parasites is mainly due to progress in health care in the villages; however more effort should be done with the goal of eradicating infectious agents.