A Bronx doctor who began performing oral sex on a patient while examining his genitals, pleaded guilty Thursday to sexual misconduct, prosecutors said. As part of a plea agreement, Brian Shaw, 42, of Wilton, Conn., will be sentenced to six years probation and is required to register as a sex offender, said Bronx District Attorney Robert Johnson. Sentencing was set for Feb. 2, 2005. The patient, a 49-year-old truck driver, had gone to the Throgs Neck Urgent Medical Care facility on Dec. 9, 2003, because of a rash on his chest.