Bacterial meningitis project.

1. Bacterial
Meningitis
By Hannah Walker

2. Nervous System
Bacterial meningitis affects the nervous system,
The nervous system is made up of the central nervous
system (brain and spinal cord) and the peripheral nervous
system.
The nervous system is responsible for the sensory,
integrative, and motor functions of the body.
The meninges are the part of the nervous system that is
affected by bacterial meningitis.
Meninges are the tough membrane casings that encase the
brain and spinal cord.

3. History of Meningitis
● c.460-370BC Hippocrates
● 1661 Thomas Willis
● 1800 physicians termed this disease as ‘meningitis’ - combining ‘meninges’
with the suffix ‘itis’.
● 1805 Gaspard Vieusseux
● 1840 Africa
● 1887 Anton Vaykselbaum
● 1890 Heinrich Quincke

4. Causative Agents:
Bacterial meningitis can be caused by 4 different bacteria.
Neisseria meningitidis
Streptococcus pneumoniae
Haemophilus influenzae
Listeria monocytogenes

5. Neisseria meningitidis
● Morphology: Gram-negative diplococci
● Testing:
○ Cerebrospinal fluid, blood of nasopharyngeal
samples are taken.
■ Stained and observed for the Gram-
negative diplococci morphology
■ Taken and cultured on MTM or chocolate
agar
■ Tested by the oxidase test
■ A PCR test is used to id the pathogen
post antibiotic treatment
■ Susceptibility testing is needed.

6. Streptococcus pneumoniae
● Morphology:
○ Small
○ gram positive
○ flattened coccus
○ appears in end to end pairs
● Tests:
○ Grow on a BAP agar
○ Gram stain
○ Catalase test
○ Optochin tests
○ Bile solubility test.
○ Susceptibility testing

7. Haemophilus influenzae
● Morphology:
○ Gram negative
○ Coccobacillus
● CAP has no hemolysis
● Oxidase test should be positive,
● Check hemin and NAD as growth
requirements
● Susceptibility testing

8. Listeria monocytogenes
● Morphology:
○ Gram positive bacteria
○ Ranges in morphology from coccobacilli to
long filaments
● Tests:
○ Cold enrichment it is necessary to isolate the
microbe on a plated media
■ takes up to 4 weeks
○ Rapid diagnostic kits are available for direct
testing of cultures.

9. Incubation Period
Bacterial meningitis has an incubation period of 1-10 days after exposure.
We’re Ready!

10. Signs and Symptoms
Common signs and symptoms of bacterial meningitis are
● Photophobia
● Headache
● Painful or stiff neck
● Fever
● Increased number of white blood cells in the CSF
● There are additional symptoms unique to each bacterial infection, which will
be discussed later.

11. Pathogenesis of Meningitis
Neisseria meningitidis
● Disease progression
○ enters through the upper respiratory tract
○ passes into the surrounding blood vessels
○ then into the meninges
● The most serious complications
○ due to meningococcemia
■ causes vascular collapse,hemorrhage, and petechiae
■ occasionally becomes an overwhelming disease
● fevers above 104, chills,delirium, ecchymosis, shock, coma, generalized
intravascular clotting,cardiac failure, damage to adrenal glands, and death within a
few hours.
● 15% mortality rate.

12. Pathogenesis of
Meningitis
Streptococcus pneumoniae
● Disease progression
○ 25% of pneumococcal meningitis patients develop pneumococcal
pneumonia
○ More than 30% of the population carry Streptococcus pneumoniae in
there respiratory tract
○ Spread through droplets of infected individuals
○ It can become pathogenic and infect the respiratory mucosa, the
bloodstream, and then the meninges
○ It does not cause the petechiae associated with Neisseria
meningitidis.

13. Pathogenesis of Meningitis
Haemophilus influenzae
● Disease Progression
○ Portal of entry is the nasopharynx
○ Spread through droplets
○ can turn into severe meningitis, swelling of the meninges
○ and death

14. Pathogenesis of Meningitis
Listeria monocytogenes
● Disease Progression
○ Enters through consumption of contaminated food, water, or soil
○ Grows inside host cells and moves directly from an infected cell to a healthy
cell.
○ In elderly, immunocompromised, patients, fetuses, and neonates Listeriosis
can affect the
■ Brain, meninges, and result in septicemia or blood poisoning
■ Occasionally Listeriosis targets the heart
■ The death rate is 20%

15. Epidemiology of Meningitis
Neisseria meningitidis
● Passed through close contact with droplets
● Asymptomatic carriers
● Nonimmunine individuals are likely to become infected if in close quarters
with many people
○ eg. day care or college dorm
● In Africa a meningococcal epidemic sweeps through once a year.

16. Epidemiology of Meningitis
Streptococcus pneumoniae
● Spread by droplets
● Most prevalent in developing countries
● Most likely to occur in patients with underlying susceptibility such as
○ Alcoholism
○ Sickle cell disease
○ Low spleen function.

17. Epidemiology of Meningitis
Haemophilus influenzae
● Spread through water droplets
● Most common in countries without Hib vaccinations scheduled
● Babies and children under the age of 5 are most at risk for this disease

18. Epidemiology of Meningitis
Listeria monocytogenes
● Primarily in the soil or water
● Food is a secondary source of infection
● Listeria monocytogenes is more prominent in areas where pasteurization
practices are not properly maintained
● Most affected by this disease
○ Elderly
○ Immunocompromised
○ Patients
○ Fetuses
○ Neonates

19. Is bacterial meningitis treatable?
10%
death rate from bacterial meningitis, but if diagnosed and treated early enough,
most people recover

20. Treatment and Prevention
Neisseria meningitidis
● Vaccine: available for children over the age of 11
● Chemotherapy must be begun immediately upon suspicion of meningococcal
disease
○ Starting with Penicillin G
○ Then ceftriaxone,aztreonam, or chloramphenicol
● The patient may also need to be treated for certain symptoms of the disease
○ Intravascular clotting
● For people who came in contact with the patient, preventive treatment of
ciprofloxacin,rifampin, or vefriaxone may be needed.

21. Treatment and Prevention
Streptococcus pneumoniae
● Vaccines: 3 are available
● When a pneumococcal meningitis is suspected the patient should
immediately begin a treatment of vancomycin and ceftriaxone until the
antibiotic sensitivity of the particular strain of streptococcus is determined.
● If the bacteria is sensitive to penicillin G the treatment should be changed to
that.
● A steroid should be administered 20 min before antibiotic administration to
lessen the body's inflammatory response.

22. Treatment and Prevention
Haemophilus influenzae
● Hib vaccine beginning at age of 2 months.
● Hib infections are treated with intravenous third-generation cephalosporin
until antibiotic sensitivities become available.

23. Treatment and Prevention
Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae
These three bacterial diseases can additionally be prevented by
● washing your hands
● not to sharing droplets with other people through practices such as
○ covering your mouth when coughing
○ blowing/ sneezing into a kleenex

24. Treatment and Prevention
Listeria monocytogenes
● Vaccine:
○ No vaccine available for high risk groups
■ Eg. pregnant women and infants
○ Only vaccines available are live.
● Prevented by:
○ washing, refrigerating, cooking and pasteurizing foods
● When suspected antibiotic therapy
○ ampicillin,trimethoprim sulfamethoxazole, or meropenem

25. Conclusion
Bacterial Meningitis is not a disease you want to get.
If you get the symptoms of Bacterial Meningitis immediately go to your local ER
and seek treatment.

26. Sources
Calderón-González, Ricardo, et al. “Cellular Vaccines in Listeriosis: Role of the Listeria Antigen
GAPDH.” US National Library of Medicine, Frontiers in Cellular and Infection Microbiology,
2014, www.ncbi.nlm.nih.gov/pmc/articles/PMC3930854/.
Edwards, Holly. “The History of Meningitis.” Meningitis Research Foundation, 2017,
www.meningitis.org/blogs/the-history-of-meningitis.
“Haemophilus Influenzae: Causes and Transmission.” Centers for Disease Control and Prevention,
Centers for Disease Control and Prevention, 13 Feb. 2020, www.cdc.gov/hi-
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H.&text=influenzae%2C%20including%20Hib%2C%20disease%20occurs,are%20also%20at
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“Infectious Diseases Affecting the Nervous System.” Microbiology Fundamentals: A Clinical
Approach, by M. Kelly Cowan et al., McGraw-Hill Education, 2022, pp. 500–535.
Joseph Adrian L Buensalido, MD. “Haemophilus Influenzae Infections Treatment & Management:
Medical Care, Surgical Care, Consultations.” Haemophilus Influenzae Infections Treatment &
Management: Medical Care, Surgical Care, Consultations, Medscape, 26 June 2021,
emedicine.medscape.com/article/218271-treatment

27. Sources
“Meningitis Lab Manual: Id, Characterization of Strep Pneumoniae.” Centers for Disease Control and
Prevention, Centers for Disease Control and Prevention, 15 Apr. 2016, www.cdc.gov/meningitis/lab-
manual/chpt08-id-characterization-streppneumo.html.
“Meningitis Lab Manual: Id and Characterization of Hib.” Centers for Disease Control and Prevention,
Centers for Disease Control and Prevention, 15 Apr. 2016, www.cdc.gov/meningitis/lab-
manual/chpt09-id-characterization-hi.html.
Oliver, Drew. “Drew Oliver's Giant Microbes.” GIANT Microbes, 2021, www.giantmicrobes.com/.
Scott, Rich. “Bacterial Meningitis.” Florida Health, n.d., orange.floridahealth.gov/programs-and-
services/infectious-disease-services/epidemiology/_documents/bacterial-meningitis.pdf.