agar and Colitis

A new and rapid ( < 1 h) enzyme-linked immunosorbent assay (ELISA) was compared with conventional sorbitol-MacConkey agar (SMAC) culture for the detection of Escherichia coli O157 from stool specimens. Among 34 positive specimens, confirmed by colony-sweeping and immunofluorescence stain methods, 6 did not exhibit visible sorbitol-negative colonies on SMAC. These six specimens would have been considered to be negative if SMAC alone had been used. The ELISA detected 31 of the 34 positive samples, including 5 of the above-mentioned 6 false-negative samples, resulting in a sensitivity and specificity of 91.2 and 99.5%, respectively. Cross-reactivity with other enteric pathogens was not noted by ELISA. The SMAC method had a sensitivity and specificity of 82.4 and 100%, respectively. The ELISA-negative specimens do not require culture confirmation, whereas positive results must be considered to be presumptive until confirmed by culture. The test is accurate and is easy to perform, making it a very efficient method for screening stool specimens for E. coli O157.

Topics: Agar; Bacteriological Techniques; Colitis; Culture Media; Diagnostic Errors; Enzyme-Linked Immunosorbent Assay; Escherichia coli; Escherichia coli Infections; Evaluation Studies as Topic; Feces; Humans; Sensitivity and Specificity; Sorbitol

By combining the enterohemolysin test and the VTEC-RPLA test (specific for the detection of Shiga-like toxin I [SLT-I], SLT-II, and SLT-IIc), single colonies of SLT-producing Escherichia coli were found to constitute between 0.03 and 68.1% of the coliform flora in human stool cultures and were isolated and characterized within 72 to 96 h.

Topics: Agar; Animals; Bacterial Toxins; Bacteriological Techniques; Blood; Colitis; Escherichia coli; Escherichia coli Infections; Evaluation Studies as Topic; Feces; Hemolysis; Hemolytic-Uremic Syndrome; Humans; Latex Fixation Tests; Sheep; Shiga Toxin 1

Topics: Adult; Agar; Aged; Anemia; Blood Proteins; Breast Neoplasms; Bronchitis; Colitis; Electrophoresis; Female; Gels; Humans; Infections; Inflammation; Male; Middle Aged; Neoplasms; Orchitis; Pneumonia; Testicular Neoplasms