Over a year ago, I wrote a few posts about changes to Clinical and Laboratory Standards Institute (CLSI) veterinary antimicrobial susceptibility testing guidelines. When a bacterium is grown in a lab and tested for susceptibility to different drugs, the lab looks to these CLSI guidelines to determine whether they should consider the bug susceptible
antibiotics
Antimicrobial Prophylaxis in Animals: A Primer
If I asked 100 random people on the street “should we be giving antibiotics to healthy animals?” I’m pretty sure most or all of them would say “no.“
That makes sense in a lot of ways. We should save antimicrobials to treat sick individuals (especially people), and we shouldn’t use antimicrobials in…
Infographic: Canine Acute Diarrhea Treatment
Back in March 2024, I wrote a post about a systematic review of the efficacy of antibiotics and probiotics and the associated treatment guidelines for acute diarrhea in dogs from the European Network for Optimization of Veterinary Antimicrobial Treatment (ENOVAT). Now, we have an ENOVAT/WSAVA infographic to put all that into a…
Global Impact of Antimicrobial Resistance (AMR) in Humans and Animals
Antimicrobial resistance (AMR) is a big problem with a crappy marketing plan. It’s been termed a “silent pandemic,” and it has huge health and financial impacts that are only going to get worse if we don’t act. Unfortunately, even though we’ve been battling this issue for decades, the average person doesn’t know about it, or…
Acute Diarrhea in Dogs: What’s the Evidence For Different Treatments?
Acute diarrhea is pretty common in dogs. It’s pretty common in people too, but our approach in dogs versus people is VERY different:
- Diarrheic dogs often get taken to a veterinarian ASAP.
- People with acute diarrhea rarely go to a physician.
Why is the approach so different?

It has nothing to do with severity of…
New WHO Medically Important Antimicrobial List
Hot off the press (at long last), here is the latest version of the World Health Organization’s Medically Important Antimicrobial List.
What is the WHO Medically Important Antimicrobial List?
It’s a document that categorizes all the classes of antimicrobials that are used in people and/or animals by how important they are to human medicine…
New CLSI Breakpoints For Veterinary Medicine: How to Interpret Results While Labs Are Updating Their Protocols, Part 3: Pseudomonas

In the first two parts of this series, I explained a lot of the changes that have been made to the CLSI veterinary antimicrobial susceptibility testing guidelines, specifically those related to staphylococci and Enterobacterales (which includes E. coli and friends). There’s less to say about Pseudomonas, but these changes will impact our…
New CLSI Breakpoints For Veterinary Medicine: How to Interpret Results While Labs Are Updating Their Protocols, Part 2: Staph, Enterobacterales and Fluoroquinolones in Dogs
The Clinical and Laboratory Standards Institute (CLSI) has updated their main veterinary testing standards document: VET01SEd7E Performance Standards for Antimicrobial Disk and Dilution Susceptibility Tests for Bacteria Isolated From Animals, 7th Edition. Check out earlier posts for an overview of the relevant changes, and more specifics about the standards for staphylococci and chloramphenicol…
New CLSI Breakpoints For Veterinary Medicine: How to Interpret Results While Labs Are Updating Their Protocols, Part 1: Staph and Chloramphenicol

Yesterday, I wrote a post about a new version of CLSI’s Performance Standards for Antimicrobial Disk and Dilution Susceptibility Tests for Bacteria Isolated From Animals. There are some major changes in this update, and I sympathize with the diagnostic labs that now have to update their testing and reporting. It won’t happen overnight, because…
Updated CLSI Veterinary Susceptibility Testing Guidance: What Veterinarians Need to Know (Spoiler… This One Has Lots of Relevant Changes!)
Diagnostic testing is a cornerstone of veterinary medicine that helps us optimize patient care, but there’s a lot of science behind it that people often forget. We collect a sample, send it off for testing and magically get the results, often without putting a lot of thought into what happens at the lab. Labs (should)…