Microbiology and outcomes of severe pneumonia in critically ill cancer patients

Introduction

Pneumonia is the most frequent types of infection in cancer patients. The presence of multiresistant pathogens (MR) is often associated with inadequate antimicrobial therapy. The aims of this study were to describe the microbiology and outcomes of cancer patients with severe pneumonia requiring ICU admission.

Methods

A secondary analysis of a prospective cohort study was performed from 2002 to 2011 at Instituto Nacional de Cancer and Hospital Sirio-Libanes, Brazil. Adult patients with a diagnosis of cancer with pneumonia (not acquired in the hospital setting) were evaluated at ICU admission. Demographic, clinical and laboratory data were collected during the first day in the ICU, severity scores, comorbidities, performance status, cancer-related data, microbiologic identification, empiric antibiotics and the adherence to treatment guidelines.

Results

A total of 268 patients were enrolled: 187 (69.8%) patients with solid tumors and 81 (30.2%) patients with hematological malignancies. In total, 167 (62.3%) patients had septic shock, and ICU and hospital mortality rates were 45.5% and 67.9%. Microbiological confirmation was present in 140 (52%) patients with 56% Gram-negative. The most frequent pathogens were methicillin-sensitive S. aureus (36 (26%)), P. aeruginosa (35 (25%)) and S. pneumoniae (16 (12%)). Low incidence of MR (16 (11.4%)) was observed. Adequate antibiotic therapy based on microbiological identification was prescribed in 120 (85.72%) patients. Adherence to ATS/IDSA guidelines was observed in 41 (15.3%) patients. There were no differences regarding ATS/IDSA guideline adherence (MR 3 (18.8%) vs. no MR 38 (15.1%), P = 0.719). We observed a trend towards higher hospital mortality in the MR patients (MR 14 (87.5%) vs. no MR 168 (66.7%), P = 0.101). In multivariate analysis, mechanical ventilation (OR 2.52 (1.19 to 5.32)), dialysis (3.86 (1.23 to 12.10)) and higher SAPS2 (OR per point 1.03 (1.01 to 1.05)) were associated with increased hospital mortality whereas successful noninvasive ventilation was associated with lower mortality (0.32 (0.13 to 0.77)). MR were forced into MV analysis but were not associated with outcomes.

Conclusion

Severe pneumonia in cancer patients presents high hospital mortality, with particular clinical and microbiology features. Despite low adherence to ATS/IDSA guidelines, antibiotic therapy was adequate in most of patients following local guidelines based on local bacterial profiles. Further investigation is needed to clarify the impact of MRs in clinical outcomes of cancer patients with severe pneumonia.