NSW Tuberculosis Surveillance Report 2023: Laboratory

​On this page

  1. Method of diagnosis of tuberculosis cases in NSW, 2023
  2. Drug susceptibility of culture confirmed cases in NSW, 2023
  3. Culture positive tuberculosis cases in NSW linked by whole genome sequencing
  4. Outcome of epidemiological investigation into links to other cases in a whole genome sequenced cluster in NSW, 2023
  5. Type of epidemiological link for cases in a whole genome sequenced cluster with a confirmed or possible link to another case in NSW, 2023

Method of diagnosis of tuberculosis cases in NSW, 2023

​Most TB cases are diagnosed through laboratory findings, with 69% of cases having a positive TB culture​ and 20% of cases having a positive PCR (without a positive culture). 

 

Drug susceptibility of culture confirmed cases in NSW, 2023

The majority of culture positive TB cases (87%) in NSW are fully sensitive to first line TB treatment. A small number of cases have either multi-drug resistance (MDR) (3%) or pre-extensively drug resistance (Pre-XDR) (<1%).​

Drug susceptibilityNumber of casesPercentage
Fully Sensitive to first line TB drugs30587%
Monoresistance: Isoniazid309%
Monoresistance: Rifampicin00%
Monoresistance: Ethambutol00%
Monoresistance: Pyrazinamide31%
Resistant to 2 or more first line TB drugs (but not MDR)1<1%
MDR
113%
Pre-XDR
1<1%
XDR
00%

Whole genome sequencing (WGS) cluster analysis, NSW, 2023

​Culture positive cases found to be linked to another NSW case by WGS are classified as being in a cluster. Linked cases are within 12 single nucleotide polymorphisms (SNPs) of another case in the same cluster. 


36 (10%)
Culture positive cases linked by WGS


30
WGS clusters
where new case was added

Outcome of epidemiological investigation into links to other cases in a WGS cluster in NSW, 2023

The first case in the cluster is the index case. Epidemiological investigations found a confirmed or possible link for 45% of cases in WGS clusters in 2023. A confirmed link is when there is direct contact between two cases while the first case was infectious in both place and time. A possible link is when there are similarities in place and time but a direct link is not identified when the first case was infectious. ​

Epidemiological linkNumber of casesPercentage
Index case13%
Confirmed link1131%
Possible link514%
Unknown link1233%
No plausible transmission within Australia1719%

Type of epidemiological link for cases in a WGS cluster with a confirmed or possible link to another case in NSW, 2023

​The most common type of link, when known, to another case in the cluster was household, family and close friend links (38% of cases), followed by community linked (25%). Community links can include sports, places of worship and other community groups. 

Type of link when possible/confirmedNumber of casesPercentage
Household, family, close friend638%
Community425%
Workplace521%
Other16%

Notes

  1. Case was not resident in Australia while earlier cases in the cluster were infectious.
  2. Data for this report was extracted from Notifiable Conditions Records for Epidemiology and Surveillance, NSW Ministry of Health on 24 September 2024. Additional data on whole genomic sequencing was extracted from TB WGS Epi REDCap Project Database.

Clinical presentation 2023 report Outcomes

Current as at: Thursday 19 December 2024
Contact page owner: Communicable Diseases