Polyoxotungstates reduce the beta-lactam resistance of methicillin-resistant Staphylococcus aureus

Bacterial strains isolated from clinical specimens have become more and more resistant to many anti-microbials. This is because we have consumed large amounts of strong antimicrobials over long periods of time and thus bacterial cells are able to survive by altering the target(s) of antimicrobial agents. A good example of this phenomenon is methicillin-resistant Staphylococcus aureus (MRSA). One of the cell wall-synthesizing enzymes (known as PBP2') of this pathogen has low affinity to beta-lactams, and therefore the bacterial cells continue to grow even under high concentrations of the agents. However, this drug resistance does not seem to be total. They seem to have some weak spots and several substances are known to sensitize strains of MRSA to beta-lactams. This review discusses the ability of polyoxotungstates (POTs) to sensitize MRSA to beta-lactams by reducing the expression of PBP2'. It is also possible that the sensitization is a type of stress response of MRSA to POTs. This idea may provide a hint for the development of a new antimicrobial agent.