Principles of antimicrobial use

Principles of antimicrobial use

This chapter outlines acceptable approaches to the use of antimicrobials, both in hospital practice and in the community. General principles are outlined in Box 2.1 and summarised in the antibiotic creed.

In hospitals, drug choice may be influenced by such local factors as trends in susceptibility of current isolates, cost of the drugs, and in some instances traditional preference or familiarity. Each hospital’s drug and therapeutics committee should produce its own antimicrobial policies, within the overall framework suggested by these guidelines. Resistance to antimicrobials is common in hospitals and, increasingly, in the community, due to the selective pressure exerted by high drug levels in the biosphere, together with facilitated transfer of organisms between staff and patients. Restraint in prescribing and adherence to the principles discussed in this chapter are equally necessary in both settings.

Principles of use of antibiotics (Box 2.1)

General Use antibiotics only where the benefits are scientifically demonstrable and substantial. In general, use the narrowest spectrum antimicrobial to treat the known or likely pathogen(s). Use single drugs unless it has been proven that combination therapy is required to ensure efficacy or reduce the selection of clinically significant resistance. Use a dose that is high enough to ensure efficacy and minimise the risk of resistance selection, and low enough to minimise risk of dose-related toxicity. Therapy Base choice of therapy on either culture and susceptibility test results (directed therapy), or known common pathogens in the condition and their current resistance patterns (empirical therapy). Duration should be as short as possible, and should not exceed 7 days unless there is proof that this duration is inadequate. Prophylaxis Base choice of antimicrobial on known or likely target pathogen(s). Duration should be as short as possible. A single dose of antibiotic is recommended for surgical prophylaxis. Administer longer-term prophylaxis only when it has been demonstrated that the benefits outweigh the risk of resistance selection or propagation.

Modified from: The use of antibiotics in food-producing animals: antibiotic-resistant bacteria in animals and humans. Report of the Joint Expert Advisory Committee on Antibiotic Resistance (JETACAR). Canberra: Commonwealth Department of Health and Aged Care and Commonwealth Department of Agriculture, Fisheries and Forestry; 1999.

The antibiotic creed (Box 2.2)

M	microbiology guides therapy wherever possible
I	indications should be evidence-based
N	narrowest spectrum required
D	dosage appropriate to the site and type of infection
M	minimise duration of therapy
E	ensure monotherapy in most situations