Andrea Morotti, MD
Pneumonia is a common medical complication in subjects suffering acute stroke and is independently associated with poor functional outcome. In this paper, Dr. Kishore and colleagues described the microbiological etiology of pneumonia in stroke patients through a systematic review of the available literature.
A total of 7968 subjects included in 15 studies were analyzed. The authors reported notable variability in the rate of pneumonia (2% to 63%), and the majority of patients (78%) developed this complication within one week from stroke onset. Sputum culture was the most common method to obtain biological samples for culture, whereas a minority of patients underwent tracheal aspirate or blood culture (15% and 20%, respectively). There was also significant heterogeneity in the prevalence of positive cultures (15% to 88%), and the following pathogens were more commonly identified: Klebsiella pneumoniae (12.8%), Escherichia coli (9%), Staphylococcus aureus (10.1%). Interestingly, Streptococcus Pneumoniae was identified in only 3.5% of cases.
Despite some relevant limitations (retrospective analysis and heterogeneous characteristics of the included subjects), this manuscript provided useful data for clinical practice and future clinical trials, and highlighted a major knowledge gap in the biology of pneumonia complicating acute stroke. Another major limitation is the lack of data on dysphagia and aspiration pneumonia. It would be of great interest to explore whether patients with aspiration pneumonia have a specific microbiological profile.
Clinicians prescribing empirical antibiotic treatment should consider that Gram-negative bacilli and Gram-positive cocci accounted for more than half of the isolated pathogens. A better knowledge of the microbiological profile of stroke-associated pneumonia may also provide helpful data for preventive antibiotic treatment in the setting of randomized clinical trials.
Standardization of microbiological samples collection and guidelines for antibiotic treatment of pneumonia in subjects with stroke are highly desired.