Arcobacter Butzleri Research Articles

Fate of antibiotic resistance genes and their associations with bacterial community in livestock breeding wastewater and its receiving river water

Large amounts of antibiotics are currently used in livestock breeding, which is the main driving factor contributing to the occurrence, spread and proliferation of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in the environment. In this study, high-throughput sequencing based metagenomic approaches were employed to characterize the tempo-spacial changes of antibiotic resistome, bacterial community and their correlations in pig farming wastewater and its receiving river. A total of 194 ARG subtypes within 14 ARG types were detectable in all the samples, and their total relative abundance increased in the river water after receiving wastewater discharge, while decreased in the downstream river water. Network analysis showed that 25.26% ARGs within the same type or among the different types showed higher incidences of non-random co-occurrence. The wastewater discharge evidently increased bacterial diversity and induced bacterial community shift in the receiving river water. The genera of Treponema, Prevotella, Pseudomonas, Bacteroides, Oscillibacter and Acholeplasma dominated in the wastewater samples and almost disappeared in the receiving river water, but bacterial pathogens Clostridium difficile and Arcobacter butzleri still occurred in the receiving water. Correlation analysis and host analysis consistently showed that the changes in the abundances of several key genera like Prevotella and Treponema were significantly and positively correlated with the antibiotic resistome alteration. Variation partitioning analysis indicated that bacterial community played a more important role in the resistome alteration than mobile genetic elements. This study may help to understand the correlations among antibiotic resistome, microbiota and environmental conditions in the wastewater-receiving river water.

Antimicrobial susceptibility testing of Arcobacter butzleri: development and application of a new protocol for broth microdilution.

To develop a standard reference broth microdilution method for antimicrobial susceptibility testing (AST) of Arcobacter butzleri. The protocol was subsequently applied to a collection of A. butzleri isolates from different sources. Broth microdilution susceptibility testing was performed on eight A. butzleri isolates in three media: non-supplemented CAMHB, CAMHB + 2% FBS and CAMHB + 5% FBS. The MIC values were read after 24 and 48 h of incubation at 35 ± 2 °C in ambient air. A logistic regression model was used to determine the combination of medium and incubation time yielding the most homogeneous results. Subsequently, the protocol was applied to 65 A. butzleri isolates to determine their MICs of 31 antimicrobial agents. The statistical analysis revealed that the most homogeneous MIC values were obtained with CAMHB + 5% FBS and reading of MIC values after 24 h of incubation. The standardized method was successful for AST of all 65 A. butzleri isolates. MIC values were distributed unimodally for most antimicrobial agents. However, one field isolate showed elevated MIC values of gentamicin, streptomycin, tetracycline and trimethoprim/sulfamethoxazole. This study presents a new protocol for AST of A. butzleri by broth microdilution and shows the distribution of MIC values of 31 antimicrobial agents for a collection of A. butzleri isolates from different origins.

Characterization of the emerging zoonotic pathogen Arcobacter thereius by whole genome sequencing and comparative genomics.

Four Arcobacter species have been associated with human disease, and based on current knowledge, these Gram negative bacteria are considered as potential food and waterborne zoonotic pathogens. At present, only the genome of the species Arcobacter butzleri has been analysed, and still little is known about their physiology and genetics. The species Arcobacter thereius has first been isolated from tissue of aborted piglets, duck and pig faeces, and recently from stool of human patients with enteritis. In the present study, the complete genome and analysis of the A. thereius type strain LMG24486T, as well as the comparative genome analysis with 8 other A. thereius strains are presented. Genome analysis revealed metabolic pathways for the utilization of amino acids, which represent the main source of energy, together with the presence of genes encoding for respiration-associated and chemotaxis proteins. Comparative genome analysis with the A. butzleri type strain RM4018 revealed a large correlation, though also unique features. Furthermore, in silico DDH and ANI based analysis of the nine A. thereius strains disclosed clustering into two closely related genotypes. No discriminatory differences in genome content nor phenotypic behaviour were detected, though recently the species Arcobacter porcinus was proposed to encompass part of the formerly identified Arcobacter thereius strains. The report of the presence of virulence associated genes in A. thereius, the presence of antibiotic resistance genes, verified by in vitro susceptibility testing, as well as other pathogenic related relevant features, support the classification of A. thereius as an emerging pathogen.

Functionalized Fullerene Targeting Human Voltage-Gated Sodium Channel, hNav1.7.

Mutations of hNav1.7 that cause its activities to be enhanced contribute to severe neuropathic pain. Only a small number of hNav1.7 specific inhibitors have been identified, most of which interact with the voltage-sensing domain of the voltage-activated sodium ion channel. In our previous computational study, we demonstrated that a [Lys6]-C84 fullerene binds tightly (affinity of 46 nM) to NavAb, the voltage-gated sodium channel from the bacterium Arcobacter butzleri. Here, we extend this work and, using molecular dynamics simulations, demonstrate that the same [Lys6]-C84 fullerene binds strongly (2.7 nM) to the pore of a modeled human sodium ion channel hNav1.7. In contrast, the fullerene binds only weakly to a mutated model of hNav1.7 (I1399D) (14.5 mM) and a model of the skeletal muscle hNav1.4 (3.7 mM). Comparison of one representative sequence from each of the nine human sodium channel isoforms shows that only hNav1.7 possesses residues that are critical for binding the fullerene derivative and blocking the channel pore.

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.

Study of Biofilm Formation Ability of Foodborne Arcobacter butzleri under Different Conditions

The transmission of Arcobacter butzleri, an emerging food- and waterborne pathogen, is possibly favored by its ability to adhere to abiotic surfaces. In this study, we assessed the biofilm formation ability of 42 A. butzleri isolates recovered from different food products. Overall, nine isolates (21.4%) were able to adhere to polystyrene. Among them, a chicken-derived isolate was classified as strongly adherent. Based on the chi-square test, no relation was found between the adhesive abilities of the isolates and their source (P > 0.05). An aerobic atmosphere enhanced the adhesion ability of the majority of the adherent isolates (66.7%), because when tested in microaerobic conditions, a t test indicated that only three isolates increased their biofilm formation ability significantly (P < 0.05). In addition, seven (77.8%) of these nine isolates were able to adhere to glass surfaces, and viable cells were recovered from all the stainless steel coupons tested. Therefore, our results confirm the biofilm formation ability of A. butzleri, which may be influenced by the incubation atmosphere and the abiotic surface.

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.

Arcobacter spp. in fecal samples from Brazilian farmed caimans (Caiman yacare, Daudin 1802).

The aim of this study was to perform the identification and molecular characterization of Arcobacter cryaerophilus and Arcobacter butzleri isolated from caiman (Caiman yacare), kept at a production farm, in Brazil. Forty fecal samples were analyzed. After isolation and identification, 21/40 strains of A. butzleri and 19/40 strains of A. cryaerophilus were subjected to PCR for potential virulence gene detection. The results of the PCR showed 38/40 strains positive for the cadF, cj1349, ciaB, and tlyA genes, 39/40 strains positive for the pldA gene, and 40/40 strains positive for the mviN gene. None of the strains presented the irgA gene. Hemagglutinin (hecA gene) and hemolysin (hecB) genes were detected in 21/40 and 16/40 strains, respectively. The SE-AFLP showed a great genetic diversity, but some clonally groups were disseminated in various tanks. These data reveal that the strains presented the same virulence traits described from Arcobacter isolated from food-borne disease in humans.

Application of long amplicon propidium monoazide-PCR to assess the effects of temperature and background microbiota on pathogens in river water.

The decay rates of enteric waterborne pathogens were evaluated following the introduction of Yersinia enterocolitica, Salmonella enterica, Campylobacter jejuni and Arcobacter butzleri into river water at different temperatures (5, 15 and 25°C) for a period of 28 days. To improve the accuracy of the results a molecular viability assay, long amplicon propidium monoazide-polymerase chain reaction (PMA-PCR), was used to quantify the viable cell concentration and results from PCR with and without PMA were compared. As well, the effect of background microbiota was assessed for Y. enterocolitica and S. enterica by inoculating cells into sterile and non-sterile river water. Cell persistence was improved by up to 4 log for Y. enterocolitica and 4.5 log for S. enterica in sterile river water compared to natural river water, showing that the autochthonous biological activity in river water can accelerate the die-off of introduced bacteria. Results also showed that low temperature significantly improved the persistence of all four target bacteria in non-sterile river water. There was a more rapid decline in cell concentration in samples with PMA pretreatment; therefore using PMA-PCR analysis can provide more reliable data on viable/active enteric bacteria in aquatic microcosms and allows for improved assessment of pathogens in the environment.

Detection, Identification, and Antimicrobial Susceptibility of Arcobacter spp. Isolated from Shellfish in Spain.

This work aimed to determine the presence of Arcobacter spp. in shellfish and to determine its susceptibility to quinolones. One hundred samples (41 mussels, 37 clams, and 22 cockles) were purchased from different local retail shops in Valencia, Spain, from September 2013 to June 2015. All samples were analyzed simultaneously by culture, after an enrichment step, and by polymerase chain reaction (PCR), directly and after enrichment. The susceptibility to levofloxacin and ciprofloxacin of the isolates was tested using the disk-diffusion test and E-test strips method. To clarify the mechanism of quinolone resistance, a fragment of the quinolone resistance-determining region of the gyrA gene was sequenced. Thirty-seven samples were positive and 49 isolates were obtained by culture, and Arcobacter spp. DNA was detected in 32% of the samples by PCR. However, after 48-h enrichment, the number of positive samples increased, and 68 of the 100 samples yielded the specific Arcobacter spp. PCR product. In addition, 49 isolates were identified by PCR-restriction fragment length polymorphism. The most commonly found species was Arcobacter butzleri (25 isolates, 51.03%) followed by Arcobacter cryaerophilus (19 isolates, 38.77%) and Arcobacter defluvii (5 isolates, 10.20%). Only three isolates of A. butzleri were resistant to both antibiotics. A mutation C to T transition in the position 254 of the gyrA gene was present in the three resistant isolates. This study confirms that pathogenic arcobacters are frequently found in edible shellfish samples. Moreover, this is the first time that A. butzleri and A. cryaerophilus have been isolated from cockles.

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.

Isolation of Campylobacter spp. from Client-Owned Dogs and Cats, and Retail Raw Meat Pet Food in the Manawatu, New Zealand.

Campylobacter causes acute gastroenteritis in people worldwide and is frequently isolated from food, animals and the environment. The disease is predominately food-borne but many routes of transmission and sources of infection have been described, including contact with pets. The prevalence of Campylobacter spp. in dogs and cats varies widely, and data on New Zealand pets are limited. This study aimed to investigate the prevalence of Campylobacter spp. in dogs, cats and retail raw meat pet food products in New Zealand and to characterize Campylobacter jejuni isolates using multilocus sequence typing (MLST). Ninety dogs and 110 cats examined at the Massey University Veterinary Teaching Hospital for elective procedures, and fifty locally purchased retail raw meat pet diets were sampled. Two culture protocols combining Bolton broth enrichment and mCCDA and CAT agars in a microaerobic atmosphere at 42°C and 37°C with species identification using PCR were performed. The prevalence of Campylobacter spp., C.jejuni, Campylobacter upsaliensis and Campylobacter helveticus was 36%, 13%, 23% and 1% in dogs and 16%, 5%, 5% and 7% in cats, respectively. One dog had Campylobacter lari confirmed, and three dogs and one cat had multiple Campylobacter spp. detected. Significantly more animals tested positive using CAT than mCCDA agar (P<0.001). Being neutered, vaccinated for Bordetella bronchiseptica, fed dry diets and brought in for neutering were protective factors for dogs, whereas attendance for dental treatment was a risk factor for cats. Campylobacter spp. were isolated from 28%, C.jejuni 22%, C.lari 6% and Campylobacter coli 6% of food samples. Six isolates positive by Campylobacter genus PCR were identified as Arcobacter butzleri. Poultry meat was more likely to be positive than non-poultry meat (P=0.006). Of the 13 C.jejuni pet isolates with full MLST profiles, eight were of different sequence types (ST) and all nine food isolates were of different STs.

Unique and Universal Features of Epsilonproteobacterial Origins of Chromosome Replication and DnaA-DnaA Box Interactions.

In bacteria, chromosome replication is initiated by the interaction of the initiator protein DnaA with a defined region of a chromosome at which DNA replication starts (oriC). While DnaA proteins share significant homology regardless of phylogeny, oriC regions exhibit more variable structures. The general architecture of oriCs is universal, i.e., they are composed of a cluster of DnaA binding sites, a DNA-unwinding element, and sequences that bind regulatory proteins. However, detailed structures of oriCs are shared by related species while being significantly different in unrelated bacteria. In this work, we characterized Epsilonproteobacterial oriC regions. Helicobacter pylori was the only species of the class for which oriC was characterized. A few unique features were found such as bipartite oriC structure, not encountered in any other Gram-negative species, and topology-sensitive DnaA-DNA interactions, which have not been found in any other bacterium. These unusual H. pylori oriC features raised questions of whether oriC structure and DnaA-DNA interactions are unique to this bacterium or whether they are common to related species. By in silico and in vitro analyses we identified putative oriCs in three Epsilonproteobacterial species: pathogenic Arcobacter butzleri, symbiotic Wolinella succinogenes, and free-living Sulfurimonas denitrificans. We propose that oriCs typically co-localize with ruvC-dnaA-dnaN in Epsilonproteobacteria, with the exception of Helicobacteriaceae species. The clusters of DnaA boxes localize upstream (oriC1) and downstream (oriC2) of dnaA, and they likely constitute bipartite origins. In all cases, DNA unwinding was shown to occur in oriC2. Unlike the DnaA box pattern, which is not conserved in Epsilonproteobacterial oriCs, the consensus DnaA box sequences and the mode of DnaA-DnaA box interactions are common to the class. We propose that the typical Epsilonproteobacterial DnaA box consists of the core nucleotide sequence 5′-TTCAC-3′ (4–8 nt), which, together with the significant changes in the DNA-binding motif of corresponding DnaAs, determines the unique molecular mechanism of DnaA-DNA interaction. Our results will facilitate identification of oriCs and subsequent identification of factors which regulate chromosome replication in other Epsilonproteobacteria. Since replication is controlled at the initiation step, it will help to better characterize life cycles of these species, many of which are considered as emerging pathogens.

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.

Presence of Arcobacter species in pet cats and dogs in the Czech Republic

This study was conducted to evaluate the occurrence of the genus Arcobacter in cats and dogs in the Czech Republic. These animals may be carriers of the bacteria and potential sources of human infection. Oral smears were collected from animals using smear swabs and brushes. Based on previous studies, commercially available DNA kits were used for DNA isolation. Samples were analysed using polymerase chain reaction (PCR) and evaluated using gel electrophoresis. Overall, 178 oral smears were tested, of which 108 were from dogs and 70 were from cats. Out of all smears, five were positive, of which four samples were from dogs and one from a cat. In all five positive cases, PCR confirmed the presence of Arcobacter butzleri. In follow-up sampling, the presence of Arcobacter butzleri was demonstrated in two samples from a dog.

The Immunopathogenic Potential of Arcobacter butzleri - Lessons from a Meta-Analysis of Murine Infection Studies.

BackgroundOnly limited information is available about the immunopathogenic properties of Arcobacter infection in vivo. Therefore, we performed a meta-analysis of published data in murine infection models to compare the pathogenic potential of Arcobacter butzleri with Campylobacter jejuni and commensal Escherichia coli as pathogenic and harmless reference bacteria, respectively.Methodology / Principal FindingsGnotobiotic IL-10-/- mice generated by broad-spectrum antibiotic compounds were perorally infected with A. butzleri (strains CCUG 30485 or C1), C. jejuni (strain 81-176) or a commensal intestinal E. coli strain. Either strain stably colonized the murine intestines upon infection. At day 6 postinfection (p.i.), C. jejuni infected mice only displayed severe clinical sequelae such as wasting bloody diarrhea. Gross disease was accompanied by increased numbers of colonic apoptotic cells and distinct immune cell populations including macrophages and monocytes, T and B cells as well as regulatory T cells upon pathogenic infection. Whereas A. butzleri and E. coli infected mice were clinically unaffected, respective colonic immune cell numbers increased in the former, but not in the latter, and more distinctly upon A. butzleri strain CCUG 30485 as compared to C1 strain infection. Both, A. butzleri and C. jejuni induced increased secretion of pro-inflammatory cytokines such as IFN-γ, TNF, IL-6 and MCP-1 in large, but also small intestines. Remarkably, even though viable bacteria did not translocate from the intestines to extra-intestinal compartments, systemic immune responses were induced in C. jejuni, but also A. butzleri infected mice as indicated by increased respective pro-inflammatory cytokine concentrations in serum samples at day 6 p.i.Conclusion / SignificanceA. butzleri induce less distinct pro-inflammatory sequelae as compared to C. jejuni, but more pronounced local and systemic immune responses than commensal E. coli in a strain-dependent manner. Hence, data point towards that A. butzleri is more than a commensal in vertebrate hosts.

Metagenomic analysis of bacterial community composition and antibiotic resistance genes in a wastewater treatment plant and its receiving surface water

The presence of pathogenic bacteria and the dissemination of antibiotic resistance genes (ARGs) may pose big risks to the rivers that receive the effluent from municipal wastewater treatment plants (WWTPs). In this study, we investigated the changes of bacterial community and ARGs along treatment processes of one WWTP, and examined the effects of the effluent discharge on the bacterial community and ARGs in the receiving river. Pyrosequencing was applied to reveal bacterial community composition including potential bacterial pathogen, and Illumina high-throughput sequencing was used for profiling ARGs. The results showed that the WWTP had good removal efficiency on potential pathogenic bacteria (especially Arcobacter butzleri) and ARGs. Moreover, the bacterial communities of downstream and upstream of the river showed no significant difference. However, the increase in the abundance of potential pathogens and ARGs at effluent outfall was observed, indicating that WWTP effluent might contribute to the dissemination of potential pathogenic bacteria and ARGs in the receiving river.