Microbiology Flashcards
How are the plasmodium organisms transmitted?
Anopheles Mosquito
Classic Presentations of Plasmodium
Malair, fever, headache, anemia, splenomegaly
What are the fever cycles of the different plasmodium?
Falciparum: irregular
Vivax/Ovale: 48h cycle
Malariae: 72h cycle
How are plasmodium vivax/ovale and falciparum presented differently?
P. falciparum: severe; irregular fever patterns; parasitized RBCs occlude capillaries in brain (cerebral malaria), kidneys, lungs
P. vivax/ovale: 48 hr cycle; dormant form in liver
What are the diagnosis findings of plasmodium?
Blood smear, trophozoite ring form. RBC schizont with merozoites
Treatment for plasmodium (first line and resistant)
Chloroquine (blocks plasmodium heme polymerase)
Resistant, use mefloquine
Vivax/ovale: add primaquine for dormant form in liver (hypnozoite)
Babesia. Transmission, Presentation, Diagnosis and Treatment
Ixodes Tick (NE US). Fever and hemolytic anemia. Asplenia increase risk of severe disease.
Blood smear, ring form, “Maltese cross”
Quinine, clindamycin
Lyme disease. Pathogen. Transmission. Presentation (Stages). Treatment
Borrelia burgdorferi (Ixodes tick, mice/deer, NE US). Large, microaerophilic spirochete. Stage 1: erythema chronicum migrans (bull's eye red rash with central clearing), flulike symptoms. Stage 2: Bell's palsy, cardiac (AV nodal block). Stage 3: chronic monoarthritis, migratory polyarthritis. Doxycycline, ceftriaxone
Ehrlichiosis. Pathogen/Transmission. Presentation.
Lone Star tick. Granulocytes with berry cluster organisms. No Rash
Wuchereria bancrofti. Transmission, Presentation, Treatment
Mosquito. Blockage of lymphatic vessels (elephantiasis). 9mo-1y after bite for symptoms. Diethylcarbamazine
Rocky Mountain Spotted Fever. Pathogen, Transmission, Presentation
Dermacentor tick (east coast). Rickettsia rickettsii (obligate intracellular). Classic triad of headache, fever and rash (vasculitis). Starts on palms and soles.
Tularemia. Pathogen, Transmission, Presentation
Francisella tularensis (intracellular Gram negative bacterial rod). Dermacenter tick/deer fly, rabbits.
Plague. Pathogen, Transmission
Yersinia pestis (intracellular Gram negative enterics). Flea bite, rodents, prairie dogs.
What is genetic shift (reassortment)?
Viruses with segmented genoms (e.g. influenza virus) exchange segments. Cause of worldwide influenza pandemics.
What is viral complementation?
When 1 of 2 viruses that infect the same cell has defect. The nonmutated one “complements” the mutated one by making a functional protein that serves both viruses.
What is genetic drift?
Random mutational changes; can change surface of organism affecting host immune response. Changes more gradual than shift (e.g. HIV)
What is viral phenotypic mixing?
2 related viruses infect same cell and capsid produced is a mixture of both parents. Since genomic RNA is not reassorted, progeny has only one coat from parent.
What is phenotypic masking?
2 related viruses infect single cell. Capsid produced is created from genome of other virus, but genome is different.
What are the picoRNAviruses?
PEECoRnA viruses
Polio, Entero, Echo, Coxsachie, Rhino, hep A
What are the positive-sense RNA viruses?
Calicivirus, Hepevirus, Picornavirus, Flavivirus, Togavirus, Coronavirus, Retrovirus
Hand-foot-mouth disease. Agent and presentation
Cosackievirus type A (picornavirus), vesicular rash on palms and soles; ulcers in oral mucosa.
What viruses have double stranded DNA?
Herpesviruses (linear), hepadnavirus (partial circular), adenovirus (linear)
What viruses are single stranded DNA?
Parvovirus (linear), Papillomavirus (circular), Polyomavirus (circular), Poxvirus (linear, largest)
Which viruses are negative-stranded RNA?
Arenaviruses, Bunyaviruses, Paramyxoviruses, Orthoyxoviruses, Filoviruses, Rhabdoviruses
What is floppy-baby syndrome?
Infant botlusim (clostridium botulinum). honey to infants; toxin ingestion from spores, generated in intestine and carried by blood to CNS Flaccid paralysis - blocking ACh release at cholinergic synapses. oxin encoded in genome of temperate phage (lysogeny)
Botulism Toxin. Pathogen, Presentations
Clostridium botulinum (G+, spore-forming, obligate anaerobic bacilli). Produces preformed, heat-labile toxin (bacteriophage) that inhibits ACh release at NMJ, causing botulism. In adult - disease caused by ingestion of preformed toxin. Babies, ingestions of bacterial spores in honey causes disease - reversible floppy baby syndrome)
What is the mechanism of vancomycin resistance?
Vancomycin: inhibits cell wall mucopeptide formation by binding D-ala D-ala portion of cell wall precursors (bacteriocidal). Used for G+
Resistance from enterococci using D-lactic acid instead. (plasmid mediated)
What are some drugs that are susceptible to:
enzymatic (acetylation) deactivation, altered drug-binding protein, beta-lactamase, decreased ribosomal binding, formation o f novel cell-wall peptide?
a. aminoglycosides, chloramphenicol, sulfonamides; b. penicillin; c. penicillins and cephalosporins; d. protein synthesis-inhibiting antibiotics-tetracycline, minocycline, doxycycline, macrolide antibiotics; e. vancomycin
What infection has the classic pseudomembrane on oral and nasal mucosa
Corynebacterium diphtheriae (inhibits eEF-2, inhibiting protein synthesis); extremely contagious; also cause laryngeal palsy and lower limb polyneuritis
