GLIMP Study: Worldwide Prevalence and Risk Factors for MRSA Pneumonia

Introduction

Community-acquired pneumonia is the most common lower respiratory tract infection and is the leading cause of death due to infection, worldwide. The increasing prevalence of methicillin-resistant S aureus (MRSA) among the patients with community-acquired pneumonia has been emphasised by previous scientific literature and clinical guidelines. MRSA has become of particular concern in the management of lower respiratory tract infections. However, data on the worldwide prevalence and risk factors for MRSA pneumonia is limited.

Aim

To determine the point prevalence and specific risk factors associated with MRSA infection in hospitalised patients with community-acquired pneumonia.

Patient Profile

• N=3702
• Adult (>18 years old) patients in hospital with a diagnosis of community-acquired pneumonia.
• Community-acquired pneumonia was defined by evidence of new pulmonary infiltrates on thoracic imaging (chest radiograph, CT, or ultrasound) during the first 48 h in the hospital and at least one of the following criteria:
  • new or increased cough with or without sputum production or with purulent respiratory secretions;
  • fever (documented rectal or oral temperature ≥37·8°C) or hypothermia (documented rectal or oral temperature <36^oC); and evidence of systemic inflammation, such as abnormal white blood cell count (leucocytosis [>10 000 cells per mL], leucopenia [<4000 cells per mL], or bandaemia [>10%]) and increased C-reactive protein or procalcitonin concentrations above the local upper limit of normal

Method

• The Global Initiative for MRSA Pneumonia (GLIMP) study
• International
• Multicentre
• Observational cohort study
• Conducted in 222 hospitals in 54 countries
• Cultures were done from blood samples (n=2211 [69%]) and respiratory samples (sputum [n=1630; 51%], bronchoalveolar lavage [n=311 [10%], endotracheal aspirate (n=274 [9%]), and pleural fluid cultures (n=117 [4%]
• MRSA prevalence was calculated using MRSA isolates from the study cohort with bacteriological testing done during the first 24 h of hospital admission.

Results

• The overall prevalence of confirmed MRSA pneumonia was 3·0% (n=95), with differing prevalence between continents and countries.
• Respiratory samples (n=67; 71%) were the most common culture confirmations of MRSA pneumonia (sputum [n=30; 32%], endotracheal aspirate [n=21; 22%], broncho alveolar lavage [n=15; 16%], and pleural fluid culture [n=1; 1%]), followed by blood cultures (n=28; 29%).
• The only country with a significantly higher prevalence of MRSA community-acquired pneumonia than other participating countries was the USA.
• The only country with a significantly lower prevalence of MRSA community-acquired pneumonia was Spain.
• Three risk factors were independently associated with MRSA pneumonia:
  • previous MRSA infection or colonisation (odds ratio 6·21)
  • recurrent skin infections (2·87)
  • severe pneumonia disease (2·39)

Conclusion

• The worldwide prevalence of MRSA in community-dwelling patients hospitalised with pneumonia is lower than has been previously estimated.
• The specific risk factors for MRSA community-acquired pneumonia identified in this study might help to assist clinicians when deciding to initiate empiric antibiotic coverage against MRSA
• Finally, the authors suggested that recommendations for appropriate antibiotic use should be driven by local MRSA prevalence rates in the community before adopting a generic “one size fits all” recommendation.

Lancet Infect Dis 2016; 16: 1364–76