Abuse of antibiotics by doctors is highlighted again after study of salmonella cases not responding to standard treatment A microbiologist has reinforced warnings against the abuse of antibiotics by doctors and veterinarians, citing a study showing resistance to a drug that was used to treat a potentially fatal bacteria had leapt dramatically over 11 years. The Chinese University study found fluoroquinolone-resistant salmonella bacteria soared from less than 1 per cent of cases at Prince of Wales Hospital in 1990 to nearly 10 per cent in 2001. Julia Ling Mei-lun, who carried out the study in 2002, said she believed the situation overseas was similar, though she did not have figures. Professor Ling refused to comment directly on the use of antibiotics among local doctors, but called on doctors and veterinarians to prescribe them 'very judiciously', and 'not to prescribe if they don't need to do so'. 'Patients also should not ask their doctors to prescribe antibiotics because doctors are the best judges to determine whether antibiotics should be prescribed,' she said. 'Patients should also fully comply with doctors' instructions to complete the course of antibiotics they have been prescribed.' Salmonella bacteria are the most common food-born pathogens in the city, especially among infants. The bacteria causes enteric fever and gastroenteritis, with a mortality rate of up to 30 per cent for the former. Of more than 3,000 patients with bacterial diarrhoea treated at Prince of Wales Hospital between 1994 and 2001, and in other New Territories East cluster hospitals in 2002 and 2003, 60 per cent of the cases were caused by salmonella bacteria. Professor Ling warned that doctors would be deprived of the choice of using fluoroquinolones to treat salmonella if the bacteria built up an immunity to the antibiotic. Fluoroquinolones have been used to treat salmonella infections for about 20 years. Professor Ling said resistance to antibiotics was a serious medical problem faced by doctors worldwide. She warned feeding antibiotics to livestock could affect humans because people may be infected after eating meat contaminated with antibiotic-resistant bacteria. The South China Morning Post has reported that the use of antibiotics will be scrutinised under a Hospital Authority programme to combat the emergence of drug-resistant bacteria. The programme, to begin by the end of this year, will cover 12 drugs. The authority will also set up a centralised database on drug-resistance levels of four common bacteria: escherichia coli, pneumococcus, pseudomonas aeruginosa and staphylococcus aureus. The misuse of antibiotics can lead to the emergence of drug-resistant bacteria such as methicillin-resistant staphylococcus aureus (MRSA) or vancomycin-resistant enterococci. These are difficult to treat and can cause life-threatening infections.