Indian scientists isolate Candida auris in the environment
A team of Indian scientists yesterday reported the detection of Candida auris isolates from two sampling sites on islands in the Indian Ocean—the first time the multidrug-resistant yeast has been isolated in a natural environment. The discovery was reported in mBio.
Since it was first identified in a Japanese patient in 2009, C auris has spread to hospitals around the world, and has been declared an urgent health threat by the US Centers for Disease Control and Prevention. Because the yeast is capable of growing at higher temperatures and can tolerate hypersaline environments more than other Candida species, scientists in recent years have hypothesized that it may have existed in wetlands before becoming a clinically relevant pathogen, and that its emergence could be linked to global warming's effects on wetlands.
To further explore this hypothesis, scientists from the University of Delhi collected 48 samples of sediment and seawater from coastal wetlands, sandy beaches, tidal marshes, and mangrove swamps around the Andaman Islands in the Bay of Bengal. The climate of these islands is tropical, with hot and humid conditions.
The team isolated C auris from samples at two sites, with two isolates found in a salt marsh wetland and 22 on a sandy beach. Antifungal susceptibility testing showed that one of the salt marsh isolates and all 22 from the beach—which was high in human activity—were multidrug resistant. Whole-genome sequencing revealed that the isolates were genetically distinct from C auris isolates from Indian hospitals but broadly related to clade 1, which includes isolates from South Asia.
"The isolation of C. auris from this natural environment is noteworthy considering that until now this yeast has not been identified outside hospital environmental settings," the authors wrote.
They add that the significance of the discovery, its connection to human infections, and whether the pathogen exists in other ecological niches, need to be further explored.
Mar 16 mBio study
VA study links contact precautions with reduced MRSA transmission
Department of Veterans Affairs (VA) hospitals that conducted contact precautions for patients with methicillin-resistant Staphylococcus aureus (MRSA) had a nearly 50% reduction in MRSA transmission, researchers reported this week in JAMA Network Open.
In the study, researchers from the VA Salt Lake City Health Care System and the University of Utah School of Medicine applied mathematical models to data from patients admitted to VA acute care hospitals from January 2008 through December 2017 to determine whether contact precautions for MRSA carriers had any impact on patient-to-patient transmission. Contact precautions, which involve the use of gloves and gowns by healthcare staff when interacting with MRSA carriers and their environment, are one element of the MRSA Prevention Initiative introduced by the VA in 2007, but their effectiveness has been questioned. Other elements include surveillance and hand hygiene.
The cohort included 108 hospitals with more than 2 million unique patients, and over the study's duration, they had more than 5.6 million admissions and 8.4 million MRSA surveillance tests (9.3% positive). Among all admissions, 14.1% required contact precautions during their stay based on a positive MRSA test result. Pooled estimates found associations between contact precautions and transmission to be stable from 2008 through 2017, with estimated transmission reductions ranging from 43% (95% credible interval [CrI], 38% to 48%) to 51% (95% CrI, 46% to 55%). Over the entire 10-year study period, contact precautions reduced transmission by 47% (95% CrI, 45% to 49%).
Larger hospitals and those with higher admission screening compliance saw additional reductions in transmission associated with contact precautions compared with smaller hospitals with lower screening compliance. VA hospitals in the southern states saw less transmission reduction linked to contact precautions compared with facilities in other regions.
The study authors say the results provide an explanation for the decline in MRSA acquisition rates in VA hospitals since the MRSA Prevention Initiative began.
Mar 15 JAMA Netw Open study