Pneumococcal Infection

Pneumococcal infection is a serious bacterial disease caused by Streptococcus pneumoniae that can affect people of all ages, causing illnesses ranging from ear infections to life-threatening pneumonia and meningitis.

Table of contents

• What is pneumococcal infection
• Types of infections caused by pneumococcus
• Who is at increased risk
• How the infection spreads
• Symptoms and complications
• Testing and diagnosis
• Treatment
• Prevention through vaccination

What is pneumococcal infection

Pneumococcal infection is any illness caused by bacteria called Streptococcus pneumoniae, also known as pneumococcus. These bacteria are a type of germ that can infect different parts of the body^[1]. The bacteria are shaped like spheres and commonly live in the upper airways of healthy people, particularly during winter and early spring^[5].

Scientists have identified about 100 different types of pneumococcus bacteria. However, most serious infections are caused by only a few of these types^[2][5]. Pneumococcal disease is a leading cause of serious illness and death worldwide, with an estimated one million deaths each year^[4].

Types of infections caused by pneumococcus

Pneumococcal bacteria can cause two main categories of disease. The first type is called noninvasive disease, which is more common and less serious. These infections do not spread to major organs or the blood. The second type is invasive disease, which is more severe and occurs when bacteria invade the blood, major organs like the lungs, or areas of the body that normally have no bacteria, such as the brain or bones^[2].

The bacteria can cause many different illnesses depending on which part of the body becomes infected^[1]:

• Pneumonia is an infection of the lungs. This is the most common serious form of pneumococcal disease^[6]
• Meningitis is an infection of the membranes that surround the brain and spinal cord. This is an extremely serious condition with a high death rate^[4]
• Bacteremia is an infection where bacteria invade the bloodstream. This can lead to sepsis, which is a widespread dangerous reaction throughout the body^[1]
• Otitis media is a middle ear infection, which is very common in children^[1]
• Sinusitis is an infection of the air-filled spaces in the face^[1]

Less commonly, pneumococcal bacteria can also infect joints (causing septic arthritis), bones (causing osteomyelitis), heart valves, or the abdominal cavity^[2][4].

Pneumococcal meningitis and bloodstream infections can result in severe disabilities including brain damage, hearing loss, or even surgical removal of limbs. These conditions can be fatal if left untreated^[2]. Studies show that pneumococcal meningitis kills about 1 in 6 older patients, while bloodstream infection kills about 1 in 8 adults^[3].

Who is at increased risk

Anyone can develop pneumococcal infection, but certain groups of people face higher risks^[1]. Young children, especially those under 2 years of age, and older adults over 65 years are at the highest risk of getting pneumococcal disease and having serious complications from it^[3][4].

People with certain health conditions also have increased risk^[2][3]:

• Chronic heart, lung, liver, or kidney disease
• Diabetes
• Sickle cell disease or a damaged or removed spleen
• Conditions that weaken the immune system, such as HIV infection or certain cancers
• Solid organ transplants
• Cochlear implants (a device placed in the ear to help with hearing)
• Leaks of cerebrospinal fluid (the fluid that surrounds the brain and spinal cord)

Other factors that increase risk include smoking cigarettes, alcohol use disorder, residence in long-term care facilities, and being descended from certain Aboriginal, Alaskan Native, or American Indian groups^[2][5].

Having influenza (flu) or chronic bronchitis can damage the lining of the airways and make it easier for pneumococcal bacteria to cause infection^[5]. Even healthy older adults tend to have more severe symptoms and complications when they get a pneumococcal infection^[5].

How the infection spreads

Pneumococcal bacteria spread from person to person through direct contact with respiratory secretions like saliva or mucus^[1]. This happens when an infected person coughs or sneezes, releasing tiny droplets into the air that contain the bacteria^[3][5].

People can also get infected through close contact with someone who has the bacteria. The bacteria can spread when infected droplets settle on surfaces and then reach the mouth, nose, or eyes through contact, such as a handshake^[7].

Some people, especially children, can carry pneumococcal bacteria in their nose and throat without being sick themselves. These people can still spread the bacteria to others^[3]. Spread is more likely to happen among people in crowded settings such as nursing homes, hospitals, prisons, schools, day care centers, or shelters^[5].

While pneumococcal infections seem to be more common during winter and spring, they can occur at any time of year^[2][4].

Symptoms and complications

The symptoms of pneumococcal infection depend on which part of the body is infected^[1]. Most pneumococcal infections cause fever and a general feeling of illness, along with other symptoms specific to the infected area^[5].

For pneumococcal pneumonia, symptoms often begin suddenly and include fever, chills, feeling generally unwell, shortness of breath, and cough. The cough may bring up sputum (mucus) that is rust-colored. People commonly experience sharp, stabbing chest pains on one side that get worse with deep breathing or coughing^[5]. In about half of people with pneumococcal pneumonia, fluid builds up between the layers of tissue covering the lungs, which can make breathing more difficult^[5].

For pneumococcal meningitis, symptoms include fever, severe headache, and a general feeling of illness. People develop a stiff neck that makes it painful and difficult to lower the chin to the chest, though this may not be obvious early in the disease^[5]. Other symptoms may include confusion, sensitivity to light, nausea, and vomiting^[3]. Infants with meningitis may not show a stiff neck but may simply refuse to eat and appear irritable or sluggish^[5].

For other types of pneumococcal infections, symptoms include^[4]:

• Sinusitis: aching face, blocked nose, yellow-green mucus from the nose, and headache
• Ear infection: painful ear, hearing loss, high temperature, nausea, and vomiting
• Bloodstream infection: fever, headache, and muscle aches and pains
• Joint infection: joint pain, swelling, and reduced ability to move the joint
• Bone infection: bone pain, reduced mobility of the affected part, and fever

People with serious pneumococcal infections may experience a combination of high fever, chills, cough, shortness of breath, chest pain, stiff neck, confusion, and sensitivity to light^[3]. Early diagnosis and treatment are very important for serious pneumococcal infections^[3].

Testing and diagnosis

For serious infections like meningitis or bloodstream infection, healthcare providers will collect samples of cerebrospinal fluid or blood. Cerebrospinal fluid is the fluid that surrounds the brain and spinal cord^[1]. These samples are sent to a laboratory where technicians try to grow the bacteria. Growing the bacteria helps identify the specific type causing the infection^[1].

Laboratories may also use molecular detection methods, which are tests that look for specific genetic material from the bacteria in the samples^[1]. For pneumococcal pneumonia in adults, healthcare providers can use a urine test to help make a diagnosis^[1].

Knowing the cause of the infection helps healthcare providers choose the right treatment, including which antibiotic will work best. The bacteria are tested to see which antibiotics are effective, a process called susceptibility testing^[1][5].

For milder infections like ear and sinus infections, healthcare providers usually make a diagnosis based on the person’s medical history and physical examination findings^[1].

When pneumonia is suspected, chest x-rays are taken to look for signs of lung infection. Doctors may take a sample of sputum (mucus coughed up from the lungs) and examine it under a microscope^[5].

Treatment

Healthcare providers use antibiotics to treat pneumococcal infections^[1]. Treatment typically involves antibiotics, and it’s important to begin treatment as soon as the diagnosis is made^[2].

For infections that do not require hospitalization, doctors typically prescribe a single antibiotic or a combination of two different oral antibiotics. The specific antibiotics used may include macrolides, beta-lactams (such as penicillin or amoxicillin), or quinolones^[11][12].

It is very important to take all the medicine exactly as prescribed, even if you start feeling better before finishing it. If you stop taking the antibiotic too soon, the bacterial infection and pneumonia may come back. The infection may also become resistant to the antibiotic, making treatment more difficult in the future^[1].

However, some pneumococcal bacteria have become resistant to certain antibiotics that were once used to treat these infections. This means the antibiotics no longer work as well against the bacteria^[1]. Since the 1990s, many pneumococcal bacteria in the United States have shown decreased susceptibility to penicillin and other commonly used antibiotics^[10]. Antibiotic testing shows which antibiotics will be most successful at treating the specific infection^[1].

At the beginning of treatment for serious pneumococcal infections, healthcare providers typically include broad-spectrum antibiotics, which work against many types of bacteria. Once testing results come back, they may switch to a more targeted antibiotic^[11].

Patients with serious infections will require hospitalization. For very severe infections, appropriate source control measures may be needed, such as draining any abscesses (collections of pus)^[7].

Prevention through vaccination

Vaccination is the best way to prevent pneumococcal disease^[1][3]. People can get pneumococcal disease more than once, so vaccination is important even for those who have had the infection before^[1].

In the United States, there are two types of pneumococcal vaccines available: pneumococcal conjugate vaccines and pneumococcal polysaccharide vaccines^[3]. Several pneumococcal conjugate vaccines are available, including PCV13, PCV15, PCV20, and PCV21. There is one pneumococcal polysaccharide vaccine called PPSV23^[3].

The Centers for Disease Control and Prevention (CDC) recommends pneumococcal vaccination for^[1][3]:

• All children younger than 5 years old
• People aged 5 through 49 years old with certain risk conditions
• All adults 50 years or older

For young children, the pneumococcal conjugate vaccine helps protect against 13 types of pneumococcal bacteria. It is given as part of routine childhood immunizations. In babies, it’s given as a three- or four-dose series beginning at 2 months of age, with the final dose given by 15 months^[22].

Vaccine recommendations vary by age and risk group. Many at-risk adults have not been vaccinated against pneumococcal disease, so it’s important to talk with a healthcare professional about whether pneumococcal vaccination is right for you^[3].

Having influenza (flu) increases the risk of getting pneumococcal disease, so protection against pneumococcal disease is especially important during flu season. If both flu and pneumococcal vaccines are due, they can be given during the same visit, but they should be given in different injection sites^[3].

In addition to vaccination, other steps can help protect against pneumococcal infection. Washing hands often helps prevent spreading viruses and bacteria that may cause pneumonia. Taking care of teeth and gums may help prevent some types of pneumonia. Not smoking and avoiding secondhand smoke are also important, as smoke can damage the airways and make infection easier^[22].