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Prognostic factors of severe community-acquired staphylococcal pneumonia in France
Yves Gillet1,2,3, Anne Tristan2,3,4, Jean-Philippe Rasigade2,3,4
1Paediatric Emergency and Intensive Care Unit, Hospices Civils de Lyon, Lyon, France.
Insights
Panton-Valentine leukocidin (PVL) causes severe staphylococcal pneumonia in children and adults. PVL is linked to staphylococcal pleuropneumonia in toddlers and increases mortality risk in older patients with severe community-acquired pneumonia.
Area of Science:
- Infectious Diseases
- Microbiology
- Critical Care Medicine
Background:
- Staphylococcus aureus is a significant cause of severe community-acquired pneumonia (CAP).
- Specific forms include staphylococcal pleuropneumonia in children and necrotizing pneumonia in adults.
- The roles of methicillin resistance and Panton-Valentine leukocidin (PVL) in severe CAP outcomes are not fully understood.
Purpose of the Study:
- To investigate the risk factors for mortality in severe staphylococcal CAP.
- To assess the independent roles of PVL, methicillin resistance, and S. aureus genetic lineage in severe CAP outcomes.
Main Methods:
- A prospective multicenter cohort study was conducted in French intensive care units from 2011 to 2016.
- Included 163 patients with severe staphylococcal CAP, analyzing risk factors for mortality.
- Utilized univariate and multivariable Cox and LASSO regression analyses.
Main Results:
- Of 163 patients, 85 (52.1%) had PVL-positive CAP. In patients under 3 years, 19 of 20 (95%) had PVL-positive CAP, presenting as staphylococcal pleuropneumonia with lower mortality (15%) compared to older patients (47%).
- In older patients, PVL-positivity (HR 1.81) and methicillin resistance (HR 2.37) independently predicted mortality.
- S. aureus genetic lineage and other virulence factors did not independently predict mortality in older patients.
Conclusions:
- PVL is associated with staphylococcal pleuropneumonia in young children.
- PVL is an independent risk factor for mortality in older patients with severe CAP.
- Methicillin resistance also independently predicts mortality in older patients with severe CAP.
Purpose:
Staphylococcus aureus causes severe forms of community-acquired pneumonia (CAP), namely staphylococcal pleuropneumonia in young children and staphylococcal necrotising pneumonia in older patients. Methicillin resistance and the Panton-Valentine leukocidin (PVL) toxin, as well as less specific factors, have been associated with poor outcome in severe CAP, but their roles are unclear.
Methods:
A prospective multicentre cohort study of severe staphylococcal CAP was conducted in 77 paediatric and adult intensive care units in France between January 2011 and December 2016. After age-clustering, risk factors for mortality, including pre-existing conditions, clinical presentation, laboratory features, strain genetic lineage, PVL, other virulence factors and methicillin resistance were assessed using univariate and multivariable Cox and LASSO (least absolute shrinkage and selection operator) regressions.
Results:
Out of 163 included patients, aged 1 month to 87 years, 85 (52.1%) had PVL-positive CAP; there were 20 (12.3%) patients aged <3 years (hereafter "toddlers"), among whom 19 (95%) had PVL-positive CAP. The features of PVL-positive CAP in toddlers matched with the historical description of staphylococcal pleuropneumonia, with a lower mortality (three (15%) out of 19) compared to PVL-positive CAP in older patients (31 (47%) out of 66). Mortality in older patients was predicted by PVL-positivity (hazard ratio (HR) 1.81, 95% CI 1.03-3.17) and methicillin resistance (HR 2.37, 95% CI 1.29-4.34) independently from S. aureus lineages and the presence of other determinants of virulence.
Conclusion:
PVL was associated with staphylococcal pleuropneumonia in toddlers and was a risk factor for mortality in older patients with severe CAP, independently of methicillin resistance, S. aureus genetic background and other virulence factors.
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