INTRODUCTION: Nocardiosis is an invasive disease caused by members of the aerobic Actinomycetes genus, found in soil and organic matter. There are approximately 500 to 1,000 cases a year in the United States. This is an underestimation because Nocardia is not a reportable disease. An increasing number of Nocardia infections have been noted in the past 20 years as a result of the increasing numbers of immunocompromised hosts and improvement in laboratory techniques (1).
CASE PRESENTATION: A 45-year-old gentleman presented with fever of 104F 8/06, severe pleuritic pain, cough, dyspnea and sweating for several days. Past medical history: asthma since childhood, long standing extensive pulmonary fibrosis secondary to stage 4 sarcoidosis diagnosed by TBB 1997, active pulmonary tuberculosis while in prison treated 08/04-08/05 with 4 medications, with repeated sputum AFB smears and cultures becoming negative on treatment. A left pleural effusion was noted on 1/06 for which thoracentesis demonstrated a transudate negative for all cultures. MEDICATIONS: prednisone 30 mg daily, hydroxychloroquine 200 mg and home oxygen. FAMILY HISTORY: positive for sarcoidosis in the older sister. SOCIAL HISTORY: denies tobacco, alcohol or drug abuse. HOSPITAL COURSE: 110/85, HR 132, temperature 103.4, RR 18 Diaphoretic, mild respiratory distress. Left lower lobe crackles, wheezing. LABS: WBC 16.9, Chest x-ray: Bilateral densities and left lower lobe large opacity. CT of chest: bilateral interstitial changes, loculated left pleural effusion. The patient was admitted for pneumonia. IV Moxifloxacin and ceftriaxone were started and prednisone continued. The patient subsequently developed chills, and greater tachycardia, and was transferred to ICU. He then underwent thoracotomy, decortication and drainage. Biopsy showed organizing fibrinous pleuritis with negative AFB and GMS. Antibiotic therapy now included streptomycin, Bactrim, acyclovir, Rocephin and Biaxin. Culture of pleural peel grew Norcardia species, which was identified by CDC as N cyriacigeorgica. Susceptibility testing showed the following: amikacin, (MIC 1 susceptible); imipenem, (MIC 8 intermediate) ceftriaxone, (MIC 2 susceptible); sulfonamides, (MIC 8 susceptible); amoxicillin/clavulanate (MIC 16/8 intermediate), Vancomycin (MIC > 32 resistant). Accordingly Bactrim was added. The patient improved clinically. Chest x-ray showed resolution of pleural effusion.
DISCUSSIONS: Nocardia cyriacigeorgica is a recently described species. Of Nocardia species, the most frequently involved in human infections are members of the Nocardia asteroides complex. The members of this complex were subclassified into six different drug susceptibility types. Numerous new species of the Nocardia asteroides complex have been recently described including N. cyriacigeorgica . This species corresponds to strains of drug pattern type VI. It has been rarely reported in human infections so far. Pulmonary nocardiosis can be acute, subacute, or chronic. Acute norcardiosis infection can present as an isolated lung abscess or necrotizing pneumonia. Cavitating lesions can cause empyema or complicated parapneumonic effusions. The indolent progression of nocardiosis mimics other chronic granulomatous infections or pulmonary malignancies. Medical therapy with Sulfonamide remains the initial treatment and the mainstay. Clinical improvement is noted in one week and antibiotic levels reveal excellent tissue penetration. Several other antibiotics have been reported to be successful, but tetracycline derivatives (eg, minocycline), aminoglycosides, and carbapenems (imipenem-cilastatin, meropenem) have been the safest and most effective alternatives. Surgical therapy is recommended in patients who have localized abscesses, including CNS or empyema.
CONCLUSION: Pulmonary nocardiosis can present as an acute, subacute, or chronic condition with many different clinical presentations. Disseminated nocardiosis can occur in any patient, but is usually present in immunosuppressed patients with predominant involvement of the meninges and brain tissue. Nocardia infections should be suspected when pulmonary, skin, or disseminated disease occurs in immunosuppressed patients.
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