Isolation of Arcobacter species from animal feces

Investigation and characterization of Aliarcobacter spp. isolated from cattle slaughterhouse in Türkiye

Aliarcobacter spp. have been isolated from numerous food products at retail and from animal carcasses and feces at slaughter. The objectives of this study were as follows: (i) to isolate Aliarcobacter species from different slaughterhouses' samples and (ii) to detect genetic diversity, antibiotic resistance, biofilm ability, and putative virulence gene profiles of the isolates. A molecular investigation of antibiotic resistance and virulence factors was also conducted using polymerase chain reaction (PCR). Among 150 samples, a total of 22 (14.6%) Aliarcobacter spp. isolates were obtained, with varying levels of antibiotic resistance observed. The genes tetO, tetW, and gyrA were detected in 0%, 31.8%, and 27.2% of the isolates, respectively. All isolates were resistant to ampicillin, rifampin, and erythromycin, while tetracycline was found to be the most effective antibiotic, with 81.8% of the isolates showing susceptibility to it. All isolates (100%) harbored more than one of the nine putative virulence genes tested, with 18.1% of isolates carrying more than three. Regarding biofilm formation, 7 (31.8%) and 4 (18.1%) isolates were found to form strong and moderate biofilms, respectively, while one (4.5%) isolate was classified as a weak biofilm producer. ERIC-PCR band patterns suggested that the isolated Aliarcobacter spp. from slaughterhouses had different sources of contamination. These findings highlight the potential risk posed by pathogenic and multidrug-resistant Aliarcobacter spp. in food and the need for control measures throughout the food chain to prevent the spread of these strains. The results indicate that foods of animal origin and cattle slaughterhouses are significant sources of antimicrobial resistant Aliarcobacter.

Diversity and Distribution of Microbial Communities Associated with Reef Corals of the Malay Peninsula

Coral-associated bacteria play critical roles in the regulation of coral health and function. Environmental perturbations that alter the bacterial community structure can render the coral holobiont more susceptible and less resilient to disease. Understanding the natural variation of the coral microbiome across space and host species provides a baseline that can be used to distinguish shifts in community structure. Using a 16S rRNA gene metabarcoding approach, this study examines bacterial community structure across three scleractinian coral hosts. Our results show that corals of three regions-eastern and western Peninsular Malaysia and Singapore-host distinct bacterial communities; despite these differences, we were able to identify a core microbiome shared across all three species. This core microbiome was also present in samples previously collected in Thailand, suggesting that these core microbes play an important role in promoting and maintaining host health. For example, several have been identified as dimethylsulfoniopropionate (DMSP) metabolizers that have roles in sulfur cycling and the suppression of bacterial pathogens. Pachyseris speciosa has the most variable microbiome, followed by Porites lutea, with the composition of the Diploastrea heliopora microbiome the least variable throughout all locations. Microbial taxa associated with each region or site are likely shaped by local environmental conditions. Taken together, host identity is a major driver of differences in microbial community structure, while environmental heterogeneity shapes communities at finer scales.

The Prevalence of Aliarcobacter Species in the Fecal Microbiota of Farm Animals and Potential Effective Agents for Their Treatment: A Review of the Past Decade

There is an endless demand for livestock-originated food, so it is necessary to elucidate the hazard points for livestock breeding. Pathogens are one of the hazard points that threaten the biosecurity of farm-animal breeding and public health. As a potential foodborne pathogen, Aliarcobacter is a member of the intestinal microbiota of farm animals with and without diarrhea. Aliarcobacter spp. are capable of colonizing livestock intestines and are transmitted through the feces. Hence, they endanger slaughterhouses and milk products with fecal contamination. They also have other, rarer, vertical and horizontal transmission routes, including the offspring that abort in farm animals. Gastrointestinal symptoms and abort cases demonstrate potential financial losses to the industry. Viewed from this perspective, the global circulation of farm-animal products is a significant route for zoonotic agents, including Aliarcobacter. In the last decade, worldwide prevalence of Aliarcobacter in fecal samples has ranged from 0.8% in Italy to 100% in Turkey. Furthermore, antibiotic resistance is recognized as a new type of environmental pollutant and has become a hot topic in animal breeding and the food industry. Increasing antibiotic resistance has become a significant problem impacting productivity. The increase in antimicrobial resistance rates in Aliarcobacter is caused by the misuse of antimicrobial drugs in livestock animals, leading to the acquiring of resistance genes from other bacteria, as well as mutations in current resistance genes. The most resistant strains are A. butzleri, A. cryaerophilus, and A. skirrowii. This review analyzes recent findings from the past decade on the prevalence of Aliarcobacter in the intestinal microbiota and the current effective antibiotics against Aliarcobacter. The paper also highlights that A. cryaerophilus and A. skirrowii are found frequently in diarrheal feces, indicating that Aliarcobacter should be studied further in livestock diarrheal diseases. Moreover, Aliarcobacter-infected farm animals can be treated with only a limited number of antibiotics, such as enrofloxacin, doxycycline, oxytetracycline, and gentamicin.

A Review on the Prevalence of Arcobacter in Aquatic Environments

Arcobacter is an emerging pathogen that is associated with human and animal diseases. Since its first introduction in 1991, 33 Arcobacter species have been identified. Studies have reported that with the presence of Arcobacter in environmental water bodies, animals, and humans, a possibility of its transmission via water and food makes it a potential waterborne and foodborne pathogen. Therefore, this review article focuses on the general characteristics of Arcobacter, including its pathogenicity, antimicrobial resistance, methods of detection by cultivation and molecular techniques, and its presence in water, fecal samples, and animal products worldwide. These detection methods include conventional culture methods, and rapid and accurate Arcobacter identification at the species level, using quantitative polymerase chain reaction (qPCR) and multiplex PCR. Arcobacter has been identified worldwide from feces of various hosts, such as humans, cattle, pigs, sheep, horses, dogs, poultry, and swine, and also from meat, dairy products, carcasses, buccal cavity, and cloacal swabs. Furthermore, Arcobacter has been detected in groundwater, river water, wastewater (influent and effluent), canals, treated drinking water, spring water, and seawater. Hence, we propose that understanding the prevalence of Arcobacter in environmental water and fecal-source samples and its infection of humans and animals will contribute to a better strategy to control and prevent the survival and growth of the bacteria.

Prevalence, virulence genes and anti­microbial resistance of Arcobacter isolates from animal meat in Iran

Arcobacter spp. are food-borne and zoonotic entero-pathogens. Obtaining information in relation to antimicrobial resistance helps us for utilisation of an appropriate agent for the treatment of Arcobacter infections. This study aimed to investigate the prevalence, antimicrobial resistance and virulence factors in animal raw meat in Iran. The samples were collected from cattle (n=80), sheep (n=80), goats (n=80), camels (n=80), and buffaloes (n=60) from Khuzestan (n=110), Isfahan (n=80), Gilan (n=110) and Chaharmahal and Bakhtiari (n=80) provinces. Arcobacter isolates of meat samples were isolated, investigated by PCR method. The antibiotic resistance was also investigated. All isolates were screened for 6 virulence genes: cadF, ciaB, cj1349, Mvin, pldA and tlyA by PCR assays. The results showed that the prevalence of Arcobacter species had no significant difference among provinces and animals (P>0.05), so that positive samples were 1.25%, 1.25%, and 0.9% in Isfafhan, Chaharmahal and Bakhtiari, and Gilan, respectively. Virulence genes were observed for A. butzleri species (n=3, 100%). The results showed that Arcobacter spp. were resistant to streptomycin (100%), tetracycline (100%) and vancomycin (100%), but were susceptible to azithromycin (33.33%). In sum, the different regions of the Iran had a relative incidence of 1% for Arcobacter spp. The species showed a resistance of 100% for streptomycin, tetracycline and vancomycin. These findings could help to identify Arcobacter spp. and select the best agent against infection in case of Arcobacter infection in animals.

Prevalence, antimicrobial susceptibility and virulence gene profiles of Arcobacter species isolated from human stool samples, foods of animal origin, ready-to-eat salad mixes and environmental water

Background

Members of the genus Arcobacter are considered as emerging zoonotic food and waterborne pathogens that cause gastroenteritis and bacteremia in humans. However, the potential risk that Arcobacter species pose to public health remains unassessed in various countries, including Baltic states. Therefore, the aim of this study was to determine the prevalence, antimicrobial susceptibility and presence of putative virulence genes of Arcobacter isolates recovered from humans, food products and environmental water in Lithuania.

Results

A total of 1862 samples were collected and examined from 2018 to 2020 in the city of Kaunas. Overall, 11.2% (n = 208) of the samples were positive for the presence of Arcobacter spp. The highest prevalence was detected in chicken meat (36%), followed by environmental water (28.1%), raw cow milk (25%), ready-to-eat salad mixes (7.1%) and human stool (1.7%). A. butzleri was the most frequently isolated species (n = 192; 92.3%), followed by A. cryaerophilus (n = 16; 7.7%). Arcobacter spp. antimicrobial susceptibility testing revealed unimodally distributed aggregated minimal inhibitory concentrations (MICs) for gentamicin, tetracycline, ciprofloxacin, ampicillin and erythromycin. However, a bimodal distribution for azithromycin was found with 96.2% of determined MICs above the epidemiological cut-off value (ECOFF) defined for Campylobacter jejuni (0.25 µg/ml). Majority of the Arcobacter isolates (n = 187; 89.9%) showed high susceptibility to ciprofloxacin with MICs below or equal to the ECOFF value of 0.5 µg/ml. The putative virulence genes cadF (100%), ciaB (100%), cj1349 (99%), tlyA (99%), mviN (97.9%) and pldA (95.8%) were the predominant genes detected among A. butzleri isolates. In contrast, the mviN and ciaB genes were present in all, whereas cj1349 (12.5%), tlyA (25%) and hecA (12.5%) were only detected in few A. cryaerophilus isolates.

Conclusions

Our results demonstrate that food products and environmental water in Lithuania are frequently contaminated with Arcobacter spp. that carry multiple putative virulence genes. Furthermore, A. butzleri were isolated from 1.7% of inpatients. Fluoroquinolones and aminoglycosides were found to be more effective against Arcobacter in comparison to other antimicrobial agents. However, further studies are needed to determine the pathogenic mechanisms and factors that facilitate the spread of Arcobacter infections.

Occurrence and Antimicrobial Resistance of Arcobacter spp. Recovered from Aquatic Environments

Arcobacter spp. are emerging waterborne and foodborne zoonotic pathogens responsible for gastroenteritis in humans. In this work, we evaluated the occurrence and the antimicrobial resistance profile of Arcobacter isolates recovered from different aquatic sources. Besides, we searched for Arcobacter spp. in seaweeds and the corresponding seawater samples. Bacteriological and molecular methods applied to 100 samples led to the isolation of 28 Arcobacter isolates from 27 samples. The highest prevalence was detected in rivers followed by artificial ponds, streams, well waters, and spring waters. Seaweeds contained a higher percentage of Arcobacter than the corresponding seawater samples. The isolates were identified as Arcobacter butzleri (96.4%) and Arcobacter cryaerophilus (3.6%). All the isolates showed a multi-drug resistance profile, being resistant to at least three different classes of antibiotics. Molecular analysis of genetic determinants responsible for tetracycline resistance in nine randomly chosen isolates revealed the presence of tetO and/or tetW. This work confirms the occurrence and the continuous emergence of antibiotic-resistant Arcobacter strains in environmental samples; also, the presence of quinolone-resistant Arcobacter spp. in aquatic sources used for water supply and irrigation represents a potential risk for human health.

Occurrence and Antibiotic Resistance of Arcobacter Species Isolates from Poultry in Tunisia

ABSTRACT

Arcobacter is considered an emergent foodborne enteropathogen. Despite the high prevalence of this genus in poultry, the occurrence of Arcobacter spp. contamination in Tunisia remains unclear. The objectives of this study were (i) to isolate Arcobacter species (A. butzleri and A. cryaerophilus) by the culture method from different species of raw poultry meat, (ii) to verify the isolates by multiplex PCR (m-PCR) assay and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and (iii) to determine the antibiotic resistance profiles of the isolates. A total of 250 poultry product samples (149 chicken and 101 turkey) were collected from various supermarkets in Sfax. The samples consisted of breasts, wings, legs, and neck skins. The overall isolation frequency of Arcobacter spp. was 10.4%. Arcobacter spp. were found in 13.42% of the chicken samples and in 5.49% of the turkey samples. All the acquired isolates were subject to detailed confirmation with subsequent species classification using m-PCR and MALDI-TOF MS. A. butzleri was found in 22 samples (84.61%) and A. cryaerophilus in 4 samples (15.38%). Thus, m-PCR and MALDI-TOF MS were able to detect A. butzleri significantly better than the conventional method (χ2 = 49.1 and P < 0.001). Arcobacter was isolated from poultry in every season, at contamination levels of 30.76, 23.07, 19.23, and 26.92% in summer, spring, autumn, and winter, respectively. The disk diffusion method was used to determine the susceptibility of Arcobacter isolates to six antimicrobial drugs. All A. butzleri isolates (n = 24) were significantly resistant to erythromycin (P = 0.0015), ampicillin (P = 0.001), and ciprofloxacin (P = 0.05). All tested A. cryaerophilus strains (n = 4) were susceptible to ampicillin, gentamicin, and amoxicillin-clavulanic acid. Multidrug resistance was observed in 83% of the Arcobacter spp. isolates. Our study detected Arcobacter spp. in Tunisian poultry; because of their multidrug resistance, these species may constitute a public health problem.

HIGHLIGHTS

Isolation of Arcobacter spp. and identification of isolates by multiplex PCR from various domestic poultry and wild avian species

Purpose

The purpose of the present study was to determine the extent and seasonal prevalence of Arcobacter spp. in domestic poultry and wild birds in the Kars region of Turkey using multiplex polymerase chain reaction (m-PCR).

Methods

In this study, 1570 samples were collected from domestic poultry and wild avian species. The numbers of collected samples were as follows: 182 fecal samples from chickens, geese, and turkeys from family farms in the Kars region in Turkey; 1089 cloacal swab samples from chickens, geese, ducks, turkeys, and quails from family farms in this region; and 299 fecal samples from wild pigeons, crows, and owls in the same region.

Results

Arcobacter spp. were isolated from 17.43%, 35.77%, 3.63%, 6.87%, and 3.33% of the cloacal swab samples obtained from geese, ducks, chickens, turkeys, and quails, respectively. In the stool samples, Arcobacter spp. were isolated from 9.62%, 13.33%, and 4% of chicken, goose, and turkey samples, respectively. In wild birds, the isolation rates of Arcobacter spp. were 6.6%, 12.15%, and 0% in pigeons, crows, and owls, respectively. Using m-PCR, among 171 Arcobacter spp. isolates obtained from poultry and wild birds, 67, 78, 24, and 2 were identified as Arcobacter cryaerophilus, Arcobacter butzleri, Arcobacter skirrowii, and Arcobacter cibarius, respectively.

Conclusions

Both poultry and wild avian species exhibited variable rates of Arcobacter species positivity. The presence of Arcobacter spp. in the digestive tracts of healthy poultry and wild birds may serve as a potential reservoir for the dissemination of these microbes in the environment and their transmission to other animals and humans.

Aliarcobacter butzleri from Water Poultry: Insights into Antimicrobial Resistance, Virulence and Heavy Metal Resistance

Aliarcobacter butzleri is the most prevalent Aliarcobacter species and has been isolated from a wide variety of sources. This species is an emerging foodborne and zoonotic pathogen because the bacteria can be transmitted by contaminated food or water and can cause acute enteritis in humans. Currently, there is no database to identify antimicrobial/heavy metal resistance and virulence-associated genes specific for A. butzleri. The aim of this study was to investigate the antimicrobial susceptibility and resistance profile of two A. butzleri isolates from Muscovy ducks (Cairina moschata) reared on a water poultry farm in Thuringia, Germany, and to create a database to fill this capability gap. The taxonomic classification revealed that the isolates belong to the Aliarcobacter gen. nov. as A. butzleri comb. nov. The antibiotic susceptibility was determined using the gradient strip method. While one of the isolates was resistant to five antibiotics, the other isolate was resistant to only two antibiotics. The presence of antimicrobial/heavy metal resistance genes and virulence determinants was determined using two custom-made databases. The custom-made databases identified a large repertoire of potential resistance and virulence-associated genes. This study provides the first resistance and virulence determinants database for A. butzleri.

Real-time quantitative PCR assay development and application for assessment of agricultural surface water and various fecal matter for prevalence of Aliarcobacter faecis and Aliarcobacter lanthieri

BACKGROUND

Aliarcobacter faecis and Aliarcobacter lanthieri are recently identified as emerging human and animal pathogens. In this paper, we demonstrate the development and optimization of two direct DNA-based quantitative real-time PCR assays using species-specific oligonucleotide primer pairs derived from rpoB and gyrA genes for A. faecis and A. lanthieri, respectively. Initially, the specificity of primers and amplicon size of each target reference strain was verified and confirmed by melt curve analysis. Standard curves were developed with a minimum quantification limit of 100 cells mL^- 1 or g^- 1 obtained using known quantities of spiked A. faecis and A. lanthieri reference strains in autoclaved agricultural surface water and dairy cow manure samples.

RESULTS

Each species-specific qPCR assay was validated and applied to determine the rate of prevalence and quantify the total number of cells of each target species in natural surface waters of an agriculturally-dominant and non-agricultural reference watershed. In addition, the prevalence and densities were determined for human and various animal (e.g., dogs, cats, dairy cow, and poultry) fecal samples. Overall, the prevalence of A. faecis for surface water and feces was 21 and 28%, respectively. The maximum A. faecis concentration for water and feces was 2.3 × 10⁷ cells 100 mL^{- 1} and 1.2 × 10⁷ cells g^- 1, respectively. A. lanthieri was detected at a lower frequency (2%) with a maximum concentration in surface water of 4.2 × 10⁵ cells 100 mL^- 1; fecal samples had a prevalence and maximum density of 10% and 2.0 × 10⁶ cells g^- 1, respectively.

CONCLUSIONS

The results indicate that the occurrence of these species in agricultural surface water is potentially due to fecal contamination of water from livestock, human, or wildlife as both species were detected in fecal samples. The new real-time qPCR assays can facilitate rapid and accurate detection in < 3 h to quantify total numbers of A. faecis and A. lanthieri cells present in various complex environmental samples.

Prevalence and antimicrobial susceptibility of Arcobacter species in human stool samples derived from out- and inpatients: the prospective German Arcobacter prevalence study Arcopath

Background

Arcobacter species, particularly A. butzleri, but also A. cryaerophilus constitute emerging pathogens causing gastroenteritis in humans. However, isolation of Arcobacter may often fail during routine diagnostic procedures due to the lack of standard protocols. Furthermore, defined breakpoints for the interpretation of antimicrobial susceptibilities of Arcobacter are missing. Hence, reliable epidemiological data of human Arcobacter infections are scarce and lacking for Germany. We therefore performed a 13-month prospective Arcobacter prevalence study in German patients.

Results

A total of 4636 human stool samples was included and Arcobacter spp. were identified from 0.85% of specimens in 3884 outpatients and from 0.40% of specimens in 752 hospitalized patients. Overall, A. butzleri was the most prevalent species (n = 24; 67%), followed by A. cryaerophilus (n = 10; 28%) and A. lanthieri (n = 2; 6%). Whereas A. butzleri, A. cryaerophilus and A. lanthieri were identified in outpatients, only A. butzleri could be isolated from samples of hospitalized patients. Antimicrobial susceptibility testing of Arcobacter isolates revealed high susceptibilities to ciprofloxacin, whereas bimodal distributions of MICs were observed for azithromycin and ampicillin.

Conclusions

In summary, Arcobacter including A. butzleri, A. cryaerophilus and A. lanthieri could be isolated in 0.85% of German outpatients and ciprofloxacin rather than other antibiotics might be appropriate for antibiotic treatment of infections. Further epidemiological studies are needed, however, to provide a sufficient risk assessment of Arcobacter infections in humans.

Large genetic diversity of Arcobacter butzleri isolated from raw milk in Southern Italy

Arcobacter butzleri is a zoonotic foodborne pathogen able to cause enteric and extraintestinal diseases. Its occurrence in foodstuff is well recognized worldwide but data on its presence in foods from Southern Italy are scarce. In this study the results on the occurrence and genotyping of Arcobacter spp. in bulk milk samples collected in Southern Italy are reported. Out of 484 samples, 64 (13.2%) resulted positive for the presence of Arcobacter spp. Using Real Time PCR but as few as 31.2% of these samples turned out as positive by using the cultural method, showing an overall prevalence of 4.1%. All isolates were identified as A. cryaerophilus using the biochemical identification whilst the sequencing of the atpA gene revealed that all the isolates were A. butzleri. Among the confirmed isolates, 16 different Sequence Types (ST) were identified using the Multi Locus Sequence Typing (MLST), 14 (87.5%) of which were previously unreported. Our survey reveals the presence of A. butzleri in bulk tank milk from Southern Italy and highlights the discrepancy between the two approaches used both for the detection (i.e., real time PCR vs cultural method) and the identification (i.e., biochemical test vs aptA sequencing) of Arcobacter spp In addition, a large genetic diversity among the isolates was detected and this makes the identification of source of the infections very challenging in outbreaks investigation.

Identification of virulence and antibiotic resistance factors in Arcobacter butzleri isolated from bovine milk by Whole Genome Sequencing

Arcobacter butzleri is a pathogenic aerobic bacterium responsible for diarrhea and septicemia in humans. It is frequently isolated from food products of animal origin, including milk and dairy products. To data, few reports are currently available on the genetic characteristics and virulence profiles of A. butzleri. The aim of this study was to investigate the genetic diversity and to characterize the virulence and antibiotic resistance profiles of 10 A. butzleri strains isolated from bovine milk samples by Whole Genome Sequence (WGS). Multi-Locus Sequence Typing (MLST) revealed that three isolates belonged to the ST66, two to the ST420 and the remaining five strains to the ST627, ST629, ST630, ST633 and ST637, respectively. The 100% of the strains carried cadF, pldA, ciaB, cj1349, mviN and tlyA virulence factors genes; 60% iroE; 50% irgA; 10% hecB. Resistome prediction showed a multidrug resistance: 100% of isolates resulted resistant to fluoroquinolones and tetracycline; 90% of strains to rifampicin and cephalosporins and a minor percentage to other antibiotics. Furthermore, the 50% of strains harbored four mutations in Mycobacterium tuberculosis katG gene conferring resistance to isoniazid. The study provided interesting data on the virulence characteristics and on the genetic endowment related to the antimicrobial resistance of A. butzleri isolates from milk. The determination of the STs also added information concerning the genetic variability of this microorganism. To date, a very limited number of studies have been published on the typing of A. butzleri using WGS, so this paper proposes an innovative methodological approach that allows a rapid and complete characterization of pathogenic microorganisms.

Filling the gaps in clinical proteomics: a do-it-yourself guide for the identification of the emerging pathogen Arcobacter by matrix-assisted laser desorption ionization-time of flight mass spectrometry

Arcobacters are considered emerging gastrointestinal pathogens. Rapid, reliable and species-specific identification of these bacteria is important. Biochemical tests commonly yield negative or variable results. Molecular methods prove more reliable but are time consuming and lack specificity. Matrix assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is a fast, cheap and robust technique that has revolutionized genus and species identification in clinical microbiology. The performance of an in vitro diagnostic (RUO) spectral database of MALDI-TOF MS for the identification of human clinically relevant Arcobacter isolates was validated and compared to an in house created Reference Spectral database (RS) containing a representative set of deposited Arcobacter strains of zoonotic interest. A challenge panel of clinical, human and veterinary, unique Campylobacteraceae strains was used to test accuracy. Using direct colony transfer, sensitivity with RS was significantly better than with RUO for A. butzleri and A. cryaerophilus identification (100% and 92% versus 74% and 16%). For A. skirrowii, sensitivity remained low (21% versus 0%). Reanalysis using formic acid overlay (on-target extraction) augmented sensitivity for the latter species to 64%. Specificity of RS database remained excellent without any misidentifications of human clinical strains including Campylobacter fetus and C. jejuni/coli. The use of an enriched database for MALDI-TOF MS identification of Arcobacter spp. of human interest produced high-confidence identifications to species level resulting in a significantly improved sensitivity with conservation of excellent specificity. Misidentifications, which can have therapeutic and public health consequences, were not encountered.

Quantitative real-time PCR-based assessment of tile drainage management influences on bacterial pathogens in tile drainage and groundwater

This study compared the impact of controlled tile drainage (CD) and freely draining (FD) systems on the prevalence and quantitative real-time PCR-based enumeration of four major pathogens including Arcobacter butzleri, Campylobacter jejuni, Campylobacter coli, and Helicobacter pylori in tile- and groundwater following a fall liquid swine manure (LSM) application on clay loam field plots. Although the prevalence of all target pathogens were detected in CD and FD systems, the loads of A. butzleri, C. jejuni, and C. coli were significantly lower in CD tile-water (p<0.05), in relation to FD tile-water. However, concentrations of A. butzleri were significantly greater in CD than FD tile-water (p<0.05). In shallow groundwater (1.2m depth), concentrations of A. butzleri, C. coli, and H. pylori showed no significant difference between CD and FD plots, while C. jejuni concentrations were significantly higher in FD plots (p<0.05). No impact of CD on the H. pylori was observed since quantitative detection in tile- and groundwater was scarce. Although speculative, H. pylori occurrence may have been related to the application of municipal biosolids four years prior to the LSM experiment. Overall, CD can be used to help minimize off-field export of pathogens into surface waters following manure applications to land, thereby reducing waterborne pathogen exposure risks to humans.

Arcobacter: an emerging food-borne zoonotic pathogen, its public health concerns and advances in diagnosis and control - a comprehensive review

Arcobacter has emerged as an important food-borne zoonotic pathogen, causing sometimes serious infections in humans and animals. Newer species of Arcobacter are being incessantly emerging (presently 25 species have been identified) with novel information on the evolutionary mechanisms and genetic diversity among different Arcobacter species. These have been reported from chickens, domestic animals (cattle, pigs, sheep, horses, dogs), reptiles (lizards, snakes and chelonians), meat (poultry, pork, goat, lamb, beef, rabbit), vegetables and from humans in different countries. Arcobacters are implicated as causative agents of diarrhea, mastitis and abortion in animals, while causing bacteremia, endocarditis, peritonitis, gastroenteritis and diarrhea in humans. Three species including A. butzleri, A. cryaerophilus and A. skirrowii are predominantly associated with clinical conditions. Arcobacters are primarily transmitted through contaminated food and water sources. Identification of Arcobacter by biochemical tests is difficult and isolation remains the gold standard method. Current diagnostic advances have provided various molecular methods for efficient detection and differentiation of the Arcobacters at genus and species level. To overcome the emerging antibiotic resistance problem there is an essential need to explore the potential of novel and alternative therapies. Strengthening of the diagnostic aspects is also suggested as in most cases Arcobacters goes unnoticed and hence the exact epidemiological status remains uncertain. This review updates the current knowledge and many aspects of this important food-borne pathogen, namely etiology, evolution and emergence, genetic diversity, epidemiology, the disease in animals and humans, public health concerns, and advances in its diagnosis, prevention and control.

Enhanced Single-tube Multiplex PCR Assay for Detection and Identification of Six Arcobacter Species

AIM

A single-tube multiplex PCR (mPCR) assay was developed for rapid, sensitive and simultaneous detection and identification of six Arcobacter species including two new species, A. lanthieri and A. faecis, along with A. butzleri, A. cibarius, A. cryaerophilus and A. skirrowii on the basis of differences in the lengths of their PCR products. Previously designed monoplex, mPCR and RFLP assays do not detect or differentiate A. faecis and A. lanthieri from other closely related known Arcobacter spp.

METHODS AND RESULTS

Primer pairs for each target species (except A. skirrowii) and mPCR protocol were newly designed and optimized using variable regions of housekeeping including cpn60, gyrA, gyrB and rpoB genes. The accuracy and specificity of the mPCR assay was assessed using DNA templates from six targets and 11 other Arcobacter spp. as well as 50 other bacterial reference species and strains. Tests on the DNA templates of target Arcobacter spp. were appropriately identified, whereas all 61 other DNA templates from other bacterial species and strains were not amplified. Sensitivity and specificity of the mPCR assay was 10 pg μl^-1 of DNA concentration per target species. The optimized assay was further evaluated, validated and compared with other mPCR assays by testing Arcobacter cultures isolated from various faecal and water sources.

CONCLUSIONS

Study results confirm that the newly developed mPCR assay is rapid, accurate, reliable, simple, and valuable for the simultaneous detection and routine diagnosis of six human- and animal-associated Arcobacter spp.

SIGNIFICANCE AND IMPACT OF THE STUDY

The new mPCR assay is useful not only for pure but also mixed cultures. Moreover, it has the ability to rapidly detect six species which enhances the value of this technology for aetiological and epidemiological studies.

Prevalence and diversity of waterborne Arcobacter butzleri in southwestern Alberta, Canada

Arcobacter butzleri is a potential enteric pathogen to human beings, but its reservoirs and modes of transmission are largely unverified. Microbiological and molecular detection and subtyping techniques can facilitate surveillance of A. butzleri in hosts and environmental reservoirs. We isolated A. butzleri from 173 surface water samples (25.6%) and 81 treated wastewater samples (77.9%) collected in southwestern Alberta over a 1-year period. Arcobacter butzleri isolates (n = 500) were genotyped and compared to determine diversity of A. butzleri in southwestern Alberta. Culture methods affected the frequency of detection and genotype diversity of A. butzleri, and isolation comprehensiveness was different for surface waters and treated wastewaters. Detection of A. butzleri in the Oldman River Watershed corresponded with season, river flow rates, and fecal coliform densities. Arcobacter butzleri was detected most frequently in treated wastewater, in the Oldman River downstream from treated wastewater outfalls, and in tributaries near areas of intensive confined feeding operations. All sample sources possessed high genotype diversity, and A. butzleri isolates from treated wastewaters were genetically similar to isolates from the Oldman River downriver from treated wastewater outfall sites. In southwestern Alberta, municipal and agricultural activities contribute to the density and genotype diversity of A. butzleri in surface waters.

Pathogens of Food Animals: Sources, Characteristics, Human Risk, and Methods of Detection

Pathogens associated with food production (livestock) animals come in many forms causing a multitude of disease for humans. For the purpose of this review, these infectious agents can be divided into three broad categories: those that are associated with bacterial disease, those that are associated with viruses, and those that are parasitic in nature. The goal of this chapter is to provide the reader with an overview of the most common pathogens that cause disease in humans through exposure via the food chain and the consequence of this exposure as well as risk and detection methods. We have also included a collection of unusual pathogens that although rare have still caused disease, and their recognition is warranted in light of emerging and reemerging diseases. These provide the reader an understanding of where the next big outbreak could occur. The influence of the global economy, the movement of people, and food makes understanding production animal-associated disease paramount to being able to address new diseases as they arise.

Genetic diversity of Arcobacter isolated from bivalves of Adriatic and their interactions with Mytilus galloprovincialis hemocytes

The human food-borne pathogens Arcobacter butzleri and A. cryaerophilus have been frequently isolated from the intestinal tracts and fecal samples of different farm animals and, after excretion, these microorganisms can contaminate the environment, including the aquatic one. In this regard, A. butzleri and A. cryaerophilus have been detected in seawater and bivalves of coastal areas which are affected by fecal contamination. The capability of bivalve hemocytes to interact with bacteria has been proposed as the main factor inversely conditioning their persistence in the bivalve. In this study, 12 strains of Arcobacter spp. were isolated between January and May 2013 from bivalves of Central Adriatic Sea of Italy in order to examine their genetic diversity as well as in vitro interactions with bivalve components of the immune response, such as hemocytes. Of these, seven isolates were A. butzleri and five A. cryaerophilus, and were genetically different. All strains showed ability to induce spreading and respiratory burst of Mytilus galloprovincialis hemocytes. Overall, our data demonstrate the high genetic diversity of these microorganisms circulating in the marine study area. Moreover, the Arcobacter-bivalve interaction suggests that they do not have a potential to persist in the tissues of M. galloprovincialis.

Efficacy of wastewater treatment on Arcobacter butzleri density and strain diversity

Arcobacter butzleri is a suspected waterborne enteric pathogen that is ubiquitous in the environment, but the degree to which wastewater treatment prevents entry of A. butzleri into environmental waters and the risks posed are not well established. Untreated and treated wastewater samples (n = 260) were collected weekly from the Lethbridge and Fort Macleod wastewater treatment facilities (the two major municipal inputs in southwestern Alberta, Canada) from May 2008 to April 2009. Untreated wastewaters contained high densities of A. butzleri and fecal coliform indicators, and densities at Lethbridge were typically higher than at Fort Macleod. Data indicated that A. butzleri and fecal coliform densities in wastewater were greatest in autumn and lowest in winter. Mechanical and biological treatment of wastewaters reduced but did not eliminate fecal coliform indicators or A. butzleri. At Lethbridge, UVB irradiation of mechanically and biologically treated wastewater further reduced densities of fecal coliform indicators. There was high A. butzleri genotype diversity in all sample sources, and survival during treatment was not strain-dependent. No genotype was dominant in any sample source, but 8.9% of genotypes were recurrent over time, and 4.4% of genotypes were detected at both wastewater treatment facilities. The current study demonstrates that viable A. butzleri are able to survive wastewater treatment, including UVB irradiation, which may lead to increased density and genetic diversity of this suspected pathogen in environmental waters via wastewater effluent discharge.

Evaluation of Various Campylobacter-Specific Quantitative PCR (qPCR) Assays for Detection and Enumeration of Campylobacteraceae in Irrigation Water and Wastewater via a Miniaturized Most-Probable-Number-qPCR Assay

Campylobacter spp. are the leading cause of bacterial gastroenteritis worldwide, and water is increasingly seen as a risk factor in transmission. Here we describe a most-probable-number (MPN)-quantitative PCR (qPCR) assay in which water samples are centrifuged and aliquoted into microtiter plates and the bacteria are enumerated by qPCR. We observed that commonly used Campylobacter molecular assays produced vastly different detection rates. In irrigation water samples, detection rates varied depending upon the PCR assay and culture method used, as follows: 0% by the de Boer Lv1-16S qPCR assay, 2.5% by the Van Dyke 16S and Jensen glyA qPCR assays, and 75% by the Linton 16S endpoint PCR when cultured at 37°C. Primer/probe specificity was the major confounder, with Arcobacter spp. routinely yielding false-positive results. The primers and PCR conditions described by Van Dyke et al. (M. I. Van Dyke, V. K. Morton, N. L. McLellan, and P. M. Huck, J Appl Microbiol 109:1053-1066, 2010, http://dx.doi.org/10.1111/j.1365-2672.2010.04730.x) proved to be the most sensitive and specific for Campylobacter detection in water. Campylobacter occurrence in irrigation water was found to be very low (<2 MPN/300 ml) when this Campylobacter-specific qPCR was used, with the most commonly detected species being C. jejuni, C. coli, and C. lari Campylobacters in raw sewage were present at ∼10(2)/100 ml, with incubation at 42°C required for reducing microbial growth competition from arcobacters. Overall, when Campylobacter prevalence and/or concentration in water is reported using molecular methods, considerable validation is recommended when adapting methods largely developed for clinical applications. Furthermore, combining MPN methods with molecular biology-based detection algorithms allows for the detection and quantification of Campylobacter spp. in environmental samples and is potentially suited to quantitative microbial risk assessment for improved public health disease prevention related to food and water exposures.

IMPORTANCE

The results of this study demonstrate the importance of assay validation upon data interpretation of environmental monitoring for Campylobacter when using molecular biology-based assays. Previous studies describing Campylobacter prevalence in Canada utilized primers that we have determined to be nonspecific due to their cross-amplification of Arcobacter spp. As such, Campylobacter prevalence may have been vastly overestimated in other studies. Additionally, the development of a quantitative assay described in this study will allow accurate determination of Campylobacter concentrations in environmental water samples, allowing more informed decisions to be made about water usage based on quantitative microbial risk assessment.

Occurrence of emerging food-borne pathogenic Arcobacter spp. isolated from pre-cut (ready-to-eat) vegetables

Given that changes in consumer food behaviours have led to an increase in the demand for pre-cut ready-to-eat (RTE) vegetables, and that few data are currently available on the occurrence of Arcobacter spp. in such foods, the aim of the present study was to assess the occurrence of Arcobacter spp. that carry virulence-associated genes on pre-cut RTE vegetables, using cultural and molecular methods. Arcobacter was detected using biomolecular identification methods in 44/160 (27.5%) of the samples, of which 40/44 (90.9%) isolates corresponded to A. butzleri and 4/44 (9.1%) to A. cryaerophilus. Studying the incidence of 9 virulence-associated genes revealed the widespread distribution of these genes among the Arcobacter isolates tested. The results obtained in our research provided plenty of information on the health risks associated with the direct consumption of raw vegetables, and highlight the need to implement further studies at each level of the production chain, in order to obtain further information to help protect human health.

Comparative Detection and Quantification of Arcobacter butzleri in Stools from Diarrheic and Nondiarrheic People in Southwestern Alberta, Canada

Arcobacter butzleri has been linked to enteric disease in humans, but its pathogenicity and epidemiology remain poorly understood. The lack of suitable detection methods is a major limitation. Using comparative genome analysis, we developed PCR primers for direct detection and quantification ofA. butzleri DNA in microbiologically complex matrices. These primers, along with existing molecular and culture-based methods, were used to detectA. butzleri and enteric pathogens in stools of diarrheic and nondiarrheic people (n= 1,596) living in southwestern Alberta, Canada, from May to November 2008. In addition, quantitative PCR was used to compare A. butzleridensities in diarrheic and nondiarrheic stools.Arcobacter butzleriwas detected more often by PCR (59.6%) than by isolation methods (0.8%). Comparison by PCR-based detection found no difference in the prevalence ofA. butzleri between diarrheic (56.7%) and nondiarrheic (45.5%) individuals. Rates of detection in diarrheic stools peaked in June (71.1%) and October (68.7%), but there was no statistically significant correlation between the presence ofA. butzleri and patient age, sex, or place of habitation. Densities ofA. butzleriDNA in diarrheic stools (1.6 ± 0.59 log10 copies mg(-1)) were higher (P= 0.007) than in nondiarrheic stools (1.3 ± 0.63 log10copies mg(-1)). Of the 892 diarrheic samples that were positive for A. butzleri, 74.1% were not positive for other bacterial and/or viral pathogens. The current study supports previous work suggesting that A. butzleri pathogenicity is strain specific and/or dependent on other factors, such as the level of host resistance.

Occurrence and antimicrobial resistance of emergent Arcobacter spp. isolated from cattle and sheep in Iran

This study is conducted to determine the occurrence and antimicrobial resistance of Arcobacter spp. isolated from clinically healthy food animals. A total of 308 samples from cattle (200) and sheep (108) were collected from Shiraz slaughterhouse, southern Iran to investigate the presence of the important Arcobacter spp. using cultivation and Polymerase Chain Reaction (PCR) methods. Antimicrobial susceptibility of Arcobacter isolates was determined for 18 antibiotics using disk diffusion method. Among 308 samples, 27 (8.7%) and 44 (14.28%) were positive for the presence of Arcobacter species with cultivation and PCR procedures, respectively. The predominant species was A. butzleri in both cattle (58.33%) and sheep (55%). In addition, concurrent incidence of the species was observed in 25% of the positive samples. All Arcobacter isolates were resistant to rifampicin, vancomycin, ceftriaxone, trimethoprim and cephalothin. The isolates showed high susceptibility to tetracycline, oxytetracycline, erythromycin, ciprofloxacin, kanamycin, amikacin, gentamicin and enrofloxacin. No significant difference among cattle and sheep isolates in resistance pattern was observed. The results indicate that cattle and sheep are significant intestinal carriers for Arcobacter spp. Moreover, tetracycline and aminoglycosides showed great effects on Arcobacter species in antibiogram test and can be used for treatment of human Arcobacter infections.

Diversity and composition of the bacterial community in Amphioxus feces

Amphioxus is a typical filter feeder animal and is confronted with a complex bacterial community in the seawater of its habitat. It has evolved a strong innate immune system to cope with the external bacterial stimulation, however, the ecological system of the bacterial community in Amphioxus remains unknown. Through massive parallel 16S rRNA gene tag pyrosequencing, the investigation indicated that the composition of wild and lab-cultured Amphioxus fecal bacteria was complex with more than 85,000 sequence tags being assigned to 12/13 phyla. The bacterial diversity between the two fecal samples was similar according to OTU richness of V4 tag, Chao1 index, Shannon index and Rarefaction curves, however, the most prominent bacteria in wild feces were genera Pseudoalteromonas (gamma Proteobacteria) and Arcobacter (epsilon Proteobacteria); the highly abundant bacteria in lab-cultured feces were other groups, including Leisingera, Phaeobacter (alpha Proteobacteria), and Vibrio (gamma Proteobacteria). Such difference indicates the complex fecal bacteria with the potential for multi-stability. The bacteria of habitat with 28 assigned phyla had the higher bacterial diversity and species richness than both fecal bacteria. Shared bacteria between wild feces and its habitat reached to approximately 90% (153/169 genera) and 28% (153/548 genera), respectively. As speculative, the less diversity of both fecal bacteria compared to its habitat partly because Amphioxus lives buried and the feces will ultimately end up in the sediment. Therefore, our study comprehensively investigates the complex bacterial community of Amphioxus and provides evidence for understanding the relationship of this basal chordate with the environment.

Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii Circulation in a Dairy Farm and Sources of Milk Contamination

Even though dairy cows are known carriers of Arcobacter species and raw or minimally processed foods are recognized as the main sources of human Arcobacter infections in industrialized countries, data on Arcobacter excretion patterns in cows and in milk are scant. This study aimed to identify potentially pathogenic Arcobacter species in a dairy herd and to investigate the routes of Arcobacter transmission among animals and the potential sources of cattle infection and milk contamination. A strategy of sampling the same 50 dairy animals, feed, water, and milk every month for a 10-month period, as well as the sampling of quarter milk, animal teats, the milking environment, and animals living on the farm (pigeons and cats), was used to evaluate, by pulsed-field gel electrophoresis (PFGE), the characteristic patterns in animals, their living environment, and the raw milk they produced. Of the 463 samples collected, 105 (22.6%) were positive for Arcobacter spp. by culture examination. All the matrices except quarter milk and pigeon gut samples were positive, with prevalences ranging from 15 to 83% depending on the sample. Only three Arcobacter species, Arcobacter cryaerophilus (54.2%), A. butzleri (34.2%), and A. skirrowii (32.3%), were detected. PFGE analysis of 370 isolates from positive samples provided strong evidence of Arcobacter circulation in the herd: cattle likely acquire the microorganisms by orofecal transmission, either by direct contact or from the environment, or both. Water appears to be a major source of animal infection. Raw milk produced by the farm and collected from a bulk tank was frequently contaminated (80%) by A. butzleri; our PFGE findings excluded primary contamination of milk, whereas teats and milking machine surfaces could be sources of Arcobacter milk contamination.

Zoonotic species of the genus Arcobacter in poultry from different regions of Costa Rica

In recent years, emerging pathogens have received special attention due to their consequences for public health. Given that Arcobacter has been isolated in Costa Rica from commercial meat poultry samples, the aim of this research was to determine its isolation frequency from laying hens, broilers, ducks, and geese and to compare two types of samples, namely, cloacal swabs and stool collection. Arcobacter was isolated from 22 (11%) of the 200 samples examined. Fifteen (55%), eight (30%), and four (15%) of the isolated strains were identified as A. butzleri, A. cryareophilus, and Arcobacter spp., respectively. Also, there is a statistically significant difference among the isolation frequencies of Arcobacter for the types of samples evaluated, yielding more isolates from stool samples than from cloacal swab collection. This work describes the distribution of Arcobacter in farm animals as potential sources for its spread from animal-derived products.

Presence and analysis of plasmids in human and animal associated arcobacter species

In this study, we report the screening of four Arcobacter species for the presence of small and large plasmids. Plasmids were present in 9.9% of the 273 examined strains. One Arcobacter cryaerophilus and four Arcobacter butzleri plasmids were selected for further sequencing. The size of three small plasmids isolated from A. butzleri and the one from A. cryaerophilus strains ranged between 4.8 and 5.1 kb, and the size of the large plasmid, isolated from A. butzleri, was 27.4 kbp. The G+C content of all plasmids ranged between 25.4% and 26.2%. A total of 95% of the large plasmid sequence represents coding information, which contrasts to the 20 to 30% for the small plasmids. Some of the open reading frames showed a high homology to putative conserved domains found in other related organisms, such as replication, mobilization and genes involved in type IV secretion system. The large plasmid carried 35 coding sequences, including seven genes in a contiguous region of 11.6 kbp that encodes an orthologous type IV secretion system found in the Wolinella succinogenes genome, Helicobacter pylori and Campylobacter jejuni plasmids, which makes this plasmid interesting for further exploration.

Food Safety: Emerging Pathogens

This article presents information related to emerging pathogens that are foodborne or have the potential to be foodborne including bacteria, viruses, and parasites. The phenotypic characteristics of these pathogens, their epidemiology, prevalence in foods, and transmission routes to humans as well as means for their control are also discussed.

Abortions in sheep associated with Arcobacter skirrowii infection

The history, circumstances, clinical signs, post mortem lesions, morbidity, mortality and laboratory findings are described in an abortion storm in sheep that occurred in Mpumalanga, South Africa, associated with infection with Arcobacter skirrowii. Altogether, about 200 Suffolk Down ewes lost 60 lambs in late pregnancy or at term. Although only three foetuses were submitted for investigation, two had signs consistent with a diagnosis of A. skirrowii infection and the organism was isolated from the placentas of both specimens. No abortions had occurred in previous years, or have subsequently. There were no animal introductions prior to the outbreak that could have indicated a source of infection. One stillborn lamb submitted subsequently had lesions consistent with dystocia, and the history and circumstantial evidence indicated that dystocia had been a factor in several more losses. No ewes or rams had shown signs of diarrhoea or other diseases associated with A. skirrowii infection. Twenty-two faecal, preputial and vaginal swab specimens taken from six rams and 13 ewes after the abortion event were all negative for A. skirrowii. This is the first report of abortions in sheep associated with A. skirrowiiin South Africa. Because the genus Arcobacter is similar to Campylobacter, it is possible that infection has gone unrecognised in the past. Veterinarians and laboratories should take note and include this genus in the list of potential abortifacient organisms. The possible role of Arcobacter species in other diseases like enteritis and mastitis, as well as the potential role as a zoonosis, must be borne in mind.

Bioaccumulation experiments in mussels contaminated with the food-borne pathogen Arcobacter butzleri: preliminary data for risk assessment

The aim of this study was to evaluate, at a laboratory scale, the ability of this microorganism to grow in seawater and bioaccumulate in mussels (Mytilus galloprovincialis) maintained in constantly aerated tanks, containing twenty litres of artificial seawater. Three concentrations of A. butzleri LMG 10828^T were tested (about 5 × 10⁶ CFU/mL, 5 × 10⁴ CFU/mL, and 5 × 10² CFU/mL). Following contamination, enumeration of A. butzleri was performed from water and mussels each day, for up to 96 h. Three contamination experiments with artificial seawater in absence of mussels were also performed in the same manner. In the experiments with mussels, A. butzleri declined in water of approximately 1 log every 24 h from the contamination. In artificial seawater without mussels the concentration of A. butzleri remained on the same logarithmic level in the first 48 h and then decreased of about 1 log every 24 hours. In mussels, the concentration was approximately 2 log lower than the exposition level after 24 h from the contamination, and then it decreased exponentially of 1 log every 24 h. Our findings suggest that in the experimental conditions tested A. butzleri is neither able to effectively grow in seawater nor bioaccumulate in mussels, at least in the free and cultivable form.

Multilocus sequence typing and biocide tolerance of Arcobacter butzleri from Danish broiler carcasses

Background

Arcobacter spp. have in recent years received increasing interest as potential emerging enteropathogens and zoonotic agents. They are associated with various animals including poultry and can be isolated from meat products. The possibilities of persistence and cross-contamination in slaughterhouses during meat processing are not well established. We have evaluated the occurrence and persistence of Arcobacter spp. in a Danish slaughterhouse and determined the sensitivity of isolates to sodium hypochlorite, a commonly used biocide.

Results

Arcobacter contamination was examined in a broiler slaughterhouse by selective enrichment of 235 swabs from the processing line during two production days and after sanitizing in between. In total 13.6% of samples were positive for A. butzleri with the majority (29 of 32 isolates) originating from the evisceration machine. No Arcobacter spp. was isolated after cleaning. A. butzleri isolates confirmed by PCR were typed by multilocus sequence typing (MLST) resulting in 10 new sequence types (STs). Two sequence types were isolated on both processing days. Minimum inhibitory concentration (MIC) to sodium hypochlorite was determined to 0.5% hypochlorite biocide (500 ppm chlorine) for most isolates, which allows growth of A. butzleri within the working concentration of the biocide (0.2 - 0.5%).

Conclusions

A. butzleri was readily isolated from a Danish broiler slaughterhouse, primarily in the evisceration machine. Typing by MLST showed high strain variability but the recurrence of two STs indicate that some persistence or cross-contamination takes place. Importantly, the isolates tolerated sodium hypochlorite, a biocide commonly employed in slaughterhouse sanitizing, at levels close to the disinfection concentration, and thus, A. butzleri may survive the disinfection process although this was not observed in our study.

Temporal and farm-management-associated variation in faecal pat prevalence ofArcobacterspp. in ruminants

In a 2-year longitudinal study of adult animals on 15 dairy farms and four sheep farms in Lancashire, UK,Arcobacterspp. were isolated from all farms although not at every sampling occasion. Faecal samples were collected and cultured using standard techniques for isolation of campylobacters. Assignment to species was via PCR assays. Apparent prevalence ofArcobacterspp. was higher in dairy cattle compared to sheep (40·1%vs.8%,P < 0·001) and in housed cattle compared to cattle at pasture (50·1%vs.20·9%,P < 0·001). This was reflected in the higher prevalence observed in herds that were housed (n = 4) all year compared to herds that grazed cattle on pasture in the summer and housed cattle in the winter (n = 11) (55·5%vs. 36%,P < 0·001). In the case of sheep, peak prevalence was observed in autumn with increased prevalence also being associated with improving pasture quality. There was an apparent inverse association between the faecal pat prevalence ofArcobacterspp. andCampylobacter jejunialthough this may in part be an artefact of laboratory test method sensitivity, whereby a relative increase in the frequency of one bacterial species would reduce the sensitivity of detecting the other.

Exploring the diversity of Arcobacter butzleri from cattle in the UK using MLST and whole genome sequencing

Arcobacter butzleri is considered to be an emerging human foodborne pathogen. The completion of an A. butzleri genome sequence along with microarray analysis of 13 isolates in 2007 revealed a surprising amount of diversity amongst A. butzleri isolates from humans, animals and food. In order to further investigate Arcobacter diversity, 792 faecal samples were collected from cattle on beef and dairy farms in the North West of England. Arcobacter was isolated from 42.5% of the samples and the diversity of the isolates was investigated using multilocus sequence typing. An A. butzleri whole genome sequence, obtained by 454 shotgun sequencing of an isolate from a clinically-healthy dairy cow, showed a number of differences when compared to the genome of a human-derived A. butzleri isolate. PCR-based prevalence assays for variable genes suggested some tentative evidence for source-related distributions. We also found evidence for phenotypic differences relating to growth capabilities between our representative human and cattle isolates. Our genotypic and phenotypic observations suggest that some level of niche adaptation may have occurred in A. butzleri.

Prevalence and concentration of Arcobacter spp. on Australian Beef Carcasses

The International Commission on Microbiological Specifications for Foods (ICMSF) classified Arcobacter spp. as emerging pathogens in 2002. Arcobacter spp. have been isolated from numerous food products at retail and from animal carcasses and feces at slaughter. A survey was conducted to determine both the prevalence and concentration of Arcobacter spp. on pre-chill beef carcasses. Surface swab samples were collected from 130 beef carcasses at the end of processing, prior to chilling. The concentration of Arcobacter spp. was determined by a most-probable-number per square centimeter (3 by 3) method with a limit of detection of 0.12 CFU/cm(2). Of the 100 carcasses examined from export abattoirs, 20 (20.0%) were contaminated with Arcobacter spp., and 5 of these had quantifiable levels of contamination ranging from 0.12 to 0.31 CFU/cm(2). Of the 30 carcasses examined at a pet food abattoir, 25 (83.3%) were contaminated with Arcobacter spp., and 10 of these had quantifiable levels of contamination ranging from 0.12 to 0.95 CFU/cm(2). Three species of Arcobacter, A. butzleri, A. cryaerophilus, and A. skirowii, were identified by PCR. Each of the species was present in an approximately equal ratio from export abattoirs. This study demonstrates that slaughter practices at export abattoirs are sufficient to maintain both low prevalence and low levels of contamination of beef carcasses with Arcobacter spp.

Prevalence, distribution and antibiotic resistance of emergent Arcobacter spp. from clinically healthy cattle and goats

Prevalence, distribution and antibiotic resistance of Arcobacter spp. were investigated in cattle, goats, floor and treated water samples in this study. The prevalence of Arcobacter in adult and young was recorded as 8/110 (7.27%) and 4/83 (4.81%), respectively, which showed insignificant difference (P = 0.3503) in detection rates between adult and young cattle. A total of 33.33% of the floor samples and 11.11% of the treated water samples analysed were determined as positive for Arcobacter. Among the species isolated, over all, A. butzleri (45%) was the most frequently detected species, followed by A. skirrowii (5%). A. butzleri was isolated from adult cattle, floor and water samples at the rates of 75.0%, 33.4% and 50%, respectively. Co-colonization of species was not uncommon, and 50% of the samples were carrying more than one Arcobacter species. Only 12.5% sample from cattle (adult) was detected positive for only A. skirrowii. All samples from young animals, floor and water contained mixed isolates. None of the samples from goat farm was found to be carrying Arcobacter species. On profiling of antimicrobial resistance patterns, it was found that only one A. butzleri isolate (3.7%) was sensitive to all nine antibiotics tested. A. butzleri was found highly resistant to ampicillin (55.6%), followed by cefotaxime (33.4%) and ciprofloxacin (33.4%). Overall, 20% of the isolates showed multidrug resistance (resistant ≥4 antibiotics). Gentamicin and enrofloxacin can be used as drugs of choice for the treatment for Arcobacter infections.

Occurrence of putative virulence genes in arcobacter species isolated from humans and animals

Interest in arcobacters in veterinary and human public health has increased since the first report of the isolation of arcobacters from food of animal origin. Since then, studies worldwide have reported the occurrence of arcobacters on food and in food production animals and have highlighted possible transmission, especially of Arcobacter butzleri, to the human population. In humans, arcobacters are associated with enteritis and septicemia. To assess their clinical relevance for humans and animals, evaluation of potential virulence factors is required. However, up to now, little has been known about the mechanisms of pathogenicity. Because of their close phylogenetic affiliation to the food-borne pathogen Campylobacter and their similar clinical manifestations, the presence of nine putative Campylobacter virulence genes (cadF, ciaB, cj1349, hecA, hecB, irgA, mviN, pldA, and tlyA) previously identified in the recent Arcobacter butzleri ATCC 49616 genome sequence was determined in a large set of human and animal Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii strains after the development of rapid and accurate PCR assays and confirmed by sequencing and dot blot hybridization.