## 3 Results and Discussion
### Safety Assessment of Ventricina Del Vastese CNS  
Among the CNS isolates examined, a minority were found to bear hazardous traits, with four strains of _S. xylosus_ potentially able to form tyramine due to the presence of a _tdc_A gene and seven strains harboring AR determinants (Figure 2). The AR genes found in this study, _blaZ_ and _tet_K, were reported to be frequent in CNS [7, 8], whereas the _mcc_A conferring methicillin resistance and the _mrs_A encoding a macrolide efflux protein previously found in some of the species identified in this study [7, 8] were absent in the isolates from Ventricina del Vastese sausage. In addition, the gene _blaZ_, reported by [PERSON] et al. [8] to be the most prevalent in sausage-associated CNS, was infrequent in this study. As a strong correlation was found between the presence of _blaZ_ and _tet_K and a phenotypic resistance to penicillin and tetracycline, respectively [8], the CNS isolates carrying these genes found in this study are likely phenotypically resistant as well.  
Importantly, no multidrug resistance (MDR) genetic profiles were observed, with only one strain possessing two AR genes, _tet_K and _tet_A. The gene _tet_K is plasmid-encoded in _S. aureus_[31] and, therefore, is prone to be transferred. On the other hand, the gene _tet_A found in this study was not previously detected in CNS from food, and, through a database search, it was found to be chromosomally encoded in an _S. colniti_ clinical isolate (Acc. N. Accession: UHEC01000001.1) among CNS and in coagulase-positive staphylococci.  
Notably, the AR gene-harboring isolates found in this study were mostly associated with a single manufacturer, with only one exception, suggesting a localized selection of AR CNS. Therefore, examining bacterial isolates for AR might be useful to identify trends of AR bacteria selection at a farm level.  
Staphylococcal enterotoxins were absent in the isolates obtained in this study, which is different than the findings by [PERSON] et al. [32] who isolated _S. epidermidis_, _S. succinus_, _S. xylosus_ and _S. saprophyticus_ strains which harbored most often _seb_/_sec_ and _sea_, followed by _sed_/_seln_/_seln_ and _sei_/_seln_ and were also expressed in vitro. Finally, weak hemolytic activity was only found in the isolate _S. succinus_ subsp. _casei_ A27.  
The low frequency of the AR genes in CNS from Ventricina del Vastese sausage and the absence of MDR are indicative of a production process in which selective pressure for AR is weak, possibly because of the little need for antibiotic usage in animals raised in small farms with extensive rearing systems. Indeed, [PERSON] et al. [33] observed that extensive farming for artisanal sausage production determines a low occurrence of AR genes in CNS compared to production on an industrial scale with animals farmed intensively. However, even a low level of AR gene occurrence in CNS from Ventricina del Vastese indicates the need to monitor the spread of these genes and adopt measures that reduce their presence.  
The effectiveness of autochthonous starter cultures including CNC in improving the safety of fermented sausages was demonstrated by the reduction in BA formation [34]. Therefore, the isolation and characterization of CNS present in Ventricina del Vastese, as well as in other similar products, are indispensable to allow the selection of strains to be tested as autochthonous starters eventually able to reduce BA formation and the occurrence of strains with risk factors such as transferable AR genes.