A 36 years male presented with complain of productive cough and fever for last 2 months. Hehas undergone kidney transplantation 2 years back. His sputum examination revealed a grampositive filamentous bacteria that showed acid fastness with modified Ziehi-Neelsen staining(1% H2S04). The most likely etiological agent is ?
High-Yield Explanation
Ans. is 'b' i.e., Nocardia asterordes [Ref: Previous explanation)o Symptoms of pneumonia by a filamentous acid fast bacterium suggest the diagnosis of Nocardia.NOCARDIAMorphologyo Grant positiveo Acid fast (N. astroides and N. 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 manifestationTreatment* 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.