Antibiotic-resistant bacteria may have become more of an issue amid the covid-19 pandemic. While a modelling study suggests that Europe鈥檚 various lockdowns resulted in a decline in cases of a pneumonia-causing bacterium from 2019 to 2020, the proportion of cases that were resistant to antibiotics increased.
People with covid-19 may be at a greater risk of bacterial infections because fighting off viruses hinders the immune system鈥檚 ability to tackle invading bacteria. Confirmed or even suspected bacterial co-infections may therefore be treated with antibiotics, which can contribute to the bacteria becoming resistant to the drugs.
Streptococcus pneumoniae lives harmlessly in many people鈥檚 throats, but can cause pneumonia and life-threatening blood infections, known as septicaemia, particularly among very young children, older people or those with certain medical conditions.
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at the Pasteur Institute in France and her colleagues modelled how Europe鈥檚 covid-19 lockdowns, the transmission of the original SARS-CoV-2 coronavirus and changes to antibiotic prescriptions from 2019 to 2020 all affected S. pneumoniae鈥檚 spread in non-hospital settings, as well as its ability to evolve antibiotic resistance.
They built a mathematical model using previously collected data on how SARS-CoV-2 and S. pneumoniae spread and the extent to which the virus affects the bacterium鈥檚 ability to go from being carried asymptomatically to causing illness.
The model also included information on antibiotic use and how people interacted when in and out of lockdowns throughout Europe.
Within the model, the team simulated planting 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 pandemic scenarios through the model, three of which included population-wide lockdowns. In these scenarios, the lockdowns reduced the spread of S. pneumoniae.
But in all six scenarios, the 90-day coronavirus wave was linked to an increase in the proportion of S. pneumoniae that was antibiotic-resistant, regardless of whether this bacterium was carried asymptomatically or caused ill health.
Higher rates of antibiotic-resistant S. pneumoniae could lead to more medical complications and hospitalisations, says team member at the Pasteur Institute. However, we don鈥檛 know if higher-than-expected morbidities associated with antibiotic-resistant S. pneumoniae have actually occurred amid the ongoing pandemic, says at the US Centers for Disease Control and Prevention.
Despite this uncertainty, the situation could be worse than the modelling suggests, as it only simulated S. pneumoniae in non-hospital settings, says Olesen. Further modelling is therefore needed to account for potential antibiotic resistance among people in hospital, who are more at risk of severe infections and more likely to be given antibiotics than the general population, he says.
New models are also needed to simulate the effects of recent SARS-CoV-2 variants and to do so in the context of restriction measures having largely been lifted globally. 鈥淭he model assumption that people with covid-19 will be quarantined is no longer correct in 2023,鈥� says at the European Centre for Disease Prevention and Control.
It is also unclear whether similar results apply to bacteria other than S. pneumoniae.
This model indicates how antibiotic resistance rates have changed among respiratory infections similar to S. pneumoniae, but you would need different models to gauge resistance in a bacterium such as Escherichia coli, which primarily spreads when contaminated food is eaten, says Kovacevic.
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