Publications by authors named "Jon Iredell"

Article Synopsis
  • 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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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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Purpose: Robust biomarkers that predict disease outcomes amongst COVID-19 patients are necessary for both patient triage and resource prioritisation. Numerous candidate biomarkers have been proposed for COVID-19. However, at present, there is no consensus on the best diagnostic approach to predict outcomes in infected patients.

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Article Synopsis
  • The study aimed to evaluate whether selective decontamination of the digestive tract (SDD) lowers in-hospital mortality in critically ill adults.
  • A total of 5,982 mechanically ventilated patients from 19 ICUs in Australia participated in a randomized trial contrasting SDD treatment with standard care over two alternating 12-month periods.
  • Results showed no significant difference in in-hospital mortality rates between the two groups, with 27% deaths in the SDD group versus 29% in the control, indicating that SDD may not have a substantial impact on mortality.
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Importance: Extended-spectrum β-lactamases mediate resistance to third-generation cephalosporins (eg, ceftriaxone) in Escherichia coli and Klebsiella pneumoniae. Significant infections caused by these strains are usually treated with carbapenems, potentially selecting for carbapenem resistance. Piperacillin-tazobactam may be an effective "carbapenem-sparing" option to treat extended-spectrum β-lactamase producers.

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Multidrug- and colistin-resistant Salmonella enterica serotype 4,[5],12:i:- sequence type 34 is present in Europe and Asia. Using genomic surveillance, we determined that this sequence type is also endemic to Australia. Our findings highlight the public health benefits of genome sequencing-guided surveillance for monitoring the spread of multidrug-resistant mobile genes and isolates.

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Objective: To elicit the views of well-informed community members on the acceptability of proposed policy interventions designed to improve community use of antibiotics in Australia.

Design: Two community juries held in 2016.

Setting And Participants: Western Sydney and Dubbo communities in NSW, Australia.

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Resistance of the Enterobacteriaceae to antibiotics, especially of the β lactam type, is increasingly dominated by the mobilization of continuously expressed single genes that encode efficient drug modifying enzymes. Strong and ubiquitous selection pressure has seemingly been accompanied by a shift from "natural" resistance, such as inducible chromosomal enzymes, membrane impermeability, and drug efflux, to the modern paradigm of mobile gene pools that largely determine the epidemiology of modern antibiotic resistance. In this way, antibiotic resistance is more available than ever before to organisms such as Escherichia coli and Klebsiella pneumoniae that are important causes of major sepsis.

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Background: Gram-negative bacteria such as Escherichia coli or Klebsiella spp. frequently cause bloodstream infections. There has been a worldwide increase in resistance in these species to antibiotics such as third generation cephalosporins, largely driven by the acquisition of extended-spectrum beta-lactamase or plasmid-mediated AmpC enzymes.

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An important role of the clinical microbiology laboratory is to provide rapid identification of bacteria causing bloodstream infection. Traditional identification requires the sub-culture of signaled blood culture broth with identification available only after colonies on solid agar have matured. MALDI-TOF MS is a reliable, rapid method for identification of the majority of clinically relevant bacteria when applied to colonies on solid media.

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The Gram-Negative 'Superbugs' Conference of the Australasian Society for Infectious Diseases, Gold Coast, Queensland, Australia, 2-3 August 2013 The Australian Society for Infectious Diseases hosted a national conference focused specifically on raising awareness of and contemplating solutions to the rise in antimicrobial resistance, especially in Gram-negative bacteria. Presentations were primarily informative, although some lively interactive sessions were held, particularly to debate contentious areas and to discuss options for policy makers and practitioners in infection control and antimicrobial stewardship. The conference brought together a diversity of backgrounds and interests, and was the first national meeting focused on this area.

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Motivation: Larger than gene structures (LGS) are DNA segments that include at least one gene and often other segments such as inverted repeats and gene promoters. Mobile genetic elements (MGE) such as integrons are LGS that play an important role in horizontal gene transfer, primarily in Gram-negative organisms. Known LGS have a profound effect on organism virulence, antibiotic resistance and other properties of the organism due to the number of genes involved.

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Background: Gene discovery algorithms typically examine sequence data for low level patterns. A novel method to computationally discover higher order DNA structures is presented, using a context sensitive grammar. The algorithm was applied to the discovery of gene cassettes associated with integrons.

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The epidemiology of emerging antibiotic resistance genes in Asia is inadequately defined and studies within the major pools of transmissible genes such as integron gene cassettes are important. One hundred and twenty-two non-repetitive Acinetobacter spp. isolates were obtained from inpatients of a major hospital in South China.

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Pseudomonas aeruginosa and Burkholderia cepacia are the major pathogens that colonize the airway surface and cause progressive respiratory failure and high mortality, especially in cystic fibrosis (CF) patients. Tobramycin is the treatment of choice, but persistent usage enables the infectious organisms to activate defence mechanisms, making eradication rarely successful. Combinations of antibiotic and nonantibiotic compounds have been tested in vitro against P.

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Twenty-two non-repetitive carbapenem-resistant Acinetobacter baumannii isolates were obtained from Intensive Care Unit patients. All of the isolates carried bla(OXA-23), bla(OXA-66), a novel cephalosporinase-encoding gene (bla(ADC-25)) and a class 1 integron with an aacC1-orfP-orfQ-aadA1a cassette array and had identical enterobacterial repetitive intergenic consensus (ERIC) profiles. ISAba1 was found upstream of bla(OXA-23), but was not associated with bla(OXA-66) or bla(ADC-25).

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The greatest impact of microbiology data on clinical care is in the critically ill. Unfortunately, this is also the area in which microbiology laboratories are most often non-contributive. Attempts to move to rapid, culture-independent diagnostics are driven by the need to expedite urgent results.

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In the last few years, phenotypically carbapenem resistant Acinetobacter strains have been identified throughout the world, including in many of the hospitals and intensive care units (ICUs) of Australia. Genotyping of Australian ICU outbreak-associated isolates by pulsed-field gel electrophoresis of whole genomic DNA indicated that different strains were cocirculating within one hospital. The carbapenem-resistant phenotype of these and other Australian isolates was found to be due to carbapenem-hydrolyzing activity associated with the presence of the blaOXA-23 gene.

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