Administering unnecessary antibiotics to critically ill coronavirus patients could worsen drug resistance, experts have warned.
Antibiotics – which only work against bacterial infections – are unusual in that the more the drugs are taken, the less effective they become.
Severely ill coronavirus patients can develop additional infections, like bacterial pneumonia, worsening their complications. The risk of this occurring has prompted some medics to prescribe antibiotics as a precaution.
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Writing in The Lancet Microbe, a team of UK scientists has revealed bacterial infections affected around one in 10 (12%) people hospitalised with the coronavirus during the UK's first pandemic wave.
The use of antibiotics was "high", with them administered to up to 85% of patients.
"In making any assessment of the use of antimicrobials in the treatment of COVID-19 [the disease caused by the coronavirus] patients, it is essential to acknowledge that clinicians in the UK – and worldwide – have been battling a global medical emergency," said lead author Dr Antonia Ho, from the University of Glasgow.
"Antimicrobials" is a broad term for drugs that work against different pathogens, like bacteria and fungi. Less than 1% of the Lancet study's patients were given anti-fungal drugs, which also have resistance concerns, with the remainder being prescribed antibiotics.
"Given the unprecedented challenges posed by the pandemic – particularly during its early stages when admitted patients were very sick, effective treatments were limited and the role of possible co-infections unknown – it is unsurprising that doctors would prescribe antimicrobials," said Dr Ho.
"However, we now know bacterial co-infection is uncommon in patients with community-acquired COVID-19.
"Since antimicrobial resistance remains one of the biggest public health challenges of our time, measures to combat it are essential to help ensure these life-saving medicines remain an effective treatment for infection in years to come."
Antibiotic resistance was a concern before the pandemic.
Over the years, many medics have mistakenly doled out antibiotics to treat viruses. Even when correctly prescribed, some patients fail to take the drugs as instructed, giving the underlying bacteria a better shot of developing resistance.
Pre-coronavirus, at least three in 10 (30%) of the antibiotics prescribed in the US were "unnecessary". As a result, more than 2.8 million antibiotic-resistant infections arise every year, killing over 35,000 Americans.
The World Health Organization has called antibiotic resistance "one of the biggest threats to global health".
So-called "superbugs" like methicillin-resistant Staphylococcus aureus (MRSA), Clostridium difficile (C diff) and some gonorrhoea strains are already not responding to once-effective antibiotics.
UK guidelines advise against the use of antibiotics in COVID patients "without specific evidence of bacterial infection".
Nevertheless, previous studies have suggested the drugs have been widely administered amid the pandemic. These studies were generally small and of low quality, however.
To learn more, the UK scientists analysed over 48,000 coronavirus patients who were admitted to 260 hospitals in England, Scotland or Wales between 6 February and 8 June, 2020 – the UK's first wave.
Of these patients – average age 74 – 8,649 underwent blood and respiratory tests, of whom 1,107 (12%) were found to have "COVID-19 related respiratory or bloodstream bacterial infections".
Bacterial co-infections, defined as those that occur before a patient is admitted to hospital, are "far more common" with severe flu, affecting nearly a quarter (23%) of cases.
When bacterial infections were detected in COVID patients, just over seven in 10 (71%) were considered to be "secondary", defined as the pathogen being acquired more than two days after hospital admission.
These secondary infections were generally not COVID-related, but commonly come about during a hospital stay, particularly when in intensive care.
Among the patients with the necessary data available, 37% were prescribed antimicrobials by a doctor or pharmacist before being admitted to hospital. More than four in five (85%) then received at least one antimicrobial during their hospital stay.
"While some COVID-19 patients will require antibiotics, mostly for secondary infections which develop after admission to hospital, our data show not all COVID-19 patients should be prescribed antibiotics," said Dr Ho.
"The longer someone is in hospital, particularly if they are in critical care, the more vulnerable they are to develop secondary infections.
"These should continue to be monitored, however, the bugs we identified are similar to those found in patients with hospital-acquired infection and not specific to COVID-19."
Watch: Antibiotic resistance amid the pandemic
Based on their results, the scientists recommend "antimicrobial stewardship interventions" be implemented amid the pandemic.
"We only have safe surgery and medical cures for many life threatening conditions because antibiotics were discovered and mostly still work," said co-lead author Professor Calum Semple, from the University of Liverpool.
"Overuse of antibiotics needs to be avoided to prevent emergence of resistance.
"When the current threat from COVID-19 subsides, the problem of antimicrobial resistance will remain a threat."
As well as avoiding antibiotics in patients who do not have a confirmed bacterial infection, the scientists recommend the drugs be "tailored", rather than relying on "broad-spectrum" medication.
Medics are also encouraged to discontinue antimicrobials if a co-infection is later deemed to be unlikely or if tests confirm the patient does not have a bacterial infection.
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The scientists have acknowledged co-infections are difficult to diagnose, particularly during a pandemic, with fewer than one in five (17%) of their study's patients undergoing blood and respiratory tests to look for the pathogens.
Nevertheless, co-author Dr Clark Russell – from the University of Edinburgh – said: "Our findings add much-needed depth to our understanding of how antimicrobials have been used in the treatment of patients with COVID-19 and how antimicrobial usage could be optimised.
"Prioritising and incorporating existing antimicrobial stewardship principles into care plans could help to prevent a rise of drug-resistant infections becoming a longer-term sequela of the pandemic.
"Our study looked at only the first pandemic wave in the UK, so it is important future studies assess antimicrobial usage later in the pandemic, both in the UK and other parts of the world."
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