Molecular diagnosis of a Mycobacterium chelonae infection

A 23-year-old female presented with enlarged cervical lymph nodes, and a di agnosis of nonspecific lymphadenitis with formation of pyogranulomas was re ndered. Despite an initial oral antibiosis and subsequent long-term intrave nous and oral antibiosis under hospitalized conditions, the;symptoms progre ssed. The lymph nodes became larger and then affected the cervical region b ilaterally. Her general condition worsened, and an exanthema of the extremi ties accompanied by a reactive arthritis occurred. Serological assays of va rious viral and bacterial markers and blood cultures were negative. Applica tion of a polymerase chain reaction (PCR) protocol allowing specific amplif ication of mycobacterial DNA revealed DNA of Mycobacterium chelonea in form alin-fixed, paraffin-embedded lymph node tissue. Sequencing of the PCR prod uct showed a 97% homology with the known Mycobacterium chelonae sequence. M odification of the antibiotic therapy with clarithromycin, imipenem and ami kacin resulted in a rapid regression of the symptoms. The clinical course, in combination with the difficulties in detecting the infectious agent, sup ports the usefulness of molecular pathological analyses specific for nontub erculous mycobacteria (NTM).