CemR atypical response regulator impacts energy conversion in Campylobacteria.

Campylobacter jejuni and Arcobacter butzleri are microaerobic food-borne human gastrointestinal pathogens that mainly cause diarrheal disease. These related species of the Campylobacteria class face variable atmospheric environments during infection and transmission, ranging from nearly anaerobic to aerobic conditions. Consequently, their lifestyles require that both pathogens need to adjust their metabolism and respiration to the changing oxygen concentrations of the colonization sites. Our transcriptomic and proteomic studies revealed that C. jejuni and A. butzleri, lacking a Campylobacteria-specific regulatory protein, C. jejuni Cj1608, or a homolog, A. butzleri Abu0127, are unable to reprogram tricarboxylic acid cycle or respiration pathways, respectively, to produce ATP efficiently and, in consequence, adjust growth to changing oxygen supply. We propose that these Campylobacteria energy and metabolism regulators (CemRs) are long-sought transcription factors controlling the metabolic shift related to oxygen availability, essential for these bacteria's survival and adaptation to the niches they inhabit. Besides their significant universal role in Campylobacteria, CemRs, as pleiotropic regulators, control the transcription of many genes, often specific to the species, under microaerophilic conditions and in response to oxidative stress. IMPORTANCE: C. jejuni and A. butzleri are closely related pathogens that infect the human gastrointestinal tract. In order to infect humans successfully, they need to change their metabolism as nutrient and respiratory conditions change. A regulator called CemR has been identified, which helps them adapt their metabolism to changing conditions, particularly oxygen availability in the gastrointestinal tract so that they can produce enough energy for survival and spread. Without CemR, these bacteria, as well as a related species, Helicobacter pylori, produce less energy, grow more slowly, or, in the case of C. jejuni, do not grow at all. Furthermore, CemR is a global regulator that controls the synthesis of many genes in each species, potentially allowing them to adapt to their ecological niches as well as establish infection. Therefore, the identification of CemR opens new possibilities for studying the pathogenicity of C. jejuni and A. butzleri.

Genes involved in the adhesion and invasion of Arcobacter butzleri.

Arcobacter butzleri is a foodborne pathogen that mainly causes enteritis in humans, but the number of cases of bacteraemia has increased in recent years. However, there is still limited knowledge on the pathogenic mechanisms of this bacterium. To investigate how A. butzleri causes disease, single knockout mutants were constructed in the cadF, ABU_RS00335, ciaB, and flaAB genes, which might be involved in adhesion and invasion properties. These mutants and the isogenic wild-type (WT) were then tested for their ability to adhere and invade human Caco-2 and HT29-MTX cells. The adhesion and invasion of A. butzleri RM4018 strain was also visualized by a Leica CTR 6500 confocal microscope. The adhesion and invasion abilities of mutants lacking the invasion antigen CiaB or a functional flagellum were lower than those of the WTs. However, the extent of the decrease varied depending on the strain and/or cell line. Mutants lacking the fibronectin (FN)-binding protein CadF consistently exhibited reduced abilities, while the inactivation of the other studied FN-binding protein, ABU_RS00335, led to a reduction in only one of the two strains tested. Therefore, the ciaB and flaAB genes appear to be important for A. butzleri adhesion and invasion properties, while cadF appears to be indispensable.

Pathogenicity assessment of Arcobacter butzleri isolated from Canadian agricultural surface water.

BACKGROUND: Water is considered a source for the transmission of Arcobacter species to both humans and animals. This study was conducted to assess the prevalence, distribution, and pathogenicity of A. butzleri strains, which can potentially pose health risks to humans and animals. Cultures were isolated from surface waters of a mixed-use but predominately agricultural watershed in eastern Ontario, Canada. The detection of antimicrobial resistance (AMR) and virulence-associated genes (VAGs), as well as enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) assays were performed on 913 A. butzleri strains isolated from 11 agricultural sampling sites. RESULTS: All strains were resistant to one or more antimicrobial agents, with a high rate of resistance to clindamycin (99%) and chloramphenicol (77%), followed by azithromycin (48%) and nalidixic acid (49%). However, isolates showed a significantly (p < 0.05) high rate of susceptibility to tetracycline (1%), gentamycin (2%), ciprofloxacin (4%), and erythromycin (5%). Of the eight VAGs tested, ciaB, mviN, tlyA, and pldA were detected at high frequency (> 85%) compared to irgA (25%), hecB (19%), hecA (15%), and cj1349 (12%) genes. Co-occurrence analysis showed A. butzleri strains resistant to clindamycin, chloramphenicol, nalidixic acid, and azithromycin were positive for ciaB, tlyA, mviN and pldA VAGs. ERIC-PCR fingerprint analysis revealed high genetic similarity among strains isolated from three sites, and the genotypes were significantly associated with AMR and VAGs results, which highlight their potential environmental ubiquity and potential as pathogenic. CONCLUSIONS: The study results show that agricultural activities likely contribute to the contamination of A. butzleri in surface water. The findings underscore the importance of farm management practices in controlling the potential spread of A. butzleri and its associated health risks to humans and animals through contaminated water.

Antibiotic-Resistant Arcobacter spp. in commercial and smallholder farm animals in Asante Akim North Municipality, Ghana and Korogwe Town Council, Tanzania: a cross-sectional study.

BACKGROUND: Arcobacter species are considered emerging foodborne pathogens that can potentially cause serious infections in animals and humans. This cross-sectional study determined the frequency of potentially pathogenic Arcobacter spp. in both commercial and smallholder farm animals in Ghana and Tanzania. A total of 1585 and 1047 (poultry and livestock) samples were collected in Ghana and Tanzania, respectively. Selective enrichment media, along with oxidase and Gram testing, were employed for isolation of suspected Arcobacter spp. and confirmation was done using MALDI-TOF MS. Antibiotic susceptibility was assessed through disk diffusion method and ECOFFs were generated, for interpretation, based on resulting inhibition zone diameters. RESULTS: The overall Arcobacter frequency was higher in Ghana (7.0%, n = 111) than in Tanzania (2.0%, n = 21). The frequency of Arcobacter in commercial farms in Ghana was 10.3% (n/N = 83/805), while in Tanzania, it was 2.8% (n/N = 12/430). Arcobacter was detected in only 3.6% (n/N = 28/780) of the samples from smallholder farms in Ghana and 1.5% (n/N = 9/617) of the samples from Tanzania. For commercial farms, in Ghana, the presence of Arcobacter was more abundant in pigs (45.1%, n/N = 37/82), followed by ducks (38.5%, n/N = 10/26) and quails (35.7%, n/N = 10/28). According to MALDI-TOF-based species identification, Arcobacter butzleri (91.6%, n/N = 121/132), Arcobacter lanthieri (6.1%, n/N = 8/132), and Arcobacter cryaerophilus (2.3%, n/N = 3/132) were the only three Arcobacter species detected at both study sites. Almost all of the Arcobacter from Ghana (98.2%, n/N = 109/111) were isolated during the rainy season. The inhibition zone diameters recorded for penicillin, ampicillin, and chloramphenicol allowed no determination of an epidemiological cut-off value. However, the results indicated a general resistance to these three antimicrobials. Multidrug resistance was noted in 57.1% (n/N = 12/21) of the Arcobacter isolates from Tanzania and 45.0% (n/N = 50/111) of those from Ghana. The type of farm (commercial or smallholder) and source of the sample (poultry or livestock) were found to be associated with multi-drug resistance. CONCLUSIONS: The high levels of MDR Arcobacter detected from farms in both countries call for urgent attention and comprehensive strategies to mitigate the spread of antimicrobial resistance in these pathogens.

Virulence genotype and phenotype of two clinical isolates of Arcobacter butzleri obtained from patients with different pathologies.

The surge in human arcobacteriosis has increased interest in determining the mechanisms involved in the pathogenesis of Arcobacter butzleri. Here, genomic analyses and in vitro Caco-2 infection, motility, urease and antimicrobial susceptibility testing (AST) assays were used to characterise the virulence and antimicrobial resistance (AMR) determinants of strains HC-1, isolated from a patient with travellers' diarrhoea, and HC-2, isolated from another with pruritus. AMR determinants conferring resistance to tetracycline (tetO, present in both genomes) and to ampicillin and amoxicillin-clavulanic acid (bla3, present in HC-2) were identified. The same determinants associated with flagellum, chemotaxis, adhesion and invasion were detected in both, but HC-1 lacked eight flagellar genes. The urease cluster was only present in HC-1. Motility and urease tests confirmed the genetic differences between strains, but no genetic marker related to the inability of HC-2 to adhere and invade was identified. This inability could be conditioning the patient's pathology.

The occurrence of some foodborne pathogens recovered from poultry meat in Shahrekord, Iran.

Objective: Arcobacter butzleri, Listeria monocytogenes, Staphylococcus aureus, and Campylobacter jejuni are significant foodborne pathogens regarding the consumption of raw poultry meat. An existing survey was conducted to assess the occurrence of S. aureus, C. jejuni, A. butzleri, and L. monocytogenes in raw poultry meat samples. Materials and Methods: Ninety-four raw ostrich, turkey, chicken, and quail meat samples were collected and subjected to culture-based analysis. Staphylococcus aureus, C. jejuni, A. butzleri, and L. monocytogenes isolates were confirmed by standard biochemical techniques. Results: The occurrence of A. butzleri, C. jejuni, L. monocytogenes, and S. aureus in poultry meat samples was 11.45%, 17.70%, 1.04%, and 16.66%, respectively. L. monocytogenes was absent in chicken, turkey, and ostrich meat samples. Only one quail meat (4.16%) was positive for L. monocytogenes. The uppermost contamination rate with A. butzleri, C. jejuni, and S. aureus was found in chicken (25%), turkey (25%), and turkey (25%) meat samples, respectively. The concurrent occurrence of A. butzleri + C. jejuni + S. aureus bacteria amid the examined poultry meat samples was 2.08%. Conclusion: This is an initial report of A. butzleri, S. aureus, C. jejuni, and L. monocytogenes in poultry meat samples. Adequate cooking of poultry meat can diminish foodborne diseases due to A. butzleri, S. aureus, L. monocytogenes, and C. jejuni bacteria, and these species may constitute a public health problem.

Widespread Multidrug Resistance of Arcobacter butzleri Isolated from Clinical and Food Sources in Central Italy.

The Arcobacter genus comprises a group of bacteria widely distributed in different habitats that can be spread throughout the food chain. Fluoroquinolones and aminoglycosides represent the most common antimicrobial agents used for the treatment of Arcobacter infections. However, the increasing trend of the antimicrobial resistance of this pathogen leads to treatment failures. Moreover, the test implementation and interpretation are hindered by the lack of reference protocols and standard interpretive criteria. The purpose of our study was to assess the antibiotic resistance pattern of 17 A. butzleri strains isolated in Central Italy from fresh vegetables, sushi, chicken breast, and clinical human samples to provide new and updated information about the antimicrobial resistance epidemiology of this species. Antimicrobial susceptibility testing was carried out by the European Committee on Antimicrobial Susceptibility Testing (EUCAST)'s disc diffusion method. All the strains were multidrug resistant, with 100% resistance to tetracyclines and cefotaxime (third generation cephalosporins). Some differences were noticed among the strains, according to the isolation source (clinical isolates, food of animal origin, or fresh vegetables), with a higher sensitivity to streptomycin detected only in the strains isolated from fresh vegetables. Our data, together with other epidemiological information at the national or European Union (EU) level, may contribute to developing homogeneous breakpoints. However, the high prevalence of resistance to a wide range of antimicrobial classes makes this microorganism a threat to human health and suggests that its monitoring should be considered by authorities designated for food safety.

Genomic Characterization of Arcobacter butzleri Strains Isolated from Various Sources in Lithuania.

Arcobacter (A.) butzleri, the most widespread species within the genus Arcobacter, is considered as an emerging pathogen causing gastroenteritis in humans. Here, we performed a comparative genome-wide analysis of 40 A. butzleri strains from Lithuania to determine the genetic relationship, pangenome structure, putative virulence, and potential antimicrobial- and heavy-metal-resistance genes. Core genome single nucleotide polymorphism (cgSNP) analysis revealed low within-group variability (≤4 SNPs) between three milk strains (RCM42, RCM65, RCM80) and one human strain (H19). Regardless of the type of input (i.e., cgSNPs, accessory genome, virulome, resistome), these strains showed a recurrent phylogenetic and hierarchical grouping pattern. A. butzleri demonstrated a relatively large and highly variable accessory genome (comprising of 6284 genes with around 50% of them identified as singletons) that only partially correlated to the isolation source. Downstream analysis of the genomes resulted in the detection of 115 putative antimicrobial- and heavy-metal-resistance genes and 136 potential virulence factors that are associated with the induction of infection in host (e.g., cadF, degP, iamA), survival and environmental adaptation (e.g., flagellar genes, CheA-CheY chemotaxis system, urease cluster). This study provides additional knowledge for a better A. butzleri-related risk assessment and highlights the need for further genomic epidemiology studies in Lithuania and other countries.

Outbreak of Arcobacter butzleri? An emerging enteropathogen.

BACKGROUND: Arcobacter butzleri is a gram-negative rod, with microaerobic growth at an optimal temperature of 37°C. It was reported to be the fourth most common Campylobacter-like organism isolated from patients with diarrhoea. OBJECTIVE: Characterise a potential outbreak of A. butzleri detected in a short period of time in the University Hospital Marqués de Valdecilla. METHODS: Eight strains of A. butzleri were detected in our hospital in only two months. Isolates were identified by MALDI-TOF MS system and 16S rDNA sequencing. Enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) and Pulsed Field Gel Electrophoresis (PFGE) were carried out to assess clonal relationship. Gradient strips (Etest) were used to determine susceptibility by agar diffusion. RESULTS: ERIC-PCR and PFGE confirmed the lack of clonal relationship between strains. Erythromycin or ciprofloxacin might be appropriate for antibiotic treatment of infections. CONCLUSIONS: A. butzleri is an emerging pathogen with increasing incidence, and may be underestimated.

Comparison of Two Culture-Based Detection Systems for the Isolation of Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii in Raw Ground Poultry.

Arcobacters are emerging pathogens that have been underestimated due to a lack of a standardized isolation method. The aim of this research was to evaluate the ability to isolate Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii using two Arcobacter-specific culture detection systems: (i) the Houf broth and modified charcoal cefoperazone deoxycholate agar supplemented with cefoperazone, amphotericin B, and teicoplanin (HB/mCCDA+CAT), and (ii) the Nguyen-Restaino-Juárez Arcobacter enrichment broth and chromogenic agar (NRJ-B/M). Both detection systems were evaluated for productivity ratio, sensitivity, and specificity. As a result, the productivity ratio for both plating agars were >90%, which indicates that the selective agents used in the two plating agars did not inhibit Arcobacter growth. Moreover, sensitivity evaluations using artificially inoculated retail ground poultry (n = 780) determined that both detection systems were able to isolate A. butlzeri with >95% sensitivity at the 0.1 and 1.0-2.0 CFU/g detection level. The sensitivity in A. cryaerophilus isolation was higher for NRJ-B/M (78.0% at 0.1 CFU/g; 95.1% at 1.0-2.0 CFU/g) when compared with HB/mCCDA+CAT (34.1% at 0.1 CFU/g; 51.2% at 1.0-2.0 CFU/g). Both detection systems resulted in <50% sensitivity when isolating A. skirrowii at 0.1 and 1.0-2.0 CFU/g; however, the sensitivity for NRJ-B/M was significantly higher than HB/mCCDA+CAT. At the detection level of 5.0 CFU/g, both detection systems were able to isolate A. skirrowii with 100% sensitivity. Specificity comparisons using uninoculated ground poultry samples (n = 40) indicated the growth of background microbiota were significantly inhibited or could be easily differentiated on NRJ-B/M (90.0%, specificity) when compared with HB/mCCDA+CAT (30.0%, specificity). Overall, these results show that the NRJ-B/M detection system is a more sensitive and specific detection system when isolating Arcobacter spp. from ground chicken.

Outbreak of Arcobacter butzleri? An emerging enteropathogen / Brote de Arcobacter butzleri? Un enteropatógeno emergente

Background: Arcobacter butzleri is a gram-negative rod, with microaerobic growth at an optimal temperature of 37°C. It was reported to be the fourth most common Campylobacter-like organism isolated from patients with diarrhoea. Objective: Characterise a potential outbreak of A. butzleri detected in a short period of time in the University Hospital Marqués de Valdecilla. Methods: Eight strains of A. butzleri were detected in our hospital in only two months. Isolates were identified by MALDI-TOF MS system and 16S rDNA sequencing. Enterobacterial repetitive intergenic consensus-PCR (ERIC-PCR) and Pulsed Field Gel Electrophoresis (PFGE) were carried out to assess clonal relationship. Gradient strips (Etest) were used to determine susceptibility by agar diffusion. Results: ERIC-PCR and PFGE confirmed the lack of clonal relationship between strains. Erythromycin or ciprofloxacin might be appropriate for antibiotic treatment of infections. Conclusions: A. butzleri is an emerging pathogen with increasing incidence, and may be underestimated.(AU)

Antecedentes: Arcobacter butzleri es un bacilo gramnegativo, con crecimiento microaerófilo a una temperatura óptima de 37°C. Ha sido descrito como el cuarto organismo asociado a Campylobacter más frecuentemente aislado de pacientes con diarrea. Objetivo: Caracterizar un potencial brote de A. butzleri detectado en el Hospital Universitario Marqués de Valdecilla. Métodos: Se detectaron 8 cepas de A. butzleri en nuestro hospital en solo 2 meses. Los aislamientos fueron identificados con MALDI-TOF MS y secuenciación del ARNr 16S. Se llevó a cabo la PCR basada en secuencia de consenso intergénica repetitiva de enterobacterias(ERIC-PCR) y electroforesis en campo pulsado (PFGE) para asegurar la relación clonal. Para determinar la sensibilidad se usaron tiras de gradiente (Etest®) por difusión en agar. Resultados: ERIC-PCR y PFGE confirmaron la falta de relación clonal entre las cepas. Eritromicina o ciprofloxacino podrían ser apropiados para el tratamiento antibiótico de estas infecciones. Conclusiones: A. butzleri es un patógeno emergente con un aumento en la incidencia, y podría estar subestimado.(AU)

Molecular characterization of Arcobacter butzleri isolates from poultry in rural Ghana.

In recent years, Arcobacter butzleri has gained clinical significance as an emerging diarrheagenic pathogen associated with poultry and water reservoirs. The full clinical significance of Arcobacter remains rather speculative due to variable virulence and antibiotic susceptibility of individual strains. The aims of the present study were (i) to identify antibiotic resistance genes (ARGs) in the genome sequences of two multidrug-resistant A. butzleri isolates, (ii) to use multilocus-sequence typing (MLST) to generate a guiding phylogeny of A. butzleri isolates collected in Kumasi, Ghana, (iii) to examine the distribution of ARGs in the test cohort, and (iv) to assess the strain's virulence and possible antibiotic treatment options for arcobacteriosis based on the genome sequences and the ARG distribution. A total of 48 A. butzleri isolates obtained from poultry were included in the analysis. These isolates were genotyped by MLST and the antibiotic susceptibilities of isolates to ampicillin, ciprofloxacin, tetracycline, gentamicin, and erythromycin were tested by disk diffusion. Whole genome sequence data of two multidrug-resistant (MDR) A. butzleri isolates were obtained by a combination of single-molecule real-time (SMRT) and Illumina sequencing technology. A total of 14 ARGs were identified in the two generated genome sequences. For all 48 isolates, the frequency of these 14 ARGs was investigated by PCR or amplicon sequencing. With 44 different sequence types found among 48 isolates, strains were phylogenetically heterogeneous. Four of 48 isolates showed an ARG constellation indicating a multidrug-resistant phenotype. The virulence genes in the two A. butzleri genomes showed that the species might be characterized by a somewhat lower virulence as Campylobacter species. The phenotypic susceptibility data combined with the distribution of the particular ARGs especially oxa-464 and the T81I point mutation of the quinolone resistance determining region (QRDR) in a significant percentage of isolates indicated that macrolides and tetracycline can be recommended for calculated antibiotic treatment of arcobacteriosis in Ghana, but not ampicillin and quinolones.

Transcriptome Analysis of Arcobacter butzleri Infection in a Mucus-Producing Human Intestinal In Vitro Model.

Arcobacter butzleri is a foodborne pathogen belonging to the Arcobacteraceae family. This Gram-negative bacterium is found in water, food, and various organisms, including farm animals, clams, and fish. Moreover, A. butzleri has been isolated from human stool samples, where it was associated with gastrointestinal symptoms such as diarrhea. The present study focused on the transcriptome analysis of three A. butzleri strains isolated from human stools and displaying variable virulence potential in vitro. We used a mucus-producing human intestinal in vitro model (Caco-2/HT29-MTX-E12) to study the colonization and invasion abilities of the three A. butzleri strains. The ability of all three A. butzleri strains to colonize our in vitro model system was subsequently confirmed. Moreover, transcriptomics showed the upregulation of putative virulence genes. Among these genes, tonB, exbB, and exbD, which belong to the same operon, were upregulated in strain LMG 11119, which also had the greatest colonization ability. Moreover, genes not currently considered A. butzleri virulence genes were differentially expressed during cell model colonization. The main functions of these genes were linked to organic acid metabolism and iron transport and particularly to the function of the TonB complex. IMPORTANCE Recent advancements in the genomic characterization of A. butzleri revealed putative virulence genes and highlighted the possible pathogenic mechanisms used by this foodborne pathogen. It is therefore possible to study the transcriptomes of these bacteria to explore possible virulence mechanisms under conditions that mimic the infection process. The transcriptome and colonization/invasion analyses that we performed in this study enabled the evaluation of A. butzleri-mediated infection of the mucus-producing human intestinal in vitro model. We confirmed the upregulation of previously proposed virulence genes in the A. butzleri strains. In addition, we identified the differential expression of a number of other genes, which are not currently thought to be associated with virulence, in three A. butzleri strains during infection of mucus-producing human epithelial cells. Changes in the concentration of acetic acid and the upregulation of genes associated with organic acid metabolism during host-pathogen contact were also observed. These findings highlight the importance of previously unreported genes in the virulence mechanisms of A. butzleri.

Arcobacter butzleri Biofilms: Insights into the Genes Beneath Their Formation.

Arcobacter butzleri, the most prevalent species of the genus, has the demonstrated ability to adhere to various surfaces through biofilm production. The biofilm formation capability has been related to the expression of certain genes, which have not been characterized in A. butzleri. In order to increase the knowledge of this foodborne pathogen, the aim of this study was to assess the role of six biofilm-associated genes in campylobacteria (flaA, flaB, fliS, luxS, pta and spoT) in the biofilm formation ability of A. butzleri. Knockout mutants were constructed from different foodborne isolates, and static biofilm assays were conducted on polystyrene (PS), reinforced glass and stainless steel. Additionally, motility and Congo red binding assays were performed. In general, mutants in flaAB, fliS and luxS showed a decrease in the biofilm production irrespective of the surface; mutants in spoT showed an increase on stainless steel, and mutants in pta and spoT showed a decrease on reinforced glass but an increase on PS. Our work sheds light on the biofilm-related pathogenesis of A. butzleri, although future studies are necessary to achieve a satisfactory objective.

Survival capacity of Arcobacter butzleri at different incubation temperatures in drinking water

Arcobacter represents a zoonotic emerging pathogen with increasing importance for public health and drinking water has been cited as a major risk factor for its dissemination. The aim of this work was to evaluate the survival capacity of Arcobacter in different water matrixes stored at different temperatures. Three different water matrixes were used, including potable water with a chlorine concentration of 0,5 mg/mL, non-chlorinated water and non-chlorinated water added with an 11% of organic matter. Each matrix was inoculated in a 1/10 proportion with 103 and 105 Arcobacter pools, divided into 4 different subsamples, in order to be incubated at 0°C, 5°C, 12 °C and 25°C by up to 15 days. The presence of Arcobacter in each matrix was determined on days 1, 3, 5, 7, 9, 11, 13 and 15. Results obtained show that this bacterium can survive in all the water matrixes evaluated, regardless of the presence or not of residual disinfecting agent. Also, the amount of CFU/mL inoculated in water correlates with the number of bacteria that can survive on it, and that incubation temperature has a significant effect over the bacterial survival.

First case of diarrhea due to Aliarcobacter butzleri (formerly Arcobacter butzleri) in Ecuador.

The first case of acute watery diarrhea disease due to Aliarcobacter butzleri (formerly Arcobacter butzleri) in Ecuador is reported. An infant presented with moderate protein-calorie malnutrition, dehydration and anemia. A curved Gram-negative organism was isolated from stools, having been preliminarily identified by phenotypic characteristics. Definitive identification was achieved by multiplex PCR. Aliarcobacter butzleri was the only pathogenic microorganism isolated. No other entero-pathogens, enterovirus or parasites were found. Our findings strongly suggest that in this specific case, A. butzleri was the etiological agent. Further investigations are needed to develop standardized diagnostic protocols and to establish the prevalence and significance of Aliarcobacter infections in humans.

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 characterization of Arcobacter spp. from ready-to-eat vegetables produced in Southern Italy.

Given that the number of foodborne illness outbreaks linked to the consumption of ready-to-eat vegetables has been widely documented and considering that data on the occurrence of Arcobacter spp. in such foodstuffs are lacking, the aim of the present study was to evaluate the presence of Arcobacter spp. and the occurrence of virulence factors as well as to genotype Arcobacter spp. in ready-to-eat (RTE) vegetable samples, using cultural and biomolecular assays. Arcobacter spp. was detected in 16/110 (14.5%) samples, with A. butzleri being detected in 15/16 and A. cryaerophilus in 1/16 isolates. PCRs aimed at the nine putative virulence genes demonstrated widespread distribution of such genes among A. butzleri and A. cryaerophilus isolates. In addition, multilocus sequence type (MLST) analysis revealed a low genetic diversity within the arcobacters isolates. The results underline the need to develop an appropriate surveillance system based on biomolecular characterization for an integrated microbiological risk assessment of ready-toeat vegetables, and consequently of composite foods.

A New Method for Detection of Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii Using a Novel Chromogenic Agar.

ABSTRACT: Arcobacter species are gram-negative rods that have been implicated in food- and waterborne illness. Although various cultural isolation methods have been proposed, the current procedures are unable to fully suppress the growth of background microbiota present in food samples, which inhibits Arcobacter isolation. The purpose of this study was to develop a selective enrichment broth and chromogenic plating medium to detect three Arcobacter species that have been recognized as emerging foodborne pathogens: Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii. The developed Nguyen-Restaino-Juárez (NRJ) Arcobacter detection system consists of a selective enrichment broth (NRJ-B) and a selective-differential plating medium (NRJ-M). The protocol of the detection method was determined by evaluating the growth of A. butzleri, A. cryaerophilus, and A. skirrowii under various temperatures (30, 35, and 42°C) and incubation (aerobic, microaerophilic, and anaerobic) conditions. Additionally, 47 Arcobacter strains and 39 non-Arcobacter strains were tested in inclusivity and exclusivity evaluations of NRJ-B and NRJ-M. Overall, the study determined that the optimal growth conditions of Arcobacter species using the NRJ Arcobacter detection system were aerobic incubation at 30°C. NRJ-B supported good growth of A. butzleri, A. cryaerophilus, and A. skirrowii while effectively suppressing the growth of non-Arcobacter strains after 48 h. Furthermore, NRJ-M yielded 97.8% inclusivity and 100.0% exclusivity using the tested strains and resulted in salmon-pigmented Arcobacter colonies (1.0 to 1.5 mm in diameter) after 72 h. The novel protocol is the first to develop a chromogenic plating medium for the isolation of Arcobacter species. This simple and accurate test method would greatly contribute to understanding the distribution of pathogenic Arcobacter species in food samples.

Genetic Characteristics and Antimicrobial Susceptibility of Arcobacter butzleri Isolates from Raw Chicken Meat and Patients with Diarrhea in China.

Arcobacter is an emerging foodborne pathogen worldwide. In this study, the prevalence, antimicrobial susceptibility and genetic characteristics of Arcobacter from different sources were investigated. Eighteen A. butzleri isolates were obtained from 60 raw chicken meat samples (16/60, 27%) and 150 patients with diarrhea (2/150, 1.3%). The resistance ratios to nalidixic acid, ciprofloxacin, clindamycin, chloramphenicol, and florfenicol were 83.33% (15/18), 38.89% (7/18), 38.89% (7/18), 33.33% (6/18) and 33.33% (6/18), respectively. We performed whole genome sequencing of the 18 isolates, and we predicted antibiotic resistance genes and virulence factors by using assembled genomes through blastx analysis. Two resistance genes, bla OXA-464 and tet(H), and the C254T mutation in gyrA, were identified in the genomes of some resistant isolates. Furthermore, virulence genes, such as flgG, flhA, flhB, fliI, fliP, motA, cadF, cjl349, ciaB, mviN, pldA and tlyA, were found in all strains, whereas hecA, hecB and iroE were found in only some strains. Phylogenetic tree analysis of A. butzleri isolates on the basis of the core-genome single nucleotide polymorphisms showed that two isolates from patients with diarrhea clustered together, separately from the isolates from raw chicken and the chicken strains. This study is the first comprehensive analysis of Arcobacter isolated in Beijing.