THE covid-19 pandemic may have led to a rise in antibiotic-resistant bacteria. While a modelling study suggests that Europe's various lockdowns resulted in a decline in cases of a pneumonia-causing bacterium between 2019 and 2020, the proportion of those that were resistant to antibiotics increased.
People with covid-19 may be at a greater risk of bacterial infections because fighting off viruses limits the immune system's ability to tackle invading bacteria. Confirmed or suspected bacterial co-infections may be treated with antibiotics, which can contribute to the bacteria becoming resistant to the drugs.
Aleksandra Kovacevic at the Pasteur Institute in France and her colleagues modelled how people interacted in and out of Europe's covid-19 lockdowns, alongside changes to the prescription of antibiotics between 2019 and 2020, and how these affected the bacterium Streptococcus pneumoniae's ability to evolve antibiotic resistance and its transmission in non-hospital settings.
The team also used data on the transmission of the original SARS-CoV-2 coronavirus and the extent to which it affects S. pneumoniae's ability to go from being carried asymptomatically to resulting in illness – the bacterium lives harmlessly in many people's throats, but can cause pneumonia and serious blood infections.
Within the model, the team simulated the planting of two coronavirus cases in a population of 100,000 people. On day 120 of the simulated outbreak, a 90-day wave of infections began. The model, which tracked changing levels of antibiotic-resistant and antibiotic-sensitive S. pneumoniae cases, spanned one year.
The team ran six scenarios through the model. Three included population-wide lockdowns, which reduced the spread of S. pneumoniae.
But in all six scenarios, the coronavirus wave was associated with a rise in the proportion of S. pneumoniae that was antibiotic-resistant (bioRxiv, doi.org/jw4k).
This could lead to more medical complications and hospitalisations, says team member Lulla Opatowski. But we don't know if higher-than-expected morbidities linked with antibiotic-resistant S. pneumoniae have occurred in the pandemic, says Scott Olesen at the US Centers for Disease Control and Prevention.
The situation could even be worse than the modelling suggests, as it only simulated S. pneumoniae in non-hospital settings, says Olesen.
It is also unclear whether similar results apply to bacteria other than S. pneumoniae.
We don't know if higher morbidities have occurred during the pandemic due to antibiotic resistance
This model indicates there were changing levels of antibiotic resistance among a bacterium that causes respiratory infections, but you would need different models to gauge resistance in a bacterium such as Escherichia coli, which mainly spreads via contaminated food, says Kovacevic.