Pneumococcal disease, caused by streptococcus pneumoniae bacteria (pneumococcus), is a series of infections that can evolve into pneumonia and/or sinus infections. This invasive disease is caused by germs entering the body and infecting areas of the body in which bacteria don’t normally grow. If the disease becomes very severe, hospitalization is necessary in order to treat the virus and prevent sudden death. Due to the extremity of pneumococcal disease, it’s vital that one understands the formation of the disease, how it gets transmitted, and why it advances so rapidly.
Epidemiology of Pneumococcus
According to Elaine Tuomanen, of the Department of Infectious Diseases at St. Jude Children’s Hospital (Memphis, TN), pneumococcus originates from the “classic Gram-positive extracellular pathogen”. Generally, pneumococcal disease spreads from person to person through droplets, aerosols, and nasopharyngeal colonization (a pneumococcus prerequisite). Primarily, the bacteria enter the nasal cavity and attach itself to nasopharyngeal epithelial cells. Then, the bacteria may colonize or progress further to harm other organs in the body. Some of the most dangerous places for the bacteria to travel are the ears, lungs, and mucosal barrier. Tuomanen explains that these organs are the most sensitive to pneumococcus because the bacteria can most easily enter the bloodstream from these locations- developing into meningitis and septicemia.
Risk Factors
Even though anyone can contract the pneumococcal disease, infants and the elderly are typically the most at-risk groups. Researchers at the CDC (Center for Disease Control and Prevention) have found that being a certain age and attaining chronic medical conditions can make one more, or less, susceptible to getting pneumococcus bacteria.
Children are commonly more at risk to contract the pneumococcal disease due to their lack of vaccination, caused by early age. Specifically, these three contributors can increase the likeliness of pneumococcus bacteria in adolescents:
Being younger than 2 years old
Having certain acute illnesses (i.e: sickle cell disease, HIV infection, diabetes, immunocompromising conditions, nephrotic syndrome, or chronic heart, lung, kidney, or liver disease)
Leaking caused by the use of a cochlear implant (cerebrospinal fluid leaking and surrounding the brain)
Likewise, adults at the age of 65 and older are also more at risk for the contraction of pneumococcal disease. Although most adults get the pneumococcal vaccine, the disease can still be spread by respiratory secretions; saliva (kissing), and mucus (sneezing, coughing). More specific contributors to pneumococcal disease in the elderly are:
Having a chronic illness (liver, kidney, or lung [including chronic obstructive lung disease, emphysema, and asthma] disease; diabetes; or alcoholism)
Living with weak immune systems caused by chronic diseases (HIV/AIDS, cancer, damaged spleen)
Leaking caused by the use of a cochlear implant (cerebrospinal fluid leaking and surrounding the brain)
Excessive smoking of cigarettes
Prevention and Treatment for Pneumococcal Disease
Epidemiologists suggest that the best way to keep up with the evolution of the pneumococcal disease is to keep track of updated vaccines. Obviously, receiving the vaccine doesn’t completely eliminate the chances of contracting pneumococcus bacteria but minimizes the chances of receiving it. Also, medical professionals often recommend getting the influenza vaccine annually to keep one’s immune system strong during colder months. As of now, the U.S. distributes two kinds of preventative pneumococcal vaccines:
Pneumococcal conjugate vaccine (PCV13 or Prevnar 13®)
Pneumococcal polysaccharide vaccine (PPSV23 or Pneumovax 23®)
If someone were to contract the pneumococcal disease, treatment plans would be based on how invasive the disease seems to be. For example, if doctors are suspicious of invasive pneumococcal disease (demonstrated by bloodstream infections or meningitis), they’ll most likely collect samples of cerebrospinal fluid and blood to send to a laboratory. On the other hand, if patients experience lighter symptoms like sinus infections, doctors will most likely diagnose the patient based on their previous medical history.
No matter what spectrum of pneumococcal disease that a patient might have, broad-spectrum antibiotics are highly probable to be prescribed. Medical professionals like to rely on broad-spectrum antibiotics because it can treat a wide range of bacteria. In most cases, doctors will put an infected patient on a broad-spectrum antibiotic and transfer them to a more fixated medication (narrow-antibiotic) once the sensitivity of the bacteria is more commonly understood.
Conclusion
Along with the evolution of diseases, the evolution of medicine is also occurring. Thankfully, more advanced research and medicinal work make it easier to treat pneumococcal disease and decrease its mortality rate. Birgitta Henriques-Normark, of the Department of Microbiology, Tumor and Cell Biology at the Karolinska Institute (Stockholm, Sweden), reported that 5% of deaths in the U.S. can be attributed to the contraction of pneumococcal disease. Hopefully, as we scientists further familiarize themselves with pneumococcus, society can squash that 5% and ensure well-being for all.
References:
Henriques-Normark, Birgitta, and Elaine I Tuomanen. "The pneumococcus: epidemiology, microbiology, and pathogenesis." Cold Spring Harbor perspectives in medicine vol. 3,7 a010215. 1 Jul. 2013, doi:10.1101/cshperspect.a010215
"Pneumococcal Disease: Prevention." Center for Disease Control and Prevention (CDC), U.S. Department of Health and Human Services, 21 Nov. 2019, www.cdc.gov/pneumococcal/about/prevention.html. Accessed 15 Nov. 2020.
Tuomanen, Elaine I. Pneumococcal Transformation and Virulence. Memphis, TN, St. Jude Children's Research Hospital. Grantome, grantome.com/grant/NIH/R01-AI036445-05. Accessed 15 Nov. 2020.
Weiser, Jeffrey N et al. "Streptococcus pneumoniae: transmission, colonization and invasion." Nature reviews. Microbiology vol. 16,6 (2018): 355-367. doi:10.1038/s41579-018-0001-8
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