The Continuing Threat of Methicillin-Resistant Staphylococcus aureus

Abstract

Staphylococcus aureus has been an exceptionally successful pathogen, which is still relevant in modern age-medicine due to its adaptability and tenacity. This bacterium may be a causative agent in a plethora of infections, owing to its abundance (in the environment and in the normal flora) and the variety of virulence factors that it possesses. Methicillin-resistant S. aureus (MRSA) strains-first described in 1961-are characterized by an altered penicillin-binding protein (PBP2a/c) and resistance to all penicillins, cephalosporins, and carbapenems, which makes the β-lactam armamentarium clinically ineffective. The acquisition of additional resistance determinants further complicates their eradication; therefore, MRSA can be considered as the first representative of multidrug-resistant bacteria. Based on 230 references, the aim of this review is to recap the history, the emergence, and clinical features of various MRSA infections (hospital-, community-, and livestock-associated), and to summarize the current advances regarding MRSA screening, typing, and therapeutic options (including lipoglycopeptides, oxazolidinones, anti-MRSA cephalosporins, novel pleuromutilin-, tetracycline- and quinolone-derivatives, daptomycin, fusidic acid, in addition to drug candidates in the development phase), both for an audience of clinical microbiologists and infectious disease specialists.

Keywords: MRSA; SSCmec; Staphylococcus; ceftaroline; colonization; daptomycin; lipoglycopeptides; oxazolidinones; pleuromutilin; typing.

Figure 1

Cefoxitin-susceptible S. aureus on Mueller-Hinton-agar (antibiotic susceptibility-testing based on the Kirby-Bauer method) (left), Methicillin-resistant S. aureus (MRSA) screening using mannitol-salt agar (MSA) using cefoxitin disks (right).