Publications by authors named "Larissa M Matukas"

Background: Point-of-care testing (POCT) is increasingly being used in healthcare, including hospitals, and POCT-style tests are also used within some laboratories. The principles of biosafety, including risk assessment and containment of biohazardous agents, can be utilized as a foundation to establish policies and procedures guiding safe performance of POCT. However, specific biosafety guidelines for POCT are generally lacking, particularly for those performed outside laboratories by healthcare workers.

View Article and Find Full Text PDF

Current guideline recommends the use of two identification methods for Neisseria gonorrhoeae. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) is now used for primary identification and may be sufficient for definitive identification of N. gonorrhoeae.

View Article and Find Full Text PDF

Background: In 2022, the global dissemination of mpox virus (MPXV) outside endemic regions prompted the expansion of diagnostic testing worldwide. This study assesses the performance characteristics of 5 real-time polymerase chain reaction (PCR) assays in detecting MPXV during the 2022 outbreak.

Methods: Clinical specimens collected from patients across Ontario, Canada, were tested on the following assays: RealStar Orthopoxyvirus PCR and FlexStar Monkeypox virus PCR (Altona Diagnostics), Novaplex MPXV (Seegene), VIASURE Monkeypox virus Real Time PCR Reagents (CerTest Biotec), and a laboratory-developed test.

View Article and Find Full Text PDF

Widespread and frequent testing for COVID-19 was an important strategy to identify infected patients to isolate and control the spread of the disease during the pandemic. The nasopharyngeal swab (NPS) global supply chain and access to trained healthcare professionals for standard NPS collection were often compromised. Patient discomfort and limited access challenged health systems to reach large numbers for testing in adult and pediatric populations.

View Article and Find Full Text PDF

Superficial skin swab collections are inherently low-quality and may be of little clinical value due to their poor sensitivity and specificity. Clinical microbiology laboratories can use Gram smears to screen and differentiate higher and lower quality specimens to direct the extent of potential pathogen work up, including antimicrobial susceptibility testing (AST). We compared the impact of two different smear grading approaches to our current reporting practices for superficial wound swab cultures.

View Article and Find Full Text PDF

The emergence of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV-2) was met with rapid development of robust molecular-based detection assays. Many SARS-CoV-2 molecular tests target multiple genetic regions of the virus to maximize detection and protect against diagnostic escape. Despite the relatively moderate mutational rate of SARS-CoV-2, numerous mutations with known negative impact on diagnostic assays have been identified.

View Article and Find Full Text PDF

The IR Biotyper and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) using ClinProTools software (MALDI-TOF MS-ClinProTools) are two novel typing methods that rely on the analysis of carbohydrate and peptide residues in intact bacterial cells. These two methods have shown promising results in the rapid and accurate typing of bacteria. In this study, we evaluated these novel typing methods in comparison with genotypic typing for cluster analysis of Burkholderia cenocepacia epidemic strain ET12, isolated from adult cystic fibrosis patients.

View Article and Find Full Text PDF

Background: The role of antibiotics in preventing urinary tract infection (UTI) in older adults is unknown. We sought to quantify the benefits and risks of antibiotic prophylaxis among older adults.

Methods: We conducted a matched cohort study comparing older adults (≥66 years) receiving antibiotic prophylaxis, defined as antibiotic treatment for ≥30 days starting within 30 days of a positive culture, with patients with positive urine cultures who received antibiotic treatment but did not receive prophylaxis.

View Article and Find Full Text PDF

Objective: Selective reporting of antibiotic susceptibility test results may help guide appropriate antibiotic prescribing, particularly for urinary tract infections. Our objective was to describe laboratory urine culture susceptibility reporting practices and to estimate their impact on antibiotic prescribing in outpatients.

Methods: We examined all positive urine cultures with Escherichia coli, Klebsiella pneumoniae, or Proteus mirabilis associated with an antibiotic prescription among outpatients over 65 years of age in Ontario, Canada from 2014 through 2017.

View Article and Find Full Text PDF

Rationale & Objective: Hemodialysis patients are at increased risk for coronavirus disease 2019 (COVID-19) transmission due in part to difficulty maintaining physical distancing. Our hemodialysis unit experienced a COVID-19 outbreak despite following symptom-based screening guidelines. We describe the course of the COVID-19 outbreak and the infection control measures taken for mitigation.

View Article and Find Full Text PDF

Background: Timely strain typing of group A (GAS) is necessary to guide outbreak recognition and investigation. We evaluated the use of (matrix-assisted laser desorption ionization time-of-flight mass spectrometry) combined with cluster analysis software to rapidly distinguish between related and unrelated GAS isolates in real-time.

Methods: We developed and validated a typing model using 177 GAS isolates with known types.

View Article and Find Full Text PDF

Background: Nudging in microbiology is an antimicrobial stewardship strategy to influence decision making through the strategic reporting of microbiology results while preserving prescriber autonomy. The purpose of this scoping review was to identify the evidence that demonstrates the effectiveness of nudging strategies in susceptibility result reporting to improve antimicrobial use.

Methods: A search for studies in Ovid MEDLINE, Embase, PsycINFO, and All EBM Reviews was conducted.

View Article and Find Full Text PDF

We evaluated a direct from positive blood culture pelleting procedure that utilizes a lysis-centrifugation protocol for the identification of microorganisms by MALDI-TOF MS with subsequent antimicrobial susceptibility testing (AST) and rapid methicillin- and beta-lactam-resistance screening. The identification evaluation was performed on 125 cultures and resulted in the correct genus-level identification in 91.2% of cultures and a species-level concordance of 82.

View Article and Find Full Text PDF

Objective: To assess the clinical findings and microbiology investigations in patients with suspected infectious posterior segment uveitis (PSU).

Design: Retrospective case study.

Methods: Between January and December 2014, medical records of 270 patients with PSU were reviewed.

View Article and Find Full Text PDF

This document outlines a comprehensive practical approach to a laboratory quality management system (QMS) by describing how to operationalize the management and technical requirements described in the ISO 15189 international standard. It provides a crosswalk of the ISO requirements for quality and competence for medical laboratories to the 12 quality system essentials delineated by the Clinical and Laboratory Standards Institute. The quality principles are organized under three main categories: quality infrastructure, laboratory operations, and quality assurance and continual improvement.

View Article and Find Full Text PDF

Cumulative susceptibility test data (CSTD) are used to guide empirical antimicrobial therapy and to track trends in antibiotic resistance. The Clinical and Laboratory Standards Institute recommends reporting CSTD at least annually and sets the minimum number of isolates per reported organism at 30. To comply, many hospitals combine data from multiple intensive care units (ICUs); however, this may not be appropriate to guide empirical therapy because of variations in patient populations.

View Article and Find Full Text PDF

Objectives: The objective of this study was to describe the nosocomial spread of carbapenemase-producing enterobacteria and characterize a plasmid involved in KPC dissemination.

Methods: Two Klebsiella pneumoniae, one Escherichia coli and one Citrobacter freundii isolated from two patients were studied. Susceptibility profiles were obtained using Etest.

View Article and Find Full Text PDF

Background: Antimicrobial decision making in intensive care units (ICUs) is challenging. Unnecessary antimicrobials contribute to the development of resistant pathogens, Clostridium difficile infection and drug related adverse events. However, inadequate antimicrobial therapy is associated with mortality in critically ill patients.

View Article and Find Full Text PDF