Drug Resistance Mechanisms in Mycobacterium tuberculosis
18. Park IN, Hong SB, Oh YM, et al. Efficacy and tolerability of daily-half dose linezolid in patients with intractable multidrug-resistant tuberculosis. ;58:-
Drug-Resistant Gonorrhea Cases Up Fourfold in U.S. - WebMD
The team concluded that the chemical compounds could be used alongside existing antibiotics to combat strains of TB which have developed resistance to anti-bacterial drugs.
The failure of short-course chemotherapy against MDR tuberculosis, though unsurprising clinically, was difficult politically. In Peru, for example, a campaign to promote the DOTS strategy had been so successful in making short-course chemotherapy available that the country's leaders elevated it as a point of national pride. Peru emerged as a crucible for debates about the treatment and management of MDR tuberculosis in poor countries. In 1995, an outbreak in a shantytown in the northern reaches of Lima was identified. Many patients were infected with strains found to have broad-spectrum resistance to first-line drugs. Nongovernmental organizations worked with the Peruvian Health Ministry to apply the standard-of-care treatment used in New York City and elsewhere in the United States. The strategy was modified to provide community-based care, with good results. After arguing that the DOTS strategy alone could rein in the mutant bacteria, the WHO and other international public health authorities advised the Peruvian government to adopt a low-cost, standardized regimen for the treatment of MDR tuberculosis rather than protocols based on the results of drug-susceptibility testing. In the absence of tailored therapy, many hundreds of deaths occurred among some of Lima's poorest people. As expected, amplification of drug resistance was documented.
Report warns of rise in drug-resistant tuberculosis | …
Xpert MTB/RIF, a cartridge-based point-of-care assay, is designed to identify rifampin resistance mutations in an 81-bp region of (codons 426 to 452). Its inability to detect the I491F outbreak strain raises new challenges, since Xpert MTB/RIF is used throughout most of Swaziland as the first-line diagnostic test for tuberculosis and for multidrug-resistant tuberculosis, as recommended by the WHO. Thus, the circulation of strains with the I491F mutation substantially reduces the sensitivity of Xpert MTB/RIF–based diagnosis in Swaziland and presumably results in underdiagnosis and potentially inadequate treatment. This is problematic in a country where an estimated 26% of adults are infected with the human immunodeficiency virus (HIV) and 80% of patients with tuberculosis are coinfected with HIV. In addition, coinfected patients are more likely than HIV-negative patients to have multidrug-resistant infection. Further transmission of the I491F strain in this population is another likely consequence.
Report warns of rise in drug-resistant tuberculosis
In an outbreak of tuberculosis, a strain of isolated from the source case, before the administration of any chemotherapy, was highly resistant to isoniazid, streptomycin and para-aminosalicylic acid. All 23 members of the immediate household were found to be positive tuberculin reactors, and in six of them active tuberculous disease developed. Evidence of spread of this infection into the local community was indicated by a significant increase in the rate of tuberculin reactors among the non-household contacts of the source case.
drug resistant tb | Tuberculosis | Microbiology
On the basis of these findings, Xpert MTB/RIF testing may be unreliable in Swaziland, since it can miss a substantial percentage of strains that may be resistant to rifampin. More studies are needed to assess the prevalence of similar mutations in neighboring countries.