The discovery of antimicrobials is one of the great advances in medicine, and their use has substantially reduced morbidity and mortality worldwide. Unfortunately, with widespread antibiotic use, we have witnessed the emergence of multidrug-resistant pathogens and reduced efficacy of many of our most powerful antimicrobials. In addition, we have also recognized many adverse effects of antimicrobials, most notably the rising rates of Clostridioides difficile colitis. Further, the cost of medical care is greatly increased due to overuse of antibiotics and treating infections caused by resistant organisms. It is critical that health professionals understand the key concepts behind antimicrobial stewardship at the time they learn about microbial pathogens and antimicrobials.
The worldwide problem of antibiotic resistance makes the need for antimicrobial stewardship evident. The Centers for Disease Control and Prevention estimates that in the United States over 2.8 million infections with multidrug-resistant pathogens occur each year, leading to more than 35,000 deaths. These pathogens include methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum β-lactamase–producing gram negative rods (e.g., Escherichia coli and Klebsiella pneumoniae). Hospital-associated infections, many of which are caused by antibiotic-resistant bacteria, are estimated to cost billions of dollars each year.
The basic principles of good stewardship are threefold: (1) reduce inappropriate use of antibiotics, (2) encourage targeted treatment with narrow-spectrum drugs, and (3) limit adverse effects (Table 1). Inappropriate antibiotic use occurs for many reasons, including provider’s desire to adhere to a patient’s wishes, even when it is not medically appropriate. The most common example of inappropriate antibiotic use is the prescribing of antibiotics for a viral respiratory tract infection. It is esti mated that half of all prescriptions given for upper respiratory infections (pharyngitis, sinusitis) are inappropriate. Inadequate microbiologic information plays a role as well.
Table1. Basic Principles of Antimicrobial Drug Stewardship
The concept of targeted treatment refers to making a micro biologic diagnosis promptly and using the most specific anti biotic that has the best safety profile for the patient. If multiple broad-spectrum antibiotics must be used as empiric therapy early in infection, switching to a narrow-spectrum antibiotic as soon as possible should be done. Cultures should be sent prior to starting antibiotics so that the drugs will not reduce the likelihood of isolating the causative organism. Further, switching from intravenous antibiotics to oral dosing reduces the risk of catheter-associated infections. The net result of targeted treatment is to reduce the ability of antibiotics to select resistant mutants present in the bacterial population.
Limiting the occurrence of adverse effects caused by antibiotics is another major goal of antimicrobial stewardship. Minimizing the duration of antibiotic use to only as long as clinically indicated is a key intervention since duration of exposure closely correlates with the risk of many types of adverse effects. Patients with reduced renal function should have the dose of some antibiotics adjusted based on their estimated glomerular filtration rate.
Antibiotic allergies should be identified and explored in detail. Although reactions to antibiotics may be commonly reported, they may not always be of significance such as some alleged hypersensitivity reactions. If optimal treatment requires a drug such as penicillin to which the patient says he or she is allergic, then skin testing can be employed to confirm or refute the claim. In addition, patients should be counseled that certain drugs may cause adverse effects. For example, certain photosensitizing antibiotics may cause a rash when the patient is exposed to sunlight.
In summary, antimicrobial stewardship refers to the effort to improve the treatment of infectious diseases by the appropriate use of antibiotics. This is critical in this era of rising rates of multidrug-resistant pathogens. Targeted therapy with the most appropriate single antibiotic will hopefully improve clinical outcomes and reduce the cost of care.
