As we continue with World Antibiotic Awareness Week, here are some more tidbits from the 2017 CARSS report.
- Hospital-associated C diff rates continue to decrease, with a fairly remarkable drop from 6.64/10000 patient days in 2011 to 4.04 in 2016.
- Community-associated C. difficile infection is still a big unknown. In 2015, 37% of C. difficile infection patients admitted to sentinel hospitals were thought to have infections that originated in the community. That’s not surprising given what we’ve been learning over the past 10 years, and the epidemiology of C diff is much more complex than previously assumed.
- There was a bit of an increase in MRSA rates in sentinel hospitals, from 2.84-3.13/10,000 patient dates between 2011 and 2016.
- Similar to C diff, community-associated MRSA has become an increasingly recognized problem. When origin is considered, hospital-associated MRSA actually decreased from 1.93-1.69/10,000.
- Pediatric hospital community-associated MRSA rates were higher than those in adult hospitals (1.56 vs 1.02). There was a big increase in pediatric MRSA bloodstream infection rates, something that’s obviously a concern given the potential severity of disease.
- In terms of strains, CMRSA10 (also known as USA100) continued its rise, while the old leader CMRSA2 continued to decline. Part of this is the result of more community MRSA cases (where CMRSA10 is predominant) and fewer hospital cases (when CMRSA2 has been the main strain).
- Along with the increase in numbers of cases of gonorrhea, resistance has also continued to increase. Azithromycin-resistance increased fro 1.3-47% from 2010-2015. Decreased susceptibility to cefixime and ceftriaxone increased from 1.1 and 1.9 to 2.9 and 3.5%, respectively, between 2014-2015.
Continuing our World Antibiotic Awareness Week blitz, let’s head back to the 2017 Canadian Antimicrobial Resistance Surveillance System report
Carbapenase-producing Enterobacteriaceae (CPE) are Gram negative bacteria (e..g E. coli, Klebsiella, Enterobacter) that are resistant to carbapenems, an important class of antibiotics. They’re a big concern because carbapenems are used for people with serious infections, and treatment options may be limited (since these strains are often resistant to many other drug classes too). Carbapenems aren’t used in food animals and are rarely used in companion animals, but resistance can be found in bacteria from animals. It’s probably driven by use of other antibiotic classes that are used in food animals that CPE are also resistant to. A big issue is that these bacteria are common inhabitants of the gut. Therefore, resistant strains can live happily in the intestinal tract for potentially long period of time, being passed in feces. (I probably don’t need to point out that cows poop a lot).
In Canada, screening of farm, slaughterhouse and retail samples was started in 2013, with a new technique added in 2016 to provide more sensitive detection.
- The good news….no CPE were identified amongst over 13,000 screened surveillance isolates.
- The somewhat concerning news….9/3,000 farm/retail/slaughterhouse samples were positive. That’s obviously a low rate but it’s not zero. All were seafood products. Three are stated as being imported, while my assumption is the other 6 were too (although I could be wrong…it’s not clear in the report). This highlights the fact that we don’t live in a bubble and bacteria could case less about immigration rules.
The fact that no CPE were identified in livestock or their associated products was great.
For now, at least.
It will probably happen but continued surveillance to identify and hopefully mitigate risks like this is important. We’re also continuing to look for CPE in companion animals. I’ve dealt with a few cases, but all were from the US. CPE in pets may end up similar to the situation with MRSA, whereby infections in pets are most often associated with transmission from infected owners, but food animals, food and the environment all remain potential ways that CPE could be spread from livestock.
At this point, CPE is rare in people in the community, but if it successfully spills out into the community from hospitals, we’ll likely see further spillover into domestic animals. Yet another reason why a multisector approach to antimicrobial stewardship is needed (yes, that’s a plug for CANresist, but it’s true).
The last post was about animals so let’s get to some human data from the 2017 Canadian Antimicrobial Resistance Surveillance System report.
In 2016, 247,014 kg of antibiotics were dispensed, most (>200K kg) through pharmacies, with ~40K kg through hospitals. Overall, ~92% of defined daily doses of antibiotics were dispensed through pharmacies.
- This is another example why there needs to be more work on community-level antimicrobial stewardship programs. Hospitals are an important place to address antimicrobial use, but the community can’t be ignored.
A couple hundred thousand kgs of antibiotics isn’t cheap. The total cost in 2016 was ~$766 million.
- How much of that was unnecessary isn’t known. However, even if we just think about antibiotic cost savings (ignoring resistance, complications and various other potential problems), reducing antibiotic use can have a big financial impact.
625 prescriptions were dispensed in the community for every 1000 people.
- This number has been pretty stable over the past few years, but varies across the country.
When provinces and territories are compared, Newfoundland is gets the dubious distinction of leading the way in prescription rates per 1000 people, at 954. The Territories (a combination of the Northwest Territories, Yukon and Nunavut) had the lowest rate, at 280/1000.
The most common drugs have remained pretty stable. Amoxicillin was the most common drug, followed by azithromycin and cephalexin.
Prescription rates for kids < 14 yrs of age have been decreasing since 2011.
- Maybe that’s due to increased awareness (both physician and parent) about how often some common problems like ear infections are viral and don’t need antibiotics.
Some good news. Some concerning news. Lots of room for improvement….and an indication of the need for more extensive antimicrobial stewardship programs.
The 2017 Canadian Antimicrobial Resistance Surveillance System report was just released, and as always it contains a lot of interesting data. Some are interesting, some are concerning, some are encouraging.
I’m not going to try to distill a 90 page report into a quick blog post, so I’ll cover some highlights separately. Let’s start with the Antimicrobial Use in Animals section. Here are some highlights (and some comments).
In 2016, ~1 million kgs of medically important antimicrobials were distributed for sale in Canada.
- This misses some antibiotics that get used via loopholes, but those are being closed and this number is probably a pretty good overall estimate.
- The great news…that’s 14% lower than 2007 and 17% lower than 2015
600,000 kg of ionophores and chemical coccidiostats were also distributed.
- These are often combined with other antimicrobials (sometimes to make things look scarier) but they are irrelevant from antibiotic-resistance and public health standpoints. So, it’s good to see them separate (and to essentially ignore them).
99% were intended for food animals, on a per kg basis.
- This is always hard to interpret and sometimes leads people to think that companion animals are irrelevant. We have to be a bit wary focusing just on per kilogram data (1 kg of antibiotic treats a lot more Chihuahuas than cattle). The main antibiotic classes used in companion animals were cephalosporins, beta-lactams and trimethoprim-sulfa, all drug classes of high importance.
- What this shows to me is that we can have a huge impact on overall use focusing on food animals. However, the drugs that are used in pets are often the same as those used for serious infections in people, and we share bugs readily with our pets. So this numbers shouldn’t be taken as an indication to ignore them.
Fluoroquinolones decreased by 56% from 2015 to 2016.
- Wow. That’s great, since this is one of the biggest classes we’re worried about. They’re important drugs (for both humans and some animal species) but are prone to overuse.
Most of the distributed antibiotics were those intended for use in feed, accounting for 76% overall. On the opposite end of the spectrum, intramammary drugs (used for mastitis in cattle) accounted for <1%.
When everything is put together on a per kg basis, 78% of antimicrobials distributed or sold in 2016 were for food animals, 20% were for humans, 1% for crops and 1% for companion animals.
- Again, be somewhat wary of crude kg numbers (since the relevance of a kg of tetracycline is probably much, much less than a kg of a fluoroquinolone) and there are approximately 19 times more animals in Canada (excluding farmed fish) than humans, but they give some idea of how we use antimicrobials in this country and they give us numbers for comparison over time. The 2nd figure below is an interesting on to think about.
Some people will take these numbers and use them to spin certain agenda. However, we’re better off using them as the basis for more surveillance, more interventions and more research to reduce and improve use of antibiotics in Canada, whatever species they go into.
We’ll kick of World Antibiotic Awareness Week with a crossword. Test your own antibiotic awareness. Answers will be posted later in the week.
Puzzle can be downloaded here: World Antibiotic Awareness Week Crossword Puzzle
The World Health Organization released new guidelines on the use of ‘medically important antimicrobials’ in food animals. Here’s a list of their recommendations, along with the strength of recommendation and quality of evidence.
- We recommend an overall reduction in use of all classes of medically important antimicrobials in food-producing animals (Strong recommendation, low quality evidence)
- We recommend complete restriction of use of all classes of medically important antimicrobials in food-producing animals for growth promotion (Strong recommendation, low quality evidence)
- We recommend complete restriction of use of all classes of medically important antimicrobials in food-producing animals for prevention of infectious diseases that have not yet been clinically diagnosed (Strong recommendation, low quality evidence)
- We suggest that antimicrobials classified as critically important for human medicine should not be used for control of the dissemination of a clinically diagnosed infectious disease identified within a group of food-producing animals (Conditional recommendation, very low quality evidence)
- We suggest that antimicrobials classified as highest priority critically important for human medicine should not be used for treatment of food-producing animals with a clinically diagnosed infectious disease (Conditional recommendation, very low quality evidence).
They included 2 “Best Practices statements
- Any new class of antimicrobials or new antimicrobial combination developed for use in humans will be considered critically important for human medicine unless categorized otherwise by WHO.
- Medically important antimicrobials that are not currently used in food production should not be used in the future in food production including in food-producing animals or plants.
One thing that stands out is the low quality of evidence. That doesn’t mean recommendations shouldn’t be made. Important decisions sometimes have to be made before the evidence is solid. However, we need to make sure the evidence follows. Much of what’s stated above is common sense, to a degree; however, sometimes things that make sense don’t actually turn out to be completely true. That’s one of the reasons CANresist is being developed, to help get the evidence and help translate both best practice and evidence based guidelines into action.
This topic’s huge, and there’s always a risk of trying to oversimplify the problem or solutions.
However, some solutions for some issues might be fairly straightforward. Whether it’s on a farm, in a hospital or in a doctors office, there are situations where I think it’s widely accepted we don’t need to use antibiotics, yet for various reasons they still get used. Getting over those barriers sometimes requires a combination of medicine, behavioural science, communications, psychology, economics and a range of other fields. Sometimes, though, the answer seems fairly simple.
A paper published in The Veterinary Journal showed how use of a simple treatment algorithm designed to be used by farmers results in an 80% reduction in antibiotic use in diarrheic dairy calves, with no impact on calf health.
That’s just one condition in one species, but it shows that there are some “low hanging fruit” that we might be able to pick.
Reference: DE Gomez, LG Arroyo, Z Poljak, L Viel, JS Weese. Implementation of an algorithm for selection of antimicrobial therapy for diarrhoeic calves: impact on antimicrobial treatment rates, health and faecal microbiota.
As World Antibiotic Awareness Week approaches, think about these miracle drugs and how they have changed our lives.
If you’re a prescriber, think about the last patient you treated and what would have happened without effective antibiotics.
Think about the last time you or a loved one was treated with an antibiotic and how important it was
Let us know on Twitter (@CANADAresist) #mylastantibiotic