Antibiotics 1
Name 2 mycobacteria species in which rifampin is bactericidal.
Mycobacterium leprae Mycobacterium kansasii, Mycobacterium scrofulaceum, Mycobacterium intracellulare, and Mycobacterium avium.
Isoniazid is a potent inhibitor of following 2 enzymes.
CYP2C19 and CYP3A
According to past guidelines, name 2 1st line antibiotics against Mycobacteria
Isoniazid, pyrazinamide, rifampin, and ethambutol.
Name 2 subspecies of M. avium.
M. avium subsp. hominissuis (immunocompromised patients), M. avium subsp. paratuberculosis (implicated in the etiology of Crohn disease) and M. avium subsp. avium (TB of birds).
Name and define 2 clinical types of leprosy?
Tuberculoid leprosy or paucibacillary leprosy: bacterial burden is low.
Borderline (dimorphous) tuberculoid disease: it has tuberculoid and lepromatous leprosy.
Indeterminate disease: early hypopigmented lesions without features of the other leprosies.
Lepromatous form: disseminated infection and a high bacillary burden.
What is the most important adverse effect of ethambutol?
Optic neuritis, resulting in decreased visual acuity and loss of red-green discrimination. Recovery usually occurs when ethambutol is withdrawn.
What are the 3 aminoglycosides that can be used in the anti-TB therapy?
Streptomycin, Amikacin, and Kanamycin
According to past guidelines, name 2 2nd line antibiotics against Mycobacteria
ethionamide, PAS, cycloserine, amikacin, kanamycin, and capreomycin.
In the case of newly diagnosed patients. What drugs are used in the treatment regimen?
Triple-drug therapy. Rifamycin (rifampin), ethambutol, and a macrolide (clarithromycin or azithromycin).
Name the 3 most used drugs for the thearpy against leprosy.
Rifampin, clofazimine and dapsone.
What is the MA of Pretomanid?
it inhibits M. tuberculosis mycolic acid and protein synthesis. Also, it generates reactive nitrogen species such as NO via its des-nitro metabolite.
Name 2 possible MAs of clofazimine.
Membrane disruption, inhibition of mycobacterial phospholipase A2, inhibition of microbial K+ transport, generation of hydrogen peroxide, interference with the bacterial electron transport chain, or efflux pump inhibition.
Define the traditional regimen for antituberculosis prohylaxis therapy.
Oral isoniazid, 300 mg daily or twice weekly, for 6 months in adults. Other option: rifampin, 10 mg/kg daily, for 4 months.
In the case of therapy of disseminated M. avium complex. How is the diagnosis made?
Compatible clinical picture, isolation of MAC from cultures of blood, lymph node, bone marrow, or other normally sterile tissue or body fluids.
What is the definitive therapy regimen for paucibacillary leprosy
Single dose of oral rifampin, 600 mg, combined with dapsone, 100 mg (DOT) once every 6 months, and dapsone, 100 mg/d, in between 6 months.
Name 2 therapeutic uses in the treatment of TB for fluoroquinolones.
Examined to attempt to shorten therapy duration in pulmonary TB and for the treatment of TB meningitis (clinical trials). Fluoroquinolones, especially moxifloxacin, continue to be central for the treatment of pulmonary MDR-TB.
What is MA of Ethionamide
Inhibits mycobacterial growth by inhibiting the activity of the inhA gene product, the enoyl-ACP reductase of fatty acid synthase II (impairment of cell wall synthesis).
Define the two phases of the definitive antituberculosis therapy.
Initial phase of therapy: isoniazid (administrate pyridoxine to reduce neurological toxicity), rifampin and pyrazinamide for 2 months.
Continuation phase of therapy: intermittent rifampin and isoniazid two or three times a week for 4 months.
When the MAC prophylactic therapy should be discontinued?
Once the CD4 count is greater than 100 per mm3 for 3 months or longer.
Rifampin is a batericidal agent against mycobacteria and it is not often given during a “reversal” reaction. What is a reversal reaction?
Manifestations of delayed hypersensitivity to antigens of M. leprae.
What is the major concern with bedaquiline in regards with its untoward effects?
Cardiovascular toxicity and death.
What is the main untoward effect of dapsone in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency and what is its main therapeutic use?
Severe hemolysis.
Against leprosy.
How many drugs are required for the therapy of drug-resistant TB and what are their desired characteristics?
At least three drugs to which the pathogen is susceptible, with at least one of the injectable anti-TB agents.
What are the three drugs normally used in the definitive and suppressive therapy?
Name one possible fourth drug that can be added in the case: < 50/mm3, an MAC burden: > 2 log10 CFU/mm3 of blood or in the absence of effective antiretroviral therapy.
Clarithromycin (or azithromycin) with ethambutol. Rifabutin can be added.
Name 2 drugs used as therapy against M. kansassi.
Isoniazid, rifampin, ethambutol, Trimethoprim-sulfamethoxazole; ethionamide; cycloserine; clarithromycin; amikacin; streptomycin; moxifloxacin or gatifloxacin.