Berlin: Antibiotic resistance in bacteria spreads much faster and with more varied mechanisms than previously thought, say scientists who suggest exercising caution in the use of the drugs. By studying fish raised in aquaculture, researchers from the Helmholtz Zentrum Munchen in Germany, the University of Copenhagen in Denmark and the University of Campinas in Brazil have shed new light on the mechanisms by which antibiotic resistance genes are transferred between bacteria.
According to the study published in the journal ‘Microbiome’, those mechanisms are more varied than previously thought. “In the past 70 years, the use of antibiotics in human and veterinary medicine has steadily increased, leading to a dramatic rise in resistant microorganisms,” said Michael Schloter, head of the Research Unit for Comparative Microbiome Analyses (COMI) at Helmholtz Zentrum Munchen.
It is especially alarming that many microorganisms are resistant not just to one antibiotic, but to a whole range of different substances, said Schloter. “This poses particular problems in the treatment of infectious diseases. We therefore set out to discover the mechanisms responsible for resistance development,” Schloter said.
To this end, researchers investigated fish raised in aquaculture. Specifically, they studied Piaractus mesopotamicus, a South American species known as pacu that is often raised in aquaculture. The fish received the antibiotic florfenicol in their food for 34 days. During this time and after the application period, the researchers took samples from the digestive tract of the fish and looked for relevant genetic changes in the gut bacteria.