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Development of benzo[1,4]oxazines as biofilm inhibitors and dispersal agents against Vibrio cholerae.

Warner CJ, Cheng AT, Yildiz FH, Linington RG - Chem. Commun. (Camb.) (2015)

Bottom Line: Bacterial biofilms are estimated to be associated with over 65 percent of all nosocomial infections.However, no therapeutics have been approved by the FDA which directly mediate biofilm formation or persistence.Herein we report oxazine as a highly potent inhibitor, disperser and in the presence of the appropriate antibiotic eradicator of V. cholerae biofilms.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Biochemistry, University of California Santa Cruz, California, 95064, USA. rliningt@ucsc.edu.

ABSTRACT
Bacterial biofilms are estimated to be associated with over 65 percent of all nosocomial infections. However, no therapeutics have been approved by the FDA which directly mediate biofilm formation or persistence. Herein we report oxazine as a highly potent inhibitor, disperser and in the presence of the appropriate antibiotic eradicator of V. cholerae biofilms.

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Related in: MedlinePlus

Static well images of V. cholerae biofilms. Static well GFP images of V. cholerae biofilms and normalized OD600 readings. In all instances the antibiotic, dispersal agent or a combination of the two were introduced after two hours of incubation and incubated for a further 4 hours before being washed and analyzed. (A) DMSO control; (B) 50 μM ciprofloxacin; (C) 50 μM erythromycin; (D) 20 μM compound 25; (E) 20 μM compound 25 and 50 μM ciprofloxacin; (F) 20 μM compound 25 and 50 μM erythromycin. White bars represent 50 μm.
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fig2: Static well images of V. cholerae biofilms. Static well GFP images of V. cholerae biofilms and normalized OD600 readings. In all instances the antibiotic, dispersal agent or a combination of the two were introduced after two hours of incubation and incubated for a further 4 hours before being washed and analyzed. (A) DMSO control; (B) 50 μM ciprofloxacin; (C) 50 μM erythromycin; (D) 20 μM compound 25; (E) 20 μM compound 25 and 50 μM ciprofloxacin; (F) 20 μM compound 25 and 50 μM erythromycin. White bars represent 50 μm.

Mentions: A major challenge surrounding the treatment of biofilm-mediated infections is that bacterial cells within the biofilm have the potential to enter a latent state that renders them much less susceptible to traditional antibiotics.4 One potential application for biofilm dispersal agents is as combination therapies with existing antibiotics to both clear and eliminate otherwise persistent infections. To examine whether our biofilm dispersal model could recapitulate this antibiotic resistance for V. cholerae we screened five FDA-approved antibiotics (ciprofloxacin, erythromycin, azithromycin, doxycycline and furazilidinone) in the dispersal assay. Interestingly, without the presence of compound 25, erythromycin, ciprofloxacin and furazilidinone (all therapeutics prescribed as first stage treatments for V. cholerae infection) failed to induce biofilm dispersal, with confocal microscopy indicating the presence of large biofilm macrocolonies and very few background planktonic cells. Optical density readings confirmed this observation and suggested that these antibiotics have the capacity to eradicate cells in the planktonic state, but not significantly impact biofilm coverage. By contrast, addition of 20 μM of compound 25 in addition to 50 μM of either erythromycin or ciprofloxacin resulted in near quantitative elimination of biofilm coverage, and a lowering in the cellular viability, as determined by OD600 analysis, indicating that these drug combinations possess the ability to both clear and kill established V. cholerae infections (Fig. 2). One limitation of image-based high content screening is that samples must be incubated under static culture conditions. The disadvantage of this method is that static culture allows the accumulation of signaling factors and quorum sensing molecules including V. cholerae autoinducer-1 (CAI-1), autoinducer-2 (AI-2) and indole which all impact the rate and degree of biofilm formation.15,16


Development of benzo[1,4]oxazines as biofilm inhibitors and dispersal agents against Vibrio cholerae.

Warner CJ, Cheng AT, Yildiz FH, Linington RG - Chem. Commun. (Camb.) (2015)

Static well images of V. cholerae biofilms. Static well GFP images of V. cholerae biofilms and normalized OD600 readings. In all instances the antibiotic, dispersal agent or a combination of the two were introduced after two hours of incubation and incubated for a further 4 hours before being washed and analyzed. (A) DMSO control; (B) 50 μM ciprofloxacin; (C) 50 μM erythromycin; (D) 20 μM compound 25; (E) 20 μM compound 25 and 50 μM ciprofloxacin; (F) 20 μM compound 25 and 50 μM erythromycin. White bars represent 50 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4288701&req=5

fig2: Static well images of V. cholerae biofilms. Static well GFP images of V. cholerae biofilms and normalized OD600 readings. In all instances the antibiotic, dispersal agent or a combination of the two were introduced after two hours of incubation and incubated for a further 4 hours before being washed and analyzed. (A) DMSO control; (B) 50 μM ciprofloxacin; (C) 50 μM erythromycin; (D) 20 μM compound 25; (E) 20 μM compound 25 and 50 μM ciprofloxacin; (F) 20 μM compound 25 and 50 μM erythromycin. White bars represent 50 μm.
Mentions: A major challenge surrounding the treatment of biofilm-mediated infections is that bacterial cells within the biofilm have the potential to enter a latent state that renders them much less susceptible to traditional antibiotics.4 One potential application for biofilm dispersal agents is as combination therapies with existing antibiotics to both clear and eliminate otherwise persistent infections. To examine whether our biofilm dispersal model could recapitulate this antibiotic resistance for V. cholerae we screened five FDA-approved antibiotics (ciprofloxacin, erythromycin, azithromycin, doxycycline and furazilidinone) in the dispersal assay. Interestingly, without the presence of compound 25, erythromycin, ciprofloxacin and furazilidinone (all therapeutics prescribed as first stage treatments for V. cholerae infection) failed to induce biofilm dispersal, with confocal microscopy indicating the presence of large biofilm macrocolonies and very few background planktonic cells. Optical density readings confirmed this observation and suggested that these antibiotics have the capacity to eradicate cells in the planktonic state, but not significantly impact biofilm coverage. By contrast, addition of 20 μM of compound 25 in addition to 50 μM of either erythromycin or ciprofloxacin resulted in near quantitative elimination of biofilm coverage, and a lowering in the cellular viability, as determined by OD600 analysis, indicating that these drug combinations possess the ability to both clear and kill established V. cholerae infections (Fig. 2). One limitation of image-based high content screening is that samples must be incubated under static culture conditions. The disadvantage of this method is that static culture allows the accumulation of signaling factors and quorum sensing molecules including V. cholerae autoinducer-1 (CAI-1), autoinducer-2 (AI-2) and indole which all impact the rate and degree of biofilm formation.15,16

Bottom Line: Bacterial biofilms are estimated to be associated with over 65 percent of all nosocomial infections.However, no therapeutics have been approved by the FDA which directly mediate biofilm formation or persistence.Herein we report oxazine as a highly potent inhibitor, disperser and in the presence of the appropriate antibiotic eradicator of V. cholerae biofilms.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Biochemistry, University of California Santa Cruz, California, 95064, USA. rliningt@ucsc.edu.

ABSTRACT
Bacterial biofilms are estimated to be associated with over 65 percent of all nosocomial infections. However, no therapeutics have been approved by the FDA which directly mediate biofilm formation or persistence. Herein we report oxazine as a highly potent inhibitor, disperser and in the presence of the appropriate antibiotic eradicator of V. cholerae biofilms.

Show MeSH
Related in: MedlinePlus