Transmission and drug-resistance of tuberculosis in Luodian revealed by whole genome sequencing based molecular epidemiology study

BACKGROUND Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB), remains a severe public health problem globally. Guizhou has the fourth highest TB report rate of pulmonary TB around China. Uncovering the current status of TB epidemic, and distinguishing disease caused by recent or remote infections are the key issue to formulate effective prevention and control strategy. However, these data are limited in Guizhou. In this study, we aimed to investigate the transmission and drug-resistance profiles of TB in Luodian, a highest TB incidence and resources limited area in Guizhou, China. METHODS During 22 May 2018 to 21 April 2019, individuals with positive MTB culture were enrolled, all of them accepted the standardized interview. MTB isolates were performed whole genome sequencing. The prevalence of MTB genotypes, the genomic cluster rate and drug-resistance conferring mutations were analyzed based on the sequencing data. RESULTS A total of 107 cases were enrolled, of which 64.5% were male, and the median age of the patients was 51 years old (interquartile range, 40–65 years old). 84% patient were new case while 16% were retreated cases. All cases excepted three came from nine towns, and 55.1% of cases were from Longping and Bianyang. The phylogeny tree showed that 53.3% of strains were Lineage 2 (Beijing genotype), while 46.7% were Lineage 4 (Euro-American genotype). Among Lineage 2 strains, 66.7% were modern Beijing. Seven clusters with genomic distance within 12 SNVs were identified. The clusters included 14 strains, accounting for a cluster rate of 13.1%. The distance of clustered cases was between 2.1 to 71 kilometers (Km), with a media distance of 14 Km (interquartile range, 2.8–38 Km). Cases of two clusters came from the same town. Based on the gene mutations associated to drug-resistance, we predicted that 4.8% was resistant to isoniazid, 3.7% to rifampicin, 3.7% to streptomycin, and only one strain (0.9%) was multidrug resistance (MDR). CONLUSIONS: The study found high transmission and low drug-resistance rate in Luodian, and sublineages of modern Beijing branch had recent expansion in Luodian. this work also may serve as a genomic baseline to study the evolution and spread of MTB in Guizhou.

Thinning and Diametric Fruit Growth Response of Apple Trees Treated with Benzyladenine and GA4+7 (Accel®), Carbaryl, and NAA

A series of seven fruit thinning experiments with benzyladenine (BA), benzyladenine and GA4+7 (10:1 BA:GA4+7, Accel), carbaryl (CB), and NAA were conducted at the Horticultural Experiment Station, Simcoe, during the 1993 and 1994 growing seasons. In 1993, BA and Accel at 0, 100, 200, and 300 mg of BA/liter were applied to mature `Redspur Delicious'/M.26 and `Empire'/M.26 trees when fruit were ≈10 mm in diameter. In one set of experiments in 1994, Accel was applied at 0, 25, 50, 100, 150, and 200 mg of BA/liter to mature `McIntosh'/M.26 and `Empire'/M.7 trees. In a second set of experiments in 1994, Accel was applied at 0, 50, and 100 mg of BA/liter to mature `Idared'/M.26, `Empire'/M.26, and `Marshall McIntosh'/Mark trees when fruit were ≈10 mm in diameter. Additional treatments included bloom sprays of Accel at 50 mg of BA/liter, and sprays of BA at 50 mg a.i/liter, NAA at 10 mg a.i./liter, CB at 1000 mg a.i./liter, and a “low” (two fruit remaining/flower cluster) and `”high” (one fruit remaining/flower cluster) rate of hand thinning. In all experiments, thinning response to BA and Accel increased with concentration. Concentrations below 50, 100, and 300 mg BA/liter were generally ineffective for thinning `Empire', `Idared', and `McIntosh', and `Delicious', respectively. Fruit size of `Idared' and `Empire' was increased at rates of 50 mg BA/liter, whereas rates of 100 mg BA/liter were needed to increase fruit size of `McIntosh'. Accel applied to `Empire' at 150 mg BA/liter decreased the number of seeds per fruit and increased fruit length:diameter (L:D) ratios. Concentrations of Accel exceeding 100 mg BA/liter in `Red Delicious' decreased the number of seeds per fruit, while having little effect on fruit L:D ratios even though lower concentrations increased fruit L:D ratios. Diametric fruit growth measurements in 1994 indicated a temporary, but sharp, decline in growth rate immediately following treatment imposition for trees that responded positively to thinning. Additional data describing treatment effects on fruit size distribution, vegetative growth, and fruit maturity will be presented and discussed in relation to crop load.