Campylobacter concisus pathotypes induce distinct global responses in intestinal epithelial cells.

The epithelial response to the opportunistic pathogen Campylobacter concisus is poorly characterised. Here, we assessed the intestinal epithelial responses to two C. concisus strains with different virulence characteristics in Caco-2 cells using RNAseq, and validated a subset of the response using qPCR arrays. C. concisus strains induced distinct response patterns from intestinal epithelial cells, with the toxigenic strain inducing a significantly more amplified response. A range of cellular functions were significantly regulated in a strain-specific manner, including epithelial-to-mesenchymal transition (NOTCH and Hedgehog), cytoskeletal remodeling, tight junctions, inflammatory responses and autophagy. Pattern recognition receptors were regulated, including TLR3 and IFI16, suggesting that nucleic acid sensing was important for epithelial recognition of C. concisus. C. concisus zonula occludens toxin (ZOT) was expressed and purified, and the epithelial response to the toxin was analysed using RNAseq. ZOT upregulated PAR2 expression, as well as processes related to tight junctions and cytoskeletal remodeling. C. concisus ZOT also induced upregulation of TLR3, pro-inflammatory cytokines IL6, IL8 and chemokine CXCL16, as well as the executioner caspase CASP7. Here, we characterise distinct global epithelial responses to C. concisus strains, and the virulence factor ZOT, and provide novel information on mechanisms by which this bacterium may affect the host.

Campylobacter concisus pathotypes are present at significant levels in patients with gastroenteritis.

Given that Campylobacter jejuni is recognized as the most common cause of bacterial gastroenteritis worldwide, recent findings showing comparable levels of Campylobacter concisus in patients with gastroenteritis would suggest that this bacterium is clinically important. The prevalence and abundance of Campylobacter concisus in stool samples collected from patients with acute gastroenteritis was examined using quantitative real-time PCR. The associated virulence determinants exotoxin 9 and zonula occludens toxin DNA were detected for Campylobacter concisus-infected samples using real-time PCR. Campylobacter concisus was detected at high prevalence in patients with gastroenteritis (49.7 %), higher than that observed for Campylobacter jejuni (∼5 %). The levels of Campylobacter concisus were putatively classified into clinically relevant and potentially transient subgroups based on a threshold developed using Campylobacter jejuni levels, as the highly sensitive real-time PCR probably detected transient passage of the bacterium from the oral cavity. A total of 18 % of patients were found to have clinically relevant levels of Campylobacter concisus, a significant number of which also had high levels of one of the virulence determinants. Of these patients, 78 % were found to have no other gastrointestinal pathogen identified in the stool, which strongly suggests a role for Campylobacter concisus in the aetiology of gastroenteritis in these patients. These results emphasize the need for diagnostic laboratories to employ identification protocols for emerging Campylobacter species. Clinical follow-up in patients presenting with high levels of Campylobacter concisus in the intestinal tract is needed, given that it has been associated with more chronic sequelae.

The interplay between Campylobacter and Helicobacter species and other gastrointestinal microbiota of commercial broiler chickens.

BACKGROUND: Poultry represent an important source of foodborne enteropathogens, in particular thermophilic Campylobacter species. Many of these organisms colonize the intestinal tract of broiler chickens as harmless commensals, and therefore, often remain undetected prior to slaughter. The exact reasons for the lack of clinical disease are unknown, but analysis of the gastrointestinal microbiota of broiler chickens may improve our understanding of the microbial interactions with the host. METHODS: In this study, the fecal microbiota of 31 market-age (56-day old) broiler chickens, from two different farms, was analyzed using high throughput sequencing. The samples were then screened for two emerging human pathogens, Campylobacter concisus and Helicobacter pullorum, using species-specific PCR. RESULTS: The gastrointestinal microbiota of chickens was classified into four potential enterotypes, similar to that of humans, where three enterotypes have been identified. The results indicated that variations between farms may have contributed to differences in the microbiota, though each of the four enterotypes were found in both farms suggesting that these groupings did not occur by chance. In addition to the identification of Campylobacter jejuni subspecies doylei and the emerging species, C. concisus, C. upsaliensis and H. pullorum, several differences in the prevalence of human pathogens within these enterotypes were observed. Further analysis revealed microbial taxa with the potential to increase the likelihood of colonization by a number of these pathogens, including C. jejuni. CONCLUSION: Depletion of these taxa and the addition of taxa that compete with these pathogens, may form the basis of competitive exclusion strategies to eliminate them from the gastrointestinal tract of chickens.

Vibrio cholerae strains possess multiple strategies for abiotic and biotic surface colonization.

Despite its notoriety as a human pathogen, Vibrio cholerae is an aquatic microbe suited to live in freshwater, estuarine, and marine environments where biofilm formation may provide a selective advantage. Here we report characterization of biofilms formed on abiotic and biotic surfaces by two non-O1/O139 V. cholerae strains, TP and SIO, and by the O1 V. cholerae strain N16961 in addition to the isolation of 44 transposon mutants of SIO and TP impaired in biofilm formation. During the course of characterizing the mutants, 30 loci which have not previously been associated with V. cholerae biofilms were identified. These loci code for proteins which perform a wide variety of functions, including amino acid metabolism, ion transport, and gene regulation. Also, when the plankton colonization abilities of strains N16961, SIO, and TP were examined, each strain showed increased colonization of dead plankton compared with colonization of live plankton (the dinoflagellate Lingulodinium polyedrum and the copepod Tigriopus californicus). Surprisingly, most of the biofilm mutants were not impaired in plankton colonization. Only mutants impaired in motility or chemotaxis showed reduced colonization. These results indicate the presence of both conserved and variable genes which influence the surface colonization properties of different V. cholerae subspecies.

Preoperative chemoradiotherapy prior to esophagectomy in elderly patients is not associated with increased morbidity.

BACKGROUND: Preoperative chemotherapy and radiation therapy are often administered to patients with esophageal cancer. Despite an aging population, little data exist regarding feasibility of preoperative therapy in elderly patients. METHODS: Between January 1997 and December 2002, 312 consecutive patients underwent esophagectomy for esophageal cancer at our institution. Outcomes of patients 70 years old, who underwent preoperative therapy (n = 35; group II), were compared with those of patients who did not (n = 39; group I) and with those of patients younger than 70 years old who received preoperative therapy (n = 165; group III). RESULTS: The median age was 75 years old for group I and 72 years for group II (p < 0.001). The patients in group II were of more advanced clinical stage (p < 0.001). There were no differences in performance status, comorbidities, or preoperative symptoms between the two groups. Similar proportions of patients in the groups I and II underwent a transhiatal approach (52.5% vs 42.8%, p = not significant [NS]). Perioperative mortality for groups I and II was 0% and 3%, respectively (p = NS). Group II received more perioperative blood transfusions (71.4% vs 48.7%, p = 0.047). There were no differences in the rates of postoperative cardiac, pulmonary, neurologic, gastrointestinal, or anastomotic complications. Compared with group III, group II patients had higher rates of postoperative atrial arrhythmias (p = 0.013) and perioperative blood transfusions (p = 0.004). CONCLUSIONS: Elderly patients receiving preoperative therapy for esophageal cancer do not have an increased incidence of major postoperative complications. Elderly patients receiving preoperative therapy are more likely to develop postoperative atrial arrhythmias and require transfusion than younger patients.