What if you found gas in the Lab tubes but none in the BGLB thow does this affect the EC test
If you found gas in the Lab tubes but none in the BGLB (Bromothymol Blue Lactose Broth) tubes, it could potentially affect the EC (Escherichia coli) test. The EC test is a common laboratory test used to determine the presence of E. coli bacteria in a sample.
During the EC test, both Lab tubes and BGLB tubes are inoculated with the sample being tested. The presence or absence of gas production in these tubes is typically used as an indicator of the presence of E. coli. E. coli is known to produce gas as a byproduct of its metabolic activities, such as fermentation.
The Lab tubes contain a lactose medium that supports the growth of E. coli. If gas is observed in these tubes, it suggests that E. coli is present and actively fermenting lactose to produce gas. This is a positive result.
On the other hand, if no gas is observed in the BGLB tubes, it suggests that E. coli is not producing gas, indicating a negative result for the presence of E. coli. The BGLB tubes contain additional nutrients and a pH indicator (bromothymol blue) that changes color when acid is produced due to lactose fermentation. If gas is produced, it lowers the pH, causing the bromothymol blue indicator to change color. However, if no gas is produced, the bromothymol blue remains the same color, indicating a lack of acid production and a negative result for E. coli.
Therefore, if you found gas in the Lab tubes but none in the BGLB tubes, it suggests that E. coli may be present but not actively fermenting lactose. This could potentially affect the interpretation of the EC test results. It might be necessary to perform additional tests or retest the sample using alternative methods to confirm the presence or absence of E. coli.