A man now in the intensive care unit at San Francisco General Hospital has the same "very virulent strain" of TB that has stricken seven men since December 2005, according to Dr. Masae Kawamura, director of TB control with the city's Department of Public Health.
Five of the men lived at the same South of Market Street single-room occupancy hotel, which houses about 50 low-income residents.
"We've never seen this drug-resistant strain among the homeless and marginally housed," Kawamura said. "There could be tinderbox effect with exposure in crowded conditions to imported, highly drug-resistant strains." At first, authorities did not link the cases to the hotel.
When doctors diagnosed the first patient in December 2005, they treated him with the standard regimen of four antibiotics, not knowing he was already resistant to three of them. He quickly developed resistance to the fourth drug and to two second-line treatments. The patient is not contagious, but some of his sputum samples meet CDC's criteria for extensively drug-resistant TB (XDR-TB).
After the first case was identified as drug resistant, Kawamura said the other patients diagnosed with the same strain have been treated with more than four antibiotics and have not developed further resistance. One patient had been sick for almost a year before he presented for treatment; he apparently carried the drug-resistant strain from Siberia. One patient died in April 2006, just one month after being diagnosed.
