Community-acquired pneumonia due to multidrug and non-multidrug resistant pseudomonas aeruginosa

Background: Pseudomonas aeruginosa is not a frequent pathogen in Community Acquired Pneumonia (CAP). However, in patients with severe CAP P. aeruginosa can be the etiology in 1.8% to 8.3% of patients, with a case-fatality rate of 50% to 100%. We describe the prevalence, clinical characteristics, outcomes and risk factors associated with CAP due to multidrug and non-multidrug resistant P. aeruginosa. Methods: Prospective observational study, including 2,023 consecutive adult CAP patients with definitive etiology. Results: P. aeruginosa was found in 77 (4%) of the 2,023 cases with microbial etiology. In 22 (32%) of the 68 cases of P. aeruginosa with antibiogram data, the isolates were multidrug- resistant (MDR). Inappropriate therapy was present in 49 (64%) cases of P. aeruginosa CAP, including 17/22 (77%) cases of MDR P. aeruginosa CAP. Male gender, chronic respiratory disease, C-reactive protein P. aeruginosa CAP. Prior antibiotic treatment was more frequent in MDR P. aeruginosa CAP compared with non-MDR P. aeruginosa (58% vs. 29%, p=0.029), and was the only risk factor associated with CAP due to MDR P. aeruginosa . In the multivariate analysis age ≥65 years, CAP due to P. aeruginosa , chronic liver disease, neurologic disease, nursing-home, criteria of ARDS, acute renal failure, ICU admission and inappropriate empiric treatment were the factors associated with 30- day mortality (Table 1). Conclusions: P. aeruginosa is an individual risk factor associated with mortality in CAP. The risk factors described can help clinicians to suspect P. aeruginosa and MDR P. aeruginosa.