Campylobacter upsaliensis: waiting in the wings

Genetic characteristics and potential pathogenic agents in Campylobacter upsaliensis based on genomic analysis

Campylobacter upsaliensis was the most common Campylobacter species in pets' gastrointestinal tracts and has been isolated from patients with bacteremia, hemolytic-uremic syndrome, spontaneous abortion, and Guillain-Barré syndrome. However, the genetic characteristics and the full extent of its significance as a human pathogen remain to be fully understood. This study involved an investigation for genomic analysis of 154 strains from different sources and additional antimicrobial resistance profiles of 26 strains for this species. The genomes contained 1,558-1,971 CDS and the genome sizes were estimated to vary from 1.53 Mb to 1.86 Mb, with an average GC content of  34.71%. The entire analyzed genomes could be divided into three clades (A, B, and C) based on ANI and phylogenomic analysis. Significantly, nearly all strains in Clade B were isolated from patient samples, and the virulence-related sequences FlgD, GmhA, and CdtC might serve as determining factors for the classification of Clade B. Half of the tested isolates had MIC values over 64 μg mL-1 for nalidixic acid, gentamicin, and streptomycin. Isolates from pets in China carried more resistant elements in the genomes. This study both provided a comprehensive profile of C. upsaliensis for its genomic features and suggested some pathogenic agents for human infection with this species.

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 Species, Microbiological Source Tracking and Risk Assessment of Bacterial pathogens

Campylobacter species continue to remain critical pathogens of public health interest. They are responsible for approximately 500 million cases of gastroenteritis per year worldwide. Infection occurs through the consumption of contaminated food and water. Microbial risk assessment and source tracking are crucial epidemiological strategies to monitor the outbreak of campylobacteriosis effectively. Various methods have been proposed for microbial source tracking and risk assessment, most of which rely on conventional microbiological techniques such as detecting fecal indicator organisms and other novel microbial source tracking methods, including library-dependent microbial source tracking and library-independent source tracking approaches. However, both the traditional and novel methods have their setbacks. For example, while the conventional techniques are associated with a poor correlation between indicator organism and pathogen presence, on the other hand, it is impractical to interpret qPCR-generated markers to establish the exact human health risks even though it can give information regarding the potential source and relative human risk. Therefore, this article provides up-to-date information on campylobacteriosis, various approaches for source attribution, and risk assessment of bacterial pathogens, including next-generation sequencing approaches such as shotgun metagenomics, which effectively answer the questions of potential pathogens are there and in what quantities.

Whole-Genome Shotgun Metagenomic Sequencing Reveals Distinct Gut Microbiome Signatures of Obese Cats

Overweight and obesity are growing health problems in domestic cats, increasing the risks of insulin resistance, lipid dyscrasias, neoplasia, cardiovascular disease, and decreasing longevity. The signature of obesity in the feline gut microbiota has not been studied at the whole-genome metagenomic level. We performed whole-genome shotgun metagenomic sequencing in the fecal samples of eight overweight/obese and eight normal cats housed in the same research environment. We obtained 271 Gbp of sequences and generated a 961-Mbp de novo reference contig assembly, with 1.14 million annotated microbial genes. In the obese cat microbiome, we discovered a significant reduction in microbial diversity (P < 0.01) and Firmicutes abundance (P = 0.005), as well as decreased Firmicutes/Bacteroidetes ratios (P = 0.02), which is the inverse of obese human/mouse microbiota. Linear discriminant analysis and quantitative PCR (qPCR) validation revealed significant increases of Bifidobacterium sp., Olsenella provencensis, Dialister sp.CAG:486, and Campylobacter upsaliensis as the hallmark of obese microbiota among 400 enriched species, whereas 1,525 bacterial species have decreased abundance in the obese microbiome. Phascolarctobacterium succinatutens and an uncharacterized Erysipelotrichaceae bacterium are highly abundant (>0.05%) in the normal gut with over 400-fold depletion in the obese microbiome. Fatty acid synthesis-related pathways are significantly overrepresented in the obese compared with the normal cat microbiome. In conclusion, we discovered dramatically decreased microbial diversity in obese cat gut microbiota, suggesting potential dysbiosis. A panel of seven significantly altered, highly abundant species can serve as a microbiome indicator of obesity. Our findings in the obese cat microbiome composition, abundance, and functional capacities provide new insights into feline obesity.

IMPORTANCE Obesity affects around 45% of domestic cats, and licensed drugs for treating feline obesity are lacking. Physical exercise and calorie restrictions are commonly used for weight loss but with limited efficacy. Through comprehensive analyses of normal and obese cat gut bacteria flora, we identified dramatic shifts in the obese gut microbiome, including four bacterial species significantly enriched and two species depleted in the obese cats. The key bacterial community and functional capacity alterations discovered from this study will inform new weight management strategies for obese cats, such as evaluations of specific diet formulas that alter the microbiome composition, and the development of prebiotics and probiotics that promote the increase of beneficial species and the depletion of obesity-associated species. Interestingly, these bacteria identified in our study were also reported to affect the weight loss success in human patients, suggesting translational potential in human obesity.

Comparing Azithromycin to Amoxicillin in the Management of Uncomplicated Severe Acute Malnutrition in Burkina Faso: A Pilot Randomized Trial

Azithromycin is a promising alternative to amoxicillin in the management of uncomplicated severe acute malnutrition (SAM) as it can be administered as a single dose and has efficacy against several pathogens causing infectious disease and mortality in children under 5. In this pilot trial, we aimed to establish the feasibility of a larger randomized controlled trial and provide preliminary evidence comparing the effect of azithromycin to amoxicillin on weight gain in children with uncomplicated SAM. We enrolled children 6-59 months old with uncomplicated SAM at six healthcare centers in Burkina Faso. Participants were randomized to a single dose of azithromycin or a 7-day course of amoxicillin and followed weekly until nutritional recovery and again at 8 weeks. Apart from antibiotics, participants received standard of care, which includes ready-to-use therapeutic food. Primary feasibility outcomes included enrollment potential, refusals, and loss to follow-up. The primary clinical outcome was weight gain (g/kg/day) over 8 weeks. Outcome assessors were masked. Between June and October 2020, 312 children were screened, 301 were enrolled with zero refusals, and 282 (93.6%) completed the 8-week visit. Average weight gain was 2.5 g/kg/day (standard deviation [SD] 2.0) in the azithromycin group and 2.6 (SD 1.7) in the amoxicillin group (mean difference -0.1, 95% CI -0.5 to 0.3, P = 0.63). Fewer adverse events were reported in the azithromycin group (risk ratio 0.50, 95% CI 0.31-0.82, P = 0.006). With strong enrollment and follow-up, a fully powered trial in this setting is feasible.

Survival capability of Campylobacter upsaliensis under environmental stresses

Objective

Campylobacter upsaliensis has been recognized as an emerging pathogen. However, little is known about its survival in the environment. To evaluate its survival capability, we estimated the reduction in viable counts of C. upsaliensis after aerobic exposure to starvation in phosphate-buffered saline (PBS), acidity (pH = 4.3), high osmolarity (4% NaCl), and dryness in wet pulp disks at different temperatures. Also, survival in dog feces and dog food at variable temperate was assessed.

Results

Campylobacter upsaliensis remained culturable under starvation for 4 days at 25 °C and for 10 weeks at 4 °C. C. upsaliensis was also recoverable after exposure to high osmolality for 9 days, dryness for 5 days, and acidity for 2 days, respectively. Similarly, C. upsaliensis survived in dog feces and dog food for several days at 25 °C and weeks at 4 °C. The survival capability of the organism was dependent on the water content, and also temperature. Notably, the tested C. upsaliensis strain was less resilient under all tested conditions than a C. jejuni strain used as a control. The findings showed that C. upsaliensis is able to survive under various environmental stresses, suggesting that it could pose a potential threat to public health.

Campylobacter jejuni in Different Canine Populations: Characteristics and Zoonotic Potential

With most epidemiological studies focused on poultry, dogs are often overlooked as a reservoir of Campylobacter, even though these animals maintain close daily contact with humans. The present study aimed to obtain a first insight into the presence and characteristics of Campylobacter spp. in different canine populations in Portugal, and to evaluate its zoonotic potential through genomic analysis. From a total of 125 rectal swabs collected from companion (n = 71) and hunting dogs (n = 54) living in two different settings, rural (n = 75) and urban (n = 50), 32 Campylobacter spp. isolates were obtained. Four different Campylobacter species were identified by Multiplex PCR and MALDI-TOF mass spectrometry, of which Campylobacter jejuni (n = 14, 44%) was overall the most frequently found species. Relevant resistance phenotypes were detected in C. jejuni, with 93% of the isolates being resistant to ciprofloxacin, 64% to tetracycline, and 57% to ampicillin, and three isolates being multi-drug-resistant. Comparison of the phenotypic and genotypic traits with human isolates from Portuguese patients revealed great similarity between both groups. Particularly relevant, the wgMLST analysis allowed the identification of isolates from human and dogs without any apparent epidemiological relationship, sharing high genetic proximity. Notwithstanding the limited sample size, considering the high genomic diversity of C. jejuni, the genetic overlap between human and dog strains observed in this study confirmed that the occurrence of this species in dogs is of public health concern, reinforcing the call for a One Health approach.

Prevalence of Campylobacter spp. in Raccoon Dogs and Badgers in Miyazaki Prefecture, Japan

A total of 55 samples of intestinal contents from 28 raccoon dogs (Nyctereutes procyonoides) and 27 badgers (Males anakuma) in Miyazaki prefecture, Japan, were examined for the presence of Campylobacter species. C. jejuni and C. upsaliensis were isolated from 3.6% (n = 1) and 75% (n = 21) of raccoon dogs, respectively. In contrast, no Campylobacter spp. was isolated from the badgers examined. The C. upsaliensis isolates were subjected to antimicrobial susceptibility testing against 8 antimicrobial agents. This revealed that most of the isolates from raccoon dogs were susceptible to the antimicrobial agents examined, whereas strains isolated from healthy dogs in Miyazaki prefecture, showed high rates of resistance. Virulence genes (flaA, cadF, ciaB, cdtA, cdtB, and cdtC) were present in the C. jejuni isolate from a raccoon dog, with the exception of flaB. By contrast, all these virulence genes examined were present in all C. upsaliensis strains isolated from raccoon dogs and dogs. The genetic diversity of those isolates based on the nucleotide sequences of 7 housekeeping genes (adk, aspA, atpA, glnA, glyA, pgi, tkt) was compared with that of C. upsaliensis strains isolated from dogs and strains selected randomly from humans and dogs deposited in the Campylobacter MLST database. The major cluster of raccoon dog strains was separated from both human and dog strains by phylogenetic tree analysis. These results suggest that raccoon dogs are a reservoir of C. upsaliensis and that isolates may represent a population different from that in humans and dogs. To our knowledge, this is the first study to have demonstrated a high prevalence of C. upsaliensis in raccoon dogs.

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.

Comparison of the Pathogenic Potential of Campylobacter jejuni, C. upsaliensis and C. helveticus and Limitations of Using Larvae of Galleria mellonella as an Infection Model

Campylobacter enteritis in humans is primarily associated with C. jejuni/coli infection. Other species cause campylobacteriosis relatively infrequently; while this could be attributed to bias in diagnostic methods, the pathogenicity of non-jejuni/coli Campylobacter spp. such as C. upsaliensis and C. helveticus (isolated from dogs and cats) is uncertain. Galleria mellonella larvae are suitable models of the mammalian innate immune system and have been applied to C. jejuni studies. This study compared the pathogenicity of C. jejuni, C. upsaliensis, and C. helveticus isolates. Larvae inoculated with either C. upsaliensis or C. helveticus showed significantly higher survival than those inoculated with C. jejuni. All three Campylobacter species induced indistinguishable histopathological changes in the larvae. C. jejuni could be isolated from inoculated larvae up to eight days post-inoculation whereas C. upsaliensis and C. helveticus could only be isolated in the first two days. There was a significant variation in the hazard rate between batches of larvae, in Campylobacter strains, and in biological replicates as random effects, and in species and bacterial dose as fixed effects. The Galleria model is applicable to other Campylobacter spp. as well as C. jejuni, but may be subject to significant variation with all Campylobacter species. While C. upsaliensis and C. helveticus cannot be considered non-pathogenic, they are significantly less pathogenic than C. jejuni.

Campylobacter upsaliensis isolated from a giant hepatic cyst

Campylobacter upsaliensis is an enteropathogenic bacterium in animals, and is also rarely isolated from humans, where it can cause enteritis and bacteremia. This report describes the first case of isolation of C. upsaliensis from an infected giant hepatic cyst. This bacterium could not be cultured from abscess punctuate in a usual Campylobacter-selection medium (charcoal cefoperazone deoxycholate agar medium), because of high concentration of cefoperazone as a selection agent. It could not identified by matrix-assisted laser desorption ionization-time of flight mass spectrum. Rather, it was identified as C. upsaliensis by whole genome sequencing, including by multilocus sequence typing.

Occurrence and Antimicrobial Resistance Profiles of Campylobacter jejuni, Campylobacter coli, and Campylobacter upsaliensis in Beef Cattle on Cow-Calf Operations in South Africa

This study investigated occurrence and antimicrobial resistance profiles of Campylobacter spp. isolates in beef cattle on five cow-calf operations in South Africa. A total of 537 fecal samples from adult beef cattle (n = 435) and rectal swabs from calves (n = 102) were screened for Campylobacter jejuni, Campylobacter coli, and Campylobacter upsaliensis by culture and polymerase chain reaction. Furthermore, 86 Campylobacter spp. isolates including 46 C. jejuni, 24 C. coli, and 16 C. upsaliensis were tested for antimicrobial resistance against a panel of 9 antimicrobials. Overall, Campylobacter spp. was detected in 29.7% of cattle. Among the 158 Campylobacter spp.-positive cattle, 61.8% carried C. jejuni, 25% carried C. coli, and 10% carried C. upsaliensis. Five animals (3.1%) had mixed infections: three cows carried C. jejuni and C. coli concurrently, one cow had both C. jejuni and C. upsaliensis, and one cow harbored C. coli and C. upsaliensis. Antimicrobial resistance profiling among 86 Campylobacter spp. isolates revealed that 52.3% of the isolates were resistant to one or more antimicrobials. Antimicrobial resistance was observed in 46.7% of C. jejuni isolates, 35.6% of C. coli, and 17.8% of C. upsaliensis. Thirty-six percent of isolates were resistant to clindamycin, 19.7% to nalidixic acid, 18.6% to tetracycline, and 17.4% to erythromycin. Lower resistance rates were recorded for azithromycin (8.1%), florfenicol (3.4%), gentamicin (4.8%), and telithromycin and ciprofloxacin (5.8%). Multidrug resistance (MDR) was observed in 32.5% of isolates. Significantly higher levels of MDR were detected among C. jejuni (36.9%) and C. coli (33.3%) isolates in comparison to C. upsaliensis (18.7%). Two main multiresistance patterns were detected: nalidixic acid/clindamycin (17.8%) and tetracycline/clindamycin (14.2%). To the best of our knowledge, this is the first study which has shown that beef cattle on cow-calf operations in South Africa constitute an important reservoir and a potential source of clinically relevant and antimicrobial resistant Campylobacter spp. strains.

Human campylobacteriosis: A public health concern of global importance

Campylobacter species are among the leading cause of bacterial foodborne and waterborne infections. In addition, Campylobacter is one of the major causative agent of bacterial gastrointestinal infections and the rise in the incidence of Campylobacter infections have been reported worldwide. Also, the emergence of some Campylobacter species as one of the main causative agent of diarrhea and the propensity of these bacteria species to resist the actions of antimicrobial agents; position them as a serious threat to the public health. This paper reviews Campylobacter pathogenicity, infections, isolation and diagnosis, their reservoirs, transmission pathways, epidemiology of Campylobacter outbreaks, prevention and treatment option, antibiotics resistance and control of antibiotics use.

Pathogenomics of Emerging Campylobacter Species

Campylobacter is among the four main causes of gastroenteritis worldwide and has increased in both developed and developing countries over the last 10 years. The vast majority of reported Campylobacter infections are caused by Campylobacter jejuni and, to a lesser extent, C. coli; however, the increasing recognition of other emerging Campylobacter pathogens is urgently demanding a better understanding of how these underestimated species cause disease, transmit, and evolve. In parallel to the enhanced clinical awareness of campylobacteriosis due to improved diagnostic protocols, the application of high-throughput sequencing has increased the number of whole-genome sequences available to dozens of strains of many emerging campylobacters. This has allowed for comprehensive comparative pathogenomic analyses for several species, such as C. fetus and C. concisus These studies have started to reveal the evolutionary forces shaping their genomes and have brought to light many genomic features related to pathogenicity in these neglected species, promoting the development of new tools and approaches relevant for clinical microbiology. Despite the need for additional characterization of genomic diversity in emerging campylobacters, the increasing body of literature describing pathogenomic studies on these species deserves to be discussed from an integrative perspective. This review compiles the current knowledge and highlights future work toward deepening our understanding about genome dynamics and the mechanisms governing the evolution of pathogenicity in emerging Campylobacter species, which is urgently needed to develop strategies to prevent or control the spread of these pathogens.

Gut microbiome alteration in MORDOR I: a community-randomized trial of mass azithromycin distribution

The MORDOR I trial1, conducted in Niger, Malawi and Tanzania, demonstrated that mass azithromycin distribution to preschool children reduced childhood mortality1. However, the large but simple trial design precluded determination of the mechanisms involved. Here we examined the gut microbiome of preschool children from 30 Nigerien communities randomized to either biannual azithromycin or placebo. Gut microbiome γ-diversity was not significantly altered (P = 0.08), but the relative abundances of two Campylobacter species, along with another 33 gut bacteria, were significantly reduced in children treated with azithromycin at the 24-month follow-up. Metagenomic analysis revealed functional differences in gut bacteria between treatment groups. Resistome analysis showed an increase in macrolide resistance gene expression in gut microbiota in communities treated with azithromycin (P = 0.004). These results suggest that prolonged mass azithromycin distribution to reduce childhood mortality reduces certain gut bacteria, including known pathogens, while selecting for antibiotic resistance.

Occurrence of Campylobacter species from broiler chickens and chicken meat in Malaysia

Campylobacter is reported as a major cause of foodborne illness worldwide. Consumption of contaminated chicken meat is considered a significant risk factor of Campylobacter infection in humans. This study investigated the occurrence of non-Campylobacter jejuni-Campylobacter coli, in broiler chickens (n = 210) and chicken meat (n = 109). The samples were collected from seven broiler chicken farms (n = 210 cloacal swabs), 11 markets (n = 84 chicken meat), and 5 supermarkets (n = 25 chicken meat) located in different districts of Selangor State. Campylobacter were isolated from cloacal swabs using the Cape Town Protocol and from meat samples using the method of Duffy et al. (2007) with some modifications for Campylobacter isolations which were reported effective in the isolation of non-C. jejuni-C. coli Campylobacter species. The isolates were identified by Gram staining for cellular morphology, wet mount for motility and biochemical tests. Confirmation of presumed Campylobacter isolates was carried out using multiplex PCR (mPCR). One hundred seven (107/210) or 50.9% and twenty-nine (29/109) or 26.6% of chickens and chicken meat samples respectively were positive for Campylobacter species. Among the Campylobacter isolates from chickens, C. jejuni was the most predominantly isolated species (69.5%), followed by C. coli (16.2%). Campylobacter fetus and C. upsaliensis were the non-C. jejuni-C. coli Campylobacter species isolated in this study, at 9.3% and 2.5% respectively. Overall, the findings indicated broiler chickens were colonized not only by the common Campylobacter species but also by other Campylobacter species. We found the Cape Town Protocol useful to detect the occurrence of non-C. jejuni-C. coli isolates in chickens.

Prevalence and risk factors associated with Campylobacter spp. occurrence in healthy dogs visiting four rural community veterinary clinics in South Africa

Reports on the occurrence of Campylobacter spp. in dogs in South Africa are non-existent. This study investigated the prevalence of Campylobacter spp. in 481 dogs visiting four rural community veterinary clinics in South Africa. Dogs were screened for Campylobacter spp. by culture and polymerase chain reaction (PCR), and logistic regression analysis was performed to assess the association between sex, clinic, breed and age and the occurrence of Campylobacter spp. in dogs. The prevalence of Campylobacter spp. was 41.50% (95% confidence interval [CI], 37.39% - 46.04%). Campylobacter jejuni, C. upsaliensis and C. coli were detected in 29.31% (95% CI, 25.42% - 33.54%), 13.10% (95% CI, 10.37% - 16.42%) and 5.41% (95% CI, 3.71% - 7.82%) of dogs, respectively. Dogs carrying more than one species of Campylobacter spp. accounted for 6.23% (95% CI, 4.40% - 8.78%). Campylobacter upsaliensis and C. jejuni were detected in 3.74% (95% CI, 2.37% - 5.86%), whereas C. coli and C. jejuni were found in 2.49% (95% CI, 1.42% - 4.34%) of dogs. Age and clinic were the risk factors significantly associated with Campylobacter spp. occurrence, while age, breed and clinic were predictors of C. jejuni carriage. Furthermore, age was the only risk factor associated with a higher likelihood of carrying C. upsaliensis. The prevalence of Campylobacter spp. C. jejuni and C. upsaliensis increased significantly as dogs grew older. In addition, the odds of carrying Campylobacter spp. were higher in the Staffordshire bull terrier breed compared to crossbreed dogs. In conclusion, this study shows that dogs visiting rural community veterinary clinics in South Africa are reservoirs of Campylobacter spp. and may be potential sources of Campylobacter spp. for humans living in close proximity of the dog populations under study.

Salmonella, Campylobacter, Clostridium difficile, and anti-microbial resistant Escherichia coli in the faeces of sympatric meso-mammals in southern Ontario, Canada

The role of free-ranging wildlife in the epidemiology of enteropathogens causing clinical illness in humans and domestic animals is unclear. Salmonella enterica and anti-microbial resistant bacteria have been detected in the faeces of raccoons (Procyon lotor), but little is known about the carriage of these bacteria in other sympatric meso-mammals. Our objectives were to: (a) report the prevalence of Salmonella and associated anti-microbial resistance, Campylobacter spp, Clostridium difficile, and anti-microbial resistant Escherichia coli in the faeces of striped skunks (Mephitis mephitis) and Virginia opossums (Didelphis virginiana) in southern Ontario; and (b) compare the prevalence of these bacteria in the faeces of these meso-mammal hosts with raccoons from a previously reported study. Faecal swabs were collected from striped skunks and Virginia opossums on five swine farms and five conservation areas from 2011 to 2013. Salmonella was detected in 41% (9/22) and 5% (5/95) of faecal swabs from Virginia opossums and striped skunks, respectively. None of the Salmonella serovars carried resistance to anti-microbials. The prevalence of Campylobacter spp., C. difficile, and anti-microbial resistant E. coli ranged from 6% to 22% in striped skunk and Virginia opossums. Using exact logistic regression, Salmonella was significantly more likely to be detected in faecal swabs of Virginia opossums than skunks and significantly less likely in faecal swabs from skunks than raccoons from a previously reported study. In addition, Campylobacter spp. was significantly more likely to be detected in raccoons than opossums. Salmonella Give was detected in 8/9 (89%) of Salmonella-positive Virginia opossum faecal swabs. Our results suggest that striped skunks and Virginia opossums have the potential to carry pathogenic enteric bacteria in their faeces. The high prevalence of Salmonella Give in Virginia opossum faecal swabs in this study as well as its common occurrence in other Virginia opossum studies throughout North America suggests Virginia opossums may be reservoirs of this serovar.

Detection and characterisation of canine astrovirus, canine parvovirus and canine papillomavirus in puppies using next generation sequencing

Gastroenteritis in young animals is a clinical presentation with many infectious and non- infectious aetiologies. We used next generation sequencing (NGS) to investigate the possible infectious causes of gastroenteritis in puppies from a dog kennel in Victoria, Australia. The near complete genome of a canine astrovirus was obtained from pooled faecal samples, and was found to be 94.7% identical with a canine astrovirus detected in the United Kingdom in 2012. The phylogenetic analysis of the capsid gene found similarities to those of canine astroviruses identified in Italy in 2005 and in UK and Hungary in 2012, but distant from that of a canine astrovirus previously identified in Australia in 2012. Thus, different serotypes of canine astrovirus are likely circulating in Australia. The close relationship to European astroviruses also suggested that there had been recent movements of ancestor canine astroviruses between Australia and Europe. NGS also detected other infections in the puppies including several canine papillomaviruses and a canine parvovirus (vaccine strain) as well as a very low level of campylobacter. Canine astrovirus was the probable cause of diarrhoea in these puppies, with the possible involvement of campylobacter bacteria. NGS was effective as a non-targeted method to determine the likely infectious cause of gastroenteritis.

Antimicrobial Resistance in Campylobacter Species: Mechanisms and Genomic Epidemiology

The Campylobacter genus is a large and diverse group of Gram-negative bacteria that are known to colonize humans and other mammals, birds, reptiles, and shellfish. While it is now recognized that several emerging Campylobacter species can be associated with human disease, two species, C. jejuni and C. coli, are responsible for the vast majority of bacterial gastroenteritis in humans worldwide. Infection with C. jejuni, in particular, has also been associated with a number of extragastrointestinal manifestations and autoimmune conditions, most notably Guillain-Barré syndrome. The antimicrobial drugs of choice for the treatment of severe Campylobacter infection include macrolides, such as erythromycin, clarithromycin, or azithromycin. Fluoroquinolones, such as ciprofloxacin, are also commonly used for empirical treatment of undiagnosed diarrheal disease. However, resistance to these and other classes of antimicrobial drugs is increasing and is a major public health problem. The US Centers for Disease Control and Prevention estimates that over 300,000 infections per year are caused by drug-resistant Campylobacter. In this chapter, we discuss the taxonomy of the Campylobacter genus, the clinical and global epidemiological aspects of Campylobacter infection, with an emphasis on C. jejuni and C. coli, and issues related to the treatment of infection and antimicrobial resistance mechanisms. We further discuss the use of next-generation sequencing for the detection and surveillance of antimicrobial resistance genes.

Pet-associated Campylobacteriosis: A persisting public health concern

Campylobacter is regarded as a leading cause of human bacterial gastroenteritis in the United States. We report on a case of laboratory-confirmed Campylobacter jejuni infection in the Commonwealth of Pennsylvania among members of a household living with a laboratory-confirmed but non-speciated Campylobacter-infected puppy. We describe an outbreak of likely dog-associated campylobacteriosis, the risk factors, potential routes of exposure and the clinical features in the exposed family members, which began shortly after exposure to the recently purchased dog. We also provide public health recommendations to prevent Campylobacter infections in veterinary care providers, pet owners and those planning to adopt pets in the future. Finally, this report underscores the importance of the One Health approach when public health responders, human and animal healthcare providers and clinical diagnostic laboratories are tasked with developing effective strategies when investigating, detecting and responding to zoonoses (diseases shared between animals and humans).

Oxidative and nitrosative stress defences of Helicobacter and Campylobacter species that counteract mammalian immunity

Helicobacter and Campylobacter species are Gram-negative microaerophilic host-associated heterotrophic bacteria that invade the digestive tract of humans and animals. Campylobacter jejuni is the major worldwide cause of foodborne gastroenteritis in humans, while Helicobacter pylori is ubiquitous in over half of the world's population causing gastric and duodenal ulcers. The colonisation of the gastrointestinal system by Helicobacter and Campylobacter relies on numerous cellular defences to sense the host environment and respond to adverse conditions, including those imposed by the host immunity. An important antimicrobial tool of the mammalian innate immune system is the generation of harmful oxidative and nitrosative stresses to which pathogens are exposed during phagocytosis. This review summarises the regulators, detoxifying enzymes and subversion mechanisms of Helicobacter and Campylobacter that ultimately promote the successful infection of humans.

Clinical relevance of infections with zoonotic and human oral species of Campylobacter

Genus Campylobacter has been recognized as a causative bacterial agent of animal and human diseases. Human Campylobacter infections have caused more concern. Campylobacters can be classified into two groups in terms of their original host: zoonotic and human oral species. The major zoonotic species are Campylobacter jejuni and Campylobacter coli, which mostly reside in the intestines of avian species and are transmitted to humans via consumption of contaminated poultry products, thus causing human gastroenteritis and other diseases as sequelae. The other campylobacters, human oral species, include C. concisus, C. showae, C. gracilis, C. ureolyticus, C. curvus, and C. rectus. These species are isolated from the oral cavity, natural colonization site, but have potential clinical relevance in the periodontal region to varying extent. Two species, C. jejuni and C. coli, are believed to be mainly associated with intestinal diseases, but recent studies suggested that oral Campylobacter species also play a significant role in intestinal diseases. This review offers an outline of the two Campylobacter groups (zoonotic and human oral), their virulence traits, and the associated illnesses including gastroenteritis.

Variation in the limit-of-detection of the ProSpecT Campylobacter microplate enzyme immunoassay in stools spiked with emerging Campylobacter species

Campylobacter enteritis in humans is primarily associated with C. jejuni/coli infection. The impact of other Campylobacter spp. is likely to be underestimated due to the bias of culture methods towards Campylobacter jejuni/coli diagnosis. Stool antigen tests are becoming increasingly popular and appear generally less species-specific. A review of independent studies of the ProSpecT® Campylobacter Microplate enzyme immunoassay (EIA) developed for C. jejuni/coli showed comparable diagnostic results to culture methods but the examination of non-jejuni/coli Campylobacter spp. was limited and the limit-of-detection (LOD), where reported, varied between studies. This study investigated LOD of EIA for Campylobacter upsaliensis, Campylobacter hyointestinalis and Campylobacter helveticus spiked in human stools. Multiple stools and Campylobacter isolates were used in three different concentrations (10(4)-10(9)CFU/ml) to reflect sample heterogeneity. All Campylobacter species evaluated were detectable by EIA. Multivariate analysis showed LOD varied between Campylobacter spp. and faecal consistency as fixed effects and individual faecal samples as random effects. EIA showed excellent performance in replicate testing for both within and between batches of reagents, in agreement between visual and spectrophotometric reading of results, and returned no discordance between the bacterial concentrations within independent dilution test runs (positive results with lower but not higher concentrations). This study shows how limitations in experimental procedures lead to an overestimation of consistency and uniformity of LOD for EIA that may not hold under routine use in diagnostic laboratories. Benefits and limitations for clinical practice and the influence on estimates of performance characteristics from detection of multiple Campylobacter spp. by EIA are discussed.

Antibiotic susceptibility pattern and genotyping of campylobacter species isolated from children suffering from gastroenteritis

PURPOSE

To study the prevalence and the antimicrobial resistance of campylobacter species isolated from children suffering from gastroenteritis .

MATERIALS AND METHODS

A total of 125 stool samples were collected from children with gastroenteritis. The identification of isolates was performed with conventional methods as well as with molecular methods based on 16SrRNA species-specific gene amplification by PCR and product analysis. Resistance pattern of the isolated strains was determined using agar dilution method.

RESULTS

Conventional methods including sodium hippurate hydrolysis revealed that 12 (9.6%) samples were positive for Campylobacter species. Ten out of 12 Campylobacter spp. were identified as Campylobacter jejuni and 2 as Campylobacter coli but PCR assay revealed that five samples only were positive for Campylobacter and all were C. jejuni. Antimicrobial susceptibility to 10 antimicrobials was performed and all isolates (five isolates of C. jejuni) were susceptible to chloramphenicol, gentamicin and amikacin but all were resistant to ceftriaxone.

CONCLUSION

PCR assay method allows reliable detection of C. jejuni. C. jejuni was the most prevalent Campylobacter species. Gentamicin, amikacin and chloramphenicol were the most effective antibiotic.

Multicenter evaluation of the BioFire FilmArray gastrointestinal panel for etiologic diagnosis of infectious gastroenteritis

The appropriate treatment and control of infectious gastroenteritis depend on the ability to rapidly detect the wide range of etiologic agents associated with the disease. Clinical laboratories currently utilize an array of different methodologies to test for bacterial, parasitic, and viral causes of gastroenteritis, a strategy that suffers from poor sensitivity, potentially long turnaround times, and complicated ordering practices and workflows. Additionally, there are limited or no testing methods routinely available for most diarrheagenic Escherichia coli strains, astroviruses, and sapoviruses. This study assessed the performance of the FilmArray Gastrointestinal (GI) Panel for the simultaneous detection of 22 different enteric pathogens directly from stool specimens: Campylobacter spp., Clostridium difficile (toxin A/B), Plesiomonas shigelloides, Salmonella spp., Vibrio spp., Vibrio cholerae, Yersinia enterocolitica, enteroaggregative E. coli, enteropathogenic E. coli, enterotoxigenic E. coli, Shiga-like toxin-producing E. coli (stx1 and stx2) (including specific detection of E. coli O157), Shigella spp./enteroinvasive E. coli, Cryptosporidium spp., Cyclospora cayetanensis, Entamoeba histolytica, Giardia lamblia, adenovirus F 40/41, astrovirus, norovirus GI/GII, rotavirus A, and sapovirus. Prospectively collected stool specimens (n = 1,556) were evaluated using the BioFire FilmArray GI Panel and tested with conventional stool culture and molecular methods for comparison. The FilmArray GI Panel sensitivity was 100% for 12/22 targets and ≥94.5% for an additional 7/22 targets. For the remaining three targets, sensitivity could not be calculated due to the low prevalences in this study. The FilmArray GI Panel specificity was ≥97.1% for all panel targets. The FilmArray GI Panel provides a comprehensive, rapid, and streamlined alternative to conventional methods for the etiologic diagnosis of infectious gastroenteritis in the laboratory setting. The potential advantages include improved performance parameters, a more extensive menu of pathogens, and a turnaround time of as short as 1 h.

Cj1386, an atypical hemin-binding protein, mediates hemin trafficking to KatA in Campylobacter jejuni

Catalase enzymes detoxify H2O2 by the dismutation of H2O2 into O2 and H2O through the use of hemin cofactors. While the structure and biochemical properties of catalase enzymes have been well characterized over many decades of research, it remained unclear how catalases acquire hemin. We have previously reported that Cj1386 is essential for ensuring proper hemin content in Campylobacter jejuni catalase (KatA) (A. Flint, Y. Q. Sun, and A. Stintzi, J Bacteriol 194: 334-345, 2012). In this report, an in-depth molecular characterization of Cj1386 was performed to elucidate the mechanistic details of this association. Coimmunoprecipitation assays revealed that KatA-Cj1386 transiently interact in vivo, and UV-visible spectroscopy demonstrated that purified Cj1386 protein binds hemin. Furthermore, hemin titration experiments determined that hemin binds to Cj1386 in a 1:1 ratio with hexacoordinate hemin binding. Mutagenesis of potential hemin-coordinating residues in Cj1386 showed that tyrosine 57 was essential for hemin coordination when Cj1386 was overexpressed in Escherichia coli. The importance of tyrosine 57 in hemin trafficking in vivo was confirmed by introducing the cj1386(Y57A) allele into a C. jejuni Δcj1386 mutant background. The cj1386(Y57A) mutation resulted in increased sensitivity toward H2O2 relative to the wild type, suggesting that KatA was not functional in this strain. In support of this finding, KatA immunoprecipitated from the Δcj1386+cj1386(Y57A) mutant had significantly reduced hemin content compared to that of the cj1386(WT) background. Overall, these findings indicate that Cj1386 is involved in directly trafficking hemin to KatA and that tyrosine 57 plays a key role in this function.

First case report of fatal sepsis due to Campylobacter upsaliensis

We encountered a rare case of severe fatal infection in a 70-year-old woman due to Campylobacter upsaliensis, identified by PCR amplification and sequencing analysis of the 16S rRNA gene using DNA extracted from the isolates. To our knowledge, fatal sepsis due to this organism has never been described to date.

Comprehensive genomic characterization of campylobacter genus reveals some underlying mechanisms for its genomic diversification

Campylobacter species.are phenotypically diverse in many aspects including host habitats and pathogenicities, which demands comprehensive characterization of the entire Campylobacter genus to study their underlying genetic diversification. Up to now, 34 Campylobacter strains have been sequenced and published in public databases, providing good opportunity to systemically analyze their genomic diversities. In this study, we first conducted genomic characterization, which includes genome-wide alignments, pan-genome analysis, and phylogenetic identification, to depict the genetic diversity of Campylobacter genus. Afterward, we improved the tetranucleotide usage pattern-based naïve Bayesian classifier to identify the abnormal composition fragments (ACFs, fragments with significantly different tetranucleotide frequency profiles from its genomic tetranucleotide frequency profiles) including horizontal gene transfers (HGTs) to explore the mechanisms for the genetic diversity of this organism. Finally, we analyzed the HGTs transferred via bacteriophage transductions. To our knowledge, this study is the first to use single nucleotide polymorphism information to construct liable microevolution phylogeny of 21 Campylobacter jejuni strains. Combined with the phylogeny of all the collected Campylobacter species based on genome-wide core gene information, comprehensive phylogenetic inference of all 34 Campylobacter organisms was determined. It was found that C. jejuni harbors a high fraction of ACFs possibly through intraspecies recombination, whereas other Campylobacter members possess numerous ACFs possibly via intragenus recombination. Furthermore, some Campylobacter strains have undergone significant ancient viral integration during their evolution process. The improved method is a powerful tool for bacterial genomic analysis. Moreover, the findings would provide useful information for future research on Campylobacter genus.

Mannose receptor, C type 1 contributes to bacterial uptake by placental trophoblast giant cells

During pregnancy, maternal immune function is strictly controlled and immune tolerance is induced. Trophoblast giant (TG) cells exhibit phagocytic activity and show macrophage-like activity against microorganisms in the placenta. However, details of molecular receptors and mechanisms for uptake by TG cells have not been clarified. In this study, we investigated the involvement of the mannose receptor, C type 1 (MRC1), in the uptake of the abortion-inducible bacterium Listeria monocytogenes and abortion-uninducible bacteria Bacillus subtilis and Escherichia coli by TG cells differentiated from a mouse trophoblast stem cell line in vitro. Knockdown of MRC1 inhibited the uptake of all of these bacteria, as did the blocking of MRC1 by MRC1 ligands. The uptake of bacteria by MRC1 delayed the maturation of phagolysosomes. These findings suggest that MRC1 plays an important role in the uptake of various bacteria by TG cells and may provide an opportunity for those bacteria to escape from phagosomes.

Comparative characterization of the virulence gene clusters (lipooligosaccharide [LOS] and capsular polysaccharide [CPS]) for Campylobacter coli, Campylobacter jejuni subsp. jejuni and related Campylobacter species

Campylobacter jejuni subsp. jejuni and Campylobacter coli are leading causes of gastroenteritis, with virulence linked to cell surface carbohydrate diversity. Although the associated gene clusters are well studied for C. jejuni subsp. jejuni, C. coli has been largely neglected. Here we provide comparative analysis of the lipooligosaccharide (LOS) and capsular polysaccharide (CPS) gene clusters, using genome and cluster sequence data for 36 C. coli strains, 67 C. jejuni subsp. jejuni strains and ten additional Campylobacter species. Similar to C. jejuni subsp. jejuni, C. coli showed high LOS/CPS gene diversity, with each cluster delineated into eight gene content classes. This diversity was predominantly due to extensive gene gain/loss, with the lateral transfer of genes likely occurring both within and between species and also between the LOS and CPS. Additional mechanisms responsible for LOS/CPS diversity included phase-variable homopolymeric repeats, gene duplication/inactivation, and possibly host environment selection pressure. Analyses also showed that (i) strains of C. coli and Campylobacter upsaliensis possessed genes homologous to the sialic acid genes implicated in the neurological disorder Guillain-Barré syndrome (GBS), and (ii) C. coli LOS classes were differentiated between bovine and poultry hosts, potentially aiding post infection source tracking.

Enteropathogenic bacteria in dogs and cats: diagnosis, epidemiology, treatment, and control

This report offers a consensus opinion on the diagnosis, epidemiology, treatment, and control of the primary enteropathogenic bacteria in dogs and cats, with an emphasis on Clostridium difficile, Clostridium perfringens, Campylobacter spp., Salmonella spp., and Escherichia coli associated with granulomatous colitis in Boxers. Veterinarians are challenged when attempting to diagnose animals with suspected bacterial-associated diarrhea because well-scrutinized practice guidelines that provide objective recommendations for implementing fecal testing are lacking. This problem is compounded by similar isolation rates for putative bacterial enteropathogens in animals with and without diarrhea, and by the lack of consensus among veterinary diagnostic laboratories as to which diagnostic assays should be utilized. Most bacterial enteropathogens are associated with self-limiting diarrhea, and injudicious administration of antimicrobials could be more harmful than beneficial. Salmonella and Campylobacter are well-documented zoonoses, but antimicrobial administration is not routinely advocated in uncomplicated cases and supportive therapy is recommended. Basic practices of isolation, use of appropriate protective equipment, and proper cleaning and disinfection are the mainstays of control. Handwashing with soap and water is preferred over use of alcohol-based hand sanitizers because spores of C. difficile and C. perfringens are alcohol-resistant, but susceptible to bleach (1:10 to 1:20 dilution of regular household bleach) and accelerated hydrogen peroxide. The implementation of practice guidelines in combination with the integration of validated molecular-based testing and conventional testing is pivotal if we are to optimize the identification and management of enteropathogenic bacteria in dogs and cats.

The clinical importance of emerging Campylobacter species

A growing number of Campylobacter species other than C. jejuni and C. coli have been recognized as emerging human and animal pathogens. Although C. jejuni continues to be the leading cause of bacterial gastroenteritis in humans worldwide, advances in molecular biology and development of innovative culture methodologies have led to the detection and isolation of a range of under-recognized and nutritionally fastidious Campylobacter spp., including C. concisus, C. upsaliensis and C. ureolyticus. These emerging Campylobacter spp. have been associated with a range of gastrointestinal diseases, particularly gastroenteritis, IBD and periodontitis. In some instances, infection of the gastrointestinal tract by these bacteria can progress to life-threatening extragastrointestinal diseases. Studies have shown that several emerging Campylobacter spp. have the ability to attach to and invade human intestinal epithelial cells and macrophages, damage intestinal barrier integrity, secrete toxins and strategically evade host immune responses. Members of the Campylobacter genus naturally colonize a wide range of hosts (including pets, farm animals and wild animals) and are frequently found in contaminated food products, which indicates that these bacteria are at risk of zoonotic transmission to humans. This Review presents the latest information on the role and clinical importance of emerging Campylobacter spp. in gastrointestinal health and disease.

Occurrence of fastidious Campylobacter spp. in fresh meat and poultry using an adapted cultural protocol

This study used an adapted cultural protocol for the recovery of fastidious species of Campylobacter, to gain a more accurate understanding of the diversity of Campylobacter populations in fresh meats. Chicken (n=185), pork (n=179) and beef (n=186) were collected from supermarkets and butchers throughout the Republic of Ireland. Samples were enriched in Campylobacter enrichment broth for 24h under an atmosphere of 2.5% O(2), 7% H(2), 10% CO(2), and 80.5% N(2). The enriched samples were then filtered onto non-selective Anaerobe Basal Agar supplemented with lysed horse blood using mixed ester filter membranes. Isolates were identified by both genus and species-specific PCR assays and biochemical testing. The incidence of campylobacters on beef (36%) was significantly higher than on pork (22%) or chicken (16%), and far exceeds previously reported prevalence levels. The method was successful in recovering 7 species of Campylobacter, including the fastidious spp. C. concisus and C. mucosalis, from chicken meat, and 10 species, including C. concisus, C. curvus, C. mucosalis, C. sputorum, and C. upsaliensis, from minced beef. The isolation of C. concisus and C. upsaliensis from meat in this study is of particular significance, due to their emerging clinical relevance. The results of this study confirm that the diversity of Campylobacter species on fresh meats is greater than previously reported and highlights the bias of cultural methods towards the recovery of C. jejuni.

Factors related toCampylobacterspp. carriage in client-owned dogs visiting veterinary clinics in a region of Ontario, Canada

From July 2008 until May 2009, 240 client-owned pet dogs from seven veterinary clinics in the Region of Waterloo, Ontario, Canada participated in a study to determine pet-related management factors that may be associated with the presence ofCampylobacterspp. in dogs. The prevalence ofCampylobacterspp. carriage in our study population of pet dogs was 22%, with 19% of the dogs positive forC. upsaliensis, and 3% positive forC. jejuni. A significant risk factor from multivariable logistic regression models for bothCampylobacterspp. andC. upsaliensiscarriage was having homemade cooked food as the dog's diet or added to its diet, and a significant sparing factor for both models was treatment with antibiotics in the previous month. Increasing age of the dog decreased the odds ofCampylobacterspp. andC. upsaliensiscarriage. Based on the high prevalence ofCampylobacter, and specificallyC. upsaliensis, further research concerning pet dogs as a risk factor for campylobacteriosis in humans is warranted.

Campylobacter bacteremia: clinical characteristics, incidence, and outcome over 23 years

Campylobacter is a very rare cause of bloodstream infection, although it has been found relatively frequently in patients infected with human immunodeficiency virus (HIV). The impact of highly active antiretroviral therapy (HAART) and new forms of immunosuppression on the incidence of Campylobacter bacteremia has not been sufficiently assessed. In this study we analyzed the incidence and microbiologic and clinical characteristics of Campylobacter bacteremia over 23 years.We reviewed the clinical records of all patients who had Campylobacter bacteremia from 1985 to 2007. Available strains were reidentified using universal polymerase chain reaction (PCR).During the study period, there were 71 episodes of Campylobacter bacteremia in 63 patients (0.24% of all bloodstream infections), and the incidence remained stable (mean, 0.06/1000 admissions per year and 0.47/100,000 inhabitants per year). Median age was 52 years (interquartile range, 31.25-72.5 yr), and 82% of patients were male. The underlying conditions included liver disease (21/64, 32.8%), HIV infection (15/64, 23.4%), malignancy (7/64, 10.9%), solid organ transplantation (2/64, 3%), hypogammaglobulinemia (10/64, 15.6%), and other (18/64, 31.2%). Twelve patients shared more than 1 underlying condition. Campylobacter bacteremia was community acquired in 81% of the episodes. The origin of the bloodstream infection was abdominal (43.5%), primary (26%), or extraintestinal (31%: respiratory 15%, cellulitis 4.8%, urinary 8%, other 3%). C jejuni was recovered in 66% of cases, C fetus in 19%, and C coli in 12%.Universal PCR was performed on 14 available strains. Molecular and conventional identification matched in 8 isolates. In contrast, molecular methods classified as C fetus (n = 2) and C jejuni (n = 1) 3 strains formerly identified only to genus level as Campylobacter species. In another 3 isolates, molecular identification was not consistent with the phenotypic identification (C fetus identified as C jejuni).Complications appeared in 23.9% of patients. Quinolone resistance was observed in 50% of the isolates. Only 37.8% of patients received appropriate empirical therapy. Mortality was 16.4%, although it was higher in HIV-infected patients than uninfected patients (33% vs. 10%; p = 0.04), in cases of hospital-acquired Campylobacter bacteremia compared with community-acquired cases (38.5% vs. 9.4%; p = 0.02), and in the presence of complications compared with patients without complications (100% vs. 0%; p < 0.001). The incidence of recurrence was 5% (3 patients with humoral immunodeficiency). There was a higher proportion of HIV-infected patients among patients with Campylobacter bacteremia in the pre-HAART era (1985-1996) than in the HAART era (1997-2007)-27.5% (11/40) vs. 14.3% (4/28)-although the difference was not statistically significant. Debilitating diseases such as chronic obstructive pulmonary disease emerged as predisposing conditions in the HAART era (0% before HAART era vs. 14.3% in HAART era; p = 0.032).Campylobacter bacteremia is no longer a significant disease of HIV-positive patients on HAART, but often affects other immunocompromised patients as well. Campylobacter bacteremia has an extraintestinal origin in as many as 31% of cases, and humoral immunodeficiency must be sought in patients with recurrent episodes. Quinolones should not be considered for empirical therapy.

Contribution of the multidrug efflux transporter CmeABC to antibiotic resistance in different Campylobacter species

CmeABC, a multidrug efflux system in Campylobacter jejuni, plays an important role in the resistance to different antimicrobials and toxic compounds. Although this efflux system has been well characterized in C. jejuni and to a less extent in C. coli, it is unknown if CmeABC homologs are functional in other Campylobacter spp. In this study, the cmeABC homologs were identified and functionally characterized in five Campylobacter species including C. jejuni, C. coli, C. lari, C. upsaliensis, and C. fetus. Our results indicated that cmeABC is present in all five Campylobacter spp. and the genomic organization of this efflux operon is similar among the Campylobacter spp. Insertional mutagenesis of cmeB increased the susceptibilities of all the five Campylobacter spp. to structurally diverse antimicrobials. Together, these results indicated that the CmeABC efflux system is conserved at both the genomic and functional levels in all five Campylobacter spp. examined in this study, further highlighting the significant role of CmeABC in Campylobacter pathobiology.

Fibronectin enhances Campylobacter fetus interaction with extracellular matrix components and INT 407 cells

Campylobacter fetus is a recognized pathogen of cattle and sheep that can also infect humans. No adhesins specific for C. fetus have to date been identified; however, bacterial attachment is essential to establish an infecting population. Scanning electron microscopy revealed C. fetus attachment to the serosal surface of human colonic biopsy explants, a location consistent with the presence of the extracellular matrix (ECM). To determine whether the ECM mediated C. fetus adherence, 7 C. fetus strains were assessed in a solid-phase binding assay for their ability to bind to immobilized ECM components. Of the ECM components assayed, adherence to fibronectin was noted for all strains. Attachment to ECM components was neither correlated with S-layer expression nor with cell-surface hydrophobicity. Ligand immunoblots, however, identified the S-layer protein as a major site of fibronectin binding, and modified ECM binding assays revealed that soluble fibronectin significantly enhanced the attachment of S-layer-expressing C. fetus strains to other ECM components. Soluble fibronectin also increased C. fetus adherence to INT 407 cells. This adherence was inhibited when INT 407 cells were incubated with synthetic peptides containing an RGD sequence, indicating that integrin receptors were involved in fibronectin-mediated attachment. Together, this data suggests that C. fetus can bind to immobilized fibronectin and use soluble fibronectin to enhance attachment to other ECM components and intestinal epithelial cells. In vivo, fibronectin would promote bacterial adherence, thereby, contributing to the initial interaction of C. fetus with mucosal and submucosal surfaces.

Comparative analysis of human and canine Campylobacter upsaliensis isolates by amplified fragment length polymorphism

Human (n = 33) and canine (n = 53) Campylobacter upsaliensis isolates from seven countries were genotyped by a new amplified fragment length polymorphism method. We observed 100% typeability and high overall diversity. The majority of human strains (23/33) clustered separately from canine strains, indicating that dogs may not be the main source of human infection.

Bacterial gut infections

Infections of the bowel as a result of bacterial enteropathogens are one of the most common medical problems. The use of novel molecular biology techniques and the recent development of new antimicrobial drugs and vaccines are helping us to identify, understand, treat and prevent these infections.

Genetic relatedness within the genus Campylobacter inferred from rpoB sequences

The genus Campylobacter comprises 17 species, some of which are important animal and human pathogens. To gain more insight into the genetic relatedness of this genus and to improve the molecular tools available for diagnosis, a universal sequencing approach was established for the gene encoding the beta-subunit of RNA polymerase (rpoB) for the genus Campylobacter. A total of 59 strains, including the type strains of currently recognized species as well as field isolates, were investigated in the study. A primer set specific for Campylobacter species enabled straightforward amplification and sequencing of a 530 bp fragment of the rpoB gene. The 16S rRNA gene sequences of all of the strains were determined in parallel. A good congruence was obtained between 16S rRNA and rpoB gene sequence-based trees within the genus Campylobacter. The branching of the rpoB tree was similar to that of the 16S rRNA gene tree, even though a few discrepancies were observed for certain species. The resolution of the rpoB gene within the genus Campylobacter was generally much higher than that of the 16S rRNA gene sequence, resulting in a clear separation of most species and even some subspecies. The universally applicable amplification and sequencing approach for partial rpoB gene sequence determination provides a powerful tool for DNA sequence-based discrimination of Campylobacter species.