Health authorities are investigating two cases of patients being infected with the drug-resistant superbug MRSA. Although the potentially fatal bug, methicillin-resistant Staphylococcus aureus, is usually found in a hospital setting, neither patient had been admitted to hospital in the past year. The government said last night that the patients, a 31-year-old man from Central and a 28-year-old woman from Eastern District, were in stable condition in Queen Mary Hospital. Both have superficial abscesses on their legs. They were admitted on June 14 and 17. The cases brought a renewed warning against the misuse of antibiotics, which can lead to drug-resistant mutations called superbugs. The Centre for Health Protection and Hospital Authority are investigating the origins of these two infections. The patients' home contacts had no symptoms of infection, the government said. A special study is being conducted on family members to see whether they are carrying MRSA. The superbug is difficult to kill and could be fatal, especially in hospital settings where patients have weakened immune systems. The bacteria, common throughout the world, are almost always spread by direct physical contact, not through the air. 'It is widely recognised that indiscriminate use of antibiotics may contribute to antibiotics resistance,' a Health Department spokesman said. 'If people are advised by doctors to take antibiotics, they should take the medicine according to the prescribed frequency and dosage and complete the course.' The risk of transmission can be minimised by maintaining good personal hygiene, including washing hands with soap frequently and wearing gloves when touching soiled items. Cuts should be kept clean and covered with a proper dressing until healed. Contact with others' wounds should be avoided. Authorities could not provide a figure for the number of MRSA cases in Hong Kong in the past.