High-level mupirocin resistance within methicillin-resistant Staphylococcus aureus pandemic lineages

Mupirocin resistance in Staphylococcus aureus: A systematic review and meta-analysis

OBJECTIVES

Staphylococcus aureus is one of the most common pathogens causing nosocomial and community-acquired infections associated with high morbidity and mortality. Mupirocin has been increasingly used for treatment of methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) infections. The aim of this study was to determine the prevalence of mupirocin-resistant S. aureus (MuRSA), mupirocin-resistant MRSA (MuRMRSA), high-level MuRSA (HLMuRSA) and high-level MuRMRSA (HLMuRMRSA) worldwide.

METHODS

Online databases including Medline, Embase and Web of Science were searched (2000-2018) to identify studies addressing the prevalence of MuRSA, MuRMRSA, HLMuRSA and HLMuRMRSA. STATA v. software was used to interpret the data.

RESULTS

Of the 2243 records identified from the databases, 30 and 63 studies fulfilled the eligibility criteria for MuRSA and MuRMRSA, respectively. Finally, 27 and 60 studies were included separately for HLMuRSA and HLMuRMRSA, respectively. The analyses revealed pooled and averaged prevalences of MuRSA, MuRMRSA, HLMuRSA and HLMuRMRSA of 7.6% [95% confidence interval (CI) 6.2-9.0%], 13.8% (95% CI 12.0-15.6%), 8.5% (95% CI 6.3-10.7%) and 8.1% (95% CI 6.8-9.4%), respectively.

CONCLUSION

Overall, these results show a global increase in the prevalence of HLMuRSA and HLMuRMRSA among clinical S. aureus isolates over time. However, there was only a significant increase in the prevalence of MuRMRSA compared with the other categories, especially MuRSA. Since mupirocin remains the most effective antibiotic for MSSA and MRSA decolonisation both in patients and healthcare personnel, a reduction of its effectiveness presents a risk for invasive infection. Monitoring of mupirocin resistance development remains critical.

A review on mechanism of action, resistance, synergism, and clinical implications of mupirocin against Staphylococcus aureus

Mupirocin (MUP), bactroban, or pseudomonic acid is a natural crotonic acid derivative drug extracted from Pseudomonas fluorescens which is produced by modular polyketide synthases. This antibiotic has a unique chemical structure and mechanism of action. It is a mixture of A-D pseudomonic acids and inhibits protein synthesis through binding to bacterial isoleucyl-tRNA synthetase. MUP is often prescribed to prevent skin and soft tissue infections caused by S. aureus isolates and where the MRSA isolates are epidemic, MUP may be used as a choice drug for nasal decolonization. It is also used for prevention of recurring infections and control the outbreaks. The emergence of MUP resistance has been increasing particularly among methicillin-resistant Staphylococcus aureus (MRSA) isolates in many parts of the world and such resistance is often related with MUP widespread uses. Although both low-level and high-level MUP resistance were reported among MRSA isolates, the rate of resistance is different in various geographic areas. In this review, we will report the global prevalence of MUP resistance, discuss synergism and mechanism of action of MUP, and provide new insights into the clinical use of this antibiotic.

Mobile Genetic Elements Associated with Antimicrobial Resistance

Strains of bacteria resistant to antibiotics, particularly those that are multiresistant, are an increasing major health care problem around the world. It is now abundantly clear that both Gram-negative and Gram-positive bacteria are able to meet the evolutionary challenge of combating antimicrobial chemotherapy, often by acquiring preexisting resistance determinants from the bacterial gene pool. This is achieved through the concerted activities of mobile genetic elements able to move within or between DNA molecules, which include insertion sequences, transposons, and gene cassettes/integrons, and those that are able to transfer between bacterial cells, such as plasmids and integrative conjugative elements. Together these elements play a central role in facilitating horizontal genetic exchange and therefore promote the acquisition and spread of resistance genes. This review aims to outline the characteristics of the major types of mobile genetic elements involved in acquisition and spread of antibiotic resistance in both Gram-negative and Gram-positive bacteria, focusing on the so-called ESKAPEE group of organisms (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp., and Escherichia coli), which have become the most problematic hospital pathogens.

Antimicrobial Resistance to Agents Used for Staphylococcus aureus Decolonization: Is There a Reason for Concern?

PURPOSE OF REVIEW

Chlorhexidine gluconate (CHG) and mupirocin are increasingly used for Staphylococcus aureus decolonization to prevent healthcare-associated infections; however, increased use of these agents has led to concerns for growing resistance and reduced efficacy. In this review, we describe current understanding of reduced susceptibility to CHG and mupirocin in S. aureus and their potential clinical implications.

RECENT FINDINGS

While emergence of S. aureus tolerant or resistant to topical antimicrobial agents used for decolonization is well described, the clinical impact of reduced susceptibility is not clear. Important challenges are that standardized methods of resistance testing and interpretation are not established, and the risk for selection for co- or cross-resistance using universal, as opposed to targeted decolonization, is unclear. Evidence continues to support S. aureus decolonization in certain patient groups, although further studies are needed to determine the long-term impact of CHG and mupirocin resistance on efficacy. Strategies to mitigate further development of reduced susceptibility and the consequences of selection pressures through universal decolonization on resistance will benefit from further investigation.

Six-Year Retrospective Review of Hospital Data on Antimicrobial Resistance Profile of Staphylococcus aureus Isolated from Skin Infections from a Single Institution in Greece

Objective: To determine the prevalence of resistant strains of Staphylococcus aureus (S. aureus) isolated from Skin and soft tissue infections (SSTI) to various antibiotics. Material and Methods: All culture-positive results for S. aureus from swabs taken from patients presenting at one Greek hospital with a skin infection between the years 2010–2015 were examined retrospectively. Bacterial cultures, identification of S. aureus and antimicrobial susceptibility testing were performed using the disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI) guidelines and European Committee on Antimicrobial testing (EUCAST) breakpoints. EUCAST breakpoints were applied if no CLSI were available. Results: Of 2069 S. aureus isolates identified, 1845 (88%) were resistant to one or more antibiotics. The highest resistance was observed for benzylpenicillin (71.9%), followed by erythromycin (34.3%). Resistant strains to cefoxitin defined as MRSA (methicillin-resistant S. aureus) represented 21% of total isolates. Interestingly, resistance to fusidic acid was 22.9% and to mupirocin as high as 12.7%. Low rates were observed for minocycline, rifampicin and trimethoprim/sulfamethoxazole (SXT). Resistance to antibiotics remained relatively stable throughout the six-year period, with the exception of cefoxitin, fusidic acid and SXT. A high percentage of MRSA strains were resistant to erythromycin (60%), fusidic acid (46%), clindamycin (38%) and tetracycline (35.5%). Conclusions: Special attention is required in prescribing appropriate antibiotic therapeutic regimens, particularly for MRSA. These data on the susceptibility of S. aureus may be useful for guiding antibiotic treatment.

Current and Emerging Topical Antibacterials and Antiseptics: Agents, Action, and Resistance Patterns

Bacterial skin infections represent some of the most common infectious diseases globally. Prevention and treatment of skin infections can involve application of a topical antimicrobial, which may be an antibiotic (such as mupirocin or fusidic acid) or an antiseptic (such as chlorhexidine or alcohol). However, there is limited evidence to support the widespread prophylactic or therapeutic use of topical agents. Challenges involved in the use of topical antimicrobials include increasing rates of bacterial resistance, local hypersensitivity reactions (particularly to older agents, such as bacitracin), and concerns about the indiscriminate use of antiseptics potentially coselecting for antibiotic resistance. We review the evidence for the major clinical uses of topical antibiotics and antiseptics. In addition, we review the mechanisms of action of common topical agents and define the clinical and molecular epidemiology of antimicrobial resistance in these agents. Moreover, we review the potential use of newer and emerging agents, such as retapamulin and ebselen, and discuss the role of antiseptic agents in preventing bacterial skin infections. A comprehensive understanding of the clinical efficacy and drivers of resistance to topical agents will inform the optimal use of these agents to preserve their activity in the future.

Distribution of high-level mupirocin resistance among clinical MRSA

Mupirocin is a topical antibiotic for methicillin-resistant Staphylococcus aureus (MRSA) decolonization in hospital settings and nursing homes and is used as a highly effective antibiotic against MRSA. In this study, we aimed to evaluate the frequency of high-level mupirocin-resistant (HLMR) strains among the MRSA subtypes. A total of 188 clinical MRSA isolates were collected from 2011 to 2014, and their susceptibility to antimicrobial agents and vancomycin resistance was evaluated using disc diffusion method and micro-dilution method, respectively. Furthermore, the presence of mecA, SSCmec, mupA and mupB was assessed by PCR. All isolates were multi-drug resistant (MDR) but 2 strains (1.06%) were resistant to mupirocin. Minimum inhibitory concentration (MIC) of vancomycin for 8 strains (4.7%) was higher than 2 μg/ml. Of 188 isolates, 188 (100%), 64 (34.04%), 8 (4.3%), 150 (79.8%), 26 (13.8%), 2 (1.06) and 2 (1.06%) isolates possessed mecA, SCCmec types I, II, III, IV, mupA and mupB genes, respectively. Our data showed that despite infection control policy enforced by health care committee, the rate of mupirocin resistance among MRSA strains is continuously rising.

Genotypic and phenotypic characterization of methicillin-resistant Staphylococcus aureus (MRSA) clones with high-level mupirocin resistance

A high proportion of methicillin-resistant Staphylococcus aureus isolates recovered in one year period showed high-level mupirocin-resistance (HLMUPR-MRSA) in our environment (27.2%). HLMUPR-MRSA isolates were mainly collected from skin and soft tissue samples, and diabetes was the main related comorbidity condition. These isolates were more frequently found in vascular surgery. HLMUPR-MRSA was more resistant to aminoglycosides than mupirocin-susceptible MRSA, linked to the presence of bifunctional and/or nucleotidyltransferase enzymes with/without macrolide resistance associated with the msr(A) gene. Most of HLMUPR-MRSA isolates belonged to ST125/t067. Nine IS257-ileS2 amplification patterns (p3 was the most frequent) were observed in HLMUPR-MRSA isolates, suggesting the presence of several mupirocin-resistance-carrying plasmids in our environment and promoting the emergence of mupirocin resistance. The presence of the same IS257-ileS2 amplification pattern p3 in 65% of HLMUPR-MRSA, all of them ST125/t067, suggests a clonal spread in our hospital and community environment which could explain the high prevalence of HLMUPR-MRSA during the study period. An outbreak situation or an increase in mupirocin consumption was not observed.

High prevalence of mupirocin resistance in Staphylococcus aureus isolates from a pediatric population

Topical mupirocin is used widely to treat skin and soft tissue infections and to eradicate nasal carriage of methicillin-resistant Staphylococcus aureus (MRSA). Few studies to date have characterized the rates of S. aureus mupirocin resistance in pediatric populations. We retrospectively studied 358 unique S. aureus isolates obtained from 249 children seen in a predominantly outpatient setting by the Division of Pediatric Dermatology at a major academic center in New York City between 1 May 2012 and 17 September 2013. Mupirocin resistance rates and the associated risk factors were determined using a logistic regression analysis. In our patient population, 19.3% of patients had mupirocin-resistant S. aureus isolates at the time of their first culture, and 22.1% of patients with S. aureus infection had a mupirocin-resistant isolate at some time during the study period. Overall, 31.3% of all S. aureus isolates collected during the study period were resistant to mupirocin. Prior mupirocin use was strongly correlated (odds ratio [OR] = 26.5; P = <0.001) with mupirocin resistance. Additional risk factors for mupirocin resistance included methicillin resistance, atopic dermatitis (AD), epidermolysis bullosa (EB), immunosuppression, and residence in northern Manhattan and the Bronx. Resistance to mupirocin is widespread in children with dermatologic complaints in the New York City area, and given the strong association with mupirocin exposure, it is likely that mupirocin use contributes to the increased resistance. Routine mupirocin testing may be important for MRSA decolonization strategies or the treatment of minor skin infections in children.

Mupirocin/chlorexidine to prevent methicillin-resistant Staphylococcus aureus infections: post hoc analysis of a placebo-controlled, randomized trial using mupirocin/chlorhexidine and polymyxin/tobramycin for the prevention of acquired infections in intubated patients

PURPOSE

The reduction in acquired infections (AI) due to methicillin-resistant Staphylococcus aureus (MRSA) with the mupirocin/chlorhexidine (M/C) decontamination regimen has not been well studied in intubated patients. We performed post hoc analysis of a prior trial to assess the impact of M/C on MRSA AI and colonization.

METHODS

We conducted a multicenter, placebo-controlled, randomized, double-blind study with the primary aim to reduce all-cause AI. The two regimens used [topical polymyxin and tobramycin (P/T), nasal mupirocin with chlorhexidine body wash (M/C), or corresponding placebos for each regimen] were administered according to a 2 × 2 factorial design. Participants were intubated patients in the intensive care units of three French university hospitals. The patients enrolled in the study (n = 515) received either active P/T (n = 130), active M/C (n = 130), both active regimens (n = 129), or placebos only (n = 126) for the period of intubation and an additional 24 h. The incidence and incidence rates (per 1,000 study days) of MRSA AI were assessed. Due to the absence of a statistically significant interaction between the two regimens, analysis was performed at the margins by comparing all patient receiving M/C (n = 259) to all patients not receiving M/C (n = 256), and all patients receiving P/T (n = 259) to all patients not receiving P/T (n = 256).

RESULTS

Incidence [odds ratio (OR) 0.39, 95 % confidence interval (CI) (0.16-0.96), P = 0.04] and incidence rates [incidence rate ratio (IRR) 0.41, 95 % CI 0.17-0.97, P = 0.05] of MRSA AI were significantly lower with the use of M/C. We also observed an increase in the incidence (OR 2.50, 95 % CI 1.01-6.15, P = 0.05) and the incidence rate (IRR 2.90, 95 % CI 1.20-8.03, P = 0.03) of MRSA AI with the use of P/T.

CONCLUSION

Among our study cohort of intubated patients, the use of M/C significantly reduced MRSA AI.

Rapid PCR/ESI-MS-based molecular genotyping of Staphylococcus aureus from nasal swabs of emergency department patients

Background

A limitation of both culture-based and molecular methods of screening for staphylococcal infection is that current tests determine only the presence or absence of colonization with no information on the colonizing strain type. A technique that couples polymerase chain reaction to mass spectrometry (PCR/ESI-MS) has recently been developed and an assay validated to identify and genotype S. aureus and coagulase-negative staphylococci (CoNS).

Methods

This study was conducted to determine the rates, risk factors, and molecular genotypes of colonizing Staphylococcus aureus in adult patients presenting to an inner-city academic emergency department. Participants completed a structured questionnaire to assess hospital and community risks for infection with methicillin-resistant S. aureus (MRSA). Nasal swabs were analyzed by PCR/ESI-MS to identify and genotype S. aureus and CoNS.

Results

Of 200 patients evaluated, 59 were colonized with S. aureus; 27 of these were methicillin-resistant strains. Twenty-four of the 59 S. aureus carriers were co-colonized with a CoNS and 140 of the 200 patients were colonized exclusively with CoNS. The molecular genotypes of the 59 S. aureus strains were diverse; 21 unique molecular genotypes belonging to seven major clonal complexes were identified. Eighty-five of 200 patients carried strains with high-level mupirocin resistance. Of these eighty-five participants, 4 were colonized exclusively with S. aureus, 16 were co-colonized with S. aureus and CoNS, and 65 were colonized exclusively with CoNS.

Conclusion

The prevalence of S. aureus and methicillin-resistant S. aureus colonization in a random sample of patients seeking care in Emergency Department was 29.5% and 13.5%, respectively. A substantial fraction of the S. aureus-colonized patients were co-colonized with CoNS and high-level mupirocin-resistant CoNS. Determining the molecular genotype of S. aureus during intake screening may prove valuable in the future if certain molecular genotypes become associated with increased infection risk.

Molecular characterization of high-level mupirocin resistance in Staphylococcus pseudintermedius

The genetic analysis of high-level mupirocin resistance (Hi-Mup(r)) in a Staphylococcus pseudintermedius isolate from a dog is presented. The Hi-Mup(r) ileS2 gene flanked by a novel rearrangement of directly repeated insertion sequence IS257 elements was located, together with the aminoglycoside resistance aacA-aphD determinant, on a conjugative plasmid related to the pSK41/pGO1 family plasmids.

Virulence characteristic and MLST-agr genetic background of high-level mupirocin-resistant, MRSA isolates from Shanghai and Wenzhou, China

The emergence and prevalence of high-level mupirocin-resistant, methicillin-resistant Staphylococcus aureus (MuH MRSA) is challenging the eradication of MRSA nasal carriage and the treatment of skin and soft tissue infections. To understand the potentially pathogenetic capacity and the genetic basis of MuH MRSA, it is important to have a detailed knowledge of the molecular traits of this organism. Fifty three MuH MRSA isolates were gathered from Shanghai (28 isolates) and Wenzhou (25 isolates) in China. These isolates, consisting of 27 different PFGE-SCCmec-spa patterns, were examined by PCR for 35 virulence genes and further typed using agr (accessory gene regulator) typing and MLST (multilocus sequence typing). All 53 strains were positive for the genes hlg/hlg variant and icaD, and negative for seb, sed, see, seh, eta, etb, hld, cap-5, and ACME-arcA. Compared with Wenzhou isolates, Shanghai isolates were more likely to carry seg (P = 0.002) and several other genes which were not found in Wenzhou strains such as sec, sei, tst (P<0.001 each), and pvl (P = 0.012), and less likely to contain sea (P<0.001), cna (P = 0.031), and efb (P = 0.045). MLST and agr typing showed that ST239-agr1, ST5-agr1, and ST239-agr2 were the common lineages in MuH MRSA isolates from these two different regions. Our results indicated that MuH MRSA strains from two different geographic regions of China have differences in distribution of some virulence genes, while their major MLST-agr genetic backgrounds were accordant.

Complete nucleotide sequence and comparative analysis of pPR9, a 41.7-kilobase conjugative staphylococcal multiresistance plasmid conferring high-level mupirocin resistance

We have sequenced the conjugative plasmid pPR9, which carries the ileS2 gene, which had contributed to the dissemination of high-level mupirocin resistance at our institution. The plasmid backbone shows extensive genetic conservation with plasmids belonging to the pSK41/pGO1 family, but comparative analyses have revealed key differences that provide important insights into the evolution of these medically important plasmids and high-level mupirocin resistance in staphylococci and highlight the role of insertion sequence IS257 in these processes.

Resistance to and synthesis of the antibiotic mupirocin

Mupirocin, a polyketide antibiotic produced by Pseudomonas fluorescens, is used to control the carriage of methicillin-resistant Staphylococcus aureus on skin and in nasal passages as well as for various skin infections. Low-level resistance to the antibiotic arises by mutation of the mupirocin target, isoleucyl-tRNA synthetase, whereas high-level resistance is due to the presence of an isoleucyl-tRNA synthetase with many similarities to eukaryotic enzymes. Mupirocin biosynthesis is carried out by a combination of type I multifunctional polyketide synthases and tailoring enzymes encoded in a 75 kb gene cluster. Chemical synthesis has also been achieved. This knowledge should allow the synthesis of new and modified antibiotics for the future.

Genetic analysis of high-level mupirocin resistance in the ST80 clone of community-associated meticillin-resistant Staphylococcus aureus

Four community-associated meticillin-resistant Staphylococcus aureus (CA-MRSA) isolates expressing high-level mupirocin resistance (MIC >1024 mg l(-1)) were isolated from four sites of a diabetic patient and characterized for the genetic location of their resistance determinants and typed using PFGE, staphylococcal cassette chromosome mec (SCCmec), the coagulase gene and multilocus sequence typing to ascertain their relatedness. The presence of genes for resistance to high-level mupirocin (mupA), tetracycline (tetK) and fusidic acid (far1), Panton-Valentine leukocidin (PVL), accessory gene regulators (agr) and capsular polysaccharide (cap) were detected in PCR assays. The isolates were resistant to kanamycin, streptomycin, tetracycline, fusidic acid and cadmium acetate, and harboured mupA, tetK, far1, PVL, agr3 and cap8. They had identical PFGE patterns and coagulase gene type, possessed the type IV SCCmec element and belonged to sequence type 80 (ST80). However, they had three different plasmid profiles: (i) 28.0 and 26.0 kb; (ii) 28.0, 21.0 and 4.0 kb; and (iii) 41.0 and 4.0 kb. Genetic studies located the resistance to tetracycline, fusidic acid and cadmium acetate on the 28 kb plasmid and mupA on the related non-conjugative 26 and 21 kb plasmids. One of the 21 kb mupirocin-resistance plasmids was derived from the approximately 41 kb plasmid during transfer experiments. The emergence of high-level mupirocin resistance in the ST80-SCCmec IV MRSA clone demonstrates the increasing capacity of CA-MRSA clones to acquire resistance to multiple antibacterial agents. The presence of different plasmid profiles in genetically identical isolates creates difficulty in the interpretation of typing results and highlights the weakness of using plasmid analysis as the sole method for strain typing.

Mupirocin resistance among methicillin-resistant Staphylococcus aureus-colonized patients at admission to a tertiary care medical center

All patients admitted to our tertiary care hospital from 1 December 2007 to 10 June 2008 were screened for methicillin (meticillin)-resistant Staphylococcus aureus (MRSA) nasal colonization, and the isolates were tested for mupirocin susceptibility by using Etest. Mupirocin resistance (MR) was noted to occur in 3.4% of MRSA carriers, and high-level MR was noted to occur in 0.62% of carriers.

Prevenção de infecções de corrente sanguínea relacionadas a cateter em pacientes em hemodiálise

OBJETIVO: Realizar uma revisão sistemática sobre medidas padronizadas para prevenção de infecções relacionadas a cateter em pacientes em hemodiálise. MÉTODOS: Foi realizada uma revisão sobre a prevenção de infecções em hemodiálise nas bases de dados Medline, Embase, SciElo, Lilacs e Cochrane Library de estudos publicados entre os anos de 1990 e 2008. RESULTADOS: Foram encontrados 293 artigos e destes 12 foram incluídos no estudo. CONCLUSÃO: Foi evidenciada a importância da aplicação de um conjunto de medidas de controle de infecções pelos profissionais da saúde para prevenir a infecção nesta população de pacientes.

Mupirocin resistance in patients colonized with methicillin-resistant Staphylococcus aureus in a surgical intensive care unit

BACKGROUND

Nasal colonization with methicillin-resistant Staphylococcus aureus (MRSA) can be a precursor to serious infection, and decolonization with topical mupirocin has been studied as a means of preventing clinical infection. Mupirocin resistance in patients with MRSA has been reported, usually in the context of widespread mupirocin use.

METHODS

Patients admitted to a surgical intensive care unit (SICU) had nasal swab cultures for MRSA performed at admission, weekly, and at discharge in an active surveillance program. Collected MRSA isolates were tested for mupirocin resistance, and molecular analysis was performed. Clinical data on the characteristics and outcomes of the patients who stayed in the SICU for >48 h were collected prospectively.

RESULTS

Of the 302 MRSA isolates available for testing, 13.2% were resistant to mupirocin, with 8.6% having high-level resistance (minimum inhibitory concentration, >or=512 microg/mL) and 4.6% having low-level resistance (minimum inhibitory concentration, 8-256 microg/mL). Patients admitted to the SICU for >48 h who were colonized with mupirocin-resistant MRSA were more likely to have been admitted to our hospital during the previous year (P=.016), were older (P=.009), and had higher in-hospital mortality (16% vs. 33%; P=.027), compared with patients colonized with mupirocin-susceptible MRSA. Molecular analysis of the mupirocin-resistant isolates revealed that 72.5% of isolates contained staphylococcal cassette chromosome mec II. Repetitive sequence polymerase chain reaction typing revealed that high-level mupirocin resistance was present in multiple clonal groups. The rate of mupirocin use hospital-wide during the study period was 6.08 treatment-days per 1000 patient-days.

CONCLUSIONS

We documented a high rate of mupirocin resistance in MRSA isolates from SICU patients, despite low levels of in-hospital mupirocin use.

Treatment ofStaphylococcus aureusinfections: new issues, emerging therapies and future directions

Infections due to Staphylococcus aureus are a major cause of morbidity and mortality worldwide. Antimicrobial resistance in strains of S. aureus is a continually evolving problem, including widespread methicillin resistance in hospitals, increasing methicillin resistance in community strains, and the recent acquisition of glycopeptide resistance. New antimicrobials with activity against S. aureus have recently entered the market or are in the late stages of development. In addition, there has been significant interest in the development of novel and immune-based strategies for prevention or treatment of S. aureus infections. This review describes established and emerging therapies for S. aureus infections, and considers the safety profiles and likely impact on present treatment standards of novel agents either undergoing clinical development or emerging onto the market.