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Effects of Carbon Dioxide Aerosols on the Viability of Escherichia coli during Biofilm Dispersal.

Singh R, Monnappa AK, Hong S, Mitchell RJ, Jang J - Sci Rep (2015)

Bottom Line: A periodic jet of carbon dioxide (CO2) aerosols is a very quick and effective mechanical technique to remove biofilms from various substrate surfaces.Indirect proof that the aerosols are damaging the bacteria was found using a recombinant E. coli expressing the cyan fluorescent protein, as nearly half of the fluorescence was found in the supernatant after CO2 aerosol treatment, while the rest was associated with the bacterial pellet.In comparison, the supernatant fluorescence was only 9% when the enzymes were used to disperse the biofilm.

View Article: PubMed Central - PubMed

Affiliation: School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, S. Korea.

ABSTRACT
A periodic jet of carbon dioxide (CO2) aerosols is a very quick and effective mechanical technique to remove biofilms from various substrate surfaces. However, the impact of the aerosols on the viability of bacteria during treatment has never been evaluated. In this study, the effects of high-speed CO2 aerosols, a mixture of solid and gaseous CO2, on bacteria viability was studied. It was found that when CO2 aerosols were used to disperse biofilms of Escherichia coli, they led to a significant loss of viability, with approximately 50% of the dispersed bacteria killed in the process. By comparison, 75.6% of the biofilm-associated bacteria were viable when gently dispersed using Proteinase K and DNase I. Indirect proof that the aerosols are damaging the bacteria was found using a recombinant E. coli expressing the cyan fluorescent protein, as nearly half of the fluorescence was found in the supernatant after CO2 aerosol treatment, while the rest was associated with the bacterial pellet. In comparison, the supernatant fluorescence was only 9% when the enzymes were used to disperse the biofilm. As such, these CO2 aerosols not only remove biofilm-associated bacteria effectively but also significantly impact their viability by disrupting membrane integrity.

No MeSH data available.


Related in: MedlinePlus

Confocal microscopic image of one-day grown E. coli biofilms stained with the BacLight stain (SYTO-9 and propidium iodide) after their respective treatments.(a) Untreated control biofilm. (b) HEPES soaked biofilm. (c) E. coli biofilm after treatment with Proteinase K and DNase I. (d) E. coli biofilm treated with CO2 aerosols. The scale bars are 50 μm.
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f2: Confocal microscopic image of one-day grown E. coli biofilms stained with the BacLight stain (SYTO-9 and propidium iodide) after their respective treatments.(a) Untreated control biofilm. (b) HEPES soaked biofilm. (c) E. coli biofilm after treatment with Proteinase K and DNase I. (d) E. coli biofilm treated with CO2 aerosols. The scale bars are 50 μm.

Mentions: To analyze these results deeper, particularly with regards to biofilm viability, we stained the biofilms with a BacLight stain (Invitrogen, USA) containing both SYTO9 and propidium iodide (PI), which labels the live cells green and the dead cells red, respectively. Figure 2a shows the fluorescent image of the untreated E. coli biofilm. Although not quantitative, the greater prevalence of green fluorescence suggests that the majority of the culture was viable, a finding that also appears true of the HEPES-treated biofilm (Fig. 2b). Treatment of the biofilm with either hydrolytic enzymes (Fig. 2c) or the aerosols (Fig. 2d), however, led to a significant decrease in both fluorescent signals, affirming the findings of Fig. 1 where a significant number of the bacteria cells were removed by both of these treatments.


Effects of Carbon Dioxide Aerosols on the Viability of Escherichia coli during Biofilm Dispersal.

Singh R, Monnappa AK, Hong S, Mitchell RJ, Jang J - Sci Rep (2015)

Confocal microscopic image of one-day grown E. coli biofilms stained with the BacLight stain (SYTO-9 and propidium iodide) after their respective treatments.(a) Untreated control biofilm. (b) HEPES soaked biofilm. (c) E. coli biofilm after treatment with Proteinase K and DNase I. (d) E. coli biofilm treated with CO2 aerosols. The scale bars are 50 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561891&req=5

f2: Confocal microscopic image of one-day grown E. coli biofilms stained with the BacLight stain (SYTO-9 and propidium iodide) after their respective treatments.(a) Untreated control biofilm. (b) HEPES soaked biofilm. (c) E. coli biofilm after treatment with Proteinase K and DNase I. (d) E. coli biofilm treated with CO2 aerosols. The scale bars are 50 μm.
Mentions: To analyze these results deeper, particularly with regards to biofilm viability, we stained the biofilms with a BacLight stain (Invitrogen, USA) containing both SYTO9 and propidium iodide (PI), which labels the live cells green and the dead cells red, respectively. Figure 2a shows the fluorescent image of the untreated E. coli biofilm. Although not quantitative, the greater prevalence of green fluorescence suggests that the majority of the culture was viable, a finding that also appears true of the HEPES-treated biofilm (Fig. 2b). Treatment of the biofilm with either hydrolytic enzymes (Fig. 2c) or the aerosols (Fig. 2d), however, led to a significant decrease in both fluorescent signals, affirming the findings of Fig. 1 where a significant number of the bacteria cells were removed by both of these treatments.

Bottom Line: A periodic jet of carbon dioxide (CO2) aerosols is a very quick and effective mechanical technique to remove biofilms from various substrate surfaces.Indirect proof that the aerosols are damaging the bacteria was found using a recombinant E. coli expressing the cyan fluorescent protein, as nearly half of the fluorescence was found in the supernatant after CO2 aerosol treatment, while the rest was associated with the bacterial pellet.In comparison, the supernatant fluorescence was only 9% when the enzymes were used to disperse the biofilm.

View Article: PubMed Central - PubMed

Affiliation: School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, S. Korea.

ABSTRACT
A periodic jet of carbon dioxide (CO2) aerosols is a very quick and effective mechanical technique to remove biofilms from various substrate surfaces. However, the impact of the aerosols on the viability of bacteria during treatment has never been evaluated. In this study, the effects of high-speed CO2 aerosols, a mixture of solid and gaseous CO2, on bacteria viability was studied. It was found that when CO2 aerosols were used to disperse biofilms of Escherichia coli, they led to a significant loss of viability, with approximately 50% of the dispersed bacteria killed in the process. By comparison, 75.6% of the biofilm-associated bacteria were viable when gently dispersed using Proteinase K and DNase I. Indirect proof that the aerosols are damaging the bacteria was found using a recombinant E. coli expressing the cyan fluorescent protein, as nearly half of the fluorescence was found in the supernatant after CO2 aerosol treatment, while the rest was associated with the bacterial pellet. In comparison, the supernatant fluorescence was only 9% when the enzymes were used to disperse the biofilm. As such, these CO2 aerosols not only remove biofilm-associated bacteria effectively but also significantly impact their viability by disrupting membrane integrity.

No MeSH data available.


Related in: MedlinePlus