Objective:To analyze the carriage status, subtype distribution and flanking gene sequence characteristics of oxacillinases (OXA enzyme) in 241 clinical strains of Pseudomonas aeruginosa, and assess their roles in the drug resistance of Pseudomonas aeruginosa and ability to horizontally transfer across species. Methods:Clinical P. aeruginosa isolates were collected from four hospitals in Sanya, Tangshan, Zhangjiakou, and Beijing. The prevalence of oxacillinases and their flanking gene sequences was analyzed by whole-genome sequencing (NGS) and bioinformatic approaches. Results:A total of 241 isolates of P. aeruginosa were gathered, and 35 blaOXA subtypes were identified through screening of 252 blaOXA genes. These genes were classified into three subfamilies: blaOXA-50-like (241, 95.6%), blaOXA-1-like (9, 3.6%) and blaOXA-10-like (2, 0.8%). Among these, 11 subtypes (11, 31.4%) were novel blaOXA subtypes. Nine of these belonged to the blaOXA-50-like subfamily and were designated as blaOXA-1244, blaOXA-1245, blaOXA-1246, blaOXA-1250, blaOXA-1252, blaOXA-1253, blaOXA-1254, blaOXA-1255, and blaOXA-1256. The remaining two belonged to the blaOXA-10-like subfamily and were named blaOXA-1247 and blaOXA-1248. Compared to the amino acid sequence of OXA-10, the newly identified subtype OXA-1247 exhibited a mutation at position 117, where a valine was replaced by a leucine. This change was thought to improve the enzyme′s ability to hydrolyze carbapenems. In the analysis of the flanking sequences of the blaOXA genes, Class I integrons were identified in four bacterial strains. The variable regions of these integrons carried three distinct patterns of resistance gene cassettes: aac( 6′) -Ib-blaOXA-1247-ant( 3′′) -Ia, aac( 6′) -Ib-blaOXA-1248 and aac( 6′) -Ib- blaIMP-45-blaOXA-1-catB3. Among these, the strain BJ2326 carried a class I integron that was connected to the downstream IS CR1 element to form a composite class I integron structure, additionally carrying the resistance gene blaPER-1. Out of the 223 non-wild-type P. aeruginosa strains, 127 strains exhibited non-wild-type profiles to the four beta-lactam antibiotics MEM, CAZ, FEP, and TZP, with the combination of MEM+CAZ+FEP being the most prevalent, representing 57.0% of the total. Conclusions:The blaOXA genes in 241 clinical P. aeruginosa strains showed diversity. Some blaOXA genes had a co-transfer risk with the metallo-β-lactamase resistance gene blaIMP-45. Among the 11 newly discovered blaOXA subtypes, the new subtype OXA-1247 may have carbapenemase activity and potential for horizontal transfer.

Objective:To analyze the carriage status, subtype distribution and flanking gene sequence characteristics of oxacillinases (OXA enzyme) in 241 clinical strains of Pseudomonas aeruginosa, and assess their roles in the drug resistance of Pseudomonas aeruginosa and ability to horizontally transfer across species. Methods:Clinical P. aeruginosa isolates were collected from four hospitals in Sanya, Tangshan, Zhangjiakou, and Beijing. The prevalence of oxacillinases and their flanking gene sequences was analyzed by whole-genome sequencing (NGS) and bioinformatic approaches. Results:A total of 241 isolates of P. aeruginosa were gathered, and 35 blaOXA subtypes were identified through screening of 252 blaOXA genes. These genes were classified into three subfamilies: blaOXA-50-like (241, 95.6%), blaOXA-1-like (9, 3.6%) and blaOXA-10-like (2, 0.8%). Among these, 11 subtypes (11, 31.4%) were novel blaOXA subtypes. Nine of these belonged to the blaOXA-50-like subfamily and were designated as blaOXA-1244, blaOXA-1245, blaOXA-1246, blaOXA-1250, blaOXA-1252, blaOXA-1253, blaOXA-1254, blaOXA-1255, and blaOXA-1256. The remaining two belonged to the blaOXA-10-like subfamily and were named blaOXA-1247 and blaOXA-1248. Compared to the amino acid sequence of OXA-10, the newly identified subtype OXA-1247 exhibited a mutation at position 117, where a valine was replaced by a leucine. This change was thought to improve the enzyme′s ability to hydrolyze carbapenems. In the analysis of the flanking sequences of the blaOXA genes, Class I integrons were identified in four bacterial strains. The variable regions of these integrons carried three distinct patterns of resistance gene cassettes: aac( 6′) -Ib-blaOXA-1247-ant( 3′′) -Ia, aac( 6′) -Ib-blaOXA-1248 and aac( 6′) -Ib- blaIMP-45-blaOXA-1-catB3. Among these, the strain BJ2326 carried a class I integron that was connected to the downstream IS CR1 element to form a composite class I integron structure, additionally carrying the resistance gene blaPER-1. Out of the 223 non-wild-type P. aeruginosa strains, 127 strains exhibited non-wild-type profiles to the four beta-lactam antibiotics MEM, CAZ, FEP, and TZP, with the combination of MEM+CAZ+FEP being the most prevalent, representing 57.0% of the total. Conclusions:The blaOXA genes in 241 clinical P. aeruginosa strains showed diversity. Some blaOXA genes had a co-transfer risk with the metallo-β-lactamase resistance gene blaIMP-45. Among the 11 newly discovered blaOXA subtypes, the new subtype OXA-1247 may have carbapenemase activity and potential for horizontal transfer.

An efficient vacuum suction system is a necessary prerequisite for the smooth operation of the oral diagnosis and treatment.During the use of the dental units,there is often a situation of vacuum suction weakness,resulting in the inability to discharge the mixture of blood,saliva,dental tissue and other mixtures in time,which affects the doctor's treatment field and increases the risk of aspiration pneumonia and cross-infection in patients.The working principle,pipeline system,filters and other aspects of the vacuum suction system that may affect the suction efficiency was analyzed.The causes and solutions of vacuum suction weakness were discussed,and operation suggestions were proposed to ensure the safe and effective use of equipment and ensure the safety of diagnosis and treatment.

Objective? To compare the effect of European Nutritional Risk Screening (NRS 2002) and Patient General Subjective Score (PG-SGA) in perioperative patients with head and neck squamous cell carcinoma, and to provide evidence for clinical nutritional screening in perioperative patients with head and neck squamous cell carcinoma. Methods? Using convenience sampling method, 82 patients with head and neck squamous cell carcinoma who were admitted to the Department of Head and Neck Surgery of Zhejiang Cancer Hospital from October 2015 to December 2017 during perioperative period were selected as the study subjects. NRS 2002 and PG-SGA were used to longitudinally evaluate their nutritional status at admission, 1 day before operation, 2 days after operation, 1 week after operation and at discharge, respectively. The differences of nutritional status between the two assessment tools during perioperative period were compared. Results? The trend of malnutrition risk in NRS 2002 was similar to that in PG-SAG dynamic assessment from admission to discharge, all of which were in the form of "V". The positive rate of malnutrition in PG-SAG assessment was higher than that in NRS 2002, and the difference was statistically significant (P＜ 0.01). Conclusions? NRS 2002 and PG-SGA are both suitable for nutritional risk screening of head and neck squamous cell carcinoma patients, but the positive rate of PG-SGA is higher, which can effectively screen and evaluate the nutritional status of head and neck squamous cell carcinoma patients, and is conducive to timely providing nutritional intervention and treatment for patients.

Objective To comprehensively evaluate the clinical efficacy of hemoperfusion (HP) combined with continuous veno-venous hemofiltration (CVVH) on acute paraquat poisoning (APP).Methods Literatures of Chinese and English randomized controlled trials (RCTs), case control and cohort study on HP combined with CVVH in the treatment of APP from the PubMed, Embase, Wanfang, and CNKI up to November 2017 were enrolled (the subjects were > 16 years old). The obtained literatures were strictly screened and evaluated in quality, and data such as mortality, the life time of dead patients, inefficiency rate, incidence of multiple organ dysfunction syndrome (MODS) and acute respiratory distress syndrome (ARDS) were extracted. Meta-analysis was performed by RevMan 5.3. Results Twenty-one studies were included with 2222 subjects, among whom 976 subjects were in HP combined with CVVH group (experimental group) and 1246 subjects in HP group (control group). Compared with control group, the mortality in experimental group were significantly decreased [43.77％ (362/827) vs. 55.26％ (604/1093), odds ratio (OR) =0.68, 95％ confidential interval (95％CI) = 0.56-0.82,P = 0.0001], the life time of death patients was significantly prolonged [mean difference (MD) = 4.63, 95％CI = 2.60-6.66,P < 0.00001], incidence of MODS [25.93％ (70/270) vs. 55.36％ (155/280),OR = 0.26, 95％CI = 0.14-0.49,P< 0.0001], and incidence of ARDS [30.37％ (82/270) vs. 51.07％(143/280),OR = 0.42, 95％CI = 0.30-0.61,P < 0.00001], and inefficiency rate [8.72％ (13/149) vs. 34.64％ (53/153),OR=0.17, 95％CI = 0.09-0.34, P < 0.00001] were significantly reduced. Funnel chart showed that except the publication bias of mortality rate, there were less publication bias about other indicators among studies.Conclusion HP combined with CVVH can significantly reduce the mortality of patients with APP compared with HP alone on the whole, prolong the life time and reduce the occurrence of MODS and ARDS, thus improving the treatment efficiency.