We report the spread of a clone of multidrug-resistant (MDR), ESBL-producing (bla CTX-M-1) Salmonella enterica subsp. enterica serovar Infantis, in the Italian broiler chicken industry and along the food-chain. This was first detected in Italy in 2011 and led to human infection in Italy in 2013–2014.A set (n = 49) of extended-spectrum cephalosporin (ESC)-resistant (R) isolates of S. Infantis (2011–2014) from humans, food-producing animals and meat thereof, were studied along with a selected set of earlier and more recent ESC-susceptible (ESC-S) isolates (n = 42, 2001–2014). They were characterized by macrorestriction-PFGE analysis and genetic environment of ESC-resistance. Isolates representative of PFGE-patterns and origin were submitted to Whole Genome Sequencing. The emerging ESC-R clone, detected mainly from broiler chickens, broiler meat and humans, showed a minimum pattern of clinical resistance to cefotaxime, tetracycline, sulfonamides, and trimethoprim, beside ciprofloxacin microbiological resistance (MIC 0.25 mg/L). All isolates of this clone harbored a conjugative megaplasmid (~ 280–320 Kb), similar to that described in ESC-susceptible S. Infantis in Israel (pESI-like) in 2014. This megaplasmid carried the ESBL gene bla CTX-M-1, and additional genes [tet(A), sul1, dfrA1 and dfrA14] mediating cefotaxime, tetracycline, sulfonamide, and trimethoprim resistance. It also contained genes conferring enhanced colonization capability, virulence (fimbriae, yersiniabactin), resistance and fitness (qacE1, mer) in the intensive-farming environment. This emerging clone of S. Infantis has been causing infections in humans, most likely through the broiler industry. Since S. Infantis is among major serovars causing human infections in Europe and is an emerging non-typhoidal Salmonella globally, further spread of this lineage in primary productions deserves quick and thorough risk-management strategies.

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S taphylococcus aureus is a major pathogen causing considerable human morbidity and mortality worldwide, and it is a leading cause of infections of some economically important livestock species and, as a prominent bacterial cause of contagious bovine mastitis, a major economic burden for the dairy cattle industry (1). Methicillin-resistant S. aureus (MRSA) lineages are causes of health care-and community-associated infections, which are a major burden of disease on a global scale (2). In the last decade, MRSA sequence type 398 (ST398) has found an ecological niche in the pig, cattle, and poultry industries, although other MRSA lineages (e.g., ST1, ST5, ST9, ST97, ST130, and ST433) have been identified in farmed animals worldwide (3) All these lineages are currently termed "livestock-associated MRSA" (LA-MRSA).The MRSA clonal complex 97 (CC97) lineage has been reported as the second most prevalent MRSA lineage in the Italian pig industry, where spa types t1730 and t4795, both belonging to ST97, were estimated to have colonized 11% of finishing holdings (4). In Italy, in the last 5 years, the CC97 MRSA lineage has also been increasingly detected in cattle primary production, either from mastitis in dairy cattle or from bulk tank milk (5-7). Occasionally, CC97 MRSA isolates have been detected in cattle in Germany and Spain.CC97 is one of the major S. aureus clonal complexes in bovines (8), and recently, a livestock origin of the human pandemic CC97 MRSA strains has been demonstrated, resulting in two emergent human epidemic CC97 community-acquired/associated MRSA (CA-MRSA) clones (8).The aim of this study was to determine the genetic relatedness of MRSA and methicillin-susceptible S. aureus (MSSA) CC97 isolates from pigs and dairy cattle in Italy in the last few years (2008 to 2012) for epidemiological and risk assessment purposes.

Methicillin-resistant Staphylococcus aureus (MRSA) Sequence Type (ST)1, Clonal Complex(CC)1, SCCmec V is one of the major Livestock-Associated (LA-) lineages in pig farming industry in Italy and is associated with pigs in other European countries. Recently, it has been increasingly detected in Italian dairy cattle herds. The aim of this study was to analyse the differences between ST1 MRSA and methicillin-susceptible S. aureus (MSSA) from cattle and pig herds in Italy and Europe and human isolates. Sixty-tree animal isolates from different holdings and 20 human isolates were characterized by pulsed-field gel electrophoresis (PFGE), spa-typing, SCCmec typing, and by micro-array analysis for several virulence, antimicrobial resistance, and strain/host-specific marker genes. Three major PFGE clusters were detected. The bovine isolates shared a high (≥90% to 100%) similarity with human isolates and carried the same SCCmec type IVa. They often showed genetic features typical of human adaptation or present in human-associated CC1: Immune evasion cluster (IEC) genes sak and scn, or sea; sat and aphA3-mediated aminoglycoside resistance. Contrary, typical markers of porcine origin in Italy and Spain, like erm(A) mediated macrolide-lincosamide-streptograminB, and of vga(A)-mediated pleuromutilin resistance were always absent in human and bovine isolates. Most of ST(CC)1 MRSA from dairy cattle were multidrug-resistant and contained virulence and immunomodulatory genes associated with full capability of colonizing humans. As such, these strains may represent a greater human hazard than the porcine strains. The zoonotic capacity of CC1 LA-MRSA from livestock must be taken seriously and measures should be implemented at farm-level to prevent spill-over.

We report the genetic characterization of 15 Klebsiella pneumoniae (KP) and 4 isolates of K. oxytoca (KO) from clinical cases in dogs and cats and showing extended-spectrum cephalosporin (ESC) resistance. Extended spectrum beta-lactamase (ESBL) and AmpC genes, plasmid-mediated quinolone resistance (PMQR) and co-resistances were investigated. Among KP isolates, ST101 clone was predominant (8/15, 53%), followed by ST15 (4/15, 27%). ST11 and ST340, belonging to Clonal Complex (CC)11, were detected in 2012 (3/15, 20%). MLST on KP isolates corresponded well with PFGE results, with 11 different PFGE patterns observed, including two clusters of two (ST340) and four (ST101) indistinguishable isolates, respectively. All isolates harbored at least one ESBL or AmpC gene, all carried on transferable plasmids (IncR, IncFII, IncI1, IncN), and 16/19 were positive for PMQR genes (qnr family or aac(6′)-Ib-cr). The most frequent ESBL was CTX-M-15 (11/19, 58%), detected in all KP ST101, in one KP ST15 and in both KP ST340. bla CTX-M-15 was carried on IncR plasmids in all but one KP isolate. All KP ST15 isolates harbored different ESC resistance genes and different plasmids, and presented the non-transferable bla SHV-28 gene, in association with bla CTX-M-15, bla CTX-M-1 (on IncR, or on IncN), bla SHV-2a (on IncR) or bla CMY-2 genes (on IncI1). KO isolates were positive for bla CTX-M-9 gene (on IncHI2), or for the bla SHV-12 and bla DHA-1 genes (on IncL/M). They were all positive for qnr genes, and one also for the aac(6′)-Ib-cr gene. All Klebsiella isolates showed multiresistance towards aminoglycosides, sulfonamides, tetracyclines, trimethoprim and amphenicols, mediated by strA/B, aadA2, aadB, ant (2")-Ia, aac(6′)-Ib, sul, tet, dfr and cat genes in various combinations. The emergence in pets of multidrug-resistant Klebsiella with ESBL, AmpC and PMQR determinants, poses further and serious challenges in companion animal therapy and raise concerns for possible bi-directional transmission between pets and humans, especially at household level.