HONG KONG, July 26 (Reuters) - A Taiwanese man suffering from a drug-resistant form of tuberculosis took two flights to reach China last week, prompting a hunt for passengers who travelled with him, officials said. The 55-year-old man, breaking a travel ban, flew out of Kaohsiung in Taiwan on Dragonair flight KA 435 to Hong Kong on July 21, accompanied by his wife, who is also suffering from TB. The couple then took Dragonair flight KA 810 to Nanjing in eastern China, according to a statement from Taiwan's Centers for Disease Control. The couple's flight comes after a U.S. lawyer set off international alarms in May for fleeing across borders when he was thought to be infected with the most dangerous form of TB, or extensively drug-resistant TB, which is extremely difficult to treat. The U.S. man has since been confirmed with multidrug-resistant TB (MDR-TB), which is less dangerous but still difficult to cure. The Taiwan man, who was not identified, also has MDR-TB, which is resistant to two major drugs, the disease control center said. There are second-line drugs that can treat this form of TB. His 57-year-old wife suffers from standard TB, which is more treatable, but she is deemed to be infectious. More than 270 people were on the first flight and over 120 were on the second, but authorities were looking for those who sat in the same row as the couple and those who sat in the two rows in front and behind them. "They will be sent for checks and if they display symptoms, they will be given medication," said a spokeswoman for Hong Kong's Health Department, adding that Taiwan was also trying to track down passengers. TB is a highly infectious disease that is spread by coughing and sneezing, and kills about 1.6 million people a year. One of of every three people in the world is infected with dormant TB bacteria but it is only when a person's immunity is low that the TB bacteria becomes active and symptoms show. The Taiwanese disease control center said the couple were staying with relatives in Nanjing, and Taipei had dispatched a medical officer to help them obtain treatment in China and arrange their journey home. Taiwan prohibits people with MDR-TB from any air travel and those who flout the rules can be fined T$150,000 (US$4,570).