Background: Erroneously labeled penicillin allergies can lead to prolonged hospitalization, increased adverse effects and infection rates with alternative antibiotics. Although elderly patients are more vulnerable to these negative outcomes, penicillin allergy assessments and de-labeling remain underutilized in this population. Objective: To assess the efficacy and challenges of implementing penicillin allergy de-labeling in hospitalized elderly patients. Methods: Between March 2024 and April 2025, we conducted a quality improvement study on patients who were 65 years and older, had a penicillin allergy, and were admitted to Burnaby Hospital Acute Care for Elderly (ACE) Unit. Patients were proactively screened, interviewed, and assessed for eligibility in allergy de-labeling based on PEN-FAST score ≤1, predefined criteria, clinical judgment, and patient consent. If penicillin challenge was given, patients received pharmacist follow-up and 4-week outcomes were documented. A post-implementation survey was distributed to ward healthcare staff to identify barriers to implementation. Results: Out of 105 patients screened, 87 patients met study inclusion criteria. Among 34 patients deemed eligible for de-labeling, 24 patients (71%) were de-labeled from either oral amoxicillin challenge or information gathering alone. Within four weeks after de-labeling, 10 patients (42%) received beta-lactam antibiotics, and no patients received guideline-discordant broad-spectrum antibiotics. Only 1 patient experienced a delayed reaction to amoxicillin-clavulanate. From surveying ACE unit nursing, physician, and pharmacy staff, frequently reported barriers to allergy assessment and de-labeling included time and staffing constraints, and patient complexity. Conclusions: Our pharmacy-driven interdisciplinary penicillin allergy de-labeling initiative is effective and safe for eligible hospitalized older adults with low PEN-FAST scores (≤1).

Background: From 2018 to 2021, travel-related extensively drug-resistant (XDR) Salmonella Typhi was identified in Ontario, Canada. Opportunities remain to characterize typhoidal Salmonella antimicrobial susceptibility trends (including multi-drug resistance phenotypes; MDR) within a large health authority in British Columbia, Canada. Methods: This retrospective study included patients with Salmonella Typhi or Paratyphi A, B or C bacteremia identified at Fraser Health regional microbiology laboratory from 2018 to 2024. The primary outcome was the proportion of cases with MDR and XDR typhoidal Salmonella. Secondary outcomes included annual antimicrobial susceptibility for ampicillin, ceftriaxone, ciprofloxacin, trimethoprim-sulfamethoxazole, ertapenem, meropenem and azithromycin. Clinical outcomes included hospitalization length, and 30-day mortality, clinical cure and infection relapse. Results: Among 271 patients, most were previously healthy and recently travelled. There were extended spectrum beta-lactamase (1.1%) and MDR (1.5%) typhoidal Salmonella, with no XDR cases observed. In 2024, ciprofloxacin resistance was 96% while susceptibility rates were high for other studied antimicrobials. Within 30 days, no deaths were reported; however, six patients (3%) had infection relapse. Conclusions: Currently, in British Columbia, MDR typhoidal Salmonella remains rare. Empiric ciprofloxacin should be avoided due to persistently high resistance rates. With ongoing travel patterns, it is beneficial for institutions to continue typhoidal Salmonella antimicrobial susceptibility surveillance, and travelers should seek pre-travel health assessments.

Introduction. Despite the established pathogenicity of Aggregatibacter aphrophilus , few clinical cases have been described in published literature. A. aphrophilus is a rare cause of prosthetic valve endocarditis and diagnosis is challenging based on nonspecific symptoms on presentation. High clinical suspicion for infective endocarditis is warranted in patients with cardiac prosthetic material and positive blood cultures. Poor dentition and dental procedures, along with other risk factors, are associated with A. aphrophilus bacteraemia. We describe a case of A. aphrophilus bacteraemia in which the diagnosis of infective endocarditis was complicated by equivocal echocardiographic findings and an initially challenging Gram stain interpretation. Case Presentation. A 59-year-old male patient with a history of bioprosthetic aortic valve replacement, atrial septal defect repair and remote dental cleaning presented to the emergency department with persistent high fevers, headaches and lethargy. Initial blood cultures were drawn and were positive for ‘Gram-positive organisms’, but specific morphology was challenging to determine. Subsequent testing, including MALDI-TOF, confirmed the growth of A. aphrophilus . Conclusion. Rapid identification of A. aphrophilus and recognition of the potential for infective endocarditis are paramount to ensuring adequate treatment initiation and success. This case highlights the diagnostic difficulty associated with initial Gram stain interpretation of this fastidious organism.

2. Abstract Introduction Despite the established pathogenicity of Aggregatibacter aphrophilus, few clinical cases have been described in published literature. A. aphrophilus is a rare cause of prosthetic valve endocarditis and diagnosis is challenging based on nonspecific symptoms on presentation. High clinical suspicion for infective endocarditis is warranted in patients with cardiac prosthetic material and positive blood cultures. Poor dentition and dental procedures, along with other risk factors, are associated with A. aphrophilus bacteremia. We describe a case of A. aphrophilus bacteremia in which the diagnosis of infective endocarditis was complicated by equivocal echocardiographic findings and an initially challenging Gram stain interpretation. Case Presentation A 59-year-old male patient with history of bioprosthetic aortic valve replacement, atrial septal defect repair, and remote dental cleaning presented to the emergency department with persistent high fevers, headaches, and lethargy. Initial blood cultures were drawn and were positive for “gram-positive organisms”, but specific morphology was challenging to determine. Subsequent testing, including MALDI-TOF, confirmed the growth of Aggregatibacter aphrophilus. Conclusion Rapid identification of A. aphrophilus and recognition of the potential for infective endocarditis are paramount to ensuring adequate treatment initiation and success. This case highlights the diagnostic difficulty associated with initial Gram stain interpretation of this fastidious organism.

2. Abstract Introduction Despite the established pathogenicity of Aggregatibacter aphrophilus, few clinical cases have been described in published literature. A. aphrophilus is a rare cause of prosthetic valve endocarditis and diagnosis is challenging based on nonspecific symptoms on presentation. High clinical suspicion for infective endocarditis is warranted in patients with cardiac prosthetic material and positive blood cultures. Poor dentition and dental procedures, along with other risk factors, are possible mechanisms by which A. aphrophilus gains entry into the bloodstream. Case Presentation A 59-year-old male patient with history of bioprosthetic aortic valve replacement, atrial septal defect repair and remote dental cleaning presented to the emergency department with persistent high fevers, headaches, and lethargy. Initial blood cultures were drawn and were positive for “Gram-positive organisms”, but specific morphology was challenging to determine. Subsequent testing, including MALDI-TOF, confirmed the growth of Aggregatibacter aphrophilus. Conclusion Rapid identification of A. aphrophilus and diagnosis of infective endocarditis is paramount to ensuring adequate treatment initiation and success.

Background: From 2018-2021, travel-related extensively drug-resistant (XDR) Salmonella Typhi was identified in Ontario, Canada. There remain opportunities to characterize typhoidal Salmonella antimicrobial susceptibility trends within a large health authority in British Columbia, Canada. Methods: This retrospective study included patients with Salmonella Typhi or Paratyphi A, B or C bacteremia identified at Fraser Health regional microbiology laboratory from 2018-2024. Primary outcome was proportion of cases with multi-drug resistant (MDR) and XDR typhoidal Salmonella. Secondary outcomes included annual antimicrobial susceptibility for ampicillin, ceftriaxone, ciprofloxacin, trimethoprim-sulfamethoxazole, ertapenem, meropenem and azithromycin. Clinical outcomes included hospitalization length, and 30-day mortality, clinical cure and infection relapse. Results: Among 271 patients, most were previously healthy and recently travelled. There were extended spectrum beta-lactamase (1.1%) and MDR (1.5%) typhoidal Salmonella, with no XDR cases observed. In 2024, ciprofloxacin resistance was 96% while susceptibility rates were high for other studied antimicrobials. Within 30 days, no deaths were reported; however, 6 patients (3%) had infection relapse. Conclusion: Currently in British Columbia, MDR typhoidal Salmonella remains rare. Empiric ciprofloxacin should be avoided due to persistently high resistance rates. With ongoing travel patterns, it is beneficial for institutions to continue typhoidal Salmonella antimicrobial susceptibility surveillance, and travelers should seek pre-travel health assessments.