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In a previous study characterizing Campylobacter strains deficient in selenium metabolism, 50 strains were found to be similar to, but distinct from, the selenonegative species Campylobacter lanienae. Initial characterization based on multilocus sequence typing and the phylogeny of a set of 20 core genes determined that these strains form three putative taxa within the selenonegative cluster. A polyphasic study was undertaken here to further clarify their taxonomic position within the genus. The 50 selenonegative strains underwent phylogenetic analyses based on the sequences of the 16S rRNA gene and an expanded set of 330 core genes. Standard phenotypic testing was also performed. All strains were microaerobic and anaerobic, Gram-negative, spiral or curved cells with some displaying coccoid morphologies. Strains were motile, oxidase, catalase, and alkaline phosphatase positive, urease negative, and reduced nitrate. Strains within each clade had unique phenotypic profiles that distinguished them from other members of the genus. Core genome phylogeny clearly placed the 50 strains into three clades. Pairwise average nucleotide identity and digital DNA-DNA hybridization values were all below the recommended cut-offs for species delineation with respect to C. lanienae and other related Campylobacter species. The data presented here clearly show that these strains represent three novel species within the genus, for which the names Campylobacter devanensis sp. nov. (type strain RM3662T=LMG 33097T=NCTC 15074T), Campylobacter porcelli sp. nov. (type strain RM6137T=LMG 33098T=CCUG 77054T=NCTC 15075T) and Campylobacter vicugnae sp. nov. (type strain RM12175T=LMG 33099T=CCUG 77055T=NCTC 15076T) are proposed.
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Técnicas de Tipagem Bacteriana , Campylobacter , DNA Bacteriano , Tipagem de Sequências Multilocus , Hibridização de Ácido Nucleico , Filogenia , RNA Ribossômico 16S , Análise de Sequência de DNA , RNA Ribossômico 16S/genética , Campylobacter/genética , Campylobacter/classificação , Campylobacter/isolamento & purificação , Animais , DNA Bacteriano/genética , Suínos , Ruminantes/microbiologiaRESUMO
Campylobacter jejuni and Campylobacter coli are well known for their natural competence, i.e., their capacity for the uptake of naked DNA with subsequent transformation. This study identifies non-transformable C. jejuni and C. coli strains from domestic animals and employs genomic analysis to investigate the strain genotypes and their associated genetic mechanisms. The results reveal genetic associations leading to a non-transformable state, including functional DNase genes from bacteriophages and mutations within the cts-encoded DNA-uptake system, which impact the initial steps of the DNA uptake during natural transformation. Interestingly, all 38 tested C. jejuni ST-50 strains from the United States exhibit a high prevalence of non-transformability, and the strains harbor a variety of these genetic markers. This research emphasizes the role of these genetic markers in hindering the transfer of antimicrobial resistance (AMR) determinants, providing valuable insights into the genetic diversity of Campylobacter. As ST-50 is a major clone of C. jejuni globally, we additionally determined the prevalence of the genetic markers for non-transformability among C. jejuni ST-50 from different regions of the world, revealing distinct patterns of evolution and a strong selective pressure on the loss of competence in ST-50 strains, particularly in the agricultural environment in the United States. Our findings contribute to a comprehensive understanding of genetic exchange mechanisms within Campylobacter strains, and their implications for antimicrobial resistance dissemination and evolutionary pathways within specific lineages.
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We tested the hypothesis that Campylobacter isolated from chicken ceca and river water in an overlapping geographic area would share genetic information. Isolates of C. jejuni from chicken ceca were collected from a commercial slaughter plant and isolates of C. jejuni were also collected from rivers and creeks in the same watershed. Isolates were subjected to whole-genome sequencing and the data were used for core genome multilocus sequence typing (cgMLST). Cluster analysis showed that there were four distinct subpopulations, two from chickens and two from water. Calculation of fixation statistic (Fst) showed that all four subpopulations were significantly distinct. Greater than 90% of the loci were differentiated by subpopulation. Only two genes showed clear differentiation of both chicken subpopulations from both water subpopulations. Sequence fragments of the CJIE4 bacteriophage family were found frequently in the main chicken subpopulation and the water outgroup subpopulation but were sparsely found in the main water population and not at all in the chicken outgroup. CRISPR spacers that targeted the phage sequences were common in the main water subpopulation, only once in the main chicken subpopulation, and not at all in the chicken or water outgroups. Restriction enzyme genes also showed a biased distribution. These data suggest that there is little transfer of C. jejuni genetic material between chickens and nearby river water. Campylobacter differentiation according to these two sources does not show clear evidence of evolutionary selection; the differentiation is probably due to geospatial isolation, genetic drift, and the action of CRISPRs and restriction enzymes. IMPORTANCE Campylobacter jejuni causes gastroenteritis in humans, and chickens and environmental water are leading sources of infection. We tested the hypothesis that Campylobacter isolated from chicken ceca and river water in an overlapping geographic area would share genetic information. Isolates of Campylobacter were collected from water and chicken sources in the same watershed and their genomes were sequenced and analyzed. Four distinct subpopulations were found. There was no evidence of sharing genetic material between the subpopulations. Phage profiles, CRISPR profiles and restriction systems differed by subpopulation.
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Young turkeys are vulnerable to undifferentiated gastrointestinal distress, including "irritable and crabby syndrome" (ICS), which compromises flock performance and is typically treated with a combination of penicillin and gentamicin (P/G). However, the effects of ICS and P/G treatment on Campylobacter remain poorly understood. We investigated the impact of ICS and P/G treatment on Campylobacter levels and diversity in four flocks from three turkey farms. Cecum and jejunum samples were analyzed weekly from day of hatch to week 4-5. All four flocks became colonized with multidrug resistant (MDR) Campylobacter jejuni and C. coli by week 2-3, and two developed ICS. ICS and P/G treatment did not significantly impact total Campylobacter levels or strain genotypes but impacted species and antimicrobial resistance (AMR) profiles. One flock was raised under antibiotic-free (ABF) conditions while another flock at the same farm was raised conventionally. The ABF flock did not develop ICS while its counterpart did. However, Campylobacter strains, AMR profiles and sequence types were generally shared between these two flocks. Our findings suggest that ICS and P/G treatment impacted Campylobacter population dynamics in commercial young turkey flocks, and that ABF flocks may become readily colonized by MDR strains from non-ABF flocks at the same farm.
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Campylobacter is a leading foodborne pathogen, and poultry are a major vehicle for infection. Houseflies play important roles in colonization of broiler flocks with Campylobacter but comparable information for turkey farms is limited. Here, we investigated houseflies as potential vectors for Campylobacter in 28 commercial turkey flocks. We characterized species, genotypes, and the antimicrobial resistance (AMR) profiles of Campylobacter from turkey feces and houseflies in the same turkey house. Of the 28 flocks, 25 yielded Campylobacter from turkey droppings and houseflies, with an average of 6.25 and 3.11 Campylobacter log CFU/g feces and log CFU/fly, respectively. Three flocks were negative for Campylobacter both in turkey feces and in houseflies. Both C. coli and C. jejuni were detected in turkey feces and houseflies, with C. coli more likely to be recovered from houseflies than feces. Determination of Campylobacter species, genotypes, and AMR profiles revealed up to six different strains in houseflies from a single house, including multidrug-resistant strains. For the predominant strain types, presence in houseflies was predictive of presence in feces, and vice versa. These findings suggest that houseflies may serve as vehicles for dissemination of Campylobacter, including multidrug-resistant strains, within a turkey house, and potentially between different turkey houses and farms in the same region.
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Campylobacter jejuni and Campylobacter coli are leading zoonotic foodborne pathogens, and the drugs of choice for human campylobacteriosis are macrolides (e.g., erythromycin) and fluoroquinolones. C. jejuni and C. coli are naturally competent for transformation via naked DNA uptake, but potential differences in transformation frequency (TF) for different antimicrobial resistance (AMR) markers remain poorly understood. We determined TFs for resistance to different antibiotics using as recipient a derivative of C. jejuni NCTC 11168 (strain SN:CM) with donor DNA from multidrug-resistant C. jejuni or C. coli. TF for nalidixic acid resistance ranked significantly highest (~1.4 × 10-3), followed by resistance to streptomycin and gentamicin. Tetracycline resistance via chromosomal tet(O) was less commonly transferred (~7.6 × 10-7), while transformation to erythromycin resistance was rare (≤4.7 × 10-8). We also determined TFs with the contemporary poultry-derived strains C. jejuni FSIS 11810577 and C. coli FSIS 1710488 as recipients. TFs to nalidixic acid and streptomycin resistance remained the highest (~7 × 10-4). However, TF for gentamicin resistance was remarkably low in certain recipient-donor combinations, while average TF for erythromycin resistance was noticeably higher (~3 × 10-6) than with SN:CM. Findings from this experimental model provide insights into factors that may impact transformation-mediated transfer of AMR leading to AMR dissemination in the agricultural ecosystem.
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Campylobacter jejuni is a significant cause of human gastroenteritis worldwide, and all strains express an N-glycan that is added to at least 80 different proteins. We characterized 98 C. jejuni isolates from infants from 7 low- and middle-income countries and identified 4 isolates unreactive with our N-glycan-specific antiserum that was raised against the C. jejuni heptasaccharide composed of GalNAc-GalNAc-GalNAc(Glc)-GalNAc-GalNAc-diNAcBac. Mass spectrometric analyses indicated these isolates express a hexasaccharide lacking the glucose branch. Although all 4 strains encode the PglI glucosyltransferase (GlcTF), one aspartate in the DXDD motif was missing, an alteration also present in â¼4% of all available PglI sequences. Deleting this residue from an active PglI resulted in a nonfunctional GlcTF when the protein glycosylation system was reconstituted in E. coli, while replacement with Glu/Ala was not deleterious. Molecular modeling proposed a mechanism for how the DXDD residues and the structure/length beyond the motif influence activity. Mouse vaccination with an E. coli strain expressing the full-length heptasaccharide produced N-glycan-specific antibodies and a corresponding reduction in Campylobacter colonization and weight loss following challenge. However, the antibodies did not recognize the hexasaccharide and were unable to opsonize C. jejuni isolates lacking glucose, suggesting this should be considered when designing N-glycan-based vaccines to prevent campylobacteriosis.
Assuntos
Campylobacter jejuni/metabolismo , Glucose/metabolismo , Polissacarídeos/metabolismo , Sequência de Aminoácidos , Animais , Ácido Aspártico/química , Configuração de Carboidratos , Sequência de Carboidratos , Ensaio de Imunoadsorção Enzimática , Escherichia coli/metabolismo , Glicosilação , Soros Imunes , Camundongos , Fagocitose , Polissacarídeos/química , Alinhamento de SequênciaRESUMO
This paper re-examines the taxonomic positions of recently described Poseidonibacter (P. parvum and P. antarcticus), Aliarcobacter ('Al. vitoriensis'), Halarcobacter ('H. arenosus') and Arcobacter (A. caeni, A. lacus) species, and other species proposed to represent novel genera highly related to the genus Arcobacter. Phylogenomic and several overall genome relatedness indices (OGRIs) were applied to a total of 118 representative genomes for this purpose. Phylogenomic analyses demonstrated the Arcobacter clade to be distinct from other Epsilonproteobacteria, clearly defined and containing closely related species. Aliarcobacter butzleri and Malaciobacter pacificus did not cluster with other members of these proposed genera, indicating incoherence of these genera. Every OGRI measure applied indicated a high level of relatedness among all Arcobacter clade species, including the recently described taxa studied here, and substantially lower between type species representatives for other Epsilonproteobacteria. Where published guidelines were available, OGRI values for Arcobacter clade species were either unsupportive of division into other genera or were at the lowest boundary range (for average amino acid identity). We propose that Aliarcobacter, Halarcobacter, Malaciobacter, Pseudarcobacter, Poseidonibacter and Arcobacter sensu stricto be considered members of a single genus, Arcobacter, and subsequently transfer P. parvum, P. antarcticus, 'Al. vitoriensis' and 'H. arenosus' to Arcobacter as Arcobacter parvum comb. nov., Arcobacter antarcticus comb. nov., Arcobacter vitoriensis comb. nov. and Arcobacter arenosus comb. nov.
Assuntos
Arcobacter , Filogenia , Arcobacter/classificaçãoRESUMO
An increasing number of Arcobacter species (including several regarded as emerging human foodborne pathogens) have been isolated from shellfish, an important food commodity. A method to distinguish these species and render viable isolates for further analysis would benefit epidemiological and ecological studies. We describe a method based on Elastic Light Scatter analysis (ELSA) for the detection and discrimination of eleven shellfish-associated Arcobacter species. Although substantive differences in the growth rates of some taxa were seen, ELSA was able to differentiate all the species studied, apart from some strains of A. butzleri and A. cryaerophilus, which were nonetheless distinguished from all other species examined. ELSA appears to be a promising new approach for the detection and identification of Arcobacter species in shellfish and may also be applicable for studies in other foods and matrices.
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During a sampling of wild red foxes (Vulpes vulpes) for the detection of Epsilonproteobacteria, 14 strains were isolated from the caecal contents of 14 epidemiologically-unrelated animals. A genus-specific PCR indicated that the isolates belonged to the genus Campylobacter. Based on the results of a species-specific PCR, the isolates were initially identified as C. upsaliensis. However, multi-locus sequence typing (MLST) revealed that the isolates were significantly different from the C. upsaliensis present in the MLST database. A polyphasic study, including conventional biochemical and tolerance characteristics, morphology by transmission electron microscopy (TEM), MALDI-TOF analysis, and genetic comparisons based on partial 16S rDNA and atpA gene sequences, was undertaken. Finally, the complete genome sequence of the type strain 251/13T and the draft genome sequences of the other isolates were determined. Average nucleotide identity, average amino acid identity and in silico DNA-DNA hybridization analyses confirmed that the isolates represent a novel taxon for which the name Campylobacter vulpis sp. nov. is proposed, with isolate 251/13T (=CCUG 70587Tâ¯=â¯LMG 30110T) as the type strain. In order to allow a rapid discrimination of C. vulpis from the closely-related C. upsaliensis, a specific PCR test was designed, based on atpA gene sequences.
Assuntos
Campylobacter , Raposas , Filogenia , Animais , Técnicas de Tipagem Bacteriana , Composição de Bases , Campylobacter/classificação , Campylobacter/isolamento & purificação , DNA Bacteriano/genética , Raposas/microbiologia , Tipagem de Sequências Multilocus , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Campylobacter jejuni is the leading bacterial cause of gastroenteritis worldwide with excessive incidence in low-and middle-income countries (LMIC). During a survey for C. jejuni from putative animal hosts in a town in the Peruvian Amazon, we were able to isolate and whole genome sequence two C. jejuni strains from domesticated guinea pigs (Cavia porcellus). The C. jejuni isolated from guinea pigs had a novel multilocus sequence type that shared some alleles with other C. jejuni collected from guinea pigs. Average nucleotide identity and phylogenetic analysis with a collection of C. jejuni subsp. jejuni and C. jejuni subsp. doylei suggest that the guinea pig isolates are distinct. Genomic comparisons demonstrated gene gain and loss that could be associated with guinea pig host specialization related to guinea pig diet, anatomy, and physiology including the deletion of genes involved with selenium metabolism, including genes encoding the selenocysteine insertion machinery and selenocysteine-containing proteins.
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Infecções por Campylobacter , Campylobacter jejuni , Animais , Infecções por Campylobacter/veterinária , Campylobacter jejuni/genética , Genoma Bacteriano , Genômica , Cobaias , Tipagem de Sequências Multilocus , FilogeniaRESUMO
Although at least two genetically distinct groups, or genomospecies, have been well documented for Campylobacter concisus, no phenotype has yet been identified for their differentiation and thus formal description as separate species. C. concisus has been isolated from a variety of sites in the human body, including saliva and stool samples from both healthy and diarrhoeic individuals. We evaluated the ability of a range of whole genome-based tools to distinguish between the two C. concisus genomospecies (GS) using a collection of 190 C. concisus genomes. Nine genomes from related Campylobacter species were included in some analyses to provide context. Analyses incorporating sequence analysis of multiple ribosomal genes generated similar levels of C. concisus GS discrimination as genome-wide comparisons. The C. concisus genomes formed two groups; GS1 represented by ATCC 33237T and GS2 by CCUG 19995. The two C. concisus GS were separated from the nine genomes of related species. GS1 and GS2 also differed in G+C content with medians of 37.56% and 39.51%, respectively. The groups are consistent with previously established GS and are supported by DNA reassociation results. Average Nucleotide Identity using MUMmer (ANIm) and Genome BLAST Distance Phylogeny generated in silico DNA-DNA hybridisation (isDDH) (against ATCC 33237T and CCUG 19995), plus G+C content provides cluster-independent GS discrimination suitable for routine use. Pan-genomic analysis identified genes specific to GS1 and GS2. WGS data and genomic species identification methods support the existence of two GS within C. concisus. These data provide genome-level metrics for strain identification to genomospecies level.
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Campylobacter , Genoma Bacteriano , Filogenia , Composição de Bases , Campylobacter/classificação , Campylobacter/genética , Genômica , Hibridização de Ácido NucleicoRESUMO
Bacterial resistance to ceftiofur raises health concerns due to ceftiofur's extensive veterinary usage and structural similarity with the human antibiotic ceftriaxone. Ceftiofur crystalline-free acid (CCFA) and ceftiofur hydrochloride (CHCL) are ceftiofur types used therapeutically in cattle, but their potential impacts on Campylobacter prevalence and antimicrobial resistance remain unclear. In this study two groups of steers were each treated with CCFA or CHCL. In vivo active drug concentrations were measured and fecal samples were analyzed for Campylobacter for up to 42 days post-treatment. Following administration, the colonic concentration of ceftiofur initially increased then dropped to pre-treatment levels by day 8. The estimated prevalence of Campylobacter spp. was significantly (p = 0.0009) higher during the first week after CCFA treatment than after CHCL treatment (81.3% vs. 45.2%). Campylobacter jejuni predominated overall, with other Campylobacter spp. mainly identified in the first week after CCFA treatment. No treatment impacts were noted on ceftiofur minimum inhibitory concentration (MIC) for C. jejuni (10-20 µg/mL). More C. jejuni genotypes were detected in CCFA-treated than CHCL-treated steers. These findings suggest that ceftiofur did not significantly impact Campylobacter prevalence or ceftiofur MIC. However, CHCL may be preferable due to the lower likelihood of temporary increases in Campylobacter prevalence.
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Here, we present the complete genome sequence of a Campylobacter strain isolated in the Netherlands from a patient with gastroenteritis. The strain showed >98% sequence identity to the novel Campylobacter species sequence recently recovered from metagenomic data, isolated from breastfed infants with diarrheal disease, and named "Candidatus Campylobacter infans."
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Campylobacter pinnipediorum was described recently for isolates recovered from pinnipeds. The novel species was further split into 2 subspecies based on host and geography, with C. pinnipediorum subsp. pinnipediorum recovered from otariid seals in California (USA) and C. pinnipediorum subsp. caledonicus recovered from phocid seals in Scotland. We report details of the infections of 7 pinnipeds from which C. pinnipediorum was isolated: C. pinnipediorum subsp. caledonicus was isolated from 2 harbour seals Phoca vitulina and a single grey seal Halichoerus grypus, and C. pinnipediorum subsp. pinnipediorum was isolated from California sea lions Zalophus californianus. Six of the isolates were recovered from samples collected at post-mortem investigation. In 2 of the Scottish seals and in 3 of the California seals, C. pinnipediorum was the sole bacterial isolate recovered from abscesses present and suggests they may have resulted from conspecific or intraspecific bite wounds.
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Campylobacter , Caniformia , Phoca , Focas Verdadeiras , Abscesso/veterinária , Animais , EscóciaRESUMO
The proposal to restructure the genus Arcobacter into six distinct genera was critically examined using: comparative analyses of up to 80 Epsilonproteobacterial genome sequences (including 26 arcobacters); phylogenetic analyses of three housekeeping genes and also 342 core genes; and phenotypic criteria. Genome sequences were analysed with tools to calculate Percentage of Conserved Proteins, Average Amino-acid Identity, BLAST-based Average Nucleotide Identity, in silico DNA-DNA hybridisation values, genome-wide Average Nucleotide Identity, Alignment Fractions and G+C percentages. Genome analyses revealed the genus Arcobacter sensu lato to be relatively homogenous, and phylogenetic analyses clearly distinguished the group from other Epsilonproteobacteria. Genomic distinction of the genera proposed by Pérez-Cataluña et al. [2018] was not supported by any of the measures used and a subsequent risk of strain misidentification clearly identified. Similarly, phenotypic analyses supported the delineation of Arcobacter sensu lato but did not justify the position of the proposed novel genera. The present polyphasic taxonomic study strongly supports the continuance of the classification of "aerotolerant campylobacters" as Arcobacter and refutes the proposed genus-level subdivision of Pérez-Cataluña et al. [2018].
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Arcobacter/classificação , Epsilonproteobacteria/classificação , Arcobacter/genética , Arcobacter/crescimento & desenvolvimento , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Técnicas de Tipagem Bacteriana , Sequência de Bases , DNA Bacteriano/genética , Epsilonproteobacteria/genética , Epsilonproteobacteria/crescimento & desenvolvimento , Genes Bacterianos , Genes de RNAr , Genoma Bacteriano , Genômica , Hibridização de Ácido Nucleico , Fenótipo , Filogenia , Proteoma , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
In September 2018, Hurricane Florence caused extreme flooding in eastern North Carolina, USA, a region highly dense in concentrated animal production, especially swine and poultry. In this study, floodwater samples (n = 96) were collected as promptly post-hurricane as possible and for up to approximately 30 days and selectively enriched for Campylobacter using Bolton broth enrichment and isolation on modified charcoal cefoperazone deoxycholate agar (mCCDA) microaerobically at 42°C. Only one sample yielded Campylobacter, which was found to be Campylobacter jejuni with the novel sequence type 2866 (ST-2866). However, the methods employed to isolate Campylobacter readily yielded Arcobacter from 73.5% of the floodwater samples. The Arcobacter isolates failed to grow on Mueller-Hinton agar at 25, 30, 37, or 42°C microaerobically or aerobically but could be readily subcultured on mCCDA at 42°C microaerobically. Multilocus sequence typing of 112 isolates indicated that all were Arcobacter butzleri The majority (85.7%) of the isolates exhibited novel sequence types (STs), with 66 novel STs identified. Several STs, including certain novel ones, were detected in diverse waterbody types (channel, isolated ephemeral pools, floodplain) and from multiple watersheds, suggesting the potential for regionally dominant strains. The genotypes were clearly partitioned into two major clades, one with high representation of human and ruminant isolates and another with an abundance of swine and poultry isolates. Surveillance of environmental waters and food animal production systems in this animal agriculture-dense region is needed to assess potential regional prevalence and temporal stability of the observed A. butzleri strains as well as their potential association with specific types of food animal production.IMPORTANCE Climate change and associated extreme weather events can have massive impacts on the prevalence of microbial pathogens in floodwaters. However, limited data are available on foodborne zoonotic pathogens such as Campylobacter or Arcobacter in hurricane-associated floodwaters in rural regions with intensive animal production. With a high density of intensive animal production as well as pronounced vulnerability to hurricanes, eastern North Carolina presents unique opportunities in this regard. Our findings revealed widespread incidence of the emerging zoonotic pathogen Arcobacter butzleri in floodwaters from Hurricane Florence. We encountered high and largely unexplored diversity while also noting the potential for regionally abundant and persistent clones. We noted pronounced partitioning of the floodwater genotypes into two source-associated clades. The data will contribute to elucidating the poorly understood ecology of this emerging pathogen and highlight the importance of surveillance of floodwaters associated with hurricanes and other extreme weather events for Arcobacter and other zoonotic pathogens.
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Arcobacter/isolamento & purificação , Tempestades Ciclônicas , Genótipo , Rios/microbiologia , Arcobacter/genética , Campylobacter jejuni/isolamento & purificação , Inundações , Tipagem de Sequências Multilocus , North CarolinaRESUMO
Arcobacter anaerophilus was originally described as the first obligate anaerobe in this genus by Sasi Jyothsna et al. 2013. The complete genome sequence of the type strain of this species was determined and analysed. Genes characteristic for organisms capable of aerobic growth were identified, and the ability of the organism to grow under microaerobic and aerobic conditions was confirmed in two independent laboratories. The description of A. anaerophilus is thus emended and the wider ramifications of these findings are discussed.
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Arcobacter/classificação , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Genes Bacterianos , Genômica , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
Arcobacter species are recovered from a wide variety of sources, including animals, food, and both fresh and marine waters. Several Arcobacter species have also been recovered from human clinical samples and are thus associated tentatively with food- and water-borne human illnesses. Genome sequencing of the poultry isolate Arcobacter cibarius H743 and the Arcobacter acticola, Arcobacter pacificus, and Arcobacter porcinus type strains identified a large number and variety of insertion sequences. This study presents an analysis of these A. acticola, A. cibarius, A. pacificus, and A. porcinus IS elements. The four genomes sequenced here contain 276 complete and degenerate IS elements, representing 13 of the current 29 prokaryotic IS element families. Expansion of the analysis to include 15 other previously sequenced Arcobacter spp. added 73 complete and degenerate IS elements. Several of these IS elements were identified in two or more Arcobacter species, suggesting movement by horizontal gene transfer between the arcobacters. These IS elements are putatively associated with intragenomic deletions and inversions, and tentative movement of antimicrobial resistance genes. The A. cibarius strain H743 megaplasmid contains multiple IS elements common to the chromosome and, unusually, a complete ribosomal RNA locus, indicating that larger scale genomic rearrangements, potentially resulting from IS element-mediated megaplasmid cointegration and resolution may be occurring within A. cibarius and possibly other arcobacters. The presence of such a large and varied suite of mobile elements could have profound effects on Arcobacter biology and evolution.