Micro Flashcards
gram positive cell membrane component that induces IL-1 and TNF
lipoteichoic acid
teichoic acids trigger Gram positive shock as the cell wall is broken down -> fever, shock, DIC
gram negative major surface antigen that induces IL-1 and TNF
LPS = lipopolysaccharide (endotoxin) -> Lipid A
O polysaccaride is the antigen
bacteremia endocarditis IMPETIGO abscesses carbuncles FOOD POISONING TOXIC SHOCK syndrome Pneumonia
staph aureus
septicemia
endocarditis
wound infections
gram positive opportunist
staph epidermidis
UTI in newly sexually active young women
gram +
staph saprophyticus
gram + rod
normal oral flora & female genital tract
causes jaw abscesses with dental manipulation
drains by sinus tracts with yellow sulfur granules
Actinomyces
Tx: PCN
gram + bacillus
cutaneous (local), pulmonary (systemic), & oral/GI infections (local)
PA = protective antigen
EF = edema factor
LF = lethal factor -> inactivates MAP kinase -> cell death
PA + EF = Edema toxin
PA + LF = Lethal toxin (LT)
LT is more rapidly fatal
spores in dry soil or skins/coats of herbivores
*widened mediastinum from hemorrhage of thoracic lymph nodes in inhalation infection
cutaneous: ulcer with black eschar -> painless & necrotic
Bacillus anthracis
Tx: doxycyclin or ciprofloxacin
gram + rod
spore on rice cooked below boiling
nausea, vomiting, watery diarrhea (non-bloody)
Bacillus cereus
Tx: symptoms -> self-limiting
Board scenario: eating reheated fried rice
gram neg rod in oral flora of CATS
Causes bacillary angiomatosis (AIDS patient)
& cat-scratch disease (localized lymphadenopathy)
Bartonella henselae
Tx for bacillary angiomatosis: erythromycin or doxycycline
mediates adherence to indwelling catheters
glycocalyx
no cell wall but contain sterols
mycoplasma
gram neg rod
respiratory droplet spread
submucosal inflammation
Tracheal cytotoxin kills ciliated epithelial cells -> cough
whooping cough
3 stages to illness; tx with macrolides in catarrhal stage (runny nose, mild cough)
1. catarrhal (1-2 weeks)
2. paroxysmal stage (1-6 weeks) coughing +vomit
3. convalescent stage -> neuro damage or death
Bordatella pertussis
Vaccines:
DTap
Tdap -> booster
What stains glycogen and mucopolysaccharides?
PAS
used to stain Cryptococcus neoformans
India ink
stain for fungi
Silver stain
Acid-fast organisms stain
Ziehl-Neelsen (carbol fuchsin)
stains Chlamydia, Borrelia, Rickettsia, Trypanosomes, Plasmodium
Giemsa
agar used to grow fungi
Sabouraud
“Sab’s a fun guy!”
aerobe seen in burn wounds, complications of diabetes, nosocomial pneumonia & CF pneumonias
pseudomonas aeruginosa
spirochete transmitted by Ixodes tick Reservoir: mice Intermediate host: white-tailed deer bulls-eye rash causes Lyme disease
Borrelia burgdorferi
Symptoms: FAKE Facial nerve palsy Arthritis Kardiac block (AV block) Erythema migrans = bulls-eye rash Tx: doxycycline/ceftriaxone
Where are anaerobes normal flora?
GI tract
encapsulated bacteria
SHiNE SKiS Strep pneumoniae H flu Neisseria meningitidis E coli Salmonella Klebsiella pneumoniae group B Strep
patients with Chronic Granulomatous Disease (NADPH deficiency) have recurrent infections with what type of organisms?
catalase + Catalase degrades H2O2 before it can be converted by myeloperoxidase (bacteriocidal) Pseudomonas Listeria Aspergillus Candida E coli S aureus Serratia
gold pigment-producing bacteria
S “aureus” mean gold
produces blue-green pigment
pseudomonas
produces red pigment
serratia marcescens
“think maraschino cherry”
location of genes for EXOtoxins
plasmid or bacteriophage
Ex: tetanus, botulism, diphtheria
overactivates adenylate cyclase by disabling Gi
B pertussis
MOA: bind to 30s ribosomal subunit and prevent tRNA from binding to the A site
Used to treat Lyme disease, bacillary angiomatosis, anthrax
doxycycline = TETRACYCLINE
Adverse: photosensitivity, teeth discoloration
Other: minocycline
comma-shaped gram neg rod
most common cause of bacterial diarrhea in US
fecal-oral transmission
dogs
contaminated meat
watery foul-smelling diarrhea that becomes BLOODY
Campylobacter jejuni
commonly precedes GBS & reactive arthritis
“can’t see, can’t pee, can’t climb a tree”
rarely occurs with chlamydia infection
Reiter syndrome = reactive arthritis triad
treatment for chlamydia
azithromycin or doxycycline
BUT *** add ceftriaxone for gonorrhea
treat both partners
neonatal infections from chlamydia
conjunctivitis
pneumonia
Shiga-like toxin -> causes HUS
E coli (EHEC) 0157:H7 strain
dysentery
toxin causes enhanced cytokine release causing HUS
Shigella spp
toxin is Shiga toxin
pharyngitis with pseudomembranes in throat & severe lymphadenopathy
Corynebacterium diphtheriae
toxin is diphtheria toxin
watery diarrhea from heat-Labile toxin (LT) and heat-Stable toxin (ST)
ETEC = Enterotoxigenic E coli
spasticity, risus sardonicus, “lockjaw”;
toxin prevents release of GABA & glycine from Renshaw cells in spinal cord (inhibitory NTs)
Clostridium tetani
Toxin: tetanospasmin
Floppy baby
flaccid paralysis from toxin preventing release of ACh at NMJ
Clostridium botulinum
Toxin: botulinum toxin
most common cause of Meningitis Otitis media Pneumonia Sinusitis
Streptococcus pneumoniae
lancet-shaped diplococci
capsule
resistant to optochin
live in mouth
produces dextrans which form fibrin-platelet aggregates on damaged heart valves
strep sanguinis
major player in dental plaque
produces acid from carbohydrate fermentation -> allows invasion -> endocarditis
strep mutans
pharyngitis, Impetigo, Scarlet fever, necrotizing faciitis, Rheumatic fever
Strep pyogenes (group A strep) Note: impetigo commonly precedes glomerulonephritis
cold agglutinins
requires cholesterol for growth
walking pneumonia
Mycoplasma pneumoniae
Gram positive rods (4)
Clostridium corynebacterium Listeria Bacillus Mycobacterium (acid-fast)
test done for group B strep
CAMP test
colonize the gut
can grow in 6.5% NaCl and bile
nosocomial infection is vancomycin resistant
Enterococci = Group D strep
gamma hemolytic = no hemolysis
focal accumulations of virions or viral gene products
inclusion bodies
viruses replicate in the nucleus
DNA viruses
viruses replicate in the cytoplasm
RNA viruses
vesicular lesions of hands, feet, mouth & tongue
mild febrile illness
painful swallowing and vomiting
coxsackievirus A
The B virus can cause myocarditis and pleurodynia (devil’s grip)
negative monospot test
sore throat
hepatitis
generalized lymphadenopathy
CMV
Most typical cause of mononucleosis is EBV. Will see + monospot test in those patients.
Virulence factor for mycobacteria
Cord factor
Allows to form rope like cords which means that it can cause disease
It is two mycolic acids attached to trehalose
