• 18 Feb 2020
  • 19 min
  • 18 Feb 2020
  • 19 min

Justin Coleman interviews Kirsty Buising about the latest updates from Therapeutic Guidelines on antibiotics.


Welcome to the Australian Prescriber Podcast. Australian Prescriber, independent, peer-reviewed and free.

Hi and welcome to this Australian Prescriber podcast. I'm Dr Justin Coleman, a GP on the Tiwi Islands, north of Darwin, and author of the RACGP Choosing Wisely: Recommendations Around Use of Antibiotics in General Practice.

When I was a first-year Melbourne Uni med student sometime last millennium, our ancient microbiology lecturer made about the only truly exciting announcement of his course, inviting us each to come down the front and pick up a free book. That book was the original Antibiotic Guidelines, which I believe was their first-ever publication from the Therapeutic Guidelines series, now known as eTG, although, of course, the E didn't exist back in those days.

But move forward 33 years and eTG has become a publishing phenomenon and someone has invented podcasts, and I give you not a free book, but a free 15 minutes listening to what's new in the 16th version of that same book.

Now back in 1987, we thought that antibiotic resistance was a quirky beta-lactamase thing that some bugs had figured out in response to penicillin. But now, antibiotic stewardship will no doubt dominate today's discussion.

In fact, today, my expert guest is a steward extraordinaire, Dr Kirsty Buising. Kirsty is an infectious diseases physician at Royal Melbourne Hospital and deputy director of the National Centre for Antimicrobial Stewardship. So welcome, Kirsty.

Thanks, Justin. It's good to be with you.

For the first time ever, I think it won't be a published book and it will be an online book. I think that is reflective of the way things are moving these days. It's live evidence and it gives the chance to update things more rapidly, rather than having to wait. I guess, with antibiotics, it changes almost as fast as any other field.

Yes, that's right. I mean bugs evolve, don't they? And the epidemiology of the types of infections that we're seeing or the new challenges that come along from an infection point of view are constantly evolving. I guess in addition to that, there’s new evidence being published all the time.

Yes. Well, sadly, I’ve actually thrown out about three house moves ago, my original copy, but it’s now probably a collector’s item.

It would be.

But your expertise is on stewardship of antibiotics. Well, I call them antibiotics, antimicrobials, I guess. There are some strategies at the start of the book talking about the fact that we should specify the duration of therapy and default to not giving repeats. I do tell my registrars when they come to the practice to make sure the software automatically defaults to no repeats for antibiotics. Because I think really to give an antibiotic repeat should be an active decision made with the patient in front of you. Is that right?

Yeah, absolutely, so it sounds like you're on top of this. The whole broader view of stewardship is that we treat antibiotics as a precious resource and we use them judiciously. We use them when we really need them. When we really need them, we use the duration that there's evidence to say we need to use and we try to avoid unnecessary doses.

One of the things in the new version of the Therapeutic Guidelines is the authorship group have been really careful to specify the evidence-based duration that's required for each of the indications that are in there. Shorter durations are in trials having equal efficacy to some of the old traditional durations that might've been just based on the fact that there were seven days in a week or 10 fingers on our hands.

I've never actually thought of it, but I like it. The Bible has 12s in it and hands have 10 in it and weeks have seven in it and they tend to be the number of antibiotics in a packet.

One thing that strikes me when you mentioned that is when I do talk to or write an article often about antibiotic use, a lot of GPs do come back and say, "Well, in the end, it's the agricultural industry that is responsible for the resistance and so what we do is a drop in the ocean."

I guess in the role that I have in the National Centre for Antimicrobial Stewardship, we're a one-health research group and that means that we have animal health experts working alongside human health experts and so I've learnt a lot about animal health antibiotic use. I think the important learning there is that, in the broader context, the Australian food industry and veterinarians are not prescribing huge volumes of antimicrobial drugs. In fact, relative to the rest of the world, we're a very low prescriber. The classes of drugs that are being used there in general are certainly not high-risk drugs that we are very dependent on in human health.

So I think we've moved beyond that finger-pointing back and forward of vets blaming doctors and doctors blaming vets and just saying, "Look, collectively, we all live in one world. We all acknowledge that antimicrobial resistance transmits from animals to humans to the environment and we've got to work collaboratively around this. All of us value the precious resource that antimicrobials are."

Dr Kirsty Buising, I like you already. You've got that we are one, that collective feel. I think you're right. It is something we can only all tackle together.

Let's move off the bigger picture down to more specifics now, about what's new in these guidelines and how some of these things play out in clinical practice with the person in front of us. And we’ll start with respiratory infections. There's a section there which has been updated on pharyngitis and tonsillitis. In fact, there's a number of things with the respiratory tract where evidence comes out that, in fact, if you don't use antibiotics, people still often tend to get better.

Yeah, you're absolutely right. In the pharyngitis space, a recognition that the vast majority of cases are viral and will get better without antibiotics and that even in those that may well be caused by bacteria, that most of them will still improve without specific antibiotic therapy.

The recognition that bronchitis is one of the really common conditions that people will present to a GP with, and then ask the question, "Do you think they need some antimicrobials?" We came to understand that, in fact, the previous versions of the Therapeutic Guidelines hadn't really addressed bronchitis very well and that it probably deserved some dedicated information there.

It's typical for the cough to go on for two or three weeks and so that idea that, "Oh, if the cough is there for more than a week, I might need some antibiotics" probably doesn't hold true. The recognition that the vast majority are, indeed, caused by viral infections. Some recommendations about symptomatic management of the cough in bronchitis to give people information about something they can do to help themselves feel better without needing to reach for an antibiotic.

What I found quite helpful, too, was some description around how you might differentiate, clinically, bronchitis from pneumonia. Some simple things. Breathlessness is far more likely in pneumonia, whereas in bronchitis it's predominantly cough, which may or may not be productive of sputum and may or may not be accompanied by wheeze.

But once a patient is starting to have trouble breathing and getting breathless, the clinician might start to think this could be pneumonia. People with pneumonia may have tachycardia at rest or tachypnoea at rest, whereas patients with bronchitis really shouldn't have that.

Then there's the clinical examination of the chest and an appreciation that people with bronchitis, well, they can have crepitations that if you get them to take a big breath that those creps will generally clear, whereas fixed crepitations that aren't changing with respiration make you much more anxious that the person might have pneumonia.

We well and truly appreciate that not everyone in general practice needs to be sent for a chest x-ray.

Sorry, I'd go so far there as to say that most with respiratory infections shouldn't have a chest x-ray because I think that would be poor practice in general practice if there's no suggestion they are sick enough to need to go to hospital.

Sure, sure.

I think it's very important those words and terminology because I know as a GP you feel when you type in the notes, if you use a word like chest infection, there's sort of this implication that you then should do something about it. So it's sort of nice to be able to have that bronchitis does have that implication that it's viral.

In the same ways many years ago if you wrote pharyngitis, you felt that if you didn't give an antibiotic, someone would come back and look at your notes and say, "Well, you've said they've got pharyngitis and now why aren't you giving an antibiotic?" So I think the naming is quite important.

Yeah, yeah. I sort of think about it in my mind when I'm thinking about bronchitis, I'm thinking it's the airways, whereas when I'm thinking about pneumonia, I'm thinking it's the alveoli full of fluid or pus.

I think a classic is acute otitis media where, in the past, someone would've been horrified if you ever sort of red bulging drum or something and didn't use an antibiotic, they would consider you almost negligent. But I think some of the Scandinavian countries led the way cutting down on antibiotic use for that and Australia has certainly caught up over the last perhaps 10 years or so.

Certainly infants need it and Aboriginal and Torres Strait Islander people. So where I work, we do use plenty of antibiotics for otitis media, which overlaps hugely with chronicity, chronic ear problems and other children of high risk of complications.

But for kids who are older than two years and systemically not too unwell can still have a fever, I think there's more and more move towards not using an antibiotic.

Completely agree with you. I think the guidelines for a lot of conditions are moving toward giving permission for clinicians to say, "Watch and wait," and that the vast majority of these will get better by themselves and regardless of whether or not, whether they are viral or bacterial indeed, some of these. They're probably mixed pathogenesis in it a lot of these. But if you sit tight the vast majority of these kids will get better in two or three days, and it's giving GPs and parents the permission to not jump in there with antibiotics.

I guess you highlighted the Scandinavian countries. In the antimicrobial stewardship world we sort of hold them up as the countries that have led the way and where they really managed to reduce antibiotic consumption is, interestingly, in children less than five years of age. So there's a strong suspicion that we do overuse antibiotics, particularly in those little kids.

They are the medical world's heroes, aren't they, those Scandinavians? Thank goodness we can still be better at them at surfing and cricket or something like that. But there's also the emerging concept of shared decision-making because I guess a lot of these things aren't really black and white. It's not as if we could ever really say, "Look, in this instance, 0% of people will need an antibiotic. And in this instance, 100% will." Often there's pros and cons depending on the individual.

The Therapeutic Guidelines have provided some hyperlinks to some tools that GPs may find helpful to guide the discussion that they might be having with a patient or their family, their parents.

Medicine is not perfect and no clinician can make an absolute guarantee that this person does or does not need antibiotics. But these shared decision-making tools just lay a little bit of that information out explicitly on the screen. Or if you choose to print them out, it'd be on paper that you can sit with your patient and guide them through.

Yes, and we’re even moving away from necessarily having a black-and-white virus versus bacteria talking in the Ulcer and Wound Guidelines we were talking about swabbing all the muck that's popping out of an ulcer almost always grows some sort of bacteria, but it doesn't necessarily mean they have to use an antibiotic.

And I noticed with acute sinusitis, it's not necessarily so important the specific question, "Are there any bacteria in the sinus?" What's important is, "What is the difference in the outcome?"

One of the things I get quite interested in is explaining the natural history of an illness to a patient. Because I think if they're empowered, they know what to expect. They're much less likely to panic and to want a tablet that may be completely unnecessary.

Importantly, I'm sure you found, Justin, because I've certainly found with my patients, that a lot of them are concerned about not only the short term, but also the potential long-term impact of taking antibiotics. Some of them do worry about, "What's happening to my good bacteria?" And patients become more cognisant of the fact that antibiotics are not harmless, that idea that, "Oh, it won't hurt."

Yeah, and I think it's a credit to various members of the medical profession that that conversation has got out there in the public arena.

I did want to move on now to cystitis, so urinary infections. In my knowledge, it was one of the first ones ever where it was shown that, for example, three days of antibiotics in an uncomplicated urine infection was every bit as good as seven days. Some of the studies have come out to go even further than that and saying we don't always need an antibiotic at all. Is that right?

Yeah. So there were a couple of really interesting papers from Europe in recent years that took young women without other complications, so not pregnant and not unwell with other comorbidities, and just looked at whether it was a safe thing to do not to give them antibiotics when they presented with uncomplicated cystitis. In fact, there was very little difference in the rate of symptom improvement and the rate of progression to pyelonephritis. If she has an episode of cystitis and you don't give her antibiotics, the likelihood that she'll progress to pyelonephritis is actually really, really low. It was something in the order of 1 or 2% from memory, so it's not an unsafe thing to do.

So in terms of the treatment of cystitis or urine infections, have there been any changes to the first-line antibiotics used?

The first-line antibiotic recommended is still trimethoprim. I am aware, and GPs probably have noticed, that there is a rate of resistance in the community amongst our common E. coli and it probably runs at roughly about 20%. But for a condition that is a reasonably low-risk condition, we still think that 80% likelihood of empirically covering the pathogen is a very reasonable first-line recommendation.

But, interestingly, the second-line recommendation has now become nitrofurantoin. That's a drug that fell out of favour because of side effects that occurred when it was used long term for patients as a prophylactic drug. Those side effects are very, very unlikely, extremely, extraordinarily rare if it's used for the very short five-day course that's needed for acute cystitis. And susceptibility to nitrofurantoin has been really well retained amongst the urinary pathogens.

Cephalexin and amoxicillin/clavulanate have really dropped out of first-line recommendations for cystitis.

Gosh, nitrofurantoin. I feel personally proud for that maintaining its impact because I can't remember using it for many years, but clearly I will be going through it more now. I'm talking with Dr Kirsty Buising, the infectious diseases physician at RMH in Melbourne. One of your particular areas of interest is in penicillin allergy and penicillin hypersensitivity. I do notice that also crops up with some new teachings in this 16th edition of Antibiotic Guidelines. Can you talk us through that?

Sure. I guess there's been increasing interest in the area of penicillin hypersensitivity in recent years and I guess it's driven by a recognition that penicillin allergy labels are actually really common. It leads to people not getting first-line recommended treatment, which is usually the treatment that has the best evidence and the most likelihood of efficacy. Instead, they're going to second- or third-line treatment, so it's a bad thing to have a penicillin allergy label.

There's been recognition that oftentimes they're applied to patients who've actually only had side effects of the medication, rather than an allergic reaction, so people who tell you they're allergic and then when you question them, it turns out they had nausea or diarrhoea or a headache or something. In those situations, we really want to encourage all clinicians to do is to remove the label of penicillin allergy from them so that they can have first-class, first-choice drugs.

But for that group that do have an allergy, a true allergy, there's some more nuanced discussion around the different types of allergy. They can be immediate or delayed reactions and that there can be severe or non-severe reactions and that the risks of exposing people to penicillins or penicillin-like drugs are categorised in the new guidelines based on those four categories.

I agree. It's very frustrating when people have a possible penicillin allergy from 40 years ago and it really limits our prescribing ever since. I also think one of the issues is the prescribing software we have, which tends to only allow an allergy or not.

Dr Kirsty Buising, thank you very much for your comments as we, together, make the world a better place and try to help individuals, while not increasing the antibiotic resistance around the tracks.

Thanks, Justin.


My guests' views are their own and don't represent Australian Prescriber and my views are certainly all mine.