Multiplex polymerase chain reaction tests for detection of pathogens associated with gastroenteritis

A wide range of enteric pathogens can cause infectious gastroenteritis. Conventional diagnostic algorithms are time-consuming and often lack sensitivity and specificity. Advances in molecular technology have provided new clinical diagnostic tools. Multiplex polymerase chain reaction (PCR)-based testing has been used in gastroenterology diagnostics in recent years. This article presents a review of recent laboratory-developed multiplex PCR tests and current commercial multiplex gastrointestinal pathogen tests. It focuses on two commercial syndromic multiplex tests: Luminex xTAG Gastrointestinal Pathogen Panel and BioFire FilmArray gastrointestinal test. Multiplex PCR tests have shown superior sensitivity to conventional methods for detection of most pathogens.

Parasitic gastroenteritis in lambs widespread

Parasitic gastroenteritis diagnosed in lambs by all veterinary investigation centres, Clostridium perfringens epsilon enterotoxaemia suspected in two cows, Comparative quarterly porcine reproductive and respiratory syndrome diagnoses reach a 10-year peak, Failure of an entire colony of gulls in Cumbria, Endoparasitism the predominant feature in exotic farmed animals, These are among matters discussed in the Animal and Plant Health Agency's (APHA's) disease surveillance report for September 2014.

Multilevel analysis of childhood nonviral gastroenteritis associated with environmental risk factors in Quebec, 1999-2006

Childhood nonviral gastroenteritis is a priority for various public health authorities. Given that waterborne transmission is sometimes incriminated during investigation of gastroenteritis outbreaks, the authors hypothesized that watershed characteristics may influence the occurrence of this disease and could contribute additional insights for better prevention and control. The study described here aimed to investigate watershed characteristics in relation to nonviral gastroenteritis and specifically three bacterial and parasitic forms of childhood gastroenteritis to assess their relative importance in the province of Quebec, Canada. Information on children aged 0-4 years with bacterial or parasitic enteric infections reported through ongoing surveillance between 1999 and 2006 in the province of Quebec was collected. Factors measured at the municipal and watershed levels were analyzed using multilevel models with a Poisson distribution and log link function. Childhood nonviral gastroenteritis, giardiasis, and campylobacteriosis were positively associated with small ruminants and cattle density. Childhood salmonellosis was positively associated with cattle density. Also, childhood campylobacteriosis incidence was positively associated with larger watershed agricultural surface. In addition to local agroenvironmental factors, this analysis revealed an important watershed effect.

[Changes in the heart of neonatal rats after cryptosporidial gastroenteritis of different degrees of severity]

Disturbances at the childhood age increase risk of the appearance of cardiovascular diseases decades later. The nature of this interconnection called ontogenetic programming is not completely understood. Valuable sources of knowledge about mechanisms of ontogenetic programming are data of interspecies study of biology of the body life cycles and of heart physiological capabilities. Taken into account the interspecies differences, these data allow finding the correct direction of experimental investigations. Results of studies of almost 100 homoiothermal species have shown the slow growth and a high loading on the heart at postnatal development to decrease its aerobic capability in adults. Basing on these data, we suggested that the neonatal gastroenteritis causing tachyarrhythmia, malabsorption, and the growth deceleration might lead to pathological changes in the heart. Our task was to evaluate the effect of cryptosporidial gastroenteritis of different degrees of severity on heart of the neonatal rats. By using methods of Real-Time PCR, immunocytochemistry, image analysis, and study of interatrial septum, we have established that a gradual increase of intensity of infestation with Cryptosporidium parvum oocytes causes sharp changes corresponding to the "all or nothing" response. At a weak infestation the interatrial septum was close (like in control), while significant changes in expression of isoforms of heavy chains of alpha- and beta-myosin were absent. At the intermediate and severe infestation, in the interatrial septum the foramen ovale was visualized and there were observed cardiac atrophy and a strong shift of ration of expression of myosin heavy chains toward the low-velocity beta chain. Thus, by disturbing the frequency-strength ratios and causing outflow of resources from the formed heart, the neonatal gastroenteritis produces pathological changes of the organ molecular and anatomical structures. Our results can be interest to evolutionary biologists and physicians, as they show importance of knowledge of evolutionary-comparative investigations for the search for novel risk factors of heart diseases and demonstrate interconnection between gastroenteritis, pathology of interatrial septum, and a change of composition of the main contractile proteins in cardiomyocytes.

Community incidence of pathogen-specific gastroenteritis: reconstructing the surveillance pyramid for seven pathogens in seven European Union member states

By building reconstruction models for a case of gastroenteritis in the general population moving through different steps of the surveillance pyramid we estimated that millions of illnesses occur annually in the European population, leading to thousands of hospitalizations. We used data on the healthcare system in seven European Union member states in relation to pathogen characteristics that influence healthcare seeking. Data on healthcare usage were obtained by harmonized cross-sectional surveys. The degree of under-diagnosis and underreporting varied by pathogen and country. Overall, underreporting and under-diagnosis were estimated to be lowest for Germany and Sweden, followed by Denmark, The Netherlands, UK, Italy and Poland. Across all countries, the incidence rate was highest for Campylobacter spp. and Salmonella spp. Incidence estimates resulting from the pyramid reconstruction approach are adjusted for biases due to different surveillance systems and are therefore a better basis for international comparisons than reported data.

Prevalence and characters of Entamoeba histolytica infection in Saudi infants and children admitted with diarrhea at 2 main hospitals at South Jeddah: a re-emerging serious infection with unusual presentation

In this study, Entamoeba histolytica had high prevalence and unusual presentation by affecting high proportion of infants under 1 year; severe clinical manifestations, and laboratory findings that were known to be usually encountered in invasive amebiasis as significant leukocytosis for age, neutrophilic leukocytosis for age, and positive C-reactive protein were found among more than 50% of admitted Saudi infants and children with E. histolytica infection in our locality. E. histolytica can be a re-emerging serious infection when it finds favorable environmental conditions and host factors which are mainly attributed to inadequate breastfeeding in this study. This may occur in any other area of the world with the same risk factors, so we must be ready to tackle it with effective and more powerful preventive measures.

[High perinatal mortality associated with triple anthelmintic resistance in a German sheep flock]

High perinatal mortality, low milk yields and occasional ewe deaths were investigated in a Dorper sheep flock in Southern Germany. Parasitic gastroenteritis due to Trichostrongylus spp. associated with severe weight loss despite regular anthelmintic treatments of the flock was identified as the underlying cause. A faecal egg count reduction (FECR) test revealed zero reduction after treatment with ivermectin or albendazole, respectively, and a FECR of 57.9% following treatment with levamisole. These results indicate a lack of, or considerably reduced efficacy of substances from all three classical groups of anthelmintics and demonstrate that triple anthelmintic resistance is also present in Germany. The introduction of resistant worm populations with imported livestock, excessive use of anthelmintic drugs and under-dosing of goats have possibly led to the problem in the flock described. Veterinary advice on anthelmintic treatments and responsible parasite control programmes are therefore crucial in small ruminant flocks.

[Etiological aspects of acute gastroenteritis--a ten-year review (1.01. 2001-31.12.2010)]

Acute gastroentritis is one of the most common diseases in humans, and continues to be a significant cause of morbidity worldwide.

AIMS

To determine the bacterial pathogens associated with gastroenteritis in patients admitted to the Iasi Infectious Diseases Hospital in the last ten years.

MATERIAL AND METHODS

A total of 40481 stool samples were examined using conventional methods.

RESULTS

Bacteria were found in 7.36% of cases, and parasites in 9.64%; 83% of the cases were viral, micotic, or disbiotic. The bacterial etiology was dominated by Salmonella spp. (58.34%), Shigella spp. (27.08%), Yersinia enterocolitica 03 (8.53%), Campylobacter spp. (1.31%), other bacterial pathogens (EPEC, Aeromonas hydrophilla/caviae/sobria, Plesiomonas shigelloides, Bacillus cereus, Staphylococcus aureus, etc) being detected in 3.74% of the cases. Of the Salmonella species, group B (51.99%) followed by group D (45.23%) were most common. Shigella sonnei and Shigella flexneri were found in almost the same proportion (49.45% and 49.70%, respectively); Shigella boydii was isolated in only 0.85% of cases. The trend of gastroenteritis caused by bacterial pathogens is decreasing: from 355 cases in 2001 to 105 cases in 2010; three peaks have been recorded in 2002, 2005 (when Salmonella typhi was isolated in a patient), and 2008 (469, 409, and 252 cases, respectively). Bacterial gastroenteritis affected both sexes almost equally (122 males and 118 females). The most affected age groups were: 0 - 4 years, 15 - 24 years, 5 - 14 years and 25 - 39 years.

CONCLUSIONS

Laboratory investigations are essential in determining the etiology of gastroenteritis. Its unpredictable incidence justifies the human and material efforts aimed at controlling the spread of potentially epidemic acute gastroenteritis.

[Cardiomyocyte myosin heavy chain composition change after cryptosporidial gastroenteritis]

Cardiovascular diseases are the most common case of human death in developed countries. Thus, the discovering of their new risk factors is of primary importance. Based on epidemiology studies, vertebrate life-history traits comparison and cross-species cardiomyocyte transcriptome analysis, we suggest that one of these factors could be infectious gastroenteritis. This disease outflows recourses from cardio-vascular system and triggers pathological stimuli, like tachyarrhythmia, inflammation, malapsorption and energy depletion thereby disturbing cardiomyocyte metabolism and function. To test this hypothesis, we challenged gastroenteritis in neonatal rats with widespread human parasite Cryptosporidium parvum (Apicomplexa, Sporozoa). The results obtained by the methods of immunocytochemistry, quantitative morphometry and real-time PCR, indicate that moderate cryptosporidiosis lasting four days induces dramatic shift in myosin isoform expression ration toward isoform beta (with low ATPase activity) both at mRNA (by 1.7-4.5 folds) and protein (by 2.5-6 folds) levels. Antithetical manner of this shift and coherence between changes in mRNA and protein suggest that cryptosporidiosis affects all main steps of a complex myosin heavy chain regulatory network. Since the overexpression of myosin heavy chain beta (showing several times lower ATPase activity than myosin heavy chain alfa) is a generally accepted marker of human cardiac failure, we can consider cryptosporidial gastroenteritis as a new risk factor of cardiac contractile ability impairment. Our data can be interesting for clinicians.

Molecular characterization of viruses associated with gastrointestinal infection in HIV-positive patients

BACKGROUND

Diarrhea is a major cause of morbidity and mortality among HIV-infected patients worldwide.

OBJECTIVE

We sought to determine the frequency of viral gastrointestinal infections among Brazilian HIV-infected patients with diarrhea.

METHODS

A collection of 90 fecal specimens from HIV-infected individuals with diarrhea, previously tested for the presence of bacteria and parasite was analyzed by polymerase chain reaction and sequence analysis for the presence of enteric viruses such as astrovirus, norovirus, rotavirus groups A, B and C, adenovirus, herpes simplex virus, Epstein-Barr virus, cytomegalovirus, and human bocavirus.

RESULTS

Twenty patients (22.2%; n = 90) were infected with parasites (11 single infections and nine coinfected with virus). Enteropathogenic bacteria were not found. Virus infections were detected in 28.9% (26/90) of the specimens. Cytomegalovirus was the most common virus detected (24.4%; 22/90). Coinfections with viruses and/or parasite were observed in 10 (11.1%) samples.

CONCLUSION

Gastrointestinal virus infections were more frequent than parasitic or bacterial infections in this patient population.

[A rare gastroenteritis pathogen: Cyclospora]

Cyclospora spp. which are coccidian parasites are rare gastroenteritis pathogens. The first cyclosporiasis case in Turkey was reported in 1998 in a patient with AIDS. In this paper we report a case of Cyclospora gastroenteritis, in a patient who was admitted to our hospital and who had had diarrhea, abdominal pain and nausea for ten days. In the anamnesis it was learned that he had travelled to the Black Sea region and had drunk muddy and cloudy water. His physical examination was normal except for increased bowel sounds. There were no leukocytes or erythrocytes in the direct microscopy of the stool and bacteriologic culture did not yield any enteropathogen. Cylospora oocyysts were seen in the parasitologic exmination. The patient was treated with cotrimaxasole (2x1,160/800 mg tablet). There was no pathogen in the repeated stool examination. Our case suggests that parasitologic examination should not be neglected in longlasting diarrhea cases and occasionally Cyclospora may be the causative agent.

[Gastrointestinal giardiasis associated with Helicobacter pylori]

The study involved 160 patients with chronic cholecystitis associated with chronic gastroduodenitis. Obtaining biopsy specimens of gastric mucosa and bile samples allowed to compare the microbial picture and the morphological structure of gastric mucosa in the same patient, to identify patterns of colonization of the stomach, 12 duodenal ulcer and gall bladder various microorganisms. At cytological examination was detected in the gall bladder G. lamblia in 47.5 +/- 3.95% of cases in the stomach--in 29.09 +/- 6.12% of cases. The frequency of H. pylori detection in biopsy of gastric mucosa amounted to 98.18 +/- 1.8% of cases, in 12-duodenum--93.75 +/- 1.9%, in the gall bladder--to 54.38 +/- 3.94%, in the bile duct--in 54.38 +/- 3.94%. It was found strict association between the detection of H. pylori and G. lamblia in the stomach--100% of H. pylori-infection combined with giardiasis. Morphological changes of gastric mucosa in the form of lymphoid infiltration detected mainly in the mixed-infection H. pylori and G. lamblia.

Association of Blastocystis subtype 3 and 1 with patients from an Oregon community presenting with chronic gastrointestinal illness

Chronic gastrointestinal illness of unknown etiology is a significant problem in the United States. Using a real-time LightCycler PCR assay we detected Blastocystis in nine patients from a metropolitan area of Corvallis, Oregon who presented with diarrhea, abdominal pain, fatigue, joint pain, skin rash and psychiatric co-morbidity. Phylogenetic analysis identified six infections with Blastocystis sp. subtype 3, and one with subtype 1, using the standard Stensvold nomenclature. Most patients with subtype 3 had previously tested negative with conventional parasitological diagnostics, had been symptomatic for over 4 years, and reported antibiotic failure.

Protein profile and morphometry of cultured human Blastocystis hominis from children with gastroenteritis and healthy ones

A total of 180 children of age group 5-12 years old in both sexes, of whom 90 were symptomatic and negative for other parasites, rotavirus or pathogenic bacteria. Another 90 children were asymptomatic, but with B. hominis in stools. Direct smear, formaline-ethyl acetate sedimentation concentration, kinyon carbol-fuchin stain, stool culture, enzyme immunoassay, culturing, morphometric study, gel electrophoresis and experimental infection of mice were done. The results showed that the central body cysts (CB), granular and multivacuolar forms isolated from symptomatic patients were larger than those from asymptomatic ones. The CB form was common compared to other forms and isolated from 104 cases. B. hominis infection was prevalent among males rather than females (60.5% versus 39.5%). The clinical data showed that diarrhea was the most common symptom (58.9%). The infection intensity had a direct relation with illness duration. The polyacrylamide gel electrophoresis showed that isolates from symptomatic and asymptomatic patients ranged between 24-130 kDa. All isolates showed similar banding patterns. Only minor differences was in low MW (30, 50 kDa) and in high MW (118 kDa) in samples from symptomatic patients. The histopathological examination of caecum, colon and small intestine of B. hominis mice infected from symptommatic patients showed infiltration with inflammatory cells and tissue invasion by the parasite.

Correlation between the presence of symptoms and the Giardia duodenalis genotype

Clinical manifestations of Giardia duodenalis infection vary from asymptomatic infection to chronic diarrhoea. We study the correlation between the presence of symptoms and the G. duodenalis genotype in 108 patients with giardiasis. Patient age ranged from 2 to 72 years old. We found a correlation between assemblage AII and symptomatic infections, and between assemblage B and asymptomatic infections in the overall patient group and in patients less than five years of age. Nevertheless, if only patients of more than five years of age were considered, no statistically significant relationship between assemblage and symptomatic or asymptomatic Giardia infections was found. In these patients, host factors may affect the presence of clinical manifestations more than Giardia assemblage.

An outbreak of gastroenteritis associated with intestinal parasites

Intestinal protozoa are one of the leading causes of waterborne outbreaks. Stool samples of 196 residents from a village of Izmir, using the public water supply, were collected during an outbreak of gastroenteritis. Patients were asked to fill out a questionnaire reporting on gender, age, gastrointestinal symptoms, whether or not there was a toilet in the house, their hygiene practices, and similar symptoms in the household members. Of the patients who had gastrointestinal symptoms (74.5%), diarrhea was observed in 69.5% whereas bloody and mucoid stools were observed in 20.4 %. The stool samples were examined for intestinal parasites by wet mount and trichrome stain and were also cultured in the Robinson medium. Pathogenic parasites were detected in 11 samples (5.6%) as follows: Giardia intestinalis in 7, Hymenolepis nana in 1 and Blastocystis hominis in 4. Entamoeba histolytica/dispar was not detected by direct wet mount in any of 8 patients who had E. histolytica/E. dispar in culture whereas it was detected in the trichrome stained slides of 3 patients. Amoeba prevalence in the 15-44 age-group was significantly high when compared with the 0-14 age group. The prevalence of pathogenic parasites was high among the people who had a toilet outdoors. Drinking water was thought to be a principal source of this outbreak.

[Diagnosis of intestinal-protozoa in patients with immune deficiency]

In our study, we tried to detect gastroenteritis causing intestinal protozoa in patients with immune deficiency and who suffered from diarrhea. We also tried to determine which laboratory methods should be used in detecting intestinal protozoon in these patients. Thirty-six immune deficient patients who had had diarrhea for more than 10 days and 44 immune deficient patients without diarrhea were included in the study. In stool samples taken from all cases, intestinal protozoa were detected using the conventional diagnostic methods including direct wet mount, trichrome and modified acid fast staining as well as serologic diagnostic methods such as ELISA, direct fluorescent antibody (DFA)] and the molecular method of polymerized chain reaction. In our study, we found that intestinal protozoan such as G. intestinalis; C. parvum, B. hominis and E. histolytica could be responsible for the long term diarrhea in patients with immune deficiency. If a pathogen is not detected in the feces by native Lugol (NL), DFA and MAF are suitable techniques for Cryptosporidium spp while ELISA or trichrome staining are suitable methods for E. histolytica. It was concluded in the study that the simple and inexpensive NL method is sufficient in the diagnosis of G. intestinalis and serological or molecular methods are unnecessary. Neutropenia in patients with immune deficiency did not enhance the frequent occurrence of intestinal protozoan infections; and also, in the cases with immune deficiency, it was found that the administration of steroid treatment was not a risk factor in intestinal protozoan disease.

Detection of Cryptosporidium spp and other intestinal parasites in children with acute diarrhea and severe dehydration in Rio de Janeiro

The objective of the present study was to estimate the frequency of infection by Cryptosporidium spp and other intestinal parasites in dehydrated children with gastroenteritis who were admitted to a pediatric hospital. Stool examinations from 218 children were performed. Cryptosporidium spp was identified in eighteen out of 193 stool samples (9.3%) subjected to safranin-methylene blue staining. Giardia lamblia was detected in ten out of 213 (4.7%) samples examined via the direct or Ritchie methods. Other parasites identified were Ascaris lumbricoides (4.2%), Blastocystis hominis (1.4%), Entamoeba coli (0.9%), Entamoeba histolytica/Entamoeba dispar (0.5%), Endolimax nana (0.5%), Trichuris trichiura (0.5%) and Enterobius vermicularis (0.5%).

An outbreak of cryptosporidiosis suspected to be related to contaminated food, October 2006, Sakai City, Japan

On October 17, 2006, the Sakai City Public Health Center received a report of acute gastroenteritis among 4 members from the same company who had eaten raw meat dish called "Yukke: Korean-style beef tartar" and raw liver at a rotisserie in Sakai City on October 7. Based on information from interviews, the median incubation period was 5.5 (range, 5-7 days), and the median length of illness was 7 days (range, 4-10 days). The illness was characterized by a prolonged incubation period, non-bloody watery diarrhea, reduced vomiting, and light fever, which led us to suspect an enteric protozoan infection. Stool specimens obtained from 3 of the 4 symptomatic patients were positive for Cryptosporidium oocysts. They, along with 2 food workers, were negative for food poisoning bacteria or Norovirus. Genotyping of the Cryptosporidium isolates by direct sequencing of PCR products revealed that all the isolates were the C. parvum genotype II (bovine) and the subgenotype of IIa with 100 % homology with respective 18S rRNA and Cpgp40/15 genes. Positive implementation of tests for enteric protozoa including Cryptosporidium is necessary in the differential diagnosis of suspected foodborne gastroenteritis, particularly when it is characterized by a prolonged incubation period and severe watery diarrhea. In fact, we were able to diagnose the illness as cryptosporidiosis without waiting for the results of bacteriological and virological examinations, and thus prevented the possible occurrence of a secondary infection through an ill patient who works as cooking personnel in the company.

Molecular characterization of human isolates of Giardia duodenalis from Ethiopia

Giardia duodenalis, a flagellated protozoan, represents a common cause of gastroenteritis in Ethiopia, however very little information is available on the epidemiology and transmission routes of this pathogen, and a genetic characterization of the parasite has never been attempted in this country. The aim of this study was the genetic analysis of human isolates of G. duodenalis collected in different localities across the country, both from urban and rural areas. A fragment of the beta-giardin gene was amplified by nested PCR and analyzed by restriction and sequence analyses. Of the 59 isolates examined, 31 (52%) were typed as assemblage A and 13 (22%) as assemblage B. A strong correlation between the presence of symptoms and infection with assemblage B was observed. The remaining 15 (25%) isolates were typed as mixed infections by PCR-RFLP, specifically, A+F (in seven isolates) and A+B (in eight isolates). Sequencing of the A+F products confirmed the presence of assemblage F in three isolates, whereas the remaining four were identified as assemblage A. The detection of assemblage F, a cat-specific assemblage that to date has not been associated with human infections, was not able to be confirmed by the analysis of two commonly used markers (small subunit ribosomal RNA and triosephosphate isomerase). The analysis of the one isolate that was successfully amplified with the glutamate dehydrogenase primers unambiguously identified it as G. duodenalis, yet it was distinct from the established A and F sequences; thus the exact genetic identity of these isolates remains unclear.

Outbreak of waterborne cryptosporidiosis associated with low oocyst concentrations

Water treatment plants in the United Kingdom at significant risk of cryptosporidiosis and using conventional filtration methods have been required to install 24-h monitoring systems since April 2000. No major waterborne outbreaks have been described since 2001. Small outbreaks have been associated with water. This paper describes such an outbreak. Data from a local multi-agency surveillance system was used to describe the outbreak, including mapping cases against water supply zones. A case-control study investigated hypotheses raised. All cases were genotype 1. Early cases were in the supply zone of a surface water-treatment plant that had met treatment standards. Later cases included residents in a different supply zone that temporarily received water from the implicated plant. Cases reported more consumption of domestic mains water than controls. Descriptive and analytical epidemiology thus supported drinking water as a source of cryptosporidiosis from a plant meeting regulatory requirements. The evidence for setting drinking-water standards needs review.

[The Giardia epidemic in 2004 and out-of-hours service in Bergen]

BACKGROUND

From October to December 2004, 1,300 individuals were infected with Giardia lamblia in Bergen, Norway. The aim of this study was to explore this epidemic from the perspective of an accident and emergency department in Bergen.

MATERIAL AND METHODS

Patient files from 2004 were searched retrospectively in Bergen accident and emergency department, for patients with a diagnosis of infectious gastroenteritis or with the word Giardia: in the laboratory section of their files. Information from the files where Giardia tests had been done, was collected and analysed.

RESULTS

A total of 1,603 patients with infectious gastroenteritis were found. The number of patients with gastroenteritis more than doubled six weeks before the Giardia epidemic was recognized. 420 patients had been tested for Giardia, and 200 of them had positive tests. Most of the patients with positive Giardia tests were in their twenties. Symptoms and findings of the gastroenteritis patients with positive Giardia tests were unspecific and not very alarming.

INTERPRETATION

The Giardia epidemic probably started six weeks before it was recognized as such. Giardia infection is difficult to recognize on clinical grounds alone.