March 12, 2008

New Hope For Penicillin

Scientists in Britain have discovered how a pneumonia-causing bacterium becomes resistant to antibiotics.

University of Warwick researchers hope the findings could pave the way to restoring the full effects of antibiotics such as penicillin, and perhaps lead to the creation of new drugs to treat infections such as MRSA.

The research focused on the Streptococcus pneumoniae bacterium, which kills 5m children a year worldwide.   It has been one of a growing number of bacteria that have become resistant to penicillin in recent times, according to BBC News reports.

Penicillin, discovered in 1928 by Sir Alexander Fleming, became the first widely used antibiotic during the 1940s.  It acts by preventing the construction of a key component of the bacterial cell wall called the Peptidoglycan, which provides a protective mesh around the fragile bacteria.

The researchers focused on a protein named MurM that is associated with changes in the chemical make-up of the peptidoglycan seen in patients infected with penicillin-resistant Streptococcus pneumoniae.

The team found that this protein acted as an enzyme that helped the peptidoglycan build up its strength.  The higher the levels of MurM, the stronger the peptidoglycan became, and the more likely the bacterium would become drug resistant.

The researchers replicated the activity of MurM in a test tube, allowing them to examine in close detail the way it is deployed by Streptococcus pneumoniae to neutralize penicillin.

The team believes their study could someday result in better treatments that block bacterial resistance by disrupting the chemistry of MurM.  These treatments could be for Streptococcus pneumoniae, but also other for bacteria such as MRSA, which also appears to rely on the same chemistry to build resistance.

Dr Adrian Lloyd, the study's lead researcher, said it was possible that new drugs could be developed in two to three years.

"Because we now know in detail what this protein needs to be able to do its job and promote bacterial resistance we should be able to develop drugs to stop it from doing so," he told BBC News.

Professor Kevin Kerr, a consultant microbiologist at Harrogate District Hospital, told BBC News the findings were interesting, but much more work was needed.

"Solving the problem of penicillin resistance in pneumococci is a key priority for modern medicine and these results provide an important piece in the puzzle.

"The challenge must now be to see if this discovery can be exploited through the identification and development of new drugs which can inhibit this enzyme," he said.

On the Net:

University of Warwick

UK Bacterial Cell Wall Biosynthesis Network or UK-BaCWAN

The study was published in the journal of Biological Chemistry.  A summary of the report can be viewed here.