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_ An AIDS patient develops symptoms suggestive of a severe, persistent pneumonia with cough, fever, chills, chest pain, weakness, and weight loss. The patient does not respond to penicillin therapy, but goes on to develop very severe headaches. The presence of focal neurologic abnormalities leads the clinician to order a CT scan of the head. This demonstrates several metastatic brain abscesses. Biopsy of one of these lesions demonstrates beaded, branching, filamentous gram-positive bacteria that are weakly acid fast. Which of the following is the most likely causative organism?
A. Actinomyces
B. Aspergillus
C. Burkholderia
D. Francisella
E. Nocardia
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good... thank you...I am fine
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The correct answer is
E.Nocardia asteroides is an aerobic soil saprophyte that can cause acute or chronic infectious disease often characterized by granulomatous-suppurative lesions that may become widely disseminated. Many, but not all, patients have underlying causes for immunodeficiency, including advanced age, lymphoreticular malignancies, organ transplantation, high dose corticosteroid therapy, or (increasingly commonly) AIDS. Disseminated nocardiosis usually starts as a pulmonary infection that can resemble either a severe pneumonia or tuberculosis. Once dissemination occurs, metastatic brain abscesses are particularly common, occurring in as many as 1/3 of patients with nocardiosis. Nocardiosis is treated with sulfa drugs, such as sulfadiazine or trimethoprim-sulfamethoxazole, for periods of months.
Actinomyces (choice A) is very similar to Nocardia, but is not acid-fast.
Aspergillus(choice B) is a fungus.
Burkholderia(choice C)pseudomallei is a gram-negative bacillus that causes melioidosis, which is characterized by lung involvement or disseminated infection.
Francisella(choice D)tularensis causes tularemia, which is usually acquired by contact with infected wild rabbits.
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correct.....also nocardia is only one which is a weak acid fast bacilli[partially acid fast bacilli]
