Emma Finlayson-Trick

Background: Hypervirulent Klebsiella pneumoniae (hvKp) is poorly characterized in North America and likely underrecognized. We evaluated a molecular screening approach for hvKp and described the clinical, microbiological, and genomic characteristics of hvKp isolates in Vancouver, Canada. Method: We conducted a retrospective study of sterile-site Kp isolates recovered at a tertiary care center (2018–2024). Archived isolates were screened using polymerase chain reaction (PCR) targeting peg-344 and iucA. Whole-genome sequencing was then performed, with hvKp defined as a Kleborate virulence score of ≥3. Clinical data were obtained through chart review. Genomic relatedness was assessed using reference-based multilocus sequence typing. Results: Among 449 isolates, 43 were PCR positive for peg-344 and/or iucA, and 38 met criteria for hvKp. Only 5 (13%) cases were suspected at the time of isolation. The molecular screen demonstrated 100% sensitivity and 98.8% specificity for hvKp detection. Compared with classical Kp, hvKp infection was independently associated with travel history (adjusted odds ratio [aOR], 9.73; 95% CI, 2.06–46.04) and residence in Vancouver's Downtown Eastside (DTES; aOR, 3.69; 95% CI, 1.05–12.97), but not with Indo-Pacific country of origin (aOR, 1.77; 95% CI, .49–6.37). Genomic analysis suggested possible local transmission between 2 DTES patients. K1/K2 were the most common capsular serotypes. One ST15 hvKp isolate carried blaNDM, representing a convergent hypervirulent and carbapenem-resistant strain. Conclusions: Routine molecular screening improved detection of hvKp and revealed evolving epidemiology, including possible clonal transmission. Implementing laboratory-based molecular screening can enhance clinical recognition, guide evaluation for metastatic complications, and monitor the emergence of high-risk strains.

Early detection of Klebsiella pneumoniae carbapenemase (KPC)-producing Enterobacterales enables prompt initiation of appropriate antimicrobial therapy and infection prevention and control measures. The matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) Biotyper (MBT) Subtyping Module (Bruker Daltonics) uses a characteristic spectral peak at ~11,109 m/z to identify KPC-producing Enterobacterales . The aim of this study was to assess the ability of the MBT Module to detect KPC among a variety of clinical and reference (AR Bank) Enterobacterales isolates. Detection of KPC was compared between the MBT Module and a laboratory-developed real-time KPC PCR. Of the 93 isolates tested, 58 (62.4%) were positive for KPC by PCR (39 clinical and 19 AR bank isolates), and 35 were negative. Among the KPC-positive PCR isolates, nine (seven clinical and two AR bank) also tested positive for KPC by the MBT Module. KPC detection via the MBT Module had a sensitivity of 15.5% and a specificity and positive predictive value of 100%. This study also assessed the performance of the MBT Module to detect KPC-2 versus KPC-3 among the AR Bank isolates. The MBT Module detected 2/5 (40.0%) KPC-2 and 0/14 of KPC-3 AR Bank isolates. As sensitivity was low, but specificity was high, a positive MBT Module result reliably predicts the presence of KPC; however, negative results cannot be relied upon to be truly KPC-negative. IMPORTANCE: Enterobacterales , a large order of pathogenic and commensal bacteria, can gain resistance to carbapenems through the acquisition of plasmids carrying genes, such as Klebsiella pneumoniae carbapenemase (KPC). Early detection of KPC is crucial for patient care; however, current detection methods that involve multiple time-consuming steps, commonly only undertaken after overnight susceptibility testing, indicate possible carbapenem resistance. This study examined the ability of matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF), a common diagnostic tool in the clinical laboratory, to detect KPC among Enterobacterales . KPC detection via MALDI-ToF had low sensitivity but 100% specificity. These results support and expand the microbiological and geographical range of prior publications for this tool. A practical application of this highly specific method would involve rapid triaging of KPC-positive isolates a day earlier than current methods, permitting initiation of more timely therapeutic and infection prevention and control measures.

Introduction: The COVID‐19 pandemic has changed healthcare service delivery. We examined the overall impact of COVID‐19 on people living with HIV in British Columbia (BC), Canada, with a special focus on the potential impact of COVID‐19 on antiretroviral treatment interruptions (TIs).Methods: Purposive sampling was used to enrol people living with HIV aged ≥19 years across BC into the STOP HIV/AIDS Program Evaluation study between January 2016 and September 2018. Participants completed surveys at baseline enrolment and 18 and 36 months later. Additional COVID‐19 questions were added to the survey in October 2020. TIs were defined as >60 days late for antiretroviral therapy (ART) refill using data from the BC HIV Drug Treatment Program. Generalized linear mixed models were used to examine trends in TIs over time and associations with reported health service access.Results: Of 581 participants, 6.1%–7.7% experienced a TI during each 6‐month period between March 2019 and August 2021. The frequency of TIs did not statistically increase during the COVID‐19 epidemic. Among the 188 participants who completed the COVID‐19 questionnaire, 32.8% reported difficulty accessing healthcare during COVID‐19, 9.7% reported avoiding continuing a healthcare service due to COVID‐19‐related concerns, and 74.6% reported using virtual healthcare services since March 2020. In multivariable analysis, the odds of a TI in any 6‐month period were not significantly different from March to August 2019. None of the reported challenges to healthcare services were associated with TIs.Conclusions: Although some participants reported challenges to accessing services or avoidance of services due to COVID‐19, TIs were not more likely during COVID‐19 than before.

To the best of our knowledge, this is the first published study to characterize the effects of oral iron supplementation on the gut microbiomes of Cambodian WRA. Our study found that iron supplementation with ferrous bisglycinate increases the relative abundance of Enterobacteriaceae , which is a family of bacteria that includes many Gram-negative enteric pathogens like Salmonella , Shigella , and Escherichia coli .

Iron supplementation and fortification are used to treat iron deficiency, which is often associated with gastrointestinal conditions, such as inflammatory bowel disease and colorectal cancer. Within the gut, commensal bacteria contribute to maintaining systemic iron homeostasis. Disturbances that lead to excess iron promote the replication and virulence of enteric pathogens. Consequently, research has been interested in better understanding the effects of iron supplementation and fortification on gut bacterial composition and overall gut health. While animal and human trials have shown seemingly conflicting results, these studies emphasize how numerous factors influence gut microbial composition. Understanding how different iron formulations and doses impact specific bacteria will improve the outcomes of iron supplementation and fortification in humans. Furthermore, discerning the nuances of iron supplementation and fortification will benefit subpopulations that currently do not respond well to treatment.

Heat shock proteins (HSPs) are essential mediators of cellular homeostasis by maintaining protein functionality and stability, and activating appropriate immune cells. HSP activity is influenced by a variety of factors including diet, microbial stimuli, environment and host immunity. The overexpression and down-regulation of HSPs is associated with various disease phenotypes, including the inflammatory bowel diseases (IBD) such as Crohn’s disease (CD). While the precise etiology of CD remains unclear, many of the putative triggers also influence HSP activity. The development of different CD phenotypes therefore may be a result of the disease-modifying behavior of the environmentally-regulated HSPs. Understanding the role of bacterial and endogenous HSPs in host homeostasis and disease will help elucidate the complex interplay of factors. Furthermore, discerning the function of HSPs in CD may lead to therapeutic developments that better reflect and respond to the gut environment.

Plant cell walls are comprised of cellulose, hemicellulose, and lignin, collectively known as lignocellulose. Microorganisms degrade these components to liberate sugars to meet metabolic demands. Using a metagenomic sequencing approach, we previously demonstrated that the microbiome of the North American porcupine ( Erethizon dorsatum ) is replete with novel lignocellulose-degrading enzymes. Here, we report the identification, synthesis and partial characterization of four genes from the porcupine microbiome encoding putative novel lignocellulose-degrading enzymes, including a β-xylanase, endoxylanase, β-glucosidase, and an ⍺-L-arabinofuranosidase. These genes were identified via conserved catalytic domains associated with cellulose and hemicellulose degradation. We cloned the putative β-xylanase into the pET26b(+) plasmid, enabling inducible gene expression in Escherichia coli ( E. coli ) and periplasmic localization. We demonstrated IPTG-inducible accumulation of β-xylanase protein but failed to detect xylobiose degrading activity in a reporter assay. Alternative assays may be required to measure activity of this putative β-xylanase. In this report, we describe how a synthetic metagenomic pipeline can be used to identify novel microbial lignocellulose-degrading enzymes and take initial steps to introduce a hemicellulose-degradation pathway into E. coli to enable biofuel production from wood pulp feedstock.