Micro-organism Analysis

Analysis of Micro-Organisms with the qNano from Izon

Table of Contents

Introduction

Comparison of Microbiology Detection Methods

Table 1. Examples of Micro-organisms measured on the qNano

Example 1: Simultaneous Determination of Microbial Size & Titre

Example 2: Effect of Ethanol on Bacterial Cell Count

Conclusion

Major Features of the qNano

Introduction 

Counting microorganisms accurately and reliably is critical in many applications such as health and safety as in water treatment systems monitoring, the food and beverage industry, microbiology research, and industrial processes. However, traditional methods for counting microbial cells have some limitations in their accuracy and the time required for analysis.

qNano is a particle-by-particle counting and size analysis method for microorganisms. This method is proven to be fast, cost-effective, and to provide major advantages in accuracy compared to conventional measurement techniques. Analyses discussed here span bacterial cells and yeast. However, the qNano/qViro platforms also offer a quick and accurate tool for viral samples and titration analysis.

Comparison of Microbiology Detection Methods 

Commonly used techniques for counting bacteria involve plating and incubation to estimate the number of colony forming units (CFUs) or fluorescence-based assays. Plating is laborious and need several days to yield results. Petri dishes and other such plate formats are counted manually or loaded into readers for analysis.

Dedicated microbiology labs may use flow cytometry, which allows cell-by-cell analysis by suspending individual particles in a flow stream that passes through an excitation light source, typically a laser beam. The combined use of a fluorescent dye allows various parameters to be detected. This technique relies on the scattering of light and while it allows cell counting, a number of researchers have found this technique not sufficiently sensitive for measuring the changes in the size of small cells.

qNano is an established platform for particle-by-particle sizing and concentration determination with improved accuracy over other detection methodologies. It allows rapid and cost effective determination of microbial size, size distribution and concentration, in a portable device that can easily fit in fume hoods or biological safety cabinets and experiments can be performed during normal laboratory procedures. For examples of Micro-organisms analysed so far, See Table 1.

Table 1. Examples of Micro-organisms measured on the qNano 

Click on the links to go to the particular example.

Example 1: Simultaneous Determination of Microbial Size & Titre 

The qNano provides a rapid and highly accurate method for simultaneous determination of microbial particle size and titre in a single measurement. Shown below are the particle size distributions and concentration values for Lactobacillus spp. and Prochlorococcus, as determined using the qNano.

Figure 1. Particle size distribution and concentration value (inset) for probiotic consisting of Lactobacillus spp.

Figure 2. Particle size distribution and concentration value (inset) Prochlorococcus, a marine bacterium.

 Example 2: Effect of Ethanol on Bacterial count 

Accurate cell counting allows precise measurement of the cytotoxicity of the compounds present on bacterial cell populations. The results given below depicts the cell killing effects after ethanol exposure. A rod-shaped, Gram negative bacterium, Proteus vulgaris was exposed to different concentrations of Ethanol (EtOH) for 15 minutes at 37°C, and then studied with the qNano.

Figure 3 (A-C). qNano Analysis of Proteus Vulgaris after exposure to different ethanol (EtOH) concentrations. A steep drop-off in particle rate is observed after 50% EtOH exposure.

Figure 4. Comparison of Colony Forming Unit (CFU) count (yellow line) and Particle Rate (blue bars) at increasing ethanol concentrations.Particle rate gives an indication of the total particle count (including non-viable particles) whereas CFU count indicates viable viral particles only. At 25% EtOH for example, while particle count (blockade rate) is maintained, none of the bacterial particles result in viable colonies. This indicates a sharp drop-off in viability prior to rupture or lysis of bacterial cells.

Distinction between Microorganisms 

The results illustrated in the below graphs show a comparison between Proteus vulgaris and Saccharomyces cerevisiae, analysed with the help of qNano platform.

Conclusion 

qNano offers a rapid, cost-effective and extremely accurate method for microbial size and concentration determination.

Major Features of the qNano 

The key features of qNano are the following:

• Accuracy of analysis: Accurate measurement of total microbial titre and particle-by-particle size distribution
• Rapid: Fast analysis compared to conventional methods
• Real-time measurements: Effectiveness monitoring of bactericides due to real time volume changes
• Robustness and portability: Fits into biological safety cabinets; ability to perform experiments under normal laboratory conditions.