What does resistance to rifampicin mean?

What does resistance to rifampicin mean?

Rifampicin-resistant TB (RR-TB) defined as resistance to rifampicin detected using genotypic or phenotypic methods with or without resistance to other first-line anti-TB drugs. MDR-TB/RR-TB has been an area of growing concern to human health worldwide and posing a threat to the control of TB.

How does rifampicin resistance work?

Bacterial resistance to rifampin is caused by mutations leading to a change in the structure of the beta subunit of RNA polymerase. Such resistance is not an all-or-nothing phenomenon; rather, a large number of RNA polymerases with various degrees of sensitivity to rifampin have been found.

Is Mycobacterium tuberculosis antibiotic resistant?

Like other bacterial pathogens, Mycobacterium tuberculosis—the bacterium that causes TB—has developed resistance to antibiotic treatments over time via chromosomal mutations that protect the organism against the action of the drugs.

Which agent is used for resistant MDR?

Fluoroquinolones are often the most effective anti-TB drugs in an MDR-TB regimen.

How do you test rifampicin resistance?

The Xpert MTB/RIF assay is a new test that is revolutionizing tuberculosis (TB) control by contributing to the rapid diagnosis of TB disease and drug resistance. The test simultaneously detects Mycobacterium tuberculosis complex (MTBC) and resistance to rifampin (RIF) in less than 2 hours.

What is the mechanism of action of rifampicin?

Mechanism of action — Rifampin is thought to inhibit bacterial DNA-dependent RNA polymerase, which appears to occur as a result of drug binding in the polymerase subunit deep within the DNA/RNA channel, facilitating direct blocking of the elongating RNA [3]. This effect is thought to be concentration related [4].

What is MDR treatment?

Treatment of MDR-TB requires treatment with second-line drugs, usually four or more anti-TB drugs for a minimum of 6 months, and possibly extending for 18–24 months if rifampin resistance has been identified in the specific strain of TB with which the patient has been infected.

How is GeneXpert done?

A sputum sample is collected from the patient with suspected TB. The sputum is mixed with the reagent that is provided with the assay, and a cartridge containing this mixture is placed in the GeneXpert machine. All processing from this point on is fully automated.

What is rifampicin resistance (Rr)?

Rifampicin resistance (RR): This is when rifampicin, alone or with other drugs (whether with mono -resistance, MDR, polydrug resistance or XDR), fails to work against TB infection. What is multidrug-resistant TB (MDR-TB)?

Is Mycobacterium tuberculosis resistant to rifampicin?

Mycobacterium tuberculosisisolates cultured from 6 patients associated with an isoniazid-resistant M. tubercu- losis outbreak acquired rifampicin resistance. The rpoB. gene sequence showed that resistance was associated with rare mutations in each isolate.

Why is rifampicin resistance considered as a surrogate marker for MDR-TB?

This is the reason why rifampicin resistance is considered as a surrogate marker for MDR-TB [19]. Recent genome sequencing studies have uncovered the acquisition of compensatory mutations in rpoAand rpoC, encoding the α and β’ subunits of RNA polymerase, in rifampicin-resistant strains with mutations in rpoB[20].

Is cross-resistance between rifamycin and rifapentine different?

Cross-resistance among rifamycins has been a topic of controversy; current thinking is that there is no difference in the susceptibility of RNAP mutants to RIF, rifapentine and rifabutin. Also summarized are intrinsic RIF resistance and other resistance mechanisms.