Pseudonocardia carboxydivorans in human cerebrospinal fluid: a case report in a patient with traumatic brain injury

Abstract

Background: Members of the genus Pseudonocardia have been widely reported and recovered from several ecosystems, such as soil samples and plant samples. Pseudonocardia bacteria colonize the microbial communities on the integument of fungus gardening ant species. We present the first documented case of Pseudonocardia carboxydivorans isolated in human cerebrospinal fluid (CSF). To the best of our knowledge, this is the first report of an human infection by P. carboxydivorans.

Case presentation: A patient, who suffered a traumatic brain injury a month before, was admitted to this hospital due to gait alteration and cognitive disturbances. Culture of cerebrospinal fluid showed ramified, not acid-fast, Gram positive bacilli. The bacterium was identified by molecular methods as P. carboxydivorans.

Conclusion: This is the first documented case of isolating P. carboxydivorans in human CSF in a case of probable meningitis. Further research is needed in order to determine its pathogenic role in human infections.

Keywords: Carboxydobacteria; Human cerebrospinal fluid (CSF); Pseudonocardia carboxydivorans; Traumatic brain injury (TBI).

Fig. 1

Microbiologic outcomes in cerebral spinal fluid. Panel a shows the culture of the specimen obtained from SCF the patient on selective medium for Legionella (BCYE) showing growth of white, dry and rough colonies after 7 days of incubation at 37 °C and 5% CO2 atmosphere. Panels b and c show the microscopic examination of the colonies by Gram and Kinyoun modified strain, showing the presence of ramified, not acid-fast, Gram-positive bacilli. The bacterium was identified by molecular methods of RNAr 16S sequencing, being finally identified as Pseudonocardia carboxydivorans in the National Center of Microbiology (ISCIII, Madrid, Spain)