Nosocomial transmission of tuberculosis to a nurse demonstrated by means of spoligotyping of a formalin-fixed bronchial biopsy

Abstract

Background: Tuberculosis was diagnosed in a student nurse. The source of infection was unknown and no positive culture was available.

Methods: The diagnosis of tuberculous bronchitis was established on the grounds of a positive Mantoux test, the pathology of a bronchial biopsy and the results of a CT scan of the thorax. Spoligotyping of, for example, formalin-fixed tissue makes it possible to establish the diagnosis in a later phase after all.

Results: Cultures for Mycobacterium tuberculosis were not performed for the student nurse and Ziehl-Neelsen staining of the formalin-fixed bronchial biopsy was negative. The final tuberculosis diagnosis was confirmed by a PCR fingerprint technique, i.e., spoligotyping of a formalin-fixed biopsy specimen. By means of contact investigation and identification of the strain via spoligotyping, comparison of the spoligo patterns made it possible to treat both the patient and those infected by this person correctly.

Conclusions: When there is a pronounced suspicion of tuberculosis and a microbiological culture is not available, it is recommended that supplementary spoligotyping of clinical specimens be carried out. The purpose is to confirm the diagnosis, trace the presumed source case and indirectly to provide information on the drug susceptibility of the relevant M. tuberculosis strain.