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Effect of carbon on whole-biofilm metabolic response to high doses of streptomycin.

Jackson LM, Kroukamp O, Wolfaardt GM - Front Microbiol (2015)

Bottom Line: Biofilms typically exist as complex communities comprising multiple species with the ability to adapt to a variety of harsh conditions.In clinical settings, antibiotic treatments based on planktonic susceptibility tests are often ineffective against biofilm infections.Using a CO2 evolution measurement system we delineated the real-time metabolic response in continuous flow biofilms to streptomycin doses much greater than their planktonic susceptibilities.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Biology, Ryerson University, Toronto ON, Canada.

ABSTRACT
Biofilms typically exist as complex communities comprising multiple species with the ability to adapt to a variety of harsh conditions. In clinical settings, antibiotic treatments based on planktonic susceptibility tests are often ineffective against biofilm infections. Using a CO2 evolution measurement system we delineated the real-time metabolic response in continuous flow biofilms to streptomycin doses much greater than their planktonic susceptibilities. Stable biofilms from a multispecies culture (containing mainly Pseudomonas aeruginosa and Stenotrophomonas maltophilia), Gram-negative environmental isolates, and biofilms formed by pure culture P. aeruginosa strains PAO1 and PAO1 ΔMexXY (minimum planktonic inhibitory concentrations between 1.5 and 3.5 mg/l), were exposed in separate experiments to 4000 mg/l streptomycin for 4 h after which growth medium resumed. In complex medium, early steady state multispecies biofilms were susceptible to streptomycin exposure, inferred by a cessation of CO2 production. However, multispecies biofilms survived high dose exposures when there was extra carbon in the antibiotic medium, or when they were grown in defined citrate medium. The environmental isolates and PAO1 biofilms showed similar metabolic profiles in response to streptomycin; ceasing CO2 production after initial exposure, with CO2 levels dropping toward baseline levels prior to recovery back to steady state levels, while subsequent antibiotic exposure elicited increased CO2 output. Monitoring biofilm metabolic response in real-time allowed exploration of conditions resulting in vulnerability after antibiotic exposure compared to the resistance displayed following subsequent exposures.

No MeSH data available.


Related in: MedlinePlus

Effect of inoculum – the experiments shown in Figure 5 were repeated, with the only exception that the cultures used for inoculation were first streak plated prior to growing overnight cultures. All other information as described in Figure 5.
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Figure 6: Effect of inoculum – the experiments shown in Figure 5 were repeated, with the only exception that the cultures used for inoculation were first streak plated prior to growing overnight cultures. All other information as described in Figure 5.

Mentions: Conversely, when the pure culture PAO1 freezer cultures were streak plated prior to growing overnight cultures for biofilm inoculation, the behavior differed from what is shown in Figures 5A1,A2. When early steady state biofilms of PAO1 originated from streak plates, as old as 2 weeks, they were able to recover from the high dose streptomycin exposure with and without the addition of carbon to the antibiotic medium (Figures 6A1,A2). Unlike PAO1, the PAO1 ΔMexXY strain was unable to recover from high dose streptomycin exposures even when the freezer culture was inoculated onto agar plates prior to growing overnight cultures used for biofilm inoculation (Figures 6B1,B2).


Effect of carbon on whole-biofilm metabolic response to high doses of streptomycin.

Jackson LM, Kroukamp O, Wolfaardt GM - Front Microbiol (2015)

Effect of inoculum – the experiments shown in Figure 5 were repeated, with the only exception that the cultures used for inoculation were first streak plated prior to growing overnight cultures. All other information as described in Figure 5.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4566048&req=5

Figure 6: Effect of inoculum – the experiments shown in Figure 5 were repeated, with the only exception that the cultures used for inoculation were first streak plated prior to growing overnight cultures. All other information as described in Figure 5.
Mentions: Conversely, when the pure culture PAO1 freezer cultures were streak plated prior to growing overnight cultures for biofilm inoculation, the behavior differed from what is shown in Figures 5A1,A2. When early steady state biofilms of PAO1 originated from streak plates, as old as 2 weeks, they were able to recover from the high dose streptomycin exposure with and without the addition of carbon to the antibiotic medium (Figures 6A1,A2). Unlike PAO1, the PAO1 ΔMexXY strain was unable to recover from high dose streptomycin exposures even when the freezer culture was inoculated onto agar plates prior to growing overnight cultures used for biofilm inoculation (Figures 6B1,B2).

Bottom Line: Biofilms typically exist as complex communities comprising multiple species with the ability to adapt to a variety of harsh conditions.In clinical settings, antibiotic treatments based on planktonic susceptibility tests are often ineffective against biofilm infections.Using a CO2 evolution measurement system we delineated the real-time metabolic response in continuous flow biofilms to streptomycin doses much greater than their planktonic susceptibilities.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Biology, Ryerson University, Toronto ON, Canada.

ABSTRACT
Biofilms typically exist as complex communities comprising multiple species with the ability to adapt to a variety of harsh conditions. In clinical settings, antibiotic treatments based on planktonic susceptibility tests are often ineffective against biofilm infections. Using a CO2 evolution measurement system we delineated the real-time metabolic response in continuous flow biofilms to streptomycin doses much greater than their planktonic susceptibilities. Stable biofilms from a multispecies culture (containing mainly Pseudomonas aeruginosa and Stenotrophomonas maltophilia), Gram-negative environmental isolates, and biofilms formed by pure culture P. aeruginosa strains PAO1 and PAO1 ΔMexXY (minimum planktonic inhibitory concentrations between 1.5 and 3.5 mg/l), were exposed in separate experiments to 4000 mg/l streptomycin for 4 h after which growth medium resumed. In complex medium, early steady state multispecies biofilms were susceptible to streptomycin exposure, inferred by a cessation of CO2 production. However, multispecies biofilms survived high dose exposures when there was extra carbon in the antibiotic medium, or when they were grown in defined citrate medium. The environmental isolates and PAO1 biofilms showed similar metabolic profiles in response to streptomycin; ceasing CO2 production after initial exposure, with CO2 levels dropping toward baseline levels prior to recovery back to steady state levels, while subsequent antibiotic exposure elicited increased CO2 output. Monitoring biofilm metabolic response in real-time allowed exploration of conditions resulting in vulnerability after antibiotic exposure compared to the resistance displayed following subsequent exposures.

No MeSH data available.


Related in: MedlinePlus