FREQUENTLY ASKED QUESTIONS

CAN THE BACTIQUANT-SURFACE METHOD BE USED FOR GENERAL HYGIENE ASSESSMENT?

No, not in its current form. The sensitivity of Bactiquant-surface method has been targeted so as to fit criteria that meet the needs of the flooding and sewage backflow remediation industry. Here the clean criteria has been targeted to distinguish between visually clean and visually dirty surfaces in normal buildings. A visually clean surface in a non problem building is not necessarily as clean as would be needed in e.g. a hospital operation room.

CAN THE BACTIQUANT-SURFACE HELP IN MAKING THE REMEDIATION PROCESS MORE EFFICIENT AND ECONOMIC?

Yes. Not having to wait for lab results allows for rapid demobilization of remediation barriers and containment systems,and  enables the re-occupancy of an area that much faster. Additionally, the Bactiquant-surface method can be used to evaluate the efficacy of different methods for cleaning contaminated materials. A test cleaning assessment using the Bactiquant-surface method enables remediators and consultants to quickly, and empirically, identify materials that can and cannot be cleaned.

CAN BACTIQUANT-SURFACE REPLACE MEASUREMENTS OF E. COLI ON A REMEDIATION SITE?

Traditionally, assessment after flooding events has been performed using cultivation of coliform and fecal indicator bacteria like E. coli. Assessments have focused on the risk of infection as the main health concern. This approach is inadequate due to  the fact that E. coli and many pathogenic bacteria typically have a very short survival time in the environment. Even with no measurable E.coli,  infectious bacteria with longer survival times can still be present. Further, large reservoirs of non infectious bacterial can remain undetected. Health effects of bacterial contamination are not solely a question of risk of infection from pathogenic bacteria. A high number of bacteria in general can cause other health effects such as hypersensitivity pneumonitis, allergy, and inflammation due to the influence of bacterial cell wall agents. A high level of any type bacteria left on surfaces has the potential to affect human health and that is true even though they are dead. The Bactiquant-surface method gives a measure of the total level of bacteria on a surface.

IS THE BACTIQUANT-SURFACE METHOD MORE FAIR TO THE CONTRACTOR?

If you define "fair" as confirming or verifying that the contractor has accomplished the task of returning materials to a like-new condition, then the Bactiquant-surface is extremely fair. However, it can be argued that the Bactiquant-surface is a rigorous, unambiguous test that may be more difficult for some less than thorough contractors to pass than culture plate testing or visual inspections.

DO THE BACTIQUANT-SURFACE RESULTS CORRELATE TO HETEROTROPHIC PLATE COUNT (CFU)?

Under certain conditions, Yes. A dilution series of a known bacterial suspension under  laboratory controlled conditions  will give a  very good correlation (see figure below). However, it is not the general rule. When measuring total bacteria in an environmental sample with a high diversity of bacteria, often as little as 1% of the bacteria present may be culturable. Many variables such as the percentage of culturable bacteria in the environment, the nutrient agar used, time and temperature of incubation, as well as other things will affect the outcome of the plate count. Whereas, Bactiquant is not subject to these variables and provides a very consistent result.

HOW DOES THE BACTIQUANT-SURFACE METHOD COMPARE TO ATP BASED TECHNOLOGY?

The Bactiquant-surface does not correlate well with ATP based methods. ATP is present in all living organisms, in the cells, in exudates, and secretions. The hydrolase activity measured by the Bactiquant-surface method is a much more specific measure of total bacteria present. As an example: Slide a finger cross a surface. This will leave high amounts of ATP on the surface even though no bacterial hydrolase can be measured.

DOES BACTIQUANT-SURFACE RESULTS CORRELATE TO ENDOTOXIN LEVELS?

Endotoxin is present in all gram negative bacteria but not in gram positive. The hydrolase activity that is measured in the Bactiquant-surface method, is present in most all bacteria, both gram negative and gram positive bacteria. After flooding and sewage backflow, a high total number of bacterial species, both gram negative and positive are deposited on surfaces. So although there are differences in the subpopulations that the two methods measure there is still a reasonable correlation between the two methods (R2 = 0.6469, P<0.0001), see figure below.

The advantage of measuring the endotoxin compared to Bactiquant-surface in the indoor environment is that there is a substantial body of data that has been published concerning endotoxin and its direct  association with respiratory symptoms related to the indoor environment. The disadvantage of the endotoxin methodology is that quantification of endotoxin is extremely dependent of the extraction protocol used. Inter-laboratory variability of up to four orders of magnitude has been reported for replicate samples and has prevented the development of criteria.

The fact that there is a reasonable correlation between the hydrolase activity (Bactiquant-surface) and endotoxin and that Bactiquant-surface is a very reproducible methodology (e.g. no extraction procedure necessary) makes the Bactiquant-surface method a favourable technology. In addition,  Bactiquant-surface is much more rapid and can provide results onsite.

WHO CAN OPERATE THE BACTIQUANT-SURFACE METHOD AND WHAT TRAINING IS REQUIRED?

Almost anyone can learn to perform the analysis. All users of the Bactiquant-surface method  must complete a proficiency training program (4-5 hours). The comprehensive course covers all the steps of sampling and analysis and is followed by an exam. To pass the exam, at least 80 % of the questions must be answered correctly.

Bactiquant-surface Applications

  • Initial diagnostic assessment
  • Rapid remediation clearance testing
  • Pre/Post HVAC cleaning documentation
  • Healthy Building Assessments
  • Expedite disaster response damage assessment
  • Healthcare ICRA documentation
  • Routine maintenance cleaning confirmation