Antibiotic Stewardship: Revisit the Antibiogram to Improve Resident Care

In the Core Elements of Antibiotic Stewardship for Nursing Homes, the Centers for Disease Control and Prevention (CDC) identifies the referral (i.e., consultant) laboratory as a key partner for providing reports and services, including antibiograms, to support antibiotic stewardship. However, an annual antibiogram remains an underused tool in nursing homes. The infection preventionist (IP) can take the following steps to work with the lab and other partners to benefit antibiotic stewardship—and ultimately improve the quality of care that residents receive and the quality of life that they experience:

1. Make sure leadership understands why an antibiogram is crucial 

The following information compiled from Agency for Healthcare Research and Quality (AHRQ) sources (here, here, and here) explains what an antibiogram offers:

“Essentially, the antibiogram shows what most of the germs in your particular care community are susceptible to—what antibiotics are most likely to work,” explains Deb Patterson Burdsall, PhD, RN-BC, CIC, FAPIC, an infection prevention and control consultant and board member at the Association for Professionals in Infection Control and Epidemiology (APIC) in Arlington, VA. “For example, if you have enough urinary tract infection (UTI) cultures, your customized annual antibiogram can show the most likely organisms that are causing UTIs in your nursing home.”

Deb Patterson Burdsall, PhD, RN-BC, CIC, FAPIC, infection prevention and control consultant and board member at the Association for Professionals in Infection Control and Epidemiology

The case for developing a facility-specific antibiogram hinges on the fact that its benefits go beyond helping prescribers use antibiotics responsibly for “the greater good” benefit of slowing AR, says Steven Schweon, RN, MPH, MSN, CIC, LTC-CIP, CPHQ, FSHEA, FAPIC, an infection preventionist based in Saylorsburg, PA, and a member of the Emerging Infectious Diseases task force at APIC.

“The purpose of the antibiogram is to make sure that the antibiotic that is most likely to be ordered will have the highest chance of being effective,” says Schweon. “The antibiogram improves the prescriber’s ability to figure out which is the most effective antibiotic and what is the most common pathogen within that facility.”

Schweon offers the following simplified scenario: A nursing home resident has symptoms of a UTI that meet the Loeb Minimum Criteria for the Initiation of Antibiotics in Long-Term Care Residents. Note: The Loeb criteria are clinical assessment criteria designed to assist with diagnosis and treatment. The McGeer criteria and the National Healthcare Safety Network (NHSN) criteria are designed for retrospective use to determine what should count as an infection for surveillance purposes.

“Without the antibiogram, the prescribing clinician has to guess what bug is causing this resident’s UTI and what the best antibiotic is to improve their quality of life before their culture comes back from the lab,” says Schweon. “With the antibiogram, the prescribing clinician can look at it to determine, ‘In this nursing home, Escherichia coli (E. coli) is the most common source of UTIs, and ampicillin is the most effective antibiotic against E. coli. So, based upon the presumptive evidence, I suspect the resident has E. coli and that ampicillin will be effective.’”

Steven Schweon, RN, MPH, MSN, CIC, LTC-CIP, CPHQ, FSHEA, FAPIC, infection preventionist and member of the Emerging Infectious Diseases task force at APIC

In other words, the antibiogram increases the prescribing clinician’s odds of choosing the correct antibiotic earlier in their treatment, explains Schweon. “If the resident is not getting the correct antibiotics or is receiving unnecessary antibiotics, they are at risk of side effects and adverse reactions. For example, it would be tragic for a resident to take an antibiotic that they don’t need and wind up developing a Clostridioides difficile (C. diff) infection, with environmental contamination of feces. That would pose a risk to everyone in the facility.”

Note: C. diff associated with antimicrobial use adds over 200,000 infections and 13,000 deaths to the annual toll of AR, according to the CDC.

However, if the resident does receive the correct antibiotic because the antibiogram helped the prescriber make a more informed clinical decision, the resident may have less pain and get well more quickly, says Schweon. “That will directly impact their quality of life—and reduce their chances of, for example, dehydration, falls, or even urosepsis as a result of the UTI.”

2. Obtain an antibiogram

Ways to obtain an antibiogram include the following:

Ask the lab for a nursing home-specific annual antibiogram. “The IP can check with the referral lab to see if an antibiogram specific to the nursing home’s resident population can be obtained,” says Schweon. “Depending on the nursing home’s size, there may not be enough cultures for the lab to develop an antibiogram. Or, the lab may charge hundreds and hundreds of dollars for an annual antibiogram. That financial burden also could be a barrier for some facilities.”

Although nursing homes face more challenges with obtaining antibiograms than acute-care hospitals, “a multidisciplinary group … should formulate a plan for antibiogram development that meets the individual needs of the LTCF,” suggests the authors of “What’s New in Antibiograms? Updating CLSI [Clinical Laboratory and Standards Institute] M39 Guidance With Current Trends” from the Aug. 2, 2022 Journal of Clinical Microbiology.

Nursing homes taking this step is important because “the susceptibility patterns of isolates encountered in [nursing homes] are often unique to that facility,” according to the authors. In some cases, antibiogram development may need to include “combining data from multiple years” or “combining species (if applicable).”

Ask referring hospitals to provide their antibiogram. “If a nursing home-specific antibiogram isn’t possible, your next best bet is to request a copy of the referring hospital’s antibiogram,” says Schweon. “This will give you a good picture of what’s going on in the community.”

“Many times, nursing homes just don’t do enough cultures to be able to tease out susceptibility patterns for an annual antibiogram,” agrees Burdsall. “So, the antibiograms from your primary admitting acute-care facilities can be an excellent tool to allow prescribers to make a best guess on what works with prevailing organisms in your nursing home.”

However, where the resident was admitted from becomes an important factor in this scenario, advises Burdsall. “If one resident admitted from Hospital A develops a UTI and one resident from Hospital B develops a UTI, Hospital B’s antibiogram may look very different from Hospital A’s antibiogram. To ensure that the prescribing clinician knows which antibiotic is most likely to work for each resident’s UTI, ideally you will be able to provide the clinician with the antibiogram from Hospital A for the first resident and from Hospital B for the second resident.”

Obtaining antibiograms from each admitting hospital may be easier now than in the past, says Burdsall. “Hospitals and nursing homes both have a financial stake in reducing hospital readmissions, opening the door for improved communication, including shared antibiograms.”

Ask the lab for its antibiogram. “Sometimes, a private lab will be willing to provide its own antibiogram,” says Schweon. “However, geographically you may not know where all those cultures are coming from. If your referral lab works with healthcare providers hundreds of miles away from you, that antibiogram will not be as useful as an antibiogram from your local community hospital.”

4. Learn how to interpret an antibiogram

“Once the antibiogram is obtained, the IP has to have a pretty good understanding of what it means,” points out Schweon. “According to CMS, the IP ‘owns’ the antibiotic stewardship program, so it’s key for you to have an understanding of the antibiogram before you talk to the prescribers and your nursing staff about it. Several terrific resources are available to help you understand and interpret the antibiogram.”

These resources include the following:

5. Educate prescribers and nursing staff on the antibiogram

The IP should have conversations with all prescribers about the antibiogram, says Schweon. “The prescribers need to know how to access the antibiogram, and they need to be able to understand how to read it and use it for optimal clinical prescribing.”

Nursing staff also should understand the significance of the antibiogram, adds Schweon. “You could even post it on the units. The goal is to make it widely accessible and to be sure everyone understands what it means.”

Caralyn Davis

Caralyn Davis is a freelance writer specializing in the post-acute care sector. Email her at: caralynd@outlook.com.