aureus (MRSA) clones have rapidly emerged and spread worldwide and account for 10 to 30% of S. aureus infections [4, 5]. Molecular epidemiology studies using Multi Locus Sequence Typing (MLST) on clinical strains of S. aureus have shown that they are distributed into 11 major clonal complexes (CC) . MRSA strains represent the most threatening challenge as they are frequently resistant to many
antibiotics and there is evidence that antibiotic treatments not only facilitate the spreading of these find more clones but also enhance their pathogenicity . Patients with CF are at particular risk for pulmonary colonization of MRSA, both because of their difficulty in clearing mucus and because of their frequent hospital visits, which can increase exposure to MRSA. check details Several studies reported that 20 to 35% of CF patients harbored a MRSA strain and described the emergence of community-acquired MRSA (CA-MRSA) [8–11]. Methicillin-susceptible strains (MSSA) also constitute a risk in CF patients, particularly because of the existence of biofilms in the infected lung in which they can escape from antibiotic treatment . The epidemiology of S. aureus in CF patients has been investigated in different studies,
but mostly MRSA were analysed and the role of MSSA was not assessed. In order to extend the knowledge of the population of S. aureus chronically infecting CF patients, all the isolates should be systematically genotyped with a high degree of discrimination which is difficult using the currently available techniques. The polymorphism of the Staphylococcus protein A gene (spa), first used by Frenay et al.  to genotype S. aureus and further evaluated by Shopsin et al.  has proven to be very useful to investigate S. aureus genetic diversity. Subsequently MLST became the most widely used technique to analyse the epidemiology of S. aureus and to perform phylogenetic studies . Although the combined discriminatory power of spa typing and MLST is
high, these techniques GNE-0877 do not sufficiently discriminate within the major CCs and their cost is elevated. New approaches have been developed which use Variable Number of Tandem Repeats (VNTR) either to produce a multiple band pattern in a technique called MLVF [16, 17] or to perform Multiple loci VNTR analysis (MLVA). MLVA consists in the analysis of individual VNTRs allowing the description of a strain in the form of a code easily exchangeable between laboratories . MLVA with 6 VNTRs could correctly assigned isolates to outbreaks or identified isolates as Selleckchem LY2835219 unlinked . Schouls et al. using 8 VNTRs showed that MLVA was at least as discriminatory as Pulse Field Gel electrophoresis (PFGE) and twice as discriminatory as spa-sequence typing . Finally we recently described a very informative MLVA scheme which makes use of 14 VNTRs (MLVA-14) and demonstrated that its discriminatory power was much higher than those of MLST and spa typing .