Which organism is non-lactose fermenting, oxidase negative, nitrate positive, PAD positive, citrate negative, and indole positive?

Prepare for the CAMLPR Microbiology Test. Utilize flashcards and engaging multiple-choice questions, each equipped with descriptions and explanations. Ready yourself for an excellent performance!

Interpreting a biochemical profile helps you identify where an organism fits among Enterobacteriaceae. The combination here starts with a non-lactose fermenter, which already narrows the field to a few genera. Oxidase negative keeps it within the typical Enterobacteriaceae group. Nitrate reduction being positive is common in these bacteria, but the next clues are more discriminating: PAD (phenylalanine deaminase) positive points to Morganella and Providencia, separating them from many other non-lactose fermenters. Citrate is negative, which helps exclude Hafnia alvei, since Hafnia tends to be citrate positive. The indole test is positive, and among the remaining candidates, Morganella morganii is classically indole positive. Put together, the full pattern—non-lactose fermenting, oxidase negative, nitrate positive, PAD positive, citrate negative, indole positive—most closely matches Morganella morganii.