London, Mar 12: It's bacteria breakthrough! British scientists claim to have discovered how a bacterium which causes pneumonia has become resistant to penicillin.

Penicillin, a popular anti-biotic, acts by preventing the construction of an essential component of the bacterial cell wall called the peptidoglycan. This component provides a protective mesh around the otherwise fragile bacterial cell.

The researchers at the University of Warwick focused on a protein called MurM which has been linked to changes in the chemical make-up of the peptidoglycan observed in patients infected with penicillin-resistant Streptococcus pneumoniae that kills over five million children a year worldwide.

They found that the protein acted as an enzyme, playing a key role in the formation of structures within the peptidoglycan. The higher the levels of MurM activity, the stronger the peptidoglycan became and the more likely the bacterium would be drug resistant as a result.

The researchers were able to replicate the activity of MurM in a test tube, which allowed them to study in close detail exactly how it is deployed by Streptococcus pneumoniae to neutralise penicillin -- the results of the study have been published in the 'Journal of Biological Chemistry'.

The University of Warwick team hopes that they will soon be able to restore penicillin's full anti-biotic effect, thereby facilitating the development of new drugs in two to three years' time.

"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," the 'BBC News' portal quoted lead researcher Dr Adrian Lloyd as saying.