Molecular architectures of iron complexes for oxygen reduction catalysis-Activity enhancement by hydroxide ions coupling.

Developing cost-effective and high-performance electrocatalysts for oxygen reduction reaction (ORR) is critical for clean energy generation. Here, we propose an approach to the synthesis of iron phthalocyanine nanotubes (FePc NTs) as a highly active and selective electrocatalyst for ORR. The performance is significantly superior to FePc in randomly aggregated and molecularly dispersed states, as well as the commercial Pt/C catalyst. When FePc NTs are anchored on graphene, the resulting architecture shifts the ORR potentials above the redox potentials of Fe2+/3+ sites. This does not obey the redox-mediated mechanism operative on conventional FePc with a Fe2+-N moiety serving as the active sites. Pourbaix analysis shows that the redox of Fe2+/3+ sites couples with HO- ions transfer, forming a HO-Fe3+-N moiety serving as the ORR active sites under the turnover condition. The chemisorption of ORR intermediates is appropriately weakened on the HO-Fe3+-N moiety compared to the Fe2+-N state and thus is intrinsically more ORR active.

Surge of severe acute respiratory syndrome coronavirus 2 infections linked to single introduction of a virus strain in Myanmar, 2020.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a major health concern globally. Genomic epidemiology is an important tool to assess the pandemic of coronavirus disease 2019 (COVID-19). Several mutations have been reported by genome analysis of the SARS-CoV-2. In the present study, we investigated the mutational and phylogenetic analysis of 30 whole-genome sequences for the virus's genomic characteristics in the specimens collected in the early phase of the pandemic (March-June, 2020) and the sudden surge of local transmission (August-September, 2020). The four samples in the early phase of infection were B.6 lineage and located within a clade of the samples collected at the same time in Singapore and Malaysia, while five returnees by rescue flights showed the lineage B. 1.36.1 (three from India), B.1.1 (one from India) and B.1.80 (one from China). However, there was no evidence of local spread from these returnees. Further, all 19 whole-genome sequences collected in the sudden surge of local transmission showed lineage B.1.36. The surge of the second wave on SARS-CoV-2 infection was linked to the single-introduction of a variant (B.1.36) that may result from the strict restriction of international travel and containment efforts. These genomic data provides the useful information to disease control and prevention strategy.

Pyrazinamide resistance and pncA mutations in drug resistant Mycobacterium tuberculosis clinical isolates from Myanmar.

Pyrazinamide (PZA) is an important anti-tuberculosis drug, which is active against semi-dormant bacilli and used as a component of first-line drugs and drug-resistant tuberculosis regimens. Mutations in pncA and its promoter region are main cause of PZA resistance. There are limited PZA susceptibility data as there is no routine drug susceptibility testing (DST) for PZA. This study was aimed to determine the proportion of PZA resistance among rifampicin-resistant tuberculosis patients and to identify mutations which are responsible for PZA resistance in pncA and its promoter region. Liquid-based DST was performed to detect PZA susceptibility on 192 culture positive rifampicin-resistant isolates collected from National Tuberculosis Reference Laboratory. Sequencing on pncA including its promoter region was performed and analysis was done on 157 isolates. Phenotypic PZA resistance was detected in 58.9% of isolates. Sixty-five different mutations were distributed in pncA or promoter region of 82 isolates. Sensitivity and specificity of pncA sequencing in detection of PZA resistance showed 89.8% and 95.6% respectively. High proportion of PZA resistance among rifampicin-resistant cases highlighted the need for effective treatment regimen development for PZA-resistant MDR-TB. It is also suggested that routine PZA susceptibility test should be incorporated to treatment monitoring regimen and National Drug Resistance surveys.

Evaluation of the QuantaMatrix Multiplexed Assay Platform for Molecular Diagnosis of Multidrug- and Extensively Drug-Resistant Tuberculosis Using Clinical Strains Isolated in Myanmar.

BACKGROUND: Although the incidence of tuberculosis (TB) is decreasing, cases of multidrug-resistant (MDR) TB and extensively drug-resistant (XDR) TB continue to increase. As conventional phenotype drug susceptibility testing (pDST) takes six to eight weeks, molecular assays are widely used to determine drug resistance. we developed QuantaMatrix Multiplexed Assay Platform (QMAP) MDR/XDR assay (QuantaMatrix Inc., Seoul, Korea) that can simultaneously detect mutations related to both first- and second-line drug resistance (rifampin, isoniazid, ethambutol, fluoroquinolones, second-line injectable drugs, and streptomycin). METHODS: We used 190 clinical Mycobacterium tuberculosis (MTB) strains isolated from Myanmar, compared QMAP and pDST results, and determined concordance rates. Additionally, we performed sequence analyses for discordant results. RESULTS: QMAP results were 87.9% (167/190) concordant with pDST results. In the 23 isolates with discordant results, the QMAP and DNA sequencing results completely matched. CONCLUSIONS: The QMAP MDR/XDR assay can detect all known DNA mutations associated with drug resistance for both MDR- and XDR-MTB strains. It can be used for molecular diagnosis of MDR- and XDR-TB to rapidly initiate appropriate anti-TB drug therapy.

Genotypes and genetic characters of Mycobacterium tuberculosis from Myanmar using three typing methods.

Knowledge on basic characteristics of Mycobacterium tuberculosis (MTB) is helpful to understand the disease epidemiology and support the prediction of clinical outcome of the disease. The aim of this study was to detect the genotypes and genotypic characters of clinical Mycobacterium tuberculosis (MTB) isolates from new and retreatment rifampicin-resistant patients using three different genotyping methods. Mycobacterial interspersed repetitive units-variable number tandem repeat (MIRU-VNTR) typing was used to determine the diversity of 222 clinical isolates. Spoligotyping and IS6110-restriction fragment length polymorphism (RFLP) typing were also used to investigate the genetic characters of 105 MTB strains. Among the 15 genotypes detected by MIRU-VNTR, Beijing strains were the most prevalent of all strains (54.8%); new cases (40.5%) and retreatment cases (69.4%), followed by EAI strain. Spoligotyping categorized the strains into 11 lineages and 13 orphans whereas 96 different IS6110 patterns were identified using RFLP method. The mode number of IS6110 was 18 and 20. Higher band numbers were found in Beijing genotype (p < 0.001). Clustering rates by spoligotyping, MIRU-VNTR and IS6110-RFLP typing were 0.714, 0.004 and 0.085, respectively. Discriminatory powers of spoligotyping, MIRU-VNTR typing and IS6110-RFLP typing were 0.637, 1.000 and 0.997, respectively. Dominant Beijing genotype in both new and retreatment cases denoting that prevailing tuberculosis in Myanmar changed from EAI to Beijing lineage.

Molecular Strain Typing of Mycobacterium tuberculosis: a Review of Frequently Used Methods.

Tuberculosis, caused by the bacterium Mycobacterium tuberculosis, remains one of the most serious global health problems. Molecular typing of M. tuberculosis has been used for various epidemiologic purposes as well as for clinical management. Currently, many techniques are available to type M. tuberculosis. Choosing the most appropriate technique in accordance with the existing laboratory conditions and the specific features of the geographic region is important. Insertion sequence IS6110-based restriction fragment length polymorphism (RFLP) analysis is considered the gold standard for the molecular epidemiologic investigations of tuberculosis. However, other polymerase chain reaction-based methods such as spacer oligonucleotide typing (spoligotyping), which detects 43 spacer sequence-interspersing direct repeats (DRs) in the genomic DR region; mycobacterial interspersed repetitive units-variable number tandem repeats, (MIRU-VNTR), which determines the number and size of tandem repetitive DNA sequences; repetitive-sequence-based PCR (rep-PCR), which provides high-throughput genotypic fingerprinting of multiple Mycobacterium species; and the recently developed genome-based whole genome sequencing methods demonstrate similar discriminatory power and greater convenience. This review focuses on techniques frequently used for the molecular typing of M. tuberculosis and discusses their general aspects and applications.

Phenotypic and genotypic analysis of anti-tuberculosis drug resistance in Mycobacterium tuberculosis isolates in Myanmar.

BACKGROUND: Tuberculosis (TB) is one of the most serious health problems in Myanmar. Because TB drug resistance is associated with genetic mutation(s) relevant to responses to each drug, genotypic methods for detecting these mutations have been proposed to overcome the limitations of classic phenotypic drug susceptibility testing (DST). We explored the current estimates of drug-resistant TB and evaluated the usefulness of genotypic DST in Myanmar. METHODS: We determined the drug susceptibility of Mycobacterium tuberculosis isolated from sputum smear-positive patients with newly diagnosed pulmonary TB at two main TB centers in Myanmar during 2013 by using conventional phenotypic DST and the GenoType MTBDRplus assay (Hain Lifescience, Germany). Discrepant results were confirmed by sequencing the genes relevant to each type of resistance (rpoB for rifampicin; katG and inhA for isoniazid). RESULTS: Of 191 isolates, phenotypic DST showed that 27.7% (n=53) were resistant to at least one first-line drug and 20.9% (n=40) were resistant to two or more, including 18.3% (n=35) multidrug-resistant TB (MDR-TB) strains. Monoresistant strains accounted for 6.8% (n=13) of the samples. Genotypic assay of 189 isolates showed 17.5% (n=33) MDR-TB and 5.3% (n=10) isoniazid-monoresistant strains. Genotypic susceptibility results were 99.5% (n=188) concordant and agreed almost perfectly with phenotypic DST (kappa=0.99; 95% confidence interval 0.96-1.01). CONCLUSIONS: The results highlight the burden of TB drug resistance and prove the usefulness of the genotypic DST in Myanmar.

Sexually transmitted infections among male highway coach drivers in Myanmar.

A cross sectional descriptive study was conducted from February 2008 to December 2009 at the largest Highway Terminal, Yangon, Myanmar to determine the prevalence of curable STIs (syphilis, gonorrhea, chlamydial infections, and trichomoniasis), to find out the associated factors for STIs, and to determine the antibiotic susceptibility pattern of gonococcal infection among highway drivers. Urine and blood specimens were collected from 601 male highway coach drivers after an interview about their behavior. Standard laboratory tests were carried out to detect STIs. Multivariate analysis was used to ascertain potential risk factors for STIs. The prevalence rates of syphilis, gonorrhea, chlamydial infections, and trichomoniasis were 4.8, 4.3, 5.7, and 9.8%, respectively. One hundred and two (17.0%) were infected with at least one of the tested four STIs, and 34 (5.7%) had STI co-infections (2STIs). Those who had multiple sexual contacts were likely to be infected with at least one STI, and those who had a history of inconsistent condom use within past two weeks and multiple sexual contacts were more likely to have STI co-infections (p < 0.05). Antimicrobial susceptibility of 21 Neisseria gonorrhoeae isolates showed that 85.7% were susceptible to azithromycin, 80.9% to spectinomycin, 66.7% to cefixime, 61.9% to ceftriaxone, and 38.1% to ciprofloxacin. The high prevalence of STIs in this study and the decreased susceptibility of Neisseria gonorrhoeae to cephalosporin and fluoroquinolone highlighted the role of periodic screening in early diagnosis and effective treatment of STIs among high-risk populations.