NAME: Streptococcus pneumoniae
SYNONYM OR CROSS REFERENCE: Pneumococcus, diplococcus, pneumococcal pneumonia, bacteremia, acute sinusitis, acute otitis, meningitis.
CHARACTERISTICS: S. pneumoniae is of the Streptococcaceae family. The gram-positive, oval/lancet-shaped cocci are often arranged in pairs, known as a diplococcus, or can be present in short chains Footnote 1. There are around 90 serotypes and its surface capsule, which is the distinguishing trait of the pneumococcus and is the major virulent factor, holds a complex mosaic of monosacharides, oligosaccharides, and other polymer components that are of high-molecular weight Footnote 2. Culture grows on blood agar, where it forms round facultative anaerobic colonies surrounded by α-hemolysis Footnote 3.
PATHOGENICITY/TOXICITY: S. pneumoniae colonizes in the mucosal surfaces of the nasopharynx and upper respiratory airway, and symptoms of inflammation appear as the bacteria migrate into the sterile parts of the airway Footnote 4. It is the most common etiological agent of community-acquired pneumonia and otitis media, and the second most prevalent cause of bacterial meningitis in Israel (Neisseria meningitidis being the first) Footnote 1. Early symptoms include shaking chills and high fever, and coughs producing pink to rusty coloured sputum Footnote 2. If left untreated, sustained fever and pleuritic pain will develop, as well as sinusitis, endocarditis, arthritis, and peritonitis. When pneumococci migrate to the lungs, they can cause pneumonia, or can enter the blood stream and cause bacteremia or septicemia. Uncontrolled colonization of S. pneumonia in the lung, meninges, or middle ear will cause pneumococcal lysis, which can trigger inflammation. Mortality rate of pneumococcal pneumonia is 5 – 10% despite antimicrobial treatment, a higher mortality rate as been observed in patients with pneumococcal bacteremia, as it has been approximately 25 – 29% in the past four decades. S pneumoniae infection is an important cause of bacterial co-infection in patients with influenza and can increase the morbidity and mortality in these patients.
EPIDEMIOLOGY: Worldwide distribution. Incidence of infection is highest in people under 2 years of age or over 60 years of age, or in people afflicted by alcoholism, diabetes mellitus, chronic renal disease, or asplenia Footnote 2. Globally, it causes approximately 1.2 million infant deaths annually, and its prevalence is especially high in regions of widespread HIV-1 infection Footnote 4.
HOST RANGE: Humans, mice, rats, guinea pigs, chimpanzees, rhesus monkeys, and mammals that live in association with humans Footnote 4.
INFECTIOUS DOSE: Unknown for humans. Mice developed sepsis or pneumonia when infected with 107 or 108 cfu, and after infection with 104 bacteria, S. pneumoniae are able to cross the blood-brain barrier Footnote 5.
MODE OF TRANSMISSION: Infectious cells can be disseminated via microaerosol droplets created by coughing or sneezing, or person-person oral contact Footnote 2. Transmission is common, but infection is infrequent as healthy individuals carry S. pneumoniae in the nasopharyngeal region without any presence of infection Footnote 6.
INCUBATION PERIOD: Not well determined as they are present in the nasopharynx of healthy individuals Footnote 1, but it has been speculated to be about 1 – 3 days.
COMMUNICABILITY: Transmitted between humans by aerosol pathways via coughing or sneezing Footnote 2.
RESERVOIR: Humans, bacteria are often located in the upper respiratory tracts of healthy individuals where they colonize and multiply Footnote 1.
DRUG SUSCEPTIBILITY: Susceptible to penicillin, tetracycline, cefotaxime, levofloxacin, erythromycin, and fluoroquinolones, especially moxifloxacin and gatifloxacin Footnote 7, Footnote 8. The bacteria display full susceptibility to telithromycin, vancomycin, and linezolid Footnote 9.
DRUG RESISTANCE: Multi-drug resistant S. pneumoniae is emerging. It displays high resistance to penicillin, as well as to erythromycin, cefotaxime, levofloxacin, tetracycline, TMP/SMX, β-lactam agents, macrolides, chloramphenicol, and ceftriaxone Footnote 7, Footnote 10, with fluoroquinolone-resistant strains being resistant to ciprofloxacin and levofloxacin treatments Footnote 11.
SUSCEPTIBILITY TO DISINFECTANTS: Exposure to 0.5% glutaraldehyde, 1% sodium hypochlorite, iodines, 70% ethanol, and formaldehyde (effective at higher temperatures than 20˚C) have been shown to disinfect S. pneumonia Footnote 12, Footnote 13.
PHYSICAL INACTIVATION: Cells can be inactivated by heat suspension in a water bath at 56˚C for 30 minutes Footnote 14,
SURVIVAL OUTSIDE HOST: Streptococcus spp. can survive in dental plaque for up to 7 days, in dust for up to 20 days, on glass for 1 – 11 days, and up to 180 days in frozen fish Footnote 15-Footnote 17.
SURVEILLANCE: Monitor for symptoms. Gram-negative stains or bacteriology studies of direct smears from nasal fluid, fluid from lesions, or areas of inflammation can be used to detect symptomatic or asymptomatic infections Footnote 18. ELISA, PCR fingerprinting analysis, and radiography techniques are also useful for diagnosis.
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: Administer appropriate drug treatment. Inflammation caused by pneumococcal lysis makes the treatment of pneumococcal diseases less effective with antibiotics alone, and even highly effective bactericidals such as β-lactam may actually enhance the harmful effects of the disease in some cases Footnote 1.
IMMUNIZATION: Recent widespread use of a pneumococcal capsular polysaccharide (CPS) conjugate vaccine reduces the incidences of carriage of the bacteria in children, and, as a result, herd immunity has also been observed Footnote 4. Protection, however, is serotype-specific, but development of promising vaccines are focusing on viral pneumococcal proteins that are common to all serotypes. Pneumococcal vaccination is recommended in Canada for infants less than 2 years of age, adults over 65 years and others at high risk of invasive pneumococcal disease Footnote 19.
PROPHYLAXIS: Currently available vaccines are the pneumococcal conjugate vaccine (PCV7) which is effective against 7 serotypes, and it has been shown to be effective for children less than 2 years of age Footnote 20. The pneumococcal polysaccharide vaccine (PPV23) is effective against 23 serotypes Footnote 21.
LABORATORY-ACQUIRED INFECTIONS: There have been 78 reported cases as of 1999 Footnote 22.
PRIMARY HAZARDS: Inhalation of aerosols containing bacterial cells, accidental parenteral inoculation, direct mucous-to-person contact Footnote 2.
SPECIAL HAZARDS: Bite-wounds from animals infected with Streptococcus spp.
RISK GROUP CLASSIFICATION: Risk group 2.
CONTAINMENT REQUIREMENTS: Containment level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures Footnote 24.
PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes Footnote 24.
OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities Footnote 24.
SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up.
DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism before disposing by autoclave, chemical disinfection, gamma irradiation, or incineration.Footnote 24.
STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labelled
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
UPDATED: December 2011
PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada
Although the information, opinions and recommendations contained in this Pathogen Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Public Health Agency of Canada, 2011