We describe a test which uses the ability of viable cells to reduce 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) to detect resistance to a bactericidal drug, rifampin, in in vitro-cultured Mycobacterium tuberculosis. The assay shows a linear relationship between the number of viable bacteria and the ability to reduce MTT. Dead mycobacteria were unable to reduce MTT. Rifam...

Resistance of frog virus multiplication to rifampin suggests that components peculiar to cytoplasmic deoxyribonucleic acid replicating viruses (e.g., poxvirus) are not equally sensitive to rifampin.

Although all of 14 clinical isolates of Haemophilus influenzae type b strains demonstrated rifampin susceptibility in vitro (minimal inhibitory concentration less than or equal to 0.4 microgram/ml) when an inoculum of 10(4) colony-forming units (CFU) was used, 10 of the 14 strains manifested resistance to this agent when an inoculum of 10(8) CFU was tested. The mutation rate for rifampin resist...

Current clinical assays for determining antibiotic susceptibility in Mycobacterium tuberculosis require many weeks to complete due to the slow growth of the bacilli. Here we demonstrate an extremely sensitive single-tube PCR assay that takes less than 3 h and reliably identifies rifampin-resistant M. tuberculosis in DNA extracted directly from sputum. Ninety-five percent of mutations associated...

Intensive use of antimicrobial agents in health care settings not only leads to the selection of multiresistant nosocomial isolates of Staphylococcus aureus but may also promote endogenous, resistance-conferring mutations in bacterial genes that encode drug targets. We evaluated the spectrum of rifampin resistance-conferring mutations in cultures of methicillin-susceptible S. aureus (MSSA) or m...

The increasing incidence of Multi Drug Resistance Tuberculosis (MDR-TB) and Extensively Drug Resistance TB (XDR-TB) worldwide highlight the urgent need to search for newer anti-tuberculosis compounds. It has been determined that pharmaceutical plant, hops (Humulus lupulus), possesses some antibacterial effect. In this study, the antimycobacterial effect of this plant on rifampin sensitive and r...

Background and Objectives: The incidence of rifampin-resistant strains of Mycobacterium tuberculosis has attracted more attention than the tuberculosis infection due to laborious treatment and control. Recognizing the Mycobacterium tuberculosis genotypes involving in drug resistance via multiplex PCR, a simple and rapid genotyping method, is an emergency for better tre...

Activity of rifampin against 129 Streptococcus mitis isolates obtained from patients with hematologic cancer was investigated. One hundred twenty-five strains were susceptible to rifampin, and 4 were resistant (MIC = 32 to 64 microg/ml). Resistance to rifampin was related to mutations in the rpoB gene: His(526)Asn in three strains and His(526)Asp in one strain.

We assessed the performance of a rapid, single-well, real-time PCR assay for the detection of rifampin-resistant Mycobacterium tuberculosis by using clinical isolates from north India and Mexico, regions with a high incidence of tuberculosis. The assay uses five differently colored molecular beacons to determine if a short region of the M. tuberculosis rpoB gene contains mutations that predict ...

Drug-resistant tuberculosis is a public health concern. TB that drug-resistant to rifampin and isoniazid known as MDR-TB, whereas XDR-TB MDR-TB also resistant second-line medicines, such fluoroquinolones (levofloxacin, ofloxacin, moxifloxacin). rifampin-resistant (RR-TB), of which 78 percent had multidrug-resistant (MDR-TB) (MDR-TB). Fluoroquinolones are class broad-spectrum antimicrobials have...