Blog | Monday, May 6, 2019

SENTRY at 20: So many bugs!


The SENTRY Antimicrobial Surveillance Program was begun at the University of Iowa in 1997, moving a few years later to JMI Laboratories (also in Iowa!). Since inception, it's been an industry-funded platform that performs central laboratory testing of clinical isolates of bacteria and fungi from centers around the world. The isolate submission process has been consistent over time, involving submission of organisms from consecutive episodes of infection at specified body sites (more information here and in the many publications that have come from SENTRY).

So SENTRY has been operating for >20 years, and there are hundreds of thousands of isolates characterized. The major trends are reported in an OFID supplement and in recent publications in JAC and AAC. The supplement articles and the AAC report on trends in 20 years of bloodstream infection (BSI) isolates are open access—take a look if interested!

I'll focus briefly just on the AAC report (which I first-authored, so that's shameless self-promotion right there)—two major points, each of which confirms on a large scale what regional surveillance programs have reported:
S. aureus and E. coli dominate the BSI landscape—together account for >40% of all episodes reported to SENTRY. Continued focus on prevention, detection and treatment of these two bad actors is critical, and IMO should include vaccine approaches, despite the disappointments to date.
• There's an interesting divergence in proportion of BSI caused by important resistance phenotypes among Gram-positives (MRSA, VRE, DRE, etc.) versus Gram-negatives (ESBL, CRE) over the second decade of surveillance (2005-2016). The Gram-positive resistance phenotypes are stable-to-declining, whereas Gram-negative phenotypes steadily increase (as proportion of BSI episodes) over the entire surveillance period.

The decline in MRSA as a proportion of all SA BSI is particularly striking, occurring as it does at the same time worldwide (and at all body sites, both healthcare- and community-onset, as more detail in the OFID report of all SENTRY S. aureus confirms). As Eli and I discussed in this JAMA editorial almost 10 years ago (Still behind a paywall after 10 years? What gives?), this is not easily explained by hospital-based infection control interventions. The waxing and waning of epidemic clones of MRSA is more likely to be informative. There is so much we still don't understand about an organism (S. aureus) that lives in relative harmony with 20-30% of the human population when it isn't causing horrendous, difficult-to-treat infections.

Finally, the scope and number of isolates collected by SENTRY and similar programs represent an underutilized public health resource. Regulatory requirements for drug development and approval mandate surveillance for AMR. Better partnerships between public health authorities and the industry sponsors of such surveillance programs could enhance surveillance and response, particularly in the genomic era when ready access to large isolate collections can be so powerful. Some of this is already happening, but more could be done.

Daniel J. Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. This post originally appeared at the blog Controversies in Hospital Infection Prevention.