MRSA Variant Resistant To Last Line of Antibiotic Defense

In the findings of a new study, published by the American Society for Microbiology, it was found that the new resistant MRSA was resistant to vancomycin, the last line of defense for hospital acquired infections. Researchers have found that there have only been twelve confirmed infections of the "super bug" CC5, however if it was to spread in a hospital environment, the consequences could be severe.

MRSA is the leading cause of hospital acquired infections. Vancomycin has been used to treat the more resistant infections as the bacteria has become resistant to other bactericidal drugs. However, the use of vancomycin has resulted in the resistant strain CC5, also known as VRSA. Vancomycin-resistant S. aureus differs to other strains of MRSA in that it is more adept at picking up resistance to antibacterial drugs.

CC5 differs in its approach to surviving the barrage of antibiotics present in hospitals. Whereas MRSA contains an antibiotic protein, VRSA does not, it can co-exist in mixed infections. In place of these bactericidal genes there is a cluster of genes that encode enterotoxins, proteins that attack the host and make conditions more favorable for mixed infections. In addition, CC5 has a mutation in a gene that gives it the ability to assimilate foreign DNA. The resulting conditions increase the possibility of the cross transfer of genes from other bacteria that have resistance to vancomycin. These genes are unique to the CC5 lineage of MRSA.

Researcher Jim Sliwa said "Mixed infections are breeding grounds for antibiotic resistance because they encourage the exchange of genes among very different kinds of organisms. In hospitals, pathogens are under continuous pressure from antibiotics to survive and evolve, and CC5 isolates appear to be very well adapted to succeed by acquiring new resistances. Frequent use of antibiotics in hospital patients could select for strains like CC5 that have an enhanced ability to co-exist with bacteria that provide genes for antibiotic resistance."

A problem caused by modern medicine's over-reliance on antibiotics
The over-use of antibiotics over the years has lead to increases in the number to resistant strains of bacteria. It seems to be the case that the more drugs we throw at these bacteria, the more inventive they become in finding ways to survive. The collective changes in a bacterial organism so that it can co-exist with other bacteria, create an environment that allows it to mix with other bacteria and exchange DNA with them to ensure survival, shows a rapid rate of evolution.

It is clear that a new approach is needed as the current practices are in the process of making bacteria more dangerous. The use of Copper surfaces, on which bacteria can not survive, has been proven to lower infection rates. The use of Silver in solution or in dressings reduces healing times and infection. Cleaner hospitals and effective hand washing by doctors, patients and visitors have also been shown to reduce infection rates.

These measures would reduce the number of infections that required antibiotics, slowing the evolution of the bacteria and allow us time to eradicate these bacteria from our hospitals.