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

Abstract

In a previous study, it was found that polyoxotungstates such as undecatungstosilicate (SiW11) greatly sensitized strains of methicillin-resistant Staphylococcus aureus (MRSA) to ␤-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 ␤-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'.

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

“…It is noteworthy that the geometric pattern of the colonies was roughly related to the result of the population analysis [137]. When POTs and β-lactams are used in an appropriate combination, we may estimate the mechanism of resistance working in an MRSA strain, which could possibly lead to the use of POTs as a "tool" in laboratory tests in clinical microbiology, as suggested elsewhere [59].…”

“…However, POTs did not strongly suppress the bacterial growth (measured by optical density of the culture medium) [49,50]. appears to be weak, since this cephem had previously acted on MRSA prior to being sensitized by POTs [59].…”

Tungsten accumulates in the intervertebral disc and vertebrae stimulating disc degeneration and upregulating markers of inflammation and pain

“…Tungsten concentrations in the urine of several veterans were significantly higher (11.6 %) than the upper reference limit established in the National Health and Nutrition Examination Survey NHANES Database (0.003-2.70 μg/g creatinine) (Gaitens et al, 2017). In addition to occupational exposure, increased concentration of tungsten has been observed in blood and urine from patients with tungsten-based medical therapies (Domingo, 2002;Lalak and Moussa, 2002;Tajima, 2001;Tajima, 2003). For instance, tungsten coils used in peripheral vascular embolisation procedures have been reported to corrode and degrade over time increasing urinary tungsten concentration in patients with these implants (Bachthaler et al, 2004;Barrett et al, 2000;Bolt and Mann, 2016;Lalak and Moussa, 2002).…”

11-Tungstophosphate with Iron(II) and Hydrogen Peroxide Efficiently Detached Bacterial Biofilm

“…16) f) Unbuffered during the reaction to avoid the formation of PW 11 . 43,44) After the reaction, 2.5 M phosphate buffer was added to the reaction mixture at a ratio of 1 : 50 to make the final concentration 50 mM (other preparation was buffered with 50 mM phosphate beforehand). g) Fluorescence intensity was gradually increased in the absence of H 2 O 2 (autoxidation rates were [PW 11 ϩFe Franklin Lakes, NJ, U.S.A.).…”