How superbug makes targeted drugs impotent

Last Updated: Mon, Sep 02, 2013 07:52 hrs

Researchers have identified a novel mechanism that a particular superbug uses to fight off a key front-line antibiotic called daptomycin.

Cesar Arias, M.D., Ph.D., the study's senior author and associate professor in the Division of Infectious Diseases at the University of Texas Health Science Center at Houston (UTHealth) Medical School, said that antibiotic resistance is one of the major public health threats of the 21st Century.

The study focused on a hard-to-treat superbug called vancomycin-resistant enterococci or VRE, which usually affect patients who have a compromised immune system or who are critically ill.

The superbug appears to be building resistance to one of the few antibiotics that works against it - daptomycin.

To see how VRE developed the ability to ward off daptomycin during the course of treatment, Arias' team used fluorescent labeled daptomycin and observed the interaction between the superbug and the antibiotic with the aid of advanced microscopy techniques.

Contrary to the prevailing belief that tiny electrical charges on the surface of VRE cells repel the antibiotic, the researchers report that the VRE cells actually divert the antibiotic and "trap" it to an area where it is rendered ineffective.

The mechanism of resistance is completed by changing the composition of the bacterial cell membrane. The study also provides the genetic and biochemical basis for the resistance pathway. (ANI)

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