Final answer:
A brain abscess is commonly caused by infections spreading from other body parts. The primary pathogens involved in such serious infections, potentially leading to brain abscesses, are Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae, all of which can breach mucous membranes, enter the bloodstream, and result in meningitis.
Step-by-step explanation:
The most common cause of a brain abscess is often secondary to infections from elsewhere in the body, such as the sinuses, ears, teeth, or lungs. When looking at the specific pathogens, the most common causes of bacterial meningitis, which is a serious infection of the membranes covering the brain and spinal cord and can lead to a brain abscess, are Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae. These bacteria are similar in that they all have the capacity to colonize and breach the mucous membranes of the oropharynx and nasopharynx, enter the bloodstream, spread throughout the body, and potentially establish an infection that can result in meningitis or a brain abscess. They can be particularly dangerous and can lead to severe complications such as brain damage and even death if not treated promptly with appropriate antibacterial therapy.