An increase in temperature and increasing resistance to antibiotics may be related, according to a new analysis.
A study published in the journal Eurosurveillance between 2000 and 2016 didn’t establish a causal relationship between the two health threats, but the results suggest that rising average temperatures support the growth of antibiotic-resistant bacteria.
The researchers, led by Mauricio Santillana and Sarah McGough, analyzed data from more than four million patients in 28 European countries in the Boston Children’s Hospital Health Informatics Program, according to the Phys.org science-educational news portal.
They examined how the antibiotic resistance of three common bacteria (Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus) changed over time. Data on temperature values in the countries were also collected from European and American sources.
“Our study is the first to show that in European countries with higher minimum temperatures, there have been several marked increases in antibiotic resistance over the 17 years studied,” said Santillana, who also works at Harvard University’s Faculty of Medicine and Public Health.
Based on the results, antibiotic resistance increased faster in those southern European countries – Spain, Portugal, Romania, Italy, whose minimum temperature values were 10 degrees higher than in the north, including Sweden, Finland, Norway.
Growth ranged from 0.33 to 1.2 percent per year in the countries, taking into account population density and the different antibiotic use in each country.
The relationship was true for all four classes of antibiotics and for two of the three bacteria analyzed. In the case of S. aureus, resistance has declined, which scientists attribute to efforts across Europe to curb methicillin-resistant S. aureus or MRSA.
The researchers acknowledged that both temperature and resistance may have increased independently, but a correlation is also possible. Laboratory experiments have shown, for example, that bacteria multiply better under warmer conditions, which can promote the spread of resistant strains. Other studies have suggested that higher temperatures favor the transfer of antibiotic-resistant genes between bacteria.