Isolation, identification and subtyping of Campylobacter: Where to from here?

Occurrence of Campylobacter in Faeces, Livers and Carcasses of Wild Boars Hunted in Tuscany (Italy) and Evaluation of MALDI-TOF MS for the Identification of Campylobacter Species

A total of 193 wild boars hunted in Tuscany, an Italian region with a high presence of wild ungulates, were examined to assess the occurrence of Campylobacter species in faeces, bile, liver and carcasses, with the aim of clarifying their contribution to human infection through the food chain. Campylobacter spp. were found in 44.56% of the animals, 42.62% of the faecal samples, 18.18% of the carcass samples, 4.81% of the liver tissues and 1.97% of the bile samples. The Campylobacter species genotypically identified were C. coli, C. lanienae, C. jejuni and C. hyointestinalis. The prevalent species transpired to be C. coli and C. lanienae, which were isolated from all the matrices; C. jejuni was present in faeces and liver, while C. hyointestinalis only in faeces. Identification was carried out by matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS) on 66 out of 100 isolates identified genotypically, and the technique yielded unsatisfactory results in the case of C. lanienae, which is responsible for sporadic human disease cases. The level of Campylobacter spp. contamination of meat and liver underlines the need to provide appropriate food safety information to hunters and consumers.

Metagenomic Strain-Typing Combined with Isolate Sequencing Provides Increased Resolution of the Genetic Diversity of Campylobacter jejuni Carriage in Wild Birds

As the world's leading cause of human gastro-enteritis, the food- and waterborne pathogen Campylobacter needs to be intensively monitored through a One Health approach. Particularly, wild birds have been hypothesized to contribute to the spread of human clinical recurring C. jejuni genotypes across several countries. A major concern in studying epidemiological dynamics is resolving the large genomic diversity of strains circulating in the environment and various reservoirs, challenging to achieve with isolation techniques. Here, we applied a passive-filtration method to obtain isolates and in parallel recovered genotypes from metagenomic sequencing data from associated filter sweeps. For genotyping mixed strains, a reference-based computational workflow to predict allelic profiles of nine extended-MLST loci was utilized. We validated the pipeline by sequencing artificial mixtures of C. jejuni strains and observed the highest prediction accuracy when including obtained isolates as references. By analyzing metagenomic samples, we were able to detect over 20% additional genetic diversity and observed an over 50% increase in the potential to connect genotypes across wild-bird samples. With an optimized filtration method and a computational approach for genotyping strain mixtures, we provide the foundation for future studies assessing C. jejuni diversity in environmental and clinical settings at improved throughput and resolution.

Campylobacter bilis sp. nov., isolated from chickens with spotty liver disease

A novel species of Campylobacter was isolated from bile samples of chickens with spotty liver disease in Australia, making it the second novel species isolated from chickens with the disease, after Campylobacter hepaticus was isolated and described in 2016. Six independently derived isolates were obtained. They were Gram-stain-negative, microaerobic, catalase-positive, oxidase-positive and urease-negative. Unlike most other species of the genus Campylobacter, more than half of the tested strains of this novel species hydrolysed hippurate and most of them could not reduce nitrate. Distinct from C. hepaticus, many of the isolates were sensitive to 2,3,5-triphenyltetrazolium chloride (0.04%) and metronidazole (4 mg ml^-1), and all strains were sensitive to nalidixic acid. Phylogenetic analysis using 16S rRNA and hsp60 gene sequences demonstrated that the strains formed a robust clade that was clearly distinct from recognized Campylobacter species. Whole genome sequence analysis of the strains showed that the average nucleotide identity and the genome blast distance phylogeny values compared to other Campylobacter species were less than 86 and 66%, respectively, which are below the cut-off values generally recognized for isolates of the same species. The genome of the novel species has a DNA G+C content of 30.6 mol%, while that of C. hepaticus is 27.9 mol%. Electron microscopy showed that the cells were spiral-shaped, with bipolar unsheathed flagella. The protein spectra generated from matrix-assisted laser desorption/ionization time of flight analysis demonstrated that they are different from the most closely related Campylobacter species. These data indicate that the isolates belong to a novel Campylobacter species, for which the name Campylobacter bilis sp. nov. is proposed. The type strain is VicNov18^T (=ATCC TSD-231^T=NCTC 14611^T).

Construction, expression and purification of a novel CadF-based multiepitope antigen and its immunogenic polyclonal antibody specific to Campylobacter jejuni and Campylobacter coli

Campylobacteriosis is a disease in humans caused by the infection from Campylobacter spp. Human cases are mainly due to Campylobacter jejuni, although C. coli can cause gastroenteritis in humans as well. The bacteria are commensal in chicken tract and can be contaminated into chicken products during processing. Obviously, detecting reagents such as a specific antibody is essential for the development of immune-based detection methods for C. jejuni or C. coli. In this study, in silico techniques were used to design a chimeric recombinant antigen, named multiepitope antigen (MEA), for the production of specific polyclonal antibody. To design MEA polypeptide based on C. jejuni fibronectin-binding protein or CadF, four conserved and unique antigenic peptides were identified and fused together directly. The C. jejuni CadF-based MEA polypeptide fused with two single six-histidine tags at both C- and N-terminal ends was expressed under Escherichia coli expression system. The recombinant MEA was successfully produced and purified by Ni-NTA resin with a high satisfactory yield. Indirect ELISA results showed that anti-MEA polyclonal antibody derived from rabbit serum had a titer of 16,000, indicating high antigenicity of MEA polypeptide. Dot blot results also confirmed that the produced anti-MEA antibody could specifically recognize both C. jejuni and C. coli whole cells as expected while there was no cross-reactivity to non-Campylobacter spp. tested in this study.

Isolation, Molecular Detection, and Risk Factors of Campylobacter Infection From Companion Dogs

Background: Campylobacter is an organism that is usually associated with diarrhea in pet animals and humans, as well as other domestic, wild, and laboratory animals. Objective: The aim of the present survey was the isolation, molecular detection, and risk factors of Campylobacter infection from companion dogs referred to the Veterinary Hospital of Ahvaz district, the South-West of Iran. Materials and Methods: Rectal swabs were examined by culture and polymerase chain reaction (PCR) methods from 122 companion dogs (52 diarrheic and 70 clinically healthy). Several risk factors were reviewed, including age, gender, breed, nutrition status, and lifestyle. Results: The results showed that only five samples (4.1%) were positive for Campylobacter spp. in the culture method. Campylobacter spp. was detected in 18 out of 122 dogs by the PCR, yielding an overall prevalence of 14.8%. The most prevalent species of Campylobacter among the referred dogs were C. coli (38.89%) and C. jejuni (33.33%). A lower prevalence was found for C. upsaliensis (11.11%) and C. lari (5.55%). Concurrent infections were observed in two cases of C. upsaliensis + C. lari (5.55%) and C. coli + C. lari (5.55%). No significant difference was noted between healthy (11.43%) and diarrheic (19.23%) dogs (P>0.05). Eventually, age, gender, breed, nutrition status, and lifestyle had no significant effect on Campylobacter infection (P>0.05). Conclusion: Although the prevalence of Campylobacter was moderate in the dog population of Ahvaz district, these bacteria can constitute a public health hazard because of the frequent presence of Campylobacter species in the feces.

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.

Evaluation of Two Multiplex PCR-High-Resolution Melt Curve Analysis Methods for Differentiation of Campylobacter jejuni and Campylobacter coli Intraspecies

Campylobacter infection is a common cause of bacterial gastroenteritis in humans and remains a significant global public health issue. The capability of two multiplex PCR (mPCR)-high-resolution melt (HRM) curve analysis methods (i.e., mPCR1-HRM and mPCR2-HRM) to detect and differentiate 24 poultry isolates and three reference strains of Campylobacter jejuni and Campylobacter coli was investigated. Campylobacter jejuni and C. coli were successfully differentiated in both assays, but the differentiation power of mPCR2-HRM targeting the cadF gene was found superior to that of mPCR1-HRM targeting the gpsA gene or a hypothetical protein gene. However, higher intraspecies variation within C. coli and C. jejuni isolates was detected in mPCR1-HRM when compared with mPCR2-HRM. Both assays were rapid and required minimum interpretation skills for discrimination between and within Campylobacter species when using HRM curve analysis software.

Isolation of emerging Campylobacter species in working farm dogs and their frozen home-killed raw meat diets

We applied 7 culture methods to 50 working farm dog fecal samples and 6 methods to 50 frozen home-killed raw meat diet samples to optimize recovery of a wide range of Campylobacter spp. Culture methods combined filtration, enrichment broths, and agars at 37°C and 42°C in conventional and hydrogen-enriched microaerobic atmospheres. Overall, a prevalence of 62% (31 of 50) and 6% (3 of 50) was detected in dog and meat samples, respectively, based on Campylobacter genus PCR. A total of 356 Campylobacter spp. isolates were recovered from dogs, with successful isolation by individual methods ranging from 2 to 25 dogs. The species detected most commonly were C. upsaliensis and C. jejuni, and less commonly C. coli and C. lari. Species isolated that are rarely reported from dogs included C. rectus, C. lari subsp. concheus, C. volucris, and Helicobacter winghamensis. Six isolates from dogs positive by Campylobacter genus PCR were confirmed, using 16S rRNA sequencing, as Arcobacter cryaerophilus (1) and Arcobacter butzleri (5). C. jejuni multi-locus sequence typing results revealed a diversity of sequence types in working dogs, with several uncommonly reported from other C. jejuni sources in New Zealand. Overall, 20 isolates from 3 meat samples were positive by Campylobacter genus PCR; 1 meat sample was positive for C. jejuni, 1 for C. rectus, and 1 isolate was subsequently identified as A. butzleri. The method using Campylobacter enrichment broth in a hydrogen-enriched environment on nonselective agar resulted in significantly reduced recovery of Campylobacter spp. from both sample types.

High-Throughput flaA Short Variable Region Sequencing to Assess Campylobacter Diversity in Fecal Samples From Birds

Current approach to identify sources of human pathogens is largely dependent on the cultivation and isolation of target bacteria. For rapid pathogen source identification, culture-independent strain typing method is necessary. In this study, we designed new primer set that broadly covers flaA short variable region (SVR) of various Campylobacter species, and applied the flaA SVR sequencing method to examine the diversity of Campylobacter spp. in geese fecal samples (n = 16) with and without bacteria cultivation. Twenty-three Campylobacter strains isolated from the 16 geese fecal samples were grouped similarly by conventional flaA restriction fragment length polymorphism (RFLP) method and by the flaA SVR sequencing method, but higher discriminant power was observed in the flaA SVR sequencing approach. For culture-independent flaA SVR sequencing analysis, we developed and optimized the sequence data analysis pipeline to identify as many genotypes as possible, while minimizing the detection of genotypes generated by sequencing errors. By using this pipeline, 51,629 high-quality flaA sequence reads were clustered into 16 operational taxonomic units (=genotypes) by using 98% sequence similarity and >50 sequence duplicates. Almost all flaA genotypes obtained by culture-dependent method were also identified by culture-independent flaA SVR MiSeq sequencing method. In addition, more flaA genotypes were identified probably due to high throughput nature of the MiSeq sequencing. These results suggest that the flaA SVR sequencing could be used to analyze the diversity of Campylobacter spp. without bacteria isolation. This method is promising to rapidly identify potential sources of Campylobacter pathogens.

New Identification of Three or More Campylobacter Species on the Basis of a Degenerate PCR-RFLP Method Targeting gyrB Gene

This method was aimed targeting more Campylobacter species than conventional PCR-based identifications. They generally use species-specific primers focusing on clinically common species like C. jejuni, resulting in failure to recognize other species. We made the PCR-based identification more flexible using degenerate primers and DdeI- and MboI-separately used RFLP assay, which were designed on the basis of gyrB nucleotide sequence data of 14 Campylobacter species including C. jejuni, C. coli, and C. fetus. Ninety-four clinical isolates from patients with Campylobacter gastroenteritis and 13 biochemically identified C. fetus were used for its evaluation. In consequence, this method succeeded in identifying C. jejuni, C. coli, and C. fetus with tentative sensitivity (93.4-98.0%) and specificity (89.0-99.0%). According to our data-based analysis, the primers can possibly target other related species including Helicobacter and Arcobacter. This method may be a universal identification for Campylobacter and related organisms and would provide an alternative identification in clinical microbiology.

Simultaneous Identification of Campylobacter jejuni, Campylobacter coli, and Campylobacter lari with SmartCycler-Based Multiplex Quantitative Polymerase Chain Reaction

BACKGROUND

Consumption of Campylobacter contaminated food or water is a leading cause of human acute gastroenteritis. Campylobacter jejuni, Campylobacter coli, and Campylobacter lari account for over 95% of total Campylobacter infections. A multiplex quantitative polymerase chain reaction (qPCR) for simultaneous identification of C. jejuni, C. coli, and C. lari was developed for use with the SmartCycler II system.

MATERIALS AND METHODS

We evaluated and combined previously described primers and probes for Campylobacter detection, designed a new internal amplification control, and optimized the multiplex qPCR for the detection of C. jejuni, C. coli, and C. lari.

RESULTS

This method was 100% specific when tested against a panel of 32 target Campylobacter strains and 31 non-Campylobacter reference strains. Furthermore, there was no cross-reactivity with seven strains from four nontarget Campylobacter species. The amplification efficiency of each target in this multiplex qPCR was over 90%, and each coefficient of linearity was greater than 0.99. With artificially mixed genomic DNA, this method detected as few as two, three, and two genome copies of C. jejuni, C. coli, and C. lari, respectively. This method was also able to detect these three Campylobacter species in artificially contaminated milk with a sensitivity of five spiked cells of each target per reaction.

CONCLUSION

The three Campylobacter targets were simultaneously identified using artificially mixed genomic DNA and spiked raw milk. This SmartCycler-based multiplex qPCR is a rapid, specific, and sensitive method to identify C. jejuni, C. coli, and C. lari.

A novel real-time PCR assay for quantitative detection of Campylobacter fetus based on ribosomal sequences

Background

Campylobacter fetus is a pathogen of major concern for animal and human health. The species shows a great intraspecific variation, with three subspecies: C. fetus subsp. fetus, C. fetus subsp. venerealis, and C. fetus subsp. testudinum. Campylobacter fetus fetus affects a broad range of hosts and induces abortion in sheep and cows. Campylobacter fetus venerealis is restricted to cattle and causes the endemic disease bovine genital campylobacteriosis, which triggers reproductive problems and is responsible for major economic losses. Campylobacter fetus testudinum has been proposed recently based on genetically divergent strains isolated from reptiles and humans. Both C. fetus fetus and C. fetus testudinum are opportunistic pathogens for immune-compromised humans. Biochemical tests remain as the gold standard for identifying C. fetus but the fastidious growing requirements and the lack of reliability and reproducibility of some biochemical tests motivated the development of molecular diagnostic tools. These methods have been successfully tested on bovine isolates but fail to detect some genetically divergent strains isolated from other hosts. The aim of the present study was to develop a highly specific molecular assay to identify and quantify C. fetus strains.

Results

We developed a highly sensitive real-time PCR assay that targets a unique region of the 16S rRNA gene. This assay successfully detected all C. fetus strains, including those that were negative for the cstA gene-based assay used as a standard for molecular C. fetus identification. The assay showed high specificity and absence of cross-reactivity with other bacterial species. The analytical testing of the assay was determined using a standard curve. The assay demonstrated a wide dynamic range between 10² and 107 genome copies per reaction, and a good reproducibility with small intra- and inter-assay variability.

Conclusions

The possibility to characterize samples in a rapid, sensitive and reproducible way makes this assay a good option to establish a new standard in molecular identification and quantification of C. fetus species.

Electronic supplementary material

The online version of this article (doi:10.1186/s12917-016-0913-3) contains supplementary material, which is available to authorized users.

Campylobacter-Associated Diseases in Animals

Campylobacter includes a group of genetically diverse species causing a range of diseases in animals and humans. The bacterium is frequently associated with two economically important and epidemiologically distinct reproductive diseases in ruminants: enzootic infectious infertility in cattle owing to Campylobacter fetus subsp. venerealis and abortions in sheep, goats, and cattle. Septic abortion, usually epizootic in sheep, has been historically associated with C. fetus subsp. fetus and to a lesser extent with Campylobacter jejuni. However, there has been a dramatic species shift in the etiology of Campylobacter abortions in recent years: C. jejuni has now replaced C. fetus subsp. fetus as the predominant cause of sheep abortion in the United States, which appears to be driven primarily by clonal expansion of a hypervirulent tetracycline-resistant C. jejuni clone. Here we provide a review on the recent advances in understanding the pathobiology of Campylobacter infections in animals, with an emphasis on the diseases in ruminants, covering epidemiology, pathogenesis, genomics, and control measures.

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.

Impact of changing from staining to culture techniques on detection rates of Campylobacter spp. in routine stool samples in Chile

BACKGROUND

Campylobacter is a leading cause of bacterial gastroenteritis, but sensitive diagnostic methods such as culture are expensive and often not available in resource limited settings. Therefore, direct staining techniques have been developed as a practical and economical alternative. We analyzed the impact of replacing Campylobacter staining with culture for routine stool examinations in a private hospital in Chile.

METHODS

From January to April 2014, a total of 750 consecutive stool samples were examined in parallel by Hucker stain and Campylobacter culture. Isolation rates of Campylobacter were determined and the performance of staining was evaluated against culture as the gold standard. Besides, isolation rates of Campylobacter and other enteric pathogens were compared to those of past years.

RESULTS

Campylobacter was isolated by culture in 46 of 750 (6.1 %) stool samples. Direct staining only identified three samples as Campylobacter positive and reached sensitivity and specificity values of 6.5 and 100 %, respectively. In comparison to staining-based detection rates of previous years, we observed a significant increase of Campylobacter cases in our patients.

CONCLUSION

Direct staining technique for Campylobacter had a very low sensitivity compared to culture. Staining methods might lead to a high rate of false negative results and an underestimation of the importance of campylobacteriosis. With the inclusion of Campylobacter culture, this pathogen became a leading cause of intestinal infection in our patient population.

Temporal variation in the prevalence and species richness of Campylobacter spp. in a prairie watershed impacted by urban and agricultural mixed inputs

Campylobacter spp. are a substantial cause of gastroenteritis worldwide. Human infection can result from ingestion of contaminated food or water from a variety of sources, including the consumption of fresh produce that is contaminated with the pathogen via the use of contaminated irrigation water. Using molecular methods, we investigated the occurrence of Campylobacter in the Qu’Appelle River watershed, an important source of irrigation water for vegetable producers in southern Saskatchewan, Canada. Water samples were collected from 7 sampling sites from April to September 2009 (145 samples), and from 5 sampling sites from May to October 2013 (116 samples). Campylobacter was detected in 57% and 16% of the samples collected in 2009 and 2013, respectively. Campylobacter detection was highest in May and June for both sampling years. In 2009, the predominant species were Campylobacter lari and Campylobacter jejuni, with prevalences of 84% and 41%, respectively. Other Campylobacter spp. were detected less frequently. Only C. lari was detected in 2013. The results in 2009 demonstrate the species richness of Campylobacter in water sources within the watershed. The occurrence of Campylobacter in the study area also underscores the importance of monitoring irrigation water used to irrigate fresh produce from a public health prospective.

Chicken, beams, and Campylobacter: rapid differentiation of foodborne bacteria via vibrational spectroscopy and MALDI-mass spectrometry

Campylobacter species are one of the main causes of food poisoning worldwide. Despite the availability of established culturing and molecular techniques, due to the fastidious nature of these microorganisms, simultaneous detection and species differentiation still remains challenging. This study focused on the differentiation of eleven Campylobacter strains from six species, using Fourier transform infrared (FT-IR) and Raman spectroscopies, together with matrix-assisted laser desorption ionisation-time of flight-mass spectrometry (MALDI-TOF-MS), as physicochemical approaches for generating biochemical fingerprints. Cluster analysis of data from each of the three analytical approaches provided clear differentiation of each Campylobacter species, which was generally in agreement with a phylogenetic tree based on 16S rRNA gene sequences. Notably, although C. fetus subspecies fetus and venerealis are phylogenetically very closely related, using FT-IR and MALDI-TOF-MS data these subspecies were readily differentiated based on differences in the lipid (2920 and 2851 cm(-1)) and fingerprint regions (1500-500 cm(-1)) of the FT-IR spectra, and the 500-2000 m/z region of the MALDI-TOF-MS data. A finding that was further investigated with targeted lipidomics using liquid chromatography-mass spectrometry (LC-MS). Our results demonstrate that such metabolomics approaches combined with molecular biology techniques may provide critical information and knowledge related to the risk factors, virulence, and understanding of the distribution and transmission routes associated with different strains of foodborne Campylobacter spp.

Comparative analysis of antimicrobial resistance and genetic diversity of Campylobacter from broilers slaughtered in Poland

In the current study, the relationship of Campylobacter jejuni and Campylobacter coli strains isolated at slaughter was investigated using comparative analysis of antimicrobial resistance (AMR), virulence gene (VG) and PFGE profiling. A total of 254 Campylobacter isolates from poultry caeca and corresponding carcasses, including 139 C. jejuni and 115 C. coli strains were tested. The most prevalent resistance profiles observed in C. jejuni were ciprofloxacin, nalidixic acid and tetracycline (46 out of 139, 33.1% isolates) as well as ciprofloxacin, nalidixic acid, tetracycline and streptomycin among C. coli strains (34 out of 115, 29.6%). Multi-resistance was found more frequently among C. coli than C. jejuni (P<0.05). The presence of 11 virulence genes exhibited 19 different VG profiles in Campylobacter isolates tested. All Campylobacter strains were classified into 154 different PFGE types. Among them, 56 profiles (28 C. jejuni and 28 C. coli) were common for at least two isolates including 9 clusters covering from 4 to 9 strains. Campylobacter composite types generated by a combination of 154 PFGE types, 10 AMR profiles and 19 VG patterns divided 178 distinct types with 95% similarity. The majority of the composite profiles (76 for C. jejuni and 58 for C. coli; 75.3% in total) included only one bacterial isolate. Furthermore, 11 pairs of C. jejuni and 12 pairs of C. coli from caeca and the corresponding carcasses isolated from the same places possessed the identical PFGE, AMR and VG patterns. This study demonstrated that C. jejuni and C. coli isolated from poultry in Poland showed to have a high genetic diversity and a weak clonal population structure. However, the composite analysis revealed a strong evidence for cross-contamination of chicken carcasses during the slaughter process. Additionally, our results confirm that Campylobacter may easily contaminate poultry carcasses at slaughter process and spread around country. More than half of Campylobacter strains tested (50.4%) were resistant to at least two classes of antimicrobials, i.e. quinolones and tetracyclines, which may cause a public health risk.

Molecular mechanisms of quinolone, macrolide, and tetracycline resistance among Campylobacter isolates from initial stages of broiler production

The aim of this study was to investigate the resistance mechanisms of quinolones, macrolides and tetracycline in campylobacter isolates from grandparent and parent broiler breeders in Spain. Twenty-six isolates were investigated for quinolone resistance, three isolates for macrolide resistance and 39 for tetracycline resistance. All of the quinolone-resistant isolates possessed the mutation Thr86Ile in the quinolone resistance-determining region of gyrA and one isolate possessed the mutation Pro104Ser. Only one Campylobacter coli population (defined by restriction fragment length polymorphism-polymerase chain reaction of flaA and pulsed field gel electrophoresis) was resistant to erythromycin, and the mutation A2075G (23S rDNA) was responsible for macrolide resistance. The tetO gene was found in all of the tetracycline-resistant isolates. Twenty-two out of the 39 isolates investigated by Southern blot possessed chromosomic location of tetO and 17 were located on plasmids. Most of the plasmids with tetO were of around 60 kb and conjugation was demonstrated in a selection of them. In conclusion, we showed that Thr86Ile is highly prevalent in quinolone-resistant isolates as well as mutation A2075G in macrolide-resistant isolates of poultry origin. More variability was found for tetO. The possibility of horizontal transmission of tetO among campylobacter isolates is also an issue of concern in public health.

Same-day subtyping of Campylobacter jejuni and C. coli isolates by use of multiplex ligation-dependent probe amplification-binary typing

Campylobacteriosis is the most commonly reported form of human bacterial gastroenteritis in the world. Sound identification of infectious sources requires subtyping, but the most widely used methods have turnaround times measured in days and require specialist equipment and skills. A multiplex ligation-dependent probe amplification-binary typing (MBiT) assay was developed for subtyping Campylobacter jejuni and Campylobacter coli. It was tested on 245 isolates, including recent isolates from Belgium and New Zealand, and compared to multilocus sequence typing (MLST). When used in an outbreak setting, MBiT identified the predominant genotype and possible additional cases days before pulsed-field gel electrophoresis (PFGE) results were available. MBiT was more discriminatory than MLST and, being a single assay with results produced within 6 h, was more rapid and cost-effective than both MLST and PFGE. In addition, MBiT requires only basic molecular biology equipment and skills.

Campylobacter corcagiensis sp. nov., isolated from faeces of captive lion-tailed macaques (Macaca silenus)

An investigation of the prevalence of Campylobacter ureolyticus in a variety of animals led to the identification of the strain CIT 045(T), in the faeces of captive lion-tailed macaques (Macaca silenus). Originally, believed to be Campylobacter ureolyticus based on the colony morphology and positive urease test, analysis of 16S rRNA and hsp60 gene sequences of this isolate revealed that the strain differs significantly from other species of the genus Campylobacter described to date. Species-specific primers for 16S rRNA and hsp60 genes were designed and used to identify two additional strains isolated from faeces samples from other macaques. Nucleotide sequence analysis of the 16S rRNA and hsp60 genes revealed ≤95% and ≤82  % sequence similarity to recognized species of the genus Campylobacter respectively. All three isolates formed a distinct group within the genus Campylobacter based on their 16S rRNA and hsp60 sequences and matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) profiles. The unique species status was further supported by phenotypic characteristics of the isolates. All isolates were found to be oxidase-, catalase- and urease-positive, they grew well at 37 °C and 42 °C and produced H2S on TSI (triple-sugar iron) and SIM (sulfide indole motility) media. The name Campylobacter corcagiensis sp. nov. is proposed for this novel species, with the strain CIT 045(T) as the type strain CIT 045(T) ( = LMG 27932(T), CCUG 64942(T)).