Analysis of enterococci using portable testing equipment for developing countries--variance of Azide NutriDisk medium...

Area of Science:

• Microbiology
• Environmental Science
• Water Quality Analysis

Background:

• Enterococci are key indicators of fecal contamination in water.
• Accurate enumeration of enterococci is crucial for assessing drinking water safety.
• Existing methods may have limitations in flexibility regarding incubation conditions.

Purpose of the Study:

• To compare the enterococci recovery efficiency of Azide NutriDisk (AND) and Slanetz and Bartley (SB) media.
• To evaluate the impact of variable incubation time and temperature on enterococci counts.
• To determine the suitability of AND medium for field testing in developing countries.

Main Methods:

• Membrane filtration technique was used for sample processing.
• Enterococci recovery was assessed on AND and SB media under varying incubation times (20-48 h) and temperatures (37-47°C).
• Results were compared to the AWWA standard method (44°C, 44 h) and confirmed using Kanamycin Aesculin Azide (KAA) agar.

Main Results:

• Azide NutriDisk (AND) medium showed higher enterococci enumeration than Slanetz and Bartley (SB) medium across tested temperatures (p < 0.001).
• AND medium demonstrated a survival threshold at 47°C and significant results at 20 h (p = 0.021).
• AND medium provided accurate results over a broader range of incubation times and temperatures.

Conclusions:

• Azide NutriDisk (AND) medium is a viable and flexible alternative to SB medium for enterococci monitoring.
• The adaptability of AND medium to different incubator technologies enhances its utility for field testing.
• AND medium is particularly suitable for drinking water quality monitoring in developing countries using field testing kits.