29 Microbiology: Bacterial CNS Infections Flashcards
CSF analysis
- These are vials of CSF
- Which one is healthy?
- Which one is most likely an infection?
- What is the reason for the brown hue in the left vial?


Pneumococcal Meningitis
- This is an acute purulent type of meningitis. What commonly occurs before patients present with meningitis?
- How does this type of meningitis relate to recurrent/chronic meningitis?

Meningococcal Meningitis: Characteristics
- What is the present on the skin of infected patients?
- Does the skin blanch?
- When do these lesions erupt?
- What can occur if they erupt?

GBS (S. agalactiae)
- Are they gram (+) or gram (-) ?
- How would you describe what these bacteria look like?
- When does the baby usually get affected?
- How often does colonization cause infection in neonates?
- GBS (+) adults usually have what kind of conditions?


Causative Agents: Streptococcus pneumoniae
- What time year are these types of infections more common?
- What 2 populations have a greater risk of infection and subsequent development of meningitis?
- What is important to know about how the microbiome relates to asymptomatic carriers of this pathogen?

Adult Signs and Symptoms
- What is considered the classic triad of bacterial meningitis in adults?
- Besides the triad, what other signs and symptoms can patients have?

Treatment and Prevention: Meningococcal Meningitis
- What is the drug of choice?
- What can you use if the above answer is contraindicated?
- What should be done with close contacts?
- What kind of vaccine is used for all the infective strains, aside from B, in children, adolescents, or high-risk people?

Meningococcal Meningitis: Epidemiology
- What animals carry this bacteria?
- What part of the body is usually colonized first?
- How does infection occur?

Meningococcal Meningitis: Patient Groups
- Infants
- Why might this group be difficult to Dx with early-stage infections?
- What symptoms/signs does later stages of infection have?
- Older children and adults
- What conditions might this population have?

Hib Meningitis: Treatment and Prevention
- What can be detected in the CSF in more than 90% of cases?
- How can this give you prognostic information?
- How many Hib conjugate vaccines exist?

Seasonality
- All of these organisms are associated with meningitis that occurs in the winter?
- Which one is associated with late winter and early spring infections that occur in infants?
- Which one is associated with both winter and summer infections that affect newborns? When does this same organism have a high incidence of affected predisposed adults? Does it affect healthy adults?
- Which organism is associated with infants/toddlers as well as the elderly?
- Which one is associated with infants and adolescents?


Meningitis
- What occurred between 1986 and 1995 that saw a major shift in the common bacterial causes of meningitis?
- What did this do the incidence of Group B Strep and Strep. pneumoniae?

Diagnosis: S. pneumonia
- How do you presumptively ID this bacteria?
- How do you confirm your ID?
- What happens to the bacterial cells with this test?
- What kind of hemolysis does S. pneumoniae have?
- How do you observe the capsules associated with this bacteria?

Dx of Bacterial Meningitis
- What must be done in order to dx this?
- What 3 other basic types of tests can you do to compliment the above procedure or if the above procedure cannot be done?

Early vs Late Onset GSB Neonatal Infections
- Occurrence
- Which one is more common
- Time
- When does early onset occur
- When does late onset occur?
- Pneumonia
- Does this occur in early or late onset?
- Bone/Joint Infections
- Does this occur in early or late onset?

Prevention and Prognosis of Neonatal Meningitis
- Prenatal screening can be done to see if pregnant women are infected.
- What organism are mothers screened for?
- When during pregnancy should they be screened?
- What kind of mortality rate does this condition have?
- What is life like for survivors?

Hib Meningitis pathogenesis
- Where are two types of infections common right before getting meningitis?

Meningococcal Meningitis:: Epidemiology
- What are the 4 determinants for infection susceptibility in humans?

Clinical Manifestations of Listeria monocytogenes
- What are the 2 most dangerous manifestations?
- Neonatal Infections
- What are the devastating results of these type of infections?
- Adult Infections
- What 2 types of unrelated conditions does Listeria monocytogenes commonly cause meningitis in?
- Encephalitis is a classic feature of this.
- Where in the brain does it occur: brainstem, diencephalon, or telencephalon?

Pathogenesis of Listeria monocytogenes
- People who ingest contaminated foods may become infected with Listeria monocytogenes
- What type of cell must first be penetrated? (known as invasion factor)
- In healthy hosts
- What occurs?
- In compromised hosts?
- Where does this organism replicate?
- What occurs first before meningitis can occur?

Tx of Bacterial Meningitis
- What must be done right away in order to have the best possible outcomes?
- What drug is used for pneumococcal meningitis?

Pneumococcal Meningitis
- What are the 4 main predisposing conditions for this?

Pneumococcus
- Capsule
- What cellular process does this inhibit?
- How does it evade opsonization?
- Why is this a focus for medical scientists?
- Autolysin
- What does this process release from the bacteria?
- Why does it do it?
- Pneumolysin
- What does this form in host cells?
- What does it activate?
- Besides the above, what are the other 3 main virulence factors of this organism?

Meningitis: Haemophilus influenza pathogenesis
- What kind of capsule do they have, and how what form of immunity does this help them avoid?
- What are the 2 molecules that virulent strains produce?
- These bacteria infect the nasopharynx. What structure is required for this?
- What is LOS?

Meningitis and Neonates
- What are the 8 common signs/symptoms of bacterial meningitis in this age group?
- E. coli related meningitis is rare in this age group. What are the 2 common pathogens that cause neonatal meningitis?

Prions
- What are they?
- What are some diseases they cause in humans?
- What do they cause in deer and why is this concerning?

Meningitis
Besides vaccines, what else has caused a major decrease in the incidence of meningitis?

Seasonality
- What are the 3 main community-acquired bacterial causes of Meningitis?
- What are the 3 main hospital-acquired bacterial causes of Meningitis?

Meningitis: Epidemiology
- About 70% of cases of meningitis occurs in what 2 age groups?
- In adults
- What is the fatality rate?
- What percent of patients end up with permanent brain damage?
- In children
- What are the most common long term effects of meningitis?
- US and Global
- What is the incidence of meningitis US and worldwide, and what is the fatality rate world-wide?

Listeria monocytogenes
- This organism posses an LPS-like surface component. What about it’ cell wall structure would indicate that it does not have true LPS?
- Listeriolysin O (LLO)
- What 3 abilities does this virulence factor have?

Causative Agents: Streptococcus pneumoniae
- Is this gram (+) or gram (-)?
- What is unique about their shape?
- What is important to remember with meningitis and how common these types of infections are?
- What kind of hemolysis do they have, and what does this do to the color of their colonies?
- These bacteria have optochin sensitivity. What does that mean?
- What kind of strains are virulent?


Neonatal Causative Agents: E. Coli
- Are these gram (+) or gram (-)?
- What do they look like?
- What kind of strains are associated with meningitis?
- Are these common or rare?
- If this organism is the cause of meningitis an adult, what probably recently happened to the adult?

Prevention of S. pneumoniae infection
- Who usually gets the 23-valent capsular polysaccharide vaccine?
- Who usually gets the 13-valent capsular polysaccharide vaccine?

Pathogenesis of Bacterial Meningitis
- What are the steps that lead to the Edema, increased ICP, and altered blood flow associated with bacterial meningitis?

Hib Meningitis pathogenesis
- Normal Colonization
- What structure is first colonized?
- What layer of cells is penetrated?
- What must bacteria enter in order to reach the CNS?
- What part of the brain is seeded first with bacteria?

Meningococcal Meningitis: Dx
- What can of stain should be performed?
- What types of agar will be positive for this bacteria if infected blood or CSF is plated on it?
- What can be detected in the CSF?
Chocolate agar is used for growing fastidious respiratory bacteria, such as Haemophilus influenza and Neisseria meningitidis

Neonatal Meningitis
- What are the 2 Neonatal Factors that contribute to this?
- What are the 5 main Maternal Factors that contribute to this?

Meningococcal Meningitis: Neisseria meningitis
- Are these bacteria gram negative or gram positive?
- What do they look like?
- Do they have a capsule?
- Which strains are the most important to remember?
- Which strain had a new vaccine just recently made?


Meningitis: Haemophilus influenza
- Are these bacteria gram negative or gram positive?
- Are they mobile?
- What is special about their capsule, and why does this make it difficult to ID serotypes?
- What kind of hemolysis doe they have?

Causative Agents: Listeria monocytogenes
- Are these bacteria gram (+) or gram (-)?
- What shape do they have?
- How do they move?
- What kind of preparation can you see this type of motility?
- What is notable about the temperature that they can grow in?
- How does this make them an excellent foodborne pathogen?
- They are a facultative intracellular pathogen. What does that mean?


Treatment: S. pneumoniae
- What is the first line treatment?
- If the strain is resistant to the answer to number 1, what can you use?
- What medication is used in children, and why?
- If the strain is resistant to the answer to number 3, what do you use?

Dx of GSB infection
- What factor is would a lab test find to confirm a GSB infection?
- What does this look like when plated, compared to S. aureus?
- What kind of lysis occurs to RBC’s when plated with GSB?
- What does the test for the above factor require in order to be conduted?
