Extensive nosocomial transmission of tuberculosis in a low-incidence country

Abstract

Background: This paper describes a nosocomial outbreak of tuberculosis in a hospital ward where the number of cases with active tuberculosis among contacts was unexpectedly high. The outbreak was not revealed until the Mycobacterium tuberculosis genotyping results from the first two secondary tuberculosis cases were available.

Aim: To highlight the importance of correct infection control measures when tuberculosis is suspected.

Methods: A retrospective review of the contact investigations following the diagnosis of the index case admitted to the ward.

Findings: Seven contacts including three healthcare workers (HCWs) developed tuberculosis within 10 months after the death of a HIV positive patient from pulmonary tuberculosis. Six out of seven cases were verified by culture and all six M. tuberculosis isolates were confirmed by restriction fragment length polymorphism to cluster with the M. tuberculosis isolate from the index case. For the HCWs there was a correlation between number of working hours and risk of acquiring tuberculosis infection and disease.

Conclusions: It is essential that infection control guidelines regarding tuberculosis are followed, and that HCWs should continuously be informed about current tuberculosis control measures. All staff members at clinics treating tuberculosis cases should be screened for latent tuberculosis infection in order to have a reference, in case of future contact-tracing after accidental exposure to tuberculosis.