The extent of the new outbreak is unknown because tests are expensive and specialized. Dr. Tony Moll identified the strain in tests carried out at King George V Hospital in Durban, the provincial capital about 150 miles southeast of Tugela Ferry, where Moll works at a government hospital.
"Most hospitals don't have such facilities and support," Moll said in an interview this week.
Extreme drug resistant TB has been identified among highly mobile miners and probably can be found all over the country, Moll said.
"In some of the mines, they have identified (extremely drug-resistant TB) and, because our population is so mobile, if you looked in other provinces, no doubt you will find" the new strain, he said.
The World Health Organization warned about the new strain Moll discovered at a news conference in London on Friday, and said people could be dying in places that don't have the capacity to find and diagnose patients. WHO classified the strain as extremely drug-resistant, saying drugs from two of the six medicines used as a last line of defense against TB proved ineffective against the new strain.
Drug resistance is a common problem in TB treatment, but the new strain appears particularly virulent. Worldwide, about 2 percent of drug-resistant TB cases are classified as extremely drug-resistant.
Moll found only a few cases in thousands of people tested, but said the strain was "very highly troubling and alarming because of the very high fatality rate."
TB has been on the rise because AIDS has lowered so many South Africans' ability to fight off it and other infections. All 53 patients who had extreme drug-resistant TB tested positive for HIV or were suspected positive, Moll said.
The government estimates more than 5.5 million of the 44 million South Africans are HIV-positive, second only to India. On average, more than 900 people die of the disease a day in South Africa.