S. aureus and S. pyogenes both can cause Impetigo. However, Erysipelas can only be caused by S. pyogenes
Impetigo/Erysipelas: Signs and symptoms
Impetigo: read patches ->pus-filled vesicles ->honey colored crust, itching. If S. pyogenes spreads to LN it can cause reddening of the skin (distinct margins), swollen LN, fever, and leukocytosis, which are signs of Erysipelas.
M protein: on the outer membrane, destabilizes complement system, reduces phagocytosis. Capsule: contains hyaluronic acid (looks like host, prevents attack). Pyrogenic toxins: simulates macrophage and T cell cytokine release -> fever, rash, shock.
Impetigo/Erysipelas: Pathogenesis, transmission
Broken skin/scratch, fomites, person-to-person, high in children 2-5 yrs old (b/c they put their hands everywhere)
Impetigo/Erysipelas: Diagnosis/treatment, complications
Clinical, bacteria and WBCs in vesicle (different than scalded skin syndrome). Washing, Penicillin, topical drugs are good if it works (don't kill normal flora). Bacteremia, acute glomerulonephritis (antigen-antibody complex in the kidney) -> inflammation, blocking
Necrotizing fasciitis: pathogen/s, pathogenesis, transmission
S. aureus, S. pyogenes. Destroys fascia and fats. Person to person, iatrogenic (from a medical procedure).
Necrotizing fasciitis: virulence
Deoxyriboneucleases: degrade DNA. Streptokinase: dissolve clots. Hyaluronidase: separates cells. Streptococcal pyrogenic exotoxins: fever, rash, inflammation (from T cell proliferation), B-cell suppression. Streptolysin S: pore forming cytotoxin (kills host cells)
Necrotizing fasciitis: signs and symptoms
Intense swelling or pain at infection. Skin distended and discolored, hot sunburn appearance, fever, nausea, malaise. Organ failure, confusion (from bp drop)
Necrotizing fasciitis: diagnosis/treatment, complications
Clinical (excessive pain from injury, fast spread). Amputation/debridement, Clindamycin and penicillin together (83% effective). Death rate is 50%, chicken pox introduces an increased risk for infection.
Acne: pathogen/s, virulence
Propionibacterium acnes (85%), S. aureus. Utilize sebum as nutrient source.
Acne: signs and symptoms, diagnosis, treatment
red, hard bumps on face shoulders and back. Benzoyl peroxide kills bacteria (dries skin), Retinoic acid: inhibits sebum production, Doxycycline (high concentrations in the skin)
Acne: complications of disease and treatments
Secondary infections. Retinoic acid use may cause intestinal bleeding and birth defects. Long-term antibiotic use reduces normal flora -> selects for resistant organism.
Acne: transmission, pathogenesis
Normal flora. Infects sebaceous glands, associated with hair follicles -> inflammatory response, high testosterone causes excessive oil production and increases infection. Cytic acne ruptures sebaceous glands and leads to scarring.
Cat Scratch: pathogen, virulence, pathogenesis, transmission
Bartonella hensele. Endotoxin (lipid A). Local introduction, dissemination to adjacent LN. 40% of kittens carry B h, fleas transmit between kittens. Young kids and vets are likely to get this.
Cat scratch: incubation period, signs and symptoms
7-12 days. Pimple-like bumb at scratch site for 1-4 weeks, enlarged LN near scratch. Fever in 30% of cases. Serological (antibody/antigen), clinical. Azithromycin, clean scratches thoroughly.
Cat scratch: complications
dissemination to organs, encephalitis, endocarditis.
Pseudomonas aeruginosa: people infected, signs and symptoms
Burn victims, CF patients (difficult for antimicrobials to work b/c of the thick mucus), diabeites, AIDS. Endocarditis, septicemia. Eye, ear, bone, joint, UTI, CNS infections. Caused by catheters, implants. Causes a blue/green pyocyanin on the surface.
Pseudomonas aeruginosa: virulence factors (lots!)
Neuraminidase: alters receptors to facilitate its own attachment. Elastase: cuts collagen, IgA, IgG, complement, respiratory epithelium, muscle. Alkaline protease: blocks fibrin formation and cuts fibrin. Cytotoxin, hemolysin. Pyocyanin: smells like "sweet grapes," disrupts respiratory epithelium, stimulates inflammation, releases oxygen radicals. Alginate biofilme/mucous: antibiotic resistance, capsule. Pili: bind aialic acid on host.Exoenzymes: impairs phagocytic cells. Exotoxin A (modified protoxin): inactivates EF-Tu in eukaryotes needed for protein synthesis. Endotoxin.
Pseudomonas aeruginosa: transmission, treatment
Soil, water, fomites contact. Gentamicin, carbenicillin and polymixin. Silversulfadiazene (topical) and debridement.
P. aeruginosa: how does it avoid the immune system
It shuts down all it's virulence factors until it reaches a certain population. Then it turns them all on and overwhelms the host system.
Rocky Mountain Spotted Fever: pathogen, what is particular about it? Transmission, incubation period
Rickettsia rickettsi, obligate intracellular, Dermacenter tick: salivary glands bits host (survives infection), takes 6 hours of feeding to transmit normally. 5-10 day incubation.
Rocky Mt. SF: Pathogenesis
Stimulates endocytosis (intracellular), reproduces in phagosome and lyses membrane after reproduction. Buds out of cell like a virus, infects blood vessels, destroys capillaries.
Rocky Mt. SF: signs and symptoms
Sundden fever, headache, chills, vomiting, muscle pain, confusion. Rash: first: spotted non-puritic rash on wrists/ankles -> trunk -> hands and feet. 2nd: petechiae (subcutaneous hemorrhages, not blanchable like first stage)
Rocky Mt. SF: diagnosis, treatment
Serological, clinical, doxycycline (effective within the first week) because of its high concentrations in the skin.
Rocky Mt. SF: complications
30% mortality untreated, 1.4% mortality if treated (in time). Paralysis, hearing loss, secondary Clostridium infection, Gangrene, renal or heart failure.
AIDS: 6 cycles
Binding, reverse transcription, integration, transcription, translation, assembly and maturation
AIDS: Binding process and drug treatment
Virus binds to CD4 receptors (T helper cells) and fuses to the cell. Block with Fuzeon (efuvirtide), which binds to the HIV proteins, preventing attachment
AIDS: reverse transcriptase process and drug treatment
Viral capsule is released and HIV's RNA is made into DNA. Drug: nucleotide reverse transcriptase inhibitor, Retrovir (zidovudine): ontains nucleotide analogs so DNA can't be built.
AIDS: Integration process and drug treatment
Viral DNA is brought into the nucleus and stored with normal DNA. Drug: block with integrase inhibitor, Isentress (raltegravir), which blocks the process of integration
AIDS: Transcription process and drug treatment
Viral DNA is copied into mRNA. Drug: transcription inhibitors
AIDS: Translation process and drug treatment
mRNA is made into proteins. Drug: none given.
AIDS: assembly and maturation process and drug treatment
protease cuts protein chain -> virus is assembled, virus buds off host cell. The virus then must mature. Drugs: block assembly with protease inhibitor Viracept (nelfnavir) that blocks the protease enzyme. Block maturation with Droxia (hydroxyurea)
Typhus: Pathogen, transmission
Rickettsia prowazekii. Transmitted by louse feces, bite wound. War famine, and disaster facilitate. Flying squirrles had fleas in US (rare sylvatic form).
Typhus: incubation, signs/symptoms
High fever (104-105 for 2 wks) Chills, vomiting, malaise, dry cough, myalgia. Photophobia, headache, maculopapular rash.
Typhus: Diagnosis/treatment, complications
Clinical diagnosis. Tetracycline, Chloramphenicol, supportive. 10-60% fatal untreated (age dependent). Myocarditis, CNS disfunction, Brill's disease (reoccurrence 10-40 yrs later b/c it hides in macrophages)
Endemic Typhus: pathogen, transmission, how are symptoms similar/different?
Caused by Rickettsia typhus, transmitted by flea. Milder but similar to Typhus (fever, chills, headache, photophobia, dry cough, mac-pap rash, malaise)
Scrub Typhus: pathogen, area of prevalence, transmission, symptoms, diagnosis, mortality
Orienta tsutsugamushi. Prevalent in the pacific area, Japan, transmitted by chigger. Symptoms: necrotic eschar at bite site, high fever (40 C), fast dissapearing mac-pap rash. Serological diagnosis, 30% fatal if untreated.
Lyme disease: pathogen, virulence, transmission, incubation
Borellia burgdorferi (Gram - spirochete), changes outer surface protein (host can't recognize for long), produces an endotoxin. Transmitted by deer tick typically from NE US. Incubation 7-14 days.
Lyme disease: signs and symptoms of 3 stages
1: bulls eye rash at bite
2: Meningitis, encephalitis, peripheral neropathy, cardiac disfunction.
3: arthritis for years, fever, joint and muscle pain, stiff neck, headache
Lyme disease: diagnosis, treatment
Serological, clinical. Doxycycline, penicillin (long term). Anti-inflammatory drugs can be sued to treat the symptoms of later stages from immune response
Lyme disease: complications, prevention
diagnosis can be difficult (tests are not typically positive early on). Vaccine was withdrawn (orphan drug: <200k people infected in US/yr)
Plague: Pathogen, transmission and incubation for 2 types, pathogenesis
Yersinia pestis, carried by Xenopsylla cheopis flea (dies of infection), Pneumonic is spread person to person. There are sylvatic forms in the SW U.S. 2-7 day incubation for bubonic, 2-3d incubation for pneumonic. Multiplies in LN, ruptures
Plague: Signs, symptoms, and results of two different kinds.
Bubonic: buboes: enlarged, painful LN in groin and armpis, severe headache, fever, muscle pain. Bateremia -> stock, drop in bp, coagulation (DIC), hemorrhaging, tissue death (black death). Death occurs hours to days after bubo develops. 50% fatal w/out treatment.
Pneumonic (5%): fever, severe bloody frothy cough develops w/in hours. 100% fatal if not treated the same day.
Plague: diagnosis and treatment
Clinical, Gram negative bacilli in bubo, blood or sputum. Treat with streptomycin.
Plague: virulence/pathogenesis of pathogen
Switches virulence factors at different temperatures (different in flea and human) Fibrinolysin and phospholipase block throat, flea gets hungry, bites a lot. Once in human, moves to LN and forms bubo. Can spread to blood -> lungs (pneumonic: necrotizing hemorrhagic pneumonia).
Why don't we see plague as much today:
rats are not in our houses, though it is out there.
Smallpox: pathogen, virulence, transmission, incubation
Orhthopoxvirus variola major virus. Adhesions specific to host, proteins that block interferon (key in virus killing) and complement. Transmitted by inhalation of virus crusts. Incubation is 7-17 days.
Smallpox: signs and symptoms
High fever (42 C!), head/muscle aches. Rash that starts in mouth -> face -> body. Start as papules -> vessicles -> pustules. All change at the same time (chicken pox differential)
Smallpox: diagnosis and treatment, prevention, complications
Clinical. Must be grown on eggs to culture. Immediate vaccination can help (virus grows slower than the immune system protects), supportive. Vaccine (cowpox). Complications: high death rate (20%), eradicated, but bioterrorism still an option.
Rubella: pathogen, transmission, incubation, infectious period
Rubivirus: ssRNA enveloped virus. Spread through droplets and fomites. 4-14 day incubation period. Infectious 2 weeks +/- rash.
Rubella: pathogenesis, symptoms,
Errors in DNA replication (ssRNA). Severe in adults. Enters URT -> blood -> lymph, -> body. Pink macules, 3 day duration (spreads from face to trunk)
Rubella: diagnosis and treatment, complications
Clinical, serological. Prevented by the MMR vaccine. Congenital rubella Syndrome: birth defects: microcephaly (small head), deafness, blindness, mental retardation, death. In adults: arthritis, encephalitis.
Fifth disease: Pathogen transmission, incubation, pathogenesis
Parvovirus B19: Highly infectious, spread by respiratory drops. Incubation period of 4-12 days. Replicates in RBC precursors -> damages erythrocyte development.
Fifth disease: symptoms
Fever, malaise, headache, myalgia. Face rash (slapped fach) moves to exposed arms/legs (macular/lace-like). Stays for 1-2 weeks (Rubella differential). Sun exacerbates rash.
Fifth disease: diagnosis and treatment, complications
clinical, serological. No treatment - supportive. C: fatal anemia in patients with blood diseases such as sickle cell anemia (damages RBC development). Placental transmission in 1st 20 weeks may cause miscarriage.
Chicken Pox: pathogen, transmission, incubation, pathogenesis, infectious period. transmission rate
varicella-zoster virus (herpes virus. Spread by respiratory or vesicle (skin break). 14-28 day incubation period. URT -> lymphatic -> skin and nerves (shingles). Infectious 1-2d before rash and during symptoms. 75%
Chicken Pox: symptoms
fever, malaise. Rash: macules -> papules -> vesicles -> crust, change at different times. Starts at back of neck/ears -> trunk -> arms. Sequelae: shingles (15-20%): painful banded rash.
Chicken Pox: diagnosis and treatment, complications
clinical, serological. Vaccine, supportive. Shingles, secondary infections, Reyes syndrome, organ dissemination, pneumonia
Measles: Pathogen, signs and symptoms, treatment
fever, dry cough, coryza, conjunctivitis, erythematous, maculopapular rash (face to trunk), koplic spots. Prevent with MMR vaccine
Herpes simplex virus 1: signs/symptoms, treatment
Sores in mouth (cold sores), or infection of the eye. Blisters/ulcers around mouth, lips, gums. Enlarged lymph nodes in neck/groin, fever (probably on in first infection). Most infections are mild, so no treatment is used. Prolonged outbreak of immunodeficiency: acyclovir, famcyclovir, valacyclovir.
Ringworm: Pathogen, signs and symptoms, treatment
Tinea species (capitis, barbae, corporis, pedis) all are dermotophytes (a fungus NOT a worm). Causes itching, ring-shaped rash (red colored); border of rash lesions look scaly, may blister or ooze. Wash clothes and linens daily, clean area, miconazole, clotrimazole if needed.
Cholera: pathogen, virulence
Vibrio cholerae: Gram - curved rod. Cholera toxin (AB toxin) B binds to upper tintestinal epithelial cell receptors, releases A into the cytoplasm where it uses adenylatecyclase to cativate cAMP that opens ion channels -> water efflux (water follows salt). (video in class)
Cholera: ID in water/food) transmission, incubation
Water: ID = 10^3-6. Food: ID = 10 ^2-3. Fecal-oral (food or water, undercooked seafood). Survives in salt/fresh water, but not infectious in salt (biofilm). Incubation: 1-2 days
Cholera: signs and symptoms:
rice-water, odorless diarrhea, no WMCs in stool. Dehydration, tachycardia, sunken features, wrinkled skin, muscle cramps (all from water and electrolyte loss)
Cholera: diagnosis and treatment, complications
Clinical, Gram - curved rod in stool. Oral or IV rehydration is needed. Docycycline reduces toxin output. Do not use antacids - increases severity. Kidney failure, coma, 50% mortality untreated.
Enterohemorrhagic Escherichia coli: pathogen, virulence
E. coli 0157:H7. Shiga-like toxin: inhibits protein synthesis, cytotoxic. Type III secretion: injects receptor for own uptake -> displaces normal flora.
E. coli 0157:h7: transmission, ID
Transmission: fecal-oral (food ). 50% of cow carcasses, unpasteurized juices, raw hamburger. Low ID: 10-100
E. coli 0157:H7: pathogenesis, symptoms
Destroys microvilli on intestine. Shiga toxin: bloody diarrhea, kidney damage. Attaches to neutrophils -> dissemination. Bloody diarrhea, reduced urine output. Hemolytic uremic syndrome: RBC lysis, low platelet count, kidney failure -> 5-15% mortality in US
E. coli 0157:H7: Diagnosis and treatment, complications
Bacteria in stool, no sorbitol fermentation. Antibiotics and antidiarrheals may enhance HUS (shiga) toxin. Supportive, dialysis, hemadialysis. C: kidney failure.
Campylobacteriosis: pathogen, transmission, incubation, duration, ID. Toxin
Campylobater jejui. Raw meat, unpasturized milk, pets, STD. 100% birds harbor. 1-7 day incubation, 3-7day duration (up to 2wks). ID: 10k cells. Cholera-like enterotoxin.
Campylobacteriosis: signs and symptoms
Fever, headache, myalgia -> severe abdominal pain -> bloody watery diarrhea (>10/day)
Campylobacteriosis: diagnosis and treatment
Bacteria in stool on selective medium. Typically self-limiting (no treatment). Erythromycin MAY shorten course if given EARLY.
Guillaine-Barre syndrome: autoimmune attack on nerves -> paralysis. Surface antegins are similar to host myelin -> rheumatic fever. Hemolytic uremic syndrome (RBC lysis, low platelet count, kidney failure).
Salmonellosis: pathogen, virulence,
Salmonella enterica. Salmonella toxin: similar to cholerae
Salmonellosis: ID, pathogenesis, transmission, incubation period
ID: 10^3. Acid resistant (survives stomach acid), attaches to intestinal cells, induces uptake, kills cells. Incubation:4-48 HOURS. From contaminated foods, reptiles, unpasteurized dairy, veggies, undercooked meat.
Samonellosis: symptoms, length of infection
Nausea, vomiting, headache. Diarrhea (rarely blood) and cramps 3-7 DAYS. Gastroenteritis infection (bacteria are GROWING in intestine, releasing toxin).
Salmonellosis: diagnosis, treatment, complications
clinical; salmonella in stool. Self-limiting, supportive. Antacids and beta blockers increase incidence (b/c they reduce stomach acid). C: Reiters syndrome: arthritis in rare cases; 5% bacteremia
S. aureus food poisoning: virulence
Survives high salt, enterotoxins are heat stable: the bacteria dies but the toxin doesn't (INTOXICATION)
S. aureus food poisoning: signs/symptoms
nausea, projectile vomiting, diarrhea, cramps
S. aureus food poisoning: transmission, incubation duration
Contaminated foods from wound or skin. 4-6 hour duration, 24 hour duration.
S. aureus food poisoning: diagnosis and treatment
clinical, culture food, vomit or stool. Self-limiting, fluid replacement.
Fungal meningitis: pathogen, transmission, pathogenesis. Incubation period
Cryptococcus gattii, capsule. Spore inhalation from tree bark and debris (typically from tropics, transported to NW by trucks). Enters lungs -> CNS. Cryptococcal neoformans is most common, but only in IC people. Incubation: 2-14 months. Not contagious.
Fungal meningitis: signs and symptoms of
Typically asymptomatic. Pulmonary: cough (wks), sharp chest pain, severe headache, fever, night sweats, weight loss.
Meningitis: symptoms develop over months. Headache, drowsiness, dizziness, irritability, confusion, nausea, vomiting, stiff neck, ataxia, coma. Lesions may develop (bone, skin, etc.)
Fungal meningitis: treatment, complications
Amphotericin B (6wks) -> fluconazole (10wks). AIDS patients require lifelong therapy. C: CNS infection and organ involvement
Bacterial Meningitis: classic pathogen, virulence factors, where does it live in the body?
Neisseria meningitidis (Gram - dipplococci), fimbirae, capsule, endotoxin (needs ALL three to be virulent). Can live in macrophages and neutrophils.
Bacterial Meningitis: N. m.: incubation period, signs and symptoms. When does death occur?
3-4 day incubation. Sudden high fever, severe headache, STIFF NECK, vomiting, confusion, irritability, fear. Petechiae, blanching rash (trunk, legs, mucous membranes), DIC. Death occurs within 6 hours of initial symptoms.
Bacterial Meningitis: N. m.: transmission
respiratory -> lung, ear, sinus -> meninges of the brain. Most common along wwith S. penumonia, epidemics amng college and military groups (15X more than normal)
Bacterial Meningitis: N. m.: Diagnosis and treatment. Prevention
Clinical, spinal tap shows leukocytes. Penicillin, bacteria spread 24 hours after treatment. C: 100% fatal if not treated, 10% if treated. Encephalitis (brain): deafness, blindness, coma, death. Vaccine
Moroxella caarrhalis: morphology, symptoms
Gm- diploccocci. Otitis media, sinustitis, pneumonia, meningitis is RARE.
Bacterial meningitis: most common pathogen, virulence
Streptococcus pneumoniae Gm +, Secretory IgA protease: destroys.
Pneumolysin: pore-forming toxin damages lysosome/blocks complement.
Phosphorylcholine: binds host cells, simulates uptake.
Bacterial meningitis: Streptococcus pneumoniae: virulence
Capsule, secretory IgA protease: cuts the antibodies of mucous membranes.
Pneumolysin: pore-forming toxin damages lysosome/blocks complement
Phosphorylcholine: binds to cells and stimulates uptake.
Bacterial meningitis: streptococcus pneumoniae: pathogenesis and transmission
Gm +, grosses meninges via cellular uptake. Part of the normal flora in 5-10% of adults, in 20-40% of kids.
Normal throat flora -> lungs -> meninges. Leading cause of pneumonia in adults.
Bacterial meningitis: S. pneumoniae: signs/symptoms, diagnosis, treatment, mortality rate?
High fever, severe headache, vomiting, confusion, irritability, fear.
Clinical diagnosis, spinal tap shows WBCs.
Treat with Penicillin, 35% mortality.
Haemophius influenzae: morphology, cause of what?
Gm - pleomorphic, most common cause of childhood meningitis prior to vaccine (Hib).
Bacterial meningitis: S. agalactiae: virulence factors, transmission. How many people hold it
Capsule (it has a LAC of virulence factors).
Part of the normal vaginal tract -> newborn -> respiratory tract -> meninges. 30% of women are carriers, 5-40% transmission, 1-2% clinical disease.
Causes mastitis in cows (transmitted in unpasteurized.
Bacterial meningitis: S. agalactiae: signs/symptoms, diagnosis, treatment, complicaiton
sudden high fever, severe headache, vomiting, confusion, irritability, fear, capsule.
Diagnosis: test mother at week 38 for group B strep. Clinical, spinal tap, penicillin.
C: 25% survive with permanent neurological damage: blindness, deafness
Bacterial meningitis: Listeriosis: pathogen, virulence
Listeria monocytogenes. Listeriolysin O: hemolysin digests phagosome: prevents phagosome/lysosome fusion (pH-regulated, so turns off when outside, on when inside)
actin mobilization, grows at 4 degrees C, InIA/B: triggers endocytosis.
Bacterial meningitis: Listeriosis: pathogenesis, transmission, ID & incubation
Contaminated food items carry bacteria.
Intestine, liver/spleen, brain/placenta. InIA/B binds to human E-cadherin cell adhesion proteins for entry and cell-to-cell transfer. Low ID and 1 week incubation
Bacterial meningitis: Listeriosis: signs and symptoms
Adults: fever, myalgia, nausea, vomiting diarrhea.
Causes meningitis in pregnant women, babies, and immunocompromised.
Viral meningitis: pathogen, virulence
Picornavividae enterovirus (coxsackie A and B, echovirus. Non enveloped, ssRNA virus
Viral meningitis: transmission, incubation and duration. Chance of infection, period one is infectious
Fecal-oral transmission. Survives in chlorinated pools. 3-7d incubation, 7-10d duration. 1:100 chance of getting meningitis. Infectious for time of symptoms + 10days.
Viral meningitis: diagnosis and treatment
Clinical, no bacteria in CSF. Supportive care should be given. complications are rare - milder than bacterial meningitis
Bacterial meningitis: Listeriosis: treatment, complications (death rate too)
Ampicilin and gentamicin. 20-30% death rate. Miscarriage, still birth, premature birth
Viral meningitis: signs and symptoms
Fever, severe headache, stiff neck, vomiting, confusion, irritability, milder than bacteria.
West Nile Virus: pathogen, virulence
West nile virus, non enveloped ssRNA.
West Nile Virus: transmission, incubation, pathogenesis, incubation
mosquito bite eggs -> blood -> brain. Incubation: 3-14 days.
Viral meningitis: Listeriosis: morphology and treatment
Gm + coccobacillus
West Nile Virus: signs and symptoms of different stages
Flu-like: mild cold symptoms, 80% no symptoms
Encephalitis: abrupt headache, high fever, stiff neck nausea, vomiting, DISORIENTATION, COMA, CONVULSIONS, PARALYSIS. Skin rash in some (trunk).
How to tell viral meningitis and West Nile apart.
History (mosquito bites), West Nile shows nausea, coma, convulsions, paralysis, disorientation and skin rash in some. Identify WN with serological tests.
West Nile Virus: diagnosis and treatment
Clinical, serological. Prevent with repellent. Treatment is supportive. There is a vaccine for animals but not approved for humans
Leprosy: pathogen, virulence
Mycolic acid: waxy layer/coating that resists lysis, growth in phagocytes
Leprosy: transmission, pathogenesis
Spread person to person (need long-term contact). Aerosolization, cuts, fomites. Slow growth , years to presentation. Grows best at low temp: hands, feet nose, lips), targets peripherial nerve endings. CMI (cell mediated immune response) tissue destruction leads to symptoms
Leprosy: signs and symptoms of two for types - why two types
Two different cell-mediated responses lead to the tuberculoid form and the lepromatous form.
Tuberculoid: strong CMI response: nerve damage.
Lepromatous: weak CMI: disfigurement, hypopigmented lesions, numbness, weakenss.
Leprosy: diagnosis and treatment, complications
D: clinical, acid fast rods. A lepromin test may be negative in late stage.
T: Rifampin and sulfone combination for a long time.
Vaccine: BCG attenuated M. bovis is only 26% effective
C: secondary infection
Botulism: pathogen, morphology, requirements, virulence
Clostridium botulinum, Gram +, obligate anaerobe. Botulism toxins A-G: neurotoxins.
Acid stable, heat labile (80 C for 20 min)
VERY potent : 30g would kill all of US
Botulism: transmission, pathogenesis, incubation period
Food: canned (pH >4.5), honey (infants) Very low dose (liking a spoon) causes death.
Central endospore swallowed, grows in intestine -> toxemia.
Incubation: 1-4 days (food-wound)
Botulism: signs and symptoms in adults and infants
abdominal pain, dry mouth, nausea, dysphagia (difficulty swallowing), vomiting, diarrhea, dyspnea, ptosis (drooping of eyelid), descending paralysis.
Infant: lethargic, weak cry, doesn't eat (ptosis), floppy baby syndrome, constipation. SIDS connection?
Botulism: diagnosis and treatment, complications
Clinical, mouse test (give food samples to mouse...)
T: antitoxin (from horse), flush intestine, supportive. Antibiotics may WORSEN infant botulism (releases toxin all at once).
C: secondary infectious. Pneumoniae
How does the botulism toxin work?
It blocks acetylcholine release, leading to paralysis.
Tetanus: pathogen, morphology, virulence
Clostridium tetani. Gram + anaerobe. Tetanospasmin neurotoxin: release upon cell death - prevents GABA and lysine release (inhibitory neurotransmitter). In spinal cord - nonreversible. Terminal endospore leads to toxemia.
Tetanus: transmission, mortality
Wound contamination: splinters, nails, cuts, drug use.
Endospores found in soil and animal feces.
1 million cases a year (1/2) are neonatal).
50% mortality in adults, 90% neonatal
Tetanus: incubation, signs and symptoms
Incubation period: 3 days to 15 wks. Stiff neck and jaw muscles, drooling, sweating, back spasms, anger, irregular heartbeat, fluctuating blood pressure.
Tetanus: Diagnosis and treatment, how does death occur
D: clinical identification is typically too late.
T: Metronidazole (NOT penicillin, may increase contractions)
Antitoxin intrathecally (into CNS), wound debridement
Vaccination: tetanus toxoid. Booster needed every ten years
Death results from irreversible contraction of diaphragm
Differentials for tetanus
How does tetanospasmin work?
toxin blocks release of neurotransmitters, can't relax
Poliomyelitis: pathogen, virulence
Picornaviridae EnteroPoliovirus. Replication in neurons, cytolysis of cells
Poliomyelitis: transmission, level of infectiousness, host, pathogenesis
Fecal-oral, stable in pools and lakes for long periods.
Secreted in feces for weeks. Nearly 100% infectious, human host only.
Throat/intestine -> LN/blood -> upper spinal cord neurons/brain stem.
Poliomyelitis: Symptoms of three "types"
Most people are asymptomatic (90%).
Minor: fever, headache, sore throat (5%)
Non-paralytic aseptic meningitis: fever, headache, sore throat, muscle spasms, back pain (2%)
Paralytic: fever, myalgia, flaccid paralysis (<1 %). Bulbar infects brain stem -> breathing difficulties.
Poliomyelitis: Diagnosis and treatment, complications
clinical, virus IN CNS.
C: post polio syndrome 30-40 yrs post-disease in 30-50% of people (usually milder)
Polio types of vaccines and benefits
IPV Salk and OPV (live attenuated, shed in feces for 6 weeks)
Rabies: pathogen, type, virulence
Rhabdoviridae Lyssavirus Rabies virus (-RNA).
Glycoproteins mediate attachment -> endocytosis into skeletal muscles.
Endemic in animals, saliva transmission, 55k deaths/yr 10m post exposure vaccination. majority of victims are <15 yrs
Rabies: pathogenesis, incubation, symptoms
Bite wound (rarely aerosolization) -> skeletal muscles -> neuromuscular junctions -> neurons -> CNS -> saliva).
Incubation: 20-90 days.
Symptoms: pain/itching at wound site, fever, headache anorexia. Hydrophobia (don't drink water), seizures, disorientation, hallucinations, paralysis, respiratory paralysis, encephalitis. Can have either furious or dumb type.
Why did we see a spike in polio when water treatment got so good?
don't develop immunity from mother's antibodies anymore because mother is no longer infected. Kids would then get community infections
Rabies: diagnosis for humans and animals, treatment, mortality
PCR (genetic) test from saliva, Ab in spinal fluid, Ag in biopsy of nerves at base of neck and hair follicles.
Animal: direct fluorescent of Ab (finds antigen), negri bodies in brain
T: wash with soap and water quickly, apply ethanol. Treat post exposure with prophylaxis HDCV.
100% fatal if not treated
Animals have oral vaccine available
Valley fever: pathogen, virulence
Coccidiodes immitis, resistance to immune response, VERY resistant to antifungals
Valley fever: transmission, pathogenesis, incubation
Common fungal infection, endemic in SW U.S.Inhale fungal spores ID = 10. (Arthroconidia). disseminates to lungs and other tissues
Valley Fever: Signs and symptoms
60% asymptomatic. Fever, cough, headache, myalgia, NIGHT SWEATS, JOINT POINT, RASH. Dissemination leads to meningitis.
Valley Fever: diagnosis, treatment, complications
prescence of spores in tissue sample (rash), skin test, chest xray, serology.
Treatment: fluconazole, amphotericin B (long-term)
C: chronic form my recur years after initial infection
Strep throat: pathogen, virulence factors
Streptococcus pyogenes. M protein: destabalizes complement to block opsonization.
Hyaluronic acid (looks like host prevents attack)
Streptokinase: dissolves clots
Streptolysin: pore-forming cytotoxin
C5a peptidase prevents complement recruitment of WBCs.
Pyrogenic toxins: stimulate cytokine releasein WBCs -> fever, rash, shock
Strep throat: transmission incubation, time on is infectious
coughing. Incubation 3-5 days. Infectious period: 2 days post antibiotics
Strep throat: Signs and symptoms
fever, malaise, headache, red painful pharynx (throat), swollen LNs, abscesses on tonsils.
Strep throat: diagnosis and treatment,
Clinical, streap test is needed for group A, Beta-hemolytic.
T: penicillin/amoxicillin (clindamycin)
Strep throat: complications
Scharlet fever: erythrogenic toxin: occurs 2 days after sore throat: strawerry tongue, rash (neck, body, skin sloughs off after 1 week.
Rhematic fever: autoimmune vs. heart valve: heart failure (looks like heart muscle)
Necrotizing fasciitis, acute glomerulonephritis: IgG Ab Ag complex in kidneys
Diptheria: pathogen, morphology, virulence
Coryebacterium diptheriae (Gm + pleomorphic), A-B toxin: carried by lysogenic phage, A binds, B cleaves once inside. B destroys elongation factor -> blocks protein synthesis -> cell death.
Diptheria: transmission, host?
Normal flora of many systems of animals and humans. Aerosolization or contact. Human host only. Leading cause of childhood death pre-vaccine (4 BC). "Strangling angel of children."
Diptheria: signs and symptoms
Grandual onset sore throat, fever, difficulty swallowing. Discharge (bacteria ,WBCs, dead cells). Pseudomembrane (thing in throat)
Diptheria: diagnosis, treatment, prevention, complications
Clinical, Gm+ pleomorphic. Elek test: Ab to toxin used to detect.
T: antitoxin, penicillin or erythromycin. Tracheostomy.
Prevention: Dtap vaccine.
C: suffocation (10-20%), kidney damage, myocarditis
Bacterial pneumoniae: pathogen, morphology, virulence factors
Streptococcus pneumoniae, gram + diplococci. CbpA adhesion that binds to pulmonary epithelium and nasopharynx, DspA inhibits opsonization
Bacterial pneumonia: S. pneumoniae: transmission, pathogenesis. At risk groups?
Normal flora in 75% of population. Throat, inside aveolar cells, cells leak plasma WBCs to lung -> congestion and inflammation. Smokers and alcoholics more at rish. Aslo those with flu, IC
Bacterial pneumonia: signs and symptoms
fever, dry cough with blood, congestion, chest pain, rapid short breathing (aveolar cells are filled)
Bacterial pneumonia: diagnosis, treatment, prevention, complications
clinical; gram + dipplococci and polymorphonucleocytes (PMNs) in sputum. Serological testing
T: penicillin, vancomycin.
Vaccine (23 serotypes)
C: can cause invasive form, meningitis, associated with influenza co-infection.
Primary atypical pneumonia: pathogen, morphology, virulence
Mycoplasma pneumoniae (Gram + pleomorphic, stains GM - ) capsule, hydrogen peroxide production (damages cells). Adhesin binds to URT epithelium
Prymary atypical pneumonia: transmission, pathogenesis
normal flora, most common cause of pneumonia in college students. Aerosolization.
Throat -> ciliated cells, stops cilia, cell death.
Primary atypical pneumonia: signs and symptoms
fever, headache, sweating, sore throat, UNPRODUCTIVE cough, symptoms up to one month
Primary atypical pneumonia: diagnosis, treatment, complications, differentials
Clinical, small pleomorphic that stains Gm -, slow growth in culture.
T: erythromycin or tetracycline, patients are infectious for a long time.
C: meningitis: Differential: viral pneumonia (viral includes a stiff neck ,vomiting, confusion, irritability)
Pertussis: pathogen, virulence factors
Bordetella pertussis. Gm- coccobacillus.
Filamentous hemagglutinin (binds to cells)
Pertussis toxin: adhesion and toxin -> mucous
Adenylate cyclase toxin: inhibits leukocytes
Dermonecrotic toxin: vasocontrictor -> cell death
Tracheal cytotoxin: inhibits cilia; cytotoxic
Pertussis: transmission, pathogenesis, incubation
aerosolization, highly infectious especially in those <5 years old. NO animal or environmental reservoir. Binds to ciliated epithelium, stops movement, kills cells. Symptoms occur post clearance of the organism (damage already done). Incubation period 7-10 days for catarrhal form.
Pertussis: signs and symptoms for two forms
Catarrhal: mild runny nose, cough fever.
Paroxysmal (2-4wk duration): 1-2 wks after catarrhal: severe coughing, choking, vomiting, exaustion, ruptured vessels in eyes.
Pertussis: diagnosis and treatment, prevention, complications
clinical (mild in adults). Sputum: Gm- coccobacillus.
T: supportive car (because symptoms occur post clearance, you can't kill the organism) ezythromycin prior to cough.
Prevention: DTap vaccine
Tuberculosis: pathogen, virulence
Mycobacterium tuberculosis. Mycolic acid: waxy coat prevents drying, lysis, destruction by macs. Cord factor: keeps cells attached, inhibits neutrophil import, kills host cells.
tuberculosis: transmission, ID pathogenesis
Coughing (aerosolization), rods can remain viable for up to 8 months dry. #1 HIV killer. ID: 10 (10-30% transmission). Droplet, to lung, mac, tubercle (lungs tries to wall off bacteria)
Tubercle: macs and collagen ball in lungs
Stalemate: either host kills bact. or bact. escapes. Can be reactivated and cause secondary infection. Can disseminate and spread to other organs via macs.
TB: signs and symptoms, complications
Mild fever, productive cough, difficulty breathing, chest pain, wheezing, cough up blood, night sweats.
Complications: drug resistance; 50% death untreated
TB: diagnosis, treatment, prevention
Acid fast rods in sputum, skin test (must confirm with chest x-ray).
T: Isoniazid, rifampin, pyrazinamide, and ethambutol (2 months and 4 months). DOTS-plus program directly observes patients taking treatment. There is an attenuated M. bovis vaccine, but it is only 50% effective, takes a long time to grow, and our skin test would then show positive.
Respiratory syncytial virus: s/s, treatment
bluish color of skin, dyspnea, "seal bark" cough, fever, runny/stuffy nose. Supportive (breathing machine, IV fluids if severe)
Gonorrhea: pathogen, morphology, virulence
Neisseria gonorrhoeae. Gram + diploccocci. Fimbriae, Capsule, endotoxin, IgA protease.
Gonorrhea: transmission, pathogenesis, ID
STD, ID = 100. Common in urban poor. Pili attach to mucous membranes, survive neutrophils. Can attach to sperm and move up the fallopian tubes. Women are much more likely to acquire than men.
Gonorrhea: signs/symptoms in male/female
Male: urethritis, dysuria, discharge
Female: 50-80% asymptomatic; discharge
Gonorrhea: diagnosis, treatment
Clinical, Gm + diplococci in discharge. Co-infections w/ Chlamydia are common.
T: Cephtriaxone IM SINGLE DOSE.
Prevent with condom use, there is no long term immunity (multi strain)
infertility as infection progresses (epididymis, fallopian tubes): PID (pelvic inflamm.), ectopic pregnancies.
Proctitis (inflammation of rectum and anus), pharyngitis (disseminated infectious (<1%)
Neonatal eye infectious -> blindness (can treat with drops)
Chlamydia: pathogen, requirements, cell wall? virulence
Chlamydia trachomatis (15 immunotypes, obligate intracellular, no peptidoglycan.
Chlamydia: transmission, incubation, pathogenesis
Most common bacterial STD. Microlesions in mucous membrane (1-3 week incubation) -> cytolysis, dissemination, inflammation.
Trachoma: droplet, fomites, hands, flies, birth.
Chlamydaia: signs and symptoms of two kinds
W: 85% asymptomatic; discharge.
M: 50% asymptomatic; discharge, dysurea, urethritis.
Trachoma: lid scarring (turns lids inward) -> corneal scarring, angiogenesis (forming of blood vessels) -> blindness. (#1 cause of infectious blindness)
Lymphadenitis: localized pain, lymphadentidis, bubo ruptures
Chlamydia: diagnosis/treatment, complications
Vaginal urethral swabs -> intracellular org. -> cell culture and FA testing (fluorescent Ab)
T: azithromycin/erythromycin. Trachoma has a surgical correlation
P: condoms (not too effective - sterile)
Human papilloma virus: pathogen, virulence
more than 100 types; 40 mucosal STD. DNA virus: inserts into host genome
Human papilloma virus: transmission, clearance, risk factors, increases chance of what?
most common STD, 50% of sexually active ppl acquire it (50% of those are 15-24).
Any type of sexual intercourse can transmit.
90% of infections self-clear in 2 years
Risk: smokers, IC, increased risk of herpes infection and cervical cancer.
HPV: signs and symptoms, incubation, duration
visual or subclinical anogenital warts. Itching, pain, increased discharge, cervical cancer is associated with type 16/18 (causes 70%). 3-4 month incubation, 1-2 year duration
HPV: diagnosis and treatment, complications
Pap smear detects early cervical cancer.
T: do not use OTC wart removal. Condoms do NOT help prevent spread. Gardasil Vaccine does, but is expensive.
C: cervical cancer/anal, vaginal/penile cancer
Epididymitis, orchitis (inflamm of testicles, proctitis, pharyngitis, PID, cervical cancer, neonatal pneumonia.
Reiters syndrome: eye redness, arthritis, urethritis, HLA-B27
LGV (lymphogranuloma venereum): genital sores, genital elephantiasis, arthritis.
A leading cause of female infertility.