S. equorum is used as one of the starter cultures in the preparation of smear-ripened cheese and cured meats such as sausages [15, 16]. Since S. equorum present in retail meats has rare chances of coming in contact with antimicrobial agents, click here the origin and high prevalence of cfr in Staphylococcus equorum is intriguing. The cfr-carrying segment (including rep, Δpre/mob, cfr, pre/mob and partial ermC) on the plasmid pHNLKJC2 from the chicken meat strain S. sciuri TLKJC2, was found to be similar to the corresponding plasmid regions from different staphylococcal species such as the plasmid pSS-03 (accession number JQ219851) from a bovine S. cohnii strain and the plasmid pMSA16
(accession number JQ246438) from a bovine MRSA ST9 strain in China (Figure
1B) [10, 18]. In addition, this cfr-carrying segment also showed high nucleotide Osimertinib manufacturer sequence identity (98%) to the corresponding region of plasmid pSCFS1 (accession number AJ579365) from a bovine S. sciuri in Germany [19]. The cfr-carrying segment (including ΔtnpA of Tn558, IS21-558; ΔtnpB; and tnpC of Tn558, orf138, fexA) on the plasmid pHNTLD18 from the pork strain S. equorum TLD18 was identical to the corresponding segment of the plasmid pHK01 (accession number KC820816) found in S. cohnii from human in China [20], the plasmid pSA737 (accession number KC206006) extracted from a human clinical MRSA strain and the plasmid pSEPI8573 (accession number KC222021) from a human clinical S. epidermidis strain in the United States [21], and the plasmid selleckchem pSS-02 (accession number JF834910) obtained from a porcine S. saprophyticus strain in China(Figure 1A) [10].
These results indicated that the horizontal transfer mediated by mobile genetic elements such as plasmids and insertion sequences may Thalidomide contribute to the spread of cfr and suggested that it is possible to transfer cfr via mobile genetic elements from staphylococcal isolates of animal origin to the bacterial strains in the human body through meat consumption, posing a serious threat to the public health. The MICs of the cfr-positive staphylococci indicated multiresistance phenotype in these strains other than the PhLOPSA phenotype, suggesting limited therapeutic options to control these cfr-carrying staphylococci. Most of the cfr-positive staphylococcal isolates showed low-level linezolid resistance with MIC values ranging from 4 to 16 mg/L; this result is in agreement with previously reported linezolid MICs among cfr-carrying staphylococci from farm animals and humans [10, 11, 22]. In addition, five of the cfr-positive isolates had linezolid MIC values of 2 mg/L, which is the same as the typical linezolid MIC90 value and not consistent with MIC value shifts observed for isogenic cfr-negative/positive staphylococcal strain pairs [23].