London ? A new, deadly strain of tuberculosis has killed 52 of 53 people infected in the last year in South Africa, the World Health Organization said Friday, calling for improved measures to treat and diagnose the bacteria.

The strain was discovered in the Kwazulu-Natal region of South Africa, and is classified as extremely drug-resistant.

Drugs from two of the six second-line medicines, used as a last line of defense against TB, proved ineffective against the new strain.

Though even the most drug-resistant strains of TB have proven to be treatable with three classes of drugs, those drugs are more expensive and are toxic to the human body.

The WHO and its partners, including the South African Medical Research Council and the U.S. Centers for Disease Control and Prevention, planned a two-day meeting next week in South Africa to discuss the new TB strain in Africa and better ways to diagnose and treat it, Nunn said.