Implications for antimicrobial prescribing of strategies based on bacterial eradication.

Antimicrobial prescribing in respiratory tract infection is generally empirical. Agents that do not eradicate the key bacterial respiratory pathogens (Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis) provide suboptimal therapy. A recent paper developed by a multidisciplinary, multinational group presented a consensus on the principles that should underpin appropriate antimicrobial prescribing. In summary, in order to ensure clinical success and minimize the threat of resistance, empirical therapy should avoid unnecessary and inappropriate use of antimicrobials, deliver the right agent at the right dose and duration, and rapidly eradicate the pathogen at the site of infection. Accurate diagnosis is essential to ensure that only bacterial infections are treated with antibacterial agents. The application of pharmacokinetic/pharmacodynamic (PK/PD) principles to both new and existing antimicrobials allows the prediction of bacteriologic efficacy. Applying these principles when prescribing therapy can help in reducing the potential for the selection and spread of resistance. Local resistance patterns and the bacteriologic/clinical impact of resistance should also be considered. The use of antimicrobials with optimal PK/PD characteristics may be more cost-effective than allowing the possibility of resistance-induced failure. Changing prescribing habits without taking all these factors into account may increase the incidence of unfavorable patient outcomes and the cost of treatment, with more referrals and hospitalizations. Changes in prescribing habits should be considered carefully, to avoid unintended negative consequences. It is the responsibility of physicians to ensure that each prescription is necessary and will maximize the potential for clinical cure, but there is also a collective responsibility to sustain the diversity of antimicrobial therapy via appropriate formularies, guidelines and licensing, reduced over-the-counter availability, and continued research and development through academia and industry. To maximize clinical cure and minimize the emergence and spread of resistance, antimicrobial prescribing should maximize bacterial eradication, and clinical drug evaluation needs to be brought into line with this need.