Extreme drug resistant tuberculosis (XDR-TB)
Although about 1.7 million people die from tuberculosis globally each year, a “virtually untreatable” form of TB has now emerged, according to the World Health Organization (WHO). Extreme drug resistant TB, XDR-TB, has been seen worldwide, including the US, Eastern Europe and Africa. WHO tuberculosis experts have convened in Johannesburg, South Africa, to discuss how to address the problem. Multi-drug resistant TB or MDR TB, is due to strains of Mycobacterium tuberculosis which are resistant to at least two of the main first-line TB drugs, is already a growing concern. XDR-TB is defined as strains which are resistant to all the current the front-line drugs, but also three or more of the six classes of second-line drugs. In a few rare cases, a strain resistant to all currently available drugs have been seen. A recent survey of 18,000 TB samples by CDC and the WHO between November 2004 and November 2005 found 20% of them were multi-drug resistant and a further 2% were extreme drug resistant. In the US, 4% of all MDR TB cases met the criteria for XDR-TB; in South Korea, the figure was 15%. In eastern Europe, 19% of all multi-drug resistant cases were extreme drug resistant too.
Current concerns centre on South Africa, where in Kwazulu-Natal, 53 patients have been found with XDR-TB. Of these, 52 died within 25 days, and 44 were also found to be HIV positive. XDR-TB could have a bigger impact on developing nations, especially in Africa, because of the prevalence of HIV.
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I’ve been interested in MDR bacteria since i started my university studies 2 yrs ago. From my understanding MDR bacteria is a good example of ‘micro’ evolution, such as XDR TB or more famously MRSA and VRSA. Of course MDR is of huge concern for future treatment (even though there other avialable lines of treatment, antibiotics is the most powerful – from my knowledge). However, antibiotics are changing because they are biological products, produced by a living organism subjected to the laws of evolution. Therefore would it not be possible to place the bactera that produces Methicillin on a medium with the likes of MRSA? If evolution is anything to go by, some bacteria should mutate to produce an antibiotic that MRSA is vunrable to. Isolating this new antibiotic and biosynthesising it should prove useful in not only treatment of any further MRSA cases, but also in the understanding of the kinetics involved in antiobiotic production and action.
Does my logic make any sense?
Thanks
Methicillin is not produced by bacteria. It is a semi-synthetic compound manufactured by chemically modifiying penicillin so that the resulting chemical cannot be broken down by beta-lactamase (http://en.wikipedia.org/wiki/Methicillin). Hope that helps.
The existence of XDR TB in HIV positive patients may aggravate things such as hadeling of the disease itself and the outcomes of ART in HIV infected people. Therefore, urgent strategies required to at least stop the expansion of XDRTB especially in the newly infected individuals. Moreover, different studies needs to be done in different parts of Africa where illegal and extensive use of major anitbiotics is there.
With regards,
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BCG LOOKS BETTER AND BETTER, DOESN’T IT?
IF THE PREDICTIONS ARE TRUE WE SHOULD BE USING THIS VACCINE TO P R E V E N T TB. THIS IS THE PATH THE CDC AND THE WHO SHOULD BE ON. 1/3 OF THE WORLD POPULATION AFFECTED, THERE IS NO OTHER WAY TO ATTACK THIS.
(BCG IS THE ATENUATED BACILLUS USED TO CREATE AN IMMUNE RESPONSE TO TB AND PREVENT THE SPREAD OF THIS DISEASE)