1.Differences in deltamethrin resistance and kdr gene mutation in Culex tritaeniorhynchus population in and outside the Yellow Sea wetland
Xiao-er ZHANG ; Zhi-ming WU ; Ye TIAN ; Qian CUI ; Yu-qian JI ; Huan WANG ; Shu-juan YANG ; Yi-chao ZHAO ; Yu WANG ; Hua-yu YIN ; Yu DING ; Guo-jin YAN ; Min-sen ZHAO ; Shou-gang ZHANG ; Bing-dong SONG ; Hong-na CHEN ; Jian GAO ; Wei-fang YANG ; Yu-fu ZHANG ; Hui LIU ; Hong-liang CHU
Acta Parasitologica et Medica Entomologica Sinica 2026;33(2):101-107
Objective To gain insights into the biological characteristics of different populations of Culex tritaeniorhynchus within and around the Yellow Sea wetland from the perspective of the occurrence of resistance, we investigated the levels of resistance to deltamethrin and kdr gene mutation in the wetland and its peripheral areas. Methods Specimens were collected from Cx. tritaeniorhynchus populations at two monitoring sites in the Rare Bird National Nature Reserve and Tiaozi Ni Wetland Scenic Area, and also from two populations in Yancheng City and the Liuhe District of Nanjing, and the resistance of these mosquitoes to deltamethrin was determined using the CDC biotest bottle method. For each concentration of deltamethrin assessed, a random subset of exposed specimens was selected for amplification of the kdr gene fragment, followed by Sanger sequencing to identify and analyze resistance-associated mutations. Results The LC50 levels of deltamethrin among mosquitoes from the four populations in Luhe, Yancheng, the Rare Bird National Nature Reserve and the Tiaozi Ni Wetland Scenic Area were 2.048 5, 7.798 2, 3.473 3, and 17.695 5 mg/mL, respectively, with corresponding concentrations of deltamethrin ranging from 0.005 to 5.000,0.050 to 50.000,0.050 to 25.000 and 0.050 to 50.000 mg/mL, respectively. Furthermore, the ranges of the KT50 values were 11.76-107.43, 67.05-216.30,29.77-107.43 and 28.40-329.51 min; the 1-h knockdown rates were 34.58%-99.15%, 9.52%-43.80%, 55.09%-73.01%, and 10.09%-68.07%; and the 24-h mortality rates were 12.15%-67.52%,9.52%-79.56%,13.17%-82.21%, and 11.01%-78.99%, respectively. With respect to kdr gene mutation, we assayed a total of 63,70,59, and 57 mosquitoes for the four populations, for which we detected L1014F mutation frequencies of 14.29%, 35.00%, 20.34%, and 31.58%, respectively, with a majority of these mutations being heterozygous for resistance. In addition, five adult mosquitoes were identified has having synonymous mutations at site 1011[i. e. , AAT(asparagine)mutation to AAC(asparagine)]. Conclusions Our findings revealed the clear resistance of Cx. tritaeniorhynchus to deltamethrin in the Yancheng region of the Yellow Sea wetland, and the resistance phenotype and kdr frequency of Cx. tritaeniorhynchus in the wetland environment were comparable to those of Cx. tritaeniorhynchus in the wetland environment, thereby indicating that the resistance of different populations of Cx. tritaeniorhynchus was homogeneous under the pressure of different insecticide selection within and around the wetland. However, the underlying mechanisms need to be further studied.
2.Risk factors associated with hemodynamic instability in carotid artery stenting:a systematic review and meta-analysis
La-ting ZHANG ; Xiao-qing WANG ; Lin HAN ; Xin-hui LIANG ; Yao JIA ; Li-juan GAO ; Xue JIANG
Chinese Journal of Interventional Cardiology 2025;33(4):201-214
Objective To investigate the risk factors of hemodynamic instability after carotid artery stenting by meta-analysis.Methods Ten databases were searched:PubMed,ProQuest,ScienceDirect,Embase,Cochrane Library,Web of Science,China Knowledge Network,Wanfang Data,VIP Information Database,and China Biomedical Database.The search date was from inception until 2 February 2024,and meta-analysis was performed using Stata 16.0 statistical software.Results A total of 27 studies with 4199 subjects and 22 influencing factors were included.The studies showed a 37.4%(95%CI 30.3%-44.8%)incidence of haemodynamic instability after carotid stenting,Meta-analysis determined that age>60 years(P<0.001),hypertension(P<0.001),calcified plaque(P<0.001),stenosis>70%(P=0.008),eccentric plaque(P=0.002),distance from the largest stenosis to the carotid bifurcation≤ 10 mm(P<0.001),stenosis involvement of the balloon or bifurcation(P<0.001),balloon post-dilation(P=0.003),open-loop stenting(P<0.001),dilated balloon diameter≥5 mm(P=0.002),repeat balloon dilation(P=0.011)and balloon dilation pressure≥8 atm(P<0.001)are risk factors for intraoperative and postoperative haemodynamic instability in patients undergoing carotid artery stenting surgery.Statin use was a protective factor(P<0.001).Conclusions Medical staff working in the clinic should assess the patient's condition preoperatively,identify risk factors that may lead to haemodynamic instability,and avoid unnecessary intraoperative stimulation of patients who are already in a high-risk state.Reduce postoperative clinical complications in patients with carotid artery stenosis and improve patient recovery.
3.Chemical constituents from the petroleum ether fraction of the roots of Gypsophila licentiana
Zhi-ning GAO ; Tian-tian QIU ; Tian-yi CUI ; Xiao-ya SUN ; Shu-juan XUE ; Sui-qing CHEN
Chinese Traditional Patent Medicine 2025;47(3):821-827
AIM To study the chemical constituents from the petroleum ether fraction of the roots of Gypsophila licentiana Hand.-Mazz.METHODS Silica gel,Sephadex LH-20 and semi-preparative HPLC were used for isolation and purification,then the structures of obtained compounds were identified by physicochemical properties and spectral data.RESULTS Eighteen compounds were isolated and identified as dibutyl phthalate(1),glyceryl arachidate(2),bis(2-ethylhexyl)terephthalate(3),9,12-octadecadienoic acid(Z,Z)-methyl ester(4),(3'S,4'S)-3'-acetoxy-4'-angeloyloxy-3',4'-dihydroseselin(5),3-(4-hydroxy-3-methoxyphenyl)-propanoic acid(6),bis(2-ethylhexyl)phthalate(7),2,2'-oxybis(1,4)-di-tert-butylbenzene(8),gypsogenin(9),3-keto,16α-hydroxy,24-noroleanolic acid(10),3-oxo-olean-12-en-28-oic acid(11),10-eicosenoic acid(12),hexacosanic acid(13),enniatin B(14),(R,Z)-21-methyl-8-pentatriacontene(15),ethyl gallate(16),stellarine A(17),pentacosane(18).CONCLUSION All compounds are isolated from this plant for the first time.
4.Antimicrobial resistance surveillance in the bacterial strains isolated from pediatric intensive care units in China:results from 2020 to 2022
Jing LIU ; Huiyuan YAN ; Gangfeng YAN ; Guoping LU ; Pan FU ; Chuanqing WANG ; Danqun JIN ; Wenjia TONG ; Chenyu ZHANG ; Jianli CHEN ; Yi LIN ; Jia LEI ; Yibing CHENG ; Qunqun ZHANG ; Kaijie GAO ; Yuanyuan CHEN ; Shufang XIAO ; Juan HE ; Li JIANG ; Huimin XU ; Yuxia LI ; Hanghai DING ; Hehe CHEN ; Yao ZHENG ; Qunying CHEN ; Ying WANG ; Hong REN ; Chenmei ZHANG ; Zhenjie CHEN ; Mingming ZHOU ; Yucai ZHANG ; Yiping ZHOU ; Zhenjiang BAI ; Saihu HUANG ; Lili HUANG ; Weiguo YANG ; Weike MA ; Qing MENG ; Pengwei ZHU ; Yong LI ; Yan XU ; Yi WANG ; Yanqiang DU ; Huijun CAI ; Bizhen ZHU ; Huixuan SHI ; Shaoxian HONG ; Yukun HUANG ; Meilian HUANG
Chinese Journal of Infection and Chemotherapy 2025;25(3):303-311
Objective This study aimed to investigate the antimicrobial resistance profiles of bacterial strains isolated from pediatric intensive care units(PICU)in China for better antimicrobial therapy.Methods Clinical isolates were collected from 17 institutions,including tertiary care children's hospitals and pediatric department of tertiary general hospitals in China from January 1,2020 to December 31,2022.Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems.Results were interpreted according to the breakpoints released by the Clinical and Laboratory Standards Institute(CLSI)in 2020.Results A total of 10 688 isolates were collected,including gram-positive organisms(39.2%)and gram-negative organisms(60.8%).The top three organisms were S.aureus(13.6%,1 453/10 688),A.baumannii(10.0%,1 067/10 688),and coagulase-negative Staphylococcus(9.9%,1 058/10 688).Multi-drug resistant organisms(MDROs)were very common in children.The prevalence of methicillin-resistant Staphylococcus aureus(MRSA),carbapenem-resistant Enterobacterales(CRE),carbapenem-resistant E.coli,carbapenem-resistant K.pneumoniae(CRKP),carbapenem-resistant A.baumannii(CRAB),and carbapenem-resistant P.aeruginosa(CRPA)was 41.1%,19.4%,8.8%,30.9%,67.4%,and 28.8%,respectively.Overall,more than 50%of Enterobacteriales isolates were resistant to cephalosporins,while nearly 25%of Enterobacteriales isolates were resistant to carbapenems.MDROs were highly resistant to commonly used antibiotics.More than 80%of CRE and CRAB strains were resistant to all beta-lactam antibiotics.CRE and CRAB showed low resistance rates to tigecycline and polymyxin.CRPA showed lower resistance rates to piperacillin,beta-lactamase inhibitor combinations than the resistance rates to third and fourth generation cephalosporins.All of the Staphylococcus and Enterococcus isolates were susceptible to vancomycin and tigecycline.None of PRSP strains isolated from meningitis and nonmeningitis samples were resistant to rifampicin,vancomycin,or linezolid.The prevalence of β-lactamase-negative ampicillin-resistant(BLNAR)strains was 43.3%in Haemophilus influenzae.Conclusions MDROs were prevalent in PICU.It is necessary to establish an effective multidisciplinary team(MDT)to control the antimicrobial resistance.
5.Antimicrobial resistance surveillance in the bacterial strains isolated from pediatric intensive care units in China:results from 2020 to 2022
Jing LIU ; Huiyuan YAN ; Gangfeng YAN ; Guoping LU ; Pan FU ; Chuanqing WANG ; Danqun JIN ; Wenjia TONG ; Chenyu ZHANG ; Jianli CHEN ; Yi LIN ; Jia LEI ; Yibing CHENG ; Qunqun ZHANG ; Kaijie GAO ; Yuanyuan CHEN ; Shufang XIAO ; Juan HE ; Li JIANG ; Huimin XU ; Yuxia LI ; Hanghai DING ; Hehe CHEN ; Yao ZHENG ; Qunying CHEN ; Ying WANG ; Hong REN ; Chenmei ZHANG ; Zhenjie CHEN ; Mingming ZHOU ; Yucai ZHANG ; Yiping ZHOU ; Zhenjiang BAI ; Saihu HUANG ; Lili HUANG ; Weiguo YANG ; Weike MA ; Qing MENG ; Pengwei ZHU ; Yong LI ; Yan XU ; Yi WANG ; Yanqiang DU ; Huijun CAI ; Bizhen ZHU ; Huixuan SHI ; Shaoxian HONG ; Yukun HUANG ; Meilian HUANG
Chinese Journal of Infection and Chemotherapy 2025;25(3):303-311
Objective This study aimed to investigate the antimicrobial resistance profiles of bacterial strains isolated from pediatric intensive care units(PICU)in China for better antimicrobial therapy.Methods Clinical isolates were collected from 17 institutions,including tertiary care children's hospitals and pediatric department of tertiary general hospitals in China from January 1,2020 to December 31,2022.Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems.Results were interpreted according to the breakpoints released by the Clinical and Laboratory Standards Institute(CLSI)in 2020.Results A total of 10 688 isolates were collected,including gram-positive organisms(39.2%)and gram-negative organisms(60.8%).The top three organisms were S.aureus(13.6%,1 453/10 688),A.baumannii(10.0%,1 067/10 688),and coagulase-negative Staphylococcus(9.9%,1 058/10 688).Multi-drug resistant organisms(MDROs)were very common in children.The prevalence of methicillin-resistant Staphylococcus aureus(MRSA),carbapenem-resistant Enterobacterales(CRE),carbapenem-resistant E.coli,carbapenem-resistant K.pneumoniae(CRKP),carbapenem-resistant A.baumannii(CRAB),and carbapenem-resistant P.aeruginosa(CRPA)was 41.1%,19.4%,8.8%,30.9%,67.4%,and 28.8%,respectively.Overall,more than 50%of Enterobacteriales isolates were resistant to cephalosporins,while nearly 25%of Enterobacteriales isolates were resistant to carbapenems.MDROs were highly resistant to commonly used antibiotics.More than 80%of CRE and CRAB strains were resistant to all beta-lactam antibiotics.CRE and CRAB showed low resistance rates to tigecycline and polymyxin.CRPA showed lower resistance rates to piperacillin,beta-lactamase inhibitor combinations than the resistance rates to third and fourth generation cephalosporins.All of the Staphylococcus and Enterococcus isolates were susceptible to vancomycin and tigecycline.None of PRSP strains isolated from meningitis and nonmeningitis samples were resistant to rifampicin,vancomycin,or linezolid.The prevalence of β-lactamase-negative ampicillin-resistant(BLNAR)strains was 43.3%in Haemophilus influenzae.Conclusions MDROs were prevalent in PICU.It is necessary to establish an effective multidisciplinary team(MDT)to control the antimicrobial resistance.
6.Comparison of in vitro anti-precancerous lesions of gastric cancer activities of different polar extracts from Bombyx batryticatus
Miao-miao CHANG ; Xiao-hong ZHOU ; Bo-wen LI ; Wei-juan GAO
Chinese Pharmacological Bulletin 2025;41(12):2282-2290
Aim To compare the differences in the in vitro anti-precancerous lesions of gastric cancer(PL-GC)activities of different polar extracts from Bombyx batryticatus.Methods Bombyx batryticatus was ex-tracted by ethanol reflux,and the extract was further partitioned using different polarity organic solvents to obtain four fractions:petroleum ether(SYM),ethyl acetate(YSYZ),n-butanol(ZDC),and aqueous phase(SX).The PLGC cell model was established by inducing malignant transformation in GES-1 cells using N-methyl-N-nitro-N-nitrosoguanidine(MNNG).The optimal concentration of four extracts were determined by CCK-8 assay.The proliferation,migration and in-vasion of cells in each group were detected by plate cloning,scratch healing and Transwell assay,respec-tively.The expression levels of E-cadherin,Vimentin and key proteins of the PI3 K/AKT/mTOR signaling pathway in cells of each group were detected by West-ern blot.Meanwhile,chemical components of the four extracts were analyzed by UPLC-Q-TOF-MS/MS.Re-sults Compared with the normal group,the prolifera-tion,migration and invasion abilities of cells in the PL-GC group were significantly enhanced,the expression levels of E-cadherin proteins of PLGC cells were down-regulated,and the expression levels of Vimentin,p-PI3K,p-AKT and p-mTOR proteins of PLGC cells were up-regulated.Compared with the PLGC group,the four extracts attenuated the proliferation,migration and invasion abilities of PLGC cells,down-regulated the protein expression levels of Vimentin,p-PI3K,p-AKT and p-mTOR,and upregulated E-cadherin ex-pression in cells of the SYM,YSYZ,and ZDC groups.There was no statistical significance in the SX group.In addition,there were significant differences in the chemical components of the four different polar extracts of Bombyx batryticatus.The differential compounds were cysteine,histidine,etc.Conclusions The four different polar extracts of Bombyx batryticatus all can exert in vitro anti-PLGC effects by regulating the PI3K/AKT/mTOR signaling pathway to inhibit the EMT process.Among them,the extract of n-butanol had the strongest activity,followed by the extracts of ethyl ace-tate and petroleum ether.The aqueous phase had the weakest activity,and the difference in activity may be related to the different compounds such as Cysteine and Histidine.
7.Resveratrol mediates miR-155 regulation of SIRT1 to inhibit myocardial injury in sepsis rats
Xiao-hang LU ; Yuan-yuan GAO ; Xiao-juan LI ; Xue-lian HU ; Yu-qiao WANG
The Chinese Journal of Clinical Pharmacology 2025;41(2):209-214
Objective To explore the protective effect of resveratrol on myocardial damage caused by sepsis in rats.Methods Forty SD rats were randomly divided into control group,model group,experimental group and combined group,with 10 rats in each group.Except the control group,the other rats were intraperitoneally injected with 20 mg·kg-1 lipopolysaccharide,while the control group was injected with the same amount of normal saline.Two hours before modeling,the experimental group and combinated group were given 50 mg·kg-1 resveratrol by gavage,and the control group and model group were given the same amount of normal saline by gavage.The combined group was injected with 10 nmol of micro RNA-155(miR-155)agomir through the tail vein,and the other group was injected with equal volume of normal saline through the tail vein.Left ventricular function parameters of rats were measured by echocardiography.The level of myocardial injury markers was detected by colorimetry.Quantitative reverse transcription polymerase chain reaction was used to detect the expression of miR-155.The expression of sirtuin 1(SIRT1)and related proteins of nuclear factor κB signaling pathway were detected by Western blot.Results The left ventricular ejection fraction of control group,model group and experimental group were(80.78±12.85)%,(55.92±7.86)%and(71.55±10.71)%,respectively;left ventricular fractional shortening were(34.08±5.75)%,(22.92±2.96)%,(28.72±4.25)%,respectively;left ventricular end disatolic diameter were(3.12±0.46),(6.34±0.69),(4.95±0.57)mm,respectively;the left ventricular end systolic diameter were(5.98±0.65),(7.24±0.80),(6.16±0.78)mm,respectively;the fractional shortening were(38.91±5.38)%,(22.67±3.53)%,(30.74±3.97)%,and the expression levels of creatine kinase-MB were(661.56±85.44),(1181.41±142.14),(915.02±105.19)U·L-1,respectively;the expressions levels of cardiac troponin Ⅰ were(148.17±28.48),(448.17±60.34)and(375.44±49.01)ng·mL-1,respectively.The expression of miR-155 in control group,model group,experimental group and combined group were 1.00±0.12,3.79±0.45,1.87±0.23 and 4.03±0.49,respectively;the protein relative expression levels of nuclear factor κB(NF-κB)were 1.00±0.08,5.04±0.59,2.73±0.35,5.58±0.63,respectively;the protein relative expression levels of inhibitor of NF-κB-β were 1.00±0.11,3.03±0.37,1.35±0.15 and 2.89±0.34,respectively;the protein relative expressions of inhibitor of NF-κB-α were 1.00±0.13,0.86±0.08,1.21±0.18,0.77±0.09,respectively;the protein relative expression levels of SIRT1 were 1.00±0.16,0.66±0.07,0.93±0.14,0.54±0.06,respectively.The above indicators of the model group were compared with the control group,the experimental group were compared with the model group,and the above indicators of the combined group were compared with the experimental group,and the differences were statistically significant(all P<0.05).Conclusion Resveratrol can alleviate myocardial injury and improve cardiac function in sepsis rats,which may be achieved by down-regulating the expression of miR-155,up-regulating the level of SIRT1,and inhibiting the nuclear factor κB signaling pathway.
8.Risk factors associated with hemodynamic instability in carotid artery stenting:a systematic review and meta-analysis
La-ting ZHANG ; Xiao-qing WANG ; Lin HAN ; Xin-hui LIANG ; Yao JIA ; Li-juan GAO ; Xue JIANG
Chinese Journal of Interventional Cardiology 2025;33(4):201-214
Objective To investigate the risk factors of hemodynamic instability after carotid artery stenting by meta-analysis.Methods Ten databases were searched:PubMed,ProQuest,ScienceDirect,Embase,Cochrane Library,Web of Science,China Knowledge Network,Wanfang Data,VIP Information Database,and China Biomedical Database.The search date was from inception until 2 February 2024,and meta-analysis was performed using Stata 16.0 statistical software.Results A total of 27 studies with 4199 subjects and 22 influencing factors were included.The studies showed a 37.4%(95%CI 30.3%-44.8%)incidence of haemodynamic instability after carotid stenting,Meta-analysis determined that age>60 years(P<0.001),hypertension(P<0.001),calcified plaque(P<0.001),stenosis>70%(P=0.008),eccentric plaque(P=0.002),distance from the largest stenosis to the carotid bifurcation≤ 10 mm(P<0.001),stenosis involvement of the balloon or bifurcation(P<0.001),balloon post-dilation(P=0.003),open-loop stenting(P<0.001),dilated balloon diameter≥5 mm(P=0.002),repeat balloon dilation(P=0.011)and balloon dilation pressure≥8 atm(P<0.001)are risk factors for intraoperative and postoperative haemodynamic instability in patients undergoing carotid artery stenting surgery.Statin use was a protective factor(P<0.001).Conclusions Medical staff working in the clinic should assess the patient's condition preoperatively,identify risk factors that may lead to haemodynamic instability,and avoid unnecessary intraoperative stimulation of patients who are already in a high-risk state.Reduce postoperative clinical complications in patients with carotid artery stenosis and improve patient recovery.
9.Study on transmission characteristics and genetic variation of carbapenem-resistant Klebsiella pneumonia based on whole genome sequencing
Jiachen LI ; Yanying CHEN ; Yanlei GE ; Jinrui HU ; Xiaoli DU ; Jinyue LIU ; Huan XING ; Pengfang GAO ; Xiao HAN ; Yuelong LI ; Yating TANG ; Juan LI ; Zhigang CUI ; Jinhui ZHANG ; Haijian ZHOU ; Aiying DONG
Chinese Journal of Preventive Medicine 2025;59(6):892-900
Objective:To analyze the short-term hospital-based transmission characteristics and gene variation of Carbapenem-Resistant Klebsiella pneumoniae (CRKP) by genome-wide technique to provide evidence for transmission control. Methods:The experimental strain was derived from all the CRKP isolated in Affiliated Hospital of North China University of Science and Technology from October 2022 to December 2023. Strain identification and drug susceptibility were tested with VITEK 2-Compact automatic bacterial identification drug susceptibility analyzer or disk method, and the results were interpreted through whole genome sequencing. The ST type, carbapenem resistance gene, virulence factor, and O serotype of the collected strains were analyzed.Results:Among the 115 strains of CRKP, 94 strains were isolated from the intensive care unit (ICU), accounting for 81.7%, and 21 strains were isolated from the non-intensive care unit (NICU), accounting for 18.3%. The 115 strains of CRKP can be divided into 11 ST types, of which ST11 type was the most (54.8%, 63/115), followed by ST15 type (22.6%, 26/115) and ST5492 type (15.7%, 18/115). Type ST5492 was a new clonal group in the region. The 115 strains of CRKP could be divided into 7 O serotypes, most of which were O2a type(32.2%,37/115), followed by O5 type(30.4%,35/115) and O1 type(27.8%,32/115). The resistance genes of carbapenem antibiotics showed that there were 107 strains carrying the blaKPC-2 gene, one strain with the blaNDM-1 gene, and one strain with both the blaKPC-2 and blaNDM-13 genes. Virulence genes were detected in 55 CRKP strains (47.8%, 55/115), among which six strains detected peg-344, iucA, iroB, rmpA, and rmpA2 virulence genes (5.2%, 6/115). Four virulence genes ( peg-344, iucA, rmpA, and rmpA2) were detected in 34 strains (29.6%, 34/115). Three virulence genes ( iucA, iroB and rmpA) were detected in two strains (1.7%, 2/115). Three virulence genes ( peg-344, iucA and rmpA) were detected in one strain (0.8%, 1/115). IucA and rmpA virulence genes were detected in 12 strains (10.4%, 12/115). KPC-2_ST11_O2a, KPC-2_ST15_O1 and KPC-2_ST5492_O5 were dominant clones, and their distribution was mainly in the intensive care unit. The whole genome sequence analysis showed that there were three dominant clones, among which ST11 clones were subdivided into three dominant O serotypes, all of which were mainly in the intensive care unit. Conclusion:The popular strain in the hospital of CRKP is a KPC-2_ST11 clone group carrying iucA, rmpA/rmpA2, with cross-department transmission and mutation. ST5492 is a newly-launched clone type. The intensive care unit of hvKP carrying five virulence genes, including peg-344, should be alert to the epidemic risk of CR-hvKP outbreak.
10.Genetic diversity analysis of oxacillinase in 241 clinical isolates of Pseudomonas aeruginosa
Yuelong LI ; Jingyi ZHANG ; Yubing FU ; Meiqing SUN ; Beibei MIAO ; Xinyi GONG ; Xiao HAN ; Huan XING ; Pengfang GAO ; Jiachen LI ; Yating TANG ; Xinya FAN ; Yanlei GE ; Haijian ZHOU ; Juan LI ; Aiying DONG
Chinese Journal of Preventive Medicine 2025;59(7):1004-1012
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.


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