Uncommon nosocomial transmission of TBC in an outpatient clinic in 2005: possible route of pathogen

Abstract number: P802

Eckmanns T., Epple H., Karcher H., Buchholz P., John P., Schneider T.

Objectives: We report an uncommon nosocomial transmission of Mycobacterium tuberculosis in an outpatient ear, nose and throat (ENT) clinic. The first patient suffered from an acute otitis media. The second patient complained about sudden deafness. The index patient was diagnosed with tuberculosis otitis media 3 months after the initial diagnosis. The second patient was diagnosed with tuberculosis otitis media 5 months after the initial diagnosis and 3 months after the index patient.

We investigated the contact situation regarding the two patients and the probable route of transmission.

Methods: The case histories were checked for possible contact between the two patients. The similarity of the pathogens was investigated by molecular methods. The hygienic situation of the outpatient clinic was audited and the hygienic plausibility of the transmission of the pathogens was investigated by laboratory experiments. Potential other contacts in the clinic were traced back and investigated using a t-cell based assay (Elispot) for IFN-gamma.

Results: Both patients met once in the ENT clinic. Both had an invasive ear examination on this day. Microbial investigation revealed the same clonal pattern.

The audit revealed incomplete compliance with hygienic necessities, especially concerning hand disinfection and environmental disinfection between different consultations (e.g. contact to ear microscope). In addition, staff reported that the rinse water of the ear suction device was not changed between consultations. An experiment proved a possible contamination of the suction device by contaminated rinse water. A second experiment showed that the flyback of rinse water in the upside down hanging suction device was able to contaminate the apex of the device.

None of the 10 contacts, who were treated in the ENT clinic on the same day revealed a positive result in the Elispot.

Conclusion: Investigations demonstrated probable transmission in the outpatient clinic. Different routes of transmission are possible. A lecture in hand disinfection was given and a new hygienic management was established which included systematic disinfection of patient environment between consultations. In addition structural changes like a hanger for the suction device were established. Hygienic management is a challenge in ENT clinics, as patient turnover is high, infectious disease are common and many medical devices are used.