1. Traditional microbiological testing methods
Traditional methods are usually based on culturing bacteria in nutrient media, and include the steps:
- Preparing culture media (nutrient agar, MacConkey agar, Sabouraud agar, and so on).
- Inoculating the sample onto the medium.
- Incubating under suitable temperature conditions (usually 24–48 hours).
- Counting colonies or identifying bacterial morphology.
- Low sensitivity (depends on how well the organism grows). Limited specificity (genus/species).
* Advantages:
- Economical and easy to carry out in a basic laboratory.
- Allows observation of microbial growth and morphology.
- The gold standard for antibiotic susceptibility testing
* Disadvantages:
- Long testing time (24–72 hours).
- High risk of cross-contamination.
- Requires staff with precise technique.
- Cannot detect microorganisms that are hard to culture. Examples: plating on agar, Gram staining, biochemical tests (catalase, oxidase).
2. Modern microbiological testing methods
- Modern methods make use of advanced technologies such as PCR, ELISA, or automated systems to shorten testing time and improve accuracy.
* Advantages:
- Fast, shortening testing time.
- Highly accurate, detecting microorganisms rapidly.
- Reduces the risk of cross-contamination.
* Disadvantages:
- High investment cost.
- Requires accurate equipment and technicians.
- Can give false positives (DNA contamination). PCR/qPCR, genome sequencing (NGS), MALDI-TOF, ELISA, microarray.
Microbiological testing with Compact Dry plates (Shimadzu)
The Compact Dry plate is a rapid, integrated microbiological testing method developed by Shimadzu.
* How it works:
- A liquid sample is dropped directly onto the Compact Dry plate.
- The dry medium absorbs the liquid, allowing colonies to grow.
- After incubation, colonies can be counted easily.
* Advantages:
- Quick, convenient, no medium preparation needed.
- Reduces the risk of cross-contamination.
- Saves space and effort.
* Disadvantages:
- Limited for some particular microorganism types.
Traditional methods are still preferred in laboratories with limited resources, or when the viability of microorganisms must be determined (for example antibiotic susceptibility testing).
Modern methods suit requirements for speed, high accuracy, and large-scale analysis, especially in clinical diagnosis and research.
Future direction: combine both methods to optimize results (for example rapid PCR for screening, followed by culture for confirmation).
Both traditional and modern microbiological testing methods have their own characteristics. While traditional methods are easy to carry out and low in cost, modern methods deliver greater speed and accuracy. Among them, Compact Dry is an advanced solution that saves time and improves the efficiency of microbiological testing.