Background: Host- and pathogen-related factors associated with septic shock in pneumococcal pneumonia are not well defined. We aimed to identify risk factors for septic shock and to ascertain patient outcomes. Serotypes, genotypes, and antibiotic resistance of isolated strains were also analysed.
Methods: Observational analysis of a prospective cohort of nonseverely immunosuppressed hospitalised adults with pneumococcal pneumonia. Septic shock was defined as a systolic blood pressure of <90 mmHg and peripheral hypoperfusion with the need for vasopressors for >4 hrs after fluid replacement.
Results: We documented 1041 patients with pneumococcal pneumonia diagnosed by Gram stain and culture of appropriate samples and/or urine antigen test, of whom 114 (10.9%) had septic shock at admission. After adjustment, independent risk factors for shock were current tobacco smoking (odds ratio [OR], 2.11; 95% confidence interval [CI], 1.02-4.34; p=0.044), chronic corticosteroid therapy (OR, 4.45; 95% CI, 1.75-11.32; p=0.002), and serotype 3 (OR, 2.24; 95% CI, 1.12-4.475; p=0.022). No significant differences were found in genotypes and rates of antibiotic resistance. Compared with the remaining patients, patients with septic shock required mechanical ventilation more frequently (37% vs 4%; p<0.001) and had longer length of stay (11 vs 8 days; p<0.001). The early (10% vs 1%; p<0.001) and overall case-fatality rates (25% vs 5%; p<0.001) were higher in patients with shock.
Conclusions: Septic shock is a frequent complication of pneumococcal pneumonia and causes high morbidity and mortality. Current tobacco smoking, chronic corticosteroid therapy, and infection caused by serotype 3 are independent risk factors for this complication.