The gram-positive coccus Streptococcus pneumoniae.
Person to person through close contact via respiratory droplets.
Streptococcus pneumoniae is the most common cause of community-acquired pneumonia worldwide. The prevalence is higher in developing than in industrialized countries. Risk is highest in young children, the elderly, and those with chronic illnesses or immune suppression.
Pneumococcal pneumonia classically presents with sudden onset of fever and malaise, cough, pleuritic chest pain, or purulent or blood-tinged sputum. In the elderly, fever, shortness of breath, or altered mental status may be initial symptoms. Pneumococcal meningitis may present as a stiff neck, headache, lethargy, or seizures.
Isolation from blood or cerebrospinal fluid, but most patients do not have detectable bacteremia. Pneumococcal urine antigen test may be useful but is not routinely recommended for diagnosis, as per the Infectious Diseases Society of America and American Thoracic Society guidelines (www.idsociety.org). Infection can be suspected if a sputum specimen contains gram-positive diplococci, polymorphonuclear leukocytes, and few epithelial cells. High white blood cell counts should raise suspicion for bacterial infection.
Therapy depends on the syndrome, but patients who present with community-acquired pneumonia should be empirically treated for pneumococcal infection. Many strains are resistant to penicillin, cephalosporins, and macrolides. In the United States and other countries where β-lactam resistance is common, the initial regimen for pneumococcal meningitis might include vancomycin or a fluoroquinolone, plus a third-generation cephalosporin.
The 13-valent pneumococcal conjugate vaccine (PCV13) is recommended for all children aged <5 years and children aged <72 months with chronic medical conditions; the vaccine is also recommended for children aged <18 years with immunocompromising conditions. A 23-valent pneumococcal polysaccharide vaccine (PPSV23) is recommended for adults aged ≥65 years and people aged 2–64 years with underlying medical conditions. Adults with immunocompromising conditions, functional or anatomic asplenia, cerebrospinal fluid leaks, or cochlear implants should receive PCV13 followed by PPSV23. See www.cdc.gov/vaccines/hcp/acip-recs/vacc-specific/pneumo.html .
CDC. Licensure of a 13-valent pneumococcal conjugate vaccine (PCV13) and recommendations for use among children—Advisory Committee on Immunization Practices (ACIP), 2010. MMWR Morb Mortal Wkly Rep. 2010 Mar 12;59(9):258–61.
CDC. Updated recommendations for prevention of invasive pneumococcal disease among adults using the 23-valent pneumococcal polysaccharide vaccine (PPSV23). MMWR Morb Mortal Wkly Rep. 2010;59(34):1102–6.
CDC. Use of 13-valent pneumococcal conjugate vaccine and 23-valent pneumococcal polysaccharide vaccine among children aged 6–18 years with immunocompromising conditions: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep. 2013 June 28; 62(25):521–4.
CDC. Use of 13-valent pneumococcal conjugate vaccine and 23-valent pneumococcal polysaccharide vaccine for adults with immunocompromising conditions: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Morb Mortal Wkly Rep. 2012;61(40):816–9.
World Health Organization. Pneumococcal vaccines WHO position paper—2012—Recommendations. Vaccine. 2012;30(32):4717–8.