Campylobacter jejuni infection and virulence-associated genes in children with moderate to severe diarrhoea admitted to emergency rooms in northeastern Brazil

Abstract

Campylobacter is an important cause of foodborne gastroenteritis. We determined the occurrence of Campylobacter jejuni and Campylobacter coli, using culture-based methods and PCRs targeting virulence-associated genes (VAGs) among children aged ¡14 years who were treated for diarrhoea at emergency rooms in northeastern Brazil. Genomic DNA was extracted directly from stool samples collected from 366 children. A questionnaire was also applied to qualify the clinical conditions presented by each child at the time of admission. C. jejuni and C. coli were detected in 16.4 % (60/366) and 1.4 % (5/366) of the diarrhoeal samples, respectively, by PCR, a much higher proportion than that detected by conventional methods. C. jejuni VAGs were detected in the following proportions of hipO-positive samples: ciaB, 95 % (57/60); dnaJ, 86.7 % (52/60); racR, 98.3 % (59/60); flaA, 80 % (48/60); pldA, 45 % (27/60); cdtABC, 95 % (57/60); and pVir 0 % (0/ 60). Particular symptoms, such as blood in faeces, vomiting, fever, and/or abdominal pain, were not associated with detection of C. jejuni nor were they associated with any particular VAG or combination of VAGs (P.0.05). C. jejuni and its VAGs were detected in a substantial proportion of the children admitted. Further efforts shall be directed towards elucidating whether these genetic factors or their expressed proteins play a role in Campylobacter pathogenesis. INTRODUCTIONThe genus Campylobacter, a group of thermotolerant, microaerophilic, Gram-negative bacteria, includes a number of pathogens that primarily cause gastrointestinal disease in humans, particularly Campylobacter jejuni and Campylobacter coli. Campylobacter-associated gastroenteritis is thought to occur through zoonotic transmission, being acquired from exposure to tainted food and/or contaminated drinking water (Sherman et al., 2010). Campylobacter infection frequently presents as self-limiting acute enteritis with diarrhoea, malaise, fever and abdominal pain, sometimes with vomiting and the presence of blood in faeces (Allos, 2001); disruption of epithelial cells and inflammation of the intestinal mucosa are hallmark features of severe cases (Beltinger et al., 2008). C. jejuni and C. coli cause significant morbidity worldwide, especially in children (Amieva, 2005;Tam et al., 2003;Wang et al., 2008; Fernández et al., 2008).Adherence and colonization are crucial steps in the pathogenesis of C. jejuni. Flagella have a major role in invasion; markedly reduced internalization in vitro has been reported with flaA 2 C. jejuni mutants (Wassenaar, 1997). The genes racR and dnaJ are determinants for C. jejuni colonization and are presumably expressed in response to conditions encountered in the intestinal microenviroment, such as differences in temperature between environmental reservoirs and human intestines (Konkel et al., 1998; Brás et al., 1999 antigen B protein, which confers invasive properties, as shown by C. jejuni ciaB null mutants which display a significant reduction in internalization (Konkel et al., 1999). Also, ...

A Molecular Survey of Campylobacter jejuni and Campylobacter Coli Virulence and Diversity

“…This finding is in agreement with the studies by other investigators who did not find vir B11 gene among Campylobacter isolates of children from Brazil and Bangladesh [23, 24]. However, a few other studies indicated the prevalence of vir B11 to be 10.7-22.7% among clinical isolates [21, 25].…”

“…infections in children with moderate to severe diarrhea [21-23]. Similarly, these genes were also detected within all of our isolates.…”

Pentaplex PCR Assay for Detection of Hemorrhagic Bacteria from Stool Samples

“…Implementation of the molecular tools increased the detection frequency of enteric pathogens 3-fold (19.2% compared to 6.4% with conventional methods) (7). Moreover, a considerable proportion of positive fecal samples previously confirmed as negative by culture methods have been detected by using molecular tools (14). The present study validated a multiplex PCR assay for the detection of hemorrhagic bacteria in stool samples.…”

“…simultaneously in stool, but results were seen within 4 h in comparison to 3 to 5 days by conventional methods. Although there are numerous reports on PCR assays for the detection of hemorrhagic bacteria (15,16), only a few of these assays have incorporated internal controls (14,17). The presence of PCR inhibitors (like bilirubin, bile salts, and heme in the feces) in stool samples may inhibit amplification and limit the usefulness of the PCR technique (18,19).…”

Campylobacterinfections in children exposed to infected backyard poultry in Egypt

“…Higher rates were recorded from chicken giblets (23·5%) compared to duck (19%), turkey (14·5%) and squab (4%) [25]. Previous studies in other countries have also identified C. jejuni as the most common isolate in poultry with C. coli being more frequently isolated from pigs and sheep [14,[26][27][28][29]. Generally, the population of pigs in Egypt is much lower than the poultry populations due to the popular consumption of poultry and the large-scale government culling of around 300 000 pigs during the 2009 H1N1 'swine flu' pandemic [30].…”