micro review Flashcards
to help us destroy the shit out of this exam
If a bacteria doesn’t have a cell wall (no peptidoglycan) like Mycoplasma and Ureaplasma, what Abx will these bact be resistant to?
Beta-lactams (which inhibit peptidoglycan synthesis)
Does sporulation occur in Gram Pos or gram neg bact?
GP: aerobic bacillus, anaerobic clostridium GN: no
which cause of meningitis can be treated with a chemoprophylaxis?
N. meningitidis
defining components of Bacteria (4)
- lack membrane bound organelles 2. reproduce by division (binary division for the most part (but not chlamydia!)) 3. vary in their need for O2 (obligate aerobe, facultative anaerobe, obligate anaerobe) 4. vary in shape (bacillus, coccus, spirochete/spirillum)
Primary Syphilis: timing: manifestation: Number and location of treponemes:
timing: approx 3 wks post exposure manifestation:chancre which are hard like cartilage with a raised border near anus, penis, vagina or mouth. PAINLESS Treponemes: many at site of innoculation
Normal age/population of people with S. agalactiae meningitis
New born (think Group “B” strep for baby), coming from mother’s birth canal, and the elderly
the hematogenous spread of the bacteria that cause meningitis requires protection from what two parts of the innate immune system?
- phagocytosis 2. complement
3 stages of Syphilis (with symptoms and levels of measurable treponemes
- Primary: chancre which are hard like cartilage with a raised border near anus, penis, vagina or mouth. PAINLESS -many Treponemes at site of innoculation Secondary stage: Rash ON HANDS AND SOLES OF FEET that is scaley, mucosal lesions, lymphadenopathy - many treponemes widespread Tertiary: some people are asymptomatic (but a serological test would still show it’s there), others get neurosyphilis, cardiovascular syphillis (prob w/aortic valves) and gumma at many sites -few treponenes that are widespread
Mycoplasma and Ureaplasma are unique bacteria in that they…
don’t have a cell wall (ie no peptidoglycan) or outer membrane
Secondary Syphilis: timing: manifestation: Number and location of treponemes: how many people get it compared to primary?
timing: 2-24 weeks manifestation: Rash ON HANDS AND SOLES OF FEET that is scaley, mucosal lesions, lymphadenopathy Number and location of treponemes: many, widespread how many people get it compared to primary: 50%
are teichoic/lipoteichoic acids in gram pos (GP) or gram neg (GN)
teichoic/lipoteihoic acids: - GP: yes -GN: no
Bacterial Meningitis:
protein levels:
glocose levels:
primary WBC
other:
protein levels: VERY elevated glocose levels: reduced primary WBC: PMNs other: a gram stain shows up 60% of the time (ie you can see there are bacteria in the CSF)
Fungal Meningitis
protein levels:
glucose levels:
primary WBC:
protein levels: more elevated than viruses, not as elevated as bacteria glocose levels: down like bacterial meningitis primary WBC: elevated lymph *looks a lot more like bacterial meningitis than viral except for the type of WBC in CSF (lymph vs PMN)
why can’t chlamydia be seen on a gram stain?
because they have an outer membrane but no peptidoglycan
which bacteria are acid fast?
Mycobacteria– they have a thick, waxy cell wall!
the 3 infections shared by Chlamydia Trachomatis and N. gonorrhoeae in adults? What do they cause in new borns?
in adults: urethritis, cervicitis and PID– CT and GC in adults are clinically indestinguishable in newborns: conjunctivitis (both), pneumonia (Gonorrhoeae only)
LPS (O antigen of bacterium)/endotoxin in gram pos. vs gram neg bact.
LPS/endotoxin: GP: no GN: yes
porins present in gram pos vs gram neg bacteria?
porins: GP: no GN: yes– these regulate what can get into GN bact
what is most likely the cause of meningitis in a 3 yo from a developing country if the CSF shows small, pink, gram negative coccobacilli organisms?
HIB
is bacterial or viral meningitis more common? which is more severe?
viral is more common, bacterial is more severe
most likely cause of meningitis in a 7 yo if it’s gram positive dipplococci?
strep pneumoniae (pneumococci)
preventative measures for meningitis from S. agalactiae (group B strep)
screening, perinatal txt
general population, age of people who get meningitis from N. meningitidis?
10-college aged students/people in the military/dorms, less frequently in 3-10 yr olds
C. throcamatis: gram stain: morphology: replication: how do we identify CT in the lab?
gram stain: not visible bc no peptidoglycan replication: obligate IC replication because it doesn’t make it’s own ATP. Identify CT in the lab via: PCR
outer membrane present in gram pos vs gram neg bact
outer membrane: -GP: no -GN: yes
Tertiary Syphilis-
timing:
morphology:
amount and location of treponemes:
how many people get it compared to primary syphilis:
timing: 3-30 yrs
morphology: symptomatic latency, neurosyphilis, cardiovascular syphilis (problems with aortic valves), Gumma in many sites (which don’t cause trouble)
amount and location of treponemes: few, widespread
how many people get it compared to primary syphilis: 2/3rds of the people with secondary syphilis get tertiary, and 1/2 of the people with primary syphilis get secondary, so about 33% of people get tertiary syphilis
N. Gonorrhoeae– gram stain: shape: replication
gram negative shape: diploccocus (looks like N. meningitidis) replication: intracellular
Conjugation: how does it work and what’s associated with it?
works by: donation of plasmid using sex pilus assoc. with: antibiotic resistance spread among isolates
transduction: how does it work and what’s assoc with it?
works by: lysogenic bacteriophage in bacterial genome associated with: exotoxins
what cause of meningitis is often food borne (meats and soft cheeses)?
L. monocytogenes
Capsules or flagela in gram pos and/or gram neg bact?
some in both GP and GN
Gram positive (GP) Cell envelopes vs gram neg (GN) cell envelopes: Peptidoglycan: teichoic/lipoteihoic acids: Outer membrane: LPS/endotoxin: Porins: Sporulation: Capsule, flagella:
Peptidoglycan: - GP: thick (50+ layers) -GN: thin (1-2 layers) teichoic/lipoteihoic acids: - GP: yes -GN: no Outer membrane: - GP: no -GN: yes LPS/endotoxin: - GP: no -GN: yes Porins: - GP: no -GN: yes Sporulation: - GP: aerobic bacillus, anaerobic clostridium -GN: no Capsule, flagella: - GP: some -GN: some
general age/population of people who get meningitis from L. monocytogenes
Elderly (immunocompromised) and some new borns (vertical transmission from mother’s birth canal)
general age/pop of people with meningitis from HIB?
3 months-10 yrs. Usually in developing countries that don’t have a vaccine, essentially eradicated in the states
what is most likely the cause of meningitis in a new born if it’s gram positive cocci in chains?
Group B strep (S agalactiae)
what makes the outerm membranes of spirochetes (eg T. Pallidum) unique?
no LPS in the outer membrane
urethritis
painful burning on urination and pus discharge from penis
General features of meningitis
- Meningeal irritation (painful/stiff neck exacerbated by moving the meninges)– SPECIFIC TO MENINGITIS 2. acute onset of fever and severe headache (more general)
3 types of meningitis that can be prevented with a conjugate vaccine?
HIB, S. pneumoniae, N. meningitidis
most likely cause of meningitis in a 22 yo whose CSF showed gram negative dipplococci whose sides are flattened next to each other (look like coffee beans)
N meningitidis
most likely cause of meningitis in a 65 yo whose CSF shows gram positive bacilli?
Lysteria monocytogenes
Which 3 types of meningitis are associated with person to person spread and pharyngeal colonization?
- HIB 2. S. pneumoniae 3. N. meningitidis
what is the main virulence factor for S. peumoniae, HIB and N. meningitidis? How do we try to deal with this virulence factor?
an antiphagocytic capsule. We try to deal with it by giving conjugate vaccines that stimulate the production of anti-capsule Abs even in young children who are not otherwise competent to make Ab response to T-cell-independent antigens
3 mechanisms for genetic exchange in bacteria
transformation, conjugation and transduction
general age/population of people with meningitis from S. pneumoniae?
3 months -10 yrs old in particular, and the elderly, but you can get it at any age older than 3 mo
which two causes of meningitis are often caused by vertical transmission?
Group B (strep agalactiae) L. monocytogenes
generally, men with CT or GC present… ? women?
men… usually asymptomatic, or urethritis. Women are usually asymptomatic
Viral meningitis: protein levels: glocose levels: primary WBC other:
Viral meningitis: protein levels: normal or a little elevated glocose levels: normal primary WBC: increased lymph other: no gram stain (bacteria don’t show up on the gram stain)
transformation: how does it work, and what’s associated with it?
works by: uptake of free DNA in EC environment (ie from dead bacterial cells) associated with: Abx resistance and antigenic variation
peptidoglycan presence in Gram Pos (GP) vs gram neg (GN) bacteria
Peptidoglycan: - GP: thick (50+ layers) -GN: thin (1-2 layers)
