5-2 Bacteriology

q123456's version from 2016-05-30 15:09


Question Answer
Generalized transduction
Hfr to F- conjugation
Specialized transduction

Anti TB

Question Answer
Ant TBisonazid: inhibition of mycolic acid synthesis, it must be processed by mycobacterial catalase-peroxidase for the durg to be activated within the bacteria.

mycobacterial resistance to isoniazid
decreased activity of intracellular catalase peroxidase, modificaiton of the protein target binding site for isoniazide. mst use comining multiple antibiotics to avoid resistance

isolates of M tuberculosis growing in culture lose acid fastness and rapidly stop proliferating when expose to Drug _____? Isonazid

rifampin: p450 inducer 1) Mycobacteral infection 2) leprosy 3) prophylactic monotheary when exposed to H influenzae or N meningitidis. SE: red uring and red stining of the contact lenses
p450 inducer

visual changes, inhibition of carbohydrate polyerizaiton which is necessary for mycobacterial cell wall synthesis, inhibiting arabinosyl transferase>>>inhibit polymerizes arabinose into arabinan and then arabinogalactan

acidic pH, in phagolysosomes, for M tuberculosis engulfed by macrophages. isonazid, rifampin and ethambtol for extracellular MTB

isoniazide, rifampin and pyrazinamide:hepatic functionisonazid:synthesis of mycolic acids
rifampin: inhibits DNA-dept RNA polymerase
ethambutol:carbohydrate polymerization of cell wall
pyrazinaide: acidic pH of pahgolysosomes
an elderly immigrant complain numbness and tingling of his hand and feet. he was diagnosed with pulmonary tuberculosis vitamin deficiency (vitamin B6)
mycobacterium avium complex MAC in patients with HIVWhen CD4 counts fall to less than 50 cells/mm3, CD4 counts normal: TB KA33-32
acid fast bacteria grow at 41 C,
Hepatosplenomegaly and retroperitoneal lymphadenopathy.
long branched satrated fatty acids mycolic acids
Miliary tuberculosisKA35-30


Question Answer
the basic principles of antibioticstetracyclines:COMPETITION with tRNA for the A site
gentamicin/neomycin/strptomycin: abnormal codon:anticodon (MISREADING)
linezolid: blocks INITIATION complex formation
chloramphenicol: inhibition of TRANSPEPTIDATION
puromycin: RESEMBLES the amino acid end of tRNA
erythromycin: inhibition of TRANSLOCATION
quinolones(xacin): DNA gyrase
rifamycin: bacterial RNA polymerase
resistance of antibioticserythromycin: methylation of 23S rRNA binding site,
chloramphenicol: plasmid encoded acetyltransferase that inactivates drug,
sulfonamides: mutation of dihydropteroate synthetase,
fluoroquinolones: chromosome encoded mutation in DNA gyrase,
vancomycin: D-ala D-ala to D-ala D-lac,
gentamicin: enzymes transfer acetyl groups to antiboitic molecule>>>decreasing the ability of the drugs to bind to ribosomes, tetracyclines: decrease uptake into cells/increase efflux out of cells by plasma-encoded transport pumps
tazobactam+piperacillindecreasing destruction of piperacillin
gram+, gram- and anaerobic bacteria
metronidazoleused to treat trichomonas vaginitis and bacterial vaginosis

metronidazole: female facial flushing, headach, naucea vomiting and abdominal cramps after havign an alcoholic drink
interaction with alcohol>>>inhibition of alcohol oxidizing enzymes>>>acetaldehyde accumuation
a 2 month old boy is brought to the ER with fever, irritability and vomiting, lumbar puncture reveals CSF pleocytosis and you proceed with empirical ceftriaxone therapy. you must also administer ampicillin to cover for which of the following bacteria?listeria monocytogenes (facultative intracellular organnism)
trimethoprim, methotrexate and pyrimethaminefolic acid>>>tetrahydrofolate
inhibiting dihydrofolate reductase
sulfamethoxazole, sulfisoxazole and sulfadiazinedihydropteroate synthetase
AntimetabolitesFolic acid antagonist: Methotrexate.
Pyrimidine antagonist: 5-Fluorouracil, Foxuridine, Cytarabine, Capecitabine, and Gemcitabine.
Purine antagonist: 6-Mercaptopurine and 6-Thioguanine.
Adenosine deaminase inhibitor: Cladribine, Fludarabine and Pentostatin.
SE of antibioticsaminoglycoside: renal function, hearing and vestibular function
chloramphenoicol:need to check complete blood count
most commonly used to treat infections caused by penicillinase producing strains of S aureus?penicillinase resistant penicillins(nafcillin, methicillin and oxacillin)>>>skin and soft tissue infections
Which tetracycline is safest to a CKD patientsdoxycycline KA26-4


Question Answer
first generation of cephalosporinescepha, cefazolin
second generation of cephalosporinescef-a/o/u/m/p, loracarbef
Third generation of cephalosporinescefo(long), cef, moxalactam
ceftriaxone resistance1) production of a beta lactamase>>>prevent ceftriaxone from being able to bind to the penicillin binding proteins.
2) structral changes in penicllin binding protein (transpeptidases)

Anti fugus

Question Answer
amphotericin BSystemic, Binds ergosterols, alters permeability; pore formation
ALL life-threatening mycotic infections
nystatinTopical; mucocutaneous fungal infections; mostly candida
flucytosineConvert to 5-FU, Pyrimidine analog
itraconazoleBlocks fungal P450
interferes with ergosterol synthesis
caspofungininvasie aspergillosis
Blocks b-glucan synhtase>>>Prevents cell wall synthesis
Inhibits epoxidation of squalene in fungi ergosterol
Minor GI effects, hepatotoxicity
Interferes with microbubule function
anti fungus SEamphotericin B: nephrotoxicity
azoles: p450 inhibitor
flucytosine: bone marrow suppression
caspufungin: GI upset
griseofulvin: p450 inducer


Question Answer
protease inhibitors for HIV"navir“
RT: RNA dependent DNA polymerase
completely inhibit nucleotide binding to RT and terminate the DNA chain.
must be phosphorylated by thymidine kinase to be active
NNRTIs "VIR"nevirapine
binds to RT at site different form NRTIs
Do not require phosphorylation to be active or compete with nucleotides
synergistic if use in combination with NRTIs and/or PIs
antiretroviral drugs-indinavirlipodystrophy, hyperglycemia and inhibition of p 450
zidovudine's SEAnemia
anti HIVenfuvirtide (gp 41 not gp120, fusion inhibitors)

navir(protease inhibitors)

efavirenz, tenofovir, vudine(RT inhibitors)

raltegravir (integrase inhibitors): double stranded viral DNA enters the host cells nucleus and insert into the host choromosomes by integrase.

maraviroc (CCR5 receptor inhibitors)