TY - JOUR
T1 - Analysis of enterococci using portable testing equipment for developing countries - Variance of Azide Nutridisk medium under variable time and temperature
AU - Godfrey, S.
AU - Watkins, J.
AU - Toop, K.
AU - Francis, C.
N1 - cited By 1
PY - 2006
Y1 - 2006
N2 - This report compares the enterococci count on samples obtained with Azide NutriDisk (AND) (sterile, dehydrated culture medium) and Slanetz & Bartley (SB) medium when exposed to a variable in incubation time and temperature. Three experiments were performed to examine the recovery of enterococci on AND and SB media using membrane filtration with respect to: (a) incubation time; (b) incubation temperature; and (c) a combination of the two. Presumptive counts were observed at 37, 41, 46 and 47 °C and at 20, 24, 28 and 48 h. These were compared to AWWA standard method 9230 C (44 °C, 44 h). Samples were confirmed using Kanamycin Aesculin Azide (KAA) agar. Friedman's ANOVA and Students t-test analysis indicated higher enumeration of enterococci when grown on AND (p=0.45) than SB (p=<0.001) at all temperatures with a survival threshold at 47 °C. Significant results for AND medium were noted at 20 h (p=0.021), 24 h (p=0.278) and 28 h (p=0.543). The study concluded that the accuracy of the AND medium at a greater time and temperature range provided flexibility in incubator technology making it an appropriate alternative to SB medium for monitoring drinking water using field testing kits in developing countries.
AB - This report compares the enterococci count on samples obtained with Azide NutriDisk (AND) (sterile, dehydrated culture medium) and Slanetz & Bartley (SB) medium when exposed to a variable in incubation time and temperature. Three experiments were performed to examine the recovery of enterococci on AND and SB media using membrane filtration with respect to: (a) incubation time; (b) incubation temperature; and (c) a combination of the two. Presumptive counts were observed at 37, 41, 46 and 47 °C and at 20, 24, 28 and 48 h. These were compared to AWWA standard method 9230 C (44 °C, 44 h). Samples were confirmed using Kanamycin Aesculin Azide (KAA) agar. Friedman's ANOVA and Students t-test analysis indicated higher enumeration of enterococci when grown on AND (p=0.45) than SB (p=<0.001) at all temperatures with a survival threshold at 47 °C. Significant results for AND medium were noted at 20 h (p=0.021), 24 h (p=0.278) and 28 h (p=0.543). The study concluded that the accuracy of the AND medium at a greater time and temperature range provided flexibility in incubator technology making it an appropriate alternative to SB medium for monitoring drinking water using field testing kits in developing countries.
U2 - 10.2166/wst.2006.458
DO - 10.2166/wst.2006.458
M3 - Article
SN - 0273-1223
VL - 54
SP - 127
EP - 134
JO - Water Science and Technology
JF - Water Science and Technology
IS - 3
ER -