To the Editor
To combat the worldwide crisis of antimicrobial resistance, the World Health Organization (WHO) has developed its Global Action Plan on Antimicrobial Resistance.1 This plan outlines several objectives including: increasing education about appropriate antimicrobial use and promoting antimicrobial stewardship. To help achieve these goals, the WHO urges health care institutions to produce and distribute locally derived antibiograms to clinicians. The expectation is that antibiogram use will improve empiric antimicrobial prescribing and decrease inappropriate antimicrobial use. However, whether physicians are receiving sufficient education about antibiograms is not known.
In this study, we evaluated medical trainees' knowledge and education regarding antibiograms. A 20-item survey (https://www.surveymonkey.com) was sent electronically to house staff in US training programs. The survey contained five test-of-knowledge questions: Two questions involved recognizing the definitions of “antibiogram” and “breakpoint” and three questions required respondents to interpret specific components of sample antibiograms (sections of sample antibiograms were highlighted and respondents were asked to interpret what the sections represented). The Institutional Review Board at the University of California, Davis Medical Center, approved this study.
All data were analyzed using SAS(r) version 9.3. (SAS Institute, Inc. Cary, NC). A non-parametric analysis of variance (the NPAR1WAY procedure) was used to compare antibiogram interpretation question scores between different groups. All questions were weighted equally and mean percent correct scores were calculated based on number correct per participant. P-values of less than 0.05 were considered significant.
A total of 692/4211 invited house staff participated; 74.4% were residents and 25.6% were interns. Most respondents had graduated from US medical schools (88.7%) and were training at academic institutions (87.7%). Internal medicine trainees comprised 41.8% of respondents, followed by emergency medicine (20.9%), pediatrics (11.9%), family medicine (9.0%), surgery (8.7%), and obstetrics-gynecology (6.8%). Overall, 327 (49.0%) had completed an infectious diseases (ID) clinical rotation.
Table 1 shows the survey question responses. Almost all respondents were familiar with what an antibiogram is and correctly identified the definition of “antibiogram”. However, only 62.2% correctly identified the definition of “breakpoint”. Only 77.9% of respondents knew how to obtain their institution's antibiogram. For the antibiogram interpretation questions, 90.9% (549/604) of respondents correctly identified that a highlighted number in a sample antibiogram represented the percent of Escherichia coli isolates that were susceptible to ceftriaxone, and 85.8% (507/591) identified that a highlighted number represented the percent of methicillin-resistant Staphylococcus aureus isolates that were susceptible to levofloxacin. Only 68.0% (404/594) identified that a highlighted section represented the breakpoint for trimethoprim/sulfamethoxazole. Table 2 summarizes the mean percent correct scores for respondents (n=554) who completed all three antibiogram interpretation questions. Mean percent correct scores were significantly higher for residents than those for interns and for respondents who had completed an ID rotation. Differences were not observed among the various medical specialties.
Table 1. House Staff Responses to Questions about Antibiograms.
| Question | % |
|---|---|
| I am familiar with what an antibiogram is: | |
| Yes | 93.4 |
| No | 6.6 |
| I know how to obtain the antibiogram for my institution: | |
| Yes | 77.9 |
| No | 22.1 |
| I know how to interpret an antibiogram: | |
| Strongly agree | 19.8 |
| Agree | 49.5 |
| Neutral/unsure | 21.3 |
| Disagree | 7.5 |
| Strongly disagree | 1.9 |
| Identified the definition of “antibiogram” | |
| Correct | 92.5 |
| Incorrect | 7.5 |
| Identified the definition of “breakpoint” | |
| Correct | 62.2 |
| Incorrect | 37.8 |
Table 2. Mean Percent Correct Scores for Antibiogram Interpretation Questions.
| Variable | Mean Percent Correct Score, % | P-value* |
|---|---|---|
| Training level | 0.004 | |
| Resident (n=407) | 84.1% | |
| Intern (n=147) | 76.2 | |
| Completed infectious diseases rotation | 0.024 | |
| Yes (n=279) | 84.7 | |
| No (n=275) | 79.2 | |
| I know how to interpret an antibiogram | <0.0001 | |
| Strongly agree (n=105) | 94.3 | |
| Agree (n=282) | 87.9 | |
| Neutral (n=114) | 70.2 | |
| Disagree (n=43) | 52.7 | |
| Strongly disagree (n=10) | 46.7 | |
| Medical specialty | 0.390 | |
| Internal medicine (n=236) | 81.9 | |
| Emergency medicine (n=122) | 79.5 | |
| Family medicine/obstetrics-gynecology (n=83) | 86.0 | |
| Pediatrics (n=69) | 80.0 | |
| Surgery (n=44) | 78.0 |
Non-parametric analysis of variance
Sources of education about antibiograms (respondents could choose more than one answer) included the following: 69.6% of respondents were taught about antibiograms during internship or residency, 45.4% in a medical school course, 19.0% by an ID physician, and 14.8% by a pharmacist. Notably, 15.1% did not receive any formal training in antibiograms. Of those who had completed an ID rotation, only 33.0% received antibiogram education during the rotation. Overall, 73.7% of respondents expressed an interest in receiving more training in antibiogram interpretation. Preferred settings for future training were “lectures during internship and residency” (88.3%), “during clinical rounds” (53.8%), “during medical school lectures” (46.0%), and “online courses” (34.7%).
The present study illustrates that medical trainees are not receiving adequate education about antibiograms. More than half of our respondents were not taught about antibiograms in medical school and many had not received any antibiogram education. Although we found that most house staff had some familiarity with antibiograms and correctly answered basic antibiogram questions, over one third did not correctly answer more challenging questions, such as the definition or interpretation of a breakpoint.
Notably, two-thirds of respondents who had spent time on an ID service had not been taught about antibiograms during the rotation. Perhaps ID physicians assume that house staff receive such education elsewhere or they place more emphasis on implementing institutional antimicrobial stewardship programs. It has been reported that passive educational programs (e.g.; didactic lectures) do not curtail antimicrobial prescribing as effectively as do stewardship programs that incorporate active interventions (e.g.; recommendations for antimicrobial selection or de-escalation).2 However, such active interventions may be more successful when prescribers are knowledgeable about their local antibiogram.
Several other factors may negatively impact antibiogram education. For example, physicians often seek guidance about antimicrobial prescribing from pharmacists or non-ID physicians, yet these persons may have insufficient antibiogram knowledge.3-5 As a result, medical trainees may be learning prescribing practices from sources who do not emphasize the value of antibiograms. Another factor may be that clinicians lack of accessibility to timely and accurate institutional antibiograms. Despite recommendations that hospitals provide antibiograms to clinicians on an annual basis, a number of studies have revealed that laboratory and hospital compliance with antibiogram preparation and distribution is suboptimal.6-8 Along with our finding that 22% of survey respondents did not know how to obtain their institution's antibiogram, the results of these studies suggest that another barrier to antibiogram education is poor availability of antibiograms. Finally, effective antibiogram education may be hindered by the lack of clarity about how best to use antibiograms to guide antimicrobial therapy. For over a decade, the US Centers for Disease Control and Prevention has instructed clinicians to “use local data, know your antibiogram”.9,10 Yet, practical recommendations for their use are scarce; the paucity of outcomes data has impeded progress in this area. Further assessment of each of these factors may identify targets for antibiogram education improvement.
Prior studies have raised awareness that medical trainees are not receiving adequate education about antimicrobial resistance and antimicrobial prescribing.3,4 This study adds to these concerns by highlighting that antibiogram education is deficient.
Highlights.
Antibiotic overuse is driving the worldwide crisis of antimicrobial resistance.
All health care workers must become skilled in appropriate antimicrobial prescribing.
The WHO recommends the use of antibiograms to guide antimicrobial prescribing.
Physicians are not receiving adequate education about antibiograms.
Acknowledgments
The authors would like to thank the house staff who participated in this study.
Financial support: This work was funded by University of California, Davis Medical Center intramural funds. The project described was also supported by the National Center for Advancing Translational Sciences (NCATS), National Institutes of Health (NIH), through grant #UL1 TR000002.
Footnotes
Potential conflicts of interest: All authors: no reported conflicts.
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