Stool Specimens Of Children Research Articles

Molecular epidemiology ofEscherichia colidiarrhoea in children in Tehran

From July to December 2003, four categories of diarrhoeagenic Escherichia coli were investigated in Tehranian children with acute diarrhoea. Stool specimens of children under 5 years of age with diarrhoea (n=200) and matched controls (n=200) without diarrhoea were studied for the presence of entero-aggregative (EAEC), enteropathogenic (EPEC), enterotoxigenic (ETEC) and Shiga toxin-producing (STEC) E. coli by PCR identification of six different genes of diarrhoeagenic E. coli. STEC isolates were typed by O157 and H7 antisera. EAEC was the most prevalent category and was found in 24% of patients with diarrhoea and 8% of controls (p<0.0001). ETEC was isolated in 15.5% of patients with diarrhoea but not in any controls ( p<0.0001), STEC in 15% of patients and 2% of controls (p<0.0001) and EPEC in 6% of patients and 5% of controls. Of 30 STEC isolates from patients with diarrhoea, seven were O157:H7 and 23 were non-O157:H7.

Enteroaggregative and cell-detaching Escherichia coli strains among Polish children with and without diarrhea.

To determine the association of enteroaggregative (EAEC) and cell-detaching (CDEC) Escherichia coli with diarrhea of unknown origin among children from Wrocław (Poland), E. coli strains isolated from stool specimens of children with diarrhea were examined for mannose-resistant adherence to HEp-2 cells. EAEC were isolated from 10 of 39 (26%) children examined with diarrhea and 4 of 20 (20%) age-matched controls. CDEC were present in 14 (36%) cases of diarrhea and 7 (35%) healthy subjects. Cell-detaching activity was distinctly associated with hemolysin production. Among hemolytic CDEC strains cytotoxic necrotizing factor 1 (CNF1) synthesis prevailed among isolates obtained from cases of diarrhea (57%) in comparison with isolates obtained from healthy controls (14.3%). Although neither EAEC nor CDEC E. coli strains were associated with diarrhea of children in this setting, there were differences among EAEC and CDEC strains isolated from children with and without diarrhea.

Prevalence of enteroaggregative Escherichia coli among children with and without diarrhea in Switzerland.

In a prospective study between July 1999 and September 2000, stool specimens of children below the age of 16 years with (n = 187) and without (n = 137) diarrhea were tested for the presence of enterovirulent bacteria by standard culture methods and by PCR. Targets for the PCR were the plasmid pCVD432 for enteroaggregative Escherichia coli (EAEC), the verotoxin 1 and verotoxin 2 genes for enterohemorrhagic E. coli, ipaH for enteroinvasive E. coli (EIEC) and Shigella spp., genes coding for heat-stable and heat-labile toxins for enterotoxigenic E. coli (ETEC), and the eaeA gene for enteropathogenic E. coli. The following bacteria could be associated with diarrhea: Salmonella enterica (P = 0.001), Campylobacter spp. (P = 0.036), ETEC (P = 0.012), and EAEC (P = 0.006). The detection of EAEC, ETEC, and S. enterica was strongly associated with a history of recent travel outside of Switzerland. EAEC isolates were found in the specimens of 19 (10.2%) of 187 children with diarrhea and in those of 3 (2.2%) of 137 children without diarrhea (P = 0.006) and were the most frequently detected bacteria associated with diarrhea. Among the children below the age of 5 years, the specimens of 18 (11.9%) of 151 with diarrhea were positive for EAEC, while this agent was found in the specimens of 2 (2.2%) of 91 controls (P = 0.007). Enteropathogenic E. coli isolates were found in the specimens of 30 (16.4%) of the patients and in those of 15 (10.9%) of the controls, with similar frequencies in all age groups (P > 0.05). We conclude that EAEC bacteria are involved in a significant proportion of diarrhea cases among children. Children younger than 5 years of age are more often affected by EAEC than older children.

Utilization of a Latex Agglutination Test for the Rapid Detection of Shigella in Stool Specimens of Children with the hemolytic Uremic Syndrome

Background: The hemolytic uremic syndrome (HUS) is one of the important causes of acute renal failure in childhood. It is classified into diarrhea-associated and atypical cases. Verotoxin-associated HUS is the most common type of the disease. It is characterized by the sudden onset of hemolytic anemia with fragmented erythrocytes, thrombocytopenia, and acute renal failure after a prodromal illness of acute gastroenteritis usually with bloody diarrhea. In addition to specific strains of E. Coli, Shigella dysentriae type 1 can be an important cause of HUS. Cases with Shigella dysentriae have ahigher mortality rate, and a greater incidence of complications and extra-renal manifestations compared with patients who have HUS related to E. Coli. Therefore, it would be important to have a rapid way to detect Shigella associated HUS, in order to anticipate its complications, and allow the administration of aggressive managements to such patients. Conventional stool cultures are labour-demanding and time-consuming, and therefore may not be the ideal method for the detection of certain stool pathogens in acute situation like the hemolytic uremic syndrome. A rapid, cost-effective and reliable method for the detection and identification of stool pathogens in stool specimens from these patients would be of great value. Objectives: The aim of this work is to evaluate the utilization of a rapid latex agglutination test in comparison to conventional stool culture to determine the incidence of Shigella dysentriae among children with the HUS in Egyptian children, and to determine whether this test could be used as an alternative to conventional stool culture in this situation. Methods: In this study, a latex agglutination test (Bactigen Salmonella/Shigellalatex agglutination slide test; Wampole Laboratories, Cranbury, NJ) was evaluated as a test for the detection of Shigella antigens in Gram Negative Broth for the early and rapid detection of Shigella dysentriae infection in infants and children presenting with evidence of the hemolytic uremic syndrome. Results: Utilization of conventional stool culture revealed that 3 of 7 cases of the HUS were positive for Shigella dysentriae, an incidenceof 17%. Utilization of the BSST latex agglutination test for Shigella antigen shows that 5 of 17 cases of the HUS were positive for Shigella dysentriae (29.5%). Also, all 3 cases in which stool culture was positive for Shigella dysentriae were also positive by the BSST test, with no false negatives (sensitivity 100%, positive predictive value 80%). However, of the 14 cases of HUS who were negative for Shigella by culture, two cases were positive for Shigella by the BSST latex agglutination test (specificity 85%, negative predictive value 100%). Conclusions: The BSST latex agglutination test is a useful method for the rapid detection of Shigella antigens in stool specimens from infants and children with the HUS. Due to its rapidity, it can provide a quick answer and allow the anticipation if the need for more aggressive managements for cases of HUS associated with Shigella gastroenteritis. Its sensitivity appears to be excellent. While its specificity appears to be low, with a high incidence of false positive results. However, in such an acute situation, it is much more important not to miss a positive case than to over-diagnosis a case with Shigellosis. Also, conventional stool culture can correctly identify the true pathogen in false positive cases.

Rotavirus infection in children in Japan

Currently, a high morbidity of rotavirus diarrhea has been seen in children in developed and developing countries. Improvement of the vaccines is necessary in order to reduce the burden of diarrhea caused by rotavirus. A survey of rotavirus infection from diarrheal stool specimens in children of seven regions in Japan was conducted from 1984 to 1999. The present study discusses the survey results and reviews the national and international data of more than 23 papers and congress proceedings about rotavirus infection in Japan. We analyze the prevalence of rotavirus infection in acute diarrheal in- and outpatients, the distribution of rotavirus G-serotypes and surveillance data for seasonality and age groups in Japan. The data indicated that rotavirus is the most important cause of diarrhea in Japan among young children, with the prevalence ranging from approximately 9.7 to 88%. The most common rotavirus strains belonged to serotype G1, specifically since 1993. Serotypes G2, G3 and G4 had also been documented to be predominantly based in the area and year before 1992. However, untypeable rotavirus strains had been found each year, with a prevalence up to 56.7% which suggests that rare serotypes (except G1-4) or new serotypes might exist. Unexpectedly, in Tokyo and Sapporo from 1998 to 1999, G9 was found to be the first most prevailing serotype with a high prevalence of 52.9 and 71.4%, respectively. Despite these data from different geographic areas, the year under investigation was relatively clear in respect to seasonality, with a peak of rotavirus activity in late winter (February) through early spring (March). Age distribution had also characterized that the infection was predominant among children aged 1-2 years of age, although it was also common in children of 2-3 years. In addition, mixed infection with bacteria was documented.

Serotypes of human rotaviruses in 7 regions of Japan from 1984 to 1997.

Human rotavirus (HRV) serotypes were studied from diarrheal stool specimens in children in 7 regions of Japan (Sapporo, Tokyo, Maizuru, Osaka, Kagawa, Kurume, and Saga) from 1984 to 1997 by enzyme immunoassay (EIA) with serotype-specific monoclonal antibodies against serotypes 1, 2, 3, and 4. In addition, reverse transcription-polymerase chain reaction (RT-PCR) was conducted for analysis of "others" which included nonserotypable and mixed-serotype rotavirus specimens by EIA. In 3756 rotavirus-positive specimens, serotype 1 was detected in 2649 (70.5%), serotype 2 in 362 (9.6%), serotype 3 in 232 (6.2%) and serotype 4 in 196 (5.2%). Overall, serotype 1 was predominant from 1984 to 1997, although there were a few cases in which serotype 2, 3 and 4 became predominant based on area and year. The frequency of serotype 1 has gradually increased since 1993. Twenty two, 2, 3 and 1 among 57 specimens of "others" by EIA from Tokyo, Maizuru, Sapporo and Kurume in 1995-1996 and 1996-1997 were determined as serotypes 1, 2, 3, and 9 by RT-PCR, respectively.

Markers of Virulence Among Prospectively Acquired Putative EnteropathogenicEscherichia ColiSerogroups

We assessed the frequency of proposed enteropathogenic virulence factor genes (eaeA and eaf) by genetic amplification for a series of prospectively collected putative enteropathogenic Escherichia coli serogroup isolates that were acquired from the stool specimens of children. Among 102 isolates, eaeA and eaf markers were determined among 27.5% and 4.9%, respectively. Eaf positivity was found to be coexisting in only a minority of eaeA+ E. coli; the eaeA+/eaf- genotype was most common among strains that had evidence of at least one virulence marker. When clinical variables were compared for two groups of patients whose strains did or did not possess eaeA, the eaeA+ group was more likely to have had an acute diarrheal illness (P = .05) and less likely to have had an underlying chronic illness (P = .03). Localized adherence in vitro was easily recognized for eaeA+/eaf+ E. coli but eaeA+/eaf- isolates were less consistent in manifesting this phenotype. The availability of genetic amplification technologies has the potential to rekindle diagnostic interests in this area, although a rational approach has yet to be defined.

Enteric adenovirus type 41 isolates: cloning, physical maps and diversity in restriction enzyme cleavage pattern.

Adenovirus (Ad) type 40 and 41 DNAs were directly extracted from stool specimens of children with gastroenteritis. Two new strains of Ad41, Sanekata and Ehime strain, were cloned and their restriction maps were constructed. The left terminal end of the cloned Ad41 genome, EcoRI-E fragment of the Sanekata strain and EcoRI-F fragment of the Ehime strain, had transforming ability in rat 3Y1 cells. Only one of the 35 isolates of Ad40 tested showed a different restriction profile, while three different restriction profiles were found in DNAs from Ad41 isolates.