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Pneumococcal Infections


Larry M. Bush

, MD, FACP, Charles E. Schmidt College of Medicine, Florida Atlantic University

Reviewed/Revised Mar 2023
Topic Resources

Pneumococcal infections are caused by the gram-positive Overview of Gram-Positive Bacteria Gram-positive bacteria are classified by the color they turn after a chemical called Gram stain is applied to them. Gram-positive bacteria stain blue when this stain is applied to them. (Other... read more , sphere-shaped (coccal) bacteria (see figure How Bacteria Shape Up How Bacteria Shape Up How Bacteria Shape Up ) Streptococcus pneumoniae (pneumococci). These bacteria commonly cause pneumonia, meningitis, sinusitis, and middle ear infection.

  • Pneumococcal bacteria are dispersed in the air when infected people cough or sneeze.

  • Pneumococcal infections usually cause fever and a general feeling of illness, with other symptoms depending on which part of the body is infected.

  • Diagnosis may be based on symptoms or identification of the bacteria in samples of infected material.

  • Penicillin or another antibiotic is usually effective treatment.

  • Young children are routinely vaccinated against these infections, and vaccination is also recommended for all people 65 years of age and older and all people at high risk.

There are more than 90 types of pneumococci. However, most serious infections are caused by only a few types.

Pneumococci commonly reside in the upper respiratory tract of healthy people, their natural host, particularly during the winter and early spring. The bacteria spread to other people when they do the following:

  • Inhale infected droplets dispersed by sneezing or coughing

  • Come in close contact with an infected person

Spread is more likely among people in crowded settings, such as people who live, stay, or work in nursing homes or long-term care facilities, hospital wards, prisons, military bases, universities or schools, shelters for the homeless, or day care centers.

Risk factors

Certain conditions increase the risk of developing and the severity of pneumococcal infections:

Also, older people, even if healthy, tend to have more severe symptoms and complications when they get a pneumococcal infection.

Symptoms and Diagnosis of Pneumococcal Infections

Symptoms of pneumococcal infections vary depending on the site of the infection.

Most pneumococcal infections occur in the

Pneumococcal pneumonia

Often, symptoms of pneumococcal pneumonia Overview of Pneumonia Pneumonia is an infection of the small air sacs of the lungs (alveoli) and the tissues around them. Pneumonia is one of the most common causes of death worldwide. Often, pneumonia is the final... read more Overview of Pneumonia begin suddenly. People have fever, chills, a general feeling of illness (malaise), shortness of breath, and a cough. The cough brings up sputum that is rust-colored.

Commonly, sharp, stabbing chest pains occur on one side. Deep breathing and coughing make the pains worse. In about 40% of people, fluid accumulates between the layers of tissue that cover the lungs (called pleural effusion Pleural Effusion Pleural effusion is the abnormal accumulation of fluid in the pleural space (the area between the two layers of the thin membrane that covers the lungs). Fluid can accumulate in the pleural... read more Pleural Effusion ). Pleural effusion may contribute to chest pain and make breathing difficult.

Chest x-rays are taken to look for signs of pneumonia. Doctors take a sample of sputum and examine it under a microscope. A sample of sputum, pus, or blood may be sent to a laboratory to grow (culture) bacteria. Pneumococcal bacteria are easily identified. They are also tested to see which antibiotics are effective (a process called susceptibility testing Testing a Microorganism's Susceptibility and Sensitivity to Antimicrobial Drugs Infectious diseases are caused by microorganisms, such as bacteria, viruses, fungi, and parasites. Doctors suspect an infection based on the person's symptoms, physical examination results,... read more ).

Pneumococcal meningitis

People with pneumococcal meningitis Acute Bacterial Meningitis Acute bacterial meningitis is rapidly developing inflammation of the layers of tissue that cover the brain and spinal cord (meninges) and of the fluid-filled space between the meninges (subarachnoid... read more have fever, headache, and a general feeling of illness (malaise). They have a stiff neck that makes lowering the chin to the chest painful and difficult, but this problem is not always obvious early in the disease.

Pneumococcal meningitis may lead to complications, such as

  • Hearing loss (in up to 50% of people)

  • Seizures

  • Learning disabilities

  • Mental dysfunction

The diagnosis of pneumococcal meningitis requires a spinal tap Spinal Tap Diagnostic procedures may be needed to confirm a diagnosis suggested by the medical history and neurologic examination. Imaging tests commonly used to diagnose nervous system (neurologic) disorders... read more Spinal Tap (lumbar puncture) to obtain a sample of the fluid that surrounds the brain and spinal cord (cerebrospinal fluid). The sample is checked for signs of infection, such as white blood cells and bacteria.

Pneumococcal otitis media

Pneumococcal bacteria causes about 30 to 40% of all cases of otitis media in children. Pneumococcal otitis media commonly recurs.

The diagnosis of pneumococcal otitis media is usually based on symptoms and results of a physical examination. Cultures and other diagnostic tests are usually not done.

Pneumococcal sinusitis

Pneumococcal sinusitis Sinusitis Sinusitis is inflammation of the sinuses, most commonly caused by a viral or bacterial infection or by an allergy. Some of the most common symptoms of sinusitis are pain, tenderness, nasal congestion... read more most commonly affects the sinuses located in the cheekbones (the maxillary sinuses) and the sinuses located on either side of the nasal cavity (the ethmoid sinuses). The infection causes sinus pain and pus discharged from the nose. The infection may become chronic. The infection may extend into the skull and cause complications such as the following:

A doctor bases the diagnosis of sinusitis on the typical symptoms. A computed tomography (CT) scan is done when people have symptoms of complications or when people have chronic sinusitis.

Pneumococcal bacteremia

If bacteremia is suspected, doctors usually take a sample of blood so they can try to grow (culture) the bacteria in the laboratory and identify it.

Despite antibiotic treatment, pneumococcal bacteremia often causes death, especially in older people, people who have disorders that weaken their immune system, or people who have no spleen.

Treatment of Pneumococcal Infections

  • Antibiotics

Penicillin (or the related antibiotics, ampicillin and amoxicillin) is used for most pneumococcal infections. It is usually taken by mouth but, if the infection is severe, may be given intravenously.

Pneumococci that are resistant to penicillin are becoming more common. Thus, other antibiotics, such as ceftriaxone, cefotaxime, fluoroquinolones (such as levofloxacin), vancomycin, lefamulin, or omadacycline, are often used.

Vancomycin is not always effective against meningitis caused by pneumococci. Thus, people with meningitis are usually given ceftriaxone or cefotaxime, rifampin, or both, as well as vancomycin.

Prevention of Pneumococcal Infections

Pneumococcal infections can be prevented with vaccines and, for certain people, antibiotics.


Two types of pneumococcal vaccines are available: conjugate and polysaccharide.

  • The conjugate vaccine PCV13 protects against 13 types of pneumococcal bacteria (pneumococci).

  • The conjugate vaccine PCV15 protects against 15 types of pneumococci.

  • The conjugate vaccine PCV20 protects against 20 types of pneumococci.

  • The polysaccharide vaccine PPSV23 protects against 23 types of pneumococci.


If children under 5 years old do not have a spleen or if their spleen is not functioning, they may be given antibiotics (such as penicillin) in addition to the vaccine. In such cases, antibiotics may be continued throughout childhood and into adulthood.

More Information

The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Amoxil, Dispermox, Moxatag, Moxilin , Sumox, Trimox
Ceftrisol Plus, Rocephin
Iquix, Levaquin, Levaquin Leva-Pak, Quixin
FIRVANQ, Vancocin, Vancocin Powder, VANCOSOL
Xenleta, Xenleta Solution
Rifadin, Rifadin IV, Rimactane
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