Proteus-Providencia-Morganella group @ Gram negative rods, motile, aerobic and facultatively anaerobic @ Catalase positive, oxidase negative, @ Attack sugars fermentatively with gas production, phenylalanine positive @ Urea positive, citrate positive, gelatin positive.

PROVIDENCIA: @ Gram negative rods, motile, aerobic and facultatively anaerobic @ Catalase positive, oxidase negative, @ Attack sugar fermentatively with gas production, citrate positive @ Gelatin positive, urease negative, phenylalanine positive.

MORGANELLA: @ Gram negative rods, motile, aerobic and facultatively anaerobic. @ Catalase positive, oxidase negative, @ Glucose fermented with production of gas, phenylalanine positive @ urease positive, citrate negative, gelatin negative.

PROTEUS SPECIES: @ P. mirabilis. @ P. vulgaris. PROVIDENCIA SPECIES: @ P. rettgeri @ P. stuartii MORGANELLA SPECIES: @ M. morganii: The only one species of medical importance. No swarming

ANTIGENIC STRUCTURE: @ The cell wall (O) antigens of Proteus strains: OX-2, OX-19, & OX-K cross react with Rickettsia antigens and so are used in diagnosis of rickettsial infections by the Weil-­Felix test.

PATHOGENSIS: @ All group members are: # Very motile, Hence invade the tissue directly and seriously. # Proteus and Morganella are urease positive. This enzyme hydrolyses urea in urine, form ammonia, and leads to rise in urine pH. This causes: Formation of stones Multiplication of bacteria & renal failure

EPIDEMIOLOGY: @ Normal habitat: human colon, water, soil. @ From the colon they enter the urethra, specially in women. Diseases: @ UTI caused by all. @ Pneumonia, wound infections and septicaemia are caused by Proteus. @ Nosocomial and hospital infections are caused by P. mirabilis and Prov. rettgerii.

LABORATORY DIAGNOSIS: Specimens: @ Urine, sputum, swabs, blood. Microscopy: @ Gram negative rods, motile, no capsule. Culture: @ On Mac Conkey, blood and CLED agar. @ Proteus produces swarming on blood agar & inhibited by bile salts (Mac Conkey).

Biochemical Reactions: a) Lactose negative, glucose positive. b) Catalase positive, oxidase negative. c) Phenylalanine positive. d) Urea positive (Proteus & Morganella). e) Citrate positive (Proteus & Providencia f) Gelatin positive (Proteus only)--- API

Biochemical reactions of Proteus, Morganella, and Providencia species Urea Cit Ind Suc H2S PDA GG P.mirabilis + D - P.vulgaris M.morgani P.rettgeri P.stuarti Key: Urea = Urease test, Cit = Citrate test, Ind = Indole test, Suc = Sucrose fermentation, H2S = Hydrogen sulphide production, PDA = Phenylalanine deaminase test, GG = Gas from glucose fermentation, D = Different strains give different results

TREATMENT @ Antibiotic sensitivity is needed. @ Prot. mirabilis is treated by ampicillin @ Indole-positive species (Prot. vulgaris, Prov. rettgeri, Morg. morganii) are best treated by cefotaxime.