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ObjectiveTo determine the distribution of various antibiotic resistance genes （ARGs） in raw water from drinking water source， and to explore the correlation between the ARGs and common carbapenem-resistant and multidrug-resistant bacteria isolated from drinking water source， so as to provide scientific evidence for improving the safety of urban drinking water. MethodsA total of 30 raw water samples were collected from a major drinking water source in Shanghai in 2020. Bacterial strains were selectively cultured on Columbia blood agar medium containing 1 μg·μL-1 meropenem， and then identified by MALDI-TOF-MS mass spectrometry system. Minimum inhibitory concentration （MIC） of the strains was detected by broth microdilution method. The water samples were filtered through a 0.45 μm filter membrane and diversity of ARGs was determined by using high-throughput metagenomic sequencing. ResultsA total of 64 strains of carbapenem-resistant bacteria were isolated from the water samples， including Stenotrophomonas maltophilia， Enterococcus faecium， Pseudomonas aeruginosa， Acinetobacter baumannii and Klebsiella pneumoniae， which were resistant to a variety of common antibiotics. Using metagenomic sequencing，1 244 ARGs were identified. The relative average abundance of the top 100 ARGs accounted for 96.1%， and that of the multidrug-resistant ARGs accounted for 63.41%. Furthermore， the multidrug-resistant ARGs were mainly adeJ， mexT， adeC， oprM， mexF， mdfA， mexB， mdtK， adeK， etc. Using Spearman's correlation， five multidrug-resistant bacteria isolated from the drinking water source were significantly associated with the ARGs. ConclusionRelative abundance of multidrug-resistant ARGs is high in raw water from main drinking water source. The five isolated carbapenem-resistant and multidrug-resistant bacteria are significantly correlated with the ARGs. It warrants strengthening the rational and standardized application of antibiotics to protect water resources and ensure the safety of drinking water.
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9 adults aged 23 to 43 years old were treated with bidimensional self-ligating lingual bracket technique for upper teeth and labial ceramic or aesthetic bracket for lower teeth.After treatment the labioclination of anterior teeth in Angle's II patients decreased from 28.12°± 10.05°to 19.25°±3.12°(P <0.05),in Angle's III patients from 32.14°±4.71°to 28.15°±3.26(P <0.05).
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Objective: To investigate the effects and mechanism of microscrew implant anchorage (MIA) in speeding up the closure of extraction space by one step and retraction of anterior teeth. Methods: Twenty-three patients with teeth extraction and required strong posterior anchorage were treated with MIA to close the extraction space. The extraction spaces were closed by two methods respectively. The extraction spaces were closed by the method of one step and retraction of anterior teeth(Ni-Ti spring from MIA to the hook on the wire combined with the elastic pull from MIA to cuspid) on the experiment sides and by the traditional one step method(Ni-Ti spring from MIA to the hook on the wire alone) on the control sides. Which side treated as trial side or control side was selected at random. The period of the space closing, the way and position of anterior teeth movement were observed on each side and the period of the space closing of two sides were tested by paired t test. Results: ①The average period of the spaces closing which was (6.69±1.07) months on the trial side and (9.56±1.19) months on the control side was significantly different (P<0.05).② After the closure of extraction spaces, the cuspid achived better position on the trial side than the contral side on which cuspid presented distal-lingual rotation. Conclusion: The extraction spaces can be closed in all cases by two methods respectively. Using MIA to close the extraction space by one step and retraction of anterior teeth can not only shorten the period of space closing but also achieve nice outcome by moving the cuspid in spongy bone.
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Objective:To analyze the characteristics and differences of upper airway forms in the adults with class Ⅱ sagittal facial type of different vertical facial types and investigate the correlation between craniofacial structures and upper airway forms.Methods:Cephalograms of 135 adults with classⅡsagittal facial type of different vertical facial types were collected.60 cases were males and 75 cases were females.All the cephalograms were measured in sagittal upper airway depths.The differences were compared between genders,and also among different vertical facial type groups.Results:Among different vertical facial type groups,only the sagittal depths of nasopharynx(PNS-Ba、PNS-R)of the males and PNS-Ba of the females in high angle groups were smaller than that in average and low angle groups(P0.05),but the values of V-LPW of the males were larger than that of the famales in all vertical facial type groups(P
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Objective: To compare and analyze the maxillary lingual arch forms of ClassⅠmalocclusions after extraction and non-extraction treatment respectively. Methods: 60(30 with extraction, 30 non-extraction)maxillary dental models of ClassⅠmalocclusions after orthodontic treatment were measured in lingual arch widths and depths. The data were analyzed by statistical methods and the charts of lingual arch forms were drawn. Results: The lingual arch widths and depths in anterior segments of the extraction group were significantly larger than those of the non-extraction group(P0.05). The lingual arch forms of the two groups were similar in anterior segments, and more different in premolar and first molar segments, but similar from the distal lingual cusp of the first molars. Conclusion: The lingual arch forms of the two groups are similar in appearances, but the anterior segments of the extraction group are deeper than that of the non-extraction group.