Hundreds of healthcare workers and patients are being contacted and tested for tuberculosis (TB) following a small outbreak of cases at St Vincent’s Hospital in Sydney.

Genomic sequencing has revealed that five people have been infected with an identical strain of drug-resistant TB so far, with four of these cases linked to the hospital cluster.

The cluster began when a man presented to St Vincent’s ED on 30 October last year to be treated for asthma and pneumonia.

Although the patient was highly infectious at the time, he was not diagnosed with TB until a month after the presentation.