Arcobacter Isolates Research Articles

A meta-analytic perspective on Arcobacter spp. antibiotic resistance.

Over the years, an increased prevalence of resistant strains of Arcobacter has been observed, which may be due to Arcobacter exposure to antibiotics used both in animal production and human medicine. A systematic review was performed with the objective of summarising the results of the rates of antimicrobial resistance of Arcobacter isolates. The systematic review was performed according to PRISMA (Preferred Reported Items for Systematic Reviews and Meta-Analysis) recommendations, followed by meta-analysis. It was observed that the resistance rate ranged between 69.3-99.2% for penicillins and 30.5-97.4% for cephalosporins. The overall percentage of resistance to fluoroquinolones ranged from 4.3% to 14.0%, with the highest resistance percentage observed for levofloxacin. Resistance rates ranged between 10.7-39.8% for macrolides, 1.8-12.9% for aminoglycosides and 0.8-7.1% for tetracyclines. These results show that Arcobacter spp. present resistance to various antibiotics commonly used and advocate further studies of the associated resistance mechanisms.

Isolation of Arcobacter spp. from domestic ducks and geese and identification of the recovered isolates by using molecular method

This study aimed to investigate the role of healthy domestic geese and ducks as Arcobacter carriers. A total of 599 samples, including 330 cloacal swab and 116 fecal samples from geese, and 153 cloacal swab samples from ducks raised on family farms were analysed. For this purpose, the membrane filtration method was applied. In this study, Arcobacter spp. were isolated at rates of 16.7% and 12.93% from cloacal swab and stool samples of geese, respectively, and 26.14% from cloacal swab samples of ducks. Obtained isolates were identified by multiplex PCR (m-PCR) as A. cryaerophilus, A. butzleri, and A. skirrowii. Seasonal analyses of Arcobacter spp. that were isolated from the examined samples were done for the months in which the samples were collected. While the highest rate of Arcobacter spp. in cloacal swab samples in geese was obtained in October, Arcobacter spp. was found in stool samples in July. The highest isolation rate for ducks was obtained in July as well. These isolation rates suggest that the stool may play an important role in the transmission and spread of arcobacters. Consequently, ducks and geese, which are reservoirs for arcobacters because they carry Arcobacter spp. in their digestive systems, play a considerable role in the transmission of arcobacters to other animals and to humans, thereby being vectors of infection.

Prevalence of pathogenic Arcobacter species in South Korea: Comparison of two protocols for isolating the bacteria from foods and examination of nine putative virulence genes

Contamination of foodstuffs by potentially enteropathogenic Arcobacter spp. is becoming a concern worldwide. However, few studies have examined virulence-associated genes in isolates of Arcobacter spp. from food. Here, we investigated the prevalence of three pathogenic Arcobacter species, A. butzleri, A. cryaerophilus, and A. skirrowii, in chicken, pork, and leafy green vegetables (n = 323) in South Korea. Samples were examined using two different protocols selected from a literature review: Acrobacter selective broth (ASB) II + Arcobacter selective medium (ASM) II (protocol A), and ASB II + modified charcoal cefoperazone deoxycholate agar supplemented with CAT (protocol B). Overall, Arcobacter spp. were detected in 45.8% of food samples, and the recovery rate of protocol B (37.8%) was significantly higher than that of protocol A (30.7%) (p < 0.05). Refrigerated chicken gizzard samples showed the highest detection rate (100%), followed by refrigerated chicken wing (79.5%), intestine (77.3%), neck skin (63.3%), pork (55.6%), frozen chicken legs (5.0%), and leafy green vegetables (4.4%) (p < 0.05). All isolates from chicken and leafy green vegetables were identified as A. butzleri, whereas A. cryaerophilus and A. skirrowii were mainly detected in pork. Most samples (95.8%) harbored more than one of nine putative virulence factors (cadF, ciaB, cj1349, hecA, hecB, mviN, pldA, irgA, and tlyA), and 91.3% harbored more than two. Isolates harboring all nine putative virulence genes were obtained from 1.9% of samples: five pork and one chicken. This study provides comprehensive and de facto evidence regarding prevalence of an emerging pathogen, Arcobacter spp., in various foods, along with their virulence potential. The results justify further research with respect to their role in food safety.

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.

Occurrence of virulence-associated genes in Arcobacter butzleri and Arcobacter cryaerophilus isolates from foodstuff, water, and clinical samples within the Czech Republic.

Bacteria of the Arcobacter (A.) genus, originating mainly from food and water, are dreaded germs for humans as well as animals. However, the virulence of these bacteria has not been fully elucidated yet. This study looked at the occurrence of eight virulence-associated factors (ciaB, cj1349, pldA, irgA, hecA, tlyA, mviN, hecB) in a total of 80 isolates of Arcobacter butzleri and 22 isolates of A. cryaerophilus. The isolates were derived from food, water, and clinical samples. A polymerase chain reaction using specific primers was used to detect these virulence-associated genes. The presence of all genes in the isolates of A. butzleri (98.8% ciaB, 95.0% cj1349, 98.8% pldA, 22.5% irgA, 31.3% hecA, 95.0% tlyA, 97.5% mviN, 38.8% hecB) and A. cryaerophilus (95.5% ciaB, 0.0% cj1349, 9.1% pldA, 0.0% irgA, 0.0% hecA, 31.8% tlyA, 90.9% mviN, 0.0% hecB) was monitored. Among the tested isolates, there were 13 isolates (12.7%) of A. butzleri, in which the presence of all eight virulence-associated genes was recorded in the genome. In contrast, in one A. cryaerophilus strain, none of the observed genes were detected. The presence of ciaB and mviN genes was significantly more frequent in A. cryaerophilus isolates than other genes (P < 0.05). In general, more virulence-associated genes have been detected in A. butzleri isolates compared to A. cryaerophilus. The most common gene combination (ciaB, cj1349, pldA, tlyA, mviN) was detected in case of 39 isolates. In 50.0% of A. butzleri isolates derived from clinical samples, all eight virulence-associated genes were significantly more frequently detected (P < 0.05). The tlyA gene occurred significantly more frequent in A. butzleri isolates from meat and water samples and irgA and hecB genes in clinical samples. Therefore, our study provides information about occurrence of virulence-associated genes in genome of Arcobacter isolates. These findings could be hazardous to human health, because the presence of virulence-associated genes is the assumption for potential dangerousness of these bacteria. Our results indicate high incidence of virulence-associated genes in Arcobacter genomes and hence potentially pathogenic properties of the studied strains.

Occurrence of Arcobacter species in animal faeces, foods of animal origin and humans in Andhra Pradesh, India

A total of n=510 samples comprising of faecal swabs from livestock (n=245), foods of animal origin (n=180) and human stools (n=85) were examined to detect Arcobacter species employing cultural and PCR methods. Overall, 11.7% of samples were found positive for Arcobacter species by genus-specific PCR. On screening faecal samples of livestocks, higher positivity was observed in pigs (23.3%), followed by chicken (16.6%), turkey (15.0%), cattle (10.0%), duck (10.0%) and sheep (6.6%). With regard to foods of animal origin, higher positivity was observed in pork samples (15.0%), followed by chicken (12.5%), milk (10.0%) and mutton (7.5%). In humans, the stool samples of farm workers revealed high positivity (13.3%) followed by veterinary students (8.0%) and diarrhoeic humans (6.66%). Using cultural method, a total of 41 (8.03%) Arcobacter isolates were recovered. The multiplex-PCR assay enabled detection of Arcobacter butzleri (16/41), Arcobacter cryaerophilus (13/41) and Arcobacter skirrowii (12/41). The results signify the occurrence of Arcobacter species in animal faeces, foods of animal origin and humans in Andhra Pradesh, India.

Isolation and determination of antimicrobial resistance of Arcobacter species isolated from animal faeces in the Diyarbakir region of Turkey using the 16S rDNA-RFLP method

In this study, the presence of Arcobacter spp. was investigated in the faeces of cattle, sheep, goats, dogs and cloacal swab samples of chickens using the 16S rDNA-RFLP method. The prevalence of Arcobacter in these species was found to be 13%, 12%, 16%, 4% and 33%, respectively. On the other hand, Arcobacter spp. could not be isolated from rabbit faeces. A total of 78 (13%) Arcobacter spp. isolates were obtained from the 500 faecal samples and 100 cloacal swab samples examined in this study. From these 78 Arcobacter isolates, 24 (30.8%), 20 (25.6%), 11 (14.1%), 8 (10.7%), 4 (5.1%), 3 (3.9%) and 2 (2.6%) were identified by 16S rDNA-RLFP as A. cryaerophilus, A. butz- leri, A. skirrowii, A. cloacae, A. cibarius, A. halophilus, and A. nitrofigilis, respectively. All A. cryaerophilus (n = 24) isolates were found to be resistant to cloxacillin; all A. butzleri (n = 20) and A. skirrowii isolates were found to be resistant to penicillin/novobiocin, cefoperazone, tetracycline and cloxacillin. It was determined in this study that clinically healthy cattle, sheep, goats, dogs and chickens are reservoirs of Arcobacter spp.

Virulence gene profiles of Arcobacter species isolated from animals, foods of animal origin, and humans in Andhra Pradesh, India.

Aim::This study aimed to detect putative virulence genes in Arcobacter species of animal and human origin.Materials and Methods::A total of 41 Arcobacter isolates (16 Arcobacter butzleri, 13 Arcobacter cryaerophilus, and 12 Arcobacter skirrowii) isolated from diverse sources such as fecal swabs of livestock (21), raw foods of animal origin (13), and human stool samples (7) were subjected to a set of six uniplex polymerase chain reaction assays targeting Arcobacter putative virulence genes (ciaB, pldA, tlyA, mviN, cadF, and cj1349).Results::All the six virulence genes were detected among all the 16 A. butzleri isolates. Among the 13 A. cryaerophilus isolates, cadF, ciaB, cj1349, mviN, pldA, and tlyA genes were detected in 61.5, 84.6, 76.9, 76.9, 61.5, and 61.5% of isolates, respectively. Among the 12 A. skirrowii isolates, cadF, ciaB, cj1349, mviN, pldA, and tlyA genes were detected in 50.0, 91.6, 83.3, 66.6, 50, and 50% of isolates, respectively.Conclusion::Putative virulence genes were detected in majority of the Arcobacter isolates examined. The results signify the potential of Arcobacter species as an emerging foodborne pathogen.

Comparative isolation and genetic diversity of Arcobacter sp. from fish and the coastal environment.

Arcobacter sp. are emerging food- and water-borne human pathogens. In this study, comparison of two selective media suggested Arcobacter blood agar to be more efficient in yielding Arcobacter sp. from seafood. Furthermore, the isolation of Arcobacter sp. such as Arcobacter butzleri, A. skirrowii, A. mytili and A. defluvii from seafood suggests diverse sources of contamination of seafood by Arcobacter sp. Analysis of enterobacterial repetitive intergenic consensus sequence-PCR patterns of A. butzleri showed high genetic diversity and lack of clonality among the isolates. Arcobacter contamination of seafood is an emerging issue both from seafood safety and seafood trade point of view.

Occurence and antimicrobial resistance of Arcobacter species in food and slaughterhouse samples

The objectives of this study were i) to isolate Arcobacter species (Arcobacter butzleri, Arcobacter skirrowii, Arcobacter cryaerophilus) from different foods and sources, ii) to verify the isolates by multiplex PCR assay, iii) to detect the antibiotic resistance profiles of the isolates. In this study a total of 60 Arcobacter isolates were obtained. Arcobacter species were mostly isolated from swab samples (40%), followed by wastewater (29.1%), broiler wing meat (30%), raw milk (23.9%) and minced meat (6.6%). Regarding the seasonal distribution of Arcobacter from swab and wastewater samples, the bacterium was commonly isolated from wastewater in winter and spring, while it was frequently detected in swab samples during autumn and spring. All of the isolates were found to be resistant to nalidixic acid, ampicillin, rifampin, and erythromycin. The most effective antibiotic was tetracycline, because 96.66% of the isolates were susceptible against it. This is the first report of the isolation, seasonal distribution and antimicrobial susceptibility of Arcobacter species in cattle slaughterhouse samples in Turkey. These results indicate that foods of animal origin and cattle slaughterhouses are significant source of the antimicrobial resistant arcobacters.

Arcobacter Isolation from Minced Beef Samples in Costa Rica

The presence of Arcobacter spp. in minced meat (including beef) samples has been well documented in different countries, with varying frequencies. Nevertheless, the only Latin American country reporting this bacterium in minced beef samples is Mexico, with a 28.8% frequency in 2003. Previous studies in Costa Rica have demonstrated the presence of Arcobacter species in samples taken from the poultry production chain, but still there are no studies performed in bovine meat. The aim of this study was to determine the frequency of this bacterium in 120 samples of minced beef acquired from the Central Valley region of Costa Rica and to describe the antibiotic sensitivity pattern of the isolates obtained. A total of 75 different Arcobacter strains were isolated from minced beef samples, for a final frequency of 48.3%. After species PCR identification, the strains were classified as A. butzleri (37.3%), A. cibarius (14.7%), A. thereius (12%), and Arcobacter spp. (36%). All samples were sensitive to gentamicin but were resistant to ampicillin, levofloxacin, nalidixic acid, and ciprofloxacin. The results obtained in this study show that the frequency of isolation of Arcobacter in minced beef samples is high and that there is a high resistance rate for antibiotics in common use. This suggests that Arcobacter represents a health risk for Costa Rica and that control measures should be developed to decrease its potential impact.

Isolation and Identification of Arcobacter Species from Costa Rican Poultry Production and Retail Sources

Arcobacter is a gram-negative rod recognized as a potential food- and waterborne pathogen; nevertheless, little is known about the effects of this pathogen on human and animal health. Although Arcobacter species are commonly found in nature, poultry is suspected to be the main vehicle for the transmission of this pathogen. The aims of this work were to determine the prevalence of Arcobacter spp. in broilers produced in Costa Rica for human consumption and to analyze the pathogenic capacity of the isolates through the detection of virulence genes. One hundred fifty-two samples of cecal content (87 farms), 104 samples of carcass rinse after chiller (six processing plants), and 96 carcass rinses from as many retail stores were analyzed. The suspicious isolates were identified using genus-specific PCR, and species-level identification was achieved with a multiplex PCR. Virulence genes were identified using the protocol described by L. Douidah, L. de Zutter, J. Baré, P. De Vos, P. Vandamme, O. Vandenberg, A.-M. Van den Abeele, and K. Houf (J. Clin. Microbiol. 50:735-741, 2012), which includes nine different virulence genes. The overall isolation frequency of Arcobacter was 6.5% (n = 23). Eight (34.8%) of the isolates came from cecal content, 2 (8.7%) were isolated from samples taken after chiller, and 13 (56.5%) were from retail stores. The species isolated included A. thereius (30.4%), A. butzleri (21.7%), A. skirrowii (4.3%), and A. cibarius (4.3%). The remaining samples were classified as Arcobacter sp. Gene tlyA was the most prevalent virulence gene, present in 9 of 23 samples analyzed; genes hecA and pldA were present in one only strain each. A strain of A. butzleri isolated from a retail store presented the highest number of virulence genes (five), and 11 samples did not present any of the genes analyzed. The results obtained suggest that the presence of virulent Arcobacter isolates in the poultry production chain from Costa Rica could be a risk for individuals who consume the contaminated product.

Genetic Diversity of Arcobacter Species of Animal and Human Origin in Andhra Pradesh, India.

Arcobacter is an emerging foodborne pathogen having zoonotic significance. Enterobacterial repetitive intergenic consensus (ERIC) PCR and repetitive sequence-based PCR (rep-PCR) analysis of a total of 41 Arcobacter isolates revealed a greater degree of genetic diversity. ERIC-PCR genotyping distinguished 14, 13 and 12 genotypes among 16, 13 and 12 isolates of A. butzleri, A. cryaerophilus and A. skirrowii, respectively. Rep-PCR genotyping distinguished 15, 12 and 11 genotypes among 16, 13 and 12 isolates of A. butzleri, A. cryaerophilus and A. skirrowii, respectively. The discriminatory power for ERIC and rep-PCR was found to be 0.997 and 0.996, respectively. Close clustering between isolates of animal and human origin are indicative of probable zoonotic significance.

Susceptibility to 18 drugs and multidrug resistance of Arcobacter isolates from different sources within the Czech Republic.

Arcobacter spp. are considered to be potential foodborne pathogens, and consumption of contaminated food containing these bacteria could endanger human and animal health. Arcobacter butzleri and Arcobacter cryaerophilus are the species most frequently isolated from food of animal origin and from other samples. The aim of this study was to evaluate the susceptibility of arcobacters isolated in the Czech Republic. No information about antibiotic susceptibility and multidrug resistance of arcobacters isolated in the Czech Republic is available in the literature before now. The antimicrobial resistance of A. butzleri (n=80) and A. cryaerophilus (n=20) isolated from meat of animal origin, water sources and clinical samples was examined by the disk diffusion method. Arcobacters were resistant to one or more antimicrobial agents in 99% (99/100) of tested isolates. Most of the Arcobacter isolates were resistant to β-lactam antibiotics, i.e. ampicillin (81.0%), amoxicillin/clavulanic acid (28.0%), cefalotin (73.0%) and aztreonam (93.0%). Arcobacters were also frequently resistant to lincosamides, i.e. clindamycin (98.0%). Of the aminoglycosides, amikacin, gentamicin and tobramycin were evaluated to be the most effective antibiotics among those tested against arcobacters. These results demonstrate substantial resistance in Arcobacter isolates to 18 antimicrobial agents commonly used in medical and veterinary medicine. Multidrug resistance was found in 93.8% (75/80) of A. butzleri isolates and 70.0% (14/20) of A. cryaerophilus isolates.

Isolation, molecular identification and quinolone-susceptibility testing of Arcobacter spp. isolated from fresh vegetables in Spain

Some species of the Arcobacter genus are considered emerging foodborne and waterborne enteropathogens. However, the presence of Arcobacter spp. in vegetables very little is known, because most studies have focused on foods of animal origin. On the other hand, quinolones are considered as first-line drugs for the treatment of infection by campylobacteria in human patients, but few data are currently available about the resistance levels to these antibiotics among Arcobacter species. Therefore, the aim of this study was to investigate the presence and diversity of arcobacters isolated from fresh vegetables such as lettuces, spinaches, chards and cabbages. Resistance to quinolones of the isolates was also investigated.One hundred fresh vegetables samples purchased from seven local retail markets in Valencia (Spain) during eight months were analysed. The study included 41 lettuces, 21 spinaches, 34 chards and 4 cabbages. Samples were analysed by culture and by molecular methods before and after enrichment. By culture, 17 out of 100 analysed samples were Arcobacter positive and twenty-five isolates were obtained from them. Direct detection by PCR was low, with only 4% Arcobacter spp. positive samples. This percentage increased considerably, up 20%, after 48 h enrichment. By polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), 17 out of the 25 isolates were identified as A. butzleri and 8 as A. cryaerophilus. Only two A. butzleri isolates showed resistance to levofloxacin and ciprofloxacin. The sequencing of a fragment of the QRDR region of the gyrA gene from the quinolones-resistant isolates revealed the presence of a mutation in position 254 of this gene (C-T transition).This study is the first report about the presence of pathogenic species of Arcobacter spp. in chards and cabbages and confirms that fresh vegetables can act as transmission vehicle to humans. Moreover, the presence of A. butzleri quinolone resistant in vegetables could pose a potential public health risk.

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.

Isolation and characterization of Arcobacter spp. from fresh seafood and the aquatic environment

Arcobacter is an emerging pathogen associated with foods of animal origin. Members of the genus Arcobacter are increasingly being isolated from fish, shellfish and the aquatic environment. In the present study, we analyzed fish, shellfish and water samples for the presence of Arcobacter spp. by conventional isolation as well as by direct PCR on the enrichment broth. Of 100 samples comprising of 42 finfish, 34 shellfish and 24 water samples analyzed, Arcobacter spp. was isolated from 8 (19%) finfish, 5 (14.7%) shellfish and 5 (20.8%) water samples. Arcobacter DNA was detected in 24 (24%) samples by direct PCR on the enrichment broth. Based on m-PCR specific to different Arcobacter spp. and 16S rRNA sequence analyses, majority (19) of the isolates were identified as Arcobacter butzleri, while two isolates were Arcobacter mytili. All Arcobacter butzleri isolates harbored putative virulence genes cadF, ciaB, mviN, pldA, tlyA and cj1349. The two isolates of A. mytili harbored mviN and cj1349 genes only. The study highlights emerging problem of the contamination of aquatic environment and fresh seafood with potentially pathogenic Arcobacter spp.

Antimicrobial susceptibility testing of Arcobacter butzleri and Arcobacter cryaerophilus strains isolated from Belgian patients.

To evaluate the feasibility of different methods for susceptibility testing of human Arcobacter isolates, to assess susceptibility to antibiotics commonly used to treat diarrhoeal illness and to obtain MIC distribution data. One-hundred-and-six unique Arcobacter strains were collected during an epidemiological study on pathogens in gastroenteritis. Strains were identified by multiplex PCR and PCR-RFLP, and characterized by PFGE. Susceptibility to ampicillin, erythromycin, tetracycline, doxycycline, gentamicin and ciprofloxacin was determined using gradient strip and disc diffusion methodology. Optimal conditions for growth and incubation were tested. Azithromycin was tested with gradient strip diffusion on a subset of 40 strains. Sequence analysis of the quinolone resistance-determining region of gyrA was performed for a subset of 18 strains. Based on gradient diffusion results, most Arcobacter strains were susceptible to gentamicin (99%) and tetracycline (89%). Erythromycin (78%), ciprofloxacin (72%) and doxycycline (76%) retained moderate activity against Arcobacter spp. Only 9% of the strains were susceptible to ampicillin. Most Arcobacter butzleri strains were susceptible to ciprofloxacin (87%), whereas half of the Arcobacter cryaerophilus isolates (51%) showed high-level resistance (MIC >32 mg/L). MIC50 values were comparable for both macrolide antibiotics. Ciprofloxacin-resistant strains possessed an identical mutation in gyrA. Overall, categorical agreement between gradient and disc diffusion results was 60%. Gradient diffusion showed superior readability. Gradient diffusion methodology is preferred for routine susceptibility testing. Acquired resistance to fluoroquinolones was observed in A. cryaerophilus. Macrolides are not first-choice empirical antibiotics for Arcobacter infections. Tetracyclines can be suggested for treatment of documented Arcobacter-related gastrointestinal infections.

Occurrence of potentially pathogenic arcobacters in shellfish

Considering that several recent cases of human gastroenteritis have been associated with species from the Arcobacter genus, and that few data are currently available about the occurrence of this genus in Italian shellfish, the aim of the present study was to evaluate the occurrence of Arcobacter spp. and the presence of virulence-associated genes. The approach consisted of cultural and biomolecular (multiplex-PCR and 16S-RFLP) methods identifying isolates, followed by PCR assays aimed at the cadF, ciaB, cjl349, irgA, hecA putative virulence genes. Arcobacter spp. was detected in 16/70 (22.8%) shellfish samples. Specifically, Arcobacter spp. was highlighted in 10/42 (23.8%) mussel and in 6/28 (21.4%) clam samples. Subsequently, biomolecular assays revealed Arcobacter butzleri in 12/16 (75%) and Arcobacter cryaerophilus 1B in 4/16 (25%) isolates. PCRs aimed at the five putative virulence genes demonstrated widespread distribution of these genes among Arcobacter isolates and some differences from the results published by other authors. Our research provides more information regarding the health risks associated with the consumption of raw bivalve molluscs and underlines the need to implement an adequate control plan by performing intensive and continuous monitoring in order to guarantee human health.

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.