Abstract
Background:
In 2019, the Infectious Diseases Society of America (IDSA) released updated guidelines for the treatment of community-acquired pneumonia (CAP). These guidelines recommend a new preferred duration of therapy of no less than a total of five days if the patient has achieved clinical stability. This quality improvement project will determine whether comprehensive education to pharmacists and providers impacts the total duration of antibiotic therapy for patients treated for CAP.
Objectives:
The primary endpoint was to evaluate the impact of the intervention on antibiotic duration of therapy for patients with CAP in the post-intervention group. The secondary endpoints were the impact on duration of therapy for patients with an antibiotic switch or patients with an outpatient prescription for antibiotics for CAP at discharge.
Methods:
This study was an IRB-approved, retrospective cohort study. Education was provided to clinical pharmacists during scheduled monthly meetings for a 6-month period starting in August 2024. Hospitalists were educated in a separate meeting prior to post-intervention data collection. Data were collected from February 1, 2024 to July 31, 2024 and September 1, 2024 to February 28, 2025 for the pre- and post-intervention cohorts, respectively.
Results:
The pre- and post-intervention cohorts include 116 and 145 patients, respectively. Total duration of therapy decreased by 0.9 days after the intervention (7.3 ± 2.7 and 6.4 ± 2 days, respectively, in the pre- and post-intervention groups; P = .005). Duration of therapy decreased by 1 day for patients with an antibiotic switch after the intervention (seven days [6-10] and six days [5-8] in the pre- and post-intervention groups, respectively; P < .001). Duration of therapy for patients with an outpatient antibiotic prescription decreased by 1.5 days after the intervention (8.8 ± 3 and 7.3 ± 2.3 days, respectively, in the pre- and post-intervention groups; P < .01).
Conclusions:
The pharmacist-led education resulted in a statistically significant reduction in the duration of therapy for patients treated for CAP. There was a statistically significant reduction in the duration of therapy after the intervention in patients who had an antibiotic switch and those who had an outpatient antibiotic prescription for CAP at discharge.
Background
Pneumonia is the fourth most common principal diagnosis for hospitalized patients, with over an estimated 740 000 hospitalizations, and community acquired pneumonia (CAP) has an annual incidence of 24.8 cases/10 000 adults in the United States. For geriatric patients, the incidence is higher, with 63.0 cases/10 000 adults 65 to 79 years old and 164.3 cases/10 000 adults 80 years or older.1,2 In 2019, the Infectious Disease Society of America (IDSA) released updated guidelines for the treatment of CAP, which recommended a new preferred duration of therapy of no less than a total of five days if the patient has achieved clinical stability. 3
Patients who receive an extended antibiotic duration of therapy are at an increased risk of antibiotic resistance development, with up to a 7% absolute risk increase in resistance carriage for each antibiotic day of treatment. 4 Patients who receive an extended antibiotic duration of therapy are also at an increased risk for antibiotic-associated adverse events, with 4% increased odds with each additional day of antibiotic therapy. 5 Longer durations of antibiotic therapy for CAP have been shown to lead to an increased risk of C. difficile infection by up to 20%. 6
Many patients with CAP are likely to be discharged from an inpatient stay prior to completion of antibiotic therapy, and providers who prescribe antibiotics at discharge may increase the duration of therapy when potentially not indicated. A previous retrospective review found patients treated for CAP who received an outpatient prescription would be prescribed three to 5 days of antibiotics at discharge, after already receiving a median of 4 days of inpatient therapy. This practice resulted in total treatment durations of seven to nine days, exceeding guideline recommendations for most patients and potentially contributing to unnecessary antibiotic exposure. 7
Baptist Health Lexington (BHLex) is a 434 bed community hospital with a pharmacist co-led Antimicrobial Stewardship team. Clinical pharmacists attend multidisciplinary rounds (MDR) on the majority of clinical units daily on weekdays. The antimicrobial stewardship team identified CAP as a target disease state for stewardship opportunities, as it is among the top primary diagnoses for inpatient admission at this facility. In addition to routine cultures, BHLex has a respiratory pathogen panel which detects 18 viruses and four bacteria, but it’s use has shown limited impact on prescribing of antimicrobials for CAP. Ampicillin-sulbactam or ceftriaxone plus one of azithromycin or doxycycline are the first-line recommendations for treatment of CAP. The use of respiratory fluoroquinolones such as levofloxacin is discouraged at BHLex due to their known association with serious adverse drug events. 8 BHLex has a guidance document on antibiotic duration of therapy, which recommends five days of therapy for patients with CAP not caused by MRSA or Pseudomonas aeruginosa.
Primary Objective: The primary objective was to assess the impact of comprehensive education on the duration of therapy for CAP.
Secondary Objectives: The secondary objectives were the impact on the duration of therapy for patients with an antibiotic switch or with an outpatient prescription. These objectives were hypothesized to be contributors to extended durations of antibiotic therapy. Other data points included patients who had sputum cultures, MRSA PCR nares, and initial procalcitonin levels collected.
Methods
Study Design: This study is an IRB-approved, retrospective cohort study that occurred at BHLex which was conducted during two 6-month periods before and after the intervention. The pre- and post-intervention periods were February 1, 2024, to July 31, 2024, and September 1, 2024, to February 28, 2025, respectively. There was a 1-month grace period between the two cohorts. Data were collected through a retrospective chart review using the electronic health record and internal reporting tools.
Inclusion Criteria: Patients were included if the following criteria were met: hospitalization for at least 48 hours, diagnosis with pneumonia within 48 hours of admission, administration of antibiotic treatment indicated for pneumonia, and age >18 years.
Exclusion Criteria: Patients were excluded if one of the following criteria were met: critically-ill, presence of a palliative care consult during admission, concomitant bacteremia, received antibiotics for pneumonia for a separate admission in the last 14 days, or immunocompromised.
Days of Therapy: A day of therapy is defined as any calendar day in which a patient receives at least one dose of an antibiotic. 9 Patients who received two or more different antibiotics on the same day were considered as receiving one day of therapy. For inpatient treatment of CAP, guidelines do not recommend monotherapy for most patients, so days of therapy were determined from this definition. Total duration of therapy was collected, including both inpatient and outpatient durations of therapy. Inpatient duration of therapy was determined by the number of days antibiotics were administered with an indication of pneumonia. Outpatient duration of therapy was determined by the number of days of therapy prescribed at discharge.
Additional Clinical Data
Antibiotic Switch: The presence of an inpatient antibiotic switch was assessed for contribution to an extended duration of therapy. Any change in antibiotic with an indication of pneumonia that was ordered during inpatient admission was considered an antibiotic switch. This includes intravenous (IV) to oral (PO), changing to a different IV antibiotic, or changing PO antibiotics. For example, if the patient was empirically started on piperacillin/tazobactam but was changed to ceftriaxone, it was considered an antibiotic switch. However, if the patient switched therapy from ceftriaxone to cefuroxime at discharge and did not get any cefuroxime during the inpatient stay, it was only considered as having an outpatient prescription and not an antibiotic switch. This variable is the total number of days a patient received antibiotic therapy who also had an antibiotic switch. This includes if the patient also received a prescription at discharge.
Outpatient Prescription: The presence of an outpatient prescription at discharge was assessed for appropriateness and contribution to an extended duration of therapy. Patients with an outpatient prescription were stratified based on whether the prescription was ordered before or after 5 days of inpatient antibiotics. This was done to see whether patients were receiving antibiotic prescriptions at discharge after completing the guideline-recommended duration of therapy of five days. Patients were stratified into two groups: those who received less than five days of inpatient antibiotics and those who received at least 5 days of inpatient antibiotics.
Data for blood cultures were collected to rule out bloodstream infections and data on sputum cultures were collected to assess appropriateness of treatment of CAP based on pathogens isolated. Other labs collected included MRSA PCR nares results, presence of a procalcitonin order, and initial procalcitonin value.
Antibiotics Used: Administered antibiotics were assessed for appropriate antibiotic choice for treatment of CAP and divided into six antibiotic categories based on spectrum of activity. The antibiotics listed included those recommended for CAP and any others with an indication of pneumonia during treatment. The number of different antibiotics used for each patient was also collected to assess if antibiotic switches impacted duration of therapy (Table 1).
Antibiotic Categories.
Demographics: Sex, age, length of stay, and the presence of an infectious disease consult during inpatient admission were also collected.
Statistics: Parametric continuous variables were analyzed using an unpaired t-test. Non-parametric continuous variables were analyzed using a Mann-Whitney U test. Dichotomous continuous variables were analyzed using an odds ratio.
Intervention
The intervention involved educating clinical pharmacists and hospitalists on aligning current antibiotic prescribing practices for CAP with IDSA guidelines and institutional expectations. Both verbal and written materials with information from the IDSA guidelines and BHLex internal guidance were provided to participants. The recommended therapy for most patients with CAP on the guidance document was ampicillin/sulbactam or ceftriaxone plus either azithromycin or doxycycline (Supplemental 1).
Clinical pharmacists were educated during scheduled meetings for a 6-month period starting in August 2024 for five minutes once a month. Clinical pharmacists were encouraged to determine if current antimicrobial durations of therapy were appropriate given patients’ current risk factors and clinical improvement based on stability criteria included in the education. Stability criteria included resolution of abnormal vital signs such as heart rate, respiratory rate, oxygen saturation, blood pressure, and temperature, as well as return of ability to eat and/or return to normal mentation. If appropriate, pharmacists were encouraged to recommend to providers to shorten the ordered duration of therapy or discontinue antibiotics if the patient had already received five days of therapy. Pharmacists were also educated to look for antibiotic switches during the patient’s treatment and outpatient prescriptions at discharge for opportunities to shorten antibiotic duration of therapy.
Hospitalists were educated in a separate meeting prior to post-intervention data collection for a 20 minute education session and encouraged to discuss the appropriate duration of therapy for patients with CAP with pharmacists during MDR. Most hospitalists were present, but a follow up email was sent after the meeting. The emphasis was the discussion of appropriate days of therapy for both providers and pharmacists during MDR.
Results
There were more patients in the post-intervention group, but overall, the demographics were similar. The median length of stay was six days in each group (Table 2).
Demographics.
The mean total antibiotic duration for patients with CAP decreased following the intervention, from 7.3 ± 2.7 days pre-intervention to 6.4 ± 2.0 days post-intervention (P = .005; Figure 1).

Total mean duration of therapy.
Patients were assessed for the presence of an antibiotic switch for treatment of CAP during hospital stay. To further characterize inpatient antibiotic use, the frequency and nature of antibiotic switches were also examined. An antibiotic switch was present in 51.7% and 42.8% of patients in the pre- and post-intervention cohorts, respectively. There was a decrease in the median days of therapy for patients with an antibiotic switch after the intervention from seven [6-10] to six [5-8]; (P < .001)
As patients received more different antibiotics during their treatment course, there was a trend with more days of antibiotic therapy. Most patients in both cohorts received either two, three, or four different antibiotics during their treatment course (Figure 2).

Number of different antibiotics ordered.
There were 48 (41.4%) and 71 (49.0%) patients who received an outpatient prescription in the pre- and post-intervention cohorts, respectively (P = .21). In these subgroups, antibiotic duration of therapy decreased by 1.5 days, from 8.8 ± 3 days to 7.3 ± 2.3 days after the intervention; (P < .01). Outpatient prescription days of therapy decreased from 3.8 ± 2.1 days to 3.1 ± 1.6 days in the pre- and post-intervention cohorts, respectively; (P = .03). Patients who did not receive an outpatient prescription had a decrease in days of therapy by 0.6 days, from 6.2 ± 1.8 days to 5.6 ± 1.3 days, after the intervention; (P = .04).
After the intervention, patients receiving an outpatient prescription were more likely to have a shorter inpatient duration of therapy (OR = 0.46, 95% CI, 0.22-0.97; P = .04; Table 3). In both groups, the total inpatient duration of therapy was greater than five days, so most outpatient antibiotic prescriptions may not have been necessary, as patients discharging from the hospital likely had met clinical stability criteria. In the post-intervention group, patients who received an outpatient prescription had a significantly shorter total duration of therapy; (P < .01), and the duration of the outpatient prescription itself was also significantly shorter; (P = .03).
Outpatient Prescription Data.
Blood and sputum cultures were assessed for positive results to exclude patients with bloodstream infections and review isolated organisms causing pneumonia. There were 107 blood and 36 sputum cultures in the pre-intervention and 134 blood and 39 sputum cultures in the post-intervention collected, respectively There were only nine (25%) and five (12.8%) positive sputum cultures with significant growth, respectively, in the pre- and post-intervention cohorts. Normal respiratory flora was not considered to be a positive sputum culture. There were 89.4% and 93.4% of patients in the pre- and post-intervention groups who tested negative for their MRSA PCR nares screen (Table 4).
Additional Lab Results.
Procalcitonin levels of <0.25 ng/L suggest a lower likelihood of bacterial infection. There were 95 and 127 patients who had procalcitonin ordered within 24 hours of admission, respectively, in the pre- and post-intervention groups, and of those, only 36 (37.9%) and 54 (42.5%) patients had an initial procalcitonin of ≥0.25 ng/L.
After the intervention, there was an increase in patients receiving a preferred IV β-lactam and/or an atypical agent by 7.4% and 12.9%, respectively. Conversely, there was a decrease in patients receiving an anti-pseudomonal or anti-MRSA agent by 22.8% and 13%, respectively, after the intervention (Figure 3).

Antibiotics prescribed in the pre- and post-intervention cohorts.
Discussion
This study found a 0.9-day reduction in the duration of therapy for patients with CAP after pharmacist-led comprehensive education. This study also found a reduction in duration of therapy for patients who had an antibiotic switch during admission and an outpatient prescription at discharge. After the intervention there was a decrease in the number of patients receiving therapy with both anti-MRSA and anti-pseudomonal agents, despite updates to the IDSA guidelines recommending shorter durations, prolonged antibiotic therapy remains common in practice. Vaughn et al 10 found that 67.8% of patients received excess antibiotic therapy, and antibiotics at discharge accounted for 93.2% of excess duration. Yi et al 11 found in hospitalized patients with CAP, that 74% of patients aged 18-64 and 71% of patients aged 65 years or older had a median duration of 9.5 days.
Several institutions have targeted CAP for disease-state based stewardship. Advic et al 12 implemented an intervention similar to this study utilizing education and prospective feedback with the goal of decreasing the duration of therapy. After their intervention, there was a significant reduction in the median duration of therapy (seven vs ten days; P < .001). However, the sample size of this study was smaller and did not assess impact on antibiotic prescriptions at discharge. Foolad et al 13 implemented a multifaceted approach of providing pocket cards to practitioners, updating local guidance, and antibiotic stewardship team members performing prospective audit and feedback. After Foolad et al’s 13 intervention, there was also a significant reduction in median days of therapy (six vs nine days; P < .001). However, this study took place at multiple sites, and only infectious disease pharmacists performed prospective audit and feedback to providers. After the current study’s educational intervention, pharmacists were encouraged to review antibiotic duration for patients with CAP based off clinical stability criteria to discuss at MDR. If criteria were met, pharmacists were asked to recommend 5-day courses of antibiotics or discontinuation of antibiotics in patients already treated for at least five days.
At BHLex, there was a 1-day reduction in the duration of therapy among patients who had an antibiotic switch following the intervention. In this study, the percentage of patients who had an antibiotic switch decreased after the intervention from 51.7% to 42.8%, which may be due to greater alignment of initial selection to guideline concordant therapy. Patients who received three or fewer different antibiotics during their course of therapy increased from 64.5% to 80% after the intervention. This study highlights antibiotic switching, regardless of route, as a potential contributor to longer than recommended duration of therapy. The primary concern with IV-to-IV switching is that durations of therapy would restart without a provider recognizing the previously administered antibiotic duration. For example, if a patient was given two days of piperacillin-tazobactam and switched to ceftriaxone, and the ceftriaxone was ordered for five days, the patient could receive seven days of antibiotics instead of guideline directed duration. Several studies have shown a decrease in the duration of therapy without a decrease in efficacy after early IV-to-PO antibiotic switching.14,15 However, the impact on the duration of therapy has not previously been assessed in patients whose IV therapy is switched to another IV therapy. Although antibiotic switches may contribute to extended durations of therapy, they could also indicate that there are patients requiring changes to antibiotic therapy due to lack of improvement on initially ordered antibiotics. Determining this is beyond the scope of this study.
Following the intervention, there was a reduction in the total duration of therapy by 1.5 days among patients who received an antibiotic prescription at discharge. Despite this reduction, a significant proportion of patients received durations of therapy beyond guideline recommendations. Yi et al 11 assessed a nationwide sample of patients hospitalized with CAP and found more than 70% of patients may have received excessive treatment duration and 80% of patients received an antibiotic prescription upon discharge. This study found a median outpatient prescription duration of six days in patients 18-64 years old and five days in patients 65 or older. In the post-intervention cohort of the present study, 49% of patients received an antibiotic prescription, however 78.9% of this subgroup of patients received a total antibiotic duration of therapy greater than five days. McCarthy et al 16 found the presence of an outpatient prescription increased as LOS decreased, which is similar to the present study’s findings, however the present study looked at clinical criteria to recommend discontinuation or reduction in duration of therapy. The education was effective at reducing overall and outpatient duration of therapy, but a large proportion of patients still received an antibiotic prescription at discharge contributing to durations beyond guideline recommendations.
The educational intervention reiterated guideline-recommended antimicrobials for treatment of CAP. Specifically, the guidelines do not recommend using anti-pseudomonal and anti-MRSA antibiotics for empiric treatment for most patients. The educational intervention also included information on risk factors for and when to empirically initiate anti-pseudomonal and anti-MRSA therapy for patients with CAP. In this study, sputum cultures were collected for 36 (31%) and 39 (26.9%) patients, respectively, in the pre- and post-intervention groups, with nine and five cultures resulting in significant growth. Colmerauer et al 17 found a reduction in broad-spectrum antibiotic duration in patients admitted with CAP from 2 to 0 days after implementation of a new CAP order set. This institution currently does not have a designated order set for CAP, but there was a reduction in anti-MRSA and anti-pseudomonal therapy. Despite there being only one (0.86%) and two (1.38%) P. aeruginosa sputum isolates in each of the pre- and post-intervention cohorts, 49% and 26.2% of patients received at least one dose of an antipseudomonal agent. P. aeruginosa has been described as occurring in 2% of patients with CAP without prior colonization, which is consistent with the data collected. 18 Despite there being only one MRSA sputum isolate in each of the pre- (0.86%) and post-intervention (0.69%) cohorts, 30.2% and 17.2% of patients, respectively, received at least one dose of an anti-MRSA agent. MRSA has been described as the causative pathogen in 0.7% of patients with CAP despite almost one-third of patients receiving anti-MRSA therapy in this study. 19 The usage of empiric anti-MRSA treatment versus standard antibiotic therapy in hospitalized patients with pneumonia has not been shown to have a mortality benefit, but has higher incidences of acute kidney injuries. 20 The present study found a reduction of anti-MRSA therapy initiation by 13% after the intervention, but the rate of prescribing still much higher than the locally identified incidence of MRSA CAP. While the intervention was effective in reducing both antipseudomonal and anti-MRSA therapy prescribing, opportunity still exists for further reduction in empiric use of these agents.
In this study, the MRSA PCR nares screening was negative for 89.4% and 93.4% of tests in the pre- and post-intervention, respectively. MRSA PCR nares have a high negative predictive value, which can give reasonable confidence to recommend discontinuation of anti-MRSA therapy in patients with pneumonia. 21 After the intervention, there was a decrease in MRSA PCR nares screened from 56.9% to 52.4%. MRSA PCR nares should only be ordered in patients initiated on anti-MRSA therapy for CAP. A potential future target would be to initiate less anti-MRSA therapy in this patient population without risk factors and therefore screen less. This is supported by most of the MRSA PCR screens in this study resulting as negative.
Initial procalcitonin may be used to support the recommendation of discontinuation of antibiotics in appropriate patients. A future analysis on this patient population could be warranted as most patients in this study had an initial procalcitonin collected, but only 37.9% and 42.5% of patients had an initial procalcitonin of ≥0.25 ng/L. Repeat levels were not assessed due to the inconsistency of ordering among the patient population. Procalcitonin has a negative predictive value of 82.2% in patients with community-acquired disease who are not immunocompromised. 22 Appropriate timing of procalcitonin to account for peak levels was also not assessed. However, the data collected may indicate that a significant proportion of patients in this study could have had viral rather than bacterial pneumonia. Future efforts could be given to more standardized ordering and/or trending of procalcitonin levels to facilitate streamlining of antibiotic durations of therapy.
Corticosteroid use was not evaluated in this study. Critically ill patients were excluded which would eliminate most patients presenting with severe CAP. Further distinguishing of non-severe from severe CAP was beyond the scope of this study.
There are multiple future directions that could be taken at this institution to further optimize durations of therapy or help determine appropriateness of current durations in subpopulations. There is currently a lack of structure for pharmacists’ intervention at discharge for outpatient prescription durations of therapy. A potential solution for extended antibiotic durations at discharge could be creation of a queue for pharmacists to verify discharge orders and intervene prior to prescriptions being sent to an outpatient pharmacy, but this would require additional staff support. Determining if CAP duration of therapy education focusing on 5 or less days can be applied for treatment of patients who are immunocompromised or critically-ill would be useful given their exclusion from this study. Finally, a re-evaluation of procalcitonin levels for CAP could be part of an order set to allow the provider or pharmacist to assess the appropriateness of antimicrobial therapy in this patient population.
This study was retrospective in nature. There were multiple contributing factors that could increase the duration of therapy including: escalation due to a lack of clinical improvement, de-escalation through antibiotic switches with restarted antibiotic course durations, and outpatient prescriptions that do not account for the duration of therapy already completed. During the writing process of this manuscript the American Thoracic Society published updated guidance which recommends three days of therapy for certain patients with CAP. 23 This recommendation could not be included in the present study, but will be a future directive at this institution to further optimize antibiotic durations of therapy for CAP. This study was also a recommendation-based study at a single site, so the duration of therapy adjustments recommended by pharmacists were subject to acceptance or denial by provider discretion. Another limitation is provider and pharmacist turnover at the institution, so education during orientation could be a future avenue. Critically-ill and immunocompromised patients were excluded from this study, and it cannot be determined whether the intervention would be successful in reducing the duration of therapy for patients with CAP in these populations.
Conclusion
Comprehensive education was effective at reducing the overall duration of therapy in non-critically-ill, immunocompetent patients with CAP. In addition to this, patients who had an antibiotic switch and/or patients with a prescription at discharge also saw a decrease in duration of therapy. This study shows evidence of the impact of antibiotic switching, regardless of route, on the duration of therapy. There was a reduction in outpatient prescription antibiotic duration of therapy, but there is still excessive antibiotic use beyond guideline recommendations. There is an opportunity for further stewardship by pharmacists to assess for completed therapy at discharge prior to the provision of outpatient antibiotic prescriptions. The intervention was effective in reducing the overall antibiotic duration of therapy across several patient groups, but a large proportion of patients still received an extended duration of therapy.
Supplemental Material
sj-docx-1-hpx-10.1177_00185787251390774 – Supplemental material for Impact of Comprehensive Education on Antibiotic Duration of Therapy for Community-Acquired Pneumonia in a Community Hospital
Supplemental material, sj-docx-1-hpx-10.1177_00185787251390774 for Impact of Comprehensive Education on Antibiotic Duration of Therapy for Community-Acquired Pneumonia in a Community Hospital by Keaton Prebble and Layla Marefat in Hospital Pharmacy
Footnotes
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
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References
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