Beta-glucuronidase activities of fecal isolates from healthy swine.
Research has shown that various percentages of fecal Escherichia coli isolates obtained from healthy subjects may be beta-glucuronidase negative. The ability to detect beta-glucuronidase activity among fecal E. coli isolates from healthy subjects may be affected by assay conditions. A study was conducted in which agar and broth media containing 4-methylumbelliferyl-beta-D-glucuronide (MUG) were used to examine beta-glucuronidase activities of fecal isolates from healthy swine. Rectal swabs were plated on MacConkey agar plus 100 mg of MUG per liter (MAC-MUG) and incubated at 35 degrees C for 24 h. Each of 986 isolates picked from MAC-MUG was inoculated into duplicate tubes of lauryl tryptose broth plus 50 mg of MUG per liter (LT-MUG). One set of tubes was incubated at 35 degrees C and the other set of tubes was incubated at 44.5 degrees C. Gas production and hydrolysis of MUG, indicated by fluorescence when observed with UV light with a wavelength of 360 nm, were determined after incubation for 24 and 48 h. A higher percentage (P less than 0.01) of isolates was MUG positive at 44.5 degrees C than at 35 degrees C after 24 h of incubation in LT-MUG. A higher percentage (P less than 0.01) of isolates was MUG positive after 48 h than after 24 h of incubation at both 35 and 44.5 degrees C. A lower percentage of isolates (P less than 0.05) was observed to be MUG positive on MAC-MUG agar compared with their MUG reactions in LT-MUG at 35 and 44.5 degrees C. Approximately 89% of the isolates identified were beta-glucuronidase-positive E. coli. The largest proportion of MUG-positive E. coli was detected with LT-MUG at 35 degrees C after 48 h of incubation.
Jackson
L
L
Department of Animal Sciences, University of Kentucky, Lexington 40546-0215.
Langlois
B E
BE
Dawson
K A
KA
D000818:Animals; D001431:Bacteriological Techniques; D004926:Escherichia coli / Q000201:enzymology* / Q000302:isolation & purification* / Q000378:metabolism; D005069:Evaluation Studies as Topic; D005243:Feces / Q000201:enzymology* / Q000382:microbiology*; D005260:Female; D005285:Fermentation; D005960:Glucosides / Q000378:metabolism; D005966:Glucuronidase / Q000032:analysis*; D006923:Hymecromone / Q000031:analogs & derivatives / Q000378:metabolism; D007785:Lactose / Q000378:metabolism; D008297:Male; D013552:Swine / Q000382:microbiology*
D005960:Glucosides; C014110:4-methylumbelliferyl glucoside; D006923:Hymecromone; D005966:Glucuronidase; D007785:Lactose