A new type of antimicrobial resistance to fluoroquinolones, a group of antibiotics that is very important to both human and animal health, has emerged in the Netherlands and other European countries over the last decade.
This is one of the conclusions of a thesis entitled ‘Plasmid mediated quinolone resistance in Enterobacteriaceae’ by Kees Veldman, a researcher at CVI. Veldman studied a specific type of resistance known as ‘Plasmid Mediated Quinolone Resistance’ (PMQR). PMQR was first discovered in human gut flora in the United States in the late 1990s. Veldmans research shows that this type of resistance is also present in gut flora of farm animals in Europe. In the Netherlands, PMQR was detected in gut flora of humans and farm animals.
Resistance to fluoroquinolones in bacteria that can cause infections is a risk to public health. It can be caused by minor changes in the DNA (chromosomal mutations) of bacteria, but also by PMQR genes present on plasmids (small transferable pieces of circular DNA), which are able to spread rapidly between bacteria. Although bacteria with PMQR genes are less susceptible to fluoroquinolones, they are not untreatable. However, these resistant genes are considered clinically relevant because they can play a role in the development of more serious clinical resistance to fluoroquinolones.
In his research, Veldman describes the first Salmonella and E. coli bacteria with transferable quinolone resistance in farm animals and humans in the Netherlands. Veldmans research shows that in the Netherlands, PMQR is only rarely found in the gut flora of humans and farm animals. However, in recent years, this type of quinolone resistance was more frequently observed in animals to which more quinolones and fluoroquinolones were administered (broiler chickens and veal calves). PMQR is also rarely found in Salmonella and E. coli from the gut of farm animals in a number of other European countries, mainly in broilers and turkeys.
More research is needed to determine to what extend the increase in PMQR will lead to an increase of clinical resistance to fluoroquinolones in the future. Veldmans research also revealed that multiresistant bacteria (with PMQR) are being imported into the Netherlands via human as carriers and contaminated fresh herbs from outside Europe. This shows that antibiotic resistance is a global problem, which needs to be tackled on an international scale.