A patient is suffering from pneumonia. Laboratory study shows acid-fast filamentous bacterium. The causative organism is -

Ans. is 'c' i.e., Nocardia o Symptoms of pneumonia by a filamentous acid fast bacterium suggest the diagnosis of Nocardia.NOCARDIAMorphologyo Gram positiveo Acid fast(N. astroidesandN. brasiliensis)o Crooked, branching, beaded, filamentous.Cultureo Use paraffin as a carbon source:o Paraffin baiting is used for isolation.o Strict aerobeo They take 2 weeks to appear and show their characteristic appearance at about 4 weeks.Clinical manifestationNocardia infectionRespiratoryExtra pulmonaryAfter transcutaneousKeratitiso Pneumonia is most commono Empyemao Lung abscesso S.V.C. syndromeo Pericarditiso M.C. site is braino Other organs: kidney bone muscleo Typical manifestation is subacute abscessinoculationo Cellulitis\o Lymphocutaneous syndromeo Actinomycetomao Usually byN. asteroides Treatment# Sulfonamide---Drug of choice# Cotrimoxazole---Equivalent# Minocycline---Best alternative# Amikacin---DOC for parenteral useRemembero N. asteroides is the species most commonly associated with invasive disease.