infectious diseases
Pneumococcal Infections
Introduction
Streptococcus pneumoniae(pneumococci) are gram-positive, alpha-hemolytic, aerobic, encapsulated diplococci. Pneumococcal infection is a major cause of otitis media, pneumonia, sepsis, meningitis, and death. Diagnosis is by Gram stain and culture. Treatment depends on the resistance profile and includes either a beta-lactam, a macrolide, a respiratory fluoroquinolone, a pleuromutilin, or sometimesvancomycin. Pneumococci are fastidious microorganisms that require catalase to grow on agar plates. In the laboratory, pneumococci are identified by Gram-positive lancet-shaped diplococci Catalase-negative Alpha-hemolysis on blood agar Sensitivity to optochin Lysis by bile salts Pneumococci commonly colonize the human respiratory tract, particularly in winter and early spring. Spread is via airborne droplets. True epidemics of pneumococcal infections are rare; however, some serotypes seem to be associated with outbreaks in certain populations or settings (eg, military, congregate settings, people who are homeless), particularly in crowded settings. 