Evaluation of two media and different plating techniques for enumeration of thermotolerant coliforms in river water.
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.
Tamagnini
L M
LM
Laboratorio de Microbiología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Argentina. ltamagnini@com.uncor.edu
González
R D
RD
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
D003470:Culture Media; D003840:Deoxycholic Acid; D000362:Agar; D007785:Lactose