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92 Cards in this Set

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Obligate intracellular pathogens?
Chlamydophila pneumoniae, psittici, trachomatis (epithelium)

Rickettsia rickettsiae (vascular endothelium)

Coxiella burnetti (macrophages) - atypical ricketsia
Spore formers?
Bacillus anthracis

Bordetella pertussis

Clostridium botulinum, difficile, perfringens, tetani

Chlamydia (spore-like extracellular form)

Coxiella burnetti (spore-like extr form)
Nosocomial pathogens?
Enterococcus

Staphylococcus epidermidis

C. diff
Causes meningitis?
Group B Streptococcus (neonatal), Pneumococcus

Neisseria meningitidis (african meningitis belt), gonorrhoeae (rare)

Borrelia burgdorferi

Listeria monocytogenes (neonatal)

E. coli (K1 capsule, like group B strep)

Campylobacter fetus
Causes hemolytic-uremic syndrome (HUS)?

What are 3 hallmarks?
Shigella dystenteriae (shiga toxin)

EHEC - shiga like toxin

Thrombocytopenia, hemolytic anemia, renal failure
AB toxins?
Gprotein targeting toxins that incr cAMP:

ETEC Labile Toxin
Anthrax toxin (edema factor)
Bordetella pertussis

Botulinal neurotoxin (inactivates synaptobrevin -> flaccid paralysis)
Tetanis toxin (inactivates synaptobrevin, uses axons to go to CNS preventing GABA -> spastic paralysis)
Which bacteria are motile?
Borrelia burgdorferi (HIGHLY motile)

Treponema pallidum (HIGHLY motile)

Clostridium tetani (NOT other clostridia)

Vibrio cholerae

Campylobacter fetus, jejuni
Which bacteria are pyogenic?
Generally, Streptococci and Staphylococci
Gram + cocci
Streptococcus

Staphylococcus
Gram + rods
Listeria monocytogenes

Clostridia

Corynebacterium diptheriae

(Bacillus anthracis)
Gram - cocci
Neisseria - diplococcus!
Gram - rods
Shigellas

E. colis

Salmonellas

Campylobacter (spiral shape)

Legionella pneumophila

Yersinia

(Vibro cholerae - COMMA shaped)
Atypical shapes and gram stainings
Bordatella pertussis (gram neg coccobacillus)

Borrelia burgdorferi (gram neg, no LPS)

Treponema pallidum (gram neg spiral shaped)

H. pylori (gram neg helical shape)

Chlamydias (gram neg, hard to see on microscopy, obl intracellular)

Rickettsia (gram neg, can present in different shapes, intracellular)

Mycoplasma - no cell wall
Acid fast?
Mycobacterium tuberculosis, leprae, and non-tuberculosis strains
Obligate anaerobes?
Clostridia (botulinum, perfringens, diff, tetani)
Obligate/Strict aerobes?
Bordatella pertussis

Legionella pneumophilia

Mycobacteria
Facultative aerobes?
Vibrio cholerae

Listeria monocytogenes
Facultative anaerobes?
Corynebacterium diptheriae

Shigella

E. coli

Salmonella

V. cholerae (also aerobe?)
Which bacteria use capsules?
Streptococcus pyogenes, pneumococcus

Neisseria meningitidis

E. coli

Yersinia pestis

Klebsiella

Clostridium perfringens
difference between bactericidal and bacteriostatic antibiotics?
bactericidal inhibits growth irreversibly, bacteriostatic inhibits it reversibly (bacteria can resume growth.
Name the penicillin mechanism.
D-ala-D-ala analog that blocks activity of transpeptidase, which functions to crosslink peptidoglycan chains in bacterial cell walls. Penicillin also activates bacterial autolysins, leading to cell lysis which kills the bacterium.

Examples:
Penicillin G (benzylpenicillin)

Penicillin drugs have a beta-lactam ring which can be targeted by beta-lactamase, an enzyme that penicillin resistant bacteria have evolved. Pts are sometimes given a combination penicillin drug with beta-lactamase inhibitor (clavulanic acid, tazobactam).
What are beta lactamase resistant penicillins?
Methicillin, nafcillin, oxacillin
What are the synthetic penicillins?
Synthetic penicillins: amoxicillin, piperacillin (piperacillin active against pseudomonas, also often given as combo with tazobactam b lactamase)
What are cephalosporins? What prefix is used for these drugs?
Antibiotics with similar mechanism to penicillins. From fungi.

Prefix = Cef.

Classified into 3 generations, each one extending the # microbes it works against. Third generations can reach CNS to treat otherwise difficult to treat gram-neg meningitis.
Name a few 1,2,3 generation cephalosporins.
1st gen: Cefazolin
2nd gen: don't need to know
3rd gen: Ceftriaxone, Ceftazimide (reach CNS!)
4th gen: Cefepine
What transpeptidation inhibitor can be given to pts with penicillin allergy?
Aztreonam (monobactam drug)
What are carbapenems?
Another class of beta-lactam transpeptidation inhibitors.

Classic is Imipenem, which has broad distribution in body including CSF but is limited by dehydropeptidase in kidney. Usually given together with dehydropeptidase inhibitor cilastatin.
What are sulfonamides?
"Sulfa drugs." Interfere with bacterial folate synthesis disrupting DNA nucleotide availability.

Ex: Sulfamethoxazole

Often given with trimethoprim (TMP-SMZ), which inhibits dihydrofolate reductase, another enzyme involved in folate anabolism in bacteria. Syngergistically works against many pathogens.
How do quinolone drugs work and what are they?
Interfere with DNA synthesis by inhibiting DNA gyrase or Topo II.

Fluoroquinolones are a category of these with broad spectrum antibiotic activity. Also used in chemo.

Examples: Ciprofloxacin, Levofloxacin
What is metronidazole and what bacteria does it target?
Drug targeting anaerobic bacteria that exhibits DNA damage that leads to bacterial death. Anaerobes reduce it to highly reactive species inducing DNA damage.
What are aminoglycosides?
broad spectrum antibiotics that target bacterial protein synthesis.

TOXIC, have a small therapeutic index and can be nephro and oto toxic.

Example: Gentamycin, kanamycin

Work synergistically with penicillins.
What is tetracycline?
Ribosome inhibitor.

Broad antibiotic activity.

Doxycycline is a derivative.
What is Rifampin?
Inhibits RNA polymerase. Used to target mycobacteria.
Which antibiotics target protein synthesis/ribosome?
Aminoglycosides (streptomycin, gentamycin), tetracyclines, chloramphenicol, macrolides (azithromycin), streptogramins, linezolid
Antibiotics that target folate synthesis
Trimethoprim, sulfamethoxazole
Antibiotics targeting DNA synthesis
Fluoroquinolones (cipro, levofloxacin), metronidazole.
Antibiotics inhibiting peptidoglycan synthesis
Penicillins

Cephalosporins

Carbapanems

Vancomycin(gram+ only)

Fosfomycin, cycloserine, bacitracin
What is isoniazid
First line against M. tuberculosis. Inhibits mycolic acid, the wax coat in TB.
Bordetella pertussis
Gram - coccobacillus, non-motile

Human host only. Spread via aerosol. Contagious. Get by inhalation.

Multiplies on trachea/bronchi ciliated epithelium, doesn't invade. Bifunctional AB toxin similar to cholera - "diarrhea of mouth." Also dermonecrotic and tracheal cytotoxins. Slow Growth.

Mild in young adults. More severe "whooping" cough in children. vomiting, respiratory distress. most severe infants.

3 stages (catarrhal - "cold" dry cough, paroxysmal - intense cough and secondary pneumonia, convalescent - reduced sym)

Puts the P in DTaP vaccine.
Clostridium botulinum
Gram + rod strict anaerobe. Spore former.

Encounter in food, honey, wounds. Transmit via ingestion or skin lesion.

AB neurotoxin (sim to tetanus) -> inactivates synaptobrevin in peripheral nerves -> flaccid paralysis

polyvalent antitoxin.

High mortality 20%.
Clostridium difficile
Gram + rod spore former.

Causes pseudomembranous colitis. Associated with antibiotic use in hospital.

Toxin

normal flora in 3% adults.

Treat with vancomycin or metronidazole.
Clostridium perfringens
Gram + rod anaerobe spore former. Has capsule, rapid growth.

encounter thru birth, burns, contam meat, soil, wound/surgery.

Transmit via wound or ingestion, colonizes intestine.

Many toxins. Enterotoxin causes food poisoning. alpha and theta toxins.

Causes gas gangrene, anaerobic cellulitis, food poisoning self limiting.

Tx. antibiotics and debridment for gas gangrene. AB and drainage for cellulitis.
Clostridium tetani
Gram + anaerobe spore former. MOTILE.

Open wound contact with soil. cutaneous, punctures.

Tetanus AB toxin -> inactivate synaptobrevin -> spastic paralysis.

Lockjaw, respiratory paralysis, back and face muscle spasm.

T in DTP vaccine.

Treat with antitoxin, maintain airway, antibiotics. untreated 50% mortality.
Corynebacterium diphtheriae
Gram + rod (no spore, non-motile).

human throat carriers. Transmit via oral secretions. Colonizes pharyngeal epithelium.

Diptheria AB toxin. only expressed if bacteria infected with bacteriophage.

Cervical edema = Bull Neck.
Pharyngitis.
asphyxiation, irreversible cardiac and reversible neuro damage (muscle paralysis).

Tx. Antibiotics and horse antitoxin.

D in the DTP vaccine.
Vibrio cholerae
Gram - comma shaped. Highly motile. no spores.

Ingested from water. Colonizes epithelium of intestine.

AB cholera toxin causes incr cAMP and H2O efflux yielding watery rice diarrhea.

Tx: fluid replacement via drinking or IV. Antibiotics.

Death can occur rapidly without treatment.
Type III secretions
Salmonella enteriditis, typhimurium

Yersinia

Shigella

E. coli

Pseudomonas
Type IV secretions
Legionella, B. pertussis, H. pylori
Bartonella
gram neg bacilli causes Cat Scratch disease.
organisms where polysaccharide capsule central to pathogenesis
H. influnezae, S. pneuoniae, N. meningitidis.
Pathogens capable of intracellular growth or survival
Shigella, L. monocytogenes, Rickettsia

Coxiella, Chlamydia, M. tuberculosis, Salmonellae, Legionella pneumophila, Brucella, Yersinia.
Intracellular microbes that inhabit epithelial cells
Shigella (entry thru M cells)

Chlamydia trachomatis

Salmonella (gut epithelium)
Intracellular microbes that inhabit phagocytes
Listeria monocytogenes

Coxiella

M. tuberculosis (alveolar macrophages, create granulomas)

Legionella pneumophilia

Brucella
Intracellular microbes that inhabit endothelial cells
Rickettsia rickettsii
Brucella
Intracellular gram neg rod can grow in unactivated macrophages. Normally pathogens of cattle and sheep. Uncommon in US. Type IV secretion system.

exposure to livestock or unpasteurized milk.

Recurrent fever, anorexia, headache.
Bacteroides fragilis
gram neg rod obligate anaerobe of gut.

peritoneal infections.
Hemophilus influenzae
Gram neg rod.
Humans only host. Nasopharyngeal colonization + spread.

IgA protease. Carb capsule decreasing phagocytosis.

Sinusitis, otitis. Systemically bacteremia, meningitis, cellulitis. Damages endothelium, immune response causes collateral damage.
type B is very pathologic. Meningitis in young children.

Vaccination has decreased prevalence.

Tx with rifampin.
Similarities of H. influenzae and Streptococcus pneuomoniae (pneumococcus)
human only known host.
Colonizes nasopharynx, asymptomatic carrier state.
Invasive disease possible due to CAPSULE. These 2 along with N. meningiditis most imp agents of bacterial meningitis.
young ppl can't fight adequately as immune system not developed to attack carb antigens.
Diminished phagocytes can predispose.
Klebsiella (pneumoniae, oxytoca)
Gram neg rod. Enterobacterium.

NOSOCOMIAL Infections. diminished host defense and antibiotic use can lead to infxn by this often normal flora.

Antibiotic resistance, highly virulent, CAPSULE. K capsule antiphagocytic.

Respiratory inflection = currant jelly sputum.

UTIs.
Pseudomonas aeruginosa
Gram neg aerobe. Ultimate opportunist, formidable hospital acquired microbe. Versatile metabolically. Motile, pili adherent. Polysaccharide capsule.

Versatile pathogen, causes disease in many species. Disease in compromised patients can be deadly.

Found in soil, water, moist areas of human hosts. Hot tubs, contact lens solution.

Many toxins. Leukocidin, phospholypase C, exotoxin A like diptheria toxin.

bacteremia, intravascular catheter colonization, pneumonia, UTI, wound infection. Problem in burn patients.

Antibiotic resistant. USed to be common cause of death in CF pts. Still colonizes 90% CF pts by age 26. For serious cases ALWAYS combination therapy, can develop resistance during therapy.
Campylobacter jejuni and fetus
darting motility, gram neg spiral shaped, comma shaped. Commensal of pets and animals.

C. jejuni - gastroenteritis, food borne.
C. fetus - septicemia in compromised host

seasonality. Post infectious Guillan-Barre

tx: fluoroquinolones, macrolides
What species can cause reactive arthritis?
Campylobacter, Yersinia, Salmonella, Shigella
Helicobacter pylori
Facultative anaerobe, tightly coiled, gram neg. Slow grower

Only colonizer of stomach. More common in developing world.

has adhesins, urease, non inflammatory LPS, CagA virulence island, vacuolating cytotoxin - vacA.

implicated in gastritis/PUD -> gastric cancer. treating PUD by killing H pylori increases GERD.

hygeine hypothesis and asthma, inverse relationship to hpylori status.
Mycoplasma pneumoniae
Small, lacking cell wall, membrane = sterols.

Humans only known reservoir. Spread via aerosol droplets. Establish niche in upper respiratory epithelium. not tissue invasive, just blocks cilia, mononuclear infiltrate.

Fastidous, slow growth, self limited infection.

Leading cause of "atypical/walking pneumonia."
Legionella pneuoniae
Gram neg rod, aerobe, fastidious growth. type IV secretion system.

Aerosol from contaminated water. NO PERSON TO PERSON transmission. Colonizes alveolar macrophages. Has virulent and nonvirulent stages where infecting new macrophages or replicating, respectively. Regulated by amino acid starvation. Microabscesses.

"accidental" pathogen like Lyme.
Famous outbreak at Legionairres convention.

One of top 3 causes of CAP. Fever, malaise, non-prod cough, chest pain, rales early. Can be high mortality.

risk factors: age, chronic lung disease, smoking, immunosuppression
Brucella
Small non-motile gram neg rods, facultative intracellular, mostly macrophages.Mostly found in farm animals.

Can get from animals on unpasteurized milk product.

Similar to legionella, escapes lysosome making its own vacuole associated with ER.

Gets all thru the reticuloendothelial system. Gives rise to acute symptoms.
Enterococcus
Gram +
Normal GI flora
Nosocomial
Vanco resistance
endocarditis, bacteremia, UTI
Listeria Monocytogenes
Gram +, fac Anaerobe
Non-spore former, INTRACELLULAR INVASION
Specific cell-mediated immune response required to clear
oral-fecal (dairy, meat)
Lysteriolysin spread, host cell actin
Intestinal epithelium, M cells
Sepsis of unknown origin
Staphylococcus aureus
Gram +, cocci
Coag +, Clump Factor, Protein A
Superantigens (Epidermolytic - SSS; Enterotoxins (Heat stable - A-e, G); Enterotoxin F - TSST
Defense - catalase (H2O2), Coag, B-lactam, secretion of digestive enzymes
Localized - folliculitis, carbuncles
Deep - Abscesses, bacteremia, infection
Endocarditis
Staphylococcus epidermidis
Gram +, cocci
Coag -, clump F -, protein A -
skin, prosthetics
exopolysaccharide
Streptococcus pneumoniae
Gram +, diplococci, alpha hemolytic
Fastidious
Nasopharynx
Defense - IgA proteases, Capsule, Pneumolysin
Pneumococcal pneumonia - Changes PCN binding proteins to develop resistance
Streptococcus pyogenes group A
Gram +, cocci
M type and T type
Frequent recombination despite not being naturally transformable
Air-born, food-born
M protein, LTA, F protein - remains extracellularly
Hydrolytic enzymes (SpeB), Inflam response, TSS via SpeA (Spe = streptococcal pyrogenic exotoxin)
Streptococcus pyogenes group B
Gram +, cocci
Beta hemolytic
Normal GI flora, Vaginal Flora
Neonatal sepsis and meningitis
Bacteremia in adults
Staphylococcus aureus
Gram +, cocci
Coag +, Clump Factor, Protein A
Superantigens (Epidermolytic - SSS; Enterotoxins (Heat stable - A-e, G); Enterotoxin F - TSST
Defense - catalase (H2O2), Coag, B-lactam, secretion of digestive enzymes
Localized - folliculitis, carbuncles
Deep - Abscesses, bacteremia, infection
Endocarditis
Staphylococcus epidermidis
Gram +, cocci
Coag -, clump F -, protein A -
skin, prosthetics
exopolysaccharide
Streptococcus pneumoniae
Gram +, diplococci, alpha hemolytic
Fastidious
Nasopharynx
Defense - IgA proteases, Capsule, Pneumolysin
Pneumococcal pneumonia - Changes PCN binding proteins to develop resistance
Streptococcus pyogenes group A
Gram +, cocci
M type and T type
Frequent recombination despite not being naturally transformable
Air-born, food-born
M protein, LTA, F protein - remains extracellularly
Hydrolytic enzymes (SpeB), Inflam response, TSS via SpeA (Spe = streptococcal pyrogenic exotoxin)
Streptococcus pyogenes group B
Gram +, cocci
Beta hemolytic
Normal GI flora, Vaginal Flora
Neonatal sepsis and meningitis
Bacteremia in adults
Streptococcus Viridans
Gram +, cocci, alpha hemolytic
Oropharynx (N/F)
Dental carries, low virulence
Neisseria gonorrhae
Gram -, diplococcus
STD, perinatal
Women - spread up to fallopian tube (via sperm?)
Mucosal attachment - Pili, Opa proteins
Surviving mucosal immunity - iron acquisition (bind transferrin/lactoferrin), evade phagocytosis, serum resistance
Invasion of deep tissue - Porin, cellular entry, LOS, Sialylation
Antigenic variation and Phase variation (Pili, Opa, LOS)
C/P Women - Cervicitis, PID Men - Urethral discharge, Disseminated Gonococcal Infection (arthritis)
Concomitant Rx for Chlamydia
Neisseria meningitidis
Gram -, diplococcus, capsular
Serogroup A - major group in African meningitis belth
Serogroup B - no vaccine
Non-ciliated columnar epithelium - Nasopharynx
Minimal local - bacteremia - spread to CNS
Release high does LOS
Similar to N. gonorrhoeae
Rapid fulminant disease (septic shock, DIC, purpuric rash)
Salmonella typhimurium
Gram -, facultative Anaerobe
Chicken, eggs - person to person
Type III secretions
self-limiting 4-10 days
Gastroenteritis
Organism shed for several weeks after symptoms disappear
Salmonella typhi
Gram -, facultative Anaerobe
Bacteria remain within phagosome - no lysosome fusion
Gall bladder colonization (typhoid mary)
Enteric Fever (Typhoid) - slow onset, rose spots, intestinal hemorrhage and perforation
Vaccines - oral and parenteral; removal of gall bladder

typhoid mary
Shigella
Gram -, rod, facultative anaerobe
Lactose non-fermenters, intracellular invasion
Boydii, flexneri, sonnei no toxin
Dysenteriae produces virulent shiga toxin
Acid-resistance = low infectious dose
Hemolysin rarely invades past mucosa, self limiting
Shiga toxin (AB) - HUS
Hx - descending intestinal infection
Yersinia pestis
Gram -, rod
Large plasmid - resistance to inflammation and essential for virulence
Peptide capsule, protease w. plasminogen activator (increase invasiveness)
Aerosols, fleas
Bubonic plague, septicemic plague, pneumonic plague, biological warfare
Abs work
Mycobacterium tuberculosis
Acid fast stain, slow growing rods, aerobe
Fat (waxy coat) and Slow
Inhalation - prolonged close contact
Caseous necrosis, granulomas, hematogenous spread
90% primary infection contained, 10% reactivation
Organism can be dormant for years
Cavitation (caseous lesions liquify and spread)
PPD test, interferon gamma release assays
Multiple drug regimen for 6-9 months
Chemoprophylaxis for tx of latent TB
Mycobacterium leprae
Acid fast stain, grows in 9 banded armadillo
Found in endemic areas, human to human (not easily)
Infects cool areas of body
Pathology depends on host
Hansen's disease (Lepromatous - multi bacillary (no granulomas); Tuberculoid - pauci bacillary (granulomas))
multiple drug regimen for years or for life
Mycobacterium atypical
Acid fast stain, slow growing rods, aerobe
No human to human
marinum and fortuitum
Pulmonary infections
Direct probe culture
Tx often worse than disease (multi-drug regimen to avoid resistance 12-24 mos)
Borrelia burgdorferi
Like gram -, but no LPS
Highly motile (endoflagella between membranes)
Deer tick (northeast and great lakes)
Decorin protein, plasminogen, OspA (tick), OspC, antigen variation, lipoproteins, no toxins
LYME DISEASE
Treponema pallidum
Like gram -, but no LPS
Highly motile
Human mucous membranes, STD
Cross placenta
Syphilis
Chancre
No vaccine, tx PCN
Chlamydia pneumoniae
Obligate Intracellular, hardy spore-like EC form
Aerosols, epithelium
EB -> RB -> EB
Uses host ATP, inclusion bodies
Athersclerosis
Pneumonia (CAP)
Antibody not protective of subsequent infections
tx - doxy, erythromycin, azithromycin
Chlamydia trochomatis
Ocular secretions, sexual contact, epithelium
EB -> RB -> EB
Uses host ATP, inclusion bodies
Genital and neonatal infection syndromes - Accompanies gonorrhea 45% of time
Women - cervitis, fever and pelvic pain, urethritis, vaginal discharge; untreated - infertility, ectopic, preterm, abortion
Men - Epididymitis, proctitis, prostatitis, urethritis
Infants - mild pneumonia, purulent conjunctivitis
Lymphogranuloma venereum
Reiter's and Trachoma
tx - doxy, erythromycin, azithromycin
Rickettsia rickettsiae
Obligate Intracellular, NO hardy spore-like EC form
Endothelium
Arthropod vectors
Phospholipase (escape phagosome); host actin; cell lysis
Small hemorrhages, sepsis, vasculitic rash (palpable purpura)
Treat empirically - testing takes too long