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SM Flashcards

1
Q

Resist: VRE

A

• VRE (vancomycin resistant enterococcus): mutates terminus to D-ala-D-lactate, Vancomycin normally binds to D-alanyl-D-alanine terminus and blocks linkage to glycopeptide polymers
Vanco: only effective vs gram+

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2
Q

• Coronavirus:

A

• Coronavirus: ssRNA+, encapsulated, replicates in cytoplasm
• Unique: helical virus, SARS, common cold, MERS
○ Acute bronchitis –> acute respiratory distress syndrome
Test via PCR or antibody detection

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3
Q

Resist: MRSA

A

MRSA (methicillin-resistant staph aureus): mutates PBP to PBP2a, now penicillin cannot bind so cross-linking of peptidoglycan continues as normal

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4
Q

MIC interpretation

A

• MIC interpretation: minimum inhibitory concentration (MIC)
• Lowest concentraiton of an antibiotic that prevents visible growth of bacteria after 18-24 hours of incubation
○ Expressed as concentration mg/ML
○ Breakpoint: seperates strains where this is a high likelihood of treatment success vs. those that will likely vail treatment
§ Want to use the drug that is furthest from the breakpoint!
• Serial tube dilution
• Automated microbrowth dilutions or premade cassettes/cards

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5
Q

• Bacillus anthracis

A

• Bacillus anthracis
• Gram + bacillus, “rods in chains”, poly-D-glutamate protein capsule, obligate AEROBE
• Transmission: spores–> inhalation, cutaneous
• Disease:
○ Cutaneous: black eschar with cutaneous inflamed ring
○ Pulmonary anthrax: wool sorters disease, starts with non-specific cough symptoms, can progress to pulmonary hemorrhage (100% mortality), chest x-ray shows widened mediastinum (lymph nodes)
• Virulence/toxins:
○ Edema Factor: acts like adenylate cyclase, increases cAMP, increase edema
○ Lethal Factor: exotoxin, protease that cleaves MAP-kinase, results in tissue necrosis
Tx: Fluoroquinolones, Doxycycline

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6
Q

HPV

A

• HPV: dsDNA, naked
• Strains 1-4: verruca vulgaris (cutaneous common wart)
• Strains 6, 11: Laryngeal papillomatosis (recurrent respiratory papillomatosis),
○ Acquired during vaginal birth
• Strains 6, 11: condyloma cuminata (anogenital warts)
○ Acquired during sex
• Strains 16, 18, 31, 33: anogenital cancers, squamous cell carcinoma
○ Acquired during sex
• HPV vaccine: 6, 11, 16, 18, guardasil
○ Most common STD
• Cancer mechanism: HPV encodes E6 (proteolysis of p53) and E7 (RB targeted)
○ AIDS-defining illnesses: immunosupression increases risk of HPV cancers
○ Post-coital bleeding, think CANCER
Pap smear: screening for cervical cancer (Koilocytes, bi-nucleated risky)

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7
Q

ID of step. spp.

A

Identification of streptococci: grows in strips, patterns of hemolysis differentiate
• Parital lysis, green, Alpha: viridans, pneumoniae
• Total lysis, glow, Beta: pyogenes, agalactiae
No lysis, Gamma: gallolyticus

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8
Q

• Mucormycossis

A

• Mucormycossis
○ R: mucor and rhizopus both cause, opportunistic infections (leukemia, neutropenia, diabetes)
§ Bread mold
§ Transmission: inhalation of spores
○ C: diabetic keto acidosis: most common clinical predisposition
§ Proliferate in blood vessels -> Penetrates the Cribiform plate -> enter brain -> necrotic tissue around eyes and nose “rhinocerebral mucormycoses”
H: Wide-angle branching (90 degress), nonseptate rods

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9
Q

• Malaria

A

• Malaria
○ Transmission of Plasmodium by Anopheles mosquito
○ Clinical manifestation:
§ Falciparum: edothelial cyto-adherence result in capillary bed occlusion –> end organ dysfucntiono
§ Cytokine release: TNF, IFN, IL1, diffuse endothelial activation/inflammation, capillary leak syndrome
§ Anemia
○ Testing: thin-film, thick-film blood smear
§ Rapid test: antigen testing
PCR: send out test, confirms species

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10
Q

CMV

A

• CMV: cytomegalovirus, DNA virus, herpes virus family
• Transmission: blood, sex, breast milk, saliva, TORCH
○ Congenital CMV: blueberry muffin rash (petechial rash), hepatosplenomegaly, jaundice, sensorineural deafness, peri-ventricular cranial calcify, ventriculomegaly–> seizures, 85% asymptomatic ; 2nd trimester maternal transmission
§ #1 congenital fetal viral infection: #1 cause sensorineural hearing loss
§ Hydrops fetalis: loss of fetus
○ CMV pneumonia: especially in transplant patients
○ CMV retinitis (pizza pie retinopathy), CMV esophagitis (linear ulcerations), CMV colitis (with ulcerated walls)
§ CD4 count <50
○ CMV mononucleosis: in non-suppressed people, mono-spot test would be negative
• Latency: mononuclear cells (B T macrophages), owl’s eye inclusion bodies in infected cells
• Reactivation: under immunosuppression
• Tx: gancyclovir, phoscarnet (for UL97 gene mutation)

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11
Q

• Streptococcus pyogenes

A

• Streptococcus pyogenes
• Gram + cocci, GAS, bacitracin-sensitive, encapsulated (hyaluronic acid, non-immunogenic), beta-hemolytic
• Diseases:
○ Pharyngitis: strep throat
○ Impetigo: skin, honey-crusted
○ Cellulitis:
○ Erysipelas: well demarcated borders, #1 cause
• Autoimmune mediated disease:
○ Rheumatic Fever: only happens post pharyngitis, auto-immune response to mimicry of M-antigen, resulting in attack of heart tissue/mitral valves, type 2 hypersensitivity rxn
§ Joints polyarthritis, Heart valvular damage, myocarditis, endocarditis, Nodules, Erythema marginatum, Sydenhams Chorea
§ Prevented by penicillin treatment of primary infeection
○ Post-strep glomerular nephritis: coke-colored urine, facial edema, 2 weeks can after pharyngitis or superficial/impetigo, type 3 hypersensitivity rxn (immune complexes deposit into glomerulus)
§ Not prevented by penicillin of primary infection
• Toxin mediated disease:
○ Scarlet Fever: strawberry tongue, pharyngitis, wide-spread rash that spares face
○ Necrotizing fasciitis: invade fascia, spreads rapidly
○ Toxin shock-like syndrome: superantigen
• Toxins
○ SpeA: superantigen TS/SF; SpeB: protease nec. Fasc.; SpeC: super antigen TS/SF
• Virulence:
○ M-protein: interferes with opsonization, antigenic/mimicry in RF
○ Streptolysin O: we generate antibodies to this
○ DNAse
○ Streptokinase: converts plasminogen to plasmin (given to break up clots in people)
• Tx: Penicillin
• Testing: Blood test for Anti-streptolysin O

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12
Q

• Pneumocystosis

A

• Pneumocystosis
○ R:
§ Transmission: respiratory transmission
○ C: Pneumocystis Pneumonia (PCP), healthy and immunocompromised can be infected but compromised only show symptoms
§ AIDS defining illness: CD4 count under 200 (start prophylaxis at this level)
§ X ray: whispy diffuse infiltrate, ground glass appearance (crushed ping pong balls)
H: bronchoaveolar lavage, lung biopsy, methamine silver stain will show disc shaped yeasts

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13
Q

• Lincosamides:

A

• Lincosamides: binds 50S ribosomal subunit–>stops peptide synthesis/protein formation
○ Bacterialstatic
Similar mech to: Macrolides, Clindamycin, Erythromycin, Linezolid, Chloramphenicol

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14
Q

Staphylococcus aureus

A

• Gram + cocci, grows in clusters, coagulase +, catalase +, grows golden on blood agar, beta-hemolytic, ferments mannitol (turns mannitol-salt agar yellow)
• Diseases: colonizes nose
○ Inflammatory:
§ Pneumonia: patchy infiltrate, post-viral secondary superinfection
§ #1 adults Septic arthritis
§ Cellulitis/Impetigo/Carbuncles/Furuncles: erythematous abscess
§ Rapid onset Endocarditis: tricuspid infection (IVDU)
§ #1 osteomyelitis
○ Toxin mediated:
§ Food poisoning: mostly emetic, fast onset, pre-formed toxin, 1-8 hours, meats/creams
§ Scalded skin syndrome: exfoliative toxin, skin peals off
§ Toxic shock syndrome: TSST superantigen, overactivation of T cells cytokine storm, forms in wound packing/tampons
• Virulence:
○ Protein A: component of cell wall, binds FC portion of IgG, prevents opsonization/complement activation
○ TSST-1: mediates toxic shock syndrome, super antigen
○ Exfoliative toxin: mediates scalded skin syndrome
Tx: Naficillin (if methacillin sensative), vancomycin (if MRSA, mutates PBP)

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15
Q

• Actinomyces

A

• Actinomyces
• Gram + , branched/filamentous rod, OBLIGATE ANAEROBE
• Transmission: normal flora of oral cavity–> jaw trauma/procedures can cause it to spread into wound
• Disease: cervicofacial actinomyces infection
○ Slow course, forms lump then abscess then sinus tracts draining sulfur granules
• Unique: sulfur granules (yellow), sinus tracts
Tx: penicillin G, surgical drainage

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16
Q

• Nocardia

A

• Nocardia
• Gram +, branched/filamentous rod, acid -fast staining (mycolic acid, carboyl-fuchsia staining), catalase +, OBLIGATE AEROBE, urease+
• Transmission: Found in soil
• Primarily effect IMMUNECOMPRIMISED pts, Men&raquo_space;> Women
○ Pulmonary: pneumonia + lung abscess/cavitary lesions
○ CNS: brain abscesses
○ Cutaneous: open wounds exposed to dirt, pyogenic response, indurated lesions
Tx: sulfonamides

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17
Q

• Histoplasmosis

A

• Histoplasmosis
○ R: bird/bat droppings, caves, farmers
§ Geography: midwestern/central USA, mississippi valley
§ Transmission: respiratory system
○ C: systemic, asymptomatic, can cause pnemonia from granuloma formation-> calcify nodules with fibrotic scarring, resembles TB, erythema nodosum on legs
§ Dimorphic: mold in the cold, yeast in the heat
§ Immune compromised disseminated form: hepatosplenomegaly, targets reticulo-endothelial system
○ H: macrophages filled with intracellular oval bodies
§ Stain with KOH prep
§ Much smaller than RBC
Dx: serum rapid antigen test, urine rapid antigen test

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18
Q

Pertussis toxin mechanism

A

Pertussis: AB toxin exists as hexamer, ADP ribosylates a host cell G protein –> increases cAMP levels

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19
Q

• African sleeping sickness

A

• African sleeping sickness
○ African Trypanosomiasis: trypanosoma brucei gambiense (most common) trypanosoma brucei rhodesiense (severe disease)
○ Bite reaction from Tsetse fly: chancre forms 1-3 weeks after bite, leaves no scar
○ 1st stage: hemolymphatic infection
○ 2nd stage: meningoencephalitis
○ Epimastigotes: in fly, transforms into trypomastigote, visualize trypomastigotes in human blood
○ “Antigenic variation” with Variant surface glycoproteins (VSGs) therefore block host immune system from getting at invariant antigens and creates cyclical waves of parasitemia
§ Recycling of VSGs that get recognized by immune system
Testing: Trypomastigotes on blood smear or in CSF

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20
Q

• Escherichia coli

A

• Escherichia coli
• Gram - coccobaccili, lactose fermenter, catalase +, encapsulated, k-antigen on capsule, grows green on EBM agar, fimbrae/pili
• Diseases:
○ #1 UTIs: caused by fimbrae/pili
○ #1 gram negative sepsis: mediated by LPS endotoxin
○ Meningitis in neonates (Requires K antigen)
○ EHEC: undercooked meat, bloody diarrhea, does not ferment sorbitol, can cause HUS
§ Toxin: Shiga-like toxin: inhibits ribosomes at 60S
§ O157:H7 serotype involved in outbreaks
○ ETEC: traveler’s watery diarrhea, transmitted from dirty water, “montezumas revenge”
§ Toxin: heat labile: increased cAMP (like cholera toxin)
§ Toxin: heat stable: increased cGMP
Tx:

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21
Q

Transferrin

A

Transferrin: binds to surface receptor on gonorrhea, iron is removed and internalized

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22
Q

• Human metapneumovirus:

A

• Human metapneumovirus: sRNA-, pneumoviridae
• #2 most common lower resp tract infection in children, less severe than RSV
• Dx: RT-PCR
No Tx, No Vax

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23
Q

• Streptococcus agalactiae

A

• Streptococcus agalactiae
• Gram+ cocci, bacitracin-resistant, hippurate+, beta-hemolytic, CAMP test + (increasing zone of hemolysis when plated with staph aureus), encapsulated, group B strep
• Transmission: mom->baby during vaginal delivery
• Diseases:
○ #1 Meningitis in neonates
○ Sepsis in neonates
○ Pneumonia
• Tx: penicillin for mom before delivery
Prevention: swab mom at 35 wks

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24
Q

• Rotavirus:

A

• Rotavirus: dsRNA, replicates in cytoplasm, naked, segmented (11), type of reovirus
• NSP4 toxin: secretory explosive water diarrhea
○ Increases chloride permeability–> watery diarrhea
○ Winter-time outbreaks
○ Children high risk for infections (#1 cause severe diarrhea in children)
• Tx: live attenuated oral virus vaccine
○ 1st dose: before 3 mo age
Vax side effect: Increases risk of intussusception (telescoping of bowel)

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25
Q

Resistance: CRE

A

CRE (Carbapenem-resistantEnterobacteriaceae): efflux of drug OR loss of outer membrane porins

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26
Q

• Life cycle of Schistosoma/Bilharzia/snail fever

A

• Life cycle of Schistosoma/Bilharzia/snail fever
• Trematode (flatworm):
S. Mansoni: Intestinal, stabbing spike, –> portal hypertension
S. Japonicum: Asian intestinal, round –> portal hypertension
S. Haematobium: urinary, lancet –> bladder cancer
• Cercariae penetrate the skin–> blood vessels of bowel/rectum or bladder, mature into sexual adults and make eggs –> eggs passed from humans into water, eggs hatch and release miracidia–> miracidia penetrate snail tissue and mature into sporocysts –> cercariae released into water
Dx: urine eggs

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27
Q

• Kirby-Bauer susceptibility testing:

A

• Kirby-Bauer susceptibility testing: disk diffusion, spread known amount of bacteria evenly on a plate, incubate, organisms grows or dies depending on its MIC and diffusion rate of antibiotic, larger area of killing, greater suspetibility
• MIC where growth meets no growth on the E strip
Some subjectivity

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28
Q

• Blastomycosis

A

• Blastomycosis
○ R:
§ Geography: southern, eastern USA, great lakes/ohio river valley
§ Transmission: inhalation of spores
○ C: patchy alveolar infiltrate on xray, lesions or cavities in lung, acute or chroni pneumonia
§ Can spread “systemic” in immunocompromised: disseminates to skin and bone (osteomyelitis)
§ Dimorphic: mold in cold, yeast in heat
H: broad based budding, same size as RBC, urine antigen test

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29
Q

• Mycobacterium leprae

A

• Mycobacterium leprae
• Thrives in cool temperatures (explaining predilection for extremities), acid-fast staining (mycolic acids)
○ Reservoir: armadillos, Hansen’s Disease
• Tuberculoid form: Th1 response with cell mediated immunity, able to contain bacteria in macrophages, mild disease,
○ well demarcated, hairless, skin lesion
○ Lepromin skin test: test for immune reaction, positive: demonstrates good cell mediated response, like PPD skin test
• Lepromatous form: Th2 mediated- humoral response, prevents containment of bacteria within macrophages, causes humoral response
○ Transmission: unknown, perhaps resp droplets, human-human
○ Neuropathy symmetric with glove stocking pattern
○ Numerous poorly demarcated skin lesions on extensor surfaces of extremities
○ Leonine faces
• Tx:
○ Tuberculoid: dapsone, rifamapin 6 months
Lepromatous: dapsone, rifampin, clofazimine 2-5 years

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30
Q

• Pseudomonas aeruginosa

A

• Pseudomonas aeruginosa
• Gram - bacilli, grape-like odor, catalase +, oxidase +, produces blue/green pigments when plated, obligate aerobe, encapsulated
○ Catalase + : therefore extra susceptible to chronic granulomatous disease
• Transmission: environment contaminate
• Diseases:
○ Hot-tub folliculitis: puritic papular
○ Ecthyma gangrenosum: Cutaneous necrosis if gets into systemic circualtion
○ #1 Nosocomial Pneumonia
○ #1 Respiratory failure in CF patients: because Cl- channel dysfunctional
○ Nosocomial UTIs/catheter infections
○ Osteomyelitis: IVDU, diabetics
○ Burn patients: feared complication of burn wounds, often fatal
○ Otitis externa
• Toxins: Exotoxin A: ADP-ribosylates EF2
Treatment: Piperacillin, fluoroquinolones, aminoglycosides

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31
Q

Resistance: ESBL

A

• ESBL (Extended-spectrum beta-lactamases): produce beta-lactamase in periplasm that chews up the beta-lactams
○ Use combo- beta-lactam/beta-lactamase inhibitor drug combos
Carbapenems effective

32
Q

• Rhinovirus:

A

• Rhinovirus: pico virus family, RNA+, Naked,
• Transmission: respiratory system, acid labile (therefore cannot go thru GI tract), transmitted though fomites (yucky hands)
○ Attaches to ICAM-1 on host cells to enter
○ Grows best at 33C (slightly cooler than body), therefore found in upper resp. tract
• Translation: use host cell machinery–> polyprotein product, cleavage by viral packaged protease–> processed in cytoplasm
MANY different serotypes, therefore tough to make vaccine, common cold!

33
Q

• Herpes zoster vaccine:

A

• Herpes zoster vaccine: SHINGRX, adjuvanted recombinant vaccine, VZV glycoprotein plus t cell bosting adjuvant (our immune system gets worse when we get old and so shingles pops out when we age)
Shingles: reactivation of VZV from dermatomal ganglia

34
Q

• Streptococcus gallolyticus

A

• Streptococcus gallolyticus
• Gram + , alpha or gamma hemolytic, but classified as Group D strep within B-hemolytic streps
Blood stream infection associated with colon cancer

35
Q

• Cephalosporins:

A

• Cephalosporins: inhibits trans-peptidase enzyme (penicillin binding protein), therefore no cross linking of peptidoglycans, therefore no stability to cell wall
○ Similar to penicillin
○ Bacterialcidal
Time-dependent killing

36
Q

• Fluoroquinolones:

A

• Fluoroquinolones: disrupts DNA synthesis–> inhibit DNA gyrase and topoisomeraseIV–> inhibits protein synthesis
○ Bacterialcidal
○ Gram - most effective
Concentration dependent killing

37
Q

Respiration/Fermentation

A

• Respiration and fermentation
• Respiration: O2 electron acceptor of NO3-, happens between 2 cell membranes/wall, more efficient
• Lactose Fermentation: grows pink colonies on MacKonkeys Agar
○ E coli
○ Klebsiella pnemoniae
○ Enterobacteracie
○ Serratia
• Maltose fermentation: G. meningitidus yes, G. gorrorehea no
• Sorbitol fermentation: NOT EHEC, all other E. coli do
Mannitol fermentation: s. aureus, grows golden

38
Q

• Coxiella burnetii

A

• Coxiella burnetii
• Gram +, Obligate intracellular, SPORES
• Transmission: spores in dirt, survives animals GI tract and poops out spores, transmitted to humans via aerosolized transmission
○ Reservoir: farm animals
• Q fever: pneumonia, headache, fever, HEPATITIS
NO RASH

39
Q

• HHV-8:

A

• HHV-8: dsDNA, herpes virus,
• Unique: Kaposi Sarcoma (AIDS/immune suppression) = erythematous on nose, mucous membranes (Gi tract, hard palate), extremities
○ Pathogenesis: angiogenesis by dysregulating VEGF
• Infected B cells: primary effusion lymphoma
• Transmission: sexual contact/kissing
○ AIDS pts, Elderly Russian men, African folks
• Dx: microscopic, leukocytic infiltrate
○ Can be confused with Bartonella hensleae
Tx: antiretrovirals for HIV+ pts

40
Q

• Parvovirus B19:

A

• Parvovirus B19: naked virus, smallest DNA virus, ssDNA
• Transmission: respiratory droplet, TORCH
• Kids: Slapped-cheek rash/Fifth disease/Erethema infectiosa
○ Rash starts on face and moves downward
• Adults: join pain, arthritis, edema
• SCD: aplastic anemia, cobweb look
In Utero: Hydrops fetalis

41
Q

• Klebsiella pneumoniae

A

• Klebsiella pneumoniae
• Gram -, nosocomial (multi-drug resistance), lactose fermenter, non-motile, encapsulated, urease+
• Diseases: Pneumonia, UTIs
○ Alcoholics, Abscesses, Aspiration
§ Chest x ray for abscess might look like TB
• Unique: current jelly-sputum
Tx: Carbapenems

42
Q

• Mycobacterium avium-intracellulare

A

• Mycobacterium avium-intracellulare
• Atypical mycobacterial infection with nontuberculous mycobacteria caused by 2 species of mycos
○ Immunocompromised people more susceptible (AIDS) cystic fibrosis
• First presents as persistent cough, also fevers/diarrhea/malabsorption/weight loss,
• Common in the environment and infect when inhaled or swallowed
Macrolides used as prophylaxis in AIDS pts

43
Q

• Viral replication:

A

• Viral replication: ss(+)RNA vs ss(-)RNA vs dsDNA vs retrovirus
• -RNA: brings along own RNA polymerase, all single stranded, replicates in cytoplasm
○ EXCEPT: orthomyxovirus replicates in nucleus
• +RNA:
○ EXCEPT reovirus is double stranded
• DNA:

44
Q

• Respiratory syncytial virus:

A

• Respiratory syncytial virus: ssRNA-, enveloped
• #1 Lower respiratory tract illness in children: bronchiolitis, pneumonia, tracheobronchitis, croup
• Recurrent wheezing common following severe infection
• Dx: antigen detection, RT-PCR
• Prevention: monoclonal antibodies for high risk
Tx: nebulized hypertonic saline

45
Q

Cytochrome

A

Cytochrome: bacteria containing cytochrome c = oxidase positive

46
Q

• Francisella tularensis

A

• Francisella tularensis
• Gram - , coccobaccili (radish-like), Tularemia
• Transmission: rabbits (meat, direct contact) or through tick vector (dermacentor), CAN BE AEROSOLZIED
○ Tick bite ulcerates to introduce bacteria
○ Goes into macrophages
○ Travels through lymph system to reticular endothelial organs (lymph nodes)
○ Causes caseating necrosis
§ Swells and make palpable lymphadenopathy of nodes
§ Can spread systemically to other nodes
• Facultative intracellular
○ Therefore recovery depends on cell mediated immunity
○ Helps spread disease through body
Tx: aminoglycosides

47
Q

• Risk factors for disease acquisition: echinococcosis

A

• Risk factors for disease acquisition: echinococcosis
• Dog Tape worm, infected with cystic form of tapeworm, humans are intermediate host
○ Often asymptomatic, symptoms result from growth/expansion of cysts, cystic rupture can cause anaphylaxis
§ Within the cyst is the larvae
○ Dog injects cysts from viscera of sheep, humans accidentally ingest dog feces with eggs inside
Ranchers & Shepherds at risk, worldwide

48
Q

• Leishmaniasis

A

• Leishmaniasis
○ Visceral: Kala-azar, parasties in macrophages of reticuloendothelial system
§ Shows up like lymphoma, hepatosplenomegaly, amastigotes in macrophages in bone marrow
§ L. donavi, brazil, africa, indian
○ Cutaneous: skin, more common, world wide
§ Old world: limited to skin, self limited, scar
§ New world: L. braziliensis, L. mexicana, L. panamensis more difficult to treat, spread to mucosa (worry about this!)
○ Transmission: sand fly injects promastigote into human, transforms to amastigote in macrophages
§ Human to human, with sand fly in between, zoonotic
Testing: skin biopsy/culture

49
Q

Oxidase

A

Oxidase: oxidase test detects cytochrome c, measures ability of bacteria to oxidize and change color of NNdeimehtylppenlendiamine

50
Q

• Life cycle of Plasmodium spp.

A 
• Life cycle of Plasmodium spp.
	• Injected from mosquito as sporozoite--> infect hepatic macrophages, transform from schizont and asexual replication and release merozoites--> merozoite infects RBC--> mature into trophozoite (differences based on spp.) form either--> gametocytes (small proportion) to mosquito (sexual phase) OR schizont to merozoites to new RBC
	• Timelines:
		○ 1 day: P. knowlesi, monkey reservoir
		○ 2 days: p. vivax, p. ovale
		○ 3 days: p. malariae
Erratic: p. falciparum (kinda 48 hours)
51
Q

Pili

A

• Pili/fimbrae: long thin filamentous, all over surface of cell, composed of pilin, mediate adherence to host tissues, pili bind to receptors that consist of sugar resides on glycolipids/glycoproteins in the host cell, therefore ay types of pili, determines tissues specificity of many bacterial pathogens
• Sex pili: important in bacterial conjugation
Changing expression of pili: phase varition or antigenic variation

52
Q

• Glycopepetides:

A

• Glycopepetides: binds to d-ala-d-ala and blocks transpeptidase activity
○ Ex: vancomycin
Bacterialcidal

53
Q

Antiretroviral therapy targets:

A

Antiretroviral therapy targets: two nucleoside analogues plus integrase inhibitor or protease inhibitor

54
Q

Concentration- versus time-dependent killing

A

• Concentration: work best when concentration is very high relative to the MIC,
○ cmax/mic
○ High-dose or extended interval dosing
○ There is a time frame when cmax/mic is very high, but also a “post-antibiotic effect” interval where drug concertation decrease to levels below the MIC and there is persistent suppression of growth
§ The high the drug concentration the longer the duration of the PAE and the smaller the residual bacterial population when the next dose is given
• Time: “Time above the MIC” hours time/mic, want more than 40-50% of time usually
Alternative dosing to maximize time/MIC

55
Q

• Candidiasis

A

• Candidiasis
○ R: normal flora
○ C:
§ Baby: severe diaper rash
§ Oral: immunocompromised or steroids, can scrape off white mucosa
§ Esophagitis: AIDS defining illness, white psudomembranese, CD4 count 100
§ Vaginal candidiasis: diabetics, antibiotics, birth control
□ Does not change pH of secretions (4 pH)
§ Endocarditis: tricuspid valve, IVDU
§ Systemic: dimorphic, yeast form with pseudohypi in cold (20C), germ tubes in heat (37C)
○ H: catalase + (individuals with chronic granulomatous disease esp. suseptible)
KOH prep

56
Q

TSST-1

A

TSST-1: exotoxin, toxic shock syndrome, staph aureus, super antigen

57
Q

• Chagas disease

A

• Chagas disease
○ American Trypanosomiasis: T. cruzi, zoonotic, many animal hosts tough to eradicate, WESTERN HEMISPHERE
○ Transmission: kissing bug/reduviid bug, blood meal and deposits feces into the bite/eye
§ Inoculated as trypomastigote which circulates, can get taken up by another bug and complete life cycle in vector
□ Affinity for cardiac muscle and smooth muscle of GI tract
○ Disease: chagoma: inflammatory lesion at site of entry (Romana sign: swollen eye)
○ Disease: cardiomyopathy, pseudocyst filled with amastigotes within cardiac tissue
○ Disease: megacolon, megaesophagus, loss of muscle tone
Testing: Blood smear for trypanosomes, Serology, heart histology

58
Q

Ebola virus vaccine:

A

Ebola virus vaccine: vaccine in development, it works, moAB

59
Q

• Antifungal agent mechanism of action

A

• Antifungal agent mechanism of action
• Amphotericin B: polyene: binds ergosterol, disrupts fungal cell membrane (like penicillin but make if FUNgi), significant toxicity
• Azoles: inhibit ergosterol synthesis, broad spectrum, safer
• Allylamines: terbinafine: inhibits squalene epoxidase (eralier step in the sterol synthesis)
• Echinocandins: inhibit cell wall glucan synthesis, impairs cell wall stress tolerance
○ First choice empiric anti fungal in hospital, IV
Fungal cell wall: ergosterol vs. Mammalian cell wall: cholesterol

60
Q

Gram-positive v. Gram-negative:

A

Gram-positive v. Gram-negative: gram+ takes up crystal violet stain in cell wall based on high peptidoglycan content

61
Q

• Staphylococcus saprophyticus

A

• Staphylococcus saprophyticus
• Gram + cocci, novobiocin-resistant, catalase +, urease +, coagulase -
Diseases: UTIs, especially young sexually active women

62
Q

• Viridans streptococci

A

• Viridans streptococci
• Gram +, optochin-resistant, alpha-hemolytic, bile-insoluble/resistant, NOT encapsulated
• Diseases: dental caries
○ Subacute endocarditis of damaged heart valves (most commonly mitral valve)
§ Pathogenesis: adhere to fibrin platelet aggregates by producing dextrans that make the bugs stick
Tx: Macrolides, Cephtriaxone

63
Q

• Listeria

A

• Listeria
• Gram + baccili, Beta-hemolytic, survives at cold temperatures
• Transmission: soft cheese/milks, pregnant mom->baby
• Unique: flagella outside cell tumbling motility, inside cells use actin rockets and propel from one cell to another without leaving (Immune evasion)
• Unique: pregnant women more susceptible, DON’T EAT SOFT CHEESE, can be passed to baby or early preg. Terminate
• Unique: babies and old people especially susceptible
• Baby: 3rd common cause neonate meningitis
Tx: Ampicillin

64
Q

• Influenza A and B viruses

A

• Influenza A and B viruses: orthomyxovirus, RNA-, enveloped
• Unique: replicates inside the nucleus, segmented (therefore antigenic shift/drift)
○ Antigenic drift: point mutations in genome, slighlty altered (new flu shot needed), responsible for seasonal flu
○ Antigenic shift: RNA shared between different species (H and N reassortment), responsible for pandemics
§ A: pandemic/epidemic, drift and shift
§ B: endemic outbreaks, drift
○ Hemagglutinin (HA): glycoprotein on surface of influenza viruses, binds to sialic acids on upper resp. tract., causes RBCs to clump together in test tubes
§ HA antigens: H1, H2, H3, etc. determines cell tropism (cells that can be infected by virus)
○ M2 protein: needed to create proper pH for viral encoding
§ Amantadine/rimantadine inhibit M2, old treatments for FluA
○ Neuroaminidase (NA): cleaves sialic acid to release newly formed virions from infected cell
§ NA inhibitors: oseltamivir/anamivir
○ Transmission: resp. droplets, dec-feb
§ Give Vax in october
□ Live attenuated nasal spray
□ Injectable: killed version
○ Pneumonia: major complication, staph aureus common culprit
○ Aspirin: contraindicated in children with viral illnesses: REYES SYNDROME: fatty liver/liver failure/encephalitis
§ Uncouples ETC in hepatic mitochondria
• RT-Ascending paralysis from Guillain-Barre Syndrome associated with vax
• Dx: rapid antigen test, RT-PCR

65
Q

• Mycobacterium tuberculosis

A

• Mycobacterium tuberculosis
• Mycobacterium, acid-fast stained because of mycolic acids (carboyl fuschia stain), cultures very slowly, requires Lowenstein-Jensen media, obligate AEROBE, cell wall also has
• Transmission: respiratory droplets, human to human, once infected lives in macrophages
• Virulence:
○ Cord factor: glycolipid, serpentine shape, CRITICAL FOR Pathogenicity, sticky cell wall, once penetrates macrophages and induces TNFa, granuloma forms and remains walled off inside
○ Sulfatides: prevent phagolysosome fusion, creates incompetent secondary lysosomes/phagosomes in macrophages and allows TB to persist inside
• Primary infection: infects lungs in middle lung lobes and involves hilar lymph node
○ Ghon complex: hilar lymphadenopathy + peripheral granulomatous lesion in middle/lower lung lobe
○ Tubercules: caseating granuloma, langerhans giant cells (activated macrophages) make walled off scarred area filled with necrotic macrophages
○ Symptoms: prolonged fever, most causes resolve by fibrosis and becomes latent infection, mostly children effected
§ Will have positive PPD, type 4 hypersensitivity test
□ can be positive in active infection, latent, or BCG vaccines
• Disease paths after primary infection:
1. Healed latent infection: resolve by fibrosis
2. Miliary TB: multi-organ failure, can seed multiple organs, lethal possible
3. Reactivation of latent infection: 5-10% of people, immune suppression downregulates TNFa allowing the TB to escape the walled off granuloma and reactivate
i. Therefore: when starting patients on TNFa inhibitors, screen for TB first
ii. Reactivation: upper lobes, 1. cough, 2. night sweats, 3. hemoptysis
1) TNFa: promotes wasting, produced in response to cord factor
2) Pott’s disease: spinal column, damages vertebral bodies
3) CNS invovlement: cavitary lesion with tuberculoma
• Tx: rifampin, isoniazid, pyrazinamide, ethambutol
Prophylaxis: Rifampin, isoniazid (9 months!)

66
Q

• Therapeutic drug monitoring:

A

• Therapeutic drug monitoring: most commonly for vancomycin and tobromycin, want to avoid toxicity
• Especially important in obesity and renal impairment
• Trough monitoring
• Substantial interpatient variability exists in serum concentration on standard drugs
• Small diff between therapeutic and toxic doses
You need an accurate asasy to measure this

67
Q

Capsules

A

Capsules: made of water, aids in avoiding the immune system/opsonization/complement activation

68
Q

• Coccidiodomycosis

A

• Coccidiodomycosis
○ R:
§ Geography: southwestern USA
§ Transmission: inhalation of spores in dust, increased risk during dust storms/earthquakes
○ C: cough, fever, arthralgia, some radiographics may show cavities or nodeules some will be unremarkable, erythema nodosum on shins (robust immune response so only in healthy people)
§ Immunecompromised: disseminate to bone, skin, lung, meningitus
§ Dimorphic: mold in cold, spheriol of endospores in bodies -> ruptures and releases, larger than RBCs
H: KOH stain/culture, serology IgM vs cocci

69
Q

Catalase

A

Catalase: reduces H2O2 into H2O and O2

70
Q

Siderophore

A

Siderophores: remove iron from host molecules and take up into bacterial cells

71
Q

Superoxide dismutase

A

Superoxide dismutase: degrades superoxide to hydrogen peroxide

72
Q

Toxic Shock Syndrome mechanism

A

toxic shock syndrome: superantigen, sticks APC MHCII and CD4+ T cell together, constitutive activation, cytokine release, tissue damage

73
Q

• Proteus mirabilis

A 
• Proteus mirabilis
	• Gram - rod, flagellates, swarming-motility, fishy-odor, urease + (responsible for forming of struvite stones!)
	• Diseases:
		○ UTIs
		○ Kidney stones: stag horn calculi
Tx: sulfonamides
74
Q

• Wolbachia

A

• Wolbachia
• Gram - Endosymbiont, most significant in oncocerca volvulus (transmit by black fly), the increased river blindness is associated with increased wolbachia present, generates much inflame response when the filariae die and release wolbaccie
○ Present in W. bancrofti, B. Malayi, O. volvulus
○ NOT PRESENT IN LOA LOA
Tx: doxycycline kills off wolbachia without killing the microfilariae, but reduces blindness

75
Q

• Streptococcus pneumoniae

A

• Streptococcus pneumoniae
• Gram + lancet-diplo cocci, optochin sensitive, encapsulated, alpha-hemolytic, bile-soluble (cannot grow in bile)
• Diseases: #1
○ M-eningitus
○ O-titis media
○ P-nemonia: community-acquired, rust colored sputum, lower lobe
○ S-inusitis:
• Virulence:
○ polysacc capsule
○ IgA protease
• Unique: SCD pts particularly suseptible
• Tx: Macrolide, Cephtriaxone
• Prevention:
○ Adult vax: 23 valent, IgM, T-cell independent response
Children vax: 7 valent, IgG, conjugated polysac to a protein to make more robust immune response with IgG

76
Q

• Norovirus:

A

• Norovirus: ssRNA+, naked, one long polyprotein that is cleaved by viral proteases, replicates in cytoplasm
• Calicivirus family
• Outbreaks/Transmissions: cruises, close contact of humans, young children/schools/daycares, shellfish
Diarrheal illness: viral gastroenteritis, explosive watery diarrhea

77
Q

Peptidoglycan

A

Peptidoglycan: protein made up of alternating NAG/NAM

Foundations 3 (6 decks)

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