What genes are associated with rifampicin resistance?

Background: Rifampicin (RIF) plays a pivotal role in the treatment of tuberculosis due to its bactericidal effects. Because the action of RIF is on rpoB gene encoding RNA polymerase β subunit, 95% of RIF resistant mutations are present in rpoB gene.

What gene might be altered in a rifampin resistant strain?

Resistance to rifampicin (Rifr) arises from mutations in the rpoB gene, which encodes the β subunit of RNAP. These mutations decrease the affinity of RNAP for rifampicin (Xu et al., 2005).

How do bacteria become resistant to rifampicin?

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.

What does the rpoB gene do?

In a bacterium without the proper mutation(s) in rpoB rifampicin binds to a site near the fork in the β subunit and prevents the polymerase from transcribing more than two or three base pairs of any RNA sequence and stopping production of proteins within the cell.

What is rifampicin resistance?

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. [1] MDR-TB/RR-TB is emerging as major problem due to poor management of drug sensitive as well as drug resistance TB.

What is rpoB sequencing?

Sequencing of rpoB enables efficient estimation of bacterial G+C% content, DNA–DNA hybridization value and average nucleotide identity (percentage of the total genomic sequence shared between two strains) when taxonomic relation- ships have been firmly established.

What is inhA mutation?

inhA mutations cause low-level resistance to the drug, which means that high doses of INH may be effective against M. tuberculosis. 6,7. As ETH is a structural analogue of INH, cross-resistance occurs between INH and ETH.

Is E coli resistance to rifampicin?

coli clones exhibited resistance to rifampicin. Twelve of these 13 clones included a mutation in codon 572 of the rpoB gene, with three different mutations observed in that codon (Table 1). These three mutations have been noted previously to confer rifampicin resistance [32], a finding we have reconfirmed.

What is resistance to rifampicin?

Resistance to rifampicin (RIF) is a broad subject covering not just the mechanism of clinical resistance, nearly always due to a genetic change in the β subunit of bacterial RNA polymerase (RNAP), but also how studies of resistant polymerases have helped us understand the structure of the enzyme, the intricacies of the …

Why does rifampicin only inhibit the bacterial enzyme?

Crystal structure data and biochemical data suggest that rifampicin binds to the pocket of the RNA polymerase β subunit within the DNA/RNA channel, but away from the active site. The inhibitor prevents RNA synthesis by physically blocking elongation, and thus preventing synthesis of host bacterial proteins.

What is meant by rifampicin?

Rifampicin, also known as rifampin, is an antibiotic used to treat several types of bacterial infections, including tuberculosis (TB), Mycobacterium avium complex, leprosy, and Legionnaires’ disease.

Does rifampicin resistance depend on mutational sites of the rpoB gene?

Rifampicin resistance and mutation of the rpoB gene in Mycobacterium tuberculosis Using 39 clinical isolates of Mycobacterium strains with a broad range of susceptibility to rifampicin, we examined the relationship between the degree of resistance to rifampicin and mutational sites of the rpoB gene.

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.

What causes rifampicin resistance in Escherichia coli (ESC)?

Resistance to rifampicin (Rif r) arises from mutations in the rpoB gene, which encodes the β subunit of RNAP. These mutations decrease the affinity of RNAP for rifampicin ( Xu et al., 2005 ). In Escherichia coli, the majority of resistance mutations in the RpoB protein are located in three clusters.

Can rifampin-resistant Mycoplasma smegmatis rpoB gene be altered?

Using PCR mutagenesis techniques, we introduced a specific rpoB point mutation (associated with clinical strains of rifampin-resistant M. tuberculosis) into the cloned M. tuberculosis rpoB gene and expressed this altered gene in the LR222 strain of M. smegmatis, which is susceptible to rifampin (MIC = 25 micrograms/ml).