PSHP 2026 Residency Conference

Purpose: The purpose of this study was to compare outcomes in obese patients with aerobic gram-negative rod (GNR) bacteremia treated with either high- or low-bioavailability antibiotics for oral stepdown therapy.
Methods: This retrospective single‑center cohort study compared clinical outcomes in adult patients with a body mass index ≥ 30 kg/m2 who received oral stepdown with either a high‑bioavailability (sulfamethoxazole-trimethoprim, fluoroquinolones) or low‑bioavailability (beta-lactams) agent for uncomplicated GNR bacteremia. All patient and clinical data were obtained from the electronic health record by automated reports and manual review, then compiled in Excel. Patients were identified from Lehigh Valley Health Network Cedar Crest, Muhlenberg, Hecktown Oaks, Hazleton, Schuylkill, Pocono, and Carbon campuses. The primary outcome was 30-day bacteremia recurrence, which was analyzed descriptively due to limited events. Secondary outcomes were 90-day bacteremia recurrence, 30- and 90-day all-cause mortality, length of stay, and 30- and 90-day all-cause readmission, which were analyzed using both descriptive and inferential statistics.
Results: A total of 203 individuals were included, with 127 in the high‑bioavailability group and 76 in the low‑bioavailability group. Urinary sources accounted for 75% of infections, E. coli for 66% of pathogens, and most patients received 3 days of IV therapy followed by 7 days of oral step‑down, typically with a fluoroquinolone (55%). No bacteremia recurrences occurred at 30 days, and only one recurrence was observed in the low‑bioavailability group at 90 days. All secondary outcomes were similar between groups, apart from all‑cause 30‑day readmission, which was higher in the high‑bioavailability step‑down group.
Conclusion: One 90‑day bacteremia recurrence occurred in a patient receiving oral cefpodoxime 100 mg twice daily, a notably low dose. The findings of this study suggest that oral stepdown for uncomplicated GNR bacteremia in obesity may be more nuanced than distinguishing between the bioavailability of agents. Clinical factors and real‑world dosing practices may influence outcomes, extending beyond what oral bioavailability alone can predict.

Identify whether oral third generation cephalosporins are as effective as standard of care, ceftriaxone or vancomycin, for the treatment of penicillin-non-susceptible, ceftriaxone-susceptible alpha-hemolytic Streptococcal infections. This retrospective chart review evaluated patients > 18 years old admitted to St. Luke’s University Health Network for treatment of penicillin-non-susceptible, ceftriaxone-susceptible alpha-hemolytic Streptococcal infections from January 2017 to December 2025.  Patients were included if they received parenteral-only therapy with ceftriaxone/vancomycin or oral transition therapy with cefpodoxime/cefdinir. Sterile cultures obtained from blood, fluid, and tissue were assessed. Patients were excluded if they had deep-seated and/or polymicrobial infections or were transitioned to comfort/hospice prior to treatment completion. The primary outcome was 90-day all-cause mortality. Secondary outcomes included recurrence of infection, hospital length of stay, and treatment-related adverse events. For analysis of continuous variables, the Student’s T-test or Mann-Whitney U Test were utilized and the Chi-square or Fisher’s exact test were conducted for categorical data. A total of 409 patients were screened. Of those, 43 were included in the IV group and 9 were included in the oral transition group. The gastrointestinal tract was the most common source of infection among both groups (42.3%) and most patients had secondary bacteremia (94.2%). No significant difference in all-cause mortality at 90-days was observed between the IV-only and oral transition therapy groups (9.3% vs. 11.1%; p = 1.00). In patients that received oral-transition therapy, the total duration of definitive therapy was significantly shorter (10 vs. 15 days; p < 0.01). The median hospital length of stay was significantly shorter in the oral-transition group (5 vs. 8 days, p < 0.05). No significant difference in adverse effects was observed between the groups. It remains unclear if there is a difference in all-cause mortality or recurrence of Streptococcal infections at 90 days between the IV-only and oral transition groups.  However, results suggest oral transition therapy with cefpodoxime and cefdinir may significantly reduce median hospital length of stay and total duration of definitive therapy.

Purpose: To compare the impact of polymerase chain reaction (PCR)-based and culture-based methicillin-resistant Staphylococcus aureus (MRSA) nasal swab testing on time to vancomycin de-escalation, test turnaround time, and cost-effectiveness.  
Methods: A multi-center, retrospective, observational pre-/post-implementation cohort study was conducted within two community hospitals in a large academic health system. The study evaluated hospitalized adults receiving empiric intravenous vancomycin for suspected pneumonia during March 1st to August 1st, 2024 (culture-based MRSA screening) and March 1st to August 1st, 2025 (MRSA nasal PCR screening). The primary outcome was time from MRSA screening test collection to vancomycin discontinuation. Secondary outcomes included test turnaround time, total vancomycin days of therapy, proportion of patients de-escalated within 36 hours, and rate of reinitiation of MRSA therapy during the admission. A cost analysis was also conducted.  
Results: Implementation of MRSA PCR testing significantly reduced the time from screening collection to vancomycin discontinuation. Median time decreased from 34.9 hours (IQR 25.8–51.0) pre-implementation to 18.8 hours (IQR 9.7–36.2) post-implementation (p < 0.001). Turnaround time was also significantly shorter with PCR (4.9 vs 28.3 hours, p < 0.001). While median total vancomycin days of therapy remained 2.0 days in both groups, the difference was still statistically significant (p = 0.004). De-escalation within 36 hours was numerically higher post-implementation (68% vs 51%, p = 0.132). 
Conclusions: Implementation of MRSA nasal PCR screening was associated with significantly faster test turnaround time and earlier discontinuation of vancomycin compared with culture-based screening. These findings support the use of rapid molecular diagnostics as a valuable tool in antimicrobial stewardship in the aim of timely de-escalation of empiric anti-MRSA therapy in patients with suspected or confirmed pneumonia.

Dual beta-lactam (DBL) regimens are leveraged for a variety of infections. Concerns regarding additive toxicity are prevalent despite limited evidence. This study aimed to describe the safety and tolerability of contemporary DBL regimens.


This was a retrospective single-arm cohort study including adult inpatients who received at least 72 hours of pre-specified DBL regimens from September 2021 to August 2025. Patients were excluded if any portion of a DBL course was given at an outside hospital. The primary outcome was the incidence of adverse drug events (ADEs) associated with DBL discontinuation. DBL discontinuation was defined as cessation of one or both beta-lactams due to a documented ADE. Secondary outcomes included time-to-ADE metrics and incidence of pre-specified ADE types (renal, neurologic, hepatobiliary, hematologic, hypersensitivity, or gastrointestinal). Causality was assessed using the WHO-UMC system with secondary adjudication by a co-investigator. Baseline characteristics and outcomes were analyzed using descriptive statistics. The Wilson Score method was used to calculate a 95% confidence interval (CI) for ADE incidence. 


A total of 175 patients were included. The most common DBL regimens were ceftriaxone plus ampicillin (52.0%) and cefepime plus ampicillin (21.7%). The most common DBL indications were E. faecalis synergy and empiric coverage of meningitis. A total of 124 patients (70.8%) had DBL therapy discontinued during admission. Only six discontinuations were associated with a documented ADE (3.4%; 95% CI, 1.6-7.3). Of these, only three were assigned a causality of possible or higher (1.7%; 95% CI, 0.6-4.9). These were leukopenia (n=2) and gastrointestinal intolerance (n=1), which resolved with DBL discontinuation. The median time to any ADE associated with DBL discontinuation was 6.5 days (IQR, 5.3-7.9). 


Treatment-limiting ADEs associated with contemporary DBL regimens were rare and reversible with discontinuation. These findings reinforce conclusions reported in prior literature. These results also suggest that clinicians’ perceived risk of DBL-related ADEs is likely to far exceed the actual risks associated with these regimens. Our findings support the use of DBL when clinically appropriate and in alignment with antimicrobial stewardship. 

Purpose: To evaluate real-world implementation of long-acting injectable cabotegravir (CAB)-based regimens for HIV treatment and Pre-Exposure Prophylaxis (PrEP) assessing adherence, retention, and outcomes.


Methods: This retrospective study evaluated patients initiating long-acting cabotegravir (CAB) based injectable therapy at Temple University Health System in Philadelphia, PA between FDA approval and September 1st 2025. Primary endpoints were adherence (defined by injections received within the FDA-approved ±7-day window) and retention in care. Secondary endpoints included continued viral suppression (HIV RNA <200 copies/mL) in the treatment group and all-cause discontinuation across both groups. Demographics, comorbidities, prior antiretroviral regimens, and associated laboratory values were collected.


Results: 200 patients received CAB/RPV for HIV treatment, median injections were 11 (5–16), and total injections given were 2121. 24 patients on CAB PrEP, median number of injections was 4.5 (3–11). In the treatment group, 45.5% of injections were within the ±7-day window; 67% required reinitiation (>30-day gaps). Overall, 72% remained on therapy. PrEP adherence was 79.2% within the window. At study end, 82.1% (46/56) of treatment discontinuations remained suppressed and 5.4% (3/56) had detectable HIV RNA; resistance occurred in 10.7% (6/56) of cases. Treatment discontinuation was 28%, driven by patient preference (28.6%) and

Purpose: To evaluate the likelihood of receiving guideline-concordant antimicrobial therapy among patients with S. pneumoniae bacteremia or pneumonia with and without a documented β-lactam allergy.
Methods: This retrospective cohort study included adults admitted to 3 academic medical centers in a single health system from January 2021 to May 2025 with S. pneumoniae bacteremia or pneumonia. Patients were identified via positive blood or respiratory cultures and included if ≥ 18 years old and received systemic antimicrobials. Exclusions were polymicrobial infections or infectious complications including empyema, endocarditis, bone/joint, or CNS. Patients were stratified by documented β-lactam allergy at admission (1:3 allergy to non-allergy). Data was collected using REDCap™. Patients were treated in accordance with institutional Antimicrobial Guidelines, ensuring therapy aligned with established recommendations. The primary outcome was the receipt of guideline-directed therapy, which was analyzed using the chi-square test. Secondary outcomes were summarized descriptively, and statistical significance was defined as a p-value<0.05.
Results: Of 64 patients, 16 (25%) had a documented β-lactam allergy. Guideline-concordant therapy was received by 12 (75.0%) with an allergy and 26 (54.2%) without. Patients with documented β-lactam allergy were more likely to receive guideline-directed therapy, but this difference was not statistically significant (χ² = 1.38, p = 0.24). Among cases of non-concordant therapy, the most common reason in patients with β-lactam allergy was prolonged duration (54.5%), switching to an oral fluoroquinolone (36.4%) and inappropriate oral therapy (9.1%). In patients without 

Purpose:
To evaluate early transition (at day 3 or less) compared to late transition (after day 3) of intravenous (IV) to oral (PO) antibiotics on clinical outcomes. 


Methods:
This study utilized retrospective chart review of patients treated for CAP within Lankenau Medical Center (LMC). Adult patients were included if they met CAP criteria published in the IDSA guidelines and received at least 3 days of antibiotic therapy. Patients were excluded if they did not meet criteria for transition to oral therapy in IDSA CAP guidelines, transferred from another inpatient facility, had concomitant infection treatment, or admitted to an intensive care unit on the day of antibiotic initiation. The primary outcome compared 30-day readmission rates between patients transitioned to PO before and after day 3 of antibiotics. Key secondary outcomes were compared between these groups and included 90-day all-cause mortality, hospital length of stay, total antibiotic days of treatment, and Clostridium difficile infection at day 90. 


Results:
676 patients were screened for meeting criteria, of which 50 met inclusion criteria. Six of these patients met early transition criterion, with 44 qualifying for late transition. Baseline characteristics across the two treatment groups were similar in Charlston Comorbidity Index and Pneumonia Severity Index scores. Thirty-day readmission occurred in 8 (18.2%) of the late transition group, with no readmissions in the early transition group. One patient within the late transition group did have mortality at 90 days, while no patients within the early transition group met this criterion. Both treatment groups had a median length of hospital stay of 5 days. 


Conclusion:
For patients meeting IDSA criteria, early transition to oral antibiotics in CAP patients was associated with decreased 30-day readmission rates as compared to late PO transition.

Purpose: Ideal timing of preoperative antibiotic administration in relation to incision time remains unclear. This study aims to evaluate optimal timing of preoperative antibiotic administration to mitigate the risk of surgical site infection (SSI).


Methods: This study was a retrospective, case-control trial evaluating 993 adult patients admitted to St. Luke’s University Health Network for a surgical procedure between January 2022 and December 2024. Patients were included at a 1:4 case-to-control, with cases defined as patients who developed a SSI, and controls defined as patients without subsequent SSI. Patients were excluded if they did not receive preoperative antibiotics, received preoperative antibiotics > 120 minutes prior to incision, underwent more than one procedure during index hospitalization, or had a preexisting infection at time and anatomical site of index procedure. The primary outcome was SSI rate by preoperative antibiotic administration time. Secondary outcomes included admission for SSI, hospital length of stay, readmission for SSI, and mortality at 30 and 90 days post-operation. SSIs were categorized based on National Healthcare Safety Network (NHSN) definitions.


Results: Cefazolin was the most frequent preoperative antibiotic administered (863 of 993 cases). Preoperative administration time was evaluated at 15-minute intervals, with time 0 being start of procedure. The SSI rate when cefazolin was administered before or at 45 minutes prior to procedure was significantly lower than the SSI rate when cefazolin was administered beyond 45 minutes (18.5% vs 44.4%, P = 0.005). The majority of patients presenting with a SSI were admitted for inpatient management (67.6%). In the subgroup analysis, cefazolin was associated with a significantly lower rate of SSIs compared to clindamycin (P = 0.013).


Conclusion: Cefazolin should be administered within 45 minutes of procedure initiation to best mitigate the risk of SSIs. Cefazolin was associated with a lower rate of SSIs compared to clindamycin, supporting its use as the preoperative antibiotic of choice.


IRB approval: yes 

Purpose:
This study evaluates the impact of reduced-dose amikacin liposome inhalation suspension (ALIS) on treatment outcomes in patients with pulmonary nontuberculous mycobacteria (NTM) infections who may experience treatment intolerance. 


Methods:
This was a retrospective, descriptive study. Eligible patients started ALIS therapy from September 1, 2018-June 30, 2024, and filled ALIS through the health system specialty pharmacy. Patients must have completed at least 6 months of ALIS therapy by June 30, 2025. Data was sourced through the pharmacy software system, and data collection was conducted through chart review. Patient adherence was quantified by a percentage of days covered (PDC), calculated based on refill history. The primary outcome was prevalence of negative cultures with various dosing strategies. Secondary outcomes included the incidence of culture reconversion up to one year after the first negative culture conversion or at the end of the study period, new culture resistance, number of patients with reduced ALIS dosing strategies, reasons for ALIS dose adjustments, and total duration of ALIS treatment.  Descriptive statistics were used to report outcomes. 


Results:
30 patients were included in this study and 17 (56%) were considered adherent to daily dosing based on a PDC of >80%. Overall, 24 (80%) patients achieved culture conversion, with 12 of 17 patients in the >80% PDC group and 12 of 13 in the <80% PDC group. Median time to culture conversion was 178.5 (117-216.5) days. Median time to culture conversion in the >80% PDC group was 201 (105-247.25) days vs.146 (122.5-210.75) days in the <80% PDC group. There were 12 (20%) patients with culture reconversion, with 6 of 17 patients in the >80% PDC group and 6 of 13 in the <80% PDC group. One patient (3.3%) developed new resistance to amikacin. There were several reasons for dose adjustment, with the most frequent reason being adverse effects. 


Conclusion:
Dose adjustments of ALIS did not appear to influence the rate of culture conversion in this study. There was a limited impact on resistance or duration of ALIS treatment. This suggests dose adjustment strategies may be an option for patients with adverse effects; however, further research is needed.

Purpose: Given the opportunity to optimize micafungin therapy in obese patients, our institution established a new protocol that recommends high doses for patients > 125 kg. We aimed to evaluate the outcomes associated with this new protocol.
 
Methods: This is a retrospective cohort study of patients at Thomas Jefferson University Hospital Inc locations from December 2024 to March 2026. Patients were included if they were 18 years or older, had documented invasive candidiasis, and received micafungin for 3 or more days. Patients were excluded if they had a concomitant infection within 7 days, were given empiric combination antifungal therapy, or had Candida species isolated from the genitourinary tract. Outcomes will be compared between patients weighing ≤ 125kg, patients weighing > 125kg on standard dose micafungin, and patients weighing > 125kg on high dose micafungin. The primary outcome is a composite of all–cause 90-day mortality, microbiologic and clinical cure, and incidence of recurrent infections within 30 days. The secondary outcomes are 30-day infection related readmission, duration of micafungin treatment, hospital and ICU length of stay and duration of candidemia.
 
Results: A total of 318 positive Candida cultures were identified and of those, 271 patients were removed to meet the exclusion criteria. Therefore, the study cohort included a total of 42 patients with 40 patients in the ≤ 125kg group, 1 patient in the > 125kg with standard micafungin dose group, and 1 patient in the > 125kg with high micafungin dose group. No difference was seen with the primary composite outcome between the cohorts (p=0.448). Due to low enrollment, exploratory analysis was performed utilizing binomial linear regression. When including mg/kg dosing as a continuous variable and analyzed it with other impactful and confounding variables, we did not find that it added significantly to the model. 
 
Conclusion: Our results from a very limited data set suggest that increased micafungin dosing in obese patients was not associated with improved clinical outcomes for invasive candidiasis. Exploratory analysis did not suggest that higher micafungin dosing (measured in mg/kg) provided additional benefit. Our institution will continue to collect data, in hopes of generating a greater sample size. Larger studies are required to confirm these results. 

Purpose: To implement a pharmacist-driven protocol which allows for the step-down of IV ceftriaxone to PO antibiotics for hospitalized patients with uncomplicated and complicated urinary tract infections to help improve transition time.  
Methods: A prospective study will be conducted from February 23, 2026 to May 12, 2026, using data collected from EPIC. The included patients will be age 18 and older with a UTI diagnosis, presence of stones, obstruction, strictures, TURP, prostatitis, stents, associated bacteremia, indwelling urinary catheters, pregnancy and before/after genitourinary procedure. Patients will be excluded if they have asymptomatic bacteriuria, secondary diagnosis for another infection, renal abscess, or are immunocompromised.  
The primary endpoint is transition time from IV to PO antibiotics. Secondary endpoints include length of stay, 30-day UTI readmission rates, total length of therapy, antibiotic selection and dosing. The endpoints will be compared to a retrospective analysis from May 1, 2025, to June 30, 2025, to assess if a pharmacist-driven protocol allowed for a timely transition to oral antibiotics and/or a reduction in any of the secondary endpoints.
Results: TBD 
Conclusion: TBD 
IRB Approval: IRB approval is not required as this research is categorized as a process improvement project.  

Purpose: Despite structural dissimilarity between penicillins and piperacillin/tazobactam (P/T), the incidence of cross-reactivity is unknown. This project evaluated the incidence of P/T reaction in patients with documented β-lactam reactions.


Methods: This was a retrospective single-center cohort analysis evaluating patients with reported β-lactam reactions who received P/T from July 2022 to June 2025. Patients were included if they received at least one dose of P/T during this time and had a previously reported β-lactam reaction. Patients were excluded if they were less than 18 years old, the P/T order was not administered, or there was insufficient quality of data. The primary outcome was the compared incidence of P/T reactions between patients with documented penicillin class reactions versus patients with reactions to all other β-lactams and β-lactamase inhibitors. Secondary outcomes were the incidence of P/T reactions in the following subgroups: subclass of previous β-lactam reaction, previous reaction type classification, P/T duration, and number of previously reported reactions. Results were analyzed using a Chi-squared analysis and descriptive statistics.


Results: Of 183 patients screened for analysis, 164 were included. Previously reported β-lactam reactions were classified as IgE-mediated (30%), non-IgE-mediated (18%), adverse reactions (23%), and unknown (29%). There were 21 (13%) patients with multiple β-lactam allergies. Potential reaction to P/T occurred in 0/87 (0%) patients with penicillin class reactions and 1/77 (1.3%) patients with non-penicillin β-lactam reactions (p=0.286). The patient with a documented reaction to P/T had a history of developing hives to cefuroxime. The median [IQR] length of treatment for patients who received multiple doses in an encounter was 2 [1-3.5] days, with the most common reason for discontinuation being targeted antimicrobial therapy (47%). 


Conclusion: In patients labeled with a β-lactam reaction, there was minimal incidence of P/T reactions, with 1/164 patients (0.6%) experiencing a documented reaction. These results support the hypothesis that cross-reactivity would be low based on structural dissimilarity, including penicillin class allergies. Further research is warranted to further elucidate the safety of administering P/T in this patient population.

Purpose: 
The aim of this study was to evaluate the impact of albumin status on clinical and microbiological outcomes of patients treated with ertapenem or meropenem for ESBL-E bacteremia, and to identify factors associated with treatment failure.
 
Methods:
We conducted a dual-center, retrospective cohort study of adult patients admitted between October 1, 2022, and October 1, 2025, who received ertapenem or meropenem for the treatment of ESBL-E bacteremia (ceftriaxone-resistant Escherichia coli, Klebsiella spp. (non-aerogenes), or Proteus spp.). Patients were stratified by albumin status (L-Alb: serum albumin < 2.5 mg/dL or N-Alb: serum albumin ≥ 2.5 mg/dL) and carbapenem selection. The primary outcome was a composite of treatment failure: death, readmission for related infectious causes, recurrent infection, or absence of clinical improvement by day 14. Secondary outcomes included 30-day all-cause mortality and evaluation of clinical characteristics hypothesized to be associated with treatment failure. Categorical variables were compared using chi-square or Fisher’s exact tests. A multivariable logistic regression was performed to identify factors independently associated with outcomes.
 
Results: 
Among 203 patients with a median age of 63 years, 23.6% had L-Alb, and 49.8% were immunocompromised. Bacteremia was primarily caused by E. coli (57.6%) from urinary or intra-abdominal sources, and the 30-day all-cause mortality rate was 14.3%. The primary outcome occurred in 24.6% of the cohort. Treatment failure was higher in patients with L-Alb versus N-Alb (47.9% vs 17.4%, P < 0.01) and with ertapenem in relation to albumin status (42.3% vs 12.9%, P < 0.01), but not with meropenem (54.5% vs 35.5%, P = 0.17). On multivariable analysis, L‑Alb (OR 2.76, 95% CI [1.26-6.04]) and lack of source control (OR 4.45, 95% CI [1.77-11.22]) independently predicted treatment failure, while ertapenem did not appear to (OR 0.42, 95% CI [0.19–0.93]).
 
Conclusion: 
Our study presents medically complex patients with ESBL-E bacteremia not limited by infectious source. While prior literature cautions against ertapenem in patients who are critically ill and/or with L-Alb, our data suggests that poor ertapenem efficacy is multifactorial. Although failure rates were higher in patients with L-Alb receiving ertapenem, ertapenem did not appear to be associated with increased failure after adjusting for confounders.
 

Objective: The purpose of this study was to evaluate the impact of a pharmacist-driven antimicrobial stewardship (ASP) initiative using rapid diagnostic testing (RDT) on de-escalation of antipseudomonal antibiotic therapy for Enterobacterales bloodstream infections (BSIs).  
Methods: This was a multi-center, retrospective, comparative cohort study was approved by the institutional review board review (IRB) and included a sample of adult patients with Enterobacterales bacteremia who received empiric antipseudomonal therapy. Treatment was compared pre- and post- implementation of RDT. The primary outcome was time (hours) to de-escalation of antipseudomonal coverage. Secondary outcomes included days of antipseudomonal antibiotic therapy, 30-day mortality, and incidence of Clostridioides difficile infection (CDI). A subgroup analysis was also conducted to evaluate the use of anti-methicillin resistant Staphylococcus aureus (MRSA) therapy. Antimicrobial stewardship activities were also evaluated in the post-implementation group. 
Results: This study included 44 patients in the pre-implementation group and 60 patients in the post-implementation group. Baseline characteristics were comparable between both groups. The median time (hours) to de-escalation of antipseudomonal coverage for Enterobacterales bacteremia was found to be significantly lower in the post-implementation group (9.3 vs 50.5, p < 0.001). Median days of therapy was also found to be lower in the post-implementation group (2 vs 4 days, p < 0.001). The 30-day mortality rate, CDI events, and days of anti-MRSA therapy were not statistically different between groups. 
Conclusion: This study demonstrated that a pharmacist-driven antimicrobial stewardship initiative was successful in reducing time to targeted therapy in hospitalized patients receiving treatment for Enterobacterales bacteremia.