A case-case comparison of Campylobacter coli and Campylobacter jejuni infection: a tool for generating hypotheses

A single nucleotide polymorphism produces different transcription profiles in Campylobacter jejuni's cysM

A single nucleotide polymorphism (SNP) in the 126 bp untranslated region (UTR) directly upstream of Campylobacter jejuni's cysM (cysteine synthase) results in significant effects on gene transcription. UTR sequences, containing the predicted promoter region of cysM, from 264 different strains were compared, and revealed a SNP twenty nucleotides upstream of the cysM translation start site. In 219 strains the UTR sequence contained a guanine at this locus, and the remaining 45 strains had an adenine at the same position. Strains possessing the guanine SNP showed higher amounts of cysM transcripts compared to adenine SNP strains. When both UTR regions were cloned upstream of the major flagellar subunit (flaA) the guanine SNP UTR resulted in significantly greater levels of flaA transcription compared to the adenine SNP containing UTR. Additionally, when the UTR containing the guanine SNP was fused to flaA, motility was restored for a flaAB null mutant. Motility was not rescued initially when flaA was fused to the UTR containing the adenine SNP UTR. However, when the flaAB null mutant, containing a copy of flaA fused to the adenine-containing UTR, was incubated in Brucella broth for a minimum of two consecutive passages each lasting 48 h, transcription of flaA increased and motility was restored. Additional analysis of the flaA mRNA produced by the strain containing the adenine SNP UTR fused to flaA grown in Brucella broth versus agar suggests that the effects on motility occurred through blocking of full-length mRNA production.

WQ-3810, a fluoroquinolone with difluoropyridine derivative as the R1 group exerts high potency against quinolone-resistant Campylobacter jejuni

Quinolone-resistant Campylobacter jejuni have been increasing worldwide. Quinolones exert their antibacterial activity by inhibiting DNA gyrase, but most of the isolates acquire quinolone resistance via an amino acid substitution in the A subunit of DNA gyrase. WQ-3810 is a quinolone antibiotic that has been reported to have high potency even to DNA gyrase with amino acid substitutions in several bacterial species; however, there was no information on C. jejuni. Hence, this study aimed to evaluate the activity of WQ-3810 to inhibit wild-type/mutant DNA gyrases of C. jejuni and the bacterial growth for accessing the potency for the treatment of quinolone-resistant C. jejuni infection. The inhibitory activity of WQ-3810 was assessed and compared with ciprofloxacin and nalidixic acid by calculating the half maximal inhibitory concentration (IC50) against wild-type/mutant DNA gyrases. Next, the minimum inhibitory concentration (MIC) of WQ-3810 and five other quinolones was determined for C. jejuni including quinolone-resistant strains with amino acid substitutions in GyrA. Furthermore, the interaction between WQ-3810 and wild-type/mutant DNA gyrase was speculated using docking simulations. The IC50 of WQ-3810 against wild-type DNA gyrase was 1.03 µg/mL and not different from that of ciprofloxacin. However, those of WQ-3810 against mutant DNA gyrases were much lower than ciprofloxacin. The MICs of WQ-3810 ranged <0.016-0.031 µg/mL and were the lowest against both quinolone-susceptible and quinolone-resistant strains among the examined quinolones. The results obtained by the docking simulation agreed well with this observation. WQ-3810 seems to be a promising antimicrobial agent for the infections caused by quinolone-resistant C. jejuni.

IMPORTANCE

WQ-3810, a relatively new quinolone antibiotic, demonstrates exceptional antibacterial properties against certain pathogens in previous studies. However, its efficacy against quinolone-resistant Campylobacter jejuni was not previously reported. The prevalence of quinolone-resistant C. jejuni as a cause of foodborne illnesses is increasing, prompting this investigation into the effectiveness of WQ-3810 as a countermeasure. This study revealed high inhibitory activity of WQ-3810 against both wild-type and mutant DNA gyrases of C. jejuni. WQ-3810 was equally efficacious as ciprofloxacin against wild-type DNA gyrases but showed superior effectiveness against mutant DNA gyrases. WQ-3810 also demonstrated the lowest minimum inhibitory concentrations, highlighting its enhanced potency against both susceptible and resistant strains of C. jejuni. This observation was well supported by the results of the in silico analysis. Consequently, WQ-3810 exhibits a higher level of bactericidal activity compared to existing quinolones in combating both susceptible and resistant C. jejuni isolates.

Butyrate decreases Campylobacter jejuni motility and biofilm partially through influence on LysR expression

The food pathogen Campylobacter jejuni both colonizes the lower intestines of poultry and infects the lower intestines of humans. The lower intestines of both poultry and humans are also home to a wide range of commensal organisms which compete with an organism like C. jejuni for space and resources. The commensal organisms are believed to protect humans against infection by pathogens of the digestive tract like C. jejuni. The short chain fatty acid (SCFA) butyrate is a metabolite commonly produced by commensal organisms within both the poultry and human digestive tract. We investigated the effect that physiologically relevant concentrations of butyrate have on C. jejuni under in vitro conditions. Butyrate at concentrations of 5 and 20 mM negatively impacted C. jejuni motility and biofilm formation. These two traits are believed important for C. jejuni's ability to infect the lower intestines of humans. Additionally, 20 mM butyrate concentrations were observed to influence the expression of a range of different Campylobacter proteins. Constitutive expression of one of these proteins, LysR, within a C. jejuni strain partially lessened the negative influence butyrate had on the bacteria's motility.

Porcine carcasses as an underestimated source of antimicrobial resistant Campylobacter coli

Introduction

Campylobacteriosis is the most common human foodborne bacterial infection worldwide and is caused by bacteria of the Camplylobacter genus. The main source of these bacteria is poultry, but other food-producing animals such as pigs are also responsible for human infections. An increasing number of strains with resistance to fluoroquinolones and other antimicrobials such as macrolides were recently noted. The aim of the study was to investigate Campylobacter contamination of porcine carcasses and determine the antimicrobial resistance of the obtained isolates.

Material and Methods

A total of 534 swabs from carcasses of pigs slaughtered in Poland during 2019-2022 were tested for Campylobacter spp.

Results

Campylobacter was detected in 164 (30.7%) carcasses; among them 149 (90.8%) were classified as C. coli and the remaining 15 (9.2%) samples were C. jejuni-positive. Because a low number of C. jejuni isolates were identified, only the C. coli isolates were subjected to antimicrobial resistance analysis. The majority of these isolates were resistant to streptomycin (94.0%), ciprofloxacin (65.8%) and tetracycline (65.1%). A total of 94 (63.1%) strains displayed antimicrobial multiresistance patterns and were mainly resistant to fluoroquinolones, aminoglycosides and tetracyclines (74; 49.7% of the isolates tested).

Conclusion

The obtained results showed that pig carcasses may be contaminated with antimicrobial-resistant C. coli.

Antimicrobial Resistance of Campylobacter coli Isolated from Caecal Samples of Fattening Pigs at Slaughter

Pigs are known as the main Campylobacter coli reservoirs. Campylobacteriosis, the most commonly reported gastrointestinal disease in humans, is mainly caused by the consumption of poultry meat, and little is known about the role of pork. Pigs are often associated with C. coli, including antimicrobial-resistant isolates. Therefore, the entire pork production chain must be considered as an important source of antimicrobial-resistant C. coli. This study aimed to determine the antimicrobial resistance of Campylobacter spp. isolated from caecal samples of fattening pigs at the Estonian slaughterhouse level over a five-year period. The proportion of Campylobacter-positive caecal samples was 52%. All Campylobacter isolates were identified as C. coli. A high proportion of the isolates were resistant to most of the studied antimicrobials. The resistance to streptomycin, tetracycline, ciprofloxacin and nalidixic acid was 74.8%, 54.4%, 34.4% and 31.9%, respectively. In addition, a high proportion (15.1%) of the isolates were multidrug-resistant and, in total, 93.3% were resistant to at least one antimicrobial.

Diagnostic performance of microscopic stool examination in Campylobacter infection performed by different medical specialties

Background

Microscopic examination of stool samples can contribute to the early diagnosis of Campylobacter gastroenteritis. However, it is unclear whether the diagnostic performance is reliable when performed by physicians.

Methods

This prospective study included fresh stool samples collected from patients with gastroenteritis between August 2018 and March 2020. The samples were used for microscopic examination through Gram staining. Two physicians, a clinical laboratory technician, and microbiologists performed the examinations. In addition, antigen tests (QuickNavi-Campylobacter; Denka Co., Ltd.) were evaluated for the samples collected between May 2019 and March 2020. Infection with Campylobacter spp. was confirmed when stool cultures or polymerase chain reaction tests provided positive results.

Results

Microscopic examination was performed on 205 samples, of which 46 (22.4%) were positive for Campylobacter spp. For the microscopic examination, the sensitivity and specificity were 53.5% and 98.1% for physician A, 46.7% and 96.2% for physician B, 63.0% and 100% for the clinical laboratory technician, and 67.4% and 100% for microbiologists, respectively. The antigen testing was evaluated in 131 of the 205 samples and showed a sensitivity of 93.3% and specificity of 99.0%.

Conclusions

Microscopic examination of the stool samples showed high specificity. The sensitivity when the examinations were performed by the physicians was insufficient. The rapid antigen tests can reliably detect Campylobacter spp. in stool samples.

Effects of temperature on intestinal microbiota and lipid metabolism in Rana chensinensis tadpoles

Climate change such as global warming is considered a major threat to amphibians. The guts of amphibians are home to trillions of microbes, which are key regulators of gastrointestinal digestion and play a crucial role in lipid metabolites. The aim of this study was to evaluate the effect of temperature change on intestinal microbiota and lipid metabolism in Rana chensinensis tadpoles. Morphological and intestinal microbiota data of R. chensinensis larvae exposed to different temperatures (15 °C, 21 °C, and 26 °C) were measured. The results show that the warm temperature causes histological damage to the intestinal epithelium. In addition, temperature treatments alter the diversity and composition of gut microbes in R. chensinensis tadpoles. At the phylum level of intestinal microbial community, Campilobacterota was detected only in the warm group. At the genera level, unclassified_f__Enterobacteriaceae was markedly declined in the warm group but was notably enriched in the cold group. For lipid metabolism-related genes, the expression levels of GPR109A, HDAC1, and APOA-I decreased significantly in both warm and cold treatment groups, while the expression levels of CLPS and LIPASE increased significantly. Collectively, these observations demonstrated that warm and cold temperatures may reduce the immune capacity of tadpoles by changing the composition of intestinal microorganisms and the expression of genes related to lipid metabolism, affecting the survival of tadpoles.

Campylobacter in aquatic and terrestrial mammals is driven by life traits: A systematic review and meta-analysis

Introduction

Campylobacter spp. infections are responsible for significant diarrheal disease burden across the globe, with prevalence thought to be increasing. Although wild avian species have been studied as reservoirs of Campylobacter spp., our understanding of the role of wild mammalian species in disease transmission and persistence is limited. Host factors influencing infection dynamics in wild mammals have been neglected, particularly life traits, and the role of these factors in zoonotic spillover risk is largely unknown.

Methods

Here, we conducted a systematic literature review, identifying mammalian species that had been tested for Campylobacter spp. infections (molecular and culture based). We used logistic regression to evaluate the relationship between the detection of Campylobacter spp. in feces and host life traits (urban association, trophic level, and sociality).

Results

Our analysis suggest that C. jejuni transmission is associated with urban living and trophic level. The probability of carriage was highest in urban-associated species (p = 0.02793) and the most informative model included trophic level. In contrast, C. coli carriage appears to be strongly influenced by sociality (p = 0.0113) with trophic level still being important. Detection of Campylobacter organisms at the genus level, however, was only associated with trophic level (p = 0.0156), highlighting the importance of this trait in exposure dynamics across host and Campylobacter pathogen systems.

Discussion

While many challenges remain in the detection and characterization of Camploybacter spp., these results suggest that host life traits may have important influence on pathogen exposure and transmission dynamics, providing a useful starting point for more directed surveillance approaches.

Campylobacter jejuni and Campylobacter coli from Houseflies in Commercial Turkey Farms Are Frequently Resistant to Multiple Antimicrobials and Exhibit Pronounced Genotypic Diversity

Campylobacter is a leading foodborne pathogen, and poultry are a major vehicle for infection. Houseflies play important roles in colonization of broiler flocks with Campylobacter but comparable information for turkey farms is limited. Here, we investigated houseflies as potential vectors for Campylobacter in 28 commercial turkey flocks. We characterized species, genotypes, and the antimicrobial resistance (AMR) profiles of Campylobacter from turkey feces and houseflies in the same turkey house. Of the 28 flocks, 25 yielded Campylobacter from turkey droppings and houseflies, with an average of 6.25 and 3.11 Campylobacter log CFU/g feces and log CFU/fly, respectively. Three flocks were negative for Campylobacter both in turkey feces and in houseflies. Both C. coli and C. jejuni were detected in turkey feces and houseflies, with C. coli more likely to be recovered from houseflies than feces. Determination of Campylobacter species, genotypes, and AMR profiles revealed up to six different strains in houseflies from a single house, including multidrug-resistant strains. For the predominant strain types, presence in houseflies was predictive of presence in feces, and vice versa. These findings suggest that houseflies may serve as vehicles for dissemination of Campylobacter, including multidrug-resistant strains, within a turkey house, and potentially between different turkey houses and farms in the same region.

Genomic Insights into the Increased Occurrence of Campylobacteriosis Caused by Antimicrobial-Resistant Campylobacter coli

Campylobacter is the leading bacterial cause of diarrheal illnesses worldwide. Campylobacter jejuni and C. coli are the most common species accounting for campylobacteriosis. Although the proportion of campylobacteriosis caused by C. coli is increasing rapidly in China, the underlying mechanisms of this emergence remain unclear. In this study, we analyzed the whole-genome sequences and associated environments of 1,195 C. coli isolates with human, poultry, or porcine origins from 1980 to 2021. C. coli isolates of human origin were closely related to those from poultry, suggesting that poultry was the main source of C. coli infection in humans. Analysis of antimicrobial resistance determinants indicated that the prevalence of multidrug-resistant C. coli has increased dramatically since the 2010s, coinciding with the shift in abundance from C. jejuni to C. coli in Chinese poultry. Compared with C. jejuni, drug-resistant C. coli strains were better adapted and showed increased proliferation in the poultry production environment, where multiple antimicrobial agents were frequently used. This study provides an empirical basis for the molecular mechanisms that have enabled C. coli to become the dominant Campylobacter species in poultry; we also emphasize the importance of poultry products as sources of campylobacteriosis caused by C. coli in human patients. IMPORTANCE The proportion of campylobacteriosis caused by C. coli is increasing rapidly in China. Coincidentally, the dominant species of Campylobacter occurring in poultry products has shifted from C. jejuni to C. coli. Here, we analyzed the whole-genome sequences of 1,195 C. coli isolates from different origins. The phylogenetic relationship among C. coli isolates suggests that poultry was the main source of C. coli infection in humans. Further analysis indicated that antimicrobial resistance in C. coli strains has increased dramatically since the 2010s, which could facilitate their adaptation in the poultry production environment, where multiple antimicrobial agents are frequently used. Thus, our findings suggest that the judicious use of antimicrobial agents could mitigate the emergence of multidrug-resistant C. coli strains and enhance clinical outcomes by restoring drug sensitivity in Campylobacter.

Risk factors for campylobacteriosis in Australia: outcomes of a 2018-2019 case-control study

BACKGROUND

We aimed to identify risk factors for sporadic campylobacteriosis in Australia, and to compare these for Campylobacter jejuni and Campylobacter coli infections.

METHODS

In a multi-jurisdictional case-control study, we recruited culture-confirmed cases of campylobacteriosis reported to state and territory health departments from February 2018 through October 2019. We recruited controls from notified influenza cases in the previous 12 months that were frequency matched to cases by age group, sex, and location. Campylobacter isolates were confirmed to species level by public health laboratories using molecular methods. We conducted backward stepwise multivariable logistic regression to identify significant risk factors.

RESULTS

We recruited 571 cases of campylobacteriosis (422 C. jejuni and 84 C. coli) and 586 controls. Important risk factors for campylobacteriosis included eating undercooked chicken (adjusted odds ratio [aOR] 70, 95% CI 13-1296) or cooked chicken (aOR 1.7, 95% CI 1.1-2.8), owning a pet dog aged < 6 months (aOR 6.4, 95% CI 3.4-12), and the regular use of proton-pump inhibitors in the 4 weeks prior to illness (aOR 2.8, 95% CI 1.9-4.3). Risk factors remained similar when analysed specifically for C. jejuni infection. Unique risks for C. coli infection included eating chicken pâté (aOR 6.1, 95% CI 1.5-25) and delicatessen meats (aOR 1.8, 95% CI 1.0-3.3). Eating any chicken carried a high population attributable fraction for campylobacteriosis of 42% (95% CI 13-68), while the attributable fraction for proton-pump inhibitors was 13% (95% CI 8.3-18) and owning a pet dog aged < 6 months was 9.6% (95% CI 6.5-13). The population attributable fractions for these variables were similar when analysed by campylobacter species. Eating delicatessen meats was attributed to 31% (95% CI 0.0-54) of cases for C. coli and eating chicken pâté was attributed to 6.0% (95% CI 0.0-11).

CONCLUSIONS

The main risk factor for campylobacteriosis in Australia is consumption of chicken meat. However, contact with young pet dogs may also be an important source of infection. Proton-pump inhibitors are likely to increase vulnerability to infection.

Mining therapeutic targets from the antibiotic-resistant Campylobacter coli and virtual screening of natural product inhibitors against its riboflavin synthase

Campylobacter coli resides in the intestine of several commonly consumed animals, as well as water and soil. It leads to campylobacteriosis when humans eat raw/undercooked meat or come into contact with infected animals. A common manifestation of the infection is fever, nausea, headache, and diarrhea. Increasing antibiotic resistance is being observed in this pathogen. The increased incidence of C. coli infection, and post-infection complications like Guillain-Barré syndrome, make it an important pathogen. It is essential to find novel therapeutic targets and drugs against it, especially with the emergence of antibiotic-resistant strains. In the current study, genomes of 89 antibiotic-resistant strains of C. coli were downloaded from the PATRIC database. Potent drug targets (n = 36) were prioritized from the core genome (n = 1,337 genes) of this species. Riboflavin synthase was selected as a drug target and pharmacophore-based virtual screening was performed to predict its inhibitors from the NPASS (n =  ~ 30,000 compounds) natural product library. The top three docked compounds (NPC115144, NPC307895, and NPC470462) were selected for dynamics simulation (for 50 ns) and ADMET profiling. These identified compounds appear safe for targeting this pathogen and can be further validated by experimental analysis before clinical trials.

Cloning vectors for gene delivery, integration and expression in Campylobacter jejuni

Campylobacter genetics research is negatively impacted by a shortage of molecular tools for expressing DNA elements. A previous technique coupled an antibiotic resistance gene and its promoter to a gene of interest, inserting this expression unit into a conserved chromosomal location. Here the authors describe two new plasmids for construction and gene integration utilizing aspects of the previous type of expression unit. pBlueKan+cysM^Pro allows for the assembly of amplified DNA targets behind a kanamycin resistance marker and a constitutively transcribed cysM promoter. Transfer of the transcription unit to plasmid pCJR01 adds flanking regions of Campylobacter rRNA homology for recombination into conserved rRNA regions. System utility was demonstrated by restoring function of a flaAB deletion (RM3194ΔflaAB::tet) with a flaA gene or flaA/flaB combination.

Prevalence and characteristics of Campylobacter from the genital tract of primates and ruminants in Eastern China

Campylobacter infection is an important cause of genital failure in ruminants in developed countries. Although historically Campylobacter fetus subspecies fetus has been the main cause of abortion in sheep, C. jejuni is also increasingly associated with sheep abortions. However, limited information is known on Campylobacter-associated abortions in China. This study initially investigated the distribution of Campylobacter from the genital tracts of humans, monkeys, sheep, and cows in China from 2017 to 2018. Ten out of 2,126 (0.47%) samples from the genital tracts were Campylobacter positive, of which seven (70%) isolates were identified as C. jejuni. Phylogenetic analysis showed the high genetic diversity of these isolates. The human isolates were closely related to the sheep isolates implying inter-transmission of Campylobacter between humans and sheep according to the phylogenetic analysis. The acid resistance, adhesion, and invasion abilities of genital tract isolates were stronger than isolates from gastrointestinal tract, but no significant difference was observed in the virulence genes. We further found that three genital tract isolates belonged to the same cluster as gastrointestinal isolates from the same host. These findings suggested that there may be inter-transmission of Campylobacter between the genital and gastrointestinal tract. This article is protected by copyright. All rights reserved.

Genomic diversity and antimicrobial resistance of Campylobacter spp. from humans and livestock in Nigeria

Background

Campylobacter spp. are zoonotic pathogens, ubiquitous and are found naturally as commensals in livestock from where they can be transmitted to humans directly or through animal products. The genomic diversity and antimicrobial resistance profile of Campylobacter was investigated with a focus on C. jejuni and C. coli in humans and livestock (poultry and cattle) from Nigeria.

Methods

586 human stool samples and 472 faecal samples from livestock were cultured for thermophilic Campylobacter species on modified charcoal cefoperazone deoxycholate agar (mCCDA). Culture in combination with whole genome sequencing identified and confirmed the presence of Campylobacter in humans and animals from the study area. Further analysis of the sequences was performed to determine multilocus sequence types and genetic determinants of antimicrobial resistance to fluoroquinolone, betalactam, tetracycline and macrolide classes of antimicrobials.

Results

From the human stool samples tested, 50 (9%) were positive of which 33 (66%) were C. jejuni, 14 (28%) were C. coli while 3 (6%) were C. hyointestinalis. In livestock, 132 (28%) were positive. Thirty one (7%) were C. jejuni while 101 (21%) were C. coli. Whole genome sequencing and MLST of the isolates revealed a total of 32 sequence types (STs) identified from 47 human isolates while 48 STs were identified in 124 isolates from livestock indicating a population which was overall, genetically diverse with a few more dominant strains. The antimicrobial resistance profiles of the isolates indicated a higher prevalence of resistance in Campylobacter isolated from livestock than in humans. Generally, resistance was greatest for betalactams (42%) closely followed by fluoroquinolones (41%), tetracyclines (15%) and lastly macrolides (2%). Multidrug resistance to three or more antimicrobials was observed in 24 (13%) isolates from humans (n = 1, 4%) and chicken (n = 23, 96%).

Conclusions

This study has further contributed information about the epidemiology, genetic diversity and antimicrobial resistance profile of thermophilic Campylobacter in Nigeria.

Predicting Hospital Readmission for Campylobacteriosis from Electronic Health Records: A Machine Learning and Text Mining Perspective

(1) Background: This study investigates influential risk factors for predicting 30-day readmission to hospital for Campylobacter infections (CI). (2) Methods: We linked general practitioner and hospital admission records of 13,006 patients with CI in Wales (1990–2015). An approach called TF-zR (term frequency-zRelevance) technique was presented to evaluates how relevant a clinical term is to a patient in a cohort characterized by coded health records. The zR is a supervised term-weighting metric to assign weight to a term based on relative frequencies of the term across different classes. Cost-sensitive classifier with swarm optimization and weighted subset learning was integrated to identify influential clinical signals as predictors and optimal model for readmission prediction. (3) Results: From a pool of up to 17,506 variables, 33 most predictive factors were identified, including age, gender, Townsend deprivation quintiles, comorbidities, medications, and procedures. The predictive model predicted readmission with 73% sensitivity and 54% specificity. Variables associated with readmission included male gender, recurrent tonsillitis, non-healing open wounds, operation for in-gown toenails. Cystitis, paracetamol/codeine use, age (21–25), and heliclear triple pack use, were associated with a lower risk of readmission. (4) Conclusions: This study gives a profile of clustered variables that are predictive of readmission associated with campylobacteriosis.

Isolation Rate of Campylobacter Spp. and Detection of Virulence Genes of Campylobacter jejuni Across the Broiler Chain

The aim of the study was to identify the isolation rate of thermotolerant campylobacters in a small-scale broiler-meat production farm over a one-year period. The second deliverable of the study was to determine the potential virulence markers. The laboratory investigation was performed on 283 samples (cloacal swabs, caeca, carcass swabs) collected on three sampling points (farm, slaughter line, and cold storage). The isolates obtained with the conventional microbiological method were confirmed with multiplex PCR for identification of campylobacters. The presence of 10 virulence genes was analyzed in the C. jejuni isolates (flaA, racR, virB11, dnaJ, wlaN, cadF, ciaB, cdtA, cdtB, cdtC). Out of 283 samples, 169 (59.7%) were confirmed as Campylobacter spp., 111 (39.2%) C. jejuni, and 43 (15.2%) C. coli. C. jejuni was the most prevalent in all sampling points. Campylobacter spp. showed a characteristically seasonal prevalence with the highest isolation rate during the warmer period of the year. We detected the cadF and ciaB genes in all C. jejuni isolates. The flaA gene was present in 50% of the examined strains. The cdt genes (cdtA, cdtB, and cdtC) were confirmed in 52.8%, 52.8%, and 47.2% of the C. jejuni strains, respectively. C. jejuni showed 15 profiles of virulence patterns with four predominant profiles.

Campylobacter Contamination at Retail of Halal Chicken Produced in the United Kingdom

ABSTRACT

Campylobacter is the leading cause of human bacterial diarrheal disease worldwide, and poultry meat products account for the majority of human cases. Based on recent surveys, the Food Standards Agency has estimated the Campylobacter prevalence in fresh retail chicken in the United Kingdom to be 41.2%. However, such surveys have not distinguished between broiler chickens produced for different consumer demographic groups, such as the Halal market. Campylobacter colonization of broilers is difficult to prevent, especially during routine partial depopulation of flocks. Broilers produced for the Halal market may undergo multiple depopulation events, which may increase the risk of Campylobacter colonization and subsequent contamination of chicken meat. This study was conducted to determine the prevalence and levels of Campylobacter contamination in chicken meat produced for the Halal market in the United Kingdom. Campylobacter was identified and enumerated from the neck skin and outer packaging of 405 Halal chickens. Culture isolates were assigned to species via PCR assays, and disk diffusion assays were used to determine antimicrobial susceptibility. Logistic regression analysis was used to assess risk factors for Campylobacter contamination, the level of Campylobacter contamination among positive carcasses, and antimicrobial resistance. Campylobacter spp. were confirmed in 65.4% of neck skin samples and 17.1% of packaging samples. Neck skin samples had the highest level of contamination; 13.8% of samples had >1,000 CFU/g. Large birds had a significantly higher number of samples with >1,000 CFU/g (P < 0.001). and as chicken carcass weight increased, birds were more likely to be Campylobacter positive (P < 0.05). A high prevalence of resistance was seen to ciprofloxacin (42.0% of samples), and 38.5% of samples contained at least one multidrug-resistant Campylobacter isolate. This study revealed that Halal chicken has a higher Campylobacter prevalence than does non-Halal chicken. Interventions should be introduced to reduce this public health risk.

HIGHLIGHTS

Bovine and Pig Carcasses as a Source of Campylobacter in Poland: A Reservoir for Antimicrobial-Resistant Campylobacter coli

Campylobacter is one of the most common causes of foodborne bacterial infections worldwide. Why poultry has been shown to be one of the most significant sources of these bacteria, ruminants, especially cattle, are also responsible for a high number of human Campylobacter jejuni, and to a lesser extent Campylobacter coli, infections. In this study, bovine and pig carcasses in Poland were investigated for the presence of Campylobacter and for their antimicrobial resistance. A total of 204 swabs from bovine carcasses and 355 swab samples from pig carcasses were tested during 2014-2018. Campylobacter was identified in 129 (36.3%) of the pig and in 11 (5.4%) of the bovine carcasses, respectively. The pig isolates were classified as C. coli (121; 34.1%) or C. jejuni (8; 2.3%), whereas the bovine Campylobacter were identified either as C. jejuni (8; 3.9% isolates) or C. coli (3; 1.5% strains). Resistance of the isolates (n = 140) to erythromycin, ciprofloxacin, nalidixic acid, streptomycin, and tetracycline revealed that the vast majority of C. coli was resistant to streptomycin (106 isolates; 85.5%), tetracycline (97; 78.2%), nalidixic acid (90; 72.6%), and ciprofloxacin (88; 71.0%). Among C. jejuni isolates (n = 16) the resistance rates to all antibiotics were lower than in C. coli, irrespective of the origin. A total of 74 of 121 (61.2%) C. coli isolates from the pig carcasses and one of three such isolates from the bovine samples were multiresistant. Most of the C. coli (64 isolates; 85.3%) had the ciprofloxacin+nalidixic acid+streptomycin+tetracycline resistance profile. The results suggest that pig and bovine carcasses may be an underestimated reservoir of Campylobacter, especially for C. coli in pigs. The high antimicrobial resistance rates of such strains to streptomycin, quinolones, and tetracyclines highlight the need for monitoring of these bacteria in such food and food products.

Complete Genomic Sequences of Campylobacter coli Strains Isolated from Poultry Sold in Pennsylvania Farmers' Markets

Campylobacter strains were collected in a survey of fresh chicken carcasses in Pennsylvania farmers’ markets. Three Campylobacter coli strains were observed to have unique sequence variations in their gyrase subunit B genes, compared with other Campylobacter strains. The strains were sequenced and analyzed, producing genome sequences consisting of single closed chromosomes.

Campylobacter strains were collected in a survey of fresh chicken carcasses in Pennsylvania farmers’ markets. Three Campylobacter coli strains were observed to have unique sequence variations in their gyrase subunit B genes, compared with other Campylobacter strains. The strains were sequenced and analyzed, producing genome sequences consisting of single closed chromosomes.

Prevalence, Risk Factors, and Molecular Detection of Campylobacter in Farmed Cattle of Selected Districts in Bangladesh

A cross-sectional survey was conducted in selected districts of Bangladesh to estimate prevalence, risk factors, and molecular detection of Campylobacter isolates from 540 farmed cattle of 90 herds. As an individual sample, 540 feces, and as a pooled sample, 180 milk samples, 90 feed samples, 90 water samples, 90 manure samples, and 90 animal attendants' hand-rinse water were collected and tested via culture, biochemical, and molecular assays. A pretested semi-structured questionnaire was used to collect herd-level data on risk factors with the herd owners. The herd-level data on risk factors were analyzed through univariate and multivariate analyses, and a p-value <0.05 was considered statistically significant for all analyses. Overall, farm-level prevalence of bovine Campylobacter was enumerated to be 53.3% (95% confidence interval [CI]: 42.5-63.9%). The feces sample was found to be a high level of contamination of 30.9% (95% CI: 27-35%) followed by the manure swab (pooled) at 15.6% (95% CI: 8.8-24.7%). Campylobacter jejuni was documented as an abundant species (12.6%), followed by Campylobacter coli (5.1%), and Campylobacter fetus (0.3%). Older farms (>5 years of age), no/minimum cleaning and disinfection practices, along with animal roaming outside of the farm, were documented as significant risk factors for farm-level Campylobacter occurrence. Evidence-based control measures need to be taken through stringent biosecurity and hygienic measurement to lessen the load of the Campylobacter pathogen in the farm environment and prevent further transmission to animals and humans.

Method-Dependent Implications in Foodborne Pathogen Quantification: The Case of Campylobacter coli Survival on Meat as Comparatively Assessed by Colony Count and Viability PCR

The aim of the present study was to address method-dependent implications during the quantification of viable Campylobacter coli cells on meat over time. Traditional colony counting on selective and non-selective culture media along with an optimized viability real-time PCR utilizing propidium monoazide-quantitative PCR (PMA-qPCR), spheroplast formation and an internal sample process control (ISPC), were comparatively evaluated for monitoring the survival of C. coli on fresh lamb meat during refrigeration storage under normal atmospheric conditions. On day zero of three independent experiments, lamb meat pieces were artificially inoculated with C. coli and then stored under refrigeration for up to 8 days. Three meat samples were tested on different days and the mean counts were determined per quantification method. An overall reduction of the viable C. coli on lamb meat was observed regardless of the applied quantification scheme, but the rate of reduction followed a method-dependent pattern, the highest being observed for colony counting on modified charcoal cefoperazone deoxycholate agar (mCCDA). Univariate ANOVA indicated that the mean counts of viable C. coli using PMA-qPCR were significantly higher compared to Columbia blood agar (CBA) plating (0.32 log₁₀ cell equivalents, p = 0.015) and significantly lower when mCCDA was compared to CBA plating (0.88 log₁₀ CFU, p < 0.001), indicating that selective culture on mCCDA largely underestimated the number of culturable cells during the course of meat storage. PMA-qPCR outperformed the classical colony counting in terms of quantifying both the culturable and viable but non-culturable (VBNC) C. coli cells, which were generated over time on meat and are potentially infectious and equally important from a public health perspective as their culturable counterparts.

Population Biology and Comparative Genomics of Campylobacter Species

The zoonotic pathogen Campylobacter is the leading cause for bacterial foodborne infections in humans. Campylobacters are most commonly transmitted via the consumption of undercooked poultry meat or raw milk products. The decreasing costs of whole genome sequencing enabled large genome-based analyses of the evolution and population structure of this pathogen, as well as the development of novel high-throughput molecular typing methods. Here, we review the evolutionary development and the population diversity of the two most clinically relevant Campylobacter species; C. jejuni and C. coli. The state-of-the-art phylogenetic studies showed clustering of C. jejuni lineages into host specialists and generalists with coexisting lifestyles in chicken and livestock-associated hosts, as well as the separation of C. coli isolates of riparian origin (waterfowl, water) from C. coli isolated from clinical and farm-related samples. We will give an overview of recombination between both species and the potential impact of horizontal gene transfer on host adaptation in Campylobacter. Additionally, this review briefly places the current knowledge of the population structure of other Campylobacter species such as C. lari, C. concisus and C. upsaliensis into perspective. We also provide an overview of how molecular typing methods such as multilocus sequence typing (MLST) and whole genome MLST have been used to detect and trace Campylobacter outbreaks along the food chain.

Prevalence and antimicrobial susceptibility of Campylobacter isolated from retail chickens in Thailand

Campylobacter is an important foodborne pathogen causing bacterial gastroenteritis worldwide; however, there has been a lack of information over the past decade on its occurrence, antibiotic susceptibility and genetic diversity in Thailand. Poultry meat is considered as a reservoir for transmission of Campylobacter to humans. This study determines the prevalence and antimicrobial resistance patterns of Campylobacter spp. on chicken samples purchased from 50 local wet markets and supermarkets in central Thailand. Of the 296 samples, 99 (33.5%) were contaminated with C. jejuni, 54 (18.2%) were C. coli and 15 (5.1%) were contaminated with both species. Antibiotic resistance rate is higher among C. coli isolates; 100%, 76.8%, 37.7%, 36.2% and 13.0% were resistant to quinolones, cyclines, macrolides, clindamycin and gentamicin, respectively. Most of the C. jejuni isolates were resistant to quinolones (79.8%) and cyclines (38.6%) whereas resistance to macrolides, clindamycin and gentamicin was found to be 1.8%. Multi-drug resistance (i.e. to three or more unrelated antimicrobials) was detected in 37.7% of C. coli and 1.8% of C. jejuni isolates. This study has revealed high contamination rates and alarming levels of antimicrobial resistance in Campylobacter spp. isolated from retail chicken samples in Thailand, suggesting the necessity of implementing interventions to reduce its prevalence from farm to table in the country.

The effect of natural antimicrobials on the Campylobacter coli T6SS+/- during in vitro infection assays and on their ability to adhere to chicken skin and carcasses

Reducing the Campylobacter load on poultry carcasses represents a major tasks for the industry as its ability to reduce their presence is of major interest aiming to increase consumer safety. This study investigated the ability of a mixture of natural antimicrobials (A3001) to reduce the adherence of the T6SS^+/-C. coli isolates (NC1^hcp-, NC2 ^hcp- and NC3 ^hcp+) to chicken neck skin and whole carcasses. Overall, the antimicrobial mixture induced a significant reduction in the capability of our C. coli isolates to colonise the chicken skin (p < 0.05) and carcasses (p < 0.0001) but with a greater effect (≈3 log reduction) on the NC3 isolate. Using the HCT-8 in vitro infection model we also show that at a concentration of 0.5% A3001, the impact on the NC3 isolate is accompanied by the downregulation of the hcp gene (p = 0.0001), and indicator of the T6SS presence. The results described herein also indicated that these isolates are highly resistant to H₂O₂, up to 20 mM, suggesting a high resilience to environmental stresses. In summary our study shows that natural antimicrobials can reduce the ability of T6SS positive chicken C. coli isolates to adhere to chicken skin or to the whole carcass and to infect epithelial cells in vitro and could be considered a potential intervention at processor level.

Association between private drinking water wells and the incidence of Campylobacteriosis in Maryland: An ecological analysis using Foodborne Diseases Active Surveillance Network (FoodNet) data (2007-2016)

Campylobacter is a leading cause of bacterial foodborne illness in the United States. Campylobacter infections have most often been associated with food-related risk factors, such as the consumption of poultry and raw milk. Socioeconomic, agricultural and environmental factors, including drinking water source, can also influence the risk of campylobacteriosis. Approximately 19% of Maryland residents rely on private wells as their sole source of water. Given that the federal Safe Drinking Water Act does not regulate the water quality of private wells, these could be important non-foodborne transmission pathways for Campylobacter. To address this issue, data on the number of culture-confirmed cases of Campylobacter infection in Maryland between 2007 and 2016 were obtained from the Foodborne Diseases Active Surveillance Network. Cases were linked by zip code with data from the Maryland well permits registry, the 2010 U.S. Census, the 2016 American Community Survey, and the USDA Agricultural Census. Campylobacteriosis incidence rates and well prevalence were calculated by zip code. Negative binomial regression models were then constructed to evaluate the association between the prevalence of private wells, presence/absence of animal feeding operations and the incidence of campylobacteriosis across the physiographic provinces in Maryland. From 2007 to 2016, a total of 5746 cases of campylobacteriosis were reported in Maryland, and annual incidence rates ranged from 6.65 to 11.59 per 100,000 people. In our statewide analysis, a significant positive association was observed between well prevalence and increased campylobacteriosis incidence at the zip code level (Incidence Rate Ratio (IRR) = 1.35, 95% Confidence Interval (CI) = 1.11, 1.63). A significant positive association was also observed between well prevalence and increased campylobacteriosis incidence in the Appalachian and Coastal provinces of Maryland (IRR = 2.94, 95% CI = 1.11, 7.76 and IRR = 1.70, 95% CI = 1.25, 2.31, respectively). The presence of broiler chicken operations, increasing median age and percentage of residents living in poverty were also significantly associated with campylobacteriosis incidence at the zip code level in some physiographic provinces in Maryland. To our knowledge, these are the first US data to demonstrate an association between prevalence of private wells and campylobacteriosis incidence at the zip code level.

Factors affecting the species of Campylobacter colonizing chickens reared for meat

AIM

To investigate factors influencing Campylobacter spp. colonization of broiler chickens.

METHODS AND RESULTS

Campylobacters were isolated from caeca from 319 flocks of two different breeds (199 Cobb and 120 Hubbard), reared as standard (199), Freedom Food/corn fed (57), free-range (47) or organic (16). The standard category exclusively used Cobb birds slaughtered at 38-41 days. The Freedom Food/corn-fed and free-range Hubbard birds were slaughtered at 49-56 days and the organic flocks at 70 days. Campylobacters were picked at random from direct plates. Both breed of chicken (Hubbard) and age at slaughter were independently associated with increased likelihood of colonization by Campylobacter coli rather than Campylobacter jejuni, but breed could not be separated from other aspects of husbandry with the data available.

CONCLUSIONS

Chickens are frequently colonized by C. jejuni and C. coli and most human infections originate from poultry. In most developed countries approximately 90% of human infections are caused by C. jejuni, but fewer than 10% by C. coli. This might be due to C. coli being less pathogenic than C. jejuni to humans, and/or to chicken meat carrying fewer C. coli than C. jejuni. More investigations are needed into these aspects before it can be concluded that slaughtering older birds from slower-growing breeds would reduce the risk of human Campylobacter disease.

SIGNIFICANCE AND IMPACT OF THE STUDY

Meat from certain breeds of poultry are predominantly colonized by C. coli rather than C. jejuni. More research is needed to understand the impact this may have on the number and severity of human campylobacter infections.

DNA sequencing, genomes and genetic markers of microbes on fruits and vegetables

The development of DNA sequencing technology has provided an effective method for studying foodborne and phytopathogenic microorganisms on fruits and vegetables (F & V). DNA sequencing has successfully proceeded through three generations, including the tens of operating platforms. These advances have significantly promoted microbial whole‐genome sequencing (WGS) and DNA polymorphism research. Based on genomic and regional polymorphisms, genetic markers have been widely obtained. These molecular markers are used as targets for PCR or chip analyses to detect microbes at the genetic level. Furthermore, metagenomic analyses conducted by sequencing the hypervariable regions of ribosomal DNA (rDNA) have revealed comprehensive microbial communities in various studies on F & V. This review highlights the basic principles of three generations of DNA sequencing, and summarizes the WGS studies of and available DNA markers for major bacterial foodborne pathogens and phytopathogenic fungi found on F & V. In addition, rDNA sequencing‐based bacterial and fungal metagenomics are summarized under three topics. These findings deepen the understanding of DNA sequencing and its application in studies of foodborne and phytopathogenic microbes and shed light on strategies for the monitoring of F & V microbes and quality control.

Campylobacter colitis leads to toxic megacolon and multiple organ failure

A 58-year-old woman presented to the emergency department in a district general hospital with severe abdominal pain and diarrhoea, after collapsing at home. She was admitted to the intensive care unit (ICU) in septic shock, and with acute kidney injury. An initial CT scan was suggestive of colitis. She was treated for suspected gastroenteritis and her microbiology results showed Campylobacter coli as the causative organism. She failed to respond to antibiotics, and underwent serial contrast CTs which showed no progression of colitis. Colonoscopy performed on day 10 of her admission, however, revealed fulminant colitis. After a multidisciplinary meeting among gastroenterologists, general surgeons and intensivists, the patient underwent total colectomy with ileostomy. She made a slow but steady recovery in ICU, and subsequently in the ward, and was discharged to a local community hospital for further rehabilitation.

Prevalence, Population Diversity and Antimicrobial Resistance of Campylobacter coli Isolated in Italian Swine at Slaughterhouse

Campylobacter spp. are among the microorganisms most commonly associated with foodborne disease. Swine are known to be the main reservoir of Campylobacter coli and a possible source infection of humans as a result of carcass contamination at slaughter. The aim of this study was to evaluate the prevalence of C. coli contamination in swine carcasses, the antimicrobial resistance (AMR) patterns of isolates and the genetic diversity between strains obtained from swine and those isolated from humans. The prevalence of contamination was higher on carcasses (50.4%) than in faeces (32.9%). The 162 C. coli isolated from swine were examined by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). The results of PFGE indicated a high genetic diversity among the isolates, with 25 different PFGE types. MLST assigned 51 sequence types (STs) to isolates. The most common genotype was ST-854 (16.04%), ST-9264 (10.49 %) and ST-1016 (6.08 %). Results of AMR showed a high resistance to quinolones and fluoroquinolones together with aminoglycosides and tetracycline. Many strains were multi-resistant with predominant R-type TeSCipNa (57%). Five resistance genes were detected along with mutation in the gyrA gene. A strong correlation between phenotypic and genotypic resistance was found for fluoroquinolone and tetracycline. Genetic profiles obtained in swine isolates were compared to those of 11 human strains. All human strains and 64.19% of animal strains (104/162) were assigned to the ST-828 clonal complex.

Antimicrobial resistance patterns and molecular resistance markers of Campylobacter jejuni isolates from human diarrheal cases

The aim of this study is to characterize the antimicrobial resistance of Campylobacter jejuni recovered from diarrheal patients in Belgium, focusing on the genetic diversity of resistant strains and underlying molecular mechanisms of resistance among Campylobacter jejuni resistant strains isolated from diarrheal patients in Belgium. Susceptibility profile of 199 clinical C. jejuni isolates was determined by minimum inhibitory concentrations against six commonly-used antibiotics (ciprofloxacin, nalidixic acid, tetracycline, streptomycin, gentamicin, and erythromycin). High rates of resistance were observed against nalidixic acid (56.3%), ciprofloxacin (55.8%) and tetracycline (49.7%); these rates were similar to those obtained from different national reports in broilers intended for human consumption. Alternatively, lower resistance rates to streptomycin (4.5%) and erythromycin (2%), and absolute sensitivity to gentamicin were observed. C. jejuni isolates resistant to tetracycline or quinolones (ciprofloxacin and/or nalidixic acid) were screened for the presence of the tetO gene and the C257T mutation in the quinolone resistance determining region (QRDR) of the gyrase gene gyrA, respectively. Interestingly, some of the isolates that displayed phenotypic resistance to these antimicrobials lacked the corresponding genetic determinants. Among erythromycin-resistant isolates, a diverse array of potential molecular resistance mechanisms was investigated, including the presence of ermB and mutations in the 23S rRNA gene, the rplD and rplV ribosomal genes, and the regulatory region of the cmeABC operon. Two of the four erythromycin-resistant isolates harboured the A2075G transition mutation in the 23S rRNA gene; one of these isolates exhibited further mutations in rplD, rplV and in the cmeABC regulatory region. This study expands the current understanding of how different genetic determinants and particular clones shape the epidemiology of antimicrobial resistance in C. jejuni in Belgium. It also reveals many questions in need of further investigation, such as the role of other undetermined molecular mechanisms that may potentially contribute to the antimicrobial resistance of Campylobacter.

Viability Quantitative PCR Utilizing Propidium Monoazide, Spheroplast Formation, and Campylobacter coli as a Bacterial Model

A viability quantitative PCR (qPCR) utilizing propidium monoazide (PMA) is presented for rapid quantification of viable cells using the foodborne pathogen Campylobacter coli as a bacterial model. It includes optimized spheroplast formation via lysozyme and EDTA, induction of a mild osmotic shock for enhancing the selective penetration of PMA into dead cells, and exploitation of an internal sample process control (ISPC) involving cell inactivation to assess residual false-positive signals within each sample. Spheroplasting of bacteria in exponential phase did not permit PMA entrance into viable cells since a strong linear relationship was detected between simple qPCR and PMA-qPCR quantification, and no differences were observed regardless of whether spheroplasting was utilized. The PMA-qPCR signal suppression of dead cells was elevated using spheroplast formation. With regard to the ISPC, cell inactivation by hydrogen peroxide resulted in higher signal suppression during qPCR than heat inactivation did. Viability quantification of C. coli cells by optimized spheroplasting-PMA-qPCR with ISPC was successfully applied in an aging pure culture under aerobic conditions and artificially inoculated meat. The same method exhibited a high linear range of quantification (1.5 to 8.5 log10 viable cells ml-1), and results were highly correlated with culture-based enumeration. PMA-qPCR quantification of viable cells can be affected by their rigidity, age, culture media, and niches, but spheroplast formation along with osmotic shock and the use of a proper ISPC can address such variations. The developed methodology could detect cells in a viable-but-nonculturable state and might be utilized for the quantification of other Gram-negative bacteria.IMPORTANCE There is need for rapid and accurate methods to detect viable bacterial cells of foodborne pathogens. Conventional culture-based methods are time-consuming and unable to detect bacteria in a viable-but-nonculturable state. The high sensitivity and specificity of the quantitative PCR (qPCR) are negated by its inability to differentiate the DNAs from viable and dead cells. The combination of propidium monoazide (PMA), a DNA-intercalating dye, with qPCR assays is promising for detection of viable cells. Despite encouraging results, these assays still encounter various challenges, such as false-positive signals by dead cells and the lack of an internal control identifying these signals per sample. The significance of our research lies in enhancing the selective entrance of PMA into dead Campylobacter coli cells via spheroplasting and in developing an internal sample process control, thus delivering reliable results in pure cultures and meat samples, approaches that can be applicable to other Gram-negative pathogens.

Methods for generating hypotheses in human enteric illness outbreak investigations: a scoping review of the evidence

Enteric illness outbreaks are complex events, therefore, outbreak investigators use many different hypothesis generation methods depending on the situation. This scoping review was conducted to describe methods used to generate a hypothesis during enteric illness outbreak investigations. The search included five databases and grey literature for articles published between 1 January 2000 and 2 May 2015. Relevance screening and article characterisation were conducted by two independent reviewers using pretested forms. There were 903 outbreaks that described hypothesis generation methods and 33 papers which focused on the evaluation of hypothesis generation methods. Common hypothesis generation methods described are analytic studies (64.8%), descriptive epidemiology (33.7%), food or environmental sampling (32.8%) and facility inspections (27.9%). The least common methods included the use of a single interviewer (0.4%) and investigation of outliers (0.4%). Most studies reported using two or more methods to generate hypotheses (81.2%), with 29.2% of studies reporting using four or more. The use of multiple different hypothesis generation methods both within and between outbreaks highlights the complexity of enteric illness outbreak investigations. Future research should examine the effectiveness of each method and the contexts for which each is most effective in efficiently leading to source identification.

Differences in virulence gene expression between human blood and stool Campylobacter coli clade 1 ST828CC isolates

BACKGROUND

Campylobacter colonise the gastrointestinal tract of warm-blooded animals and are major enteropathogens in humans. C. coli is less common than C. jejuni and accounts for about 10% of the total number of Campylobacter infections although the two species seem to share many virulence determinants. Campylobacter bacteraemia is rare, estimated to occur in less than 1% of the infections, and the exact mechanisms regulating the progression of the infection from the gastrointestinal tract to the blood stream are unclear. Here, we looked at the contribution of C. coli to Campylobacter infections and further compared various virulence traits in C. coli clade 1 blood and stool isolates.

RESULTS

We assessed the numbers of C. jejuni and C. coli among typed isolates in the PubMLST database and found that C. coli accounted for 25.9% of blood isolates, but only 8.9% of the stool isolates. Phylogenetic analysis of 128 C. coli clade 1 whole genome sequences deposited to NCBI revealed no specific clustering of the human blood, stool or animal isolates. Of the six C. coli isolates chosen for phenotypic analyses, stool isolates adhered significantly better to human HT-29 colon cancer cells than the blood isolates, while there was no difference in induced IL-8 levels between the isolates. Furthermore, the stool isolates had two- to fourfold higher RNA expression levels of the flpA, ciaB, iamA and cdt virulence genes than the blood isolates. Finally, we looked at the gene structure of the cdtA, B and C toxin genes and found numerous nucleotide additions and deletions disrupting the open reading frames. In contrast to 58% isolates of animal origin, only 38% and 32% of human blood and stool isolates, respectively, had all three cdt genes intact, a prerequisite to produce functional toxins.

CONCLUSIONS

This study reveals interesting differences between C. coli clade 1 isolates of human and animal origin on one hand, and also between human blood and stool isolates, on the other. The results suggest that C. coli might downregulate and/or inactivate various virulence determinants as the isolates pass from the animal host to the human gastrointestinal tract and enter the human blood stream.

Disinfectant and Antimicrobial Susceptibility Profiles of Campylobacter coli Isolated in 1998 to 1999 and 2015 from Swine and Commercial Pork Chops

Susceptibility profiles were determined for 111 Campylobacter coli strains obtained in 1998 to 1999 and 2015 from market age pigs and pork chops against 22 disinfectants and 9 antimicrobials. Resistance to tetracycline (TET) was observed in 44.4% of 1998 to 1999 strains, and the antibiotic resistance profile was TET. But strains obtained in 2015 from swine and retail pork chops had 75% TET resistance and the antibiotic resistance profile was TET, followed by azithromycin-erythromycin-TET-telithromycin-clindamycin. Antimicrobial resistance increased in 2015 strains. All strains were resistant to triclosan, and 84.1% and 95.8% of strains in 1998 to 1999 and 2015, respectively, were chlorhexidine resistant. All strains were susceptible to benzalkonium chloride. There was a shift toward higher susceptibility to chlorhexidine, triclosan, P-128, OdoBan, CPB, and CPC in 2015 swine and pork chop strains compared with 1998 to 1999 strains. The disinfectants Tek-Trol and providone-iodine, tris(hydroxylmethyl)nitromethane (THN) and formaldehyde demonstrated the highest susceptibilities. Didecyldimethylammonium chloride (C10AC) appeared to be about equally effective as benzyldimethyltetradecylammonium chloride (C14BAC) for inhibiting C. coli, and both were more effective than C8AC and C12BAC, but C16BAC was not efficient at inhibiting C. coli. The BACs, C12BAC and C14BAC, were the most effective ingredients in DC&R. Also, C12BAC and C14BAC, or these two in synergy with C10AC were responsible for inhibition of C. coli at high P-128 MICs. No cross-resistance was observed between antibiotics and disinfectants. The continued use of THN and formaldehyde in DC&R should be evaluated since these components are not effective, and their inclusion adds unwanted chemicals in the environment. PRACTICAL APPLICATION: Campylobacter species cause diarrheal disease throughout the world. Disinfectants are often used on the farm, in veterinary medicine, by the food processing industry, in restaurants, and in consumer's homes. Limited information is available in the literature showing how disinfectants or disinfectant components may affect the many different foodborne pathogens, and, specifically, Campylobacter coli studied here. The knowledge generated in this study concerning the interactions of a broad array of disinfectants against C. coli may well affect the types of disinfectants and disinfectant formulations allowable for use by medical personnel, producers, food processors, restaurants, and consumers.

Differentiation of Campylobacter fetus Subspecies by Proteotyping

Campylobacter fetus is a causative agent of intestinal illness and, occasionally, severe systemic infections and meningitis. C. fetus currently comprises three subspecies: C. fetus subspecies fetus (Cff), C. fetus subspecies venerealis (Cfv), and C. fetus subspecies testudinum (Cft). Cff and Cfv are primarily associated with mammals whereas Cft is associated with reptiles. To offer an alternative to laborious sequence-based techniques such as multilocus sequence typing (MLST) and polymerase chain reaction (PCR)-ribotyping for this species, the purpose of the study was to develop a typing scheme based on proteotyping. In total, 41 representative C. fetus strains were analyzed by intact cell mass spectrometry and compared to MLST results. Biomarkers detected in the mass spectrum of C. fetus subsp. fetus reference strain LMG 6442 (NCTC 10842) as well as corresponding isoforms were associated with the respective amino acid sequences and added to the C. fetus proteotyping scheme. In combination, the 9 identified biomarkers allow the differentiation of Cft subspecies strains from Cff and Cfv subspecies strains. Biomarkers to distinguish between Cff and Cfv were not found. The results of the study show the potential of proteotyping to differentiate different subspecies, but also the limitations of the method.

Phylogenetic Diversity and Antimicrobial Resistance of Campylobacter coli from Humans and Animals in Japan

The phylogenetic diversity and antimicrobial resistance (AMR) of Campylobacter coli from humans and animals in Japan between 2008 and 2014 were investigated. A total of 338 foodborne campylobacterioses were reported in Osaka, and C. coli was isolated from 38 cases (11.2%). In the present study, 119 C. coli strains (42 from humans, 25 each from poultry, cattle, and swine, and 2 from wild mallard) were examined by multilocus sequence typing (MLST). MLST assigned 36 sequence types (STs), including 14 novel STs; all human strains and 91% of animal strains (70/77) were assigned to the ST-828 clonal complex. The predominant human ST was ST-860 (18/42, 43%), followed by ST-1068 (8/42, 19%); these STs were also predominant in poultry (ST-860, 9/25, 36%) and cattle (ST-1068, 18/25, 72%). ST-1562 was only predominant in swine (11/25, 44.0%). Swine strains showed the greatest resistance to erythromycin (EM; 92.0%), while EM resistance was only found in 2 out of the 42 human strains examined (4.8%). All EM-resistant swine strains (n=15) exhibited a common point mutation in the 23S rRNA sequence (A2085G), and the tetO gene was detected in 22 out of the 23 TET-resistant swine strains. A whole genome sequencing analysis of four representative swine ST-1562 strains revealed abundant AMR-associated gene clusters in their genomes, suggesting horizontal gene transfer events during host adaptation. This is the first study to demonstrate the phylogenetic diversity and AMR profiles of C. coli in Japan. The present results suggest that poultry and cattle are major reservoirs, improving our knowledge on the epidemiological and ecological traits of this pathogen.

Campylobacter coli Clade 3 Isolates Induce Rapid Cell Death In Vitro

Campylobacter bacteria are major human enteropathogens. Campylobacter coli shows less genetic diversity than C. jejuni and clusters into three clades, of which clade 1 includes most human and farm animal isolates, while environmental C. coli isolates mainly belong to clades 2 and 3. Recently, we sequenced the whole genomes of eight C. coli clade 2 and 3 isolates cultivated from water, and here we studied their interaction with human HT-29 colon cancer cells compared to that of clinical clade 1 isolates. All C. coli clade 3 isolates already caused cell necrosis 1 to 2 h after inoculation, whereas none of the clade 1 and 2 isolates analyzed induced cell death. Isolates from clades 2 and 3 adhered to epithelial cells better than clade 1 isolates, but all isolates induced similar levels of interleukin-8 (IL-8). Alignment and phylogenetic analysis of the translated putative virulence genes cadF, flpA, iamA, ciaB, and ceuE revealed clade-specific protein sequence variations, with clade 1 and 2 sequences being more closely related and clade 3 sequences being further apart, in general. Moreover, when RNA levels were measured, clade 3 isolates showed significantly lower levels of expression of cadF, iamA, and ceuE than clade 2 isolates, while flpA expression levels were higher in clade 3 isolates. The cytolethal distending toxin genes were also expressed in clades 2 and 3, although there was no difference between clades. Our findings demonstrate differences between the effects of C. coli clade 1, 2, and 3 isolates on human cells and suggest that C. coli clade 3 might be more virulent than clade 2 due to the observed cytotoxicity.IMPORTANCECampylobacter coli is a common zoonotic cause of gastroenteritis in humans worldwide. The majority of infections are caused by C. coli clade 1 isolates, whereas infections due to clade 2 and 3 isolates are rare. Whether this depends on a low prevalence of clade 2 and 3 isolates in reservoirs important for human infections or their lower ability to cause human disease is unknown. Here, we studied the effects of C. coli clade 2 and 3 isolates on a human cell line. These isolates adhered to human cells to a higher degree than clinical clade 1 isolates. Furthermore, we could show that C. coli clade 3 isolates rapidly induced cell death, suggesting differences in the virulence of C. coli The exact mechanism of cell death remains to be revealed, but selected genes showed interesting clade-specific expression patterns.

Case-case analyses of cryptosporidiosis and giardiasis using routine national surveillance data in the United States - 2005-2015

Understanding endemic infectious disease risk factors through traditional epidemiological tools is challenging. Population-based case-control studies are costly and time-consuming. A case-case analyses using surveillance data addresses these limitations by using resources more efficiently. We conducted a case-case analyses using routine surveillance data reported by 16 U.S. states (2005-2015), wherein reported cases of salmonellosis were used as a comparison group to identify exposure associations with reported cases of cryptosporidiosis and giardiasis. Odds ratios adjusted for age and reporting state (aOR) and 95% confidence intervals (95% CI) were calculated. A total of 10 704 cryptosporidiosis cases, 17 544 giardiasis cases, and 106 351 salmonellosis cases were included in this analyses. When compared with cases of salmonellosis, exposure to treated recreational water (aOR 4.7, 95% CI 4.3-5.0) and livestock (aOR: 3.2; 95% CI: 2.9-3.5) were significantly associated with cryptosporidiosis and exposure to untreated drinking (aOR 4.1, 95% CI 3.6-4.7) and recreational water (aOR 4.1, 95% CI 3.7-4.5) were associated with giardiasis. Our analyses shows that routine surveillance data with standardised exposure information can be used to identify associations of interest for cryptosporidiosis and giardiasis.

Dairy Cattle, a Potential Reservoir of Human Campylobacteriosis: Epidemiological and Molecular Characterization of Campylobacter jejuni From Cattle Farms

Campylobacter jejuni is a major foodborne pathogen that is increasingly found worldwide and that is transmitted to humans through meat or dairy products. A detailed understanding of the prevalence and characteristics of C. jejuni in dairy cattle farms, which are likely to become sources of contamination, is imperative and is currently lacking. In this study, a total of 295 dairy cattle farm samples from 15 farms (24 visits) in Korea were collected. C. jejuni prevalence at the farm level was 60% (9/15) and at the animal level was 23.8% (68/266). Using the multivariable generalized estimating equation (GEE) model based on farm-environmental factors, we estimated that a high density of cattle and average environmental temperature (7 days prior to sampling) below 24°C affects the presence and survival of C. jejuni in the farm environment. Cattle isolates, together with C. jejuni from other sources (chicken and human), were genetically characterized based on analysis of 10 virulence and survival genes. A total of 19 virulence profile types were identified, with type 01 carrying eight genes (all except hcp and virB11) being the most prevalent. The prevalence of virB11 and hcp was significantly higher in isolates from cattle than in those from other sources (p < 0.05). Multilocus sequence typing (MLST) of C. jejuni isolates from three different sources mainly clustered in the CC-21 and CC-48. Within the CC-21 and CC-48 clusters, cattle isolates shared an indistinguishable pattern with human isolates according to pulsed-field gel electrophoresis (PFGE) and flaA-restriction fragment length polymorphism (RFLP) typing. This suggests that CC-21 and CC-48 C. jejuni from dairy cattle are genetically related to clinical campylobacteriosis isolates. In conclusion, the farm environment influences the presence and survival of C. jejuni, which may play an important role in cycles of cattle re-infection, and dairy cattle represent potential reservoirs of human campylobacteriosis. Thus, environmental management practices could be implemented on cattle farms to reduce the shedding of C. jejuni from cattle, subsequently reducing the potential risk of the spread of cattle-derived C. jejuni to humans through the food chain.

Real-time recombinase polymerase amplification assay for the rapid and sensitive detection of Campylobacter jejuni in food samples

Campylobacter jejuni (C. jejuni), a foodborne pathogen, is a major contributor to human bacterial gastroenteritis worldwide and detrimental to public health. It is crucial for initiating appropriate outbreak control strategies to rapidly detect C. jejuni. As a novel isothermal gene amplification technique, recombinase polymerase amplification (RPA) has been developed for the molecular detection of diverse pathogens. In this study, we developed a real-time RPA assay so as to achieve the rapid and efficient detection of C. jejuni by targeting the hipO gene. The specificity and senstivity of real-time RPA was validated and the practical applicability of the method for the detection of C. jejuni in artificially contaminated milk and chicken breast samples was proved by comparing their reaction time, sensitivity, and efficacy with those of real-time PCR and culture-based methods. Based on the real-time RPA assay, analysis time was reduced to approximately 13 mins from 60 mins and the results were as reliable as those of the real-time PCR assay. Taken together, in terms of the detection of C. jejuni, the real-time RPA method was simple, rapid, sensitive, and reliable.

Campylobacter coli From Retail Liver and Meat Products Is More Aerotolerant Than Campylobacter jejuni

Aerotolerance in the microaerophilic species Campylobacter was previously reported and could increase bacterial survival and transmission in foods during stressful processing and storage conditions. In this study, 167 Campylobacter isolates (76 C. jejuni and 91 C. coli) were screened for aerotolerance; these strains were previously isolated from retail chicken meat, chicken livers, chicken gizzards, turkey, pork, and beef liver samples. Bacterial cultures were incubated aerobically in Mueller Hinton broth with agitation and viable cell counts were taken at 0, 6, 12, and 24 h. Approximately 47% of the screened Campylobacter isolates were aerotolerant (viable after a 12-h aerobic incubation period), whereas 24% were hyper-aerotolerant (viable after a 24-h aerobic incubation). A greater prevalence of aerotolerant strains (80%) was found among C. coli isolates as compared to C. jejuni isolates (6%). Differences in the oxidative stress response related genes were detected among C. jejuni and C. coli isolates when comparative genomics was used to analyze 17 Whole Genome Sequenced (WGS) strains from our laboratory. Genes encoding putative transcriptional regulator proteins and a catalase-like heme binding protein were found in C. coli genomes, but were absent in the genomes of C. jejuni. PCR screening showed the presence of a catalase-like protein gene in 75% (68/91) of C. coli strains, which was absent in all tested C. jejuni strains. While about 79% (30/38) of the hyper-aerotolerant C. coli strains harbored the catalase-like protein gene, the gene was also present in a number of the aerosensitive strains. The Catalase like protein gene was found to be expressed in both aerobic and microaerobic conditions with a 2-fold higher gene expression detected in aerobic conditions for an aerosensitive strain. However, the exact function of the gene remains unclear and awaits further investigation. In conclusion, aerotolerant Campylobacter strains (especially C. coli) are prevalent in various retail meats. Further studies are needed to investigate whether the genes encoding catalase-like heme binding protein and putative transcriptional regulators in C. coli strains are involved in stress response.

Phylogenetic Relatedness Among Plasmids Harbored by Campylobacter jejuni and Campylobacter coli Isolated From Retail Meats

Campylobacter jejuni and Campylobacter coli are two of the major causes of foodborne illness. In this study, 29 plasmids isolated from 20 retail meat isolates of Campylobacter jejuni and Campylobacter coli were fully-sequenced individually or as a part of a whole genome sequencing approach. The fully-sequenced plasmids ranged in size from 3 to 119 kb. Molecular characterization of the sequenced plasmids was based on pangenomic analysis and types of genes present on these plasmids and similar ones from GenBank. The plasmids were categorized into four different groups. These groups include type-1 that consisted mainly of pTet plasmids with the tetO gene, type-2 plasmids commonly found in C. coli strains, type-3 which has pVir plasmids, and type-4 that consisted mainly of smaller plasmids. The type-2 plasmids were unique, common among C. coli strains, and carried several conjugative transfer genes. The type-2 plasmids were most similar to a plasmid from Helicobacter pullorum. Maximum parsimony analysis and NeighborNet analysis were used to assess the phylogenetic relatedness among the 29 plasmid sequences presented in this study in addition to the other 104 plasmid sequences of Campylobacter species available in GenBank to date. Results from MP analysis revealed multiple lineages among Campylobacter plasmids which was supported by NeighborNet analysis. Clustering of plasmids did not conform to species-specific clades which suggested an intra-species dissemination of plasmids among Campylobacter species. To our knowledge, this is the first extensive phylogenetic analysis of Campylobacter plasmids sequenced to date.

Interactions of organic acids with Campylobacter coli from swine

Campylobacter coli is a bacterial species that is a major cause of diarrheal disease worldwide, and Campylobacter spp. are among the top 5 foodborne pathogens in the United States. During food production organic acids (OAs) are often used to remove bacteria from animal carcasses. The interactions of six OAs with 111 C. coli strains obtained from swine and retail pork chops were studied by determining the molar minimum inhibitory concentrations (MICMs) of the C. coli strains, and the pH at the MICMs. The Henderson-Hasselbalch equation was used to calculate the concentrations of the undissociated and dissociated OAs at the MICMs of the C. coli strains. The results for the 111 different C. coli strains obtained from different locations were treated as a single group for each OA since many of the C. coli strains behaved similarly to each different OA. Inhibition of C. coli was not dependent on pH or on the undissociated OA species, but C. coli inhibition correlated with the dissociated OA species. Therefore, if the concentration of the dissociated OAs decreases from optimum, one may then expect that C. coli bacteria would escape disinfection. The concentration of the dissociated OA should be carefully controlled in a carcass wash. We suggest maintaining a concentration of the dissociated acetic, butyric, citric, formic, lactic and propionic acids at 29, 23, 11, 35, 22 and 25 mM, respectively, when using a carcass wash with these OAs to remove C. coli bacteria. However, due to C. coli utilization of acetate, formate, lactate and propionate, these four OAs may not be the best choice to use for a carcass wash to remove C. coli contamination. Of the six OAs, citric acid was the most efficient at inhibiting C. coli.

Case-case analysis of Campylobacter and Salmonella - using surveillance data for outbreak investigations and monitoring routine risk factors

Utilising routine surveillance data, this study presents a method for generating a baseline comparison that can be used in future foodborne outbreak investigations following a case-case methodology. Salmonella and Campylobacter cases (2012-2015) from Maricopa County, AZ were compared to determine differences in risk factors, symptoms and demographics. For foods and other risk factors, adjusted odds ratios were developed using Campylobacter as the reference. Comparisons were also made for three major Salmonella subtypes, Typhimurium, Enteritidis and Poona as compared with Campylobacter. Salmonella cases were younger, while Campylobacter cases were more Hispanic and female. Campylobacter cases reported consuming peppers, sprouts, poultry, queso fresco, eggs and raw nuts more and reported contact with animal products, birds, visiting a farm or dairy, owning a pet, a sick pet, swimming in a river, lake or pond, or handling multiple raw meats more. Salmonella cases reported visiting a petting zoo and contact with a reptile more. There were significant variations by Salmonella subtype in both foods and exposures. We recommend departments conduct this analysis to generate a baseline comparison and a running average of relevant odds ratios allowing staff to focus on trace-back of contaminated food items earlier in the outbreak investigation process.

Campylobacter jejuni virulence genes and immune-inflammatory biomarkers association with growth impairment in children from Northeastern Brazil

Campylobacter spp. have been associated with anthropometric Z-score decrements, but the role of specific virulence genes associated with these outcomes has not been explored. This study aimed to investigate whether specific Campylobacter jejuni virulence-related gene and immune-inflammatory biomarkers are associated with malnutrition in children from Northeastern Brazil. A case-control study was performed in Fortaleza, Brazil. Children aging 6-24 months were characterized as malnourished (cases) if weight-for-age Z-score (WAZ) = 2 and as nourished (controls) if WAZ ≥ 1. DNA samples were extracted from stools and screened for C. jejuni/coli by real-time PCR. A subsequent C. jejuni-specific PCR was employed and positive samples were evaluated for 18 C. jejuni virulence genes by using four multiplex PCRs. C. jejuni was detected in 9.71% (33/340) of the children's samples, being 63.63% (21/33) from nourished and 37.37% (12/33) from malnourished children. The cadF, iamA, cheW, and sodB genes were the most frequent genes (100%, 90.9%, 87.9%, and 75.8%, respectively), while some others (ceuE, jlpA, pldA, and pVir) showed low rates (all below 6%). Malnourished children were significantly associated with infection with C. jejuni strains lacking cdtB gene (active subunit of cytolethal distending toxin) and harboring flgE gene (flagellar hook protein). These strains were also associated with children presenting increased serum SAA and sCD-14, but decreased IgG anti-LPS. These data reinforce the impact of Campylobacter jejuni infection on children without diarrhea and highlight the contribution of a specific virulence gene profile, cdtB(-)flgE(+) and increased systemic response in malnutrition children.

Exposure to whole chicken carcasses may present a greater risk of campylobacteriosis compared to exposure to chicken drumsticks

In New Zealand, the major risk factor for campylobacteriosis has been identified as poultry consumption. New Zealanders consume different types of chicken meat which undergo different processing before entering the retail chain. The manipulations and jointing of chicken carcasses into pieces and the subsequent processing and packaging have the potential to cross-contaminate and reshuffle bacterial pathogens among the different products sold. The aim of this study was to analyse: (a) the differences in the viable count and population genetic structure between Campylobacter isolated from chicken drumsticks and whole carcass meat for retail sale over a 1-year period; and (b) the genetic relatedness of human and chicken isolates collected concurrently. Enumeration of Campylobacter was performed using a spiral plater combined with manual spread plating. Campylobacter isolates were identified by polymerase chain reaction and typed by multilocus sequence typing (MLST). C. jejuni was the dominant species among both whole carcasses (63.5%) and drumsticks samples (73.8%), followed by C. coli (27% and 23.1%, respectively). After sample weight adjustment, whole carcasses showed significantly higher Campylobacter counts than drumsticks, with a significant difference in the counts between the commercial suppliers in both types of retail meat. MLST revealed 28 different sequence types among the two types of meat. Using permutational multivariate analysis of variance, statistically significant differences in the population genetic structures were observed between different suppliers but were not observed between the two types of chicken retail meat. In conclusion, we found differences in Campylobacter viable counts, suggesting consumption of whole carcasses may determine an exposure to a higher number of Campylobacter bacteria than consumption of chicken drumsticks. The Campylobacter population genetic structure did not differ between the two types of chicken retail meat. Therefore, source attribution studies based on MLST are unlikely to be biased by the selection of these types of retail meat during sampling.