Japan has confirmed its first case of a genetic mutation of the new H1N1 influenza that shows resistance to antiviral drug Tamiflu, Reuters quoted a health ministry official said as saying today. Takeshi Enami, an official at the health ministry, said that the patient's sensitivity to Tamiflu had yet to be tested. The patient, who was confirmed in May with the H1N1 strain of the flu in the Osaka prefecture of western Japan, has recovered since then and that no cases of the new flu have been confirmed around the patient, Enami said. He could not confirm the age or the sex of the patient.