Australian Staphylococcus aureus Sepsis Outcome Programme annual report, 2013.

From 1 January to 31 December 2013, around Australia 26 institutions around Australia participated in the Australian Staphylococcal Sepsis Outcome Programme (ASSOP). The aim of ASSOP 2013 was to determine the proportion of Staphylococcus aureus bacteraemia (SAB) isolates in Australia that are antimicrobial resistant, (with particular emphasis on susceptibility to methicillin) and to characterise the molecular epidemiology of the isolates. Overall 19.1% of the 2,010 SAB episodes were methicillin resistant, which is significantly higher than that reported in most European countries. Although the SAB 30-day all cause mortality appears to be decreasing in Australia, methicillin-resistant SAB associated mortality remains high (20.1%) and was significantly higher than methicillin-sensitive SAB associated mortality (13%) (P< 0.0001). With the exception of the ß-lactams and erythromycin, antimicrobial resistance in methicillin sensitive S. aureus remains rare. However, in addition to the ß-lactams, approximately 50% of methicillin-resistant S. aureus (MRSA) were resistant to erythromycin and ciprofloxacin and approximately 20% were resistant to co-trimoxazole, tetracycline and gentamicin. Linezolid, daptomycin and teicoplanin resistance was detected in a small number of S. aureus isolates. Resistance to vancomycin was not detected. Resistance was largely attributable to 2 healthcare associated MRSA clones; ST22-IV [2B] (EMRSA-15) and ST239-III [3A] (Aus-2/3 EMRSA). ST22-IV [2B] (EMRSA-15) has now become the predominant healthcare associated clone in Australia. Approximately 60% of methicillin-resistant SAB were due to community associated clones. Although polyclonal, almost 50% of community associated clones were characterised as ST93-IV [2B] (Queensland CA-MRSA) and ST1-IV [2B] (WA1). CA-MRSA, in particular the ST45-V [5C2&5] (WA84) clone, has acquired multiple antimicrobial resistance determinants including ciprofloxacin, erythromycin, clindamycin, gentamicin and tetracycline. As CA-MRSA is well established in the Australian community, it is important antimicrobial resistance patterns in community and healthcare associated SAB is monitored as this information will guide therapeutic practices in treating S. aureus sepsis.

Australian Enterococcal Sepsis Outcome Programme annual report, 2013.

From 1 January to 31 December 2013, 26 institutions around Australia participated in the Australian Enterococcal Sepsis Outcome Programme (AESOP). The aim of AESOP 2013 was to determine the proportion of enterococcal bacteraemia isolates in Australia that are antimicrobial resistant, and to characterise the molecular epidemiology of the Enterococcus faecium isolates. Of the 826 unique episodes of bacteraemia investigated, 94.6% were caused by either E. faecalis (56.1%) or E. faecium (38.5%). Ampicillin resistance was not detected in E. faecalis but was detected in over 90% of E. faecium. Vancomycin non-susceptibility was reported in 0.2% and 40.9% of E. faecalis and E. faecium respectively and was predominately due to the acquisition of the vanB operon. Overall, 41.6% of E. faecium harboured vanA or vanB genes. The percentage of E. faecium bacteraemia isolates resistant to vancomycin in Australia is significantly higher than that seen in most European countries. E. faecium isolates consisted of 81 pulsed-field gel electrophoresis pulsotypes of which 72.3% were classified into 14 major pulsotypes containing five or more isolates. Multilocus sequence typing grouped the 14 major pulsotypes into clonal cluster 17, a major hospital-adapted polyclonal E. faecium cluster. Of the 2 predominant sequence types, ST203 (80 isolates) was identified across Australia and ST555 (40 isolates) was isolated primarily in the western and central regions (Northern Territory, South Australia and Western Australia) respectively. In conclusion, the AESOP 2013 has shown enterococcal bacteraemias in Australia are frequently caused by polyclonal ampicillin-resistant high-level gentamicin resistant vanB E. faecium, which have limited treatment options.

Enterobacteriaceae Sepsis Outcome Programme annual report, 2013.

The Australian Group on Antimicrobial Resistance performs regular period-prevalence studies to monitor changes in antimicrobial resistance in selected enteric Gram-negative pathogens. The 2013 survey focussed for the first time on blood stream infections. Four thousand nine hundred and fifty-eight Enterobacteriaceae species were tested using commercial automated methods (Vitek® 2, BioMérieux; Phoenix™, BD). The results were analysed using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (January 2014). Of the key resistances, non-susceptibility to the third-generation cephalosporin, ceftriaxone, was found in 7.5%/7.5% (CLSI/EUCAST criteria respectively) of Escherichia coli; 6.3%/6.3% of Klebsiella pneumoniae, and 7.4%/7.4% of K. oxytoca. Non-susceptibility rates to ciprofloxacin were 10.3%/11.3% for E. coli, 4.6%/7.5% for K. pneumoniae, 0.6%/0.6% for K. oxytoca, and 3.6%/6.1% in Enterobacter cloacae. Resistance rates to piperacillin-tazobactam were 3.1%/6.2%, 4.2%/7.0%, 11.9% /12.6%, and 17.3% /22.2% for the same 4 species respectively. Fourteen isolates were shown to harbour a carbapenemase gene, 9 blaIMP, 3 blaKPC, and 2 blaNDM.