Molecular characterization of a novel mosaic tet(S/M) gene encoding tetracycline resistance in foodborne strains of Streptococcus bovis

Genomics, evolution, and molecular epidemiology of the Streptococcus bovis / Streptococcus equinus complex (SBSEC)

“…However, tet(M)-encoded tetracycline resistance was found in 39 out of 45 S. bovis (unknown biotypes) isolates from Italian raw-milk cheese (Devirgiliis et al, 2010). The tet(M) gene turned out to be part of a novel mosaic tet(S/M) gene (Barile et al, 2012) most probably originating from a fusion of CTn6000 and CTn916 (Novais et al, 2012). Vancomycin resistance in SBSEC is so far not widespread, but concerning, since vanB transferable to enterococci was detected in a S. bovis human stool isolate (Poyart et al, 1997) and vanA and vanB or both genes together in S. gallolyticus isolates from faeces in Dutch calves (Mevius et al, 1998).…”

Mosaic tetracycline resistance genes encoding ribosomal protection proteins

“…tet (O/W/32/O/W/O)] different regions (Figure 1), with tet (O), tet (W) and tet (32) being the predominant RPP genes reported to form mosaic genes, comprising all but two of the reported variants, and tet (M) and tet (S) forming the remaining two. 24,25 Given the prevalence of tet (M) in certain samples, and the previous reports of self-recombination, 14,26 it is surprising that there are so few reports of mosaic genes containing tet (M). Furthermore, alignment of 12 representative RPP gene sequences shows tet (M) sharing 75% and 70% identity, respectively, to tet (O) and tet (44), which is higher than the percentage identity observed between the more commonly reported RPP mosaic genes comprising tet (O), (W) and (32) (Table 2).…”

Food and human gut as reservoirs of transferable antibiotic resistance encoding genes

“…AR clinical isolates of E. coli that were indistinguishable from chicken isolates have also been reported in Barcelona, Spain and in Minnesota and Wisconsin, the United States, suggesting that foodborne transmission of AR ExPEC is a very common phenomenon and is a major source of AR genes transmissible to humans via the food chain (Johnson et al, 2006,2007). A novel mosaic tetracycline resistance-encoding gene, tet(S/M), in a transposon likely acquired from Lactococcus lactis , has been described in foodborne strains of Streptococcus bovis , a human opportunistic pathogen (Barile et al, 2012). …”