Healthcare-associated pneumonia: a never-ending story

Most studies observed statistically significant differences in terms of mortality between patients with CAP and HCAP. Some authors attributed this increased mortality to differences existing in terms of median age or presence of comorbidities, 18 but other studies confirmed that patients with HCAP had a worse prognosis independent of differences in age, comorbidities, or immunosuppression. 6 A critical disparity appears to be the greater administration of inappropriate initial antimicrobial therapy in patients with HCAP compared to those with CAP, as a result of a higher incidence of infection with antibiotic-resistant pathogens among patients with HCAP. 19,20 Pathogens associated with inappropriate antibiotic treatment in patients with HCAP are most often MRSA, P. aeruginosa or other nonfermenting Gram-negative rods, and antibiotic-resistant Enterobacteriaceae. In a Japanese study, HCAP patients with potentially drugresistant pathogens (including MRSA, P. aeruginosa, and ESBL-producing Enterobac teriaceae) had a risk ratio of 14.0 with respect to inappropriate initial antibiotic treatment. Of importance, a comparison between these studies is very difficult, due to methodological differences and number of patients enrolled. For this reason, recent studies have been published in order to provide scores based on epidemiological criteria and clinical clues for an early identification of patients with pneumonia due to MDR pathogens (Table 1). 21-25