People may contract bacterial meningitis if they come in contact with infected saliva, mucus or stool, as WebMD advises. These bacteria may also enter the body through ear and sinus infections, notes Mayo Clinic. The consumption of listeria-contaminated food may also cause meningitis.
Acute bacterial meningitis may result when specific bacteria enter the bloodstream and invade tissue surrounding the brain or spinal cord, causing inflammation, states WebMD. Certain strains of bacteria cause acute meningitis. These include Streptococcus pneumoniae or pneumococcus, which is the most common; Neisseria meningitidis or meningococcus; Haemophilus influenzae or haemophilus; and Listeria monocytogenes. Vaccines are available to reduce the incidents of acute bacterial meningitis from meningococcus and haemophilus.