The Clinical Burden of Community-Acquired Methicillin-Resistant Staphylococcus aureus in Far North Queensland

This study will look at the clinical burden of community-acquired methicillin-resistant staphylococcus aureus in Far North Queensland

The predominant focus of this project is on antimicrobial resistance. It is our goal to provide locally relevant prevalence data on CA-MRSA in Far North Queensland and thus ensure appropriate empirical therapy. This is particularly important in remote settings where laboratory data is often delayed or unavailable.

Project aims and hypotheses:

1. To examine the changing frequency of CA-MRSA as a proportion of all community acquired S.aureus infections across the Cairns and Cape York region over the past 20 years, from 1997-
   2016. This will be done with goal of providing definitive local epidemiological evidence on CAMRSA prevalence, and thus allowing for regional tailoring of empirical antibiotic therapy.
2. To examine the changing frequency of mupirocin resistance amongst S.aureus infections across the Cairns and Cape York region over the past 20 years, from 1997-2016.
3. To establish the difference in duration of hospital stay, adverse events, rates of ICU admission, and mortality in CA-MRSA bacteremia in patients treated with clindamycin vs. vancomycin in the Cairns and Cape York Region.

Given the combination of local anecdotal evidence, and studies from the Northern Territory, the investigating team is expecting to find a current prevalence of CA-MRSA of > 25%. This rate is also expected to have risen across the 20 year period, and to be higher in remote areas. We are also expecting a high level of mupirocin resistance.

In part 3 of our study we are expecting to find that treatment of CA-MRSA bacteraemia with clindamycin is non-inferior to vancomycin in terms of its impact on duration of hospital admission, rate of ICU admission and mortality.

The impetus to conduct this study has come from the anecdotal evidence provided by healthcare workers across the Cairns, Cape York and Torres region. They have begun to report on the noticeable inefficacy of beta-lactam antibiotics for traditionally sensitive community acquired S.aureus isolations. Studies from across Australia and the globe concur. 2-5 CA-MRSA is thought to be the cause of at least 15% of community acquired S.aureus infections, with an even greater prevalence in remote areas and Aboriginal and Torres Strait Islander populations. 5,6 However, local prevalence data does not yet exist, and it is this data that is crucial for the development of regionally-specific empirical antibiotic guidelines. Furthermore, we would like to establish whether mupirocin remains a suitable treatment for the eradication of S.aureus in those with persistent infections; an important issue in Far North Queensland. Lastly, we would like to establish whether clindamycin is non-inferior to vancomycin in the treatment of CA-MRSA bacteraemia.