Urinary superbugs: Are we going about it wrong?

David Lam

29/03/2024 11:10:09 AM

A new study investigating rates of antimicrobial resistance in aged care highlights the need for a potential overhaul of antibiotic guidelines.

Aged care resident receiving antibiotics
Up to 30% of E. coli identified in aged care as part of a recent study was resistant standard treatment with trimethoprim.

Current guidelines for the treatment of UTIs may be increasingly ineffective amid alarming rates of antibiotic-resistant E. coli found in testing, according to new research from the University of New South Wales (UNSW).
The study, published last week in Open Forum Infectious Diseases, is the largest of its kind in Australia and analysed more than 775,000 bacterial isolates from Australian community, hospital and aged care settings from 2016 to shed light on antibiotic resistance trends.
Co-author Associate Professor Li Zhang from UNSW’s School of Biological and Biomedical Sciences admits that even she was surprised by the study’s key findings.
Hospitals have long been considered the primary hotbeds for antibiotic-resistant superbugs and for generations, GPs and doctors from other disciplines have traditionally used trimethoprim as the first line empirical antibiotic for treatment of UTIs.
However, Professor Zhang’s study potentially turns both these presumptions on their head.
The new research suggests that prevalence of antibiotic-resistant E. coli in aged care facilities has now overtaken hospitals and an alarming amount – up to 30% – of these bacteria are now resistant to standard treatment with trimethoprim.
‘Firstly, I didn’t expect the antibiotic resistance to be so high to trimethoprim,’ Professor Zhang told newsGP.
‘Secondly, I always thought hospitals had the highest rates of resistant E. coli, but actually, in aged care it is even higher.’
UTIs represent a significant health burden in Australia and are among the top five most common causes of preventable hospitalisations across the country, according to the Australian Institute of Health and Welfare.
The One Health antimicrobial resistance economic perspective by the University of Technology Sydney showed they account for 2.62 million GPs visits per year and cost the health system an estimated $909 million annually.
Professor Zhang therefore advocates for a revision of current guidelines on the treatment of UTIs. At present, the Therapeutic Guidelines recommends that trimethoprim be used to treat uncomplicated urinary tract infections. However, this does not necessarily take into account that E. coli is increasingly resistant to this antibiotic.
Furthermore, the Therapeutic Guidelines do not make any distinction between which antibiotics should be used in aged care, which again fails to account for the increased prevalence of superbugs in these settings.
‘Personally, I don’t think trimethoprim should be the first line anymore for community and aged care facilities and we should also look at specific guidelines for aged care,’ Professor Zhang said.
The study indicates that resistance to nitrofurantoin in E. coli is in the order of 10% which is far less common than to trimethoprim. This raises the question as to whether Australian guidelines should actually be recommending the use of nitrofurantoin as the first line antibiotic treatment for UTIs, as has now become the practice in the United Kingdom.
However, a relatively higher rate of allergic reactions and a more limited body of evidence around the drug’s use have traditionally made change difficult.
Dr Zhang believes more research needs to be done to expand upon the findings of the study and inform policymakers.
‘We know that the prevalence of antibiotic-resistant E. coli is the highest in aged care. The next step is to ask why,’ she said.
‘Is it because older people in aged care facilities have visited hospitals and acquired the resistant UTI there? Or is it because antibiotic resistant strains are circulating in the aged care facility itself? Is it even perhaps because aged care residents are typically an older population who may have had a lifetime of repeated exposure to antibiotics?
‘We will now want to look at the genomes of the isolates in our study and analyse their antibiotic-resistant genes to find the bacteria’s source. This will be very useful for policy making to control antibiotic resistance.’
In general, antimicrobial resistance continues to be a major problem for aged care residents.
The most recent Antimicrobial Stewardship in Australian Health Care report states that three in 100 aged care residents in Australia have an infection at any one given time. Meanwhile, six in 100 are receiving antibiotics at any one point in time and between 50–80% of aged care residents receive at least one course of antibiotics per year.
Professor Paul Glasziou, a GP and Director of the Institute for Evidence-Based Healthcare at Bond University, agrees that use of nitrofurantoin instead of trimethoprim to treat UTIs could help reverse antibiotic resistance.
However, he also warns that we must be mindful of the specific side effects, for example, the increased risk of allergic reactions to nitrofurantoin when compared with trimethoprim. 
‘Resistance is reversible,’ he told newsGP.
‘Antibiotic resistance is a selection process rather than the development of new genes. So if you stop using a particular antibiotic, you reverse the selection process.
‘It is a trade-off though … how willing are you to accept the increased risk of allergy to improve resistance?’
Professor Glasziou also reminds us of the hidden complexity surrounding proper diagnosis of true UTIs and appropriate treatment with both medication and non-medication therapies. He ultimately calls for GPs to lead the treatment of UTIs.
‘Multiple studies show lower the rates of recurrent infections with good hydration, ingestion of cranberries and the use of hipprex,’ he said.
‘Many patients clearly need antibiotics for their UTIs; however, you need to confirm that it is a true UTI using microscopy and sensitivity testing, at least for the first episode.
‘One of the things that worries me about … pharmacists prescribing antibiotics for UTIs in Queensland, is there often hasn’t been a confirmation that there is a true infection and not something else such as urethral irritation.
‘That’s what GPs are for – and I’m not sure the pharmacists should be doing it.’
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Dr John Lamb   30/03/2024 8:49:53 AM

I’ve been concerned for years about asymptomatic aged care residents being diagnosed with UTIs and being treated with antibiotics on the basis of pyuria on routine dipstick results. Uncontaminated mid stream collection is almost impossible for many elderly people.

Dr Catherine Mary Regan   30/03/2024 10:13:00 AM

Interestingly in my early years as a GP 35 yrs ago I decided to check the sensitivities of all MSUs done by me to see how the local population compared to findings from the broad based main path company in town at the time. My recollection is that it was a bit different. A significant % was resistant to trimethoprim & amoxil (used at the time) - but it was restricted mainly to older pts (community sample) & recurrent UTIs. I had laboriously collected ages etc on handwritten sheet! This informed my prescribing for some time. Given issues with nitrofurantoin I tended to go keflex for older patients and trimethoprim for younger.

Dr Izabela Ostrowska-Kusiak   30/03/2024 1:47:33 PM

In my practice I have noticed EColi UTI resistant to commonly used Trimetoprim or Cephalexin if patient is allergic to sulfa drugs, and increased cases of UTI’s in elderly patients caused by different bacteria like Klebsiella resistant to penicillins, cephalosporins and sulfonamids requiring an authority scripts for Norflaxacin

Dr Mauricio Diaz Jaramillo   31/03/2024 12:00:27 AM

One may think this is a strong argument against indiscriminate AB prescribing by undertrained providers through pharmacies, and it is. Nevertheless, not only there isn't much that is "News" to presence of AB resistance in aged care, but the writer appears to ignore the fact that the solution to AB resistance isn't just to use yet another AB in a shotgun approach through a guideline (because this is what "guidelines" do).
I feel the "News" format to this bulletin lacks the clinical judgement necessary to the Medical profession, even if presented with scientific claims. It makes me feel disappointed every time, but how would one dare stop reading our very own RACGP publication? That would seem hardly defensible!.
Does anyone out there have any wise advice to manage my FOMO?

Dr Catherine Mary Regan   31/03/2024 2:12:30 PM

I went on to read the original article. It’s obviously interesting but it’s always a bit disturbing that a study so focused on mathematical models may subsequently be applied very broadly to clinical contexts with little nuance. It was interesting that it was noted that the resistance to amoxycillin decreased (statistically )during Covid - and yet it is quite obvious that the level of resistance is still clinically significant. In practice one assumes prescribing would also be influenced by other factors such as the age of the patient, patient gender, past history, comorbidities eg CKD and types of side effects.

Dr Liz Marles   3/04/2024 11:06:05 AM

This article does not adequately cover the complexities around antibiotic choice for urinary tract infection. It is unfortunate that Therapeutic Guidelines was not contacted for comment. Residence in an aged-care facility with a high prevalence of resistant bacteria is listed in Therapeutic Guidelines as a risk factor for multidrug-resistant infection, and the guidelines clearly indicate treatment options for such infections.

The UTI guideline is currently under review and will be republished later in the year.

Dr Eritabeta Wilson Maen   26/05/2024 3:02:25 PM

My anxiety or frustration continues to escalate with the ways antibiotics are being used , increasing the risk of developing antibiotics resistance, an imminent killer not in the far future.
Firstly the recommended antibiotic dosing in the Infectious disease guidelines is not aligning with the half life of the antibiotic.
The commonly used Keflex recommended dosing 2 tabs bd or tds or qid, I guess to ensure compliance
I have seen few cases of confirmed UTI sensitive to Keflex but not much improvement to the 1 gm bd dosing
Changing to q6 h eventually cured the the patient
Few cases been treated with alprim from the chemist but still symptomatic
This is a real battle as the MCS culture was not done creating uncertainty with the next step of management ie I have to guess what is the best antibiotic to use if is a resistance UTI.Collecting another MSU is not expected to have any success
So the simple clinical condition has become complicated, expensive and unsafe.