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Antimicrobial resistance (AMR) is a public health risk that needs to be faced from a One Health perspective that includes humans, animals, and environmental health. The food production chain has been identified as a possible route of transmission of AMR bacteria to humans. The most critical phenomenon is related to Critically Important Antimicrobial (CIA) resistance. β-lactams antibiotics (cephalosporin of 3rd, 4th generation, carbapenem, monobactams, and penicillins), quinolones, aminoglycosides, polymyxin, and glycylcyclines were the CIAs chosen in this study. Samples derived from all the stages of the pork food production chain were collected, including pig feces, carcasses, and pork food products (fresh meat, fermented, and seasoned). Escherichia coli were isolated, and AMR and MDR profiles were evaluated. Enterobacterial Repetitive Intragenic Consensus (ERIC-PCR) was used to evaluate phylogenetic similarities. Data showed that 50% of phenotypical AMR observed in the entire pork food chain were related phylogenetically. The contamination of fresh meat, in half of the cases, was not directly related to contamination from feces or carcasses. Despite this, some similarities were found between feces and carcasses. In group analysis, phylogenetic similarities were detected in a 3/36 cluster (8.3%). Nevertheless, further studies are needed to improve consumer risk communication and access to clear and reliable information and health concerns on food labels. [ABSTRACT FROM AUTHOR]

Antimicrobial-resistant foodborne microorganisms may be transmitted from food producing animals to humans through the consumption of meat products. In this study, meat that was derived from farmed pigs and wild boars was analyzed and compared. Escherichia coli (E. coli) were isolated and tested phenotypically and genotypically for their resistance to quinolones, aminoglycosides and carbapenems. The co-presence of AMR-associated plasmid genes was also evaluated. A quinolone AMR phenotypic analysis showed 41.9% and 36.1% of resistant E. coli derived from pork and wild boars meat, respectively. A resistance to aminoglycosides was detected in the 6.6% of E. coli that was isolated from pork and in 1.8% of the wild boar meat isolates. No resistant profiles were detected for the carbapenems. The quinolone resistance genes were found in 58.3% of the phenotypically resistant pork E. coli and in 17.5% of the wild boar, thus showing low genotypic confirmation rates. The co-presence of the plasmid-related genes was observed only for the quinolones and aminoglycosides, but not for the carbapenems. Wild boar E. coli were the most capable to perform biofilm production when they were compared to pork E. coli. In conclusion, the contamination of pork and wild boar meat by AMR microorganisms could be a threat for consumers, especially if biofilm-producing strains colonize the surfaces and equipment that are used in the food industry. [ABSTRACT FROM AUTHOR]

The European Food Safety Authority and European Centre of Disease Prevention and Control antimicrobial resistance report published in 2021 shows increasing levels of antimicrobial resistance in Salmonella against antibiotics of choice for human salmonellosis (ß-lactams and fluoroquinolones). The aim of the study was to follow the evolution of resistance against some Critical Important Antimicrobials in Salmonella isolates from fresh pork collected in Emilia-Romagna region, northern Italy, over two decades. Emilia-Romagna region is characterized by production of well-known pork derived products, as Parma Ham. The samples were collected in three different periods, ranging from 2000 to 2003, 2012 to 2016 and 2018 to 2021. After serotyping, the isolates were phenotypically tested for resistance to three classes of antibiotics: ß-lactams, fluoroquinolones and polymyxins. End-point polymerase chain reaction (PCR) and PCRReal Time were used for genotypical analyses. The phenotypical resistance to ß-lactams and fluoroquinolones were clearly increasing when comparing the results obtained from isolates collected in the first period (16.7% and 16.7%, respectively) with those of the third period (29.7% and 32.4%, respectively). On the contrary, the resistance to colistin decreased from 33.3% to 5.4%. Genotypically, the 71.4% and 83.3% of the strains harboured ß-lactams and fluoroquinolones genes, respectively, while colistin resistance genes were not detected in the phenotypically resistant strains. [ABSTRACT FROM AUTHOR]

This study is focused on resistance to carbapenems and third-generation cephalosporins in Gram-negative microorganisms isolated from swine, whose transmission to humans via pork consumption cannot be excluded. In addition, the common carriage of carbapenem-resistant (CR) bacteria between humans and pigs was evaluated. Sampling involved 300 faecal samples collected from slaughtered pigs and 300 urine samples collected from 187 hospitalised patients in Parma Province (Italy). In swine, MIC testing confirmed resistance to meropenem for isolates of Pseudomonas aeruginosa and Pseudomonas oryzihabitans and resistance to cefotaxime and ceftazidime for Escherichia coli, Ewingella americana, Enterobacter agglomerans, and Citrobacter freundii. For Acinetobacter lwoffii, Aeromonas hydrofila, Burkolderia cepacia, Corynebacterium indologenes, Flavobacterium odoratum, and Stenotrophomonas maltophilia, no EUCAST MIC breakpoints were available. However, ESBL genes (blaCTXM-1, blaCTX-M-2, blaTEM-1, and blaSHV) and AmpC genes (blaCIT, blaACC, and blaEBC) were found in 38 and 16 isolates, respectively. P. aeruginosa was the only CR species shared by pigs (4/300 pigs; 1.3%) and patients (2/187; 1.1%). P. aeruginosa ST938 carrying blaPAO and blaOXA396 was detected in one pig as well as an 83-year-old patient. Although no direct epidemiological link was demonstrable, SNP calling and cgMLST showed a genetic relationship of the isolates (86 SNPs and 661 allele difference), thus suggesting possible circulation of CR bacteria between swine and humans. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) represents an increasing issue worldwide, spreading not only in humans and farmed animals but also in wildlife. One of the most relevant problems is represented by Extended-Spectrum Beta-Lactamases (ESβLs) producing Escherichia coli because they are the cause of important infections in human. Wild boars (Sus scrofa) as a source of ESβLs attracted attention due to their increasing density and their habits that lead them to be at the human-livestock-wildlife interface. The aim of this study was to increase the knowledge about the ESβLs E. coli strains carried by wild boars living in a particularly high-density area of Northern Italy. The analysis of 60 animals allowed to isolate 16 ESβL-producing E. coli strains (prevalence 23.3%), which were characterised from a phenotypical and molecular point of view. The overall analysis revealed that the 16 isolates were all not only ESβL producers but also multidrug resistant and carried different types of plasmid replicons. The genome analysis performed on a subset of isolates confirmed the heterogeneity observed with pulsed-field gel electrophoresis (PFGE) and highlighted the presence of two pandemic sequence types, ST131 and ST10, with different collections of virulence factors. The genomic context of ESβL genes further evidenced that all of them were surrounded by transposons and insertion sequences, suggesting the possibility to exchange AMR genes. Overall, this study shows the worrying dissemination of ESβL-producing E. coli in wild boars in Northern Italy, suggesting the role of these animals as a spreader of AMR and their inclusion in surveillance programmes, to shed light on the "One Health" complex interactions. [ABSTRACT FROM AUTHOR]

Hepatitis E virus (HEV) is a singlestrand RNA virus that causes an acute viral hepatitis in humans. Among its eight recognized genotypes, HEV-3 and HEV-4 are zoonotic, infecting humans, pigs and wild boars. Recently, HEV-3 has been also detected in red deer, which represents another reservoir of HEV. Consumption of raw pork products (mainly liver sausages), undercooked wild boar meat, raw wild boar liver and deer meat has been responsible for foodborne HEV human worldwide. From November 2018 to March 2019, liver samples collected from 97 wild boars hunted in Emilia-Romagna region (Northern Italy) were tested for HEV RNA. The hunting area included two territories for an extension of 33 km2, named A (about 13 km2,natural park, deciduous wood) and B (about 20 km2, cultivated fields in proximity of a river) areas. Distance between the two areas ranged between 8 to 10 km. A total of 73 wild boars were hunted in area A, and 24 in area B. HEV RNA was detected by Real-time RT- PCR in 23/73 liver samples of wild boars living in area A only (31.5% - 95% CI: 22.0- 42.8%). The HEV sequences (n=13) clustered within genotype 3. The majority of positives belonged to animals < 12 months (12/25; 48%), followed by subadults (13-24 months) (7/16; 43.8%) and adults (4/32; 12.5%). This difference was found to be statistically significant (p=0.0024). In absence of pig farms, the restriction of HEV-positive animals to a well-defined territory of 13 km2 (Boschi di Carrega Regional Park) could hypothetically be related to the presence of red deer (Cervus elaphus), which lived in area A at the beginning of the hunting season. Further studies are needed to confirm or deny our hypothesis. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance is an increasing global health problem and one of the major concerns for economic impacts worldwide. Recently, resistance against carbapenems (doripenem, ertapenem, imipenem, meropenem), which are critically important antimicrobials for human cares, poses a great risk all over the world. Carbapenemases are β-lactamases belonging to different Ambler classes (A, B, D) and encoded by both chromosomal and plasmidic genes. They hydrolyze a broad variety of β-lactams, including carbapenems, cephalosporins, penicillins and aztreonam. Despite several studies in human patients and hospital settings have been performed in European countries, the role of livestock animals, wild animals and the terrestrial and aquatic environment in the maintenance and transmission of carbapenemase- producing bacteria has been poorly investigated. The present review focuses on the carbapenemase-producing bacteria detected in pigs, cattle, poultry, fish, mollusks, wild birds and wild mammals in Europe as well as in non-European countries, investigating the genetic mechanisms for their transmission among food-producing animals and wildlife. To shed light on the important role of the environment in the maintenance and genetic exchange of resistance determinants between environmental and pathogenic bacteria, studies on aquatic sources (rivers, lakes, as well as wastewater treatment plants) are described. [ABSTRACT FROM AUTHOR]

Bovine tuberculosis (bTB) is a contagious chronic disease associated with progressive emaciation (starvation) and tubercles (granuloma) formation commonly caused by Mycobacterium bovis. In cattle, M. caprae may also be responsible for bTB. In EU, human tuberculosis due to M. bovis had a notification rate of 0.04 cases per 100,000 inhabitants in 2017, but data did not include M. caprae infections. From September 2018 to April 2019, bTB outbreaks were investigated in three neighbouring dairy cattle herds in Parma province, Northern Italy. Parma municipality belongs to an officially free of bovine tuberculosis (OTF) Italian region. Official testing on cattle herds, performed every three years as legally required, revealed no positive animals. Tubercular lesions were found during the post mortem (PM) examination of slaughtered cattle and M. caprae genotype SB0418/VNTR 4,3,5,3,4,5,2,2,4, 3,15,5 was isolated. This report confirms the crucial importance of PM veterinary inspection at slaughterhouse, despite the OTF status of cattle herds. [ABSTRACT FROM AUTHOR]

Wild boars (Sus scrofa) are increasing in several European countries, including Italy. In areas with intensive animal farming, like the Italian Emilia-Romagna region, they are likely to be exposed to antimicrobialresistant (AMR) bacteria of livestock origin. In 2017-2018, 108 mesenteric lymph nodes samples were collected from 108 wild boars hunted in Parma province, Emilia-Romagna region, to be tested for ESBL- and carbapenemase-producing Escherichia coli. One isolate (WB-21L) out of 108 (0.9%) was phenotypically confirmed as ESBLproducing E. coli. The strain WB-21L was tested by PCR for the genes blaSHV, blaCTX-M, blaTEM, blaAmpC, blaKPC, blaNDM, blaVIM, blaIMP, blaOXA-48, blaSPM, blaBIC, blaSIM, blaDIM, blaGIM, blaAIM, resulting positive for TEM β-lactamase. Resistance to ampicillin, amoxicillin/clavulanic acid, streptomycin, sulfasomidine, tetracycline and trimethoprim confirmed the multi-resistance nature of the strain WB-21L. Nine E.coli isolates showed resistance to meropenem by the Kirby Bauer test but none of them showed Meropenem MIC values indicative of resistance. In conclusion, the present study shows the presence of ESBL E. coli in wild boars and the possible risk of transfer to game meat handlers and consumers. Future studies are needed to better evaluate the sources of AMR bacteria in wildlife. [ABSTRACT FROM AUTHOR]

In order to evaluate Salmonella carrier status of cull dairy cattle at slaughter, 125 animals were randomly selected during the period February-May 2016. Dairy cows were reared in 89 farms located in two regions of Northern Italy (Lombardy and Emilia-Romagna regions), where bovine milk is primarily used for Parmigiano- Reggiano cheese and Grana Padano cheese production. Samples were collected by swabbing a 400-cm² area of the brisket hide and by rectoanal mucosal swabs. They were tested following the reference ISO 6579 method and the isolates were serotyped following the Kauffmann-White-Le Minor scheme and genotyped by XbaI PFGE. Salmonella was detected in 1.6% of the brisket hide samples (2/125) (95% CI: 0.4-5.6) and never found in faecal samples (95% CI: 0-3%). The positive cattle were reared in two farms located only in Emilia- Romagna region. The isolates were typed as S. Derby and S. Seftenberg. The comparison of the pulsed-field gel electrophoresis (PFGE) patterns of the bovine strains with all the PFGE patterns of the same serotypes responsible for human salmonellosis cases notified in Emilia-Romagna region in the years 2013-2015 did not find any correspondence. Therefore, the role of cull dairy cattle in transmitting Salmonella to humans seems to be less important than those of pigs and poultry in EU, but more data are needed for completing attribution source studies. [ABSTRACT FROM AUTHOR]

Ninety pig carcasses and twenty one food contact surfaces (FCSs) were tested for Salmonella in a slaughterhouse processing ca. 380 pigs/h between 2014-2015. Sampling was performed during seven sessions. Four carcass sites of 100 cm2 each (back, belly, jowl externally, and the diaphragmatic area internally) were swabbed after evisceration. Meat conveyors and dressing tables were tested swabbing areas of 200 to 400 cm2. After pre-enrichment in buffered peptone water, samples were tested by Salmonella MDS® assay and the presumptive positives were confirmed by the ISO 6579 method. Salmonella isolates were serotyped following the Kauffman-White-Le Minor scheme and genotyped by XbaI pulsed field gel electrophoresis. Salmonella was isolated from 16/90 [17.8%; confidence interval (CI) 95%=11.2-26.9] carcasses and 4/21 (19.0%; CI 95%= 7.7-40.0) FCSs. Four serovars were identified on carcasses. S. enterica 4,[5],12:i:-was the most prevalent (43.75%), followed by S. Rissen (31.25%), S. Derby (12.5%) and S. Bovismorbificans (12.5%). Two serovars were found on FCSs, namely S. Derby (75%) and S. Livingstone (25%). During one sampling session, a failure in carcass dehairing occurred and caused significantly higher prevalence of carcass contamination (60%) than in the remaining sessions. Moreover, in the same session, Salmonella prevalence was marginally significantly higher on FCSs than in the remaining sampling days, suggesting that dehairing affects contamination not only on carcasses, but also on the working surfaces. [ABSTRACT FROM AUTHOR]

Tonsils from 150 pigs slaughtered at 270days or older were tested for Yersinia enterocolitica with different cultural methods. Samples were collected in three different abattoirs of Northern Italy between April and November 2012 and were analysed by direct plating on cefsulodin–irgasan–novobiocin (CIN) agar and by enrichment procedures following the ISO 10273:2003 reference method. Twenty-three (15.3%) samples were positive: 22 tonsils (14.7%) were positive for human pathogenic Y. enterocolitica bio-serotype 4/O:3 and one tonsil (0.7%) for Y. enterocolitica bio-serotype 1A/7,8-8,8,19. Seventeen samples out of 23 (73.9%) were positive by direct plating method. Among the enrichment procedures, the best recovery rate (8 positives out of 23; 34.8%) was obtained by the two-day enrichment in peptone–sorbitol–bile (PSB) broth followed by plating on CIN agar plates. The two-day enrichment in PSB followed by potassium hydroxide (KOH) treatment before plating onto CIN agar gave 7 positives out of 23 (30.4%), decreasing to 3 positives (13.0%) without KOH treatment. The worst results were obtained by prolonged (five days) enrichment in PSB, with or without KOH treatment, followed by plating on CIN agar: 4.3% (1 out of 23) and 0.0% recovery rates, respectively. The mean concentration was 1.9×104 CFU/g, with a minimum of 1.0×102 CFU/g and a maximum of 5.8×104 CFU/g, thus demonstrating that tonsils may play an important role in contamination of pluck sets, carcasses, and slaughterhouse environment. Prevalence of virulence genes among the Y. enterocolitica 4/O:3 isolates was as follows: 12/22 (54.5%) for yadA, 21/22 (95.5%) for ail, 21/22 (95.5%) for inv and 22/22 (100%) for ystA. All Y. enterocolitica 4/O:3 isolates were sensitive to amoxicillin/clavulanic acid, ciprofloxacin and ceftazidime and resistant to ampicillin and cephalotin. High proportions of 4/O:3 isolates (95%) were sensitive to cefotaxime, gentamicin, kanamicin and nalidixic acid. High levels of resistance were observed to sulphonamide compounds (91%), streptomycin (64%) and chloramphenicol (55%). Multi-resistant isolates were very common; resistance to three or more antimicrobials was observed in 91% (20/22) of 4/O:3 isolates. High level of resistance to chloramphenicol was possibly due to coresistance to tiamphenicol, which was detected in 100% of the isolates. XbaI-PFGE detected four clusters among the 22 Y. enterocolitica 4/O:3 isolates. The most represented accounted for 77% (17/22) of the isolates, the second most common was found in 14% (3/22) of the isolates and the two other profiles were observed in single isolates. The comparison with a selection of human isolates supported the role of the pig as reservoir of 4/O:3 Y. enterocolitica. [ABSTRACT FROM AUTHOR]

The aim of the study was the comparative evaluation of an isothermal amplification and bioluminescence detection of DNA (IMBD) method and method ISO 6579:2002 for detection of Salmonella in retail meat products of unknown contamination status. A total of 200 meat samples were tested: 116 minced meat and meat preparations to be eaten cooked (52 chicken, 48 pork, and 16 beef samples) and 84 fresh meat samples (68 poultry and 16 pork). With one or both methods, 21 samples (10.5%) were positive for Salmonella enterica. Fifteen samples were positive with both methods (71.4% of all positive samples), two more samples (9.5%) were positive with the IMBD method only, and four samples (19.1%) were positive with the ISO method only. One ISO-positive sample was inhibited with the IMBD method. For the IMBD method, relative accuracy was 97.0% (95% confidence interval [CI], 93.6 to 98.9%), relative sensitivity was 78.9% (95% CI, 54.4 to 93.9%), and relative specificity was 98.9% (95% CI, 96.1 to 99.7%). Time to negative results was shorter with the IMBD method (20 to 24. h). Also, positive results were available in 20 to 24 h but should be confirmed using other methods (presumptive-positive results). Rapidity of response of the IMBD method gave us the opportunity to test the presumptive-positive samples by the most-probable-number (MPN) method, which was not performed for samples that were positive only with the ISO method because of likely microbial changes during the long storage period (5 to 7 days) at refrigeration temperature. Salmonella MPN values in naturally contaminated meat were low, at <0.3 to 2.1 MPN/g. [ABSTRACT FROM AUTHOR]

Torque teno sus virus (TTSuV) is a non-enveloped circular ssDNA virus which frequently infects swine and has been associated with hepatic, respiratory, and autoimmune disorders. TTSuV's pathogenic role is still uncertain, and clear data in the literature on virus reservoirs are lacking. The aims of this study were to investigate the presence of potentially zoonotic TTSuV in wild animals in Northern Italy and to evaluate their role as reservoirs. Liver samples were collected between 2016 and 2020 during four hunting seasons from wild boars (Sus scrofa), red deer (Cervus elaphus), roe deer (Capreolus capreolus), and chamois (Rupicapra rupicapra). Samples originated from areas in Northern Italy characterized by different traits, i.e., mountains and flatland with, respectively low and high farm density and anthropization. Viral identification was carried out by end-point PCR with specific primers for TTSuV1a and TTSuVk2a species. TTSuV prevalence in wild boars was higher in the mountains than in the flatland (prevalence of 6.2% and 2.3%, respectively). In wild ruminants only TTSuVk2a was detected (with a prevalence of 9.4%). Our findings shed light on the occurrence and distribution of TTSuV in some wild animal species, investigating their possible role as reservoirs. [ABSTRACT FROM AUTHOR]

Verocytotoxin-producing Escherichia coli (VTEC) has emerged as a foodborne pathogen that can cause severe and potentially fatal illnesses, such as hemorrhagic colitis or the hemolytic uremic syndrome. In this study, 182 cattle at slaughter (119 dairy cows and 63 feedlot cattle) were randomly selected and tested for the presence of VTEC serogroups 026, O103, O111, O145, and O157 in their cecal content and lymphatic tissue (tonsils or mesenteric lymph nodes). A total of 364 samples were evaluated with an immunomagnetic separation technique followed by slide agglutination. Presumptive VTEC 026, O103, O111, O145, and O157 isolates were tested by Vero cell assay for verocytotoxin production and by multiplex PCR assay for the detection of vtx1, vtx2, eae, and E-hlyA genes. VTEC O157 was detected in 6 (3.3%) of 182 animals, and VTEC 026 was detected in 1 (0.5%) of 182 animals. No VTEC O103, VTEC O111, or VTEC O145 isolates were found in cattle feces, but one VTEC O91:H- vtx2+, eae-, E-hlyA- strain nonspecifically cross-reacted with the VTEC O103 type. The prevalence of VTEC O157 in the lymphatic tissue of cattle was 1.1% in both tonsils (1 of 93 samples) and mesenteric lymph nodes (1 of 89 samples). Lymphatic tissue contamination was observed only in VTEC O157 intestinal carriers; two (33.3%) of six fecal carriers were simultaneously VTEC O157 lymphatic carriers. This finding suggests that VTEC O157 contamination of meat does not necessarily come from feces or the environment. No other VTEC serogroups were detected in the lymphatic tissue of slaughtered cattle. [ABSTRACT FROM AUTHOR]

Mammalian orthoreoviruses (MRVs) are emerging infectious agents that may affect wild animals. MRVs are usually associated with asymptomatic or mild respiratory and enteric infections. However, severe clinical manifestations have been occasionally reported in human and animal hosts. An insight into their circulation is essential to minimize the risk of diffusion to farmed animals and possibly to humans. The aim of this study was to investigate the presence of likely zoonotic MRVs in wild ungulates. Liver samples were collected from wild boar, red deer, roe deer, and chamois. Samples originated from two areas (Sondrio and Parma provinces) in Northern Italy with different environmental characteristics. MRV detection was carried out by PCR; confirmation by sequencing and typing for MRV type 3, which has been frequently associated with disease in pigs, were carried out for positive samples. MRV prevalence was as high as 45.3% in wild boars and 40.6% in red deer in the Sondrio area, with lower prevalence in the Parma area (15.4% in wild boars). Our findings shed light on MRV occurrence and distribution in some wild species and posed the issue of their possible role as reservoir. [ABSTRACT FROM AUTHOR]

Wild boars ( Sus scrofa ) are increasing in several European countries, including Italy. In areas with intensive animal farming, like the Italian Emilia-Romagna region, they are likely to be exposed to antimicrobialresistant (AMR) bacteria of livestock origin. In 2017-2018, 108 mesenteric lymph nodes samples were collected from 108 wild boars hunted in Parma province, Emilia-Romagna region, to be tested for ESBL- and carbapenemase-producing Escherichia coli . One isolate (WB-21L) out of 108 (0.9%) was phenotypically confirmed as ESBLproducing E. coli . The strain WB-21L was tested by PCR for the genes bla SHV , bla CTX-M , bla TEM , bla AmpC , bla KPC , bla NDM , bla VIM , bla IMP , bla OXA-48 , bla SPM , bla BIC , bla SIM , bla DIM , bla GIM , bla AIM , resulting positive for TEM β- lactamase. Resistance to ampicillin, amoxicillin/clavulanic acid, streptomycin, sulfasomidine, tetracycline and trimethoprim confirmed the multi-resistance nature of the strain WB-21L. Nine E.coli isolates showed resistance to meropenem by the Kirby Bauer test but none of them showed Meropenem MIC values indicative of resistance. In conclusion, the present study shows the presence of ESBL E. coli in wild boars and the possible risk of transfer to game meat handlers and consumers. Future studies are needed to better evaluate the sources of AMR bacteria in wildlife., Competing Interests: Conflict of interests: the authors declare no potential conflict of interests.

During 2014-2015, 300 pig carcasses before chilling and 85 food contact surfaces (FCSs) at cutting lines were tested for Salmonella in three slaughterhouses (namely A, B, and C) of northern Italy. In slaughterhouses A and B, four carcass sites of 100 cm 2 each (from both the exterior and interior side) were swabbed with a single sponge. In abattoir C, four 100 cm 2 sites of the exterior and the interior sides were swabbed with two independent sponges. The population average prevalence of Salmonella-positive carcasses (which takes into account the structure of the study design, with multiple samples collected in a single day) in slaughterhouses A and B was 12.3%, while in slaughterhouse C it was 11.2%. Presence of Salmonella on exterior and interior sides of carcasses showed a low level of concordance (only 3/12 of the contaminated carcasses were positive on both sides). No significant difference was found for FCSs contamination in the three slaughterhouses, with a population average prevalence of Salmonella-positive FCSs of 19.9%. In addition, we found that the clustering due to the day of sampling account for more than 36% and 60% of the overall prevalence variation on carcasses and FCSs, respectively. Eight serovars were identified, with Salmonella Derby as the most common type. The counting of Salmonella on carcasses showed large variability. It was low (<0.0075 most probable number [MPN]/cm 2 ) in 46.6% of the carcasses and as high as 2.7 MPN/cm 2 in 4.7%. Specifically, we found that counts on carcasses fit with "heavy tailed" distributions (lognormal and Weibull with a small shape parameter), suggesting not negligible probability of episodes of high Salmonella contamination. The mean values of contamination obtained with the two distributions ranged from 0.235 to 0.435 MPN/cm 2 .

Salmonella Brandenburg ranked 16 th among the serovars responsible for human infections in EU in 2015 and it was found to be associated with swine. In Emilia- Romagna and Lombardy regions of northern Italy, S. Brandenburg was isolated from mesenteric lymph nodes, fecal matter, carcasses and conveyor belts at pig slaughterhouses in 2014 and 2015. In the same area, S. Brandenburg was detected in pork salami in 2015. In the present study, 12 isolates of S. Brandenburg recovered from the pork food-chain were typed by Xba I PFGE and their three profiles were compared to all human S . Brandenburg isolates processed by the Surveillance System of Emilia- Romagna region from 2012 to 2017 (105 isolates). The most frequent pulsotype of porcine origin (6/12) was the second most frequent in humans (16/105). Of the other two pulsotypes of porcine origine (3/12 each), one was the most frequent in humans (41/105), the other was undetected among human isolates., Competing Interests: Conflict of interest: the authors declare no potential conflict of interest.

Finishing pigs carrying Salmonella enterica are believed to be the main source of carcass contamination at the beginning of slaughtering. The aim of this study was to assess the S. enterica carrier status of finishing pigs at herd level by sampling pooled faeces on farm and mesenteric lymph nodes at slaughter in the North East of Italy. Environmental faecal samples belonging to 30 batches of pigs were collected on farm. At slaughter, mesenteric lymph nodes were collected from five randomly selected pigs per batch. S. enterica was isolated from 16 lymph nodes out of 150 (10.6%) and from seven out of 30 (23.3%) faecal samples. Four batches (13.3%) were positive to S. enterica both in lymph nodes and in faeces. The number of batches positive to S. enterica either in lymph nodes or in faeces was 13 out of 30 (43.3%). The most prevalent serovars from lymph nodes were S . Derby (25.0%) and S . Typhimurium monophasic variant 1, 4,[5],12:i:- (18.6%), which were also isolated from faecal material (14.3 and 42.8% respectively). Contaminated faecal material or lymph nodes could be a primary source of carcass contamination at slaughter during evisceration. S. enterica contamination is widespread on pig farms and carrier pigs pass undetected the inspection visits at slaughter, entering the food chain. Therefore, in order to control S. enterica in pigs, the need to quantify possible risk factors at slaughter and develop effective management strategies on farm is of paramount importance to ensure food safety., Competing Interests: the authors declare no potential conflict of interests.