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Category: Bacterial Pathogenesis
rRNA Methylases and Resistance to Macrolide, Lincosamide, Streptogramin, Ketolide, and Oxazolidinone (MLSKO) Antibiotics, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555815615/9781555813031_Chap05-1.gif /docserver/preview/fulltext/10.1128/9781555815615/9781555813031_Chap05-2.gifAbstract:
All the macrolides, lincosamides, streptogramins, ketolides, and oxazolidinones (MLSKO) antibiotics inhibit protein synthesis by binding to the 50S bacterial ribosomal subunit, close to the peptidyltransferase center. The last group of acquired genes, and the focus of this chapter, are those that encode an adenine-N6-methyltransferase (rRNA methylase). Currently, 32 different genes coding for enzymes that modify the 23S rRNA have been described in the chapter. This modification blocks the binding of the MLSK group of antibiotics and allows the bacterial ribosomes to continue to produce protein in the presence of macrolides, lincosamides, and streptogramin B. Mobile elements often carry multiple different genes which confer antibiotic resistance to a variety of different antibiotic classes. Association of the erm genes with mobile elements (plasmids, conjugative transposons, and transposons) provides the potential to move from one species to another, one genus to another, and one ecosystem to another, between bacterial hosts, and from food to man and the environment. If DNA-DNA hybridization is used, confirmation by a PCR assay is advisable. One can speculate that as the newer macrolide derivatives became available in the 1980s this influenced the increase in carriage of macrolide resistance genes. It can be predicted that new innate genes may be found, which when mutated could provide increased levels of resistance to all the MSLKO antibiotics. It is even possible that new mechanisms of MLS resistance will be described in the coming years.
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Mechanism of MLS resistance a
Location of rRNA methylases in the published literature a
Linkage between rRNA methylase and other antibiotic resistance genes a