Publications by authors named "Adam D Irwin"

Aim: COVID-19 has brought unprecedented challenges to the healthcare system. The rapid spread of the virus, laboratory burn-out, exhausted staff, diagnostic uncertainty and lack of guidelines cumulatively disrupted hospital antimicrobial stewardship (AMS) programs. This scoping review evaluated how the COVID-19 pandemic has impacted the implementation of AMS, particularly within the context of clinical audits.

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  • Rising rates of antimicrobial resistance (AMR) were noted in Staphylococcus aureus and Enterococcus spp. in Australia, with a significant number of blood stream infections (BSIs) occurring in children.
  • The Australian Group on Antimicrobial Resistance (AGAR) analyzed 2,091 S. aureus and 534 enterococcal BSIs over nine years, revealing key trends in community vs. hospital onset infections and varying resistance levels.
  • A shift in resistance profiles was observed, especially in Enterococcus faecium, prompting the need for detailed and age-stratified reporting of AMR data.
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Background: Gram-negative bloodstream infections are associated with significant morbidity and mortality in children. Increasing antimicrobial resistance (AMR) is reported globally, yet efforts to track pediatric AMR at a national level over time are lacking.

Methods: The Australian Group on Antimicrobial Resistance (AGAR) surveillance program captures clinical and microbiological data of isolates detected in blood cultures across Australia.

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Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. Time to receive effective therapy is a primary determinant of mortality in patients with sepsis. Blood culture is the reference standard for the microbiological diagnosis of bloodstream infections, despite its low sensitivity and prolonged time to receive a pathogen detection.

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  • Enterobacterales bloodstream infections (E-BSI) pose a significant health threat to children in Queensland, Australia, with a notable rise in infection rates observed from 2000 to 2019.
  • A total of 1980 E-BSI cases were recorded, leading to an increase in the standardized incidence rate from 7.3 to 12.9 cases per 100,000 child years, with E. coli and Salmonella sp. being the most common pathogens.
  • The study highlights the growing antimicrobial resistance, particularly in E. coli, and emphasizes the need for including children in clinical trials for more effective treatment options.
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  • The study highlights the emergence of the M1UK variant of Streptococcus pyogenes as a significant global health threat, differing from the original M1global genotype by 27 SNPs and showing increased virulence through speA superantigen expression.
  • Researchers developed a rapid allele-specific real-time PCR assay to detect M1UK strains and used whole-genome sequencing on 51 clinical isolates to assess the distribution of various emm (sub)types, finding M1UK dominant among the invasive and non-invasive strains.
  • The findings confirm the ongoing presence of M1UK strains in Queensland, Australia, and suggest that the assay can be effectively used for enhanced surveillance of this particular pathogen.
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From 1 January 2020 to 31 December 2021, thirty-eight institutions across Australia submitted data to the Australian Group on Antimicrobial Resistance (AGAR) from patients aged < 18 years (AGAR-Kids). Over the two years, 1,679 isolates were reported from 1,611 patients. This AGAR-Kids report aims to describe the population of children and adolescents with bacteraemia reported to AGAR and the proportion of resistant isolates.

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  • A 3-year study in five Australian children's hospitals found that Gram-negative bloodstream infections (GNBSIs) significantly affect children under 5, often occurring in those with existing health issues and central venous catheters.
  • Out of 931 infection episodes involving 818 children, community onset was common, and 71% of cases involved antibiotic-resistant pathogens, particularly from the Enterobacterales family.
  • The study highlighted a 3% in-hospital mortality rate, with infections involving third-generation cephalosporin resistant Enterobacterales linked to higher mortality rates, suggesting a need for improved prevention and treatment strategies.
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  • * A study of 58 NMEC isolates revealed significant genetic diversity, with key prevalent sequence types identified, but no single virulence gene profile was universally found across all samples.
  • * Patients experiencing recurring infections despite antibiotic treatment showed severe gut dysbiosis, suggesting that the NMEC strain may persist in gut flora, leading to potential reinfection.
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Purpose: Early recognition and effective treatment of sepsis improves outcomes in critically ill patients. However, antibiotic exposures are frequently suboptimal in the intensive care unit (ICU) setting. We describe the feasibility of the Bayesian dosing software Individually Designed Optimum Dosing Strategies (ID-ODS™), to reduce time to effective antibiotic exposure in children and adults with sepsis in ICU.

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Bacteria adapt to selective pressure in their immediate environment in multiple ways. One mechanism involves the acquisition of independent mutations that disable or modify a key pathway, providing a signature of adaptation via convergent evolution. Extra-intestinal pathogenic Escherichia coli (ExPEC) belonging to sequence type 95 (ST95) represent a global clone frequently associated with severe human infections including acute pyelonephritis, sepsis, and neonatal meningitis.

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We aimed to evaluate the performance of Oxford Nanopore Technologies (ONT) sequencing from positive blood culture (BC) broths for bacterial identification and antimicrobial susceptibility prediction. Patients with suspected sepsis in four intensive care units were prospectively enrolled. Human-depleted DNA was extracted from positive BC broths and sequenced using ONT (MinION).

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Background: Cytomegalovirus (CMV) is a viral infection which establishes lifelong latency, often reactivating and causing disease in immunosuppressed individuals, including haematopoietic stem cell transplant (HSCT) recipients. Treatment can be problematic due to antiviral resistance which substantially increases the risk of patient mortality. Diagnostic testing capabilities for CMV antiviral resistance in Australia and elsewhere have traditionally relied on gene-specific Sanger sequencing approaches, however, are now being superseded by next generation sequencing protocols.

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Cytomegalovirus (CMV) is a ubiquitous virus which causes a mild illness in healthy individuals. In immunocompromised individuals, such as children receiving haematopoietic stem cell transplantation, CMV can reactivate, causing serious disease and increasing the risk of death. CMV can be effectively treated with antiviral drugs, but antiviral resistance is an increasingly common complication.

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Background: Due to their prevalence worldwide, the β-lactamases CTX-M and plasmid-mediated CMY-2 are important antimicrobial resistance enzymes in a clinical setting. While culture- and PCR-based detection methods exist for these targets, they are time consuming and require specialist equipment and trained personnel to carry out.

Methods: In this study, three rapid diagnostic single-plex and a prototype triplex assay were developed, using recombinase polymerase amplification with lateral flow detection (RPA-LF), and tested for their sensitivity and specificity using two isolate DNA panels ( = 90 and  = 120 isolates).

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  • A new variant of Streptococcus pyogenes serotype M1 has been identified in the UK, linked to increases in scarlet fever cases and invasive infections due to its enhanced SpeA superantigen expression.
  • This M1 variant can be distinguished from its predecessor by specific genetic mutations but the reason for the increased SpeA expression remains unclear.
  • Researchers found that a single genetic change in the ssrA gene leads to higher SpeA expression in the M1 lineage in Australia, signaling a need for better global monitoring of such variants.
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  • The study analyzed Moraxella species bloodstream infections (BSIs) in Queensland, Australia, over a 19-year period, highlighting their rarity and low overall incidence.
  • Among the 375 BSIs documented, M. catarrhalis was the most common isolate, with infants showing the highest incidence rates, while males and those with comorbidities were at greater risk overall.
  • The 30-day case-fatality rate was low at 4%, but significantly higher in adults compared to children, indicating a need for further understanding of risk factors associated with these infections.
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Objectives: To develop instrument-free point-of-care methods using recombinase polymerase amplification (RPA) technology coupled with a simple lateral flow detection system to detect Neisseria gonorrhoeae and susceptibility to ciprofloxacin.

Methods: For identification of gonococcal infection, an RPA-based method was developed targeting the gonococcal porA pseudogene (NG-porA-RPA). For ciprofloxacin susceptibility, predictive WT sequences at codons 91 and 95 of the gonococcal gyrA DNase gene were targeted.

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Background: Neonatal sepsis is a significant global health issue associated with marked regional disparities in mortality. Antimicrobial resistance (AMR) is a growing concern in Gram-negative organisms, which increasingly predominate in neonatal sepsis, and existing WHO empirical antibiotic recommendations may no longer be appropriate. Previous systematic reviews have been limited to specific low- and middle-income countries.

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Background: Sepsis contributes significantly to morbidity and mortality globally. In Australia, 20,000 develop sepsis every year, resulting in 5,000 deaths, and more than AUD$846 million in expenditure. Prompt, appropriate antibiotic therapy is effective in improving outcomes in sepsis.

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Background: Oxford Nanopore Technology (ONT) long-read sequencing has become a popular platform for microbial researchers due to the accessibility and affordability of its devices. However, easy and automated construction of high-quality bacterial genomes using nanopore reads remains challenging. Here we aimed to create a reproducible end-to-end bacterial genome assembly pipeline using ONT in combination with Illumina sequencing.

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Carbapenemase-producing organisms (CPOs) pose a serious clinical threat and rapid detection tools are essential to aid in patient management. We developed rapid and simple molecular tests to detect bla and bla carbapenemase genes using recombinase polymerase amplification (RPA) combined with a lateral flow detection. The tests could provide results in approximately 15 min when using DNA extracts, with limits of detection of 9.

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This study aimed to suggest an initial pediatric vancomycin dose regimen through population pharmacokinetic-pharmacodynamic modeling. A population pharmacokinetic approach was used to analyze vancomycin concentration-time data from a large pediatric cohort. Pharmacokinetic target attainment for patients with bloodstream isolates was compared with clinical outcome using logistic regression and classification and regression trees.

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