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Arcobacter butzleri is a foodborne pathogen associated with gastrointestinal disorders in humans. Its antibiotic resistance is well documented, and in vitro studies have shown its ability to colonise and invade human cell lines. Murine models are essential for integrating host immune responses and gut microbiota dynamics in infection studies. This study aimed to evaluate the pathogenicity and infectivity of A. butzleri strains using a murine model, focusing on invasion mechanisms and impact on intestinal microbiota. Fifteen Mus musculus C57BL/6J mice were orally infected with 8.5 Log CFU/ml of two strains. Faecal samples were collected before infection and over 14 days, while organs were analysed post-mortem. Infection was assessed using culture-dependent and culture-independent methods to study microbiota alterations. Molecular analyses confirmed the presence of A. butzleri in faecal samples until day 4. Beta-diversity analyses revealed significant differences in colonic microbiota between mice infected with the two strains. The duodenal microbiota was dominated by Paramuribaculum , Duncaniella , Dubosiella , and Muribaculum , whereas Akkermansia , Duncaniella , and Paramuribaculum were most prevalent in colonic and faecal samples. A. butzleri persisted under gastrointestinal conditions, a key feature for foodborne pathogens. Alterations in host microbiota were strongly associated with infection, emphasizing the critical role of microbial dynamics in A. butzleri pathogenesis.

Background Wild game meat has over the years gained popularity across the globe as it is considered a food source with high protein content, low fat content, and a balanced composition of fatty acids and minerals, which are requirements for a healthy diet. Despite this popularity, there is a concern over its safety as many species of wildlife are reservoirs of zoonotic diseases including those of bacterial origin, more so antibiotic-resistant bacteria. Methods This study aimed to describe the prevalence of antibiotic-resistant bacteria in mammalian wild game, following the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Results The overall pooled prevalence of antibiotic resistance was established at 59.8% while the prevalence of multidrug resistance (MDR) was 17.2%. Resistance was reported in 32 wild game species and the meta-analysis revealed the highest prevalence of antibiotic resistance in Yersinia spp. (95.5%; CI: 76.8 − 100%) followed by Enterococcus spp. (71%; CI: 44.1 − 92%), Salmonella spp. (69.9%; CI: 44.3 − 90.0%), Staphylococcus spp. (69.3%; CI: 40.3 − 92.3%), and Escherichia coli (39.5%; CI: 23.9 − 56.4%). Most notably, resistance to highest priority, critically important antimicrobials, was recorded in all genera of bacteria studied. Additionally, a significantly higher prevalence of antibiotic resistance was observed in studies conducted in remote settings than those in the vicinity of anthropogenic activities, pointing to extensive contamination of wild habitats. Conclusion This review shows the presence of antibiotic resistance and the carriage of antimicrobial resistance (AMR) genes by bacteria isolated from mammalian wild game species. This is a cause for concern if critical steps to prevent transmission to humans from meat and meat products are not applied in the wild game meat production chain. The extensive occurrence of antibiotic resistance in the wild calls for expansion and adaptation of future AMR surveillance plans to include areas with various anthropogenic pressures including in sylvatic habitats.

Escherichia albertii, a close relative of E. coli, is an emerging zoonotic foodborne pathogen associated with watery diarrhea mainly in children and immunocompromised individuals. E. albertii was initially classified as eae-positive Hafnia alvei, however, as more genetic and biochemical information became available it was reassigned to its current novel taxonomy. Its infections are common under conditions of poor hygiene with confirmed transmission via contaminated water and food, mainly poultry-based products. This pathogen has been isolated from various domestic and wild animals, with most isolates being derived from birds, implying that birds among other wild animals might act as its reservoir. Due to the absence of standardized isolation and identification protocols, E. albertii can be misidentified as other Enterobacteriaceae. Exploiting phenotypes such as its inability to ferment rhamnose and xylose and PCR assays targeting E. albertii-specific genes such as the cytolethal distending toxin and the DNA-binding transcriptional activator of cysteine biosynthesis encoding genes can be used to accurately identify this pathogen. Several gaps exist in our knowledge of E. albertii and need to be bridged. A deeper understanding of E. albertii epidemiology and physiology is required to allow the development of effective measures to control its transmission and infections. Overall, current data suggest that E. albertii might play a more significant role in global infectious diarrhea cases than previously assumed and is often overlooked or misidentified. Therefore, simple, and efficient diagnostic tools that cover E. albertii biodiversity are required for effective isolation and identification of this elusive agent of diarrhea.

Background/Objectives: Antimicrobial resistance (AMR) in wildlife is an emerging public health concern due to the risk of zoonotic transmission, especially through the food chain, yet data on free-ranging animals remain scarce. This study examined the presence and patterns of AMR among bacteria isolated from hunted wild boars in the Campania region of Italy. Methods: Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) was used to identify bacterial isolates from wild boar meat and carcass swabs to the species level, and the Kirby–Bauer disk diffusion test was applied to screen 205 isolates, spanning 20 bacterial genera, against a panel of clinically relevant antibiotics. Resistance metrics were analyzed at genus and antibiotic levels, and patterns were visualized using a hierarchically clustered heatmap. Results: Resistance was detected in 15 of the 20 genera, with full susceptibility observed in Acinetobacter, Arthrobacter, Glutamicibacter, Leclercia, and Rahnella. Overall, 67.3% (138/205) of the isolates showed resistance to at least one antibiotic, with 33.7% (69/205) classified as multidrug-resistant (MDR). Carbapenems retained the highest activity (≥95% susceptibility) among all genera tested, while amoxicillin/clavulanate (78.4%) and aztreonam (57.4%) exhibited the highest mean resistance. Among potential pathogens, Escherichia coli exhibited an extended-spectrum β-lactamase (ESBL)-like phenotype, with resistance to amoxicillin/clavulanate (67%), aztreonam (54%), and ceftazidime (47%) but preserved carbapenem susceptibility. Staphylococcus spp. showed pronounced resistance to linezolid (57%) and erythromycin (52%), whereas Pseudomonas isolates demonstrated elevated resistance to aztreonam and ceftazidime (57% each). Opportunistic pathogens such as Alcaligenes faecalis and Pantoea agglomerans showed peak resistance to ciprofloxacin and amoxicillin/clavulanate. Pathogens and opportunistic pathogens demonstrated higher mean resistance (>30%) than commensals (≤32%), but the difference in mean and median resistance levels was not statistically significant (Mann–Whitney’s U test, W = 4, p = 0.39). Conclusions: These findings highlight the widespread occurrence of AMR and MDR phenotypes, with clinically significant resistance patterns in wild-boar-associated bacteria, including non-pathogenic strains, highlighting their role in the amplification of AMR. Although the preservation of carbapenem susceptibility underscores their potential as last-line antibiotics, the high resistance to commonly used antibiotics raises concerns for zoonotic transmission. Surveillance of wildlife reservoirs therefore remains critical for integrated AMR control.

Twelve isolates of lactic acid bacteria (LAB) were obtained in the course of a bumble bee gut microbiota study and grouped into four matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry clusters. Comparative 16S rRNA gene sequence analysis revealed that cluster 1 isolates, represented by strain LMG 28288 T , are most closely related to Lactobacillus apis (97.0 % sequence similarity to that of L. apis LMG 26964 T ). Cluster 2 isolates represented by strain LMG 28290 T are most closely related to Weissella hellenica (99.6 % sequence similarity to that of W. hellenica LMG 15125 T ). The single cluster 3 and 4 isolates had identical 16S rRNA gene sequences which were 94.8 % similar to that of Leuconostoc mesenteroides subsp. mesenteroides LMG 6893 T , their nearest phylogenetic neighbour. A polyphasic taxonomic study additionally including comparative phe S sequence analysis, DNA–DNA hybridization experiments, DNA G+C content analysis, (GTG) 5 -PCR fingerprinting and a biochemical characterization, demonstrated that cluster 1 isolates represent a novel Lactobacillus species for which we propose the name Lactobacillus bombicola sp. nov. with LMG 28288 T (= DSM 28793 T ) as the type strain; and that cluster 2 isolates represent a novel Weissella species for which we propose the name Weissella bombi sp. nov. with LMG 28290 T (= DSM 28794 T ) as the type strain. Cluster 3 and 4 isolates, in contrast, represented a very distinct, novel taxon that could be distinguished from members of the genera Leuconostoc and Fructobacillus , its nearest phylogenetic neighbours, by its cellular morphology, non-fructophilic metabolism and DNA G+C content. We therefore classify both isolates into a novel species representing a novel LAB genus for which the name Convivina intestini gen. nov., sp. nov. is proposed with LMG 28291 T (= DSM 28795 T ) as the type strain.

Interventions from lairage to the chilling stage of the pig slaughter process are important to reduce microbial contamination of carcasses. The aim of this systematic review and meta-analysis was to assess the effectiveness of abattoir interventions in reducing aerobic colony count (ACC), Enterobacteriaceae, generic Escherichia coli, and Yersinia spp. on pig carcasses. The database searches spanned a 30 year period from 1990 to 2021. Following a structured, predefined protocol, 22 articles, which were judged as having a low risk of bias, were used for detailed data extraction and meta-analysis. The meta-analysis included data on lairage interventions for live pigs, standard processing procedures for pig carcasses, prechilling interventions, multiple carcass interventions, and carcass chilling. Risk ratios (RRs) for prevalence studies and mean log differences (MDs) for concentration outcomes were calculated using random effects models. The meta-analysis found that scalding under commercial abattoir conditions effectively reduced the prevalence of Enterobacteriaceae (RR: 0.05, 95% CI: 0.02 to 0.12, I2 = 87%) and ACC (MD: −2.84, 95% CI: −3.50 to −2.18, I2 = 99%) on pig carcasses. Similarly, significant reductions of these two groups of bacteria on carcasses were also found after singeing (RR: 0.25, 95% CI: 0.14 to 0.44, I2 = 90% and MD: −1.95, 95% CI: −2.40 to −1.50, I2 = 96%, respectively). Rectum sealing effectively reduces the prevalence of Y. enterocolitica on pig carcasses (RR: 0.60, 95% CI: 0.41 to 0.89, I2 = 0%). Under commercial abattoir conditions, hot water washing significantly reduced ACC (MD: −1.32, 95% CI: −1.93 to −0.71, I2 = 93%) and generic E. coli counts (MD: −1.23, 95% CI: −1.89 to −0.57, I2 = 61%) on pig carcasses. Conventional dry chilling reduced Enterobacteriaceae prevalence on pig carcasses (RR: 0.32, 95% CI: 0.21 to 0.48, I2 = 81%). Multiple carcass interventions significantly reduced Enterobacteriaceae prevalence (RR: 0.11, 95% CI: 0.05 to 0.23, I2 = 94%) and ACC on carcasses (MD: −2.85, 95% CI: −3.33 to −2.37, I2 = 97%). The results clearly show that standard processing procedures of scalding and singeing and the hazard-based intervention of hot water washing are effective in reducing indicator bacteria on pig carcasses. The prevalence of Y. enterocolitica on pig carcasses was effectively reduced by the standard procedure of rectum sealing; nevertheless, this was the only intervention for Yersinia investigated under commercial conditions. High heterogeneity among studies and trials investigating interventions and overall lack of large, controlled trials conducted under commercial conditions suggest that more in-depth research is needed.

The significance of Escherichia albertii as a foodborne pathogen is increasingly acknowledged, but the assessment of its occurrence and transmission remains challenging due to the lack of validation of selective isolation, detection, and identification methods. The aim of the present study was to examine its presence on various meat samples at the retail level in order to assess a potential foodborne transmission and its occurrence in clinical stool samples. First, the evaluation and selection of a selective enrichment broth and isolation medium, combined with an optimized identification by MALDI-TOF MS, as well as a suitable DNA extraction method and a PCR-based detection strategy were developed. After the evaluation of existing isolation strategies and the formulation of an adapted enrichment and isolation medium, 100% isolation specificity was not achieved. An identity confirmation of suspected colonies remains necessary. A total of 292 samples, including 45 beef fillet, 51 minced beef, 50 pork fillet, 30 minced pork, 30 chicken carcass, 51 chicken fillet, and 35 minced chicken samples were examined. Samples were all collected at the retail level, including supermarkets and local butcheries. Escherichia albertii was isolated from two chicken fillets (3.9%) and additionally detected in one minced chicken (4.5%) and two other chicken fillet (4.5%) samples by a PCR assay. All beef and pork samples tested negative for its presence, but transmission through these meat types cannot be excluded, as it potentially correlates with the level of fecal contamination that was significantly higher on poultry products. With other hygienic conditions and processing steps applied, the presence of E. albertii on food can therefore differ in other parts of the world. Escherichia albertii was present in 0.4% of the 2419 clinical stool samples examined. The future development of a chromogenic isolation medium, as well as further extensive epidemiologic approaches and a genomic comparison of human, food, and animal isolates, could enhance the assessment of the emerging pathogen status and its potential as a foodborne hazard.

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 LMG24486 T , 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.

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

Background Arcobacter spp. are a common contaminant of food and water, and some species, primarily A. butzleri and A. cryaerophilus , have been isolated increasingly from human diarrheal stool samples. Here, we describe the first Arcobacter multilocus sequence typing (MLST) method for A. butzleri , A. cryaerophilus , A. skirrowii, A. cibarius and A. thereius . Results A sample set of 374 arcobacters, including 275 A. butzleri , 72 A. cryaerophilus , 15 A. skirrowii and 8 A. cibarius isolates from a wide variety of geographic locations and sources, was typed in this study. Additionally, this sample set contained four strains representing a new Arcobacter species, A. thereius . The seven loci used in the four-species Arcobacter MLST method are the same as those employed previously in C. jejuni , C. coli , C. helveticus and C. fetus (i.e. aspA , atpA ( uncA ), glnA , gltA , glyA, pgm and tkt ). A large number of alleles were identified at each locus with the majority of isolates containing a unique sequence type. All Arcobacter isolates typed in this study contain two glyA genes, one linked to lysS ( glyA1 ) and the other linked to ada ( glyA2 ). glyA1 was incorporated into the Arcobacter MLST method while glyA2 was not because it did not increase substantially the level of discrimination. Conclusion No association of MLST alleles or sequence types with host or geographical source was observed with this sample set. Nevertheless, the large number of identified alleles and sequence types indicate that this MLST method will prove useful in both Arcobacter strain discrimination and in epidemiological studies of sporadic Arcobacter -related gastroenteritis. A new Arcobacter MLST database was created http://pubmlst.org/arcobacter/ ; allele and ST data generated in this study were deposited in this database and are available online.