Tuesday, June 11, 2013

FAQ: How do bacteria become resistant to antibiotics?

Scientist continue to struggle to answer the question of how bacteria obtain antibiotic resistance. However, a recent paper published in Nature entitled: 'Antibiotic treatment expands the resistance reservoir and ecological network of the phage metagenome' suggests that bacteriophages may be involved.

Transmission electron micrograph of the bacteriophage Qβ
attached to sex pilus of the bacterium Escherichia coli

 by Dr Graham Beards
Bacteriophages, or simply phages, are viruses that infect bacteria. Phages are known for their capacity to move genes from one bacteria to another. With this in mind, the scientists from Boston University and Harvard, decided to focus on the effect of drug treatment on phages rather than bacteria. They gave mice one of two commonly prescribed antibiotics and subsequently harvested viruses from the fecal matter after 8 weeks. They then identified the viral genes present by comparing them to a database of known genes.

The results showed that phages from antibiotic treated animals did indeed carry a higher number of genes for drug-resistance. Furthermore, they were able to transfer the resistance genes to bacteria. When phages isolated from antibiotic treated mice were combined with bacteria from untreated mice the researchers saw an increase in antibiotic resistance that was 2 to 3 times what is normally seen.

These results open the door for new avenues of treatment that target the phage rather than the bacteria. Assessing viral susceptibility to drug treatment is a potential application that could employ the NEPHELOstar Plus from BMG LABTECH. Since a nephelometer detects insoluble particles with high sensitivity using a laser, the NEPHELOstar Plus has the potential to be able to monitor changes in the amount of virus in a sample and to do so in a microplate format.

For more information on the NEPHELOstar Plus and other microplate readers from BMG LABTECH please visit our website: www.bmglabtech.com