Pulmonary damage and bacterial load in assessment of the efficacy of simulated human treatment-like amoxicillin (2,000 milligrams) therapy of experimental pneumococcal pneumonia caused by strains for which amoxicillin MICs differ

Delay in antibiotic therapy results in fatal disease outcome in murine pneumococcal pneumonia

BACKGROUND

Community-acquired pneumonia (CAP) remains a major cause of death worldwide. Mechanisms underlying the detrimental outcome despite adequate antibiotic therapy and comorbidity management are still not fully understood.

METHODS

To model timely versus delayed antibiotic therapy in patients, mice with pneumococcal pneumonia received ampicillin twice a day starting early (24 h) or late (48 h) after infection. Clinical readouts and local and systemic inflammatory mediators after early and late antibiotic intervention were examined.

RESULTS

Early antibiotic intervention rescued mice, limited clinical symptoms and restored fitness, whereas delayed therapy resulted in high mortality rates. Recruitment of innate immune cells remained unaffected by antibiotic therapy. However, both early and late antibiotic intervention dampened local levels of inflammatory mediators in the alveolar spaces. Early treatment protected from barrier breakdown, and reduced levels of vascular endothelial growth factor (VEGF) and perivascular and alveolar edema formation. In contrast, at 48 h post infection, increased pulmonary leakage was apparent and not reversed by late antibiotic treatment. Concurrently, levels of VEGF remained high and no beneficial effect on edema formation was evident despite therapy. Moreover, early but not late treatment protected mice from a vast systemic inflammatory response.

CONCLUSIONS

Our data show that only early antibiotic therapy, administered prior to breakdown of the alveolar-capillary barrier and systemic inflammation, led to restored fitness and rescued mice from fatal streptococcal pneumonia. The findings highlight the importance of identifying CAP patients prior to lung barrier failure and systemic inflammation and of handling CAP as a medical emergency.

Risks of nonsteroidal antiinflammatory drugs in undiagnosed intensive care unit pneumococcal pneumonia: younger and more severely affected patients

PURPOSE

The purpose of this study is to investigate whether exposure to nonsteroidal antiinflammatory drugs (NSAIDs) at the early stage of severe pneumococcal community-acquired pneumonia (CAP) requiring intensive care unit (ICU) admission may affect its presentation and outcome.

MATERIAL AND METHODS

Medical records of ICU adult patients (12-year period) with a pneumococcal CAP diagnosis were retrospectively analyzed according to previous NSAID exposure.

RESULTS

One hundred six confirmed pneumococcal CAP were identified, 20 received NSAIDs within 4 (2-6) days before admission. Nonsteroidal antiinflammatory drug-exposed patients were younger (43.3 vs 62.2 years; P < .0001), had less frequently at least one chronic comorbid condition (40% vs 75%; P = .003), had more often complicated pleural effusions (20% vs 2.3%; P = .01), and more frequent pleuropulmonary complications (odds ratio: 5.75 [1.97-16.76]). Nonsteroidal antiinflammatory drug patients required more often noninvasive ventilatory support (25% vs 4.6%; P = .003). Intensive care unit length of stay and mortality were similar.

CONCLUSIONS

We report as severe pneumococcal pneumonia in young and healthy patients exposed to NSAIDs as in older, more comorbid, and nonexposed ones. Nonsteroidal antiinflammatory drug use may mask initial symptoms and delay antimicrobial therapy, thus predisposing to worse outcomes.