Concise and efficient external environment water Legionella test technology

Foreword
Legionella monitoring and testing has been expensive, cumbersome, and inefficient.
In order to make it simple, easy and efficient, we need to solve three problems.
Three Problems in Legionella Test
1. The establishment of concise and effective inspection procedures.
2. Stable supply of complete sets of Legionella inspection products (guaranteed quality and reasonable price).
3.(high quality, high efficiency and reasonable price) membrane filter solution.
Brief introduction of a concise and efficient external environment water Legionella culture and isolation procedure:
Sampling: 300ml (air conditioning water);1-5L (drinking water)
The amount of water actually passing through the filter membrane: 300 ml of air conditioning water; 1000 ml of drinking pipe water.
Concentration: use a qualified filter (preferably with a negative pressure three-head filter) to filter and then cut the filter membrane. Add 3 ml of raw water and put on the shaker for 30 seconds.
Acid treatment: 1 ml of the above filtered water +1 ml of calibrated acid, mixed and then acted for 5 minutes. Then take 0.1 ml from it and inoculate GVPC agar plate (after pushing dry at 1/3 of the plate, separate by streaking at the other 2/3).
Culture: Place the GVPC agar plate in a CO2 incubator or a candle jar at 36°C for 4 to 6 days.
Screening: Pick suspicious (gray-blue, smooth and shiny) colonies, and spot GVPC agar plate and blood agar plate at the same time (10-20 colonies can be spotted on each plate). Cultured at 36 ℃ for 2~4 days, the bacteria that did not grow at all on the blood plate and the GVPC plate grew well were retained.
Preliminary identification:
o colony morphology like.
o Blood agar does not grow at all.
oG(-) Bacilli
Note:
1. Isolation of multiple Legionella species from the same specimen:
3-5 colonies can be selected from each plate for serotyping of Legionella on slides (about 1/4 of the air-conditioning water samples may isolate Legionella with more than two serotypes. For this reason, Legionella typing serum capable of typing each Legionella type, especially Legionella pneumophila type 1-8, must be used.).
2. Quantitative report (this operating procedure and our calibrated acid treatment solution must be used):
Using the calibrated acid solution for acid treatment, the quantitative report of the number of Legionella in the specimen (the number of viable Legionella per milliliter of water) can be made according to the number of Legionella colonies and a simple formula.
Formula 1: number of viable Legionella bacteria per milliliter of water = number of Legionella colonies on the plate ÷ 2.5 (this formula is applicable when the amount of specimen water filtered by the filter membrane is fixed at 300 milliliters).
Formula 2: number of viable Legionella per milliliter of water = number of Legionella colonies on the plate ÷(X ÷ 120) (this formula is applicable when the amount of specimen water filtered by the filter membrane is not fixed).
Note: X = milliliters of water sample actually passing through the filter membrane in Equation 2.
Avoid sodium ions:
Sodium ions have a significant inhibitory effect on the growth of Legionella. Therefore, the use of sodium ion-containing reagents such as physiological saline (distilled water may be substituted) must be avoided throughout the assay.

Shanghai Comaga Microbiology Co., Ltd
Chen Changyi