"Figure A.1: Flow chart. Specimens. Points to feces, tissues, milk, urine discharges, and various exudates. Points to (1) Yersinia spp. cold enrichment, (2) routine, and (3) Salmonella spp. Blood agar (BA) / MacConkey Agar points to incubate aerobically at 37°C for 24–48 hours. Points to colonies. Points to (1) no growth on MacConkey Agar (blood agar only) / not a member of the Enterobacteriaceae, and (2) growth on MacConkey Agar and on Blood Agar, gram-negative rods, fermentative (O-F Test). Oxidase negative. Points to Enterobacteriaceae (presumptive). Points to full identification, API 20E strip or conventional tests. Also points to reactions on MacConkey Agar, which can be either lactose-positive (pink colonies) or lactose-negative (pale colonies).\n\nColonial characteristics and/or biochemical tests of lactose positive: (1) Escherichia coli – IMViC test +/+/-/-, haemolytic on BA (some), mucoid (rare), (2) Klebsiella pneumoniae – Mucoid colonies non-motile, (3) Enterobacter aerogenes – Mucoid colonies motile, (4) Enterobacter agglomerans, Cronbacter sakazakii, Leclercia adecarboxylata, Escherichia hermannii (some lactose-) – yellow pigmentation, (5) Serratia rubidaea – red pigment produced best at 25°C.\n\nColonial characteristics and/or biochemical tests of lactose negative: (1) Salmonella spp. (most) – no odor, TSI R/Y/H2S +, lysine +, citrate +, (2) Edwardsiella tarda – TSI R/Y/H2S +, lysine +, citrate -, indole +, (3) Proteus vulgaris and Proteus mirabilis – swarming on BA, foul odor, H2S +, lysine -, urease +, phenylalanine +, (4) Morganella morganii – H2S -, lysine -, urease +, phenylalanine +, citrate -, (5) Providencia spp. – H2S -, lysine -, urease variable, phenylalanine +, citrate +, (6) Serratia marcescens – red pigment best at 25°C, a few produce it at 37°C, (7) Citrobacter diversus (some lactose +) – IMViC +/+/-/+, malonate +, urease +.\n\nFigure Reference: Figure A.1: Specimens. Under fair use and redrawn. Visit https://veteriankey.com/enterobacteriaceae to access the figure, resources, and other information."