Campylobacter Jejuni Research Articles

The antimicrobial effect of eugenol against Campylobacter jejuni on experimental raw chicken breast meat model

AbstractCampylobacter jejuni is the predominant bacterial cause of gastroenteritis, the main cause of foodborne deaths. Currently, Campylobacter is a common foodborne pathogen found in poultry; thus, there is a need for the development of novel intervention strategies. The aim of the study was to examine the effect of eugenol on C. jejuni load in an experimental chicken meat model. We observed that eugenol was effective in reducing C. jejuni load for 7 days of storage. Eugenol treatment at all concentrations (1.28, 5.12, and 10.24 mg mL−1) decreased Campylobacter load more significantly in the reference strain, and this decrease was dose‐dependent throughout the storage period. Compared to the control group, eugenol reduced the counts of chicken isolate and the reference strain of C. jejuni by approximately 1.5 and 4.5 log/CFU, respectively, after 7 days of storage. Eugenol is a promising agent for improving the safety of poultry.

Campylobacter jejuni Surface-Bound Protease HtrA, but Not the Secreted Protease nor Protease in Shed Membrane Vesicles, Disrupts Epithelial Cell-to-Cell Junctions.

Fundamental functions of the intestinal epithelium include the digestion of food, absorption of nutrients, and its ability to act as the first barrier against intruding microbes. Campylobacter jejuni is a major zoonotic pathogen accounting for a substantial portion of bacterial foodborne illnesses. The germ colonizes the intestines of birds and is mainly transmitted to humans through the consumption of contaminated poultry meat. In the human gastrointestinal tract, the bacterium triggers campylobacteriosis that can progress to serious secondary disorders, including reactive arthritis, inflammatory bowel disease and Guillain-Barré syndrome. We recently discovered that C. jejuni serine protease HtrA disrupts intestinal epithelial barrier functions via cleavage of the tight and adherens junction components occludin, claudin-8 and E-cadherin. However, it is unknown whether epithelial damage is mediated by the secreted soluble enzyme, by HtrA contained in shed outer-membrane vesicles (OMVs) or by another mechanism that has yet to be identified. In the present study, we investigated whether soluble recombinant HtrA and/or purified OMVs induce junctional damage to polarized intestinal epithelial cells compared to live C. jejuni bacteria. By using electron and confocal immunofluorescence microscopy, we show that HtrA-expressing C. jejuni bacteria trigger efficient junctional cell damage, but not soluble purified HtrA or HtrA-containing OMVs, not even at high concentrations far exceeding physiological levels. Instead, we found that only bacteria with active protein biosynthesis effectively cleave junctional proteins, which is followed by paracellular transmigration of C. jejuni through the epithelial cell layer. These findings shed new light on the pathogenic activities of HtrA and virulence strategies of C. jejuni.

Impact of precursor-derived peracetic acid on post-weaning diarrhea, intestinal microbiota, and predicted microbial functional genes in weaned pigs

Post-weaning diarrhea affects piglets in the nursery phase of production, leading to a substantial impact both at the farm and financial levels. The multifactorial etiology of this disease includes housing conditions, pig genetics, microbial composition, and metagenomic assets. Among the common therapeutic approaches, the widely used zinc oxide underwent a European Union ban in 2022 due to its negative environmental impact and correlation to increased antimicrobial resistance. During this study, we have tested two levels of inclusion of the potential antimicrobial alternative peracetic acid, delivered in water via the hydrolysis of the precursors sodium percarbonate and tetraacetylethylenediamine, in comparison to zinc oxide and an untreated control during a 2-week animal study. We assessed the microbial composition and predicted the metagenome, together with performance and physiological parameters, in order to describe the microbial functional role in etiopathology. Both zinc oxide and peracetic acid resulted in amelioration of the diarrheal status by the end of the trial period, with noticeable zinc oxide effects visible from the first week. This was accompanied by improved performance when compared to the first-week figures and a decreased stomach pH in both peracetic acid levels. A significant reduction in both stomach and caecal Proteobacteria was recorded in the zinc oxide group, and a significant reduction of Campylobacter in the stomach was reported for both zinc oxide and one of the peracetic acid concentrations. Among other functional differences, we found that the predicted ortholog for the zonula occludens toxin, a virulence factor present in pathogens like Escherichia coli and Campylobacter jejuni, was less abundant in the stomach of treated pigs compared to the control group. In water, peracetic acid delivered via precursor hydrolysis has the potential to be a valid intervention, an alternative to antimicrobial, to assist the weaning of piglets. Our findings support the view that post-weaning diarrhea is a complex multifactorial disease with an important metagenomic component characterized by the differential abundance of specific predicted orthologs and microbial genera in the stomach and caecum of pigs.

Uridine Bisphosphonates Differentiate Phosphoglycosyl Transferase Superfamilies.

Complex bacterial glycoconjugates drive interactions between pathogens, symbionts, and their human hosts. Glycoconjugate biosynthesis is initiated at the membrane interface by phosphoglycosyl transferases (PGTs), which catalyze the transfer of a phosphosugar from a soluble uridine diphosphosugar (UDP-sugar) substrate to a membrane-bound polyprenol-phosphate (Pren-P). The two distinct superfamilies of PGT enzymes (polytopic and monotopic) show striking differences in their structure and mechanism. We designed and synthesized a series of uridine bisphosphonates (UBPs), wherein the diphosphate of the UDP and UDP-sugar is replaced by a substituted methylene bisphosphonate (CXY-BPs; X/Y = F/F, Cl/Cl, (S)-H/F, (R)-H/F, H/H, CH3/CH3). UBPs and UBPs incorporating an N-acetylglucosamine (GlcNAc) substituent at the β-phosphonate were evaluated as inhibitors of a polytopic PGT (WecA from Thermotoga maritima) and a monotopic PGT (PglC from Campylobacter jejuni). Although CHF-BP most closely mimics diphosphate with respect to its acid/base properties, the less basic CF2-BP conjugate more strongly inhibited PglC, whereas the more basic CH2-BP analogue was the strongest inhibitor of WecA. These surprising differences indicate different modes of ligand binding for the different PGT superfamilies, implicating a modified P-O- interaction with the structural Mg2+. For the monoPGT enzyme, the two diastereomeric CHF-BP conjugates, which feature a chiral center at the Pα-CHF-Pβ carbon, also exhibited strikingly different binding affinities and the inclusion of GlcNAc with the native α-anomer configuration significantly improved binding affinity. UBP-sugars are thus revealed as informative new mechanistic probes of PGTs that may aid development of novel antibiotic agents for the exclusively prokaryotic monoPGT superfamily.

Oral treatment of human gut microbiota associated IL-10-/- mice suffering from acute campylobacteriosis with carvacrol, deferoxamine, deoxycholic acid, and 2-fucosyl-lactose.

Food-borne Campylobacter jejuni infections constitute serious threats to human health worldwide. Since antibiotic treatment is usually not indicated in infected immune-competent patients, antibiotic-independent treatment approaches are needed to tackle campylobacteriosis. To address this, we orally applied carvacrol, deferoxamine, deoxycholate, and 2-fucosyl-lactose either alone or all in combination to human microbiota-associated IL-10-/- mice from day 2 until day 6 following oral C. jejuni infection. Neither treatment regimen affected C. jejuni loads in the colon, whereas carvacrol lowered the pathogen numbers in the ileum on day 6 post-infection (p.i.). The carvacrol and combination treatment regimens resulted in alleviated diarrheal symptoms, less distinct histopathological and apoptotic epithelial cell responses in the colon, as well as diminished numbers of colonic neutrophils and T lymphocytes on day 6 p.i., whereas the latter cells were also decreased upon deferoxamine, deoxycholate, or 2-fucosyl-lactose application. Remarkably, the carvacrol, deferoxamine, and combination treatment regimens dampened ex-vivo IFN-γ secretion in the colon, the kidneys, and even in the serum to basal concentrations on day 6 p.i. In conclusion, carvacrol alone and its combination with deferoxamine, deoxycholate, and 2-fucosyl-lactose constitute promising antibiotics-independent treatment options to fight acute campylobacteriosis.

P232 Common variable immunodeficiency-associated enteropathy in consecutive patients from a tertiary hospital

Abstract Background Common variable immunodeficiency (CVID) patients may develop intestinal inflammatory involvement in 9-20% of cases, although its diagnosis, management and prognosis are not well established. Methods We performed a transversal study with retrospective data collection. We reviewed all clinical records from consecutive adult CVID patients followed in Gregorio Marañón Hospital (Spain) from January 1st 1990 to January 1st 2023. A diagnosis of CVID-associated enteropathy (CVID-E) was established if patchy intestinal inflammation (Crohn-like pattern) or colonic inflammation (ulcerative colitis-like pattern) was demonstrated, or villous atrophy was observed in duodenal biopsies (celiac-like pattern) or inflammatory infiltrate was observed in colonic biopsies (microscopic colitis-like pattern). Differences between CVID-E patients and the rest of the CVID cohort were evaluated using chi-square and T student methods, when appropriate. Results 89 patients with confirmed CVID following ESID criteria were included. Patients’ characteristics are summarised in Table 1. All patients were receiving intravenous or subcutaneous Igs and reached an Ig G trough level >1000 mg/dL. CVID-E was diagnosed in 26 patients (29,2%), at a median of 6,4 years after CVID diagnosis. Surprisingly, 10 patients (38,5%) were diagnosed with CVID-E before or at the same time of CVID diagnosis. 5 patients were dead (19,2%), and the causes of death were gastric cancer (1 patient), liver complications (1), infectious complications (1), enteropathy (1) and unknown cause (1). 73,1% suffered from GI infections (Giardia lamblia, Campylobacter jejuni and Clostridioides difficile were the most frequent agents). The most frequent pattern of the disease was Crohn-like disease (Figure 1). Although exclusive celiac-like pattern was found in only 3 patients, 5 Crohn-like, 4 UC-like and 2 microscopic colitis-like pattern patients also presented duodenal atrophy. Unexpectedly, 46,2% of CVID-E patients suffered from concomitant liver involvement. Eight patients received corticosteroids, 2 azathioprine and 1 patient received infliximab and subsequent ustekinumab. One patient needed subtotal colectomy, another ileal resection and another patient received a terminal colostomy due to severe perianal disease. CVID-E patients presented statistically more frequent liver involvement, more GI infections, and a tendency towards more GI cancer. Conclusion CVID-E is frequent among CVID patients. These patients suffer from more GI infections, liver involvement and probably more GI cancer. Screening of levels of Igs at diagnosis of IBD and celiac disease is advisable as CVID diagnosis can occur at the same time or even after enteropathy diagnosis.

Inhibition of Food-Borne Pathogen Growth and Biogenic Amine Synthesis by Spice Extracts

Food-borne pathogens and their toxins cause significant health problems in humans. Formation of biogenic amines (BAs) produced by microbial decarboxylation of amino acids in food is undesirable because it can induce toxic effects in consumers. Therefore, it is crucial to investigate the effects of natural additives with high bioactivity like spice extracts to inhibit the growth of these bacteria and the formation of BAs in food. In the present study, the antibacterial effects of diethyl ether spice (sumac, cumin, black pepper, and red pepper) extracts at doses of 1% (w/v) on Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative (Klebsiella pneumoniae, Pseudomonas aeruginosa, Campylobacter jejuni, Aeromonas hydrophila, Salmonella Paratyphi A, and Yersinia enterocolitica) food-borne pathogen bacterial strains (FBP) were established. In addition, the accumulation of ammonia (AMN), trimethylamine (TMA), and biogenic amines (BAs) in tyrosine decarboxylase broth (TDB) was investigated by using high performance liquid chromatography (HPLC). Sumac extract exhibited the highest antibacterial potential against all FBPs, followed by cumin and peppers. AMN (570.71 mg/L) and TMA (53.66 mg/L) production were strongly inhibited by sumac extract in the levels of 55.10 mg/L for Y. enterocolitica and 2.76 mg/L for A. hydrophila, respectively. With the exception of S. aureus, black pepper dramatically reduced the synthesis of putrescine, serotonin, dopamine, and agmatine by FBP especially for Gram-negative ones. Furthermore, sumac extracts inhibited histamine and tyramine production by the majority of FBP. This research suggests the application of sumac extracts as natural preservatives for inhibiting the growth of FBPs and limiting the production of AMN, TMA, and BAs.

Prophylactic Oral Application of Activated Charcoal Mitigates Acute Campylobacteriosis in Human Gut Microbiota-Associated IL-10-/- Mice.

The incidence of human Campylobacter jejuni infections is increasing worldwide. It is highly desirable to prevent campylobacteriosis in individuals at risk for severe disease with antibiotics-independent non-toxic compounds. Activated charcoal (AC) has long been used as an anti-diarrheal remedy. Here, we tested the disease-mitigating effects of oral AC versus placebo in human gut microbiota-associated (hma) IL-10-/- mice starting a week prior to C. jejuni infection. On day 6 post-infection, the gastrointestinal C. jejuni loads were comparable in both infected cohorts, whereas campylobacteriosis symptoms such as wasting and bloody diarrhea were mitigated upon AC prophylaxis. Furthermore, AC application resulted in less pronounced C. jejuni-induced colonic epithelial cell apoptosis and in dampened innate and adaptive immune cell responses in the colon that were accompanied by basal concentrations of pro-inflammatory mediators including IL-6, TNF-α, IFN-γ, and nitric oxide measured in colonic explants from AC treated mice on day 6 post-infection. Furthermore, C. jejuni infection resulted in distinct fecal microbiota shift towards higher enterobacterial numbers and lower loads of obligate anaerobic species in hma mice that were AC-independent. In conclusion, our pre-clinical placebo-controlled intervention study provides evidence that prophylactic oral AC application mitigates acute murine campylobacteriosis.

Immunoinformatics-driven approach for development of potential multi-epitope vaccine against the secreted protein FlaC of Campylobacter jejuni

Campylobacter jejuni causes a leading human gastrointestinal infection which is associated with foodborne diarrhea, stomach cramping, and fever. In the recent years, numerous multidrug-resistant strains of C. jejuni has evolved and is considered in the priority pathogens category. Therefore, an increasing demand exists to develop an effective vaccine against Campylobacteriosis. The T cell and B cell epitopes from the FlaC protein were predicted using comprehensive immunoinformatics tools. The predicted epitopes were chosen based on their antigenicity, allergenicity, and toxicity profiles. Using the bioinformatics approach various physicochemical properties of the constructed vaccine were determined. The molecular docking analysis of the vaccine with the TLRs demonstrated that TLR5 has a higher binding affinity of −1159.0 kcal/mol. Molecular dynamics simulation has confirmed the stable association of the vaccine with TLR5. The immune response of the constructed vaccine was validated using immunostimulation. Based on this study, we recommend the formulation of a multi-epitope vaccine as a promising agent to effectively combat the dreadful campylobacteriosis infection. Communicated by Ramaswamy H. Sarma

Retracted: Inter-Relationship Between a Transcriptional Regulator of Flagella Genes cj0440c and Thiamine Metabolic Pathway in Campylobacter jejuni.

[This retracts the article DOI: 10.1155/2022/4539367.].

Campylobacter Species: New Insight, Clinical Diagnosis and Laboratory Approach

Campylobacter, a prevalent cause of global gastroenteritis, has exhibited an escalating impact worldwide, affecting both industrialized and developing nations. Even though Campylobacter jejuni and C. coli are the main causes of infection, new pathogens make it imperative to comprehend the disease mechanisms, dynamics of transmission, and evolution of less-studied species. Accessible whole-genome sequences obtained through high-throughput sequencing have made it easier to conduct in-depth pathogenomic studies, particularly on species such as C. fetus and C. concisus. These studies have shown novel applications in clinical microbiology by revealing genomic traits associated with pathogenicity and offering insights into the evolutionary mechanisms shaping their genomes. Effective pathogen management urgently requires deeper understanding of the evolution of pathogenicity in emerging Campylobacter species are urgently required for effective pathogen management. This comprehensive review synthesizes existing knowledge and outlines future research directions in this crucial field. The Gram-negative, non-spore-forming, curved or spiral rods known as campylobacters include a "thermophilic group" that is important to the water industry and includes C. jejuni, C. coli, and C. upsaliensis. Acute diarrhea is the usual symptom of a human Campylobacter infection, and key virulence factors have been identified as antibiotic resistance genes and flagellar DNA. Many campylobacters are frequently found in sewage and treated sewage effluents, whereas surface waters are less contaminated. Testing for Campylobacter prevalence through epidemiological methods requires a careful balance between phenotypic and genotypic data. Campylobacters are sensitive to oxygen, but they have strong survival strategies that may involve the formation of biofilms. Methods of inactivation that work well for coliforms are thought to be appropriate for Campylobacter. In addition to providing a synthesis of current knowledge and identifying future research directions to advance strategies for the effective management and mitigation of Campylobacter-related infections, this thorough review highlights the urgent need for additional research to deepen our understanding of these pathogens. The investigation of genetic features linked to pathogenicity, dynamics of transmission, and survival strategies highlights the complex character of Campylobacter infections. The dynamic nature of Campylobacter as a primary cause of gastroenteritis necessitates continued research endeavors to guide focused interventions and lessen the worldwide impact of this grave public health issue.

Prokaryotic and eukaryotic dual-expression plasmid-mediated delivery of Campylobacter jejuni antigens by live-attenuated Salmonella: A strategy for concurrent Th1 and Th2 immune activation and protection in chickens

Salmonella and Campylobacter are food-borne pathogens that significantly affect poultry production and are transmitted to humans. Long-term protection against these pathogens in chicken relies on a balanced Th1 and Th2 response. C. jejuni antigens were screened and a fusion antigen, including CadF + FlaA adhesin and flagellin antigenic fragments was developed and safely delivered by low-endotoxicity S. Typhimurium through pJHL270, a dual-expression plasmid featuring prokaryotic (Ptrc) and eukaryotic (CMV) promoters. Antigen expression in Salmonella and host cells was confirmed by western blotting and IFA. The vaccine construct JOL2999, triggered significant increases in IgY, IgA antibodies, CD4+ and CD8+ T cells, indicating humoral, mucosal, and cell-mediated responses against both pathogens. Elevations in pro-inflammatory cytokines TNFα, INF-γ, IL-2, and IL-4 and MHC I and II cell populations further suggest simultaneous Th1 and Th2 immune activation. Reduced pathogen load and histopathological inflammatory signs in vital organs upon challenge confirmed the protective efficacy in chickens.

Structural analysis of the YqeY proteins from Campylobacter jejuni and Vibrio parahaemolyticus

YqeY is a functionally and structurally uncharacterized protein that is ubiquitously expressed in bacteria. To gain structural insights into the function of YqeY, we determined the crystal structures of the Campylobacter jejuni and Vibrio parahaemolyticus YqeY proteins (cjYqeY and vpYqeY, respectively) and analyzed the structural and functional roles of conserved residues via a mutational study. Both cjYqeY and vpYqeY were found to adopt a two-domain structure consisting of an N-terminal four-α-helix domain and a C-terminal three-α-helix domain, with a relatively flexible interdomain orientation. The YqeY structure is unique in its linkage of the two α-helix domains although the C-terminal YqeY domain is structurally homologous to the terminal appendages of glutaminyl-tRNA synthetase and tRNA-dependent amidotransferase. We identified six conserved YqeY residues (Y67, R72, E82, Y89, P91, and G119) and evaluated their roles in protein stability via alanine mutation using a thermal shift assay. Residues Y67, R72, Y89, and P91 were shown to be required to maintain the structural integrity of YqeY. In contrast, residues E82 and G119 were not found to be essential for protein stability and are highly likely to contribute to the biological function of YqeY.

Identification of antimicrobial resistance profiles and antimicrobial resistance genes of Campylobacter isolates from broiler farms in Sri Lanka

Antimicrobial resistant (AMR) bacteria including Campylobacter has become an emerging global concern in human and animal health. There are very few researches on AMR Campylobacter conducted in Sri Lanka and none of them studied about AMR genes to the best of our knowledge. The present study focused on the detection of AMR Campylobacter from broiler in Sri Lanka, resistant against frequently used antimicrobials. Further, presence of AMR genes or mutations in responsible genes were compared to the resistant phenotypes. Cloacal swabs were collected from 118 broilers in nine farms covering three provinces in Sri Lanka. One Campylobacter colony per sample was isolated and the antimicrobial susceptibility test of the isolates was performed by inoculating the isolates onto agar plates with threshold concentrations of eight antimicrobial agents which belong to six antimicrobial classes. Three genetic markers for antimicrobial resistance, point mutations in 23S rRNA gene and gyrA gene, and the presence of resistant gene, tet(O) were also investigated. Altogether, 73 samples were Campylobacter positive of which 59 were Campylobacter jejuni, 13 were Campylobacter coli and one was unidentified Campylobacter. All isolates were resistant to three or more antimicrobials tested. The isolates were frequently resistant to ciprofloxacin, nalidixic acid, trimethoprim-sulfamethoxazole, amoxicillin and tetracycline, and susceptible to gentamicin and streptomycin, while the resistance to erythromycin was different between the species. Genetic screening revealed that most of the isolates possessed one or more of these genetic markers. This study urges the need of continuous surveillance for AMR Campylobacter in Sri Lanka.

Gut metabolite L-lactate supports Campylobacter jejuni population expansion during acute infection.

How the microaerobic pathogen Campylobacter jejuni establishes its niche and expands in the gut lumen during infection is poorly understood. Using 6-wk-old ferrets as a natural disease model, we examined this aspect of C. jejuni pathogenicity. Unlike mice, which require significant genetic or physiological manipulation to become colonized with C. jejuni, ferrets are readily infected without the need to disarm the immune system or alter the gut microbiota. Disease after C. jejuni infection in ferrets reflects closely how human C. jejuni infection proceeds. Rapid growth of C. jejuni and associated intestinal inflammation was observed within 2 to 3 d of infection. We observed pathophysiological changes that were noted by cryptic hyperplasia through the induction of tissue repair systems, accumulation of undifferentiated amplifying cells on the colon surface, and instability of HIF-1α in colonocytes, which indicated increased epithelial oxygenation. Metabolomic analysis demonstrated that lactate levels in colon content were elevated in infected animals. A C. jejuni mutant lacking lctP, which encodes an L-lactate transporter, was significantly decreased for colonization during infection. Lactate also influences adhesion and invasion by C. jejuni to a colon carcinoma cell line (HCT116). The oxygenation required for expression of lactate transporter (lctP) led to identification of a putative thiol-based redox switch regulator (LctR) that may repress lctP transcription under anaerobic conditions. Our work provides better insights into the pathogenicity of C. jejuni.

Effect of biofilm formation in a hostile oxidative stress environment on the survival of Campylobacter jejuni recovered from poultry in Iraqi markets.

Campylobacter jejuni is a major contributor to bacterial enteritis, a common health problem. The resistance of this microaerophilic bacterium to oxidative stress allows it to thrive under aerobic conditions. This study aimed to investigate whether the capacity of C. jejuni to form biofilms in the presence of oxidative stress contributes to the pathogen's ability to thrive in agricultural settings as well as in chicken slaughter lines. Twenty identified strains originating from chicken samples (eight from caeca contents and 12 from frozen chicken carcasses) were previously isolated and identified according to standard bacteriological protocols, followed by confirmation at the species level using multiplex polymerase chain reaction assay. Crystal violet staining was used to evaluate biofilm formation by these bacteria. Two exposure periods to gaseous ozone (1 and 2 min) were used to assess resistance to oxidative damage. Most of the strong biofilm-forming Campylobacter strains came from imported frozen chicken meat (25%), whereas only 10% came from caeca content. After exposure to gaseous ozone at 600 mg/h for 2 min, strong biofilm-producing strains exhibited a higher survival rate with a limited reduction of up to 3 logs, whereas negative biofilm-producing strains exhibited a limited survival rate with a reduction of 6 logs. Based on our findings, we hypothesized that the presence of C. jejuni strains capable of forming biofilms in poultry farms and/or chicken production facilities triggers a public health alarm as this bacterium seems to be able to adapt more easily to live and thrive in hostile environmental conditions.

Clinico-bacteriological Study and Molecular Detection of Campylobacter in Childhood Diarrhoea: A Cross-sectional Study

Introduction: Campylobacter infections cause diarrhoeal diseases as frequently as Salmonella and Shigella infections. The prevalence of Campylobacter infection among children with acute diarrhoea in developing countries ranges from 5-35%. Diagnosing Campylobacter infections is challenging as the organism is difficult to isolate, grow, and identify. Currently, no best-practice clinical or public health laboratory guidelines exist for laboratory diagnosis of Campylobacter infections. Aim: To explore the clinical and bacterial aspects of childhood diarrhoea, emphasising the prevalence and molecular detection of Campylobacter. Materials and Methods: A hospital-based cross-sectional descriptive study was conducted with 55 stool samples of children under five with diarrhoea or dysentery at the Department of Microbiology, JSS Medical College, Mysuru, Karnataka, India, from October 2016 to September 2017. All stool samples were inoculated onto Campylobacter selective and non selective media with filtration and incubated in microaerophilic conditions. The culture isolates were identified by standard phenotypic tests. Molecular characterisation of Campylobacter was performed targeting the Campylobacter adhesion to fibronectin F (cadF) gene. The presence of a phylogenetically conserved 16S ribosomal Ribonucleic Acid (16SrRNA) domain was studied, followed by specific detection of pathogenic Campylobacter species. The Statistical Package for Social Sciences (SPSS) version 22.0 was used for statistical analysis. Descriptive statistics like percentage, mean, and Standard Deviation (SD) were applied. Results: Campylobacter was isolated by culture in one out of 55 stool samples. The isolate was confirmed to be Campylobacter jejuni by phenotypic tests. Campylobacter genus-level Polymerase Chain Reaction (PCR) was positive for 6 samples (10.9%). Six positive samples were subjected to species-level PCR; all were positive for C. jejuni. Out of 55 stool samples, two diarrheagenic Escherichia coli, two Shigella sonnei, one Shigella dysenteriae, and one Salmonella enterica serovar Typhi were also identified. Conclusion: Culture is insufficiently sensitive for diagnosing Campylobacter infection compared with nucleic acid-based diagnostics. Nucleic acid-based diagnostics offer increased sensitivity, can determine both the presence and burden of infection, and can distinguish between Campylobacter infections at the species level. Therefore, PCR is recommended, if feasible, as the preferred diagnostic modality for detecting Campylobacter infection.

Purpose-built multicomponent supramolecular silver(I)-hydrogels as membrane-targeting broad-spectrum antibacterial agents against multidrug-resistant pathogens.

Membrane-targeting compounds are of immense interest to counter complicated multi-drug resistant infections. However, the broad-spectrum effect of such compounds is often unmet due to the surges of antibiotic resistance among majority of Gram-negative bacteria compared to Gram-positive species. Though amphiphiles, synthetic mimics of antimicrobial peptides etc, have been extensively explored for their potential to perturb bacterial membranes, small molecule-based supramolecular hydrogels have remained unexplored. The design of supramolecular hydrogels can be tuned on-demand, catering to desired applications, including facile bacterial membrane perturbation. Considering the strong biocidal properties of Ag-based systems and the bacterial membrane-targeting potential of appended primary amine groups, we designed self-assembled multicomponent supramolecular Ag(I)-hydrogels with urea and DATr (3,5-diamino-1,2,4-triazole) as ligands, which are predisposed for hydrogen bonding and interacting with negatively charged bacterial membranes at physiological pH. The synthesized supramolecular Ag(I)-hydrogels exhibited almost similar antibacterial activity against both Gram-negative (Campylobacter jejuni; C. jejuni) and Gram-positive (Staphylococcus aureus; S. aureus) bacteria, with minimal inhibitory concentration (MIC) of ∼60 μg mL-1. Ag(I)-hydrogels facilitated the disruption of the negatively charged bacterial membrane due to electrostatic interaction and complementary hydrogen bonding facilitated by DATr and urea. Sustained intracellular ROS generation in the presence of Ag(I)-hydrogel further expedited cell lysis. We envisage that the multicomponent supramolecular Ag(I)-hydrogels studied herein can be employed in designing effective antibacterial coatings on a range of medical devices, including surgical instruments. Moreover, the present form of the hydrogels has the potential to improve the antibacterial functionality of conventional antimicrobials, thus revitalizing the effective targeting of hard-to-treat multi-drug-resistant (MDR) bacterial infections in a clinical set up.

Reduction of Campylobacter jejuni contamination by using UVA-LED and sodium hypochlorite on the surface of chicken meat.

Campylobacter jejuni causes gastroenteritis in humans and is a major concern in food safety. Commercially prepared chicken meats are frequently contaminated with C. jejuni, which is closely associated with the diffusion of intestinal contents in poultry processing plants. Sodium hypochlorite (NaClO) is commonly used during chicken processing to prevent food poisoning; however, its antimicrobial activity is not effective in the organic-rich solutions. In this study, we investigated the potential of a new photo-disinfection system, UVA-LED, for the disinfection of C. jejuni-contaminated chicken surfaces. The data indicated that UVA irradiation significantly killed C. jejuni and that its killing ability was significantly facilitated in NaClO-treated chickens. Effective inactivation of C. jejuni was achieved using a combination of UVA and NaClO, even in the organic-rich condition. The results of this study show that synergistic disinfection using a combination of UVA and NaClO has potential beneficial effects in chicken processing systems.

A ten-year review of antimicrobial resistance among human Campylobacter jejuni isolates

Campylobacter jejuni is a major pathogen responsible for a significant number of reported campylobacteriosis cases in the European Union. Due to underdiagnosed and underreported cases, there are no existing studies on this pathogen. Fluoroquinolones have been the primary treatment for campylobacteriosis for many years. Fluoroquinolone resistance is causing an increase, which means that a new class of antibiotics must be introduced. The treatment of campylobacteriosis is currently based on macrolides, but with the increasing rates of resistance, active surveillance for antibiotic resistance is required. The aim of this study was to track the increasing prevalence of AMR in clinical isolates of C. jejuni across Bulgaria for a period of 10 years.