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Safety, efficacy and utility of methods of transferring adhesive and cohesive Escherichia coli cells to microplates to avoid aerosols.

Ericksen B - F1000Res (2014)

Bottom Line: The virtual colony count (VCC) microbiological assay has been utilized for over a decade to measure the antimicrobial activity of peptides such as defensins and LL-37 against biosafety level (BSL)-1 and BSL-2 bacteria including Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Enterobacter aerogenes.  In addition, a modified pipetting technique was presented in a 2011 study of defensin activity against the BSL-3 pathogen Bacillus anthracis.  Both studies were published in the journal Antimicrobial Agents and Chemotherapy.  Here I report that the method can also detect cross-contamination caused by aerosols utilizing the VCC method of data analysis by quantitative growth kinetics (QGK).  The QGK threshold time, or T t, equivalent to the cycle time C t reported in 1996 by Heid et al., precisely identifies when wells were inoculated.

View Article: PubMed Central - PubMed

Affiliation: University of Maryland School of Medicine, Institute of Human Virology, 725 W. Lombard St., Baltimore, MD, USA.

ABSTRACT
The virtual colony count (VCC) microbiological assay has been utilized for over a decade to measure the antimicrobial activity of peptides such as defensins and LL-37 against biosafety level (BSL)-1 and BSL-2 bacteria including Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Enterobacter aerogenes.  In addition, a modified pipetting technique was presented in a 2011 study of defensin activity against the BSL-3 pathogen Bacillus anthracis.  Both studies were published in the journal Antimicrobial Agents and Chemotherapy.  Here I report that the method can also detect cross-contamination caused by aerosols utilizing the VCC method of data analysis by quantitative growth kinetics (QGK).  The QGK threshold time, or T t, equivalent to the cycle time C t reported in 1996 by Heid et al., precisely identifies when wells were inoculated.

No MeSH data available.


Related in: MedlinePlus

96-well plate configurations.PanelsB andC depict contamination control wells on the right edge (columns 11–12) so that the eight-channel pipettor passes over them if when used by a right-handed operator. These wells could be moved to the left edge if the operator is left-handed.
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f1: 96-well plate configurations.PanelsB andC depict contamination control wells on the right edge (columns 11–12) so that the eight-channel pipettor passes over them if when used by a right-handed operator. These wells could be moved to the left edge if the operator is left-handed.

Mentions: The VCC plate configuration as initially published in 2005 (Figure 1A) used the 36 wells around the edge of the 96-well plate (rows A and H and columns 1 and 12) as contamination control wells. Turbidity in these wells could have been the result of either environmental contamination or cross-contamination, but sampling wells over the course of many experiments revealed colony morphologies that were almost invariably consistent with the bacterial strain studied that day. Six alternating VCC experiments usingEscherichia coli ATCC 25922 andStaphylococcus aureus confirmed this conclusion by producing colonies only consistent with the strain studied that day, not the strain studied in the previous experiment or an environmental isolate with a colony morphology matching neither strain.


Safety, efficacy and utility of methods of transferring adhesive and cohesive Escherichia coli cells to microplates to avoid aerosols.

Ericksen B - F1000Res (2014)

96-well plate configurations.PanelsB andC depict contamination control wells on the right edge (columns 11–12) so that the eight-channel pipettor passes over them if when used by a right-handed operator. These wells could be moved to the left edge if the operator is left-handed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4309163&req=5

f1: 96-well plate configurations.PanelsB andC depict contamination control wells on the right edge (columns 11–12) so that the eight-channel pipettor passes over them if when used by a right-handed operator. These wells could be moved to the left edge if the operator is left-handed.
Mentions: The VCC plate configuration as initially published in 2005 (Figure 1A) used the 36 wells around the edge of the 96-well plate (rows A and H and columns 1 and 12) as contamination control wells. Turbidity in these wells could have been the result of either environmental contamination or cross-contamination, but sampling wells over the course of many experiments revealed colony morphologies that were almost invariably consistent with the bacterial strain studied that day. Six alternating VCC experiments usingEscherichia coli ATCC 25922 andStaphylococcus aureus confirmed this conclusion by producing colonies only consistent with the strain studied that day, not the strain studied in the previous experiment or an environmental isolate with a colony morphology matching neither strain.

Bottom Line: The virtual colony count (VCC) microbiological assay has been utilized for over a decade to measure the antimicrobial activity of peptides such as defensins and LL-37 against biosafety level (BSL)-1 and BSL-2 bacteria including Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Enterobacter aerogenes.  In addition, a modified pipetting technique was presented in a 2011 study of defensin activity against the BSL-3 pathogen Bacillus anthracis.  Both studies were published in the journal Antimicrobial Agents and Chemotherapy.  Here I report that the method can also detect cross-contamination caused by aerosols utilizing the VCC method of data analysis by quantitative growth kinetics (QGK).  The QGK threshold time, or T t, equivalent to the cycle time C t reported in 1996 by Heid et al., precisely identifies when wells were inoculated.

View Article: PubMed Central - PubMed

Affiliation: University of Maryland School of Medicine, Institute of Human Virology, 725 W. Lombard St., Baltimore, MD, USA.

ABSTRACT
The virtual colony count (VCC) microbiological assay has been utilized for over a decade to measure the antimicrobial activity of peptides such as defensins and LL-37 against biosafety level (BSL)-1 and BSL-2 bacteria including Escherichia coli, Staphylococcus aureus, Bacillus cereus, and Enterobacter aerogenes.  In addition, a modified pipetting technique was presented in a 2011 study of defensin activity against the BSL-3 pathogen Bacillus anthracis.  Both studies were published in the journal Antimicrobial Agents and Chemotherapy.  Here I report that the method can also detect cross-contamination caused by aerosols utilizing the VCC method of data analysis by quantitative growth kinetics (QGK).  The QGK threshold time, or T t, equivalent to the cycle time C t reported in 1996 by Heid et al., precisely identifies when wells were inoculated.

No MeSH data available.


Related in: MedlinePlus