New Study Reveals Shifting Trends in Antibiotic-Resistance for S aureus Infections

A new study released in JAMA Network Open has shed light on shifting trends in antibiotic-resistance trends, suggesting that outpatient clinicians “may need to tailor antibiotic prescribing for S aureus infections.” CIDRAP has the news.

The study, which looked at S aureus isolates from over 268,000 U.S. Veterans Health Administration (VHA) patients, found declines in the proportion of methicillin-resistant S aureus (MRSA) from 2010 through 2019, but increases in resistance to non-beta-lactam antibiotics like tetracyclines and trimethoprim-sulfamethoxazole (TMP-SMX).

MRSA isolates declined from 53.6% in 2010 to 38.8% in 2019, “with the decline observed across all US regions, though MRSA rates remained consistently higher in the South.” Among those isolates, tetracycline resistance rose from 3.6% to 12.8% in that time, and TMP-SMX resistance rose from 2.6% to 9.2%.

The authors of the study suggest that the higher rates of resistance in patients in the South could be done to such factors as sociodemographic factors like crowding and poverty, climate factors, and antibiotic prescribing patterns. They also suggest that “geographically specific antibiograms, particularly for outpatient facilities that serve a large patient catchment area, could better inform empirical therapy decisions, although evidence suggests that such antibiograms need to incorporate seasonality and patient-level information.”