Bacterial Meningitis

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• Causes
• Risk Factors
• How It Spreads
• Signs & Symptoms
• Diagnosis
• Treatment
• Prevention

Bacterial meningitis is very serious and can be deadly. Death can occur in as little as a few hours. Most people recover from meningitis. However, permanent disabilities (such as brain damage, hearing loss, and learning disabilities) can result from the infection.
Several types of bacteria can cause meningitis. Leading causes in the United States include

• Streptococcus pneumoniae
• Group B Streptococcus
• Neisseria meningitidis
• Haemophilus influenzae
• Listeria monocytogenes

These bacteria can also be associated with another serious illness, sepsis. Sepsis is the body’s extreme response to infection. Without timely treatment, sepsis can quickly lead to tissue damage, organ failure, and death.

Causes

Common causes of bacterial meningitis vary by age group:

• Newborns: Group B Streptococcus, S. pneumoniae, L. monocytogenes, E. coli
• Babies and children: S. pneumoniae, N. meningitidis, H. influenzae type b (Hib), group B Streptococcus
• Teens and young adults: N. meningitidis, S. pneumoniae
• Older adults: S. pneumoniae, N. meningitidis, Hib, group B Streptococcus, L. monocytogenes

Risk Factors

Certain people are at increased risk for bacterial meningitis. Some risk factors include:

• Age: Babies are at increased risk for bacterial meningitis compared to people in other age groups. However, people of any age can develop bacterial meningitis. See section above for which bacteria more commonly affect which age groups.
• Group setting: Infectious diseases tend to spread where large groups of people gather. College campuses have reported outbreaks of meningococcal disease, caused by N. meningitidis.
• Certain medical conditions: There are certain medical conditions, medications, and surgical procedures that put people at increased risk for meningitis.
• Working with meningitis-causing pathogens: Microbiologists routinely exposed to meningitis-causing bacteria are at increased risk for meningitis.
• Travel: Travelers may be at increased risk for meningococcal disease, caused by N. meningitidis, if they travel to certain places, such as:
  • The meningitis belt in sub-Saharan Africa, particularly during the dry season
  • Mecca during the annual Hajj and Umrah pilgrimage

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How It Spreads

Generally, the germs that cause bacterial meningitis spread from one person to another. Certain germs, such as L. monocytogenes, can spread through food.
How people spread the germs often depends on the type of bacteria. It is also important to know that people can have these bacteria in or on their bodies without being sick. These people are “carriers.” Most carriers never become sick, but can still spread the bacteria to others.
Here are some of the most common examples of how people spread each type of bacteria to each other:

• Group B Streptococcus and E. coli: Mothers can pass these bacteria to their babies during birth.
• Hib and S. pneumoniae: People spread these bacteria by coughing or sneezing while in close contact with others, who breathe in the bacteria.
• N. meningitidis: People spread these bacteria by sharing respiratory or throat secretions (saliva or spit). This typically occurs during close (coughing or kissing) or lengthy (living together) contact.
• E. coli: People can get these bacteria by eating food prepared by people who did not wash their hands well after using the toilet.

People usually get sick from E. coli and L. monocytogenes by eating contaminated food.

Signs and Symptoms

Pregnancy

Pregnant women are at increased risk of developing listeriosis, an infection caused by the bacteria L. monocytogenes. Listeriosis is typically a mild illness for pregnant women, but it causes severe disease in the fetus or newborn baby. Pregnant women can reduce the risk of meningitis caused by L. monocytogenes by avoiding certain foods and safely preparing others.
Pregnant women can pass group B Streptococcus (group B strep) to their baby during delivery. A newborn infected with group B strep can develop meningitis or other serious infections soon after birth. Talk with your doctor or midwife about getting a group B test when you are 36 through 37 weeks pregnant. Doctors give antibiotics (during labor) to women who test positive in order to prevent infection in newborns.

Meningitis symptoms include sudden onset of

• Fever
• Headache
• Stiff neck

There are often other symptoms, such as

• Nausea
• Vomiting
• Photophobia (eyes being more sensitive to light)
• Altered mental status (confusion)

Newborns and babies may not have or it may be difficult to notice the classic symptoms listed above. Instead, babies may

• Be slow or inactive
• Be irritable
• Vomit
• Feed poorly

In young babies, doctors may also look for a bulging fontanelle (soft spot on infant’s head) or abnormal reflexes. If you think your baby or child has any of these symptoms, call the doctor right away.
Symptoms of bacterial meningitis can appear quickly or over several days. Typically they develop within 3 to 7 days after exposure.
Later symptoms of bacterial meningitis can be very serious (e.g., seizures, coma). For this reason, anyone who thinks they may have meningitis should see a doctor as soon as possible.

Diagnosis

If a doctor suspects meningitis, they will collect samples of blood or cerebrospinal fluid (fluid near the spinal cord). A laboratory will test the samples to see what is causing the infection. It is important to know the specific cause of meningitis so the doctors know how to treat it.

Treatment

Doctors treat bacterial meningitis with a number of antibiotics. It is important to start treatment as soon as possible.

Prevention

Vaccines are the most effective way to protect against certain types of bacterial meningitis. There are vaccines for 3 types of bacteria that can cause meningitis:

• Meningococcal vaccines help protect against N. meningitidis
• Pneumococcal vaccines help protect against S. pneumoniae
• Hib vaccines help protect against Hib

Make sure you and your child are vaccinated on schedule.
Like with any vaccine, the vaccines that protect against these bacteria are not 100% effective. The vaccines also do not protect against all the types (strains) of each bacteria. For these reasons, there is still a chance vaccinated people can develop bacterial meningitis.
Pregnant women should talk to their doctor or midwife about getting tested for group B Streptococcus. Women receive the test when they are 36 through 37 weeks pregnant. Doctors give antibiotics (during labor) to women who test positive in order to prevent passing group B strep to their newborns.
Pregnant women can also reduce their risk of meningitis caused by L. monocytogenes. Women should avoid certain foods during pregnancy and safely prepare others.
If someone has bacterial meningitis, a doctor may recommend antibiotics to help prevent other people from getting sick. Doctors call this prophylaxis. CDC recommends prophylaxis for:

• Close contacts of someone with meningitis caused by N. meningitidis
• Family members, especially if they are at increased risk, of someone with a serious Hib infection

Doctors or local health departments recommend who should get prophylaxis.
You can also help protect yourself and others from bacterial meningitis by maintaining healthy habits:

• Don’t smoke and avoid cigarette smoke
• Get plenty of rest
• Avoid close contact with people who are sick

This is especially important for people at increased risk for disease, including:

• Young babies
• Older adults
• People with weak immune systems
• People without a spleen or a spleen that doesn’t work the way it should

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Related Pages

• Preventing Infections in Pregnancy
• Meningococcal Disease
• Meningococcal Vaccine
• Pneumococcal Disease
• Pneumococcal Vaccine
• Haemophilus influenzae Disease, including Hib
• Hib Vaccine
• Group B Strep
• Listeriosis