We evaluated the Xpert MTB/Rif Ultra assay performance for Mycobacterium tuberculosis (MTB) detection in formalin-fixed paraffin-embedded tissue (FFPET) compared to mycobacterial culture or laboratory-developed MTB PCR test (LDT). FFPET samples with histological features suggestive of tuberculosis from 2018 to 2023 were selected. Five hundred microlitres of tissue lysis buffer was added to FFPET scrolls and incubated at 75 °C for 5 min. After adding 50 µl of proteinase K and overnight incubation at 56 °C, sample aliquots were processed as per the manufacturer’s instructions. MTB culture or LDT assay results were used as a reference for sensitivity and specificity calculations. Of 51 eligible FFPET, 32 were positive for MTB either by culture or LDT PCR on FFPET. Xpert MTB/Rif Ultra detected MTB in 23/32 positive specimens [71.9%, 95% confidence interval (CI) 54.6–84.4%]. Of nine discordant specimens, seven were MTB positive by culture and two were identified by LDT MTB PCR only, as no specimen was submitted for MTB culture. Of 19 negative samples, 100% specificity (95% CI 83.2–100.0%) was attained via Xpert MTB/Rif Ultra. Implementation of Xpert MTB/Rif Ultra on FFPET within clinical laboratories is promising, given its improved turnaround time compared to MTB culture and ability to detect MTB in cases where no tissue is available for culture.

Background: Investigating antibody titers in individuals who have been both naturally infected with SARS-CoV-2 and vaccinated can provide insight into antibody dynamics and correlates of protection over time. Methods: Human coronavirus (HCoV) IgG antibodies were measured longitudinally in a prospective cohort of qPCR-confirmed, COVID-19 recovered individuals (k = 57) in British Columbia pre- and post-vaccination. SARS-CoV-2 and endemic HCoV antibodies were measured in serum collected between Nov. 2020 and Sept. 2021 (n = 341). Primary analysis used a linear mixed-effects model to understand the effect of single dose vaccination on antibody concentrations adjusting for biological sex, age, time from infection and vaccination. Secondary analysis investigated the cumulative incidence of high SARS-CoV-2 anti-spike IgG seroreactivity equal to or greater than 5.5 log10 AU/mL up to 105 days post-vaccination. No re-infections were detected in vaccinated participants, post-vaccination by qPCR performed on self-collected nasopharyngeal specimens. Results: Bivariate analysis (complete data for 42 participants, 270 samples over 472 days) found SARS-CoV-2 spike and RBD antibodies increased 14–56 days post-vaccination (p < 0.001) and vaccination prevented waning (regression coefficient, B = 1.66 [95%CI: 1.45–3.46]); while decline of nucleocapsid antibodies over time was observed (regression coefficient, B = −0.24 [95%CI: −1.2-(−0.12)]). A positive association was found between COVID-19 vaccination and endemic human β-coronavirus IgG titer 14–56 days post vaccination (OC43, p = 0.02 & HKU1, p = 0.02). On average, SARS-CoV-2 anti-spike IgG concentration increased in participants who received one vaccine dose by 2.06 log10 AU/mL (95%CI: 1.45–3.46) adjusting for age, biological sex, and time since infection. Cumulative incidence of high SARS-CoV-2 spike antibodies (>5.5 log10 AU/mL) was 83% greater in vaccinated compared to unvaccinated individuals. Conclusions: Our study confirms that vaccination post-SARS-CoV-2 infection provides multiple benefits, such as increasing anti-spike IgG titers and preventing decay up to 85 days post-vaccination.

Introduction. Systemic human infections caused by Erysipelothrix rhusiopathiae have been increasingly reported especially within immunocompromised hosts and those with significant occupational exposure to livestock and aquatic animals. We report a case of E. rhusiopathiae bacteraemia in a patient with systemic lupus erythematosus (SLE) and present a literature review on clinical outcomes and microbiologic diagnosis for this organism. Case presentation. A 43-year-old female patient was reporting a 1-month history of intermittent fevers. She recently increased her immunosuppression medication for her underlying SLE on the advice of her rheumatologist. The patient sustained a finger laceration from butchering cattle meat 2 weeks after the onset of her initial symptoms, with worsening index finger swelling and increased febrile episodes. Two weeks post-injury, multiple blood cultures were drawn, and each isolated Gram-positive bacilli. Given her recurrent intermittent fevers, there was a concern for ongoing infection, and therefore, intravenous vancomycin was started with prompt referral to an outpatient parenteral antibiotic therapy clinic. The Gram-positive bacillus was confirmed as E. rhusiopathiae via matrix-assisted laser desorption/ionization-time of flight analysis. Given intrinsic resistance to vancomycin, vancomycin was switched to intravenous ceftriaxone as targeted antimicrobial therapy for 2 weeks. Reassuringly, there was no echocardiographic evidence of infective endocarditis, warranting the prolonged treatment course. Post-treatment, she remained symptom-free with the resolution of joint symptoms and fevers. Conclusion. Our report illustrates a case of E. rhusiopathiae bacteraemia from an immunodeficient host, with prompt microbiologic diagnosis and intervention with appropriate antimicrobial coverage. Literature reflects the rarity of this infection, predilections to specific susceptible hosts and the importance of raising awareness of zoonotic infections.

Klebsiella variicola (K. variicola) is a Gram-negative organism genetically similar to Klebsiella pneumoniae (K. pneumoniae) that can cause a variety of diseases in humans. Bacteremia due to K. variicola is associated with a higher mortality rate than bacteremia with K. pneumoniae. Here, we describe a 65-year-old woman who developed pyelonephritis 2 months after receiving a renal transplantation following a longstanding history of end-stage renal disease secondary to polycystic kidney disease. Her creatinine on admission was unchanged from her posttransplant baseline, and an abdominal CT scan showed inflammatory changes around the transplanted kidney that were suggestive of an infection rather than allograft rejection. She was initially treated empirically with meropenem given a history of extended-spectrum beta-lactamase- (ESBL-) producing E. coli bacteriuria. After a day of therapy with meropenem, her therapy was streamlined based on culture results to ceftriaxone. She continued to improve, her kidney function remained stable, and she was prescribed oral ciprofloxacin to complete a 14-day total course of antibiotics. This case is the first reported instance of K. variicola bacteremia associated with pyelonephritis in a renal transplant recipient. Hospitalization with acute pyelonephritis within the first year following kidney transplant is common and is associated with increased risk of graft loss and mortality. However, K. variicola is not a commonly known organism to cause this infection. Despite the risk of allograft failure in this circumstance, this patient was successfully treated with a 14-day course of antibiotic therapy.

We report the case of an extremely preterm neonate (23 + 4 weeks, 486 g) whose mother had a history of multidrug-resistant infections during pregnancy, and who developed multidrug-resistant Klebsiella sepsis, meningitis and subsequent pneumonia. Cefiderocol was used to successfully treat the infections with no known adverse effects. The neonate was discharged home at 51 + 1 weeks.

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.