Related Experiment Video
Updated: Sep 26, 2026

Stress-induced Antibiotic Susceptibility Testing on a Chip
Published on: January 8, 2014
Effects of tungstosilicate on strains of methicillin-resistant Staphylococcus aureus with unique resistant mechanisms
1Clinical Laboratory, Saga Medical School Hospital, Nabeshima, Saga, Saga 849-8501, Japan. tajima@post.saga-med.ac.jp
Abstract:
In a previous study, it was found that polyoxotungstates such as undecatungstosilicate (SiW11) greatly sensitized strains of methicillin-resistant Staphylococcus aureus (MRSA) to beta-lactams. In this report, the effects of SiW11 on several MRSA strains with unique resistant mechanisms were studied. SiW11 was still effective to MRSA mutants with higher beta-lactam resistance due to reduced cell-lytic activity. Since the antimicrobial effect of TOC-39 (a cephem antibiotic with strong affinity to penicillin-binding protein (PBP) 2') was not strongly enhanced in any case, it was confirmed that the sensitizing effect of SiW11 is due to reduced expression of PBP2'. However, the sensitizing effect of SiW11 was relatively weak in MRSA strains with lowered susceptibility to glycopeptide antibiotics. A certain resistant mechanism other than the mecA-PBP2' system worked in such a strain. Interestingly, an MRSA mutant with the Eagle-type resistance was dramatically sensitized. This result suggests that SiW11 has another site of action besides reducing the expression of PBP2'.
Related Concept Videos
Mechanism of Antibiotic Resistance in MRSA
Clinical Significance of Antibiotic Resistance
Staphylococcal Skin Infections
Development of Antibiotic Resistance
Inhibitors of Bacterial Protein Synthesis