Pyogenic Liver Abscess Due to Rhodococcus equi in an Immunocompetent Host

Abstract

A case of pyogenic liver abscess (PLA) due to Rhodococcus equi in an immunocompetent individual was successfully treated by combining surgery and antibiotics. The R. equi-targeted antimicrobial agents erythromycin and rifampin were used only after surgical resection of the lesion and identification of the infective organism. CASE REPORTA 46-year-old man residing in the suburbs of the city of Rio de Janeiro, Brazil, was admitted to the university hospital with fever (39 to 40°C), right upper quadrant pain, nausea, vomiting, coluria, and weight loss (4 kg in 2 weeks). Abdominal ultrasound was done 2 months before hospitalization and revealed cholelithiasis. He had a history of hospitalization and blood transfusions due to gastric ulcers and melena episodes. He reported a smoking habit and sporadic alcohol ingestion. He denied having used illicit drugs and traveling to rural areas. He also denied hypertension, allergy, diabetes, tuberculosis, or other states of immunodeficiency. Clinical diagnosis revealed jaundice (1ϩ/4ϩ), paleness (2ϩ/4ϩ), tender hepatomegaly, and signs of dental infection. Abdominal ultrasonographic scanning procedures revealed the presence of two gallstones in the gall bladder and a 6-cm-diameter liver abscess with involvement of the upper and middle segments of the right lobe. There were no clinical or radiological evidences of brain, bone, or lung infection or pleural effusion. Blood samples were collected for bacteriological cultures, and empirical antimicrobial therapy was initiated with intravenous ampicillin, gentamicin, and metronidazole. In view of the clinical signs of purulent gingivitis and periodontitis, ampicillin was changed to penicillin G. Laboratory findings revealed anemia, leucocytosis (35,200 cells/l), and high levels of liver transaminases and phosphatase alkaline enzymes. The results of screening tests for human immunodeficiency virus and viral hepatitis were negative. On the fifth day after admission, there were still no significant clinical or radiological responses to antibiotics. Until day 25 of hospitalization, the patient remained afebrile with persistent abdominal pain. On day 26, the patient was found to be toxemic and feverish (38.4°C) and started vomiting green vomitus. The patient underwent percutaneous catheter drainage with ultrasound guidance, and 120 ml of chestnut-colored purulent secretion was collected from the abscess. Bacteriological cultures of the liver aspirate were negative. Penicillin G and gentamicin were changed to ceftriaxone and ampicillin. Follow-up of radiological and ultrasonographic scans of the liver indicated persistence of the abscess. Subsequent abdominal computed tomography confirmed the location of the abscess. Fifty days after admission, the patient underwent laparoscopy with drainage of the abscess and cholecystectomy. After surgical drainage and bacteriological identification of the infective organism, the patient was given R. equi-targeted antimicrobial therapy (erythromycin and rifampin) for 4 weeks. The patient was discharged fr...

Characterization of human clinical isolates of Dietzia species previously misidentified as Rhodococcus equi

“…It is also recognized as an opportunistic pathogen of humans, particularly in human immunodeficiency virus (HIV)-infected immunocompromised persons [1,2]. The traditional identification of R. equi in clinical laboratories is usually performed by the characterization of colony and microscopic morphology, and biochemical tests using a commercial kit such as the API Coryne [3][4][5]. However, the battery of traditional tests is not always sufficient for the accurate identification of R. equi because of its potential variation of colony and microscopic morphology or biochemical inactivity [3,4].…”

Identification of Virulence-Associated Plasmids in Rhodococcus equi in Humans with and without Acquired Immunodeficiency Syndrome in Brazil

“…14 However, little information is available in Brazil about virulence plasmid profiles of R. equi isolates from humans. [15][16][17] Intermediately virulent strains of R. equi are predominantly identified in HIV-positive patients, 2 the lymph nodes of pigs with and without lymphadenitis, 7,12 and, more recently, in lymph nodes of wild boars ( Sus scrofa ) in Hungary 10 and Brazil. 15 Furthermore, virulent R. equi strains also have been described in HIV-negative human patients.…”

Disseminated Rhodococcus equi infection in a patient with Hodgkin’s lymphoma

“…Extrapulmonal R. equi infection can be primary and secondary, and usually is a late manifestation of initial lung infection as was the case in our patient. It is a multisistemic or local disease, usually presented as sepsis, fever of unknown origin, cerebral abscess, meningitis, pericarditis, osteomyelitis, subcutaneous abscess, regional lymphadenitis, mastoiditis, or wound infection 18,25,27,[31][32][33][34][35][36] . Because of the delayed diagnosis and treatment, frequent bacteriemias and dissemination of R. equi infection, almost all of these manifestations were seen in our patient.…”