Mutations associated with in vitro resistance to bedaquiline in Mycobacterium tuberculosis isolates in Australia.

Genome-wide analysis of 517 Mycobacterium tuberculosis isolates from New South Wales, Australia, have identified previously reported and 8 new mutations in Rv0678 and atpE genes linked to in vitro resistance to bedaquiline, a new class of antimycobacterial drugs. These mutations were present in 2.9% of prospectively sequenced genomes but in 10.

Can colony-forming unit testing be used to extend the shelf life of BCG vaccines?

A recent shortage in supply of Bacille Calmette-Guérin (BCG), the live attenuated vaccine given to protect against tuberculosis (TB) caused major disruption to global vaccination programs. In this study, we assessed whether quantification of viable bacteria, could be used to inform the use of the BCG vaccine beyond its manufacturer-assigned expiration date. The viability of a single batch of BCG-Denmark was tested in three independent laboratories.

16S-23S Internal Transcribed Spacer Region PCR and Sequencer-Based Capillary Gel Electrophoresis has Potential as an Alternative to High Performance Liquid Chromatography for Identification of Slowly Growing Nontuberculous Mycobacteria.

Accurate identification of slowly growing nontuberculous mycobacteria (SG-NTM) of clinical significance remains problematic. This study evaluated a novel method of SG-NTM identification by amplification of the mycobacterial 16S-23S rRNA internal transcribed spacer (ITS) region followed by resolution of amplified fragments by sequencer-based capillary gel electrophoresis (SCGE). Fourteen American Type Culture Collection (ATCC) strains and 103 clinical/environmental isolates (total n = 24 species) of SG-NTM were included.

Whole Genome Sequencing Demonstrates Limited Transmission within Identified Mycobacterium tuberculosis Clusters in New South Wales, Australia.

Australia has a low tuberculosis incidence rate with most cases occurring among recent immigrants. Given suboptimal cluster resolution achieved with 24-locus mycobacterium interspersed repetitive unit (MIRU-24) genotyping, the added value of whole genome sequencing was explored. MIRU-24 profiles of all Mycobacterium tuberculosis culture-confirmed tuberculosis cases diagnosed between 2009 and 2013 in New South Wales (NSW), Australia, were examined and clusters identified.

Identifying Likely Transmission Pathways within a 10-Year Community Outbreak of Tuberculosis by High-Depth Whole Genome Sequencing.

Background: Improved tuberculosis control and the need to contain the spread of drug-resistant strains provide a strong rationale for exploring tuberculosis transmission dynamics at the population level. Whole-genome sequencing provides optimal strain resolution, facilitating detailed mapping of potential transmission pathways.

Methods: We sequenced 22 isolates from a Mycobacterium tuberculosis cluster in New South Wales, Australia, identified during routine 24-locus mycobacterial interspersed repetitive unit typing.

Antibiotic susceptibility of diverse Mycobacterium abscessus complex strains in New South Wales, Australia.

Members of the Mycobacterium abscessus complex are emerging pathogens of increasing importance, causing both respiratory and soft tissue infections, but precise speciation is problematic. This study was performed to examine the subspecies and antibiotic susceptibility of M. abscessus complex isolates collected during 2013 at the statewide New South Wales Mycobacterium Reference Laboratory (NSW MRL), Australia.

Genotype heterogeneity of Mycobacterium tuberculosis within geospatial hotspots suggests foci of imported infection in Sydney, Australia.

In recent years the State of New South Wales (NSW), Australia, has maintained a low tuberculosis incidence rate with little evidence of local transmission. Nearly 90% of notified tuberculosis cases occurred in people born in tuberculosis-endemic countries. We analyzed geographic, epidemiological and genotypic data of all culture-confirmed tuberculosis cases to identify the bacterial and demographic determinants of tuberculosis hotspot areas in NSW.

Epidemiology of Peripheral Lymph Node Tuberculosis and Genotyping of M. tuberculosis Strains: A Case-Control Study.

Background: This study examined potential risk factors of lymph node tuberculosis (LNTB), including phylogenetic lineages of Mycobacterium tuberculosis (MTB), in comparison to pulmonary tuberculosis (PTB) in a setting with an ethnically diverse population.

Methods: We conducted a case-control study at a major tuberculosis clinic in Sydney, Australia, which included all patients with peripheral LNTB seen at the clinic between 2000 and 2012. Controls were randomly selected patients with PTB seen at the same clinic during the study period.

Genome sequencing reveals novel deletions associated with secondary resistance to pyrazinamide in MDR Mycobacterium tuberculosis.

Objectives: Detection of pyrazinamide resistance in Mycobacterium tuberculosis isolates presents significant challenges in settings with no dominant clonal lineages, such as Australia. We assessed the utility of WGS versus standard PCR amplification assays for the characterization of pyrazinamide resistance in MDR-TB isolates identified in New South Wales, Australia, over an 8 year period.

Methods: PCR amplicon sequencing was used to identify molecular markers associated with antibiotic resistance in pyrazinamide-resistant MDR-TB isolates recovered by the New South Wales Mycobacterium Reference Laboratory between 2007 and 2014.

Tuberculosis in Australia: bacteriologically-confirmed cases and drug resistance, 2011. A report of the Australian Mycobacterium Reference Laboratory Network.

The Australian Mycobacterium Reference Laboratory Network collects and analyses laboratory data on new cases of disease caused by the Mycobacterium tuberculosis complex. In 2011, a total of 1,057 cases were identified bacteriologically; an annual reporting rate of 4.6 cases per 100,000 population.

Added value of whole-genome sequencing for management of highly drug-resistant TB.

Objectives: Phenotypic drug susceptibility testing (DST) for Mycobacterium tuberculosis takes several weeks to complete and second-line DST is often poorly reproducible, potentially leading to compromised clinical decisions. Following a fatal case of XDR TB, we investigated the potential benefit of using whole-genome sequencing to generate an in silico drug susceptibility profile.

Methods: The clinical course of the patient was reviewed, assessing the times at which phenotypic DST data became available and changes made to the therapeutic regimen.

Temporal dynamics of Mycobacterium tuberculosis genotypes in New South Wales, Australia.

Background: Molecular epidemiology of Mycobacterium tuberculosis, its transmission dynamics and population structure have become important determinants of targeted tuberculosis control programs. Here we describe recent changes in the distribution of M. tuberculosis genotypes in New South Wales (NSW), Australia and compared strain types with drug resistance, site of disease and demographic data.

Fluoroquinolone resistance in non-multidrug-resistant tuberculosis-a surveillance study in New South Wales, Australia, and a review of global resistance rates.

Background: Fluoroquinolones (FQs) are used for drug-susceptible tuberculosis (TB) in patients unable to tolerate first-line agents. Current trials are also investigating these drugs in empiric first-line TB therapy, to improve outcomes and allow for shortened treatment regimens. Widespread FQ use in the community has resulted in FQ resistance in many microorganisms, including Mycobacterium tuberculosis.

Improved identification of rapidly growing mycobacteria by a 16S-23S internal transcribed spacer region PCR and capillary gel electrophoresis.

The identification of rapidly growing mycobacteria (RGM) remains problematic because of evolving taxonomy, limitations of current phenotypic methods and absence of a universal gene target for reliable speciation. This study evaluated a novel method of identification of RGM by amplification of the mycobacterial 16S-23S rRNA internal transcribed spacer (ITS) followed by resolution of amplified fragments by capillary gel electrophoresis (CGE). Nineteen American Type Culture Collection (ATCC) Mycobacterium strains and 178 clinical isolates of RGM (12 species) were studied.

Rolling circle amplification for direct detection of rpoB gene mutations in Mycobacterium tuberculosis isolates from clinical specimens.

Rapid and accurate detection of multidrug resistance (MDR) in Mycobacterium tuberculosis is essential to improve treatment outcomes and reduce global transmission but remains a challenge. Rifampin (RIF) resistance is a reliable marker of MDR tuberculosis (TB) since by far the majority of RIF-resistant strains are also isoniazid (INH) resistant. We have developed a rapid, sensitive, and specific method for detecting the most common mutations associated with RIF resistance, in the RIF resistance determining region (RRDR) of rpoB, using a cocktail of six padlock probes and rolling circle amplification (RCA).

Potent antimycobacterial activity of the pyridoxal isonicotinoyl hydrazone analog 2-pyridylcarboxaldehyde isonicotinoyl hydrazone: a lipophilic transport vehicle for isonicotinic acid hydrazide.

The rise in drug-resistant strains of Mycobacterium tuberculosis is a major threat to human health and highlights the need for new therapeutic strategies. In this study, we have assessed whether high-affinity iron chelators of the pyridoxal isonicotinoyl hydrazone (PIH) class can restrict the growth of clinically significant mycobacteria. Screening a library of PIH derivatives revealed that one compound, namely, 2-pyridylcarboxaldehyde isonicotinoyl hydrazone (PCIH), exhibited nanomolar in vitro activity against Mycobacterium bovis bacille Calmette-Guérin and virulent M.

Phenotypically occult multidrug-resistant Mycobacterium tuberculosis: dilemmas in diagnosis and treatment.

Objectives: The clinical significance of the emergence of Mycobacterium tuberculosis (MTB) isolates that contain rpoB mutations (genotypic resistance), but are phenotypically susceptible to rifampicin (RIF G(R) P(S)), remains uncertain. The aim of this study was to determine the prevalence of MTB cases that demonstrate this discordant rifampicin resistance pattern and to establish whether these patients have poorer treatment outcomes with rifampicin-based regimens.

Methods: rpoB sequencing was performed on all MTB isolates demonstrating phenotypic resistance to one or more first-line antituberculosis agents (excluding rifampicin).

Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 2010. A report of the Australian Mycobacterium Reference Laboratory Network.

The Australian Mycobacterium Reference Laboratory Network collects and analyses laboratory data on new cases of disease caused by the Mycobacterium tuberculosis complex. In 2010, a total of 1,051 cases were identified by bacteriology; an annual reporting rate of 4.7 cases per 100,000 population.

Tuberculosis in Australia: bacteriologically confirmed cases and drug resistance, 2008 and 2009. A report of the Australian Mycobacterium Reference Laboratory Network.

There were 886 and 1,062 bacteriologically-confirmed cases of tuberculosis (TB) in 2008 and 2009, representing an annual rate of 4.1 and 4.9 cases per 100,000 population respectively.

Editor's choice: Implications of isoniazid resistance in Mycobacterium bovis Bacillus Calmette-Guérin used for immunotherapy in bladder cancer.

We report a case of sepsis from Mycobacterium bovis Bacillus Calmette-Guérin (BCG) with low-level isoniazid resistance following intravesical treatment for bladder cancer. Isoniazid resistance in BCG has therapeutic implications when it causes infections after intravesical instillation. For these circumstances, we propose some modifications to existing treatment guidelines for BCG infection.