Diffuse meningo-encefalitys due to Nocardia farcinica in a young kidney transplant recipient: identification of the strain using sequencing of hsp65 gene

Abstract

Genus Nocardia belongs to aerobic Actinomycetes, a wide group of polymorphous Gram+, fixed and acapsusalated, branching, partially acid-fast bacilli. Nocardia organism are ubiquitous, soil-borne actinomycetes that usually infect humans as a result of the inhalation of airborne bacilli or traumatic inoculation. Nocardiosis is a rare opportunistic disease that affects mainly patients with impaired cellmediated immunity, such as those with acquired immunodeficiency syndrome (AIDS) or transplant recipients, patients with pulmonary disease, haematological malignancies etc. Pulmonary disease is the most common presentation in immounosuppressed patients. Nocardial organism have a tendency to disseminate hematogenously from the primary site of infection.The central nervous system (CNS) is one of the most frequent sites of dissemination. Herein we describe a rare and fatal case of diffuse meningo-encephalytis due to Nocardia farcinica in a young patient kidney transplant recipient. Nocardia has been isolated from Cerebrospinal fluid in a micobacteriology laboratory with identification of the strain using sequencing of hsp65 gene. The diagnosis can be challenging, as signs and symptoms are not specific and a high degree of clinical suspicion is required. Identification of Nocardia farcinica is important because of its aggressiveness, its tendency to disseminate, and its resistance to antibiotics. Susceptibilities to 10 antimicrobial agents were determined by E-test.The isolate was resistant to Gentamicin, Clarithromycin, Doxycicline, Cefotaxime and susceptible to Amikacin,Amoxicillin clavulanate, Imipenem, Ciprofloxacin, Linezolid and Trimethoprim–Sulfamethoxazole. The susceptibility profile was favourable since, in North Italy, the strains are generally resistant to Trimethoprim-Sulfamethoxazole.