Community-acquired pneumonia in immunocompromised older patients: incidence, causative organisms and outcome

Abstract

The number of elderly patients in the community with immunosuppressive conditions has increased progressively over recent decades. We sought to determine the incidence, causative organisms and outcome of community-acquired pneumonia (CAP) occurring in immunocompromised older patients. We prospectively compared cases of CAP in immunocompromised and non-immunocompromised patients admitted to five public hospitals in three Spanish regions. Of 320 cases studied, 115 (36%) occurred in immunocompromised patients, including: solid or hematological malignancy (97), corticosteroids or other immunosuppressive drugs (44), solid organ or stem cell transplant (five), and other conditions (eight). The etiology was established in 44% of immunocompromised patients vs. 32% of non-immunocompromised patients (p 0.03). Streptococcus pneumoniae was the most common causative organism in both groups (29% vs. 21%; p 0.08), followed by Legionella pneumophila (3% vs. 6%; p 0.01). Gram-negative bacilli were more frequent among immunocompromised patients (5% vs. 0.5%; p <0.01), particularly Pseudomonas aeruginosa (3% vs. 0%; p 0.04). Nocardiosis was only observed in immunocompromised patients (two cases). Bacteremia occurred similarly in the two groups. No significant differences were found with respect to ICU admission (8%, in both groups) or the length of stay (12.5 vs. 10.4 days). The early (<48 h) (3.5 vs. 0.5%; p 0.04) and overall case-fatality rates (12% vs. 3%; p <0.01) were higher in immunocompromised patients. In conclusion, a substantial number of older patients hospitalized for CAP are immunocompromised. Although relatively uncommon, CAP due to gram-negative bacilli, including P. aeruginosa, is more frequent among these patients. CAP occurring in immunocompromised patients causes significant morbidity and mortality.

The management of community-acquired pneumonia in the elderly

“…Moreover, comorbidities, such as COPD and bronchiectasis, can alter the defensive mechanisms of the lung, diminishing muco-ciliary clearance. In a recent study, Sousa and colleagues compared the causative agent of pneumonia in 115 immunocompromised vs. non-immunocompromised elderly patients [59]. S. pneumoniae was the most common causative agent in both groups, but Gram-negative bacilli were more frequent among immunocompromised patients, particularly, P. aeruginosa and Nocardia spp.…”

The Pseudomonas aeruginosa AlgZR two-component system coordinates multiple phenotypes

“…P. aeruginosa is the predominant bacterial pathogen in cystic fibrosis (CF) patients, where colonization by P. aeruginosa in the CF lung is linked to a worsening disease prognosis (Henry et al, 1982, 1992; Nixon et al, 2001). It is also a significant cause of hospital-acquired infections (Almirante et al, 2012; Orsi et al, 2012; Horcajada et al, 2013; Khawaja et al, 2013; Simonetti et al, 2013), particularly in burn-wounds (Regules et al, 2008; Belba et al, 2013), and immunocompromised individuals (Gomes et al, 2011; Papagheorghe, 2012; Sousa et al, 2013). P. aeruginosa is able to form multiple types of biofilms, which allow them to persistently colonize a variety of surfaces, thereby making their eradication extremely challenging.…”

Effects of Inhaled Corticosteroids on Pneumonia Severity and Antimicrobial Resistance

“…9,13–15 Although recent and numerous randomized trials and meta-analyses have evaluated the impact of ICS on pneumonia-related or overall mortality, 6–15 few data are available regarding the association of prior ICS with the severity of illness at admission or its impact on antimicrobial resistance. Although chronic systemic corticosteroids use has been associated with higher risk of opportunistic infections 16–18 and potentially highly drug-resistant pathogens, 19,20 these associations are not clear in patients treated with ICS. Therefore, our aim was to investigate the association of prior out-patient ICS use with severity of illness and antimicrobial resistance in hospitalized patients with CAP at the time of admission.…”