Methicillin-resistant Staphylococcus aureus pneumonia in adults

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) has become one of the leading etiologies of nosocomial pneumonia as a result of an increase in staphylococcal infections caused by methicillin-resistant strains paired with extended ventilatory support of critically, and often, chronically ill patients. The prevalence of community-acquired MRSA pneumonia, which historically affects younger patients and is often preceded by an influenza-like illness, is also increasing. A high index of suspicion and early initiation of appropriate antibiotics are key factors for the successful treatment of this disease. Even with early diagnosis and appropriate treatment, MRSA pneumonia still carries an unacceptably high mortality rate. This article will review historical differences between hospital-acquired and community-acquired MRSA pneumonia, as well as, clinical features of, diagnosis and treatment of MRSA pneumonia.

Keywords::

• community-acquired pneumonia
• hospital-acquired pneumonia
• linezolid
• methicillin-resistant Staphylococcus aureus
• Panton–Valentine leukocidin
• vancomycin
• ventilator-associated pneumonia

Financial & competing interests disclosure

G Colice is a consultant/speaker/advisory board member to Pearl, Teva, MedImmune, Mylan, and Alitair. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of hospital-acquired and community-acquired pneumonia.

• Exposure to the healthcare environment has little predictive value for differentiating between infections due to traditional hospital-acquired isolates from those caused by community-acquired MRSA.

• Hospital-acquired disease occurs more frequently in elderly patients with underlying comorbidities, while community-acquired disease tends to occur more frequently in a younger population and is often associated with an influenza-like prodrome.

• The role of Panton-Valentine leukocidin in community-acquired MRSA pneumonia is still not entirely clear.

• Establishing a diagnosis of MRSA pneumonia is fraught with the same difficulties as all other pneumonia.

• The clinical failure rate for vancomycin remains unacceptably high and linezolid may offer a better treatment option, although further studies are needed.

• Cost–effective rapid diagnostic tests that allow earlier diagnosis of MRSA are needed.

• Future studies will likely continue to focus on antimicrobial peptides that alter the inflammatory response, monoclonal antibodies against specific staphylococcal toxins and vaccine development.

Notes