THE incidence of community-associated Staphylococcus aureus bloodstream infections (CA-SABs) is on the rise in Victoria and Western Australia, according to authors of a research letter published online by the Medical Journal of Australia.
Despite a decline in S. aureus infections acquired in health-care settings (HA-SABs), during 2016 and 2017 an increase in the number of CA-SABs was reported from affiliated hospitals to the Victorian Healthcare Associated Infection Surveillance System (VICNISS) and Healthcare Infection Surveillance Western Australia, prompting the latest research.
Led by Peter Doherty Institute for Infection and Immunity infectious diseases specialists Associate Professor Leon Worth from VICNISS and Professor Michael Richards from Royal Melbourne Hospital, the researchers analysed quarterly data for the period 1 January 2011 to 31 December 2016 from 93 Victorian public hospitals and 58 Western Australian public hospitals.
“A total of 10 320 SAB events were reported (7262 in Victoria, 3058 in WA); 6800 infections (65.9%) were community-associated, corresponding to an aggregate crude rate of 13.3 CA-SABs per 100 000 person-years,” the researchers found. “The incidence in each state increased significantly during the study period: 8% per year in Victoria and 6% per year in WA.
“The incidence of CA-SABs was higher among older patients and in men, and was particularly high for men over 60: the standardised incidence in this group was 50.9 cases in Victoria and 56.7 cases per 100 000 person-years in WA, twice the incidence among women of the same age (Victoria, 24.7; WA, 24.9 cases per 100 000 person-years).”
The researchers pointed out that some infected persons would have been managed entirely in private health care, meaning that “we will have underestimated the incidence of CA-SAB”.
The next step, the researchers wrote, is to characterise the isolates responsible for infection. This would “assist in identifying virulence factors and the relatedness of isolates”.
“Further evaluation of infection risks in people over 60 years of age is also needed for developing targeted prevention strategies,” they concluded.
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