More people now contract the drug-resistant “golden staph” superbug in the community, rather than hospitals

A study published in the Medical Journal of Australia this week looked at data from almost 40,000 people, and found that over 50% of people carrying antibiotic-resistant golden staph had not been admitted to hospital in the past year.

This means a change in focus for infection control and antibiotic stewardship strategies is needed, the authors say.

Methicillin-resistant Staphylococcus aureus (MRSA) is carried by between 0.7% and 2.2% of the Australian population, but was responsible for about 20% of S. aureus bacteraemia events in 2015, wrote the authors, led by Associate Professor John Ferguson, microbiologist and infectious diseases specialist at John Hunter Hospital in Newcastle.

The researchers used a case series of 39,231 patients who provided specimens during 2008–2014 from which S. aureus was isolated by the Hunter New England Local Health District public pathology provider.

The investigators analysed the data, intending to identify groups at risk of MRSA infection, patterns of antimicrobial resistance, and the proportion of patients with MRSA infections but no history of recent hospitalisation.

They found that 56.9% of patients from whom MRSA was isolated had not been admitted to a public hospital in the past year.

Patients with community-associated MRSA were more likely to be younger (less than 40 years old), Indigenous Australians, or residents of an aged care facility.

The proportion of MRSA isolates that included the dominant multi-resistant strain (“AUS-2/3-like”) decreased from 29.6% to 3.4% during the study period, as did the rates of hospital origin MRSA in two of the major hospitals in the region.

“Our findings reflect progress in reducing [hospital onset) MRSA (HO-MRSA) rates, with MRSA isolation rates declining in the two largest hospitals,” the authors write.

“Reduced HO-MRSA rates have been documented elsewhere in Australia and attributed, in part, to the national hand hygiene initiative.

“Our results suggest that, to reduce the prevalence of non-multi-resistant phenotypes, the focus of control measures should move from the health care setting to the community.

“To meet the challenges of community-acquired MRSA, expanding infection control and antimicrobial stewardship measures beyond the hospital system is needed.

“National surveillance of MRSA is increasingly urgent, enabling reliable data from both public and private pathology providers to be collected and targeted and generalised control strategies to be identified and evaluated.”

Dr Ferguson then told MJA InSight, in an exclusive podcast, that surveillance is the key priority.

“We need to know which sections of the community are more affected because they then become the focus of control efforts,” he said.

“The second thing is, in front of infection control, is probably antibiotic stewardship. Antibiotic use in the community is clearly fueling transmission and susceptibility, and really the same approach to stewardship [as in hospitals] has to happen, and [particularly] that stewardship [needs to happen] in aged care facilities more than anything.

“The third thing is infection control, and that can be focused on groups that are experiencing outbreaks, and those might be institutional outbreaks or outbreaks within the community. [We need to be] teaching basic hygiene, hand washing etc.”

Hospital-style infection control is “very tricky” to undertake in the community setting, but basic hygiene measures, as well as GP infection control measures, can help.