How does CENSUS-MST work?

CENSUS is based on a revolutionary molecular biological tool (MBT) called quantitative polymerase chain reaction (qPCR) whereby many copies of a specific gene are generated. As each gene copy is made, a fluorescent marker is released, measured, and used to quantify the number of target genes present in the sample. The gene copied during the process (target) is determined by short segments of DNA called “primers” which are added to the reaction mixture. In essence, qPCR is like a copy machine with a counter. The “primers” select which pages (target) of the book (DNA) are copied and the counter keeps a running total of how many pages were copied (number of target genes in the sample).

CENSUS Advantages

CENSUS offers many advantages over culture-based methods such as plate counts or most probable number (MPN) analyses that have traditionally been used to estimate bacterial populations in environmental samples. Traditional methods like plate counts and MPNs are dependent upon growth of the target microbial population on agar plates or liquid media in the laboratory. Despite advances in growth media, however, typically less than 10% and often less than 1% of the total population can be cultivated (grown) in the lab. Thus, traditional methods severely underestimate the true population.

CENSUS analysis on the other hand, utilizes DNA that is extracted directly from the sample, completely eliminating the need to grow the target organisms.

  • Accurate — DNA is extracted directly from the sample eliminating the need to grow the bacteria thus circumventing biases associated with more traditional based approaches like plate counts.
  • Specific — Targets either the specific bacterial group (e.g. sulfur reducing bacteria) or a specific gene encoding a desired function (e.g. nitrogen reduction).
  • Rapid — Results are available within days (7–10 standard TAT) with rush service available.
  • Sensitivity — Practical Detection Limits (PDL) as low as 100 cells per sample with a dynamic range over seven orders of magnitude.
  • Flexibility — Analysis can be performed on a variety of sample types including water, soil, sediment, Bio-Traps®, and others.  Please see Sampling for details.
  • Broad Applicability — CENSUS assays can target a broad range of organisms and microbial functions.
CENSUS Approaches

CENSUS is offered in a variety of formats to meet the objectives of your particular project.

CENSUS — Are general and source specific fecal bacteria present?

Our standard DNA based approach provides quantification of general bacterial groups and source specific fecal bacteria.