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Learning objectives

  • Identify the most common bacteria that can cause infections of the nervous system
  • Compare the major characteristics of specific bacterial diseases affecting the nervous system

Bacterial infections that affect the nervous system are serious and can be life-threatening. Fortunately, there are only a few bacterial species commonly associated with neurological infections.

Bacterial meningitis

Bacterial meningitis is one of the most serious forms of meningitis. Bacteria that cause meningitis often gain access to the CNS through the bloodstream after trauma or as a result of the action of bacterial toxins. Bacteria may also spread from structures in the upper respiratory tract, such as the oropharynx, nasopharynx, sinuses, and middle ear. Patients with head wounds or cochlear implants (an electronic device placed in the inner ear) are also at risk for developing meningitis.

Many of the bacteria that can cause meningitis are commonly found in healthy people. The most common causes of non-neonatal bacterial meningitis are Neisseria meningitidis , Streptococcus pneumoniae , and Haemophilus influenzae . All three of these bacterial pathogens are spread from person to person by respiratory secretions. Each can colonize and cross through the mucous membranes of the oropharynx and nasopharynx, and enter the blood. Once in the blood, these pathogens can disseminate throughout the body and are capable of both establishing an infection and triggering inflammation in any body site, including the meninges ( [link] ). Without appropriate systemic antibacterial therapy, the case-fatality rate can be as high as 70%, and 20% of those survivors may be left with irreversible nerve damage or tissue destruction, resulting in hearing loss, neurologic disability, or loss of a limb. Mortality rates are much lower (as low as 15%) in populations where appropriate therapeutic drugs and preventive vaccines are available. Thigpen, Michael C., Cynthia G. Whitney, Nancy E. Messonnier, Elizabeth R. Zell, Ruth Lynfield, James L. Hadler, Lee H. Harrison et al., “Bacterial Meningitis in the United States, 1998–2007,” New England Journal of Medicine 364, no. 21 (2011): 2016-25.

a) Photo of brain. B) Photo of think layer on top of brain being pulled back by forceps.
(a) A normal human brain removed during an autopsy. (b) The brain of a patient who died from bacterial meningitis. Note the pus under the dura mater (being retracted by the forceps) and the red hemorrhagic foci on the meninges. (credit b: modification of work by the Centers for Disease Control and Prevention)

A variety of other bacteria, including Listeria monocytogenes and Escherichia coli , are also capable of causing meningitis. These bacteria cause infections of the arachnoid mater and CSF after spreading through the circulation in blood or by spreading from an infection of the sinuses or nasopharynx. Streptococcus agalactiae , commonly found in the microbiota of the vagina and gastrointestinal tract, can also cause bacterial meningitis in newborns after transmission from the mother either before or during birth.

The profound inflammation caused by these microbes can result in early symptoms that include severe headache, fever, confusion, nausea, vomiting, photophobia, and stiff neck. Systemic inflammatory responses associated with some types of bacterial meningitis can lead to hemorrhaging and purpuric lesions on skin, followed by even more severe conditions that include shock, convulsions, coma, and death—in some cases, in the span of just a few hours.

Questions & Answers

Types of micro organisms
Jennifer Reply
Who discovered plant and animal cell
Jennifer
Robert Hooke
Martha
Father of microbiology
Jennifer Reply
Antonie van Leeuwenhoek
Satarupa
Why are mitochondria and chloroplasts unable to multiply outside of a host cell?
Iqra Reply
iqra mitochondria arises from the division of existing mitochondria and they are fused together. they move around inside the cell with the interactions of the cytoskeleton that's why mitochondria unable to multiply outside the host cells chloroplasts has its own separate DNA from the plant cell.
Rana
short not on medical microbiology
Massah Reply
Hy
Iqra
hope you fine
Arif
love you
Arif
Assalamualaikum
Suhaib
arai yeh micro kai sth kis ko love hua
Umer
icrobiology is the scientific study of these microorganisms. Microorganisms are those organisms that are too small to see with the naked eye and include things like bacteria, fungi, and viruses
Suhaib
iqra iqbal
Arif
What is gram syaining?
Arif
to differentiate between gram positive and gram negative bacty
Umer
True
Arif
where you are from
Arif
i m frm sopore..kashmir
Umer
i m frm baramulla .. Kashmir
Umer
and u
Umer
umer
Arif
and i m from afghanistan lovely country
Arif
yes
Umer
thanks
Arif
medical microbiology means study of microorganisms which are beneficial or harmful for the body. mostly which are studied under microscope by structure and shape appearance. e.g bacteria, viruses, bacteriophage, fungus hyphae and some blood and other body fluids parasites e.g plasmodium etc.
Rana
arif bhai gram staining in which we are given different dyes to the bacterial cell wall and cytoplasm and nucleus.e.g giemsa stain
Rana
Gram staining uses crystal violet to stain cell walls iodine as a mordant and a fuchsin or safranin counterstain to mark all bacteria
Umer
Gram staining uses crystal violet to stain cell walls iodine as a mordant and a fuchsin or safranin counterstain to mark all bacteria
Umer
Gram staining uses crystal violet to stain cell walls iodine as a mordant and a fuchsin or safranin counterstain to mark all bacteria
Umer
Omar baba crystal violet iodine 70% alcohol fuchicine or safranine after every step washing must be done
Rana
hello
Cristy
*Fuchsin stain
Cristy
*Safranin
Cristy
thanks
Ganesh
difference between epidermophyton trichophyton and microsporum
Ankita Reply
plz answer the question
Iqra
epidermophyton type of fungi causes superficial and cutaneous mycoses trichophyton is also fungi type including parasitic varieties causes dermatophytosis microsporum is also type of fungi causes dermatophytosis.
Rana
ok
Iqra
Is this app perfect for preparation of exam?
Ankita
Ankita I totally disagree with your respected opinion. it's just minor helpful
Rana
disagree by me ?
Ankita
what is infectious
Fred Reply
Many poeple are die due to covid-19 virus
AMINU Reply
they become sick due to millions bacteria, fungi and some insects that make plants as their host.
charles Reply
what are microbes and what are their effects to humans
charles Reply
they are organism that cannot be seen with the naked eye
Angel
classify microorganisms.
Satarupa Reply
protozoa' bacteria' virus' algai' archea'
Cabdifitaax
protozoa
Ayesha
Thank you
Satarupa
bacteria,fungi, protozoa and virus
Angel
mutant having a requirement for a certain growth factor is called a(n)
Purushoth Reply
what is atome
Marie Reply
is the smallest part of any material that cannot be broken up by chemical means
Feisal
How does forest tree become sick
Emmanuel
Aseptate hyphae are seen in
lab Reply
yes
Ahmed
w
Ahmed
hello
Apdikrim
what is ADT
Feisal
hii
Salman
how does this work bro
Feisal
CHEMISTRY
Apdikrim
biology
Ahmed
I.m student
Ahmed
I.m question what is difference between arthropod and insect?
Ahmed
Arthropod is a large division of jointed-foot Invertebrates such as Insects, centipedes and others so Insect is a part of the division or the phylum
hilina
thanks
Ahmed
ur welcome
hilina
describe binary fission
Queen Reply
in which parent cell devides into two daughter cells
Iqra
single parent cell
Tean
who is the father of microbiology
Mary Reply
Antonie van Leeuwenhoek , he is father of microbiology and Louis Pasteur is father of modern microbioloy.
Arshad
Anton van leeuwenhoek ( He descovered bacteria in 1679)
Satarupa
what is the contriyo sachilden and sachwan in cell thoery
Iqra

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Source:  OpenStax, Microbiology. OpenStax CNX. Nov 01, 2016 Download for free at http://cnx.org/content/col12087/1.4
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