Campylobacter jejuni is a prevalent gastrointestinal pathogen in humans and a common commensal of poultry. When colonizing its hosts, C. jejuni comes into contact with intestinal carbohydrates, ...including L-fucose, released from mucin glycoproteins. Several strains of jejuni possess a genomic island (cj0480c-cj0490) that is up-regulated in the presence of both L-fucose and mucin and allows for the utilization of L-fucose as a substrate for growth. Strains possessing this genomic island show increased growth in the presence of L-fucose and mutation of cj0481, cj0486, and cj0487 results in the loss of the ability to grow on this substrate. Furthermore, mutants in the putative fucose permease (cj0486) are deficient in fucose uptake and demonstrate a competitive disadvantage when colonizing the piglet model of human disease, which is not paralleled in the colonization of poultry. This identifies a previously unrecorded metabolic pathway in select strains of C. jejuni associated with a virulent lifestyle.
Campylobacter jejuni cells have bipolar flagella. Both flagella have similar lengths of about one helical turn, or 3.53±0.52 µm. The flagellar filament is composed of two homologous flagellins: FlaA ...and FlaB. Mutant strains that express either FlaA or FlaB alone produce filaments that are shorter than those of the wild-type. It is reported that the flaG gene could affect filament length in some species of bacteria, but its function remains unknown. We introduced a flaG-deletion mutation into the C. jejuni wild-type strain and flaA- or flaB-deletion mutant strains, and observed their flagella by microscopy. The ΔflaG mutant cells produced long filaments of two helical turns in the wild-type background. The ΔflaAG double mutant cells produced very short FlaB filaments. On the other hand, ΔflaBG double mutant cells produced long FlaA filaments and their morphology was not helical but straight. Furthermore, FlaG was secreted, and a pulldown assay showed that sigma factor 28 was co-precipitated with purified polyhistidine-tagged FlaG. We conclude that FlaG controls flagella length by negatively regulating FlaA filament assembly and discuss the role of FlaA and FlaB flagellins in C. jejuni flagella formation.
•A new fluorescence immunosensor for detection Campylobacter jejuni was designed.•Specific binding of GQDs with campylobacter jejuni leads to fluorescence is ON.•The method was applied to analysis ...bacterial cell in poultry liver samples.
In this work a new fluorescence immunosensor with use of graphene oxide and graphene quantum dot for detection Campylobacter jejuni whole cell in food samples was designed. This biosensor was designed based on interaction of poly clonal antibody conjugated with graphene quantum dot with surface protein in Campylobacter jejuni cell membrane. Specific binding of graphene quantum dot with Campylobacter jejuni membrane leads to generate a distance among graphene dot and graphene oxide and fluorescence is ON. In lack of Campylobacter jejuni or in existence of other bacterial cells, distance between of graphene dot and graphene oxide is very low and graphene quantum dot fluorescence emission was OFF. Experiment revealed that step by step increase in bacterial target cells caused to gradually increased fluorescence emission and this process was linear. Limit of detection for this bacterial sensor was 10 CFU/ml and ability of this FRET immunosensor for Campylobacter jejuni sensing in comparison with other bacterial cells was significant. Also, this method for monitoring Campylobacter jejuni in poultry liver was applied and results revealed that this immunosensor could be used for analysis bacterial cell in food samples.
Aims
To define anti‐Campylobacter jejuni activity of an extract from waste skins and seeds of Pinot noir grapes (GSS), resveratrol and possible resistance mechanisms, and the influence of these on ...Camp. jejuni morphology.
Methods and Results
Using gene‐specific knock‐out Camp. jejuni mutants and an efflux pump inhibitor, we showed CmeABC as the most active efflux pump for extrusion across the outer membrane of GSS extract and resveratrol. Using polystyrene surface and pig small intestine epithelial (PSI) and human foetal small intestine (H4) cell lines, GSS extract shows an efficient inhibition of adhesion of Camp. jejuni to these abiotic and biotic surfaces.
Conclusions
Low doses of GSS extract can inhibit Camp. jejuni adhesion to polystyrene surfaces and to PSI and H4 cells, and can thus modulate Camp. jejuni invasion and intracellular survival.
Significance and Impact of the Study
An understanding of the activities of GSS extract and resveratrol as bacterial growth inhibitors and the specific mechanisms of cell accumulation is crucial for our understanding of Camp. jejuni resistance. GSS extract inhibition of Camp. jejuni adhesion to abiotic and biotic surfaces provides a further step towards the application of new innovative strategies to control Campylobacter contamination and infection via the food chain.
Campylobacter jejuni is a leading cause of foodborne illness in industrialized countries. This pathogen exhibits significant strain-to-strain variability, which results in differences in virulence ...potential and clinical presentations. Here, we report that acquisition of the capacity to utilize specific nutrients enhanced the ability of a highly pathogenic strain of C. jejuni to colonize specific tissues. The acquisition of a gene encoding a gamma-glutamyltranspeptidase enabled this strain to utilize glutamine and glutathione and enhanced its ability to colonize the intestine. Furthermore, the acquisition of a DNA segment, which added a sec-dependent secretion signal to an otherwise cytoplasmic asparaginase, allowed this pathogen to utilize asparagine and to more efficiently colonize the liver. Our results reveal that subtle genetic changes in a bacterial pathogen result in significant changes in its ability to colonize specific tissues. In addition, these studies revealed remarkably specific nutritional requirements for a pathogen to effectively colonize different tissues.
Herein, a high-affinity single-stranded DNA aptamer (59 nt) against
, defined as CJA1, was obtained using the whole-bacterium-based systemic evolution of ligands by exponential enrichment procedure. ...CJA1 was analyzed with a stable secondary structure and low dissociation constant (
) value of 1.37 ± 0.28 nM. The potential use of CJA1 was exemplified by the construction of a hetero-sandwich platform, in which
was bound with a biotin-tagged CJA1 to perform a colorimetric reaction that is associated with visible color changes and detectable optical responses. Dependent upon this sensing platform,
can be detected from 1.7 × 10
to 1.7 × 10
colony-forming units (CFU)/mL. The limit of detection (LOD) is obtained as 10 CFU/mL in PBS. The specificity study showed that the sensing platform is easy to distinguish
from other common pathogens. Moreover, the
-contaminated milk samples can also be accurately probed (LOD = 13 CFU/mL) without sacrificing its assay abilities, indicating the promising prospect of CJA1 in the fields of biosensing and diagnostics.
Antimicrobial resistance was evaluated in Campylobacter jejuni isolated from 1291 diarrheic people over a 15-year period (2004–2018) in southwestern Alberta, a model location in Canada with a high ...rate of campylobacteriosis. The prevalence of resistance to chloramphenicol, clindamycin, erythromycin, and gentamicin was low during the examination period (≤4.8%). Resistance to tetracycline remained consistently high (41.6%–65.1%), and resistance was primarily conferred by plasmid-borne tetO (96.2%). Resistance rates to ciprofloxacin and nalidixic acid increased substantially over the examination period, with a maximal fluoroquinolone resistance (FQR) prevalence of 28.9% in 2016. The majority of C. jejuni isolates resistant to ciprofloxacin (93.9%) contained a C257T single nucleotide polymorphism within the gyrA chromosomal gene. Follow up with infected people indicated that the observed increase in FQR was primarily due to domestically acquired infections. Moreover, the majority of FQ-resistant C. jejuni subtypes (82.6%) were endemic in Canada, primarily linked to cattle and chicken reservoirs; 18.4% of FQ-resistant isolates were assigned to three subtypes, predominantly associated with cattle. Study findings indicate the need to prioritize FQR monitoring in C. jejuni infections in Canada and to elucidate the dynamics of the emergence and transmission of resistant C. jejuni strains within and from cattle and chicken reservoirs.
Investigations into bacterial protein glycosylation continue to progress rapidly. It is now established that bacteria possess both N-linked and O-linked glycosylation pathways that display many ...commonalities with their eukaryotic and archaeal counterparts as well as some unexpected variations. In bacteria, protein glycosylation is not restricted to pathogens but also exists in commensal organisms such as certain Bacteroides species, and both the N-linked and O-linked glycosylation pathways can modify multiple proteins. Improving our understanding of the intricacies of bacterial protein glycosylation systems should lead to new opportunities to manipulate these pathways in order to engineer glycoproteins with potential value as novel vaccines.
Campylobacter jejuni is a leading food-borne pathogen, and its antibiotic resistance is of serious concern to public health worldwide. C. jejuni is naturally competent for DNA transformation and ...freely takes up foreign DNA harboring genetic information responsible for antibiotic resistance. In this study, we demonstrate that C. jejuni transfers antibiotic resistance genes more frequently in biofilms than in planktonic cells by natural transformation.
A total of 95 human Campylobacter jejuni isolates acquired from domestic infections and collected from three districts in Finland during the seasonal peak (June to September) in 2012 were analyzed by ...PCR-based multilocus sequence typing (MLST) and by whole-genome sequencing (WGS). Four predominant sequence types (STs) were detected among the isolates: ST-45 (21%) and ST-230 (14%, ST-45 clonal complex CC), ST-267 (21%, ST-283 CC), and ST-677 (19%, ST-677 CC). In districts 1 and 3, most of the infections occurred from early July to the middle of August, with a peak at weeks 29 to 31, but in district 2, the infections were dispersed more evenly throughout 3 months (June to August). WGS data were used for further whole-genome MLST (wgMLST) analyses of the isolates representing the four common STs. Shared loci of the isolates within each ST were analyzed as distance matrices of allelic profiles by the neighbor-net algorithm. The highest allelic variations (>400 different alleles) were detected between different clusters of ST-45 isolates (1,121 shared loci), while ST-230 (1,264 shared loci), ST-677 (1,169 shared loci), and ST-267 isolates (1,217 shared loci) were less diverse with the clusters differing by <40 alleles. Closely related isolates showing no allelic variation (subclusters) were detected among all four major STs. In some cases, they originated from different districts, suggesting that isolates can be epidemiologically connected and may have the same infection source despite being originally identified as sporadic infections.
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