A 50 year old chronic alcoholic male agricultural worker presented with high grade fever of one week duration with spells of chills and rigor. Examination of the respiratory system revealed bilateral crepitations with scattered rhonchi. Multiple subcutaneous nodules were found on the extensor surface of the left forearm, arm and left leg. Direct microscopy of the pus aspirated from the skin nodule revealed plenty of Gram negative bacilli with bipolar staining. Culture revealed distinct rough corrugated grey-white colonies on Blood agar. The organisms were motile and oxidase positive. The most likely diagnosis is -
Ans. is 'b' i.e., Meliodosis . According to Harrison the diagnosis of Meliodosis should be suspected in the following patients: Febrile patient in endemic area presenting with acute lower respiratory tract illness associated with tachypnea. Unusual skin or subcutaneous lesions (acute localized suppurative skin infections associated with nodular lymphangitis.) Chest radiograph suggesting T.B. in the absence of sputum associated tubercle bacilli. About other options ? Plague - is easily ruled out as Yersinias are non motile and oxidase negative, but remember that when Yersenias are stained with (Wayson or Giemsa) they give a bipolar appearance resembling closed safety pins (Harrison I 5th/e page 993). . Baonellosis - It is an infection caused by gram negative bacilli Baonella bacilliformis. - They can be easily ruled out as they don't give bipolar safety pin appearance. The clinical presentation is also quiet different. - In baonellosis there is abrupt onset of fever followed by sudden development of profound anemia. . Actinomycosis : No confusion as Actinomycetes are gram positive organisms.
Plague
Melioidosis
Baonellosis
Actinomycosis