Rhodococcus Equi: A Pathogen in Immunocompetent Patients
A 38-year-old female came with a complaint of lump in the upper quadrant of the right breast since 9 days following a trauma 15 days back due to a fall. There was no history of pain or fever. There was no history of nipple discharge, nipple retraction or ulceration of skin. On local examination a lump was found in the upper outer quadrant of the right breast which was nodular and erythematous. The lump was tender and there was local rise in temperature. It was firm to hard in consistency. Anterior axillary lymph nodes were palpable. The patient's vitals and systemic examination were normal. Investigations showed a total leucocyte count of 9,400 cells/cumm with neutrophils 84%, lymphocytes 13%, eosinophils 1% and monocytes 2%. Random blood sugar was 87 mg/dl. The patient was found to be HBsAg reactive and HIV nonreactive. Liver function tests were within normal limits. Ultrasonography of the right breast showed mixed echogenic collection in upper and outer quadrant indicating either infected hematoma or abscess. Incision and drainage were done under general anesthesia and the pus was sent for microbiological investigations. She was given intravenous amoxicillin-clavulanic acid 1.2 g 8-hourly for 6 days.\nGram staining of the sample revealed numerous pus cells and a moderate number of irregularly stained gram-positive bacilli which were acid fast by 1% H2SO4 Zeihl--Neelson staining [] Culture on blood agar showed growth of 1--2 mm sized orange pigmented, nonhemolytic colonies [] after 48 hours of incubation. MacConkey's agar did not show any growth. On Gram staining they were irregular Gram-positive bacilli with diphtheroid morphology. It was identified as Rhodococcus equi by conventional biochemical tests. It was sensitive to ampicillin, amoxicillin-clavulanic acid, cephalosporins, gentamicin, erythromycin, ciprofloxacin.\nPatient was discharged on the seventh day with advice of oral amoxicillin-clavulanate 625 mg three times a day for 10 days.