Linezolid-resistantcfr-positive MRSA, Italy

Sir, Infections caused by MRSA remain a major healthcare problem worldwide, and oxazolidinones are among the most important treatment options for MRSA infections. Linezolid-resistant MRSA (LR-MRSA) has been reported since the early 2000s, but their prevalence has remained overall low. In MRSA, oxazolidinone resistance can be mediated by chromosomal mutations in genes encoding the 23S rRNA or the L3 and L4 ribosomal proteins, or by acquisition of the cfr gene encoding 23S rRNA methylase. The latter mechanism is transferable and confers resistance to several anti-ribosomal drugs including phenicols, lincosamides, oxazolidinones, pleuromutilins, streptograminA and certain 16 membered-ring macrolides.1 The first LR-MRSA carrying the cfr gene was detected in the USA in 2005, from a patient with cystic fibrosis (CF).2 Thus far, cfr-positive MRSA strains have been reported from several countries, sporadically or even causing hospital outbreaks.3 In Europe, cfr-positive MRSA has been reported from Germany and Spain, where similar strains have recently been reported also from patients with CF.4,5