Evaluation of in-house optimized semi-nested PCR and EIA for direct detection of mycobacterial DNA in CSF.

A rapid and correct diagnosis of mycobacterial infections is important for effective patient treatment. Semi-nested-PCR with Fl-16 SOL, 16SOR and 16SNSR primers based on the 16S rRNA gene, under optimized conditions, can detect 499 bp amplified products from all tested mycobacteria. The assay could detect as little as 100 fg of mycobacterial DNA except for rapid growing mycobacteria, whose detection limits ranged from 1 ng to 10 pg. The specificities of the capture probes were assessed with 96 mycobacterial strains (22 species) and 33 nonmycobacterial strains (30 species). The specificities of pAll1, pTbc1 and pMar1 were 94%, 93% and 82%, respectively, and that of pAvi1, pInt1, pChe1 and pFor1 were 100%. The pTbc1 and pAvi1 were tested with DNA from 108 CSF samples, and the sensitivity and specificity of the detection method were 56% and 84% compared to culture and patient histories. The assay should be used for rapid detection and concurrent identification of slow growing mycobacteria without parallel conventional culture verification.

Failure of treatment for chronic Mycobacterium abscessus meningitis despite adequate clarithromycin levels in cerebrospinal fluid.

We report a case of posttraumatic meningitis due to Mycobacterium abscessus, treated initially with oral clarithromycin and intravenous amikacin plus intrathecal amikacin. Despite cerebrospinal fluid (CSF) levels of clarithromycin and amikacin in excess of their in vitro minimum inhibitory concentrations for the organism, the CSF cultures remained continuously positive for M. abscessus. To our knowledge, this is the first documented case of M. abscessus meningitis and the first report of measured CSF levels of clarithromycin in a patient with meningitis, showing that even therapeutic CSF levels of clarithromycin and amikacin might not be successful in eradicating M. abscessus meningitis.

Rapid diagnosis of bacterial meningitis by the detection of a fatty acid marker in CSF with gas chromatography-mass spectrometry and selected ion monitoring.

A chemical marker of bacterial meningitis was sought by comparing derivatives of sterile cerebrospinal fluid (CSF) with cultures of organisms in spinal fluid and artificial media. The technique of gas chromatography-mass spectrometry with selected ion monitoring (GC-MS-SIM) was used, optimised for the analysis of fatty acids. Twenty candidate ions were screened, and an ion of mass: charge ratio (m/e) 268 was chosen for detection in clinical specimens. The origin of this marker is unknown, but it is probably the molecular ion of a C16:1 fatty acid. In 135 clinical specimens of CSF examined, the m/e 268 ion was found to be a useful marker for the common organisms that cause bacterial meningitis, giving a sensitivity of 88% and a specificity of 98%. The method was more rapid and more sensitive than conventional microscopy and culture, but CSF containing coagulase-negative staphylococci, Mycobacterium tuberculosis, Cryptococcus neoformans and some other uncommon pathogens gave inconsistent results. Many organisms produced characteristic ion profiles with multiple-ion monitoring, and this method of chemical analysis holds promise for the rapid diagnosis of bacterial infections to genus or species level.

Simultaneous infection of the central nervous system with Cryptococcus neoformans and Mycobacterium intracellulare.

A 46-year-old woman with cryptococcal meningoencephalitis also had Mycobacterium intracellulare isolated from her cerebrospinal fluid. She was treated with amphotericin B,5-fluorocytosine, and antituberculous agents (isoniazid and rifampin). She gradually improved and was well, except for residual neurologic damage, three years after discharge from the hospital. No evidence of significant underlying disease has been found.