Revised guidelines for Australian laboratories performing mycobacteriology testing

Abstract

Mycobacteriology laboratories play a key role in tuberculosis (TB) control by providing phenotypic and molecular diagnostics, by performing molecular typing to aid contact tracing, and by supporting research and similar laboratories in Australia’s neighbouring countries where TB is prevalent. The National Tuberculosis Advisory Committee (NTAC) published a set of laboratory guidelines in 2006 aiming to document the infrastructure, equipment, staffing and work practices required for safe high-quality work in Australian mycobacteriology laboratories. These revised guidelines have the same aims and have been through a similar extensive consultative peer-review process involving the Mycobacterium Reference Laboratory (MRL) network, the Mycobacterium Special Interest Group (SIG) of the Australian Society for Microbiology (ASM), and other relevant national bodies. This revised document contains several significant changes reflecting the publication of new biosafety guidelines and tuberculosis standards by various national and international organisations, technology developments – such as the MPT64-based immunochromatographic tests (ICTs) and the Xpert MTB/RIF assay, and updated work practices in mycobacteriology laboratories. The biosafety recommendations affirm the latest Australian/New Zealand Standard 2243.3: 2010 and promote a biorisk assessment approach that, in addition to the risk categorisation of the organism, also considers the characteristics of the procedure being performed. Using this biorisk assessment approach, limited manipulations, such as Ziehl-Neelsen (ZN) microscopy, MPT64 ICTs, and culture inactivation/DNA extraction for molecular testing, may be performed on a positive TB culture in a PC2 laboratory with additional features and work practices. Other significant changes include recommendations on the integration of MPT64 ICTs and novel molecular tests into TB laboratory workflows to provide rapid accurate results that improve the care of TB patients. This revised document supersedes the original 2006 publication. NTAC will periodically review these guidelines and provide updates as new laboratory technologies become available.

A case of severe Mycobacterium thermoresistibile pneumonia

“…Whilst human disease secondary to M. thermoresistibile is rare, it is also possible that it is under-recognized. M. thermoresistibile is notable for its thermotolerance with its optimal growth occurring between 37 and 45 C, and has been cultured in temperatures up to 60 C. 3,4 There could be inadequate culturing conditions as laboratories do not routinely incubate samples at temperatures greater than 40 C, 5,6 thereby leading to its lack of identification as the causative organism responsible for infection.…”

Sustained transmission over two decades of a previously unrecognised MPT64 negative Mycobacterium tuberculosis strain in Queensland, Australia: a whole genome sequencing study

“…A molecular assay should always be used to confirm or exclude the presence of MTB. 42 This will minimise the risk of misdiagnosing MPT64 negative strains, with delayed or inappropriate treatment supporting ongoing transmission and ‘diagnostic selection”, as demonstrated by rifampicin resistant strains in eSwatini missed by XpertMTB/RIF and XpertUltra. 43 Integration of routine WGS into public health surveillance will aid early cluster identification, highlight sub-lineages of concern and where relevant, identify antimicrobial resistance.…”

Review article: latent tuberculosis in patients with inflammatory bowel diseases receiving immunosuppression—risks, screening, diagnosis and management

“…Such treatment prevents reactivation and subsequent development of active TB infection, which carries a risk of significant morbidity and mortality 6 . Guidelines recommend screening for and treating LTBI in patients at high risk of reactivation or with a high likelihood of LTBI on the basis of epidemiological risk factors 7,8 . Treatment prevents the transmission of infection and is an essential component of eliminating TB in low‐incidence countries 9 .…”

“…6 Guidelines recommend screening for and treating LTBI in patients at high risk of reactivation or with a high likelihood of LTBI on the basis of epidemiological risk factors. 7,8 Treatment prevents the transmission of infection and is an essential component of eliminating TB in low-incidence countries. 9 Key determinants to accessing available regimens are geographic location and cost.…”