Lecture 52: Multi-Drug Resistant Tuberculosis

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To date, _________ countries worldwide have reported at least one XDR-TB case.

No

have most pts with MDR-TB have had a previous TB infection?

Drug-Resistant Tuberculosis

-any isolate that is resistent to one of the first-line TB drugs

Multidrug-Resistant Tuberculosis

-isolate resistant to at least Isoniazid and Rifampin

Extremely Drug-Resistant Tuberculosis (XDR-TB)

isolate resistant to at least isoniazid, rifampin, and fluoroquinolone + aminoglycoside or capreomycin or both

Totally Drug-Resistant Tuberculosis (TDR-TB)

isolate resistant to all first and second line TB drugs

• R - Rifampin (RIF)

• I - Isoniazid (INH)

• P - Pyrazinamide (PZA)

• E - Ethambutol (EMB)

first line agents against TB

-Spontaneous chromosomal mutations at a predictable low frequency.

-poor adherence bc of difficult regimens

-Monotherapy or improper drug prescriptions

-drug supply runs out or is of poor quality

how does TB drug resistance occur?

Drug-resistant TB

can occur when the drugs used to treat TB are misused or mismanaged.

Multi-Drug Resistant Tuberculosis (MDR-TB)

At risk:

• Previously treated for TB, esp if tx was inadequate or inappropriate

• When drug supply runs out or is of poor quality

• Pts infected in countries w/ high rates of resistance

• Adherent pts who are not responding to standard empiric therapy

• Close contacts of drug-resistant TB

• Drug susceptibility screening at start of Tx

• Check for resistance on those failing to improve on appropriate regimen

• Rescreen pts failing drug regimens for HIV+

what should you do for Multi-Drug Resistant TB (MDR-TB)?

Russian, Eastern Europe, China and

India

XDR-TB has its highest prevalence where?

Extremely Drug-Resistant Tuberculosis (XDR-TB)

-more associated with HIV+ status

• HIV-infected patients are more likely to have problems with malabsorption, altered drug metabolism, or drug interactions due to concomitant ART.

• This can lead to acquired drug resistance because of inadequate anti-tuberculosis drug levels and increased selection for mutations.

Xpert Ultra

technology that could replace conventional culture as primary TB diagnostic tool