Clinical and Imaging Characteristics of Primary Severe Community-Acquired Pneumonia Caused by Hypervirulent Klebsiella Pneumoniae.

BACKGROUND: To investigate the CT imaging features and microbial phenotypes of primary severe community-acquired pneumonia caused by hypervirulent Klebsiella pneumoniae (hvKp). METHODS: Patients diagnosed with primary hvKp pneumonia were included, and their clinical data were analyzed, including the baseline characteristics and CT imaging results. After hypermucoviscosity phenotyping, the strains, serological types, and virulence genes of hvKp were identified using multiplex PCR. RESULTS: Twelve patients with primary hvKp pneumonia were included (11 males, 1 female). All patients were infected via respiratory tract inhalation. Ten patients were long-term drinkers. Four patients (33.3%), who were long-term alcohol abusers, died within 30 days after diagnosis. No extrapulmonary metastatic infection was found in any patient. The imaging of lung lesions at the early disease stage exhibited an extensive consolidation in the lungs. As the disease progressed, the most common imaging features were pleural effusion (9/12), cavitation and necrosis (8/12), and pneumothorax (3/12). The serological typing of the capsular polysaccharides on hvKp strains were K1 (6/12) and K2 (6/12). Furthermore, the virulence genotyping showed rmpA (11/12), magA (11/12), ureA (12/12), mrkD (12/12), fim-1 (12/12), wabG (12/12), ybtS (12/12), and iucB (11/12). CONCLUSIONS: Primary severe community-acquired hvKp-associated pneumonia is more common in men, especially those with a long-term history of alcohol consumption. CT scanning at the early disease stage mostly showed extensive pulmonary consolidation, which was prone to be combined with cavitation, necrosis, and pleural effusion. K1 and K2 serotypes were identified among the hvKp strains, which were not prone to form extrapulmonary metastasis via the bloodstream.

[A study of frictional resistance of archwires and ligating methods].

PURPOSE: To study the effect of 4 archwires and 2 ligating methods on the frictional resistance. METHODS: The static and dynamic friction of different combinations of 4 archwires and 6 preadjusted brackets and 2 ligating methods in the buccal segments were tested in the dry state. The friction was tested by the load cell in the LJ-500 testing machine. Orthogonal experiment design was performed in this study. The data were analysed by analysis of variance and regression analysis using the statistical analysis system. RESULTS: The smallest frictional resistance in 4 different archwires was produced by combination of 0.018 x 0.025 inch stainless rectangular wire and all preadjusted brackets. The biggest frictional resistance in 4 different archwires was produced by combination of 0.019 x 0.025 inch stainless rectangular wire and all preadjusted brackets. The static friction of combination of 0.020 inch stainless round wire and all preadjusted brackets were higher than 0.018 inch stainless round wire. The dynamic friction of combination of 0.018 inch stainless round wire and all preadjusted brackets were higher than 0.020 inch stainless round wire. Among 4 kinds of stainless wires, the ratio of dynamic to static friction of 0.018 inch round wire appeared the highest, followed by 0.018 x 0.025 inch rectangular wire, 0.020 inch round wire and 0.019 x 0.025 inch rectangular wire. Elastomeric ring ligature produced higher friction and the ratio of dynamic to static friction than stainless steel ligature. CONCLUSIONS: 0.018 inch stainless steel round wire was not suitable for sliding mechanics in this study. One should pay attention to anchorage control in using 0.019 x 0.025 inch rectangular wire. Elastomeric ring ligature was not advantageous for sliding of brackets and wires in the dry state.