Microbiology- First Aid Flashcards
Bacteria that do not Gram stain well
Treponema, Mycobacteria, Mycoplasma, Legionella pneumophila, Rickettsia, Chlamydia
Giemsa Stain
Chlamydia, borrelia, Rickettsiae, Trypanosomes, Plasmodium
PAS Stain
Tropheryma whipplei
Ziehl-Neelsen
Nocardia, Mycobacterium (acid fast)
India ink
Crytococcus neoformans
Silver stain
Legionella, Helicobacter pylori, pneumocystis
Obligate Aerobes
Nocardia, Pseudomonas, Mycobacterium tuberculosis
Obligate Anaerobes
Clostridium, Bacteroides, Actinomyces
Obligate intracellular
Rickettsia, Chlamydia
Facultative intracellular
Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, Yersinia pestis
Encapsulated bacteria
Strep pneumoniae, haemophilus influenzae type B, Neisseria meningitidis, Escherichia coli, Salmonella, Klebsiella pneumoniae, group B strep
Catalase positive
Pseudomonas, Listeria, Aspergillus, Candida, E.coli, S. aureus, Serratia
Urease positive
Cryptococcus, H. pylori, Proteus, Ureaplasma, Nocardia, Klebsiella, Staph epidermis, Staph saprophyticus
Pigment producing bacteria
Actinomyces israelii (yellow granules) Staph aureus (yellow) Pseudomonas aeruginosa (blue-green pigment) Serratia marcescens (red pigment)
Effects of endotoxin (lipid A- mediated)
fever, hypotension, edema, neutrophil, chemotaxis, DIC
Toxins whose genes are encoded by a phage
shiga-like toxin, botulinum, cholera, diptheria, erythrogenic toxin (strep pyogenes)
Novobiocin
Staph Epidermidis is sensitive; Staph saprophyticus is resistant
Optochin
Strep viridans is resistant; strep pneumoniae is sensitive
Bacitracin
group B strep (agalactiae) are resistant; group A strep (pyogenes) are sensitive
Both group A and group B are beta-hemolytic
Staph epidermidis
infects prosthetic devices and IV catheters by producing adherent biofilms
Staph saprophyticus
2nd leading cause of uncomplicated UTI
Strep pneumoniae
meningitis, otitis media, pneumonia, sinusitis, alpha-hemolytic
Viridans group streptococci
Strep mutans- dental caries
Strep sanguinis- subacute bacterial endocarditis
Strep pyogenes
pharyngitis, cellulitis, impetigo, scarlet fever, toxic shock-like syndrome, necrotizing fasciitis, rheumatic fever, acute glomerulonephritis
Jones criteria for rheumatic fever
polyarthritis, carditis, subq nodules, erythema marginatum, sydenham chorea
Scarlet Fever
scarlet rash with sandpaper-like texture, strawberry tongue, circumoral pallor
Strep agalactiae
colonizes vagina causing pneumonia, meningitis, and sepsis in neonates
Enterococcus faecalis and faecium
penicillin G resistant, UTI, biliary tract infections, subacute endocarditis (post-GU/GI procedures)
Strep bovis
colonizes the gut, can cause bacteremia and subacute endocarditis in colon cancer patients
Corynebacterium diphtheriae
AB exotoxin ADP-ribosylates EF-2
Symptoms include pseudomembranous pharyngitis with lymphadenopathy, myocarditis, and arrhythmias
Spore-forming bacteria
Bacillus anthracis, Clostridium perfringens, Clostridium tetani, Bacilus cereus, Clostridium botulinum, Coxiella burnetii
Anthrax
Bacillus anthracis, a gram + spore-forming rod that is the only bacterium that contains a polypeptide capsule
Cutaneous anthrax
boil-like lesion–> ulcer with black eschar
Pulmonary anthrax
inhalation of spores–> flu-like symptoms that rapidly progress to fever, pulmonary hemorrhage, mediastinitis, and shock
Bacillus cereus
nausea and vomiting, watery nonbloody diarrhea, reheated rice syndrome
Listeria monocytogenes
- acquired by ingestion of unpasteurized dairy products and deli meats, via transplacental trasmission, or by vaginal transmission during birth
- only gram + to produce LPS
- causes amnionitis, septicemia, spontaneous abortion, granulomatosis infantiseptica, neonatal meningitis, meningitis in immunocompromised patients, mild gastroenteritis
Types of mycobacteria and their findings
Tuberculosis- TB
Kansassi- pulmonary TB like symptoms
Avium-intracellulare- disseminated non TB disease in AIDS
TB symptoms
fever, night sweats, weight loss, and hemoptysis
Lepromatous M. Leprae
diffuse infection over skin, leonine facies, communicable, humoral Th2 response
Tuberculoid M. Leprae
limited to a few hypoesthetic hairless skin plaques, characterized by cell-mediated Th1- type response
Lactose-fermenting enteric bacteria
Citrobacter, Klebsiella, E.coli, Enterobacter, Serratia
Haemophilus influenzae
Epiglottitis, meningitis, otitis media, pneumonia
H. influenzae culture
Chocolate agar with factor V (NAD+) and X (hematin)
Legionella pneumophila
- Gram negative rod
- Grows on charcoal yeast extract culture with iron and cysteine
- Aerosol transmission from environmental water source
- Severe pneumonia, fever, GI and CNS symptoms (Legionnaires’ disease)
- mild flu-like syndrome (Pontiac fever)
Hemolytic uremia syndrome
anemia, thrombocytopenia, acute renal failure
Klebsiella
- Intestinal flora that causes lobar pneumonia in alcoholics and diabetics when aspirated
- red currant jelly sputum
- gram negative lactose fermenting rods
Salmonella typhi
- Typhoid fever
- Rose spots on abdomen, fever, headache, and diarrhea
- Remain in gallbadder (carrier state)
Campylobacter jejuni
- oxidase positive
- bloody diarrhea
- fecal oral transmission
- common antecedent to Guillain-Barre syndrome and reactive arthritis
Vibrio Cholera
- oxidase positive
- comma shaped
- rice water diarrhea that activates Gs (increases cAMP)
Yersinia enterocolitica
- transmitted from pet feces, contaminated milk, pork
- mesenteric adenitis that can mimic Crohn disease or appendicitis
Helicobacter pylori
- gastritis and peptic ulcers (especially duodenal)
- curved rod that is catalase, oxidase and urease positive
- triple therapy: PPI, clarithromycin, amoxicillin or metronidazole
Spirochetes
Borrelia (biggest), Leptospira, Treponema
Leptospira interrogans
- transmitted by water contamination of animal urine
- leptospirosis: flu-like, jaundice, photophobia with conjunctival erythema without exudate
- Weil disease: severe form with jaundice, azotemia, fever, hemmorhage, and anemia
Lyme disease
- Borrelia burgdorferi
- Ixodes tick
- Initial symptoms: erythema migrans, flu-like symptoms, facial nerve palsy
- monoarthritis, migratory polyarthritis, AV nodal block, encephalopathy, facial nerve palsy, polyneuropathy
- doxycycline ceftriaxone
VDRL false positives
mononucleosis, EBV, hepatitis, drugs, SLE, leprosy
Jarisch-Herxheimer
flu-like syndrome after abx are started due to killed bacteria releasing pyrogens
Gardnerella vaginalis
- vaginosis (fishy smell of vagina, nonpainful, associated with sexual activity)
- vaginal epithelial cells covered with gardnerella
- tx metronidazole, clindamycin
Rickettsia rickettsii
- tick vector
- Rocky mountain spotted fever
- rash starts in palms and soles, spreads to trunk, palms, and soles
- headache, fever, rash
Rickettsia typhi/prowazekii
-rash starts centrally and spreads out, spares palms and soles
Ehrlichia chaffeenis
- tick vector
- Ehrlichiosis
- monocytes with morulae (berry like inclusions in the cytoplasm)
Anaplasma
- tick vector
- granulocytes with morulae in cytoplasm
- Anaplasmosis
Coxiella burnetii
- spores inhaled as aerosol
- pneumonia
- no rash
Mycoplasma pneumoniae
- pneumonia (insidious onset, headache, nonproductive cough, patchy or diffuse interstitial infiltrate)
- grown on Eaton agar
- IgM
- Tx, macrolide, doxycycline, fluoroquinolone
Systemic mycoses
- pneumonia
- dimorphic (mold in cold, yeast in heat)
- tx is fluconazole or itraconzaole for local infection and amphotericin B for systemic infection
- mimic TB (granuloma formation)
Tinea versicolor
- Malassezia furfur
- hypo/hyperpigmented patches
- hot/humid weather
- spaghetti and meatball appearance
- topical miconazole, selenium sulfide
Giardiasis
- Giardia lamblia
- bloating, flatulence, foul-smelling, fatty diarrhea
- cysts in water
- trophozoites or cysts in stool
- metronidazole
Amebiasis
- Entamoeba histolytica
- bloody diarrhea
- liver abscess
- RUQ pain (rupture of submucosal abscess of colon)
- cysts in water
- trophozoites (with RBC’s in the cytoplasm)
- cysts in stool
- metronidazole or iodoquinol (for asymptomatic cyst passers)
Cryptosporidium
- severe diarrhea in AIDS
- water diarrhea in immunocompetent
- oocysts in water
- acidfast stain
- nitazoxanide in immunocompetent
Toxoplasmosis
- Toxoplasma gondii
- brain abscess in HIV
- chorioretinitis, hydrocephalus, intracranial calcifications
- cysts in meat or oocysts in cat feces, placental transmission
- serology or biopsy (tachyzoite)
- sulfadiazine+pyrimethamine
Naegleria fowleria
- rapidly fatal meningoencephalitis
- swimming in freshwater lakes (enters via cribiform plates)
- ameobas in spinal fluid
- amphotericin B
Trypanosoma brucei
- African sleeping sickness (enlarged lymph nodes, recurring fever, somnolence, coma)
- antigenic variation
- tsetse fly
- suramin for blood-borne disease or melarsoprol for CNS penetration
Babesia
- babesiosis
- fever, hemolytic anemia
- Ixodes tick, northeastern U.S.
- blood smear either ring or Maltese cross
- Tx, atovaquone, azithromycin
Trypanosoma cruzi
- Chagas disease
- dilated cardiomyopathy, megacolon, megaesophagus
- reduviid bug
- Tx, benznidazole, nifurtimox
Leishmania donovani
- visceral leishmaniasis
- spiking fevers, hepatosplenomegaly, pancytopenia
- sandfly
- macrophages containing amastigotes
- Tx, amphotericin B, sodium stibogluconate
Trichomonas vaginalis
- vaginitis
- foul smelling, greenish discharge, itching and burning
- trophozoites on wet mount
- metronidazole for patient and partner
Enterobius vermicularis (pinworm)
- fecal oral
- intestinal infection causing anal pruritis
- scotch tape test
- bendazoles or pyrantel pamoate
Ascaris lumbricoides (giant roundworm)
- fecal oral
- intestinal infection
- bendazoles or pyrantel pamoate
Strongyloides stercoralis
- larvae in soil penetrate the skin
- intestinal infection causing vomiting, diarrhea, epigastric pain
- ivermectin or albendazole
Ancylostoma duodenale, Necator americanus (hookworm)
- larvae penetrate skin
- intestinal infection causing anemia by sucking blood from intestinal walls
- bendazoles or pyrantel pamoate
Onchocerca volvulus
- female blackfly
- hyperpigmented skin and river blindness
- ivermectin
Loa loa
- deer, horse, mango fly
- swelling in skin, worm in conjunctiva
- diethylcarbamazine
Wuchereria bancrofti
- female mosquito
- blocks lymphatic vessels
- elephantiasis (takes 9 mo to 1yr)
- diethylcarbamazine
Toxocara canis
- fecal oral
- visceral larva migrans
- albendazole or mebendazole
Taenia solium
- ingestion of larvae encysted in undercooked pork, eggs
- intestinalinfection
- cysticercosis, neurocysticercosis
- praziqunatel, albendazole
Diphyllobothrium latum
- ingestion of larvae from raw freshwater fish
- vitamin B12 deficiency (pernicious anemia)
- praziquantel
Echinococcus granulosus
- ingestion of eggs from dog feces
- hydatid cysts in liver, anaphyalxis if antigens released
- albendazole
Schistosoma
- snails are host, cercariae penetrate skin of humans
- liver and spleen granulomas, fibrosis and inflammation
- chronic infection can lead to squamous cell carcinoma of the bladder (painless hematuria)
- praziquantel
Clonorchis sinensis
- undercooked fish
- biliary tract inflammation, pigmented gallstones, associated with cholangiocarcinoma
- praziquantel
Live attenuated vaccinations
smallpox, yellow fever, chickenpox, Sabin polio virus, MMR, intranasal influenza
Inactivated vaccinations
rabies, injected influenza, salk polio, HAV vaccines
Recombinant vaccinations
HBV, HPV (types 6,11,16,18)
Naked (nonenveloped viruses)
Papillomavirus, adenovirus, parvovirus, polyomavirus, calicivirus, picornavirus, reovirus, hepevirus
Hepadnavirus (HBV)
- acute or chronic hepatitis
- vaccine
- reverse transcriptase
Adenovirus
- febrile pharyngitis
- acute hemorrhagic cystitis
- pneumonia
- conjunctivitis (pink eye)
Parvovirus (B19)
- aplastic crises in sickle cell disease
- “slapped cheeks” rash (erythema infectiosum)
- RBC destruction in fetus–> hydrops fetalis and death
- pure RBC aplasia
- rheumatoid arthritis
Papillomavirus (HPV)
- warts (1,2,6,11)
- cervical cancer (16,18)
Polyomavirus
- JC virus causing progressive mutlifocal encephalopathy
- BK virus in kidney transplant patients
Poxvirus
- small pox
- cowpox
- molluscum contagiosum (flesh colored dome lesions with central umbilicated dimple)
Negative-stranded RNA viruses (RNA-dependent RNA polymerase)
Arenavirus, Bunyavirus, Paramyxovirus, Orthomyxovirus, Filovirus, Rhabdovirus
Segmented viruses (RNA)
Bunyavirus, orthomyxovirus, arenavirus, reovirus
Picornavirus
- Poliovirus, Echovirus, Rhinovirus, Coxsackievirus, HAV
- polyprotein
- viral meningitis (except rhinovirus)
- enterovirus (except rhinovirus)
Rhinovirus
- picornavirus
- noneveloped RNA virus
- destroyed by stomach acid
- common cold
Yellow fever virus
- flavivrus (arbovirus)
- Aedes mosquitoes
- high fever, black vomitus, jaundice
Rotavirus
- infantile gastroenteritis
- segmented dsRNA virus (reovirus)
- villous destruction with atrophy leads to decreased absorption of Na and loss of K
Influenza
- orthomyxovirus
- enveloped, negative ssRNA
- hemagglutinin promotes viral entry, neuraminidase promotes progeny virion release
Rubella virus
- togavirus
- fever, postauricular lymphadenopathy, arthralgias, fine rash
- TORCHES (blueberry muffin appearance)
Paramyxovirus
- parainfluenza (croup)
- mumps
- measles
- RSV (bronchiolitis, pneumonia)
- F (fusion) protein that transforms respiratory epithelial cells into multinucleated cells
Measles
- paramyxovirus
- Koplik spots on buccal mucosa
- maculopauplar rash
- sequelae include subacute sclerosing panencephalitis, encephalitis, giant cell pneumonia
- cough, rhinitis, conjunctivitis
Mumps
- paramyxovirus
- parotitis, orchitis, viral meningitis
Rabies
- rhabdovirus
- bullet shaped virus
- Negri bodies (cytoplasmic inclusions in purkinje cells)
- fever, malaise–> agitation, photophobia, hydrophobia–> paralysis, coma–> death
Prions
- conversion of PrPc–> PrPsc (beta-pleated)
- spongiform encephalopathy, dementia, ataxia, death
Toxoplasma gondii (TORCHS)
neonatal chorioretinitis, hydrocephalus, intracranial calcification
Rubella (TORCHS)
PDA or pulmoanry artery hypoplasia, cataracts, deafness, blueberry muffin rash
CMV (TORCHS)
hearing loss, seizures, petechial rash, blueberry muffin rash
HSV-2 (TORCHS)
encephalitis, herpetic lesions
Syphillis (TORCHS)
stillbirth, hydrops fetalis, facial abnormalities such as notched teeth, saddle nose, short maxilla, saber shins and CV VIII deafness
Penicillin G/V Mechanism
- Bind penicillin-binding proteins (transpeptidases)
- block transpeptidase cross-linking of peptidoglycan
- activate autolytic enzymes
Penicillin G/V use
gram positive (S. pneumoniae, S. pyogenes, Actinomyces), N. meningitis, T. pallidum
Ampicillin, amoxicillin
- Bind penicillin-binding proteins (transpeptidases)
- block transpeptidase cross-linking of peptidoglycan
- activate autolytic enzymes
Ampicillin, amoxicillin use
- Penicillin coverage
- H. influenzae, E.coli, L. monocytogenes, P. mirabilis, Salmonella, Shigella
Oxacillin, nafcillin, dicloxacillin
- Penicillinase (beta-lactamase) resistant
- Used for S. aureus except for MRSA
Ticarcillin, piperacillin
- Penicillin use and coverage
- Additional coverage of pseudomonas and gram negative rods
Beta lactamase inhibitors
Clavulanic Acid, Sulbactam, Tazobactam
Cephalosporins
- beta lactam durgs
- less susceptible to penicillinases
- Listeria, Chlamydia, Mycoplasma, MRSA, Enterococci are not covered
Cefazolin, Cephalexin (1st generation)
- Gram positive cocci
- Proteus mirabilis
- E.coli
- Klebsiella pneumoniae
- S. aureus wound infection prophylaxis
Cefoxitin, cefaclor (2nd generation)
Gram positive cocci, H. influenzae, Enterbacter aerogenes, Neisseria, Proteus, E.coli, Klebsiella pneumoniae, Serratia marcescens
Ceftriaxone, cefotaxime, ceftazidime (3rd generation)
serious gram-negative infections resistant to other beta lactams
Cefepime (4th generation)
Pseudomonas and gram positive organisms
Ceftaroline (5th generation)
broad gram positive and gram negative coverage including MRSA but NOT pseudomonas
Aztreonam
- monobactam
- no allergic cross reactivity with penicillins
- prevents peptidoglycan cross-linking
- gram-negative rods
Carbapenems
imipenem, meropenem, ertapenem, doripenem
Note: imipenem is co-administered with cilastatin (an inhibitor of renal dehydropeptidase I to decrease inactivation by the kidney)
Carbapenems (use)
gram-positive cocci, gram-negative rods and anaerobes
Carbapenem toxicity
GI distress, skin rash, CNS toxicity (seizures)
Vancomycin mechanism
inhibits cell wall peptidogylcan formation by binding D-ala D-ala portion of cell wall precursors
Vancomycin use
gram positive only (MRSA, entercocci, C. difficile)
Vancomycin (toxicity)
nephrotoxicity, ototoxicity, thrombophlebitis, diffuse flushing aka Red Man syndrome
Aminoglycosides
gentamicin, neomycin, amikacin, tobramycin, streptomycin
Aminoglycosides mechanism
- bactericidal, inhibit formation of initiation complex and cause misreading of mRNA, also block translocation
- ineffective against anaerobes because requires O2 for uptake
Aminoglycosides toxicity
nephrotoxicity, neuromuscular blockade, ototoxicity, teratogen
Tetracyclines
tetracycline, doxycycline, minocycline
Tetracycline mechanism
bacteriostatic, bind to 30s and prevent attachment of amino-acyl tRNA
Tetracycline use
Borrelia burgdorferi, mycoplasma pneumonia, rickettsia, chlamydia (intracellular penetration)
Tetracycline toxicity
GI distress, discoloration of teeth and inhibition of bone growth in children, photosensitivity, contraindicated in pregnancy
Macrolides
azithromycin, clarithromycin, erythromycin
Macrolides mech.
inhibit protein synthesis by blocking translocation, binds the 23S rRNA of the 50S ribosomal subunit, bacteriostatic
Macrolides use
Atypical pneumonias (mycoplasma, chlamydia, legionella), STD (chlamydia) and gram positive cocci (pt’s with penicillin allergies)
Macrolides toxicity
GI dysmotility, Arrhythmia caused by prolonged QT, acute cholestatic hepatitis, rash, eosinophilia
Chloramphenicol mech.
blocks peptidyltransferase at 50s ribosomal subunit, bacteriostatic
Chloramphenicol use
meningitis (H. influenzae, N. meningitis, S. pneumoniae), Rickettsia rickettsii
Chloramphenicol toxicity
anemia, aplastic anemia, gray baby syndrome
Clindamycin mech.
blocks peptide transfer (translocation) at 50s subunit, bacteriostatic
Clindamycin use
anaerobic infections (Bacteroides, Clostridium perfringens), invasive Group A strep
Clindamycin toxicity
pseudomembranous colitis (C.dificile), fever, diarrhea
Sulfonamides mech
inhibit folate synthesis, inhibit dihydropteroate synthase
Sulfonamides use
gram-positive, gram-negative, nocardia, chlamydia
Sulfonamides toxicity
hypersensitivity, hemolysis if G6PD deficient, nephrotoxicity, photosensitivity, kernicterus, displace other drugs from albumin
Trimethoprim mech.
inhibits bacterial dihydrofolate reductase (dihydrofolic acid–> tetrahydrofolic acid)
Trimethoprim use
used in combination with sulfonamides for UTI’s, shigella, salmonella, pneumocystis jirovecii, pneumonia tx and prophylaxis and toxoplasmosis prophylaxis
Trimethoprim toxicity
megaloblastic anemia, leukopenia, granulocytopenia
Fluoroquinolones (-floxacin) mech.
inhibit DNA gyrase (topoisomerase II) and topoisomerase IV, bactericidal
Fluoroquinolones (-floxacin) use
gram-negative rods of urinary and GI tracts (pseudomonas), Neisseria, some gram-positive organisms
Fluoroquinolones (-floxacin) toxicity
- GI upset, superinfections, skin rashes, headache, dizziness, tendon rupture
- contraindicated in pregnant women, nursing women, and children<18 yr
Metronidazole mech.
- forms free radical toxic metabolites in the bacterial cell that damage DNA
- bactericidal, antiprotozoal
Metronidazole use
- Giardia, Entamoeba, Trichomonas, Gardnerella vaginalis, -Anaerobes (bacteroides, C. difficile)
- triple therapy with PPi and clarithromycin
Metronidazole toxicity
disulfiram-like reaction, headache, metallic taste
Isoniazid mech.
decrease synthesis of mycolic acids, bacterial catalase-peroxidase needed to convert isoniazid to active metabolite
Isoniazid Use
prophylaxis for M. tuberculosis
Isoniazid toxicity
neurotoxicity, hepatotoxicity
Rifamycins (rifampin, rifabutin) mech.
inhibits DNA-dependent RNA polymerase
Rifamycins (rifampin, rifabutin) use
- M. tuberculosis
- used for meningococcal prophyalxis
- prophylaxis for contacts with HiB
Rifamycins (rifampin, rifabutin) toxicity
minor hepatotoxicity, orange body fluids, enzyme (P-450) inducer
TB treatment drugs
Rifampin, isoniazid, pyrazinamide, ethambutol
Amphotericin B mech.
binds ergosterol, forms membrane pores that allow leakage of electrolytes
Amphotericin B use
- serious, systemic mycoses
- cryptococcus, blastomyces, coccidioides, histoplasma, candida, mucor
- concurrently supplement K and Mg
Amphotericin B toxicity
fever, chills, hypotension, nephrotoxicity, arrhythmias, anemia, IV phlebitis
Nystatin
topical, mouthwash form of amphotericin B
Azoles mech.
inhibit ergosterol synthesis by inhibiting the Cyp-450 enzyme lanosterol–> ergosterol
Azoles use
- local and less serious systemic mycoses
- chronic cryptococcal meningitis in AIDS patients
- candidal infections
- itraconazole for blastomyces, coccidioides, histoplasma
- clotrimazole and miconazole for topical fungal infections
Azoles toxicity
- testosterone synthesis inhibition (gynecomastia)
- liver dysfunction
Flucytosine mech
inhibits DNA and RNA biosynthesis by conversion to 5-fluorouracil by cytosine deaminase
Flucytosine use
systemic fungal infections (especially meningitis caused by Cryptococcus) in combination with amphotericin B
Flucytosine toxicity
bone marrow suppression
Echinocandins (caspofungin, micafungin, anidulafungin)
Mechanism: inhibits cell wall synthesis by inhibiting synthesis of beta-glucan
Use: invasive aspergillosi, candida
Toxicity: GI upset, flushing (histamine release)
Terbinafine
Mechanism: inhibits the fungal enzyme squalene epoxidase which inhibits lanesterol synthesis
Use: dermatophytoses (especially onychomycosis)
Toxicity: GI upset, headaches, hepatotoxicty, taste disturbance
Griseofulvin
Mechanism: interferes with microtubule function; disrupts mitosis; deposits in keratin-containing tissues
Use: oral treatment of superficial infections; inhibits growth of dermatophytes (tinea, ringworm)
Toxicity: teratogenic, carcinogenic, confusion, headaches, increased P-450, warfarin metabolism
Antiprotozoan therapy
pyrimethamine (toxoplasmosis), suramin and melarsoprol (T. brucei), nifurtimox (T.cruzi), sodium stibogluconate (leishmaniasis)
Chloroquine
Mechanism: blocks detoxification of heme into hemozoin; heme accumulates and is toxic to plasmodia
Use: treatment of plasmodia except for P. falciparum
Toxicity: retinopathy, retinitis
Zanamivir, oseltamivir
inhibit influenza neuraminidase
Ribavirin
Mechanism: inhibits synthesis of guanine nucleotides by competitively inhibiting inosine monophosphate dehydrogenase
Use: RSV, chronic hepatitis C
Toxicity: hemolytic anemia, teratogen
Acyclovir, famciclovir, valacyclovir mechanism
monophosphorylated by HSV/VZV thymidine kinase and not phosphorylated in uninfected cells to form guanosine analog thus inhibiting viral DNA polymerase by chain termination
Note: ganciclovir has similar mechanism for CMV
Foscarnet mechanism
viral DNA polymerase inhibitor that binds to the pyrophosphate-binding site of the enzyme
Note: used when -vir drugs fail
Cidofovir
Mechanism: preferentially inhibits DNA polymerase, does not require phosphorylation from virus kinase
Use: CMV retinitis, acyclovir-resistant HSV
Toxicity: nephrotoxicity
