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92 Cards in this Set
- Front
- Back
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Obligate intracellular pathogens?
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Chlamydophila pneumoniae, psittici, trachomatis (epithelium)
Rickettsia rickettsiae (vascular endothelium) Coxiella burnetti (macrophages) - atypical ricketsia |
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Spore formers?
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Bacillus anthracis
Bordetella pertussis Clostridium botulinum, difficile, perfringens, tetani Chlamydia (spore-like extracellular form) Coxiella burnetti (spore-like extr form) |
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Nosocomial pathogens?
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Enterococcus
Staphylococcus epidermidis C. diff |
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Causes meningitis?
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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 |
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Causes hemolytic-uremic syndrome (HUS)?
What are 3 hallmarks? |
Shigella dystenteriae (shiga toxin)
EHEC - shiga like toxin Thrombocytopenia, hemolytic anemia, renal failure |
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AB toxins?
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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) |
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Which bacteria are motile?
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Borrelia burgdorferi (HIGHLY motile)
Treponema pallidum (HIGHLY motile) Clostridium tetani (NOT other clostridia) Vibrio cholerae Campylobacter fetus, jejuni |
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Which bacteria are pyogenic?
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Generally, Streptococci and Staphylococci
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Gram + cocci
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Streptococcus
Staphylococcus |
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Gram + rods
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Listeria monocytogenes
Clostridia Corynebacterium diptheriae (Bacillus anthracis) |
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Gram - cocci
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Neisseria - diplococcus!
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Gram - rods
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Shigellas
E. colis Salmonellas Campylobacter (spiral shape) Legionella pneumophila Yersinia (Vibro cholerae - COMMA shaped) |
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Atypical shapes and gram stainings
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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 |
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Acid fast?
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Mycobacterium tuberculosis, leprae, and non-tuberculosis strains
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Obligate anaerobes?
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Clostridia (botulinum, perfringens, diff, tetani)
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Obligate/Strict aerobes?
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Bordatella pertussis
Legionella pneumophilia Mycobacteria |
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Facultative aerobes?
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Vibrio cholerae
Listeria monocytogenes |
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Facultative anaerobes?
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Corynebacterium diptheriae
Shigella E. coli Salmonella V. cholerae (also aerobe?) |
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Which bacteria use capsules?
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Streptococcus pyogenes, pneumococcus
Neisseria meningitidis E. coli Yersinia pestis Klebsiella Clostridium perfringens |
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difference between bactericidal and bacteriostatic antibiotics?
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bactericidal inhibits growth irreversibly, bacteriostatic inhibits it reversibly (bacteria can resume growth.
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Name the penicillin mechanism.
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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). |
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What are beta lactamase resistant penicillins?
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Methicillin, nafcillin, oxacillin
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What are the synthetic penicillins?
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Synthetic penicillins: amoxicillin, piperacillin (piperacillin active against pseudomonas, also often given as combo with tazobactam b lactamase)
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What are cephalosporins? What prefix is used for these drugs?
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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. |
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Name a few 1,2,3 generation cephalosporins.
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1st gen: Cefazolin
2nd gen: don't need to know 3rd gen: Ceftriaxone, Ceftazimide (reach CNS!) 4th gen: Cefepine |
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What transpeptidation inhibitor can be given to pts with penicillin allergy?
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Aztreonam (monobactam drug)
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What are carbapenems?
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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. |
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What are sulfonamides?
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"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. |
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How do quinolone drugs work and what are they?
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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 |
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What is metronidazole and what bacteria does it target?
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Drug targeting anaerobic bacteria that exhibits DNA damage that leads to bacterial death. Anaerobes reduce it to highly reactive species inducing DNA damage.
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What are aminoglycosides?
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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. |
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What is tetracycline?
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Ribosome inhibitor.
Broad antibiotic activity. Doxycycline is a derivative. |
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What is Rifampin?
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Inhibits RNA polymerase. Used to target mycobacteria.
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Which antibiotics target protein synthesis/ribosome?
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Aminoglycosides (streptomycin, gentamycin), tetracyclines, chloramphenicol, macrolides (azithromycin), streptogramins, linezolid
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Antibiotics that target folate synthesis
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Trimethoprim, sulfamethoxazole
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Antibiotics targeting DNA synthesis
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Fluoroquinolones (cipro, levofloxacin), metronidazole.
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Antibiotics inhibiting peptidoglycan synthesis
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Penicillins
Cephalosporins Carbapanems Vancomycin(gram+ only) Fosfomycin, cycloserine, bacitracin |
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What is isoniazid
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First line against M. tuberculosis. Inhibits mycolic acid, the wax coat in TB.
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Bordetella pertussis
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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. |
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Clostridium botulinum
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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%. |
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Clostridium difficile
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Gram + rod spore former.
Causes pseudomembranous colitis. Associated with antibiotic use in hospital. Toxin normal flora in 3% adults. Treat with vancomycin or metronidazole. |
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Clostridium perfringens
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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. |
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Clostridium tetani
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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. |
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Corynebacterium diphtheriae
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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. |
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Vibrio cholerae
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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. |
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Type III secretions
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Salmonella enteriditis, typhimurium
Yersinia Shigella E. coli Pseudomonas |
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Type IV secretions
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Legionella, B. pertussis, H. pylori
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Bartonella
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gram neg bacilli causes Cat Scratch disease.
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organisms where polysaccharide capsule central to pathogenesis
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H. influnezae, S. pneuoniae, N. meningitidis.
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Pathogens capable of intracellular growth or survival
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Shigella, L. monocytogenes, Rickettsia
Coxiella, Chlamydia, M. tuberculosis, Salmonellae, Legionella pneumophila, Brucella, Yersinia. |
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Intracellular microbes that inhabit epithelial cells
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Shigella (entry thru M cells)
Chlamydia trachomatis Salmonella (gut epithelium) |
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Intracellular microbes that inhabit phagocytes
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Listeria monocytogenes
Coxiella M. tuberculosis (alveolar macrophages, create granulomas) Legionella pneumophilia Brucella |
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Intracellular microbes that inhabit endothelial cells
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Rickettsia rickettsii
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Brucella
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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. |
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Bacteroides fragilis
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gram neg rod obligate anaerobe of gut.
peritoneal infections. |
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Hemophilus influenzae
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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. |
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Similarities of H. influenzae and Streptococcus pneuomoniae (pneumococcus)
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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. |
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Klebsiella (pneumoniae, oxytoca)
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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. |
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Pseudomonas aeruginosa
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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. |
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Campylobacter jejuni and fetus
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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 |
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What species can cause reactive arthritis?
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Campylobacter, Yersinia, Salmonella, Shigella
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Helicobacter pylori
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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. |
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Mycoplasma pneumoniae
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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." |
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Legionella pneuoniae
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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 |
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Brucella
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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. |
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Enterococcus
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Gram +
Normal GI flora Nosocomial Vanco resistance endocarditis, bacteremia, UTI |
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Listeria Monocytogenes
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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 |
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Staphylococcus aureus
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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 |
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Staphylococcus epidermidis
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Gram +, cocci
Coag -, clump F -, protein A - skin, prosthetics exopolysaccharide |
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Streptococcus pneumoniae
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Gram +, diplococci, alpha hemolytic
Fastidious Nasopharynx Defense - IgA proteases, Capsule, Pneumolysin Pneumococcal pneumonia - Changes PCN binding proteins to develop resistance |
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Streptococcus pyogenes group A
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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) |
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Streptococcus pyogenes group B
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Gram +, cocci
Beta hemolytic Normal GI flora, Vaginal Flora Neonatal sepsis and meningitis Bacteremia in adults |
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Staphylococcus aureus
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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 |
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Staphylococcus epidermidis
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Gram +, cocci
Coag -, clump F -, protein A - skin, prosthetics exopolysaccharide |
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Streptococcus pneumoniae
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Gram +, diplococci, alpha hemolytic
Fastidious Nasopharynx Defense - IgA proteases, Capsule, Pneumolysin Pneumococcal pneumonia - Changes PCN binding proteins to develop resistance |
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Streptococcus pyogenes group A
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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) |
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Streptococcus pyogenes group B
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Gram +, cocci
Beta hemolytic Normal GI flora, Vaginal Flora Neonatal sepsis and meningitis Bacteremia in adults |
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Streptococcus Viridans
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Gram +, cocci, alpha hemolytic
Oropharynx (N/F) Dental carries, low virulence |
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Neisseria gonorrhae
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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 |
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Neisseria meningitidis
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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) |
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Salmonella typhimurium
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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 |
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Salmonella typhi
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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 |
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Shigella
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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 |
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Yersinia pestis
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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 |
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Mycobacterium tuberculosis
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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 |
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Mycobacterium leprae
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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 |
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Mycobacterium atypical
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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) |
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Borrelia burgdorferi
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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 |
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Treponema pallidum
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Like gram -, but no LPS
Highly motile Human mucous membranes, STD Cross placenta Syphilis Chancre No vaccine, tx PCN |
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Chlamydia pneumoniae
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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 |
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Chlamydia trochomatis
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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 |
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Rickettsia rickettsiae
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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 |
