This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.
Amoxicillin (a narrow-spectrum antibiotic) was as effective as co-amoxiclav (a broad-spectrum antibiotic which targets a wider range of bacteria) for people admitted to hospital with pneumonia, regardless of its severity. Research found that 30-day death rates were similar whether people received co-amoxiclav or amoxicillin.
The findings will encourage clinicians to follow guidelines and prescribe amoxicillin for low- or moderate-severity community-acquired pneumonia. The researchers say this could help reduce the spread of antimicrobial resistance. More research is needed before guidelines could be changed to recommend amoxicillin for severe pneumonia.
More information about pneumonia can be found on the NHS website.
The issue: are narrow-spectrum antibiotics effective for severe pneumonia?
Infections caused by bacteria that are resistant to antibiotics can be difficult to treat. Resistance is increased by using antibiotics that work on many types of bacteria (broad-spectrum antibiotics such as co-amoxiclav). To limit the spread of resistance, National Institute for Health and Care Excellence (NICE) guidelines recommend that clinicians use this class of antibiotics only when essential.
Pneumonia is an infection of the lungs, usually caused by bacteria. Symptoms include a cough, shortness of breath, and chest pain. Each year in the UK, 5 to 10 in every 1000 adults develop community-acquired pneumonia. Most recover in 2 to 4 weeks, but older people and those with heart or lung conditions are at risk of serious illness and hospital admission.
NICE recommends amoxicillin (a narrow-spectrum antibiotic) for low- to moderate-severity pneumonia. Co-amoxiclav (a broad-spectrum antibiotic) is recommended only for severe pneumonia. However, many people with non-severe pneumonia are prescribed co-amoxiclav when they arrive at hospital. In this study, researchers compared co-amoxiclav with amoxicillin for people arriving at hospital with community-acquired pneumonia.
What’s new?
Researchers analysed the electronic health records of 4586 adults (aged 16 and over) admitted to hospital with pneumonia in Oxfordshire between 2016 and 2023. Most (96%) were White, half (52%) were male, and their average age was 79 years. 3167 received co-amoxiclav and 1419 received amoxicillin 12 hours prior to or up to 24 hours after their admission.
As expected, people with the most severe pneumonia, and with other health conditions, were more likely to be prescribed co-amoxiclav. The researchers accounted for such differences to compare people who were similarly unwell but received different treatments. People in one treatment group were matched and compared to someone with similar risks (such as pneumonia severity) in the other group.
30 days after admission, the researchers found:
- a similar risk of dying whether people were prescribed co-amoxiclav or amoxicillin
- taking additional antibiotics (for instance, clarithromycin or doxycycline to treat other rarer causes of pneumonia) did not change the risk of death within 30 days.
Why is this important?
The findings support NICE guidelines in encouraging clinicians to use amoxicillin for mild to moderate pneumonia. In this study, 3490 (76%) of the patients studied had mild to moderate pneumonia. More widespread use of amoxicillin, a narrow-spectrum antibiotic, could help reduce the spread of antibiotic resistance.
NICE guidelines suggest reserving co-amoxiclav for people with severe pneumonia. The study found that clinicians tended to follow this guideline; people with severe disease, and other conditions, were more likely to be prescribed co-amoxiclav. However, when results were adjusted for this difference, amoxicillin was as effective as co-amoxiclav at treating community-acquired pneumonia, at all levels of disease severity. But this study was not a randomised controlled trial, and this finding is not conclusive.
What’s next?
A randomised controlled trial is needed to directly compare amoxicillin with co-amoxiclav for people with severe pneumonia, the researchers say. They also call for better diagnostics and tools to identify those most in need of broad-spectrum antibiotics, such as people at risk of antibiotic-resistant or atypical infections.
Can I act on this research?
You may be interested to read
This is a summary of: Wei J, and others. No evidence of difference in mortality with amoxicillin versus co-amoxiclav for hospital treatment of community-acquired pneumonia. Journal of Infection 2024; 88(6): 106161.
World AMR Awareness Week takes place from 18 to 24 November each year.
Funding: This study was funded by the NIHR Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance at Oxford University.
Conflicts of Interest: No relevant conflicts were declared. Full disclosures are available on the original paper.
Disclaimer: Summaries on NIHR Evidence are not a substitute for professional medical advice. They provide information about research which is funded or supported by the NIHR. Please note that the views expressed are those of the author(s) and reviewer(s) at the time of publication. They do not necessarily reflect the views of the NHS, the NIHR or the Department of Health and Social Care.
NIHR Evidence is covered by the creative commons, CC-BY licence. Written content and infographics may be freely reproduced provided that suitable acknowledgement is made. Note, this licence excludes comments and images made by third parties, audiovisual content, and linked content on other websites.
