Multicentre evaluation of a selective isolation protocol for detection of mcr-positive E. coli and Salmonella spp. in food-producing animals and meat.

This study was conducted to evaluate the performance of a screening protocol to detect and isolate mcr-positive Escherichia coli and Salmonella spp. from animal caecal content and meat samples. We used a multicentre approach involving 12 laboratories from nine European countries. All participants applied the same methodology combining a multiplex PCR performed on DNA extracted from a pre-enrichment step, followed by a selective culture step on three commercially available chromogenic agar plates. The test panel was composed of two negative samples and four samples artificially contaminated with E. coli and Salmonella spp. respectively harbouring mcr-1 or mcr-3 and mcr-4 or mcr-5 genes. PCR screening resulted in a specificity of 100% and a sensitivity of 83%. Sensitivity of each agar medium to detect mcr-positive colistin-resistant E. coli or Salmonella spp. strains was 86% for CHROMID® Colistin R, 75% for CHROMagarTM COL-APSE and 70% for COLISTIGRAM. This combined method was effective to detect and isolate most of the E. coli or Salmonella spp. strains harbouring different mcr genes from food-producing animals and food products and might thus be used as a harmonized protocol for the screening of mcr genes in food-producing animals and food products in Europe.

Novel IncFII plasmid harbouring blaNDM-4 in a carbapenem-resistant Escherichia coli of pig origin, Italy.

OBJECTIVES: To the best of our knowledge, we describe the first evidence in Europe of an MDR, blaNDM-4-positive Escherichia coli isolated from a food-producing animal, harboured by a novel IncFII plasmid of which we report the complete sequence. METHODS: One blaNDM-4-positive E. coli isolated in 2019 from the caecal contents of a fattening pig in Italy was in-depth characterized by combined bioinformatic analysis of Oxford Nanopore long reads and Illumina short reads, for in silico typing, determination of the blaNDM-4 genetic context and full reconstruction of the blaNDM-4-carrying plasmid. RESULTS: The isolate belonged to ST641 and to the genoserotype O108:H23 and tested positive for different virulence genes and plasmid replicons. The MDR phenotype of resistance to all ß-lactams, carbapenems, sulfamethoxazole and trimethoprim was mediated by blaTEM-1B, blaNDM-4, sul1/sul3 and dfrA12, respectively. The blaNDM-4 gene was harboured by a novel 53 043 bp IncFII plasmid (pMOL412_FII) composed of four main genetic regions, including an MDR region (MRR-NDM-4) of 16 kb carrying blaNDM-4 and several antimicrobial resistance genes located in a class 1 integron. pMOL412_FII was closely related to another ∼90.3 kb plasmid (pM109_FII) harbouring blaNDM-4 in an E. coli isolated from a human patient in Myanmar. CONCLUSIONS: To the best of our knowledge, we have identified for the first time in Europe an NDM-producing Enterobacterales in livestock and resolved the complete sequence of the novel pMOL412_FII plasmid harbouring blaNDM-4 in an MRR. A global One Health approach, comparing genomic data from different sources and geographical areas, may help to trace back and control possible plasmid-borne carbapenemase gene transmission between animals and humans and along the food chain at international level.

Systemic tuberculosis by MYCOBACTERIUM BOVIS in a free-ranging MARSICAN brown bear (URSUS ARCTOS MARSICANUS): a Case report.

BACKGROUND: Mycobacterium bovis is known to have a wide host range and has been isolated from numerous free-ranging wildlife species, carnivores included. In bears, M. bovis has been previously reported only from a culture of pooled lymph nodes of a black bear (Ursus americanus) in the absence of lesions. The aims of this study were to describe gross and microscopic pathological findings of M. bovis tuberculosis in a deceased Marsican brown bear (Ursus arctos marsicanus). CASE PRESENTATION: In March 2014, an adult female Marsican brown bear was found in the Abruzzo, Lazio and Molise National Park (Italy) showing severe non-specific clinical signs. The animal died soon after its discovery and the carcass was submitted to post-mortem examination to identify the cause of death. The bear was diagnosed with a severe Mycobacterium bovis infection, with both pathological and microbiological aspects suggesting ongoing generalization. A presumptive diagnosis of mycobacterial infection was initially made based on gross findings. Histopathology showed the presence of acid-fast bacilli in all sampled tissues along with poorly organized granulomatous lesions. Slow-growing Mycobacterium sp. was isolated from multiple organs (intestine, mesenteric lymph nodes, liver, spleen, lung and kidneys). The PCR and sequencing algorithm identified the Mycobacterium sp. isolate as M. bovis. Spoligotyping demonstrated that the M. bovis isolate belonged to spoligotype SB0120. CONCLUSIONS: This is the first report of lethal M. bovis tuberculosis infection in a free-ranging brown bear. This pathogen could have serious adverse effects in an endangered relic population such as the Marsican brown bear. Stricter application of health regulations in force, surveillance of M. bovis infections in wild ungulates and carnivore scavengers, along with dismissal of supplementary feeding points intended for cattle or wildlife, are warranted to control the presence of bovine tuberculosis in wild and domestic animals in protected areas.

Multiplex PCR for detection of plasmid-mediated colistin resistance determinants, mcr-1, mcr-2, mcr-3, mcr-4 and mcr-5 for surveillance purposes.

Background and aimPlasmid-mediated colistin resistance mechanisms have been identified worldwide in the past years. A multiplex polymerase chain reaction (PCR) protocol for detection of all currently known transferable colistin resistance genes (mcr-1 to mcr-5, and variants) in Enterobacteriaceae was developed for surveillance or research purposes. Methods: We designed four new primer pairs to amplify mcr-1, mcr-2, mcr-3 and mcr-4 gene products and used the originally described primers for mcr-5 to obtain a stepwise separation of ca 200 bp between amplicons. The primer pairs and amplification conditions allow for single or multiple detection of all currently described mcr genes and their variants present in Enterobacteriaceae. The protocol was validated testing 49 European Escherichia coli and Salmonella isolates of animal origin. Results: Multiplex PCR results in bovine and porcine isolates from Spain, Germany, France and Italy showed full concordance with whole genome sequence data. The method was able to detect mcr-1, mcr-3 and mcr-4 as singletons or in different combinations as they were present in the test isolates. One new mcr-4 variant, mcr-4.3, was also identified. Conclusions: This method allows rapid identification of mcr-positive bacteria and overcomes the challenges of phenotypic detection of colistin resistance. The multiplex PCR should be particularly interesting in settings or laboratories with limited resources for performing genetic analysis as it provides information on the mechanism of colistin resistance without requiring genome sequencing.

Evidence of a Prototheca Zopfii Genotype 2 Disseminated Infection in a Dog with Cutaneous Lesions.

Protothecosis is a disease caused by saprophyte aerobic unicellular algae belonging to the genus Prototheca. In dogs, it mainly occurs as a disseminated form, with initial clinical manifestations often referable to the gastrointestinal tract, followed by typical ocular and neurological signs. So far, Prototheca zopfii genotype 2 infection has been reported in severe forms of disseminated protothecosis, while in dogs has never been associated with cutaneous forms. In this study, we describe a case of Prototheca zopfii genotype 2 infection in a dog characterized by nodular and ulcerative dermatitis and with evidence of dissemination. In December 2015, a 5-year-old unneutered male English Setter dog was presented with a 4-month history of footpads ulcerations and multifocal nodular lesions (3-5 cm diameter) on both front limbs. Cytological examination of the aspirated fluid collected from all nodules revealed the presence of sporangic forms compatible with Prototheca spp. organisms. Suspected Prototheca spp. colonies were isolated from the aspirated fluid and identified as Prototheca zopfii genotype 2 by molecular methods. Few days after the visit, the patient developed serious neurological and ocular signs, and the owners elected humane euthanasia. To the authors' knowledge, this case could represent the first report of a disseminated Prototheca zopfii genotype 2 infection associated with cutaneous lesions in a dog. This study underlines the importance of considering Prototheca zopfii genotype 2 infection in the differential etiological diagnosis of nodular and ulcerative dermatitis in dogs.

Evidence for Human Adaptation and Foodborne Transmission of Livestock-Associated Methicillin-Resistant Staphylococcus aureus.

We investigated the evolution and epidemiology of a novel livestock-associated methicillin-resistant Staphylococcus aureus strain, which colonizes and infects urban-dwelling Danes even without a Danish animal reservoir. Genetic evidence suggests both poultry and human adaptation, with poultry meat implicated as a probable source.

A Livestock-Associated, Multidrug-Resistant, Methicillin-Resistant Staphylococcus aureus Clonal Complex 97 Lineage Spreading in Dairy Cattle and Pigs in Italy.

Pandemic methicillin-resistant Staphylococcus aureus (MRSA) clonal complex 97 (CC97) lineages originated from livestock-to-human host jumps. In recent years, CC97 has become one of the major MRSA lineages detected in Italian farmed animals. The aim of this study was to characterize and analyze differences in MRSA and methicillin-susceptible S. aureus (MSSA) mainly of swine and bovine origins. Forty-seven CC97 isolates, 35 MRSA isolates, and 6 MSSA isolates from different Italian pig and cattle holdings; 5 pig MRSA isolates from Germany; and 1 human MSSA isolate from Spain were characterized by macrorestriction pulsed-field gel electrophoresis (PFGE) analysis, multilocus sequence typing (MLST), spa typing, staphylococcal cassette chromosome mec (SCCmec) typing, and antimicrobial resistance pattern analysis. Virulence and resistance genes were investigated by PCR and microarray analysis. Most of the isolates were of SCCmec type V (SCCmec V), except for two German MRSA isolates (SCCmec III). Five main clusters were identified by PFGE, with the German isolates (clusters I and II) showing 60.5% similarity with the Italian isolates, most of which (68.1%) grouped into cluster V. All CC97 isolates were Panton-Valentine leukocidin (PVL) negative, and a few (n = 7) tested positive for sak or scn. All MRSA isolates were multidrug resistant (MDR), and the main features were erm(B)- or erm(C)-mediated (n = 18) macrolide-lincosamide-streptogramin B resistance, vga(A)-mediated (n = 37) pleuromutilin resistance, fluoroquinolone resistance (n = 33), tet(K) in 32/37 tet(M)-positive isolates, and blaZ in almost all MRSA isolates. Few host-associated differences were detected among CC97 MRSA isolates: their extensive MDR nature in both pigs and dairy cattle may be a consequence of a spillback from pigs of a MRSA lineage that originated in cattle as MSSA and needs further investigation. Measures should be implemented at the farm level to prevent spillover to humans in intensive farming areas.

Beta-hemolytic, multi-lancefield antigen-agglutinating Enterococcus durans from a pregnant woman, mimicking Streptococcus agalactiae.

A beta-hemolytic Lancefield antigen A-, B-, C-, D-, F-, and G-positive Enterococcus durans strain was cultivated from the rectovaginal swab of a pregnant woman who underwent antenatal screening for Streptococcus agalactiae. The isolate raised concern as to what extent similar strains are misrecognized and lead to false diagnosis of group B streptococci.

Cetacean strandings in Italy: an unusual mortality event along the Tyrrhenian Sea coast in 2013.

An unusual mortality event involving cetaceans, mainly striped dolphins Stenella coeruleoalba (Meyen, 1833), occurred along the Tyrrhenian Sea coast of Italy during the first 3 mo of 2013. Based on post-mortem analyses carried out according to body condition on 66 dolphins (54% of stranded animals), several hypotheses to explain the causes of this mortality event were proposed. Although no definitive conclusions can be drawn, dolphin morbillivirus was deemed the most likely cause, although other infectious agents (including Photobacterium damselae damselae and herpesvirus) or environmental factors may also have contributed to this recent mortality event.

Evidence of structural rearrangements in ESBL-positive pESI(like) megaplasmids of S.Infantis.

The increasing prevalence of pESI(like)-positive, multidrug-resistant (MDR) S. Infantis in Europe is a cause of major concern. As previously demonstrated, the pESI(like) megaplasmid is not only a carrier of antimicrobial resistant (AMR) genes (at least tet, dfr, and sul genes), but also harbours several virulence and fitness genes, and toxin/antitoxin systems that enhance its persistence in the S. Infantis host. In this study, five prototype pESI(like) plasmids, of either CTX-M-1 or CTX-M-65 ESBL-producing strains, were long-read sequenced using Oxford Nanopore Technology (ONT), and their complete sequences were resolved. Comparison of the structure and gene content of the five sequenced plasmids, and further comparison with previously published pESI(like) sequences, indicated that although the sequence of such pESI(like) 'mosaic' plasmids remains almost identical, their structures appear different and composed of regions inserted or transposed after different events. The results obtained in this study are essential to better understand the plasticity and the evolution of the pESI(like) megaplasmid, and therefore to better address risk management options and policy decisions to fight against AMR and MDR in Salmonella and other food-borne pathogens. Graphical representation of the pESI-like plasmid complete sequence (ID 12037823/11). Block colours indicate the function of the genes: red: repB gene; pink: class I integrons (IntI); yellow; mobile elements; blue: resistance genes; green: toxin/anti-toxin systems; grey: mer operon; light green: genes involve in conjugation.

Genomics Insight into cfr-Mediated Linezolid-Resistant LA-MRSA in Italian Pig Holdings.

The cfr genes encode for a 23S rRNA methyltransferase, conferring a multiresistance phenotype to phenicol, lincosamide, oxazolidinone, pleuromutilin, and streptogramin A antibiotics. These genes have been described in staphylococci, including methicillin-resistant Staphylococcus aureus (MRSA). In this study, we retrospectively performed an in-depth genomic characterisation of three cfr-positive, multidrug-resistant (MDR) livestock-associated (LA) MRSA clonal complexes (CCs) 1 and 398 detected in different Italian pig holdings (2008-2011) during population studies on Italian livestock (2008-2014). We used a combined Illumina and Oxford Nanopore Technologies (ONT) whole genome sequencing (WGS) approach on two isolates (the 2008 CC1 and the 2010 CC398 isolates, but not the 2011 CC1 isolate). Interestingly, the three isolates presented different cfr variants, with only one displaying a linezolid-resistant phenotype. In isolate 2008 CC1, the cfr gene was identified within a Tn558 composite transposon-like structure flanked by IS elements located on a novel 44,826 bp plasmid. This represents the first report of CC1 LA-MRSA harbouring the cfr gene in its functional variant. Differently, cfr was chromosomally located in isolate 2010 CC398. Our findings have significant public health implications, confirm the need for the continuous genomic surveillance of cfr-positive zoonotic LA-MRSA, and backdate cfr presence in LA-MRSA from Italian pigs to at least 2008.

Genomics insights into a Mycobacterium pinnipedii isolate causing tuberculosis in a captive South American sea lion (Otaria flavescens) from Italy.

Tuberculosis (TB) affects humans and other animals, and it is caused by bacteria within the Mycobacterium tuberculosis complex (MTBC). In this study, we report the characterisation of Mycobacterium pinnipedii that caused a TB case in a sea lion (Otaria flavescens) kept in an Italian zoo. The animal died due to severe, progressive disorders involving the respiratory and gastro-enteric systems and the skin. At necropsy, typical gross lesions referable to a TB generalised form were found. In particular, nodular granulomatous lesions were detected in the lungs and several lymph nodes, and colonies referable to Mycobacterium spp. were isolated from lung, mesenteric, and mediastinal lymph nodes. The isolate was identified by PCR as a MTBC, had a spoligotype SB 1480 ("seal lineage"), and was characterised and characterised by whole-genome sequencing analysis confirming that the MTBC involved was M. pinnipedii. The analysis of the resistome and virulome indicated the presence of macrolide and aminoglycoside resistance genes intrinsic in M. tuberculosis [erm-37 and aac(2')-Ic] and confirmed the presence of the region of difference 1 (RD1), harbouring the esxA and esxB virulence genes, differently from its closest taxon, M. microti. As for other MTCB members, M. pinnipedii infection can spill over into non-pinniped mammalian species; therefore, zoological gardens, veterinary practitioners, and public health officers should be aware of the hazard posed by tuberculosis from marine mammals. Since the isolate under study, as well as all available genomes of M. pinnipedii investigated in this study retains almost all the M. tuberculosis virulence genes, it could indeed cause infection, lesions, and disease in other animal species, including humans.

The hazard of carbapenemase (OXA-181)-producing Escherichia coli spreading in pig and veal calf holdings in Italy in the genomics era: Risk of spill over and spill back between humans and animals.

Carbapenemase-producing Enterobacterales (CPE) are considered a major public health issue. In the frame of the EU Harmonized AMR Monitoring program conducted in Italy in 2021, 21 epidemiological units of fattening pigs (6.98%; 95% CI 4.37-10.47%; 21/301) and four epidemiological units of bovines <12 months (1.29%; 95% CI 0.35-3.27%, 4/310) resulted positive to OXA-48-like-producing E. coli (n = 24 OXA-181, n = 1 OXA-48). Whole Genome Sequencing (WGS) for in-depth characterization, genomics and cluster analysis of OXA-181-(and one OXA-48) producing E. coli isolated, was performed. Tracing-back activities at: (a) the fattening holding of origin of one positive slaughter batch, (b) the breeding holding, and (c) one epidemiologically related dairy cattle holding, allowed detection of OXA-48-like-producing E. coli in different units and comparison of further human isolates from fecal samples of farm workers. The OXA-181-producing isolates were multidrug resistant (MDR), belonged to different Sequence Types (STs), harbored the IncX and IncF plasmid replicons and multiple virulence genes. Bioinformatics analysis of combined Oxford Nanopore Technologies (ONT) long reads and Illumina short reads identified bla OXA-181 as part of a transposon in IncX1, IncX3, and IncFII fully resolved plasmids from 16 selected E. coli, mostly belonging to ST5229, isolated during the survey at slaughter and tracing-back activities. Although human source could be the most likely cause for the introduction of the bla OXA-181-carrying IncX1 plasmid in the breeding holding, concerns arise from carbapenemase OXA-48-like-producing E. coli spreading in 2021 in Italian fattening pigs and, to a lesser extent, in veal calf holdings.

A European multicenter evaluation study to investigate the performance on commercially available selective agar plates for the detection of carbapenemase producing Enterobacteriaceae.

The European Food Safety Authority (EFSA) advised to prioritize monitoring carbapenemase producing Enterobacteriaceae (CPE) in food producing animals. Therefore, this study evaluated the performance of different commercially available selective agars for the detection of CPE using spiked pig caecal and turkey meat samples and the proposed EFSA cultivation protocol. Eleven laboratories from nine countries received eight samples (four caecal and four meat samples). For each matrix, three samples contained approximately 100 CFU/g CPE, and one sample lacked CPE. After overnight enrichment in buffered peptone water, broths were spread upon Brilliance™ CRE Agar (1), CHROMID® CARBA (2), CHROMagar™ mSuperCARBA™ (3), Chromatic™ CRE (4), CHROMID® OXA-48 (5) and Chromatic™ OXA-48 (6). From plates with suspected growth, one to three colonies were selected for species identification, confirmation of carbapenem resistance and detection of carbapenemase encoding genes, by methods available at participating laboratories. Of the eleven participating laboratories, seven reported species identification, susceptibility tests and genotyping on isolates from all selective agar plates. Agars 2, 4 and 5 performed best, with 100% sensitivity. For agar 3, a sensitivity of 96% was recorded, while agar 1 and 6 performed with 75% and 43% sensitivity, respectively. More background flora was noticed for turkey meat samples than pig caecal samples. Based on this limited set of samples, most commercially available agars performed adequately. The results indicate, however, that OXA-48-like and non-OXA-48-like producers perform very differently, and one should consider which CPE strains are of interest to culture when choosing agar type.

Molecular characterization of spa type t127, sequence type 1 methicillin-resistant Staphylococcus aureus from pigs.

OBJECTIVES: The aim of this study was to provide molecular characterization of methicillin-resistant Staphylococcus aureus (MRSA) spa type t127, sequence type (ST) 1 isolates, detected in a European baseline survey in holdings of breeding pigs, to determine phenotypic and genotypic drug resistance and to compare the results with those obtained from a collection of t127, ST1 MRSA and methicillin-susceptible S. aureus (MSSA) clinical isolates. METHODS: Twenty-four t127, ST1 MRSA from dust sampled in different breeding holdings in Italy, Spain and Cyprus were studied, along with 2 t127, ST1 MRSA from fattening pigs and 11 human t127, ST1 MRSA and MSSA. Genotyping was performed using multilocus sequence typing (MLST), spa typing and PFGE. SCCmec elements were characterized by multiplex-PCR and resistance and pathogenicity genes by PCR and microarray. RESULTS: PFGE patterns separated a porcine cluster (PC) from a human cluster (HC), with 75% similarity. The PC carried SCCmec cassette type V, while all isolates of the HC carried SCCmec cassette type IVa. Kanamycin resistance mediated by aadD, fluoroquinolone and erm(A)-mediated macrolide resistance and the absence of the sakA gene were features of the PC only. All isolates of both clusters were positive for LukE-LukD and LuF-LukS-HlgA leukotoxin genes and one human MSSA harboured Panton-Valentine leucocidin genes. CONCLUSIONS: Despite differences in the host-specific genetic features, the possibility of PC transmission to humans cannot be excluded. MRSA spa type t127, ST1 from pigs possesses several virulence and resistance genes towards major classes of antimicrobials and may represent a serious therapeutic challenge in case of invasive infections in humans.

International collaborative study on the occurrence of plasmid-mediated quinolone resistance in Salmonella enterica and Escherichia coli isolated from animals, humans, food and the environment in 13 European countries.

OBJECTIVES: This study was initiated to collect retrospective information on the occurrence of plasmid-mediated quinolone resistance (PMQR) in Salmonella enterica and Escherichia coli isolates in Europe and to identify the responsible genes. METHODS: Databases of national reference laboratories containing MIC values for Salmonella and E. coli isolated between 1994 and 2009 in animals, humans, food and the environment from 13 European countries were screened for isolates exhibiting a defined quinolone resistance phenotype, i.e. reduced susceptibility to fluoroquinolones and nalidixic acid. PCR and sequence analysis were performed to identify the responsible PMQR genes. RESULTS: Screening of databases of 13 European countries resulted in a selection of 1215 Salmonella and 333 E. coli isolates. PMQR genes were identified in 59% of the Salmonella isolates and 15% of the E. coli isolates selected. In Salmonella, qnrS1 (n = 125) and variants of qnrB (n = 138) were frequently identified, whereas qnrA1 (n = 3) and aac(6')-1b-cr (n = 3) were rarely found. qnrD was detected in 22 Salmonella isolates obtained from humans and animals. In E. coli, qnrS1 was identified in 19 isolates and qnrB19 was found in one isolate. No qnrC or qepA genes were detected in either Salmonella or E. coli. CONCLUSIONS: This study shows the occurrence and dissemination of PMQR genes in Salmonella and E. coli in Europe with a defined quinolone resistance phenotype. We also report the first detection of qnrD in Salmonella collected in Europe.

Emergence of IncHI2 Plasmids With Mobilized Colistin Resistance (mcr)-9 Gene in ESBL-Producing, Multidrug-Resistant Salmonella Typhimurium and Its Monophasic Variant ST34 From Food-Producing Animals in Italy.

A collection of 177 genomes of Salmonella Typhimurium and its monophasic variant isolated in 2014-2019 from Italian poultry/livestock (n = 165) and foodstuff (n = 12), previously screened for antimicrobial susceptibility and assigned to ST34 and single-locus variants, were studied in-depth to check the presence of the novel mcr-9 gene and to investigate their genetic relatedness by whole genome sequencing (WGS). The study of accessory resistance genes revealed the presence of mcr-9.1 in 11 ST34 isolates, displaying elevated colistin minimum inhibitory concentration values up to 2 mg/L and also a multidrug-resistant (MDR) profile toward up to seven antimicrobial classes. Five of them were also extended-spectrum beta-lactamases producers (bla SHV - 12 type), mediated by the corresponding antimicrobial resistance (AMR) accessory genes. All mcr-9-positive isolates harbored IncHI2-ST1 plasmids. From the results of the Mash analysis performed on all 177 genomes, the 11 mcr-9-positive isolates fell together in the same subcluster and were all closely related. This subcluster included also two mcr-9-negative isolates, and other eight mcr-9-negative ST34 isolates were present within the same parental branch. All the 21 isolates within this branch presented an IncHI2/2A plasmid and a similar MDR gene pattern. In three representative mcr-9-positive isolates, mcr-9 was demonstrated to be located on different IncHI2/IncHI2A large-size (∼277-297 kb) plasmids, using a combined Illumina-Oxford Nanopore WGS approach. These plasmids were also compared by BLAST analysis with publicly available IncHI2 plasmid sequences harboring mcr-9. In our plasmids, mcr-9 was located in a ∼30-kb region lacking different genetic elements of the typical core structure of mcr-9 cassettes. In this region were also identified different genes involved in heavy metal metabolism. Our results underline how genomics and WGS-based surveillance are increasingly indispensable to achieve better insights into the genetic environment and features of plasmid-mediated AMR, as in the case of such IncHI2 plasmids harboring other MDR genes beside mcr-9, that can be transferred horizontally also to other major Salmonella serovars spreading along the food chain.

Carbapenemase IncF-borne blaNDM-5 gene in the E. coli ST167 high-risk clone from canine clinical infection, Italy.

The blaNDM-5-producing E. coli Sequence Type (ST)167 high-risk clone is emerging worldwide in human clinical cases, while its presence in companion animals is sporadic and has never been described in Italy. Using a combined Oxford Nanopore (ONT) long-reads and Illumina short-reads sequencing approach, an E. coli ST167 isolated from a hospitalized dog, was in-depth characterized by WGS and the plasmid containing blaNDM-5 was fully reconstructed. The complete sequence of the pMOL008 mosaic plasmid (F36:F31:A4:B1; pMOL008) harbouring blaNDM-5, was resolved and characterized. Moreover, a (pro)phage and IncFII, containing blaCMY-2 and ermB, and IncI2 plasmid types were also identified. pMOL008 was almost identical to blaNDM-5-containing plasmids from E. coli ST167 isolated from Italian human clinical cases and from a Swiss dog and colonized humans. blaNDM-5 was located in a class 1 integron together with aadA2, aac(3)-IIa, mph(A), sul1, tet(A) and dfrA12. The risk of spill-over and spill-back transmission of carbapenem-resistance genes, related plasmids and strains between humans and dogs, represents a Public Health threat and highlights the importance of the One Health approach for the AMR surveillance.

Livestock-Associated Methicillin-Resistant Staphylococcus aureus and Related Risk Factors in Holdings of Veal Calves in Northwest Italy.

Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) have emerged worldwide as zoonotic pathogens. Data on LA-MRSA in veal calf production in Italy are lacking; the aim of this survey was to fill current knowledge gaps in its prevalence and characteristics. Between February 2012 and January 2013 nasal swabs were taken from 1650 three- to six-month-old veal calves on 55 farms in Piedmont (northwest Italy), including gathering-related epidemiological data. S. aureus were screened for methicillin resistance by phenotypic and molecular (mecA gene detection) methods. MRSA were further genotyped by multilocus sequence typing. About 30% of the herds tested positive for MRSA: three different clonal complexes (CC398, CC97, and CC1) and staphylococcal cassette chromosome mec types (IVa, IVb, and V) were detected. Multilevel logistic regression model indicated poor cleaning, importation from Austria, and animal age as risk factors and coagulase-negative staphylococci colonization as a predictive factor for the occurrence of MRSA. The detection of CCs circulating in pigs and dairy cattle in Italy underscores the ability of the LA-MRSA clones to spread among animal production systems. In addition to maintaining preventive control measures for human health, better cleaning procedures need to be implemented, especially after new calves have been introduced into the herd.

Clonal spread of methicillin-resistant Staphylococcus pseudintermedius in Europe and North America: an international multicentre study.

OBJECTIVES: The aim of this study was to determine the phenotypic and genotypic resistance profiles of methicillin-resistant Staphylococcus pseudintermedius (MRSP) and to examine the clonal distribution in Europe and North America. METHODS: A total of 103 MRSP isolates from dogs isolated from several countries in Europe, the USA and Canada were characterized. Isolates were identified by PCR-restriction fragment length polymorphism (RFLP), antimicrobial susceptibility was determined by broth dilution or gradient diffusion, and antimicrobial resistance genes were detected using a microarray. Genetic diversity was assessed by multilocus sequence typing (MLST), PFGE and spa typing. Staphylococcal cassette chromosome mec (SCCmec) elements were characterized by multiplex PCR. RESULTS: Thirteen different sequence types (STs), 18 PFGE types and 8 spa types were detected. The hybrid SCCmec element II-III described in a MRSP isolate was present in 75 (72.8%) isolates. The remaining isolates either had SCCmec type III (n=2), IV (n=6), V (n=14) or VII-241 (n=4) or were non-typeable (n=2). The most common genotypes were ST71(MLST)-J(PFGE)-t02(spa)-II-III(SCCmec) (56.3%) and ST68-C-t06-V (12.6%). In addition to mecA-mediated beta-lactam resistance, isolates showed resistance to trimethoprim [dfr(G)] (90.3%), gentamicin/kanamycin [aac(6')-Ie-aph(2')-Ia] (88.3%), kanamycin [aph(3')-III] (90.3%), streptomycin [ant(6')-Ia] (90.3%), streptothricin (sat4) (90.3%), macrolides and/or lincosamides [erm(B), lnu(A)] (89.3%), fluoroquinolones (87.4%), tetracycline [tet(M) and/or tet(K)] (69.9%), chloramphenicol (cat(pC221)) (57.3%) and rifampicin (1.9%). CONCLUSIONS: Two major clonal MRSP lineages have disseminated in Europe (ST71-J-t02-II-III) and North America (ST68-C-t06-V). Regardless of their geographical or clonal origin, the isolates displayed resistance to the major classes of antibiotics used in veterinary medicine and thus infections caused by MRSP isolates represent a serious therapeutic challenge.