title: Analysis of enterococci using portable testing equipment for developing countries--variance of Azide NutriDisk medium under variable time and temperature.
abstract: This report compares the enterococci count on samples obtained with Azide NutriDisk (AND) (sterile, dehydrated culture medium) and Slanetz and 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 degrees C and at 20, 24, 28 and 48 h. These were compared to AWWA standard method 9230 C (44 degrees 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 degrees 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.
authors.affiliation: Water and Sanitation Project, UNICEF, Madhya Pradesh, India. sgodfrey@unicef.org
authors.forename: S
authors.initials: S
authors.lastname: Godfrey
authors.forename: J
authors.initials: J
authors.lastname: Watkins
authors.forename: K
authors.initials: K
authors.lastname: Toop
authors.forename: C
authors.initials: C
authors.lastname: Francis
mesh_terms: D015169:Colony Count, Microbial; D003470:Culture Media; D003906:Developing Countries; D016983:Enterococcus / Q000254:growth & development / Q000302:isolation & purification*; D013696:Temperature
chemical_list: D003470:Culture Media