Antigen used in Weil-Felix reaction:
Ans. c (Proteus). (Ref. Textbook of Microbiology by Ananthnarayan, 7th/283)PROTEUS# Normal intestinal commensals and opportunistic.# Proteus mirabilis is the most important urinary and nosocomial pathogen.# Gram-negative, motile, pleomorphic, and non-capsulated rods.# Lactose non-fermenter; Urease producing; Phenylalanine deaminase +# "Swarming growth" with fishy/seminal odour.# Most strains are lactose negative, produce H,S, and demonstrate characteristic swarming motility on agar plates. P mirabilis is indole negative, whereas P. vulgaris and P. penneri are indole positive.# Certain non-motile proteus vulgaris strains (X strains) agglutinate by sera from typhus fever patients (heterophilic agglutination reaction) - basis of Weil-Felix reaction for diagnosing Rickettsial infections.# Strains 0X2, 0X19, OXK are used in agglutination test.# Alkalization of urine, in turn, leads to precipitation of organic and inorganic compounds, with the formation of struvite and carbonate-apatite crystals, the formation of biofilms on catheters, and/or the development of calculi.# Rx:- P. mirabilis is susceptible to most antimicrobials except tetracycline, polymyxin B, and tigecycline.- 4th-gen cephalosporins (eg.cefepime), amikacin, TMP-SMX have excellent activity against Proteus.The urinary tract is by far the most common site of Proteus infection, with adhesins, flagella, IgA protease, and urease representing the principal urovirulence factors.
E. coli
Hemophilus
Proteus
Staph
Bacteria