Although prescriptions of antibiotics for respiratory tract infections declined during the 1990s, primary care physicians still continue to prescribe antibiotics for a high proportion of infections even if the causes of the symptoms are likely to be viral -- which cannot be treated by antibiotics, according to the study published in a supplement to the Journal of Antimicrobial Chemotherapy.

This practice is hindering efforts to prevent the spread of antibiotic resistance, whereby disease-causing bacteria become unresponsive to the most commonly used drug treatments, according to Dr. Douglas Fleming, a member of the United Kingdom's Specialist Advisory Committee on Antimicrobial Resistance.

The researchers searched for all consultations between 1998 and 2001 for conditions that might have resulted in an antibiotic prescription.

The most common causes of antibacterial prescribing identified in the study were upper respiratory tract infection, lower respiratory tract infection, sore throat, urinary tract infection, otitis media, conjunctivitis, vague skin infections, sinusitis, otitis externa and impetigo.