Meningitis is an infection of the spinal fluid and the meninges, which are three layers of protective tissue that surround the brain and spinal cord. Meningitis that occurs during the first three months of life is termed neonatal meningitis. When the infection presents during the first week of life, it is early-onset disease. Meningitis that presents between the second week of life through 3 months of age is late-onset disease. While many types of bacteria can potentially cause neonatal meningitis, most cases are due to infections with group B strep, E. coli or Listeria monocytogenes.
Group B Strep
The U.S. Centers for Disease Control and Prevention, or CDC, reports that group B streptococcus is the most common cause of neonatal meningitis in the United States. Approximately 10 to 30 percent of pregnant women carry group B streptococcus, also known as group B strep, in the rectum or lower genital tract. The bacteria may infect the baby at or near the time of birth, potentially leading to meningitis. In a 2008 article published by "The Journal of the American Medical Association," Dr. C. Phares and colleagues reported that approximately 7 percent of newborns with early-onset group B strep infection and 27 percent with late-onset disease present with meningitis.
Escherichia Coli
"The Merck Manual for Healthcare Professionals" reports that Escherichia coli, or E. coli, is a leading cause of neonatal meningitis. Dr. Kenneth Todar explains in his electronic reference book, "Todar's Online Textbook of Bacteriology," that there are more than 700 known types of E. coli. The types most often associated with neonatal meningitis are those in the K-1 grouping. K-1 E. coli strains have features that provide resistance to destruction by the immune system. The ability to resist the immune system contributes to the capacity of these bacteria to invade the bloodstream and central nervous system.
Listeria Monocytogenes
Listeriosis is a food-borne illness caused by the bacterium Listeria monocytogenes. The CDC reports that listeriosis most commonly affects people with a weakened system, the elderly, and pregnant women and newborns. Pregnant women have approximately a 20-fold greater risk of listeriosis compared to healthy, non-pregnant adults. When a pregnant woman contracts Listeria monocytogenes, the bacteria can cross the placenta and infect her baby. The infection may cause stillbirth or the baby may be born with listeriosis, which can present as meningitis. During the first three months of life, newborns remain at high risk for meningitis due to Listeria monocytogenes. To avoid contracting listeriosis, CDC recommends pregnant women should avoid unpasteurized milk and dairy products, raw or undercooked meat products including hot dogs and luncheon meats, refrigerated smoked seafood, and refrigerated meat spreads or pâtés.
References
- Merck Manual for Healthcare Professionals: Neonatal Bacterial Meningitis
- Journal of the American Medical Association: Epidemiology of Invasive Group B Streptococcal Disease in the United States, 1999-2005
- U.S. Centers for Disease Control and Prevention, MMWR: Prevention of Perinatal Group B Streptococcal Disease
- Todar's Online Textbook of Bacteriology: Pathogenic E. coli, Neonatal Meningitis
- U.S. Centers for Disease Control and Prevention: Listeriosis
