Wednesday, 11 March 2015

Antibiotic bacteria lurking in rivers



Rivers appear to be a significant source of antibiotic resistant bacteria, and have a consequential impact on the environment. New research into the river Thames has found numbers to be higher near waste water treatment works.

In 2013 Digital Journal reported that antibiotic-resistant bacteria had been isolated in specific spots along the Hudson river, from the Tappan Zee Bridge to lower Manhattan. The cause was linked to raw sewage being pumped into the water. Now similar research has uncovered the same trend in the U.K.

The finding is the outcome of a joint project between microbiologists working at University of Warwick's School of Life Sciences and the University of Exeter Medical School.

The research into the river Thames has discovered high numbers of antibiotic resistant bacteria and has shown that the numbers of such bacteria are highest close to water treatment facilities. Many of the bacteria recovered are from the class Enterobacteriaceae, a grouping that includes many human gut pathogens like Escherichia coli.

For the study, the microbiologists analysed water and sediment samples from 13 sites across the Thames river catchment and developed detailed models to predict the distribution of antibiotic resistant bacteria.

This supports the theory that high numbers of antibiotic resistant bacteria are released into the environment through human and agricultural use. With agriculture, the situation arises because of the administration of antibiotics to farm animals. This is done to increase the quality of meat. However, it is hard to avoid animal slurry from entering rivers, especially during times of heavy rain.

The results are important due to the concerns with the rise in antimicrobial resistant bacteria and the risks these organisms pose to human health (especially with those receiving hospital treatment.)

In terms of waste water treatment, it was found that not all water processing plants are the same. Those that use a third phase of sludge treatment (tertiary plants) tended to pump out lower numbers of bacteria (and hence lower numbers of antibiotic resistant bacteria.)

The findings have been published in The ISME Journal. The research is titled “Validated predictive modelling of the environmental resistome.”

Posted by Tim Sandle