week1day3 Flashcards
what are the three different types of anaerobes? which ones have catalase? and what are the examples?
1) obligate anaerobes-lack SOD and catalase - Clostridium, majority of perio bacteria
2) Facultative anaerobe - (grows with or w/o O2) - E.coli Streptococcus
3) Fastidious Anaerobes - May have low levels of SOD and may or may not have catalase - Bacteroides Fragilis
What is a consideration when selecting an antibiotic for B. fragilis?
It has beta-lactamases, and it confers the resistance to penicillin
What is a species of bacteriodes we studied? Is it pathogenic only?
B. fragilis. Its a “friendly” commensal that remains a normal resident until something changes in host (like a surgery). Then it will become pathogenic
What are the four gram- bacteria commonly found in infections?
Bacteroides, Prevotella, Porphyromonas, Fusobacterium
What is a species of bacteriodes we studied? Is it pathogenic only?
B. fragilis. Its a “friendly” commensal that remains a normal resident until something changes in host (like a surgery). Then it will become pathogenic
How does P.fragilis infect?
P. fragilis produces endotoxin. it has beta -lactamases. They confer resistance to penicillin.
What is the bacteria species of Prevotella that we studied? Where is it found?
P.melaninogenica, found in oral pharynx
which bacteria is a diagnostic marker for OSCC?
P. melaninogenica is found to predict 80%of oral squamous cell carcinomas
Which two bacterial species play a prominent role in adult periodontitis?
P.melaninogenica, P.intermedia
In which kinds of infections does P. melaninogenica become important?
oral and pulmonary infections (Asthma, COPD)
What species of porphymonas did we study?
P. gingivalis
What three types of disease is Fusobacterium nucleatum important in?
important in oral infections, lung abscesses, and other pulmonary infections, also ANUG
Which bacteria is associated with ANUG? What is unique about ANUG?
Fusobacterium nucleatum. ANUG is one of the only conditions that have 1 organism as a main player, since most other conditions are polymicrobial
What are the four different species of Clostridium? G- or g+?
C. Perfringens
C. difficile
C. Tetani
C. Botulinum
How does C. Perfringens cause the disease? What disease?
It causes GAS gangrene
It produces alpha toxin
What disease does C. Difficile cause? How?
Pseudomembranous colitis (inflammation in colon) Antibiotics associated diarrhea
What disease can C. Tetanus cause? How? get infected?
Tetanus. It releases neurotoxin -> muscle spasm/paralysis
Bacteria can be in soil, enters through a deep cut. Also via mother to fetus
What are the three types of C. Botulinum toxin?
1) Food - home canned goods
2) Wound - deep cut - through environment
3) Infant - bacterial spores
What are the three different actinomyces types? What are the treatment options?
Oral -normal flora, becomes pathogenic if trauma: like extraction
Cervicofacial -(sulfur granules)-> pyogenic abscesses
Abdominal - especially if ulcer
Treat with surgical draining and penicillin/ampicillin
What are the two main pathogenic Niseria species? What is a way we can differentiate between them?
Neisseria meningitidis -Ferments both glucose and maltose
and Neisseria gonorrhoeae - only ferments glucose
What are the two key virulence factors of Neisseria meningitis?
- Evade the immune system → IgA protease and polysaccharide capsule
- Overstimulate immune system → lipooligosaccharide
What does overstimulation of immune system caused by N. Meningitis manifest in?
Fever, Septic shock, Disseminated intravascular coagulation
Which bacteria would cause severe infection if someone’s complement doesn’t work?
N. Meningitis
What are the Neisseria gonorrhea key virulence factors?
- attach to mucosa = pili,.
- Evade immune system - IgA protease (like N. Meningitis)
What is encephalitis? Symptoms?
Inflammation of brain parenchyma (functional tissue of the brain, made of neurons and glial cells) → fever, altered mental status, seizures
What is meningoencephalitis? What are the clinical features?
Inflammation of both the meninges and the brain parenchyma
Fever, headache, altered menatal status, Seizures, focal neurologic deficits
How do the bacteria get into the CSF?
- hematogenous - travelled by blood
- direct spread ( like During a surgery)
what are the steps of hematogenous pathway of bacteria getting into the CSF?
- colonization -pili
- Invasion - IgA protease
- blood stream survival - evasion of complement pathway by capsular polysaccharide
- Meningeal invasion - cross their BBB→invade CSF→ multiply → meningitis
Three ways to test for meningitis? How does each work?
- Kernig’s sign - stiffness of hamstrings - can’t straighten the leg when bent 90 degrees
- Brudzinski’s signs - severe neck stiffness and hip and knees flex where neck is bent
- Direct sampling of CSF - puncture
Generally speaking, how does WBC count changes with bacterial meningitis vs viral vs chronic tb and vs Encephalitis
for bacterial - neutrophils.
for viral and all others - lymphocytes
Which common pathogen only infects Neonates and Adults over age of 50?
Listeria monocytogenes
Which common pathogen only infects children?
Haemophilus influenzae
Which 2 common pathogen infects children, young adults and Adults over age of 50?
Neisseria meningitidis and strep pneumoniae
what is the number 1 cause of meningitis in children and adults?
Strep pneumoniae
Why would you give corticosteroids for meningitis?
giving steroids before antibiotics is believed to reduce inflammation - still a debate
What are the prevention method against N. emningitidis before exposure, during and after?
pre: enhance immunity- vaccine
during - mask (droplet precaution)
post - Chemoprophylaxis for close contacts
certain bacterias and prevention methods (table)
Dont remember if we need it
What are the common risk factors of healthcare associated infections? What are some drug -resistant organisms?
- breakdown of membranes (Sx)
- foreign bodies (catheters)
- Inhibit reflexes (cough, gag)
- ab use
Drug resistant organisms: S. Aureus (MRSA)
p. aeruginosa and GNRs
enterococcus and candida
Where do the drug resistant pathogens come from? 3 things
Patient’s altered flora, healthcare workers, fomites (environment)
List top 5 HAIs and associated pathogens
- Pneumonia - S. aureus(MRSA), pseudomonas, enteric GNR
- Surgical site infection - MRSA, b-hemolytic streptococci
- Clostridium difficile colitis - C.difficile
- UTI - pseudomonas, enteric GNR, enterococcus
- catheter - related blood infection - S. Aureus and epidermidis, enterococcus, candida
What are the three ways of infection control and what are the nuances of using each? what are each used for?
- 70% Isopropyl and/or ethyl alcohol - not sporocidal! just for surfaces
- Dry heat sterilization - suitable for instruments
- Autoclave - effective against spores
