Micro- Bacteria Flashcards
Which part of GN and GP are the major cytokine inducers?
GN: lipid A- TNF, IL1
GP: LTA- TNF, IL1
Describe the cell membrane/ cell wall of mycoplasma
contains sterols
no cell wall
Describe the cell membrane/cell wall of mycobacteria
contains mycolic acid
high lipid content
What staining can be used to detect Legionella?
silver stain
What does Ziehl-neelsen staining detect?
acid fast organisms
Nocardia, Mycobacterium
What does india ink staining detect?
Cryptococcus neoformans
What does sabouraud agar culture?
Fungi
What does Thayer-martin agar culture?
Neisseria
What does Bordet-Gengou agar culture?
B. pertussis
What Tellurite agar culture?
C. diptheria
What does Lowenstein-Jenson agar culture?
M. tuberculosis
What does Eaton agar culture?
M. pneumonia
What does charcoal yeast extract agar culture?
Legionella
What are 3 examples of obligate anaerobes? What are some clinical features of them?
Clostridium, Bacteroides, Actinomyces
foul smelling, produce gas in tissue, dont treat with aminoglycosides
What are 2 examples of obligate intracellular bacteria?
Chlamydia, Rickettsia
What is the mechanism of Protein A and what organism expresses it?
Binds Fc region IgG, prevents opsonization and phagocytosis
S. aureus
What organisms express IgA protease? What is this important to colonize?
S. pneumo, H. flu, Neisseria
imp for colonizing resp tract
What does M protein do and what organism expresses it?
GAS
prevents phagocytosis
What toxin does C. diptheria produce? What is mechanism?
Diptheria toxin
Inactivation of elongation factor (EF-2)
What toxin does P. auruginosa produce? What is the mechanism
Exotoxin A
Inactivation of elongation factor (EF-2)
What toxin does shigella produce? What is the mechanism?
Shiga toxin
inactivate 60s ribosome- remove adenine from rRNA
HUS
What toxin does EHEC produce? What is the mechanism
Shiga-like toxin
inactivate 60s ribosome- remove adenine from rRNA
HUS
What toxins do ETEC produce? What are mechanisms?
Heat-labile toxin (LT)- incr cAMP (via adenylate cyclase)- Cl- secretion
Heat-stable toxin (LT)- incr cGMP- decr NaCL resorption
What toxin does vibrio cholerae produce? What is the mechanism?
Cholera toxin
incr cAMP by permanently activating Gs
incr CL- secretion
What toxin does Bordetella pertussis produce? What is the mechanism?
Pertussis toxin
incr cAMP by disabling Gi, impairs phagocytosis
What toxin does Clostridium tetani produce? What is the mechanism?
Tetanospasmin- protease cleaves SNARE prot
spacticity, lock jaw- act on inhibitory neuronotransmitters (GABA, glycine)
What toxin does Clostridium botulinum produce? What is the mechanism?
Botulinum toxin- protease cleaves SNARE prot
flaccid paralysis- act on stimulatory neuronotransmitters (Ach)
What toxin does Clostridum perfinges produce? What is the mechanism?
Alpha toxin
phospholipase- degrades tissue and cell membranes
gas gangrene, hemolysis
What toxin does S. pyogenes produce? What is the mechanism?
Streptolysin O
Degrades cell membranes
Lyses RBC
What superantigen does S. aureus produce? What is the mechanism?
TSST-1
Bring MHC II and TCR in proximity
What superantigen does S. pyogenes produce? What is the mechanism?
Exotoxin A
Bring MHC II and TCR in proximity
Compare generalized vs specialized transduction
Generalized- packaging event, lytic phage
specialized- excision event, lysogenic phage
Novobiocin sensitive
S. epidermidis
Optochin sensitive
S. pneumOnia
Bacitracin sensitive
S. pyogenes
group A strep
Catalase negative, a hemolytic (2)
S. pneumoniae
Viridans streptococci
GP, catalase negative, a hemolytic, bile insoluble
Viridans streptococci
GP, catalase negative, non-hemolytic (2)
How differentiate?
Group D (enterococcus- E. faecalis)- Grow in 6.5% NaCl Nonenterococcus (S. bovis)- Don't grow in 6.5% NaCl
b-hemolytic GP rod
Listeria
What GP organism is likely to cause abscesses? What is the mechanism?
S. aureus
forms fibrin clots around self (coagulase and other toxins)
What GP organism is likely to cause dental carries?
S. mutans
What GP organism makes dextrans? What does this cause?
S. sanguinis
endocarditis (via binding to fibrin-platelet aggregates)
What 4 diseases is S. pneumo the most common cause of?
MOPS Meningitis Otitis media Pneumonia sinusitis
CAMP test +
Group B strep
ELEK test
C. diptheria
What vaccine is given to prevent diphtheria?
Toxoid vaccine
Causes pseudomembranous pharyngitis with grayish-white membrane. What are other risks?
Diphtheria
myocarditis and arrhythmia
What is the only bacteria with a polypeptide capsule?
B. anthracis
contains D-glutamate
What is woolsorter’s disease?
inhalation of anthrax spores from contaminated wool
What food poisoning is associated with rice and past? What is toxin?
B. cereus
cereulide toxin- preformed- 1-5h after eating
Flu-like symptoms that rapidly progress to fever, pulm hemorrhage, mediastinitis, shock
pulmonary anthrax
What is the only gram positive organism to produce LPS?
Listera monocytogenes
What are the GP branching filament organisms? How differentiate?
Actinomyces- Anaerobe, not acid fast
Nocardia- Aerobe, acid fast
What causes amnionitis, septicemia, and spontaneous abortion and mild gastroenteritis in adults?
L. monocytogenes
What is the common source of Listeria?
unpasteurized dairy products and deli meats
What is the treatment for listeria?
Ampicillin
What is used to treat Actinomyces?
penicillin
What is used to treat Nocardia?
sulfonamides
What are the virulence factors of mycobacteria do?
Cord factor- inhibits macrophage maturation, induces release of TNFa
Sulfatides- inhibit phagoysosomal fxn
What is the prophylactic treatment for MAC?
azithromycin
What is the treatment for lepromatous vs tuberculoid Tb?
Lepromatous- dapsone, rifampin, clofazimine 2-5yrs
Tuberculoid- dapsone, rifampin, 6mo
Oxidase+, comma shaped, grows in 42 deg
Campylobacter
Oxidase+, comma shaped, grows alkaline media
vibrio cholerae
Oxidase+, comma shaped, produces urease
H. pylori
Gram Neg diploccoci, Maltose fermenter
N. menigitidis
Gram Neg diploccoci, non-maltose fermenter
N. gonorrhea
GNR, NLF, Ox+
Pseudomonas
GNR, LF (2)
Klebsiella, E coli
GNR, NLF, Ox- (4)
Shigella
Salmonella
Proteus
Yersinia
EMB agar- LF vs NLF
LF- purple/black colonies
Treatment of Neisseria
ceftriaxone (or penicillin G)
H. flu treatment
mucosal
menigitis
menigitis prophylaxis
mucosal: amoxicillin +/- calvulanate
menigitis: ceftriaxone
menigitis prophylaxis: rifampin
What causes epiglottitis?
H. flu
GN coccobacilli (2-4)
H. flu
Bordetella pertussis
pasteurelis
brucella
What type of pneumonia also has hyponatremia?
Legionella
Treatment of Legionella
macrolide or quinolone
What causes malignant otitis externa in diabetics?
P. arueginosa
What causes hot tub folliculitis?
P. aeruginosa
What is ecthyma gangrenosum? What causes it?
necrotic cutaneous lesion, P. aeruginosa
What is the treatment of P. aeruginosa?
aminoglycoside + extended spectrum penicillin
What is the E. coli virulence factor for pneumonia and neonatal meningitis?
K capsule
What is the E. coli virulence factor for cystitis and pyelonephritis?
fimbriae
What infection is common for burn patients
P. aeruginosa
What does EIEC cause?
Dysentery
invades intestinal mucosa- necrosis and inflammation
What does EPEC cause?
Diarrhea, often in childreen
no toxin, adhere to apical surface, flattens villi, prevent absorption
What type of E. coli does not ferment sorbitol?
EHEC
What does ETEC cause?
Travelers diarrhea (watery) heat-labile or heat-stable toxin
What commonly causes lobar pneumonia in acoholics and diabetics
Klebsiella
Where does S. typhi remain in carrier state?
Gallbladder
What type of inflammatory response is associated with shigella vs salmonella?
Salmonella- monocytic
Shigella- PMN
What diarrhea causing organism often causes Guillain-Barre and reactive arthritis?
Campy
Rice water diarrhea
Cholera
Can cause mesenteric adenitis; can get from pets
Yersinia enetrcolitica
Treatment for H. pylori
PPI+clarithromycin+ amoxicillin or metronidazole
What are the 3 spirochetes?
Borrelia (big)
Leptospira
Treponema
Flu-like sx, jaundice, photophobia with conjunctival suffusion
Leptosporosis
What is the cause of leptosporosis?
Animal urine in water
What is Weil disease?
severe form of leptosporosis
fever, hemorrhage, anemia (liver + kidney dysfunction)
What are the lesions associated with primary vs secondary vs tertiary syphillis?
Primary: chancre
Secondary: condyloma lata, rash on palms and soles
Teritary: gumma
Presents with saber shins, saddle nose, CNVIII deafness, mulberry molars
congenital syphillis
What is the natural reservoir of Borrelia burgdorferi?
Mouse
Presents with erythema chronicum migrans, flu-like symptoms, facial nerve palsy
Lyme disease
Presents as monoarthritis, AV nodal block, migratory polyarthritis, neuro
Lyme disease
Treatment of Lyme disease
doxycycline, ceftriaxone
What is the Jarisch-Herxheimer reaction?
Flu-like sx after starting antibiotics- killed bacteria release pyrogens
What organisms are carried by the Ixodes tick?
Anaplasmosis
Borrelia burgdorferi
What is associated with clue cells?
gardnerella vaginalis
What is associated with LAD with stellate granulomas with central necrosis?
Bartonella henselae (gram neg bacillus)
What is the treatment for Ricketssia and vector-borne illness?
doxycycline
Presents with a rash starting centrally that spreads out, sparing palms and soles
Typhus
What are the vectors for typhus?
Endemic (R. typhi)- fleas
Epidemic (R prowazekki)- human body louse
Presents as a rash starting at wrists and ankles, spreads to trunk, palms, soles
Rickettsia
Present with monocytes with morulae in cytoplasm (2), rash rare
Ehrilchiosis, anaplasmosis
Presents with pneumonia, rash rare, no arthropod vector
Q fever
Coxiella burnetti
Presents as small painless ulcers on genitals that progress to swollen, painful inguinal LN that ulcerate
Chlamydia trachomatis
Types L1, L2, L3
Treatment for chlamydia
azithromycin or doxycycline
What are the two forms of chlamydia?
Elementary bodies- enters cell via endocytosis, small and dense
Reticulate bodies- replicate in cell by fission
Causes blindness due to follicular conjuctivitis in Africa
C. trachomatis
Types A, B, C
Pneumonia presents with insidious onset, headache, nonproductive cough, patchy or diffuse interstitial infiltrate
Common in younger individuals
Myocplasma pneumoniae
What is the treatment for mycoplasma pneumonia
macrolide, doxycycline, flouroquinolone
positive for RBC agglutination, lysis of RBCs
mycoplasma pneumonia