title: Evaluation of two media and different plating techniques for enumeration of thermotolerant coliforms in river water.
abstract: Testing for evidence of faecal contamination in river water has been traditionally accomplished by enumeration of thermotolerant coliform bacteria. In this work, deoxycholate lactose and m-Endo Agar LES media were evaluated using different techniques. The colony count methods were pour plate technique on Deoxycholate Agar (DCL pour plate), spread plating on m-Endo Agar LES (ELS spread), and membrane filtration on m-Endo Agar LES (ELF filtration). Typical thermotolerant coliform colonies were analysed by conventional biochemical tests. The three matched pairs showed statistically significant differences (P < 0.05) by the Wilcoxon signed rank test. One hundred and twenty three isolates obtained on m-Endo Agar LES (65%) were confirmed as E. coli. Likewise, one hundred and twenty isolates obtained on Deoxycholate Agar (71%) were confirmed as E. coli. The results of this study showed that the matched DCL-ELF presented the smaller statistically significant difference (P = 0.042) so, DCL could be used as alternative to ELF.
authors.affiliation: Laboratorio de Microbiología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Argentina. ltamagnini@com.uncor.edu
authors.forename: L M
authors.initials: LM
authors.lastname: Tamagnini
authors.forename: R D
authors.initials: RD
authors.lastname: González
mesh_terms: D000362:Agar / Q000494:pharmacology; D001118:Argentina; D001431:Bacteriological Techniques / Q000379:methods*; D003470:Culture Media / Q000494:pharmacology*; D003840:Deoxycholic Acid / Q000494:pharmacology; D004755:Enterobacteriaceae / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification*; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D005374:Filtration; D006358:Hot Temperature; D007785:Lactose / Q000494:pharmacology; D045483:Rivers / Q000382:microbiology*; D014871:Water Microbiology; D014876:Water Pollution
chemical_list: D003470:Culture Media; D003840:Deoxycholic Acid; D000362:Agar; D007785:Lactose