Limits...
High Glucose Concentration Promotes Vancomycin-Enhanced Biofilm Formation of Vancomycin-Non-Susceptible Staphylococcus aureus in Diabetic Mice.

Hsu CY, Shu JC, Lin MH, Chong KY, Chen CC, Wen SM, Hsieh YT, Liao WT - PLoS ONE (2015)

Bottom Line: To address this question, the diabetic mouse model infected by vancomycin-resistant S. aureus (VRSA) was used under vancomycin treatment.A 10- and 1000-fold increase in biofilm-bound bacterial colony forming units was observed in samples from diabetic mice without and with vancomycin treatment, respectively, compared to healthy mice.By contrast, in the absence of glucose vancomycin reduced propensity to form biofilms in vitro through the increased production of proteases and DNases from VRSA.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, No. 259, Wenhua 1st Road, Guishan, Taoyuan 333, Taiwan.

ABSTRACT
We previously demonstrated that vancomycin treatment increased acquisition of eDNA and enhanced biofilm formation of drug-resistant Staphylococcus aureus through a cidA-mediated autolysis mechanism. Recently we found that such enhancement became more significant under a higher glucose concentration in vitro. We propose that besides improper antibiotic treatment, increased glucose concentration environment in diabetic animals may further enhance biofilm formation of drug-resistant S. aureus. To address this question, the diabetic mouse model infected by vancomycin-resistant S. aureus (VRSA) was used under vancomycin treatment. The capacity to form biofilms was evaluated through a catheter-associated biofilm assay. A 10- and 1000-fold increase in biofilm-bound bacterial colony forming units was observed in samples from diabetic mice without and with vancomycin treatment, respectively, compared to healthy mice. By contrast, in the absence of glucose vancomycin reduced propensity to form biofilms in vitro through the increased production of proteases and DNases from VRSA. Our study highlights the potentially important role of increased glucose concentration in enhancing biofilm formation in vancomycin-treated diabetic mice infected by drug-resistant S. aureus.

No MeSH data available.


Related in: MedlinePlus

Vancomycin enhances biofilm formation with glucose but reduces propensity to form biofilms without glucose.(A) A static biofilm assay was performed when VRSA cells (SJC1200) were cultured in BHI medium or medium supplemented with 0.5% (BHIg) or 1.5% (BHIhg) glucose, respectively, in the absence/presence of vancomycin (32 μg/ml). Adherent cells from representative triplicate assays in each condition were stained with safranin O and are shown on the bottom. (B) A time course of the number viable cells was performed when VRSA cells were cultured in BHI or BHIg in the absence (Van0) or presence of vancomycin (32 μg/ml; Van32). The results are presented as the means±sd of the log10 CFU/ml from three separate experiments. (C) A time course of the static biofilm assay was performed when VRSA cells were cultured in different conditions as above. (D) The time course of glucose consumption. (E) A time course of the static biofilm assay was performed as above, but vancomycin was added immediately after the glucose was exhausted in BHI (at 6 h). * P < 0.05 and ** P < 0.005 in this figure and hereafter.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4526670&req=5

pone.0134852.g001: Vancomycin enhances biofilm formation with glucose but reduces propensity to form biofilms without glucose.(A) A static biofilm assay was performed when VRSA cells (SJC1200) were cultured in BHI medium or medium supplemented with 0.5% (BHIg) or 1.5% (BHIhg) glucose, respectively, in the absence/presence of vancomycin (32 μg/ml). Adherent cells from representative triplicate assays in each condition were stained with safranin O and are shown on the bottom. (B) A time course of the number viable cells was performed when VRSA cells were cultured in BHI or BHIg in the absence (Van0) or presence of vancomycin (32 μg/ml; Van32). The results are presented as the means±sd of the log10 CFU/ml from three separate experiments. (C) A time course of the static biofilm assay was performed when VRSA cells were cultured in different conditions as above. (D) The time course of glucose consumption. (E) A time course of the static biofilm assay was performed as above, but vancomycin was added immediately after the glucose was exhausted in BHI (at 6 h). * P < 0.05 and ** P < 0.005 in this figure and hereafter.

Mentions: The static staphylococcal biofilm assay is always performed in BHI medium (containing 0.2% glucose) or other media, in which an additional 0.5% glucose (BHIg) was added [20]. We have previously demonstrated vancomycin-enhanced biofilm formation of the VRSA strain SJC1200 through a bacterial autolysis mechanism when bacteria were cultured in BHIg broth [5]. PIA, composed of the glucose metabolic derivative β-1,6-linked N-acetylglucosamin, is the major biofilm extracellular polymeric substance [23]. We then investigated the effect of the glucose concentration on vancomycin-enhanced biofilm formation. A slight but not significant increase in biofilm materials was observed when bacterial cells were cultured in BHIg and BHIhg compared to BHI broth (Fig 1A). Vancomycin significantly enhanced biofilm formation in BHIg, and the effect was even stronger in BHIhg broth (P < 0.005). Interestingly, biofilm formation was significantly suppressed in BHI broth in the presence of vancomycin (P < 0.005; Fig 1A). Similar results were observed when VISA strain Mu50 was employed under the same conditions (S1 Fig). To rule out the possibility that the difference in the amount of biofilm materials was due to the variation of bacterial viability among different culture conditions, time courses of the number of viable cells (CFU/ml) were performed. Slower bacterial growth was observed in the presence compared to the absence of vancomycin for the first 9 hours, and no significant difference was observed for the duration of the experiment (24 h; Fig 1B).


High Glucose Concentration Promotes Vancomycin-Enhanced Biofilm Formation of Vancomycin-Non-Susceptible Staphylococcus aureus in Diabetic Mice.

Hsu CY, Shu JC, Lin MH, Chong KY, Chen CC, Wen SM, Hsieh YT, Liao WT - PLoS ONE (2015)

Vancomycin enhances biofilm formation with glucose but reduces propensity to form biofilms without glucose.(A) A static biofilm assay was performed when VRSA cells (SJC1200) were cultured in BHI medium or medium supplemented with 0.5% (BHIg) or 1.5% (BHIhg) glucose, respectively, in the absence/presence of vancomycin (32 μg/ml). Adherent cells from representative triplicate assays in each condition were stained with safranin O and are shown on the bottom. (B) A time course of the number viable cells was performed when VRSA cells were cultured in BHI or BHIg in the absence (Van0) or presence of vancomycin (32 μg/ml; Van32). The results are presented as the means±sd of the log10 CFU/ml from three separate experiments. (C) A time course of the static biofilm assay was performed when VRSA cells were cultured in different conditions as above. (D) The time course of glucose consumption. (E) A time course of the static biofilm assay was performed as above, but vancomycin was added immediately after the glucose was exhausted in BHI (at 6 h). * P < 0.05 and ** P < 0.005 in this figure and hereafter.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526670&req=5

pone.0134852.g001: Vancomycin enhances biofilm formation with glucose but reduces propensity to form biofilms without glucose.(A) A static biofilm assay was performed when VRSA cells (SJC1200) were cultured in BHI medium or medium supplemented with 0.5% (BHIg) or 1.5% (BHIhg) glucose, respectively, in the absence/presence of vancomycin (32 μg/ml). Adherent cells from representative triplicate assays in each condition were stained with safranin O and are shown on the bottom. (B) A time course of the number viable cells was performed when VRSA cells were cultured in BHI or BHIg in the absence (Van0) or presence of vancomycin (32 μg/ml; Van32). The results are presented as the means±sd of the log10 CFU/ml from three separate experiments. (C) A time course of the static biofilm assay was performed when VRSA cells were cultured in different conditions as above. (D) The time course of glucose consumption. (E) A time course of the static biofilm assay was performed as above, but vancomycin was added immediately after the glucose was exhausted in BHI (at 6 h). * P < 0.05 and ** P < 0.005 in this figure and hereafter.
Mentions: The static staphylococcal biofilm assay is always performed in BHI medium (containing 0.2% glucose) or other media, in which an additional 0.5% glucose (BHIg) was added [20]. We have previously demonstrated vancomycin-enhanced biofilm formation of the VRSA strain SJC1200 through a bacterial autolysis mechanism when bacteria were cultured in BHIg broth [5]. PIA, composed of the glucose metabolic derivative β-1,6-linked N-acetylglucosamin, is the major biofilm extracellular polymeric substance [23]. We then investigated the effect of the glucose concentration on vancomycin-enhanced biofilm formation. A slight but not significant increase in biofilm materials was observed when bacterial cells were cultured in BHIg and BHIhg compared to BHI broth (Fig 1A). Vancomycin significantly enhanced biofilm formation in BHIg, and the effect was even stronger in BHIhg broth (P < 0.005). Interestingly, biofilm formation was significantly suppressed in BHI broth in the presence of vancomycin (P < 0.005; Fig 1A). Similar results were observed when VISA strain Mu50 was employed under the same conditions (S1 Fig). To rule out the possibility that the difference in the amount of biofilm materials was due to the variation of bacterial viability among different culture conditions, time courses of the number of viable cells (CFU/ml) were performed. Slower bacterial growth was observed in the presence compared to the absence of vancomycin for the first 9 hours, and no significant difference was observed for the duration of the experiment (24 h; Fig 1B).

Bottom Line: To address this question, the diabetic mouse model infected by vancomycin-resistant S. aureus (VRSA) was used under vancomycin treatment.A 10- and 1000-fold increase in biofilm-bound bacterial colony forming units was observed in samples from diabetic mice without and with vancomycin treatment, respectively, compared to healthy mice.By contrast, in the absence of glucose vancomycin reduced propensity to form biofilms in vitro through the increased production of proteases and DNases from VRSA.

View Article: PubMed Central - PubMed

Affiliation: Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, No. 259, Wenhua 1st Road, Guishan, Taoyuan 333, Taiwan.

ABSTRACT
We previously demonstrated that vancomycin treatment increased acquisition of eDNA and enhanced biofilm formation of drug-resistant Staphylococcus aureus through a cidA-mediated autolysis mechanism. Recently we found that such enhancement became more significant under a higher glucose concentration in vitro. We propose that besides improper antibiotic treatment, increased glucose concentration environment in diabetic animals may further enhance biofilm formation of drug-resistant S. aureus. To address this question, the diabetic mouse model infected by vancomycin-resistant S. aureus (VRSA) was used under vancomycin treatment. The capacity to form biofilms was evaluated through a catheter-associated biofilm assay. A 10- and 1000-fold increase in biofilm-bound bacterial colony forming units was observed in samples from diabetic mice without and with vancomycin treatment, respectively, compared to healthy mice. By contrast, in the absence of glucose vancomycin reduced propensity to form biofilms in vitro through the increased production of proteases and DNases from VRSA. Our study highlights the potentially important role of increased glucose concentration in enhancing biofilm formation in vancomycin-treated diabetic mice infected by drug-resistant S. aureus.

No MeSH data available.


Related in: MedlinePlus