Drug-resistant tuberculosis is on the increase, with highest-ever rates being reported around the world, according to a report published by the World Health Organization.

"TB drug resistance needs a frontal assault," said Dr. Mario Raviglione, director of the WHO's Stop TB Department, in a release. "If countries fail to address it aggressively now we will lose this battle."

The report, released Tuesday, is based on data from 81 countries and 90,000 TB patients, and was collected between 2002 and 2006.

Forty-five of those countries were found to have extensively drug-resistant TB, which is a form of tuberculosis that is almost completely untreatable.

The WHO estimates that there are nearly half a million new cases of multi drug-resistant TB a year worldwide — which account for five per cent of nine million new TB cases of all varieties.

Baku, the capital of Azerbaijian, has the highest rate of multi drug-resistant TB, accounting for 22.3 per cent of all TB cases.

Canada has experienced low levels of drug-resistant TB and relatively steady trends in resistance among both new and previously-treated cases of TB, according to the report. In 2005, 23 multi drug-resistant TB cases were identified, the study finds.

The study also found a correlation between HIV and multi drug-resistant TB, with HIV patients in Latvia and the Ukraine having nearly twice the level of drug-resistant TB as those without HIV.

The WHO believes that approximately $4.8 billion US is required to control TB in low and middle-income countries in 2008, with $1 billion of that money going to combating multi drug-resistant TB.