Chronic pneumonia caused by Rhodococcus equi in a patient without impaired immunity

Abstract

A 48 year old, human immunodeficiency virus (HIV)-negative, immunocompetent male patient had a chronic progressive pulmonary infiltrate, without radiological cavitation, in the middle lobe of the right lung produced by Rhodococcus equi. He reported direct contact with a diseased dog.The patient was diagnosed by thoracotomy and treated by lobectomy. After 16 months of follow-up, the patient was asymptomatic and had neither recurrence nor immunological disturbances. Eur Respir J., 1997; 10: 248-250 There have been few reports of pulmonary infection caused by Rhodococcus equi in immunocompetent hosts. R. equi is a common pathogen in herbivores, particularly domesticated species. It rarely produces human disease, and infected subjects are usually persons with impaired immunity. Eleven cases of infection by R. equi in patients without impaired immunity have been reported in the literature, and four of these cases have involved pulmonary disease [1][2][3].We report the case of a patient with chronic progressive pulmonary infiltrate in the right middle lobe produced by R. equi. The patient treated by lobectomy. The characteristics of the case differed from those reported in other immunocompetent patients. Case reportA 48 year old male was referred to our hospital in August 1993 for investigation of a persistent pulmonary infiltrate with homolateral pleural effusion. He was a nonsmoker and had no medical history other than symptoms suggestive of gastro-oesophageal reflux.The patient's condition had arisen 10 months previously with 39°C fever, dry cough, and right pleuritic chest pain. He was diagnosed as having right basal pneumonia and treated with macrolides, leading to disappearance of the fever and improvement in the cough. He subsequently presented four similar clinical recurrences.Clinical exploration at admission disclosed a decrease in the vesicular murmur in the lower third of the right lung. Laboratory analyses disclosed decreased haemoglobin level (7.3 mmol·L -1 ) and haematocrit (0.37), and increased erythrocyte sedimentation rate (92 mm·h -1 ), and triglyceride (2.29 mmol·L -1 ) and glucose (6.38 mmol·L -1 ) levels. The leucocyte count (9.14 ×10 9 cells·L -1 ), formula, and other analytical parameters were normal. A tuberculin test was negative. Serological studies for respiratory viruses, mycoplasma, legionella, chlamydia, and other respiratory microorganisms showed no changes in titres. Human immunodeficiency virus (HIV) serology was negative.The patient's radiographs from 7 months earlier showed a well-delimited nodular image in the outer part of the right middle lobe, and involvement of the fissure and right cardiophrenic sinus. Computed axial tomography (CAT) performed 5 months before admission showed improvement in the nodular image, condensation in the right middle lobe, and discrete pleural thickening. A further CAT performed 1 month later showed disappearance of the nodular image, increased condensation and loss of volume in the right middle lobe. On admission, the radiograph and CAT of t...

Impacts of Rhodococcus equi on Acquired Immunodeficiency Syndrome: A Review

“…Of the 19 reported cases, localized infections accounted for nearly 50 %, including all infections in children. Pulmonary infection was present in 40 % of infected patients, and disseminated infection did occur [54]. Two immunocompetent patients (11 %) died of R. equi infection, although one had multiple medical comorbidities and the other was treated with inadequate antibiotics and died before R. equi infection was identified.…”

Chronic infections: causes and possible approach to treatment

“…doi: 10.7243/2052-5958-2-3 a high antibiotic resistance, or had immune deficiencies been invariably found in patients with chronic infections. However, there are many cases of chronic infections where the pathogens are sensitive to antibiotics and the immune system is normal [10][11][12][13][16][17][18][19][20][21][22].…”

Chronic Bacterial Pneumonia

“…Klebsiella pneumoniae (Friedländer's bacillus) was described as a common pathogen in chronic bacterial pneumonia (Solomon, 1940). Since 1967, original reports concerning chronic pneumonia have been limited to individual case descriptions (Essig et al, 1994;Henry, 1983;Linares et al, 1997;Ribas et al, 1997;Rose, 1968;Rubin et al, 1992). Reviews have focused on predisposing host diseases or nonbacterial pathogens (Carrizosa & McNamee, 1984;Dismukes, 1990).…”

“…Almost 100 cases of human infection with R. equi have been reported in the literature, 85% of which occurred in patients immunosuppressed due to AIDS, corticosteroid therapy, or chemotherapy (Linares et al, 1997) Pneumonia is the most common form of disease in humans, occurring in approximately two thirds of cases (Lasky et al, 1991;Vervilla et al, 1994). The organism is a pleomorphic gram-positive, intracellular bacillus that is an obligatory aerobe and may stain weakly acid-fast.…”

“…The organism is a pleomorphic gram-positive, intracellular bacillus that is an obligatory aerobe and may stain weakly acid-fast. R. equi is ubiquitous in soil and in the feces of herbivores, birds, and animals such as the dog (Linares et al, 1997;Prescott, 1991). A history of animal exposure is reported in half of the patients (Lasky et al, 1991).…”