Anionic properties of β-lactam-enhancing factor on methicillin-resistant Staphylococcus aureus

Lacunary-Substituted Undecatungstosilicates Sensitize Methicillin-Resistant Staphylococcus aureus to .BETA.-Lactams.

“…Nucleic acids can be regarded as a type of polyanion, and the polyoxotungstates probably inhibited the enzymes by acting as a nucleic acid-analogue in a charge interaction. 3,[22][23][24] Other enzymes (such as transaminases and proteases) were generally insensitive to these tungsten compounds.…”

Polyoxotungstates Reduce the β-Lactam Resistance of Methicillin-Resistant Staphylococcus aureus

“…The sensitizing effects of POTs can be easily observed using the paper disk method. The experimental details are described in our previous reports [42][43][44][45][46][47][48][49].…”

“…For instance, "+7" means that a compound made the strain (2 7 =)128-fold susceptible to MPIPC. The established bacterial strains used in the experiments are described in our reports (NCTC8325/ATCC29213 = MSSA, ATCC33591/ATCC43300/MRS394-1 = MRSA) [42][43][44][45][46][47][48][49]. c Means of two independent triplicate determinations (n = 6) are shown here.…”

“…3) were also found entirely by chance [42][43][44]. Briefly, a mixture of tungstate (WO 4 2-) and phosphate (HPO 4 2-), which was prepared for another purpose and left sitting for a long period, was spilled by accident on an agar plate, wherein antimicrobial susceptibility of an MRSA strain was being measured by the paper disk method.…”

Effects of Tungstosilicate on Strains of Methicillin‐Resistant Staphylococcus aureus with Unique Resistant Mechanisms

“…Although these POTs alone did not show significant antibacterial activity, they reduced minimum inhibitory concentrations (MICs) of almost all the β-lactams such as methicillin (dimethoxyphenylpenicillin, DMPPC) and oxacillin (methylphenylisoxazolylpenicillin, MPIPC) to 1/10-1/1,000, whereas constituents of the POTs (e.g., WO 4 2Ϫ , HPO 4 2Ϫ , SiO 3 2Ϫ ) had no effect (3,(19)(20)(21)(22)(23)(24)26).…”