Comparison of immunochromatography, PCR and culture methods for the detection of Campylobacter bacteria

Genetic Signature and Serocompatibility Evidence for Drug Resistant Campylobacter jejuni

Campylobacteriosis, a foodborne illness, is one of the world′s leading causes of gastrointestinal illness. This study investigates the link between human campylobacteriosis and the consumption of potentially contaminated food with Campylobacter jejuni. Three hundred sixty samples were collected from humans, chicken cloaca, raw chicken meat, unpasteurized milk, and vegetables. The chickens were obtained from licensed and non-licensed slaughterhouses, and only the necks and wings were studied. Samples were enriched under microaerobic conditions then cultured on the modified charcoal cefoperazone deoxycholate agar. Bacteria was identified by staining, biochemical testing, and molecular identification by the polymerase chain reaction for the virulence genes; hipO, asp, dnaJ, cadF, cdtA, cdtB, and cdtC. The genomic homogeneity of C. jejuni between human and chicken isolates was assessed by the serological Penner test and the pulse field gel electrophoresis (PFGE). Campylobacter was not detected in the vegetables and pasteurized milk, though, only twenty isolates from chickens and clinical samples were presumed to be Campylobacter based on their morphology. The biochemical tests confirmed that five isolates were C. coli, and fifteen isolates were C. jejuni including two isolates from humans, and the remaining were from chickens. The colonization of C. jejuni in chickens was significantly lower in necks (6.66%) obtained from licensed slaughterhouses compared to those obtained from non-licensed slaughterhouses (33.3%). The antimicrobial susceptibility test showed that all identified C. jejuni isolates were resistant to antibiotics, and the majority of isolates (53.5%) showed resistance against six antibiotics, though, all isolates were resistant to ciprofloxacin, tetracycline, and aztreonam. The Penner test showed P:21 as the dominant serotype in isolates from humans, necks, and cloaca. The serohomology of C. jejuni from human isolates and chicken necks, wings, and cloaca was 71%, 36%, 78%, respectively. The PFGE analysis of the pattern for DNA fragmentation by the restriction enzyme Smal showed a complete genotypic homology of C. jejuni human isolates and chicken necks compared to partial homology with cloacal isolates. The study brings attention to the need for effective interventions to ensure best practices for safe poultry production for commercial food chain supply to limit infection with foodborne pathogens, including Campylobacter.

Experience of <italic>Campylobacter</italic> gastroenteritis in Korean children: Single-center study

Although Campylobacter is the main cause for bacterial acute gastroenteritis (AGE), there has been no notable clinical research into it, especially for Korean children. In this study, we share our experience of clinical, laboratory and image findings with Campylobacter AGE. Methods Between May 2013 and June 2016, children diagnosed as having Campylobacter AGE were retrospectively enrolled in our study. Campylobacter AGE was considered diagnosed when a patient had symptoms of bacterial AGE and a positive Campylobacter result in stool using multiplex PCR. Results Among 539 patients with suspected bacterial AGE, 31 (5.8%) patients had a positive result for Campylobacter. The average age of the 31 patients was 10.2 ± 5.0 years with a range between 1.1 and 16.9 years. Eighteen (58%) of the total patients were hospitalized between June and August. Diarrhea (93.5%), abdominal pain (83%) and fever (83%) were common symptoms. For 20 patients (65%), diarrhea lasted for less than three days, and fever lasted for 2.1 days on average. Among the 20 patients subjected to imaging studies, 12 patients (60%) showed bowel wall thickening on the right side of colon. In blood tests of 30 patients, 22 (73%) and 29 (97%) patients exhibited leukocytosis and elevated C-reactive protein, respectively. During treatment for Campylobacter AGE, prediagnostic empirical antibiotics were used for 6 (19%) patients. All patients recovered without complications. Conclusions Among the children with suspected bacterial AGE, 5.8% had a positive result on Campylobacter in stool using multiplex PCR. Therefore, we observe that Campylobacter AGE should be considered in school-age children who have diarrhea, fever, and abdominal pain.

Multiplex PCR Assay for Identifi cation and Differentiation of Campylobacter jejuni and Campylobacter coli Isolates

INTRODUCTION

Campylobacter spp. are important causative agents of gastrointestinal infections in humans. The most frequently isolated strains of this bacterial genus are Campylobacter jejuni and Campylobacter coli. To date, genetic methods for bacterial identification have not been used in Bulgaria. We optimized the multiplex PSR assay to identify Campylobacter spp. and differentiate C. jejuni from C. coli in clinical isolates. We also compared this method with the routinely used biochemical methods.

AIM

To identify Campylobacter spp. and discriminate C. coli from C. jejuni in clinical isolates using multiplex PCR assay.

MATERIALS AND METHODS

Between February 2014 and January 2015 we studied 93 stool samples taken from patients with diarrheal syndrome and identified 40 species of Campylobacter spp. in them. The clinical material was cultured in microaerophilic atmosphere, the isolated strains being biochemically diff erentiated (hydrolysis of sodium hippurate for C. jejuni, and hydrolysis of indoxyl acetate for C. coli). DNA was isolated from the strains using QiaAmp MiniKit (QIAGEN, Germany). Twenty strains were tested with multiplex PCR for the presence of these genes: cadF, characteristic for Campylobacter spp., hipO for C. jejuni and asp for C. coli.

RESULTS AND DISCUSSION

The biochemical tests identified 16 strains of C. jejuni, 3 strains of C. coli, and 1 strain of C. upsaliensis. After the multiplex PCR assay the capillary gel electrophoresis confirmed 16 strains of C. jejuni, 2 strains of C. coli and 2 strains of Campylobacter spp. - because of the presence of the gene cadF. C. jejuni has the gene hipO, and it is possible that this gene may not be expressed in the biochemical differentiation yielding a negative reaction as a result. In comparison, we can conclude that the genetic differentiation is a more accurate method than the biochemical tests.

CONCLUSION

The multiplex PCR assay is a fast, accurate method for identifi cation of Campylobacter spp. which makes it quite necessary in the clinical diagnostic practice.

Accurate detection of Campylobacter spp. antigens by immunochromatography and enzyme immunoassay in routine microbiological laboratory

Campylobacter spp. are fastidious microorganisms, and their detection by culture depends on the freshness of the stool sample and the skills of the laboratory staff. To improve laboratory diagnosis, assays for the detection of specific antigens have been developed. Here, we evaluated two assays for the detection of Campylobacter spp.-specific antigens, i.e., one immunochromatographic test and one enzyme-linked immunosorbent assay (EIA), in 38 frozen Campylobacter spp.-positive specimens and prospectively in 533 fresh stool samples with a conventional enzyme immunoassay (EIA) and culture. Both assays were positive for 36 samples with Campylobacter jejuni and one with Campylobacter coli among 38 Campylobacter spp.-positive frozen samples. One Campylobacter lari-positive sample was identified by the immunochromatographic assay (ICA) only. In a prospective study performed within the course of routine microbiology, both assays were positive for 24/25 C. jejuni culture-positive samples (positive percent agreement, 96.0% [95% CI: 78.9-100%]). ICA and EIA also were positive for 14 and 10 culture-negative samples, respectively (negative percent agreement: ICA, 97.2% [95% CI: 95.4-98.4%]; EIA, 98.0% [95% CI: 96.4-99.0%]). In conclusion, the high agreement between both antigen-detection assays and culture indicates that both assays may be initially performed followed by culture only upon a positive test result.

Detection of Campylobacter in stool and determination of significance by culture, enzyme immunoassay, and PCR in developing countries

Campylobacter is a common bacterial enteropathogen that can be detected in stool by culture, enzyme immunoassay (EIA), or PCR. We compared culture for C. jejuni/C. coli, EIA (ProSpecT), and duplex PCR to distinguish Campylobacter jejuni/C. coli and non-jejuni/coli Campylobacter on 432 diarrheal and matched control stool samples from infants in a multisite longitudinal study of enteric infections in Tanzania, Bangladesh, and Peru. The sensitivity and specificity of culture were 8.5% and 97.6%, respectively, compared with the results of EIA and 8.7% and 98.0%, respectively, compared with the results of PCR for C. jejuni/C. coli. Most (71.6%) EIA-positive samples were positive by PCR for C. jejuni/C. coli, but 27.6% were positive for non-jejuni/coli Campylobacter species. Sequencing of 16S rRNA from 53 of these non-jejuni/coli Campylobacter samples showed that it most closely matched the 16S rRNA of C. hyointestinalis subsp. lawsonii (56%), C. troglodytis (33%), C. upsaliensis (7.7%), and C. jejuni/C. coli (2.6%). Campylobacter-negative stool spiked with each of the above-mentioned Campylobacter species revealed reactivity with EIA. PCR detection of Campylobacter species was strongly associated with diarrhea in Peru (odds ratio [OR] = 3.66, P < 0.001) but not in Tanzania (OR = 1.56, P = 0.24) or Bangladesh (OR = 1.13, P = 0.75). According to PCR, Campylobacter jejuni/C. coli infections represented less than half of all infections with Campylobacter species. In sum, in infants in developing country settings, the ProSpecT EIA and PCR for Campylobacter reveal extremely high rates of positivity. We propose the use of PCR because it retains high sensitivity, can ascertain burden, and can distinguish between Campylobacter infections at the species level.