Surveillance of multidrug-resistant tuberculosis in Taiwan, 2008-2019

Diagnosis and Treatment of Tubercular Uveitis in Taiwan - Consensus of Expert Panels

There is currently a lack of guidelines with regard to tubercular uveitis (TBU) management in Taiwan. We therefore propose an evidence-based consensus on the management for TBU. The Taiwan Ocular Inflammation Society conducted a meeting that included nine ophthalmologist and one infection disease expert that focused on three broad areas of (1) nomenclature for TBU, (2) assessment and diagnosis for TBU, and (3) treatment of TBU. Brief literature review on TBU diagnosis and management was conducted that informed this panel meeting in order to make decisions on each consensus statements. In terms of our results, a consensus statements and recommendations for the diagnosis and management of TBU were developed. This consensus statement provides an algorithmic approach toward diagnosing and managing TBU. These statements are meant to enhance but not replace individual clinician-patient interactions and to facilitate real-world clinical practice improvement in terms of TBU patients care.

Emerging insight of whole genome sequencing coupled with protein structure prediction into the pyrazinamide-resistance signature of Mycobacterium tuberculosis

Pyrazinamide (PZA) is considered to be a pivotal drug to shorten the treatment of both drug-susceptible and drug-resistant tuberculosis, but its use is challenged by the reliability of drug-susceptibility testing (DST). PZA resistance in Mycobacterium tuberculosis (MTB) is relevant to the amino acid substitution of pyrazinamidase that is responsible for the conversion of PZA to active pyrazinoic acid (POA). The single nucleotide variants (SNVs) within ribosomal protein S1 (rpsA) or aspartate decarboxylase (panD), the binding targets of POA, has been reported to drive the PZA-resistance signature of MTB. In this study, whole genome sequencing (WGS) was used to identify SNVs within the pncA, rpsA and panD genes in 100 clinical MTB isolates associated with DST results for PZA. The potential influence of high-confidence, interim-confidence or emerging variants on the interplay between target genes and PZA or POA was simulated computationally, and predicted with a protein structure modelling approach. The DST results showed weak agreement with the identification of high-confidence variants within the pncA gene (Cohen's kappa coefficient=0.58), the analytic results of WGS coupled with protein structure modelling on pncA mutants (Cohen's kappa coefficient=0.524) or related genes (Cohen's kappa coefficient=0.504). Taken together, these results suggest the practicable application of a genotypic-coupled bioinformatic approach to manage PZA-containing regimens for patients with MTB.

Genetic surveillance and outcomes of pyrazinamide and fluoroquinolones-resistant tuberculosis in Taiwan

BACKGROUND

Pyrazinamide (PZA) and fluoroquinolone (FQ), particularly moxifloxacin (MXF), are essential drugs in the World Health Organization (WHO) recommended short-course regimen to treat drug-susceptible tuberculosis (TB).

METHODS

To understand the extent of PZA and MXF susceptibility in general TB cases in Taiwan, we conducted retrospective analyses of 385 conservative Mycobacterium tuberculosis complex (MTBC) isolates identified from 4 TB laboratories in different regions of Taiwan. The case information was obtained from the TB registry. Genotypic drug susceptibility testing (DST) was performed by sequencing drug-resistance associated genes, PZA (pncA) and FQ (gyrA, and gyrB). Phenotypic DST was determined using the Bactec MGIT 960 system or the agar proportion method. Genotyping was carried out using spacer oligonucleotide typing.

RESULTS

In this study, 4.7% (18/385) cases' isolates harbored pncA mutations and 7.0% (27/385) cases' isolates harbored gyrA or gyrB mutation. Notably, pncA mutation was associated with Beijing family genotypes (P = 0.028), East African-Indian (EAI) genotypes (P = 0.047) and MDR-TB (P < 0.001). Whereas, gyrA or gyrB mutation was associated with EAI genotypes (P = 0.020) and MDR-TB (P = 0.006). In addition, a statistically significant difference was found between the favorable outcomes using active and inactive PZA (P = 0.009) in 38 case isolates with any pncA, gyrA, or gyrB mutation.

CONCLUSION

We concluded that routine PZA and FQ susceptibility tests are recommended for guiding the treatment of TB.