New modalities in treating pneumococcal pneumonia

The impact of statin and macrolide use on early survival in patients with pneumococcal pneumonia

BACKGROUND

Mortality in pneumococcal pneumonia remains high despite early antibiotic eradication of bacteria. Most deaths occur within the first week, the time of peak inflammatory responses. Statins and macrolides have broad immunosuppressive activity; their impact, separately and together, on survival in patients with pneumococcal pneumonia was evaluated.

METHODS

All patients with pneumococcal pneumonia seen at a single medical center from 2000 through 2010 were included in this retrospective cohort study. A multivariate-adjusted Cox proportional hazard model was used to evaluate survival.

RESULTS

Of 347 patients with pneumococcal pneumonia, 90 (26%) were taking a statin at presentation and 126 (36%) were started on treatment with a macrolide. Thirty-two (9%) statin users were treated with a macrolide. Statin users were older than non-statin users, with a higher prevalence of diabetes, coronary artery disease and chronic kidney disease and a lower prevalence of alcohol consumption and liver disease. Statin users had higher mean Pneumonia Patient Outcomes Research Team scores. Patients treated with a macrolide were not different from those who received other antibiotics. The risk of mortality among statin users was reduced at 7, 14, 20 and 30 days after admission. Mortality was not reduced in patients treated with a macrolide or with a macrolide plus a statin compared with those who did not receive a macrolide.

CONCLUSIONS

Patients who are receiving statins at the time of admission for pneumococcal pneumonia have better clinical outcomes than those who are not. Treatment with a macrolide does not appear to confer a survival benefit.

Association between statins and infections after coronary artery bypass grafting

BACKGROUND

We determined whether pre-operative statin therapy is associated with a decrease in the incidence of infections after coronary artery bypass grafting (CABG).

METHODS

A retrospective cohort study of 6253 patients undergoing isolated CABG, from the Texas Heart Institute Database from January 1, 2000 to December 31, 2010 (3869 receiving statins and 2384 not receiving statins) was conducted. Primary outcome was the development of any postoperative infection (composite of deep-sternal wound infection, leg harvest-site infection, pneumonia, or sepsis) after CABG. Secondary outcome was the association between pre-operative statin use and individual incidence of each aforementioned infection. Logistic regression analyses were performed.

RESULTS

Incidence of any postoperative infection in patients who received statins pre-operatively was 6.5% compared to 8.3% in patients who did not receive statins. Pre-operative statin therapy was associated with a significant reduction in the primary outcome (odds ratio (OR) 0.74, 95% confidence interval (CI) 0.60-0.90) in adjusted models. Among individual secondary outcomes, pre-operative statin therapy was associated with a reduced incidence of sternal wound infections (2.5% vs. 3.2%, OR 0.6, 95% CI 0.5-0.8) and leg harvest site infections (0.6% vs. 1.3%, OR 0.46, 95% CI 0.2-0.8). Pre-operative statin therapy was not associated with a reduced incidence of pneumonia or sepsis.

CONCLUSION

Pre-operative statin use is associated with a decrease in overall incidence of post-operative infections after CABG. We propose immunomodulatory effects of statins leading to a dampening of inflammatory cascade as the cause of our findings.

Modulation of bacterial pathogenesis by oppressive aging factors: insights into host-pneumococcal interaction strategies

Streptococcus pneumonia, (Spn, the pneumococcus), is the leading cause of community-acquired pneumonia (CAP) and is responsible for 15–40% deaths in the elderly worldwide. A primed inflammatory status is a significant risk factor for the increased severity of infectious diseases among the elderly (≥65 years of age). Studies have shown that expression of host receptors that the pneumococci bind to invade the tissues are increased thereby increasing the susceptibility to pneumococcal challenge in aged mice. Cellular senescence, an age-related phenomenon that leads to cell cycle arrest may also contribute to increased inflammation in aged mice. Evidence of cellular senescence in aged lungs of humans and mice adds credits to the concept of inflammaging and enhanced bacterial ligands expression during aging. Furthermore, cell senescence has been shown to occur in age-associated lung pathologies such as idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) that may predispose the elderly to pathogenic assaults, including S. pneumoniae. This review highlights the aspects of: chronic inflammation in the aged population; contribution of cellular senescence to age-associated inflammation and their impact on host receptor expression; and, increased susceptibility of fibrosis and emphysematous lesions-bearing lungs to microbial infections.