Biodegradable, effective substitute for xylene in the Ehrlich indole procedure.
Three extracting reagents were compared for effectiveness in the Ehrlich indole procedure: xylene (the recommended reagent), Hemo-De (a terpene-based product containing d-limonene), and Micro-Clear (an isoparaffinic hydrocarbon). Thirty-three strains representing 12 species of indole-positive aerobes or facultative anaerobes and 50 strains representing 11 species of indole-positive strict anaerobes were tested using the three reagents. Xylene extraction allowed indole detection in all of the isolates tested. Micro-Clear allowed detection in all of the aerobic isolates and in 49 of 50 anaerobes. Hemo-De allowed indole detection in 32 of 33 aerobes and in 49 of 50 anaerobes. There was no significant difference in the results among the reagents. Because Micro-Clear is biodegradable, nonflammable, noncarcinogenic, and odorless, we feel that this product should be considered a safe and effective substitute for xylene in the Ehrlich indole procedure.
Miller
J M
JM
Diagnostic Microbiology Section, Centers for Disease Control and Prevention, Atlanta, GA 30333.
Miller
M D
MD
Driscoll
P E
PE
Miller
P
P
D015373:Bacterial Typing Techniques; D001547:Benzaldehydes; D001673:Biodegradation, Environmental; D006090:Gram-Negative Bacteria / Q000145:classification*; D006256:Hazardous Waste; D007202:Indicators and Reagents; D007211:Indoles / Q000032:analysis*; D010232:Paraffin; D012997:Solvents; D013729:Terpenes; D014992:Xylenes
D001547:Benzaldehydes; D006256:Hazardous Waste; D007202:Indicators and Reagents; D007211:Indoles; D012997:Solvents; D013729:Terpenes; D014992:Xylenes; C051809:Hemo-De; C090792:Micro-Clear; D010232:Paraffin; C030374:indole; C510241:p-dimethylaminobenzaldehyde