Bacterial Meningitis: Types, Symptoms, Causes, and Treatment

Bacterial meningitis, a form of meningitis that stems from a bacterial infection, is more severe than viral meningitis — but it’s also rarer.

More than 1.2 million cases of bacterial meningitis are estimated to occur worldwide each year. (1)

It’s hard to get precise numbers for the rate of incidence, but according to a 2011 study, there were approximately 3,200 cases of bacterial meningitis and 500 deaths from the disease in the United States between 2003 and 2007. (2)

The disease has three main symptoms:

• Stiff neck
• Headache
• Fever

If your neck is so stiff that you can’t touch your chin to your chest, call a doctor immediately.

Other symptoms include:

• Sensitivity to light (photophobia)
• Confusion
• Seizures
• Coma

Bacterial meningitis can also cause the following complications:

• Brain damage
• Hearing loss
• Learning disabilities
• Death

Common types of bacterial meningitis are:

• Pneumococcal meningitis
• Meningococcal meningitis
• Listeria monocytogenes meningitis
• Neonatal meningitis
• Hemophilus (Hib) meningitis

Pneumococcal meningitis, caused by the bacteria Streptococcus pneumoniae, is the most common type of bacterial meningitis in adults in the United States. (3)

Meningococcal meningitis, caused by the bacteria Neisseria meningitidis, is the most common type of bacterial meningitis among teenagers and children under age 5. (1)

Meningococcal meningitis is meningitis due to the bacteria Neisseria meningitidis. In the United States, meningococcal disease is caused mainly by three strains of Neisseria meningitidis: B, C, and Y. (4)

According to the National Meningitis Association, the B strain accounts for one-third of meningococcal disease in the United States and is the most common cause of bacterial meningitis in teenagers. (5)

Newborns are most likely to develop meningitis from the following bacteria (6):

• Group B streptococcus ( GBS )
• E. coli

Group B strep infection is the main cause of neonatal meningitis; infants contract it from their mothers during birth.

Because of this, the CDC recommends that if you are pregnant, you should talk with your care team about getting a GBS test when you are 35 to 37 weeks pregnant. (7)

Doctors will administer antibiotics during labor to women who test positive in order to prevent infection in newborns.

Premature infants are at particular risk for bacterial meningitis caused by E. coli. (8) This bacteria, which is becoming resistant to antibiotics, is hard to assess and hard to treat.

Listeria monocytogenes is a bacteria that resides in food, including in processed meats, like deli meats and hot dogs, and in unpasteurized milks and cheeses.

Pregnant women, infants, and people with weak immune systems, such as the elderly, are also at higher risk of developing meningitis from Listeria monocytogenes. Pregnant women can pass the bacteria to their newborns, potentially resulting in neonatal meningitis.

There are a number of ways for pregnant women to reduce their risk of getting a listeria infection and passing it on to their newborns, including by:

• Fully cooking meat and poultry
• Eliminating certain foods from the diet while pregnant, including unpasteurized (raw) milk and soft cheeses, such as Brie, Camembert, queso fresco, and feta
• Either avoiding lunch meats and hot dogs while pregnant or heating them to at least 165 degrees F (74 degrees C) before eating
• Keeping the kitchen environment clean before, during, and after cooking
• Thoroughly rinsing raw produce
• Scrubbing firm produce

Haemophilus influenzae type b (also called Hib) was once a common cause of meningitis in the United States, particularly among infants and children.

This agent used to be responsible for up to 48 percent of all bacterial meningitis cases, according to a 2010 review. (9)

The Hib vaccine has virtually eliminated Hib meningitis in infants and children in the United States, though Hib is still a major cause of pediatric meningitis around the world.

Other bacteria can also cause meningitis, particularly in people with weakened immune systems or those who’ve had head trauma or brain surgery. Among these bacteria are:

• Salmonella
• Staphylococcus aureus
• Pseudomonas aeruginosa 

Bacterial meningitis is passed to other people through the exchange of saliva or mucus, such as through kissing, coughing, or sneezing.

About 1 in 10 people carry meningococcal bacteria in their nose or throat but don’t get sick from it; these carriers can still transmit the bacteria without knowing it. (10)

Risk factors for bacterial meningitis include:

• Age — infants, teens, and young adults are at particular risk
• Spending time in crowded quarters, such as in college or boarding school dormitories, military barracks, or daycare settings
• Diseases, medication, or surgical procedures that weaken the immune system
• Working with meningitis-causing bacteria
• Traveling to the so-called “meningitis belt” in sub-Saharan Africa during the dry season, which is December through June (11,12)

Bacterial meningitis is treated with:

• Antibiotics
• Dexamethasone
• Fluid replacement

Antibiotics can reduce the risk of death to below 15 percent. (13)

Preventive antibiotics can also help protect you from becoming infected with N. meningitidis or Hib if you have close contact with someone with those forms of meningitis.

Dexamethasone is a steroid that helps control swelling and pressure in the skull.

There are vaccines for three kinds of bacterial meningitis:

• Pneumococcal
• Meningococcal
• Hib

There are two types of pneumococcal meningitis vaccines available in the United States. They are: (14)

• Prevnar 13
• Pneumovax 23 

There are four types of meningococcal vaccines available. Two protect against the B strain of meningococcus, which is most likely to cause an outbreak. They are:

• Trumenba
• Bexsero

Two vaccines protect against the A, C, W-135, and Y strains. They are:

• Menactra
• Menveo

The CDC recommends that people traveling to or residing in the meningitis belt in sub-Saharan Africa receive a meningococcal meningitis vaccine that protects against those four strains. (14) This map from the CDC denotes the countries that are at high risk.

There are several types of vaccines for Hib as well; they are recommended for children under age 5. (15) They include:

• ActHIB
• Hiberix
• PedvaxHIB
• Pentacel (this also prevents tetanus, diphtheria, whooping cough, and polio)

Additional reporting by Carlene Bauer.