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Introduction
Current institution
Publications
Publications (45)
Effective implementation of antibiotic stewardship, especially in critical care, is limited by a lack of direct comparative investigations on how different antibiotics impact the microbiota and antibiotic resistance rates. We investigated the impact of two commonly used antibiotics, third-generation cephalosporins (3GC) and piperacillin/tazobactam...
Antimicrobial susceptibility testing with the BD Phoenix system on bacterial cell pellets generated from blood culture broths using the Bruker MALDI Sepsityper kit was evaluated. Seventy-six Gram negative isolates, including 12 with defined multi-resistant phenotypes, had antibiotic susceptibility testing (AST) performed by Phoenix on the cell pell...
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 identif...
We aimed to streamline the diagnosis of gastrointestinal disease by producing multiplexed real time polymerase chain reaction (PCR) panels employing universal sample processing for DNA and RNA containing pathogens.A total of 487 stored, previously characterised stool samples comprising bacterial, viral, protozoan and Clostridium difficile positive...
Background
Management of prelabour rupture of membranes at term (37 weeks gestation or later) (TPROM) remains complicated in the absence of a rapid assay for group B streptococcus (GBS) colonisation. AimsTo evaluate the accuracy and clinical utility of a commercial PCR assay, compared with culture, for detection of GBS colonisation in pregnant wome...
Based on the relationship between Clostridium difficile surface layer protein A (slpA) sequence types (STs) and PCR-ribotypes (RTs), a multiplex polymerase chain reaction (mPCR) assay was developed to rapidly confirm C. difficile toxigenicity and, simultaneously, to identify any of five slpA STs, gr, hr, fr, gc8 and 078, that usually correspond wit...
The application of matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) mass spectrometry (MS) directly to blood culture broth has potential to identify bloodstream infection earlier and facilitate timely management. We prospectively tested a novel, rapid, and inexpensive in-house spin-lysis protocol with formic acid extraction an...
Early appropriate antibiotic treatment reduces mortality in severe sepsis, but current methods to identify antibiotic resistance still generally rely on bacterial culture. Modern diagnostics promise rapid gene detection, but the apparent diversity of relevant resistance genes in Enterobacteriaceae is a problem. Local surveys and analysis of publicl...
Blood pressure (BP) cuffs are potential vectors for transmission of multi-resistant organisms (MROs). The present study aims to determine MRO colonisation rates in BP cuffs from areas of high patient flow as an assessment of the quality of disinfection and infection control practices.
BP cuffs in the ED, high dependency unit (HDU) and operating the...
The early initiation of targeted antibiotic therapy in patients with bacteraemia and septic shock impacts favourably on outcomes. Rapid methods are therefore increasingly employed for bacterial identification directly from positive blood culture bottles, but with variable success. We evaluated the performance of the Gram positive-12 multiplex tande...
Among the agents of community-acquired septic shock in countries such as Australia and the US, the major risk of antibiotic failure not easily identified by a simple gene target resides with the Enterobacteriaceae, particularly Escherichia coli and Klebsiella pneumoniae.
Streptococcus pneumoniae and Staphylococcus aureus are easily managed with a s...
The prevalence of hospital and community-acquired Clostridium difficile infection (CDI) has recently increased, particularly in the Northern Hemisphere, with spread of the hypervirulent 027/NAP/BI strain; so far, this strain is uncommon in Australia.…
Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) is a novel method for the direct identification of bacteria from blood culture broths. We evaluate for the first time, the performance of the MALDI Sepsityper™ Kit and MS for the identification of bacteria compared to standard phenotypic methods using the ma...
We describe the success of adjunctive bacteriophage therapy for refractory Pseudomonas aeruginosa urinary tract infection in the context of bilateral ureteric stents and bladder ulceration, after repeated failure of antibiotics alone. No bacteriophage-resistant bacteria arose, and the kinetics of bacteriophage and bacteria in urine suggest self-sus...
A novel gene cassette, aacA43, was identified in the aadB-aacA43-oxa10-smr2 cassette array in a class 1 integron. Like related aminoglycoside-(6′)-acetyltransferases, AacA43 confers clinically relevant
resistance to kanamycin, tobramycin, and some less-used aminoglycosides but not to gentamicin. Although transferable on an
IncL/M plasmid, aacA43 wa...
To evaluate the effect of defined mutations in the major OmpK35 and OmpK36 porins in Klebsiella pneumoniae on the activity of two common plasmid-mediated AmpC enzymes.
Naturally occurring conjugative plasmids containing bla(DHA-1) and bla(CMY-2) were obtained from K. pneumoniae isolates in western Sydney. These were moved into K. pneumoniae ATCC138...
Identification and susceptibility testing of presumed Staphylococci in blood cultures requires >24 hours by routine phenotypic methods. ...
blaCTX-M genes, particularly blaCTX-M-15, are the dominant extended-spectrum β-lactamase (ESBL) genes among clinical isolates of Escherichia coli and Klebsiella pneumoniae in Sydney, Australia, where we also found one example of blaCTX-M-62, encoding a novel enzyme conferring ceftazidime resistance. ESBL genes were present in diverse community isol...
Diagnostic algorithms in commonly used automated bacterial identification systems fail to reliably identify a metallo-β-lactamase
in the Enterobacteriaceae. Misidentification as an extended-spectrum β-lactamase may result in inappropriate dismissal of drugs such as aztreonam in
favor of carbapenems, which may in turn select for a highly carabapenem...
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 strai...
The notification of "Gram-positive cocci, possibly staphylococcus" in a blood culture drawn from a seriously ill patient is responsible for a large amount of vancomycin prescribing in institutions where methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of bacteraemia. A duplex real-time TaqMan polymerase chain reaction target...
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. This is difficult in Gram-negative infection becaus...
Bacterial integrons are a useful PCR amplification target in epidemiological surveys of bacterial antibiotic resistance, and a variety of primers have been published. We describe multiplex PCR methodology to test for classes 1, 2 and 3 integron-associated integrases in boiled lysates of Gram-negative bacteria. We report on performance in Acinetobac...
