Bovine mastitis (BM) has caused huge economic and financial losses in the dairy industry worldwide, with Staphylococcus aureus as one of its major pathogens. BM treatment still relies on antibiotics and its extensive use often generates methicillin-resistant S. aureus (MRSA) and mupirocin-resistant S. aureus (MuRSA). This study compared the antimicrobial resistance trend in coagulase-positive Stapholococci (CoPS) isolated from BM milk in conventional and organic dairy farms and checked prevalence of MRSA and MuRSA. A total of 163 presumptive Staphylococci were isolated, wherein 11 out of 74 from 4 conventional farms (CF1, CF2, CF3, CF4) and 17 out of 89 from 3 organic farms (OF1, OF2, OF3) exhibited coagulase activity. Multiplex-PCR amplification confirmed at least one coagulase-positive isolate from CF1, CF2, CF3, CF4, and OF1 as S. aureus, denoted by the presence of the nuc gene. Three isolates from CF2 contained the mecA gene, indicating MRSA prevalence, while the MuRSA gene marker, mupA, was not detected in any of the isolates. Antimicrobial testing showed that conventional farm isolates were more resistant to antibiotics, especially ampicillin and tetracycline. This suggests a risk of developing multidrug resistance in dairy farms if antibiotic use is not properly and strictly monitored and regulated.

Staphylococci are responsible for many infections in humans, starting with skin and soft tissue infections and finishing with invasive diseases such as endocarditis, sepsis and pneumonia, which lead to high mortality. Patients with sepsis often demonstrate activated clotting pathways, decreased levels of anticoagulants, decreased fibrinolysis, activated endothelial surfaces and activated platelets. This results in disseminated intravascular coagulation and formation of a microthrombus, which can lead to a multiorgan failure. This review describes various staphylococcal virulence factors that contribute to vascular thrombosis, including deep vein thrombosis in infected patients. The article presents mechanisms of action of different factors released by bacteria in various host defense lines, which in turn can lead to formation of blood clots in the vessels.

A profile of the microbial safety and hygiene of cheese in central Italy was defined based on an analysis of 1373 cheeses sampled under the Italian National Control Plan for Food Safety spanning the years 2013 to 2020 and tested according to Commission Regulation (EC) No. 2073/2005 (as amended). A total of 97.4% of cheese samples were assessed as being satisfactory for food safety criteria and 80.5% for process hygiene criteria. Staphylococcal enterotoxin was found in 2/414 samples, while Salmonella spp. and Listeria monocytogenes were detected in 15 samples out of 373 and 437, respectively. Escherichia coli and coagulase-positive staphylococci counts were found unsatisfactory in 12/61 and 17/88 cheese samples, respectively. The impact of milking species, milk thermal treatment, and cheese hardness category was considered. A statistically significant association (p < 0.05) was found between milk thermal treatment and the prevalence of coagulase-positive staphylococci and Listeria monocytogenes and between hardness and unsatisfactory levels of Escherichia coli. The data depict a contained public health risk associated with these products and confirm, at the same time, the importance of strict compliance with good hygiene practices during milk and cheese production. These results can assist in bolstering risk analysis and providing insights for food safety decision making.

Staphylococcal enterotoxins preformed in food are the causative agents of staphylococcal food poisoning outbreaks (SFPO). In this study we characterised in depth two coagulase-positive non-pigmented staphylococci involved in two independent outbreaks that occurred in France. While indistinguishable from Staphylococcus aureus using PCR methods and growth phenotype comparisons, both isolates were identified as Staphylococcus argenteus by whole genome sequencing. The genomes were analysed for the presence of enterotoxin genes, whose expression was determined in laboratory medium and, for the first time, in artificially-contaminated milk samples by using liquid chromatography-mass spectrometry and ELISA methods. The concentration measured for the SEB toxin in milk (0.67 ng/ml) was comparable to concentrations reported for other types of enterotoxins behind SFPO. From a collection of publicly available genomes, we performed an unprecedented systematic investigation of the enterotoxin gene set of S. argenteus, including variants and pseudogenes. The most prevalent genes were sex, followed by sel26, sel27 and sey. The egc cluster was less frequent and most of the time carried a dysfunctional seg gene. Our results shed light on the enterotoxigenic properties of S. argenteus, and emphasize the importance in monitoring of S. argenteus as an emerging foodborne pathogen.

Coagulase-positive staphylococci (CPS) are common cutaneous pathogens often requiring multiple courses of antibiotics, which may facilitate selection for methicillin-resistant (MR) and/or multidrug-resistant (MDR) strains. To determine the prevalence of canine and feline MR/MDR CPS associated with skin diseases, medical records were retrospectively searched from April 2010 to April 2020. Pets with at least one positive culture for CPS were selected. Age, sex, antimicrobial sensitivity, previous history of antimicrobial/immunomodulatory medications and methicillin resistance/multidrug resistance status were recorded. Staphylococcus pseudintermedius (SP) (575/748) and Staphylococcus schleiferi (SS) (159/748) in dogs, and Staphylococcus aureus (12/22) in cats, were the most common CPS isolated. Three hundred and twenty-three out of 575 isolates were MR-SP (56.2 %), 304/575 were MDR-SP (52.8 %), 100/159 were MR-SS (62.9 %) and 71/159 were MDR-SS (44.6 %). A trend analysis showed a significant increase of resistance to oxacillin and chloramphenicol for S. pseudintermedius (r=0.86, 0.8; P=0.0007, 0.0034, respectively). Major risk factors for MDR-SP included oxacillin resistance (OR: 3; 95 % CI: 1.4-6.5; P=0.0044), positivity for PBP2a (OR: 2.3; 95 % CI: 1-5; P=0.031) and use of antibiotics in the previous year (OR: 2.8; 95 % CI: 1.3-5.8; P=0.0071). Oxacillin resistance was identified as a major risk factor for MDR-SS (OR: 8.8; 95 % CI: 3.6-21.1; P<0.0001). These results confirmed the widespread presence of MR/MDR CPS in referred dermatological patients. Judicious antibiotic use, surveillance for MR/MDR infections and consideration of alternative therapies are crucial in mitigating the development of resistant strains.

Coagulase positive Staphylococci (CoPS) are the leading cause of canine cutaneous and otic infections. Virulence factors associated with Staphylococci include the expression of mec and panton-valentine leukocidin (pvl) genes. Methicillin-resistance (MR) is commonly associated with mecA gene expression, although a recently identified variant, mecC, has been reported. This study aims to evaluate the prevalence of mecA, mecC and pvl genes in 232 clinical isolates of CoPS collected from dogs with pyoderma. A multiplex PCR, and Kirby-Bauer disk diffusion susceptibility test for cefoxitin was performed for all isolates. PBP2a agglutination test was performed on 127 isolates. Standard MRSA isolates were used as positive controls. The mecA gene was identified in 149/232 isolates (64.2%): 116 S. pseudintermedius, 30 S. coagulans and three S. aureus. The pvl gene was present in only 1 isolate of S. pseudintermedius (0.4%), whereas no isolates carried the mecC gene. 34 isolates were resistant to cefoxitin (14.6%) and they were all mecA positive. The results of this study show an MR prevalence of 64.2% confirming concerns about antibiotic resistance in veterinary medicine. In conclusion, this is the first study analyzing the prevalence of mecC and pvl in comparison to mecA, in a large cohort of CoPS clinical isolates from dogs with pyoderma. A multimodal surveillance on the prevalence of mecC and pvl in veterinary medicine is essential to appropriate antimicrobial management.

Bacteriocins are antimicrobial peptides with relevance in the modulation of human and animal microbiota that have gained interest in biomedical and biotechnological applications. In this study, the production of bacteriocin-like inhibitory substances (BLIS) was tested among a collection of 890 staphylococci of different origins (humans, animals, food, and the environment) and species, both coagulase-positive (CoPS, 238 isolates of 3 species) and coagulase-negative staphylococci (CoNS, 652 isolates of 26 species). Of the 890 staphylococci, 60 (6.7%) showed antimicrobial activity by the spot-on-lawn method against at least one of the 25 indicator bacteria tested. BLIS-producer (BLIS+) isolates were detected in 8.8% of CoPS and 6.0% of CoNS. The staphylococcal species with the highest percentages of BLIS+ isolates were S. chromogenes (38.5%), S. pseudintermedius (26.7%), and S. warneri (23.1%). The production of BLIS was more frequently detected among isolates of pets, wild animals, and food. Moreover, 13 BLIS+ isolates showed wide antimicrobial activiy spectrum, and 7 of these isolates (of species S. aureus, S. pseudintermedius, S. sciuri, and S. hominis) demonstrated antimicrobial activity against more than 70% of the indicator bacteria tested. The genetic characterization (by PCR and sequencing) of the 60 BLIS+ isolates revealed the detection of (a) 11 CoNS and CoPS isolates carrying putative lantibiotic-like genes; (b) 3 S. pseudintermedius isolates harboring the genes of BacSp222 bacteriocin; and (c) 2 S. chromogenes isolates that presented the gene of a putative cyclic bacteriocin (uberolysin-like), being the first report in this CoNS species. Antimicrobial susceptibility testing was performed in BLIS+ isolates and one-third of the CoNS isolates showed susceptibility to all antibiotics tested, which also lacked the virulence genes studied. These BLIS+ CoNS are good candidates for further characterization studies.

Staphylococcal food poisoning outbreaks are caused by the ingestion of food contaminated with staphylococcal enterotoxins (SEs). Among the 27 SEs described in the literature to date, only a few can be detected using immuno-enzymatic-based methods that are strongly dependent on the availability of antibodies. Liquid chromatography, coupled to high-resolution mass spectrometry (LC-HRMS), has, therefore, been put forward as a relevant complementary method, but only for the detection of a limited number of enterotoxins. In this work, LC-HRMS was developed for the detection and quantification of 24 SEs. A database of 93 specific signature peptides and LC-HRMS parameters was optimized using sequences from 24 SEs, including their 162 variants. A label-free quantification protocol was established to overcome the absence of calibration standards. The LC-HRMS method showed high performance in terms of specificity, sensitivity, and accuracy when applied to 49 enterotoxin-producing strains. SE concentrations measured depended on both SE type and the coagulase-positive staphylococci (CPS) strain. This study indicates that LC-MS is a relevant alternative and complementary tool to ELISA methods. The advantages of LC-MS clearly lie in both the multiplex analysis of a large number of SEs, and the automated analysis of a high number of samples.

BACKGROUND: This study investigated the eggs of Polish-bred edible snails of the Cornu genus as a food and aimed to determine the presence of microorganisms in them of the Salmonella and Listeria genera and ascertain the number of coagulase-positive staphylococci.
METHODS: Raw material, semi-finished products, and the final product were collected during the production cycle. Testing for the presence of Salmonella spp. and Listeria spp. and measuring of the pathogenic staphylococci contamination level were carried out in accordance with ISO standards. Commercial biochemical tests were used for species identification of bacteria of the Enterobacteriaceae family and Staphylococcus genus. An API kit and a PCR protocol were utilised for species confirmation of the microorganisms of the Listeria genus.
RESULTS: Neither Salmonella nor coagulase-positive staphylococci were found in any of the studied material. Bacteria of the Listeria genus were found in samples taken at every stage of production; however L. monocytogenes was confirmed in samples of the final product.
CONCLUSIONS: The absence of Salmonella spp. and Staphylococcus aureus in samples of the final product indicates that the required hygiene standard was maintained in the production process of edible snail eggs. Nevertheless, the presence of L. monocytogenes in eggs of common garden snails may pose a potential risk to consumer health.

The main objectives of the present study were to determine the occurrence of coagulase positive staphylococci (CPS) and to assess the presence and antimicrobial susceptibility profile of Staphylococcus aureus isolates in different raw milk origin (cow and sheep) traditional cheeses marketed in Banat region, Romania. Additionally, the presence of mecA gene in S. aureus isolates and the staphylococcal enterotoxins (SEs) in cheese samples were evaluated. A total of 81.6% (138/169) of the screened samples were positive for CPS. Furthermore, 35.5% (49/138) of the investigated CPS positive cheese samples were contaminated with S. aureus, with an isolation frequency of 46.6% (14/30) in caș, 33.3% (32/96) in telemea, 25% (2/8) in burduf, and 25% (1/4) in urdă assortments, respectively. From the total number of S. aureus isolates, 6.1% (3/49) harbored the mecA gene. Detectable levels of SEs were identified in 4.3% (4/94) of cheese samples with a CPS contamination level higher than 105 log CFU g-1. The expressed antimicrobial susceptibility profile of the tested cheese-origin S. aureus isolates, with the automated Vitek 2 equipment, showed resistance towards amikacin (90.1%, 10 out from 11 tested), enrofloxacin (86.2%, 25/29), ceftiofur (72.7%, 8/11), neomycin (63.6%, 7/11), benzylpenicillin (53.1%, 26/49), kanamycin (41.4%, 12/29), rifampicin (39.5%, 15/38), tetracycline (38.8%, 19/49), tilmicosin (36.4%, 4/11), clindamycin (30.6%, 15/49), ciprofloxacin (30%, 6/20), erythromycin (22.4%, 11/49), tylosin (18.2%, 2/11), oxacillin (16.3%, 8/49), linezolid (15%, 3/20), teicoplanin (15%, 3/20), fusidic acid (13.1%), imipenem (10.5%, 4/38), vancomycin (7.9%, 3/38), ampicillin (5.5%, 1/18), mupirocin (5.5%, 1/18), fosfomycin (5%, 1/20), and gentamicin (4.1%, 2/49). Twenty-four (49%) S. aureus isolates exhibited multidrug resistance. The investigation highlighted a common occurrence of multidrug-resistant S. aureus strains in the monitored cheese assortments, which can constitute a potential risk for consumers\' health.