Objective:To understand the etiological surveillance and drug resistance characteristics of Legionella pneumophila (LP) from the aqueous environment of public places in Shanghai, from 2011 to 2020, and provide evidence for surveillance of the disease. Methods:Environmental water samples were systematically collected from public venues in urban and suburban districts of Shanghai for LP surveillance. All the identified LP isolates underwent a series of testings including serotyping, pulsed field gel electrophoresis (PFGE), sequence-based typing, and antimicrobial susceptibility testing. χ2 test or Cochran-Armitage trend tests were used for statistical analysis and for temporal resistance patterns. Results:Among 6 263 water samples, the LP-positive rate was 20.93% (1 311/6 263). The positivity rate decreased from 24.98% (287/1 149) in 2011-2012 to 20.02% (1 024/5 114) in 2013-2020 ( χ2=13.92, P<0.001), with the highest monthly positivity observed from June to August (23.79%, 745/3 132). A total of 1 365 LP strains were isolated, of which 912 were further characterized, including 10 serotypes, 149 PFGE patterns, and 33 sequence types (ST). The predominant serotype was Lp1 (86.84%, 792/912), and the dominant ST was ST752 (29.50%, 269/912). ST clustering revealed two major clonal groups CG1 and CG2, accounting for 91.12% (831/912) of the isolates. The 190 LPs involved in the drug sensitivity test showed three resistance profiles: azithromycin resistance (31.05%, 59/190), ciprofloxacin resistance (0.53%, 1/190) and azithromycin+ciprofloxacin resistance (0.53%, 1/190). Azithromycin-resistant strains were predominantly ST1 (64.41%, 38/59). The antimicrobial resistance rate showed a significant decline, from 48.65% (18/37) in 2011-2012 to 28.10% (43/153) in 2013-2020 ( χ2=9.38, P=0.002). Conclusions:Compared to from 2011 to 2012, both the positivity rate and antimicrobial resistance prevalence of LP in public aqueous environments of Shanghai exhibited an overall decline from 2013 to 2020. The predominant types of LP were serotype Lp1 and sequence type ST752, with notable high-level resistance to azithromycin. Measures as enhancing the enforcement of water safety regulations and prioritizing surveillance of azithromycin resistance in LP were recommended to mitigate public health risks.

Objective To investigate the distribution characteristics of Klebsiella pneumoniae(KP),hyperviru-lent Klebsiella pneumoniae(hvKP),carbapenem-resistant Klebsiella pneumoniae(CRKP),and hypervirulent car-bapenem-resistant Klebsiella pneumoniae(hv-CRKP/CR-hvKP)in the environment of general intensive care unit(ICU)at medical institutions,and provide reference for environment assessment as well as healthcare-associated in-fection(HAI)prevention and control in ICU.Methods A total of 3 336 environmental specimens were collected from general ICUs of medical institutions in Shanghai in 2019 and 2023.After strain isolation,antimicrobial suscep-tibility testing and whole genome sequencing were conducted.Results The detection rate of KP was 1.59％(n=53),among which hvKP,CRKP,and hv-CRKP/CR-hvKP accounted for 37.74％(20/53),52.83％(28/53),and 24.53％(13/53)of the total detected strains,respectively.The main types of hvKP were ST11-KL64 and ST11-KL25,CRKP were ST15-KL19 and ST11-KL25,hv-CRKP/CR-hvKP were ST11-KL25 and ST11-KL64.The main carried resistance genes included fosA,oqx AB,tet(A),blaTEM-1B,blaKPC-2,qnrS11,etc.All strains carried viru-lence genes fimH,iutA,ent A,entB,entC,entD,entE,and entF,with only one strain carrying rmp A gene.Conclusion KP contamination is widespread in general ICU environment of medical institutions,predominantly ST11 and ST15,presenting a polymorphic distribution.CRKP and hvKP account for a relatively high proportion,and multidrug resistance is serious.Co-evolution of drug resistance and virulence presents in KP,and poses signifi-cant infection and pathogenic risks to patients,necessitating enhanced clinical vigilance and preparedness for poten-tial outbreaks.

Objective:To understand the etiological surveillance and drug resistance characteristics of Legionella pneumophila (LP) from the aqueous environment of public places in Shanghai, from 2011 to 2020, and provide evidence for surveillance of the disease. Methods:Environmental water samples were systematically collected from public venues in urban and suburban districts of Shanghai for LP surveillance. All the identified LP isolates underwent a series of testings including serotyping, pulsed field gel electrophoresis (PFGE), sequence-based typing, and antimicrobial susceptibility testing. χ2 test or Cochran-Armitage trend tests were used for statistical analysis and for temporal resistance patterns. Results:Among 6 263 water samples, the LP-positive rate was 20.93% (1 311/6 263). The positivity rate decreased from 24.98% (287/1 149) in 2011-2012 to 20.02% (1 024/5 114) in 2013-2020 ( χ2=13.92, P<0.001), with the highest monthly positivity observed from June to August (23.79%, 745/3 132). A total of 1 365 LP strains were isolated, of which 912 were further characterized, including 10 serotypes, 149 PFGE patterns, and 33 sequence types (ST). The predominant serotype was Lp1 (86.84%, 792/912), and the dominant ST was ST752 (29.50%, 269/912). ST clustering revealed two major clonal groups CG1 and CG2, accounting for 91.12% (831/912) of the isolates. The 190 LPs involved in the drug sensitivity test showed three resistance profiles: azithromycin resistance (31.05%, 59/190), ciprofloxacin resistance (0.53%, 1/190) and azithromycin+ciprofloxacin resistance (0.53%, 1/190). Azithromycin-resistant strains were predominantly ST1 (64.41%, 38/59). The antimicrobial resistance rate showed a significant decline, from 48.65% (18/37) in 2011-2012 to 28.10% (43/153) in 2013-2020 ( χ2=9.38, P=0.002). Conclusions:Compared to from 2011 to 2012, both the positivity rate and antimicrobial resistance prevalence of LP in public aqueous environments of Shanghai exhibited an overall decline from 2013 to 2020. The predominant types of LP were serotype Lp1 and sequence type ST752, with notable high-level resistance to azithromycin. Measures as enhancing the enforcement of water safety regulations and prioritizing surveillance of azithromycin resistance in LP were recommended to mitigate public health risks.

Objective To investigate the distribution characteristics of Klebsiella pneumoniae(KP),hyperviru-lent Klebsiella pneumoniae(hvKP),carbapenem-resistant Klebsiella pneumoniae(CRKP),and hypervirulent car-bapenem-resistant Klebsiella pneumoniae(hv-CRKP/CR-hvKP)in the environment of general intensive care unit(ICU)at medical institutions,and provide reference for environment assessment as well as healthcare-associated in-fection(HAI)prevention and control in ICU.Methods A total of 3 336 environmental specimens were collected from general ICUs of medical institutions in Shanghai in 2019 and 2023.After strain isolation,antimicrobial suscep-tibility testing and whole genome sequencing were conducted.Results The detection rate of KP was 1.59％(n=53),among which hvKP,CRKP,and hv-CRKP/CR-hvKP accounted for 37.74％(20/53),52.83％(28/53),and 24.53％(13/53)of the total detected strains,respectively.The main types of hvKP were ST11-KL64 and ST11-KL25,CRKP were ST15-KL19 and ST11-KL25,hv-CRKP/CR-hvKP were ST11-KL25 and ST11-KL64.The main carried resistance genes included fosA,oqx AB,tet(A),blaTEM-1B,blaKPC-2,qnrS11,etc.All strains carried viru-lence genes fimH,iutA,ent A,entB,entC,entD,entE,and entF,with only one strain carrying rmp A gene.Conclusion KP contamination is widespread in general ICU environment of medical institutions,predominantly ST11 and ST15,presenting a polymorphic distribution.CRKP and hvKP account for a relatively high proportion,and multidrug resistance is serious.Co-evolution of drug resistance and virulence presents in KP,and poses signifi-cant infection and pathogenic risks to patients,necessitating enhanced clinical vigilance and preparedness for poten-tial outbreaks.

Background The incidence of Legionnaires' disease is increasing globally and artificial water environment is becoming a common source of outbreaks. Molecular typing techniques can help prevent and control Legionella. Objective To understand the molecular epidemiological characteristics of Legionella pneumophila in artificial water environment of Shanghai hospitals, and provide a scientific basis for the prevention and control of Legionnaires' disease. Methods Water samples were collected from artificial water environment in 14 hospitals from May to October each year from 2019 to 2020 in Shanghai. A total of 984 water samples were collected from 8 Grade-A tertiary hospitals and 6 non-Grade-A tertiary hospitals, including 312 samples of cooling water, 72 samples of chilled water, and 600 samples of tap water. The water samples were isolated and serotyped for Legionella pneumophila and preserved, and the positive rate of Legionella pneumophila in the samples was used as an indicator of contamination. The preserved strains were resuscitated and 81 surviving strains were obtained for pulsed field gel electrophoresis (PFGE) typing analysis. Results A total of 124 Legionella pneumophila positive water samples were detected, with a positive rate of 12.60%. The positive rate was higher in the Grade-A tertiary hospitals (16.54%, 87/526) than in the non-Grade-A tertiary hospitals (8.08%, 37/458) (χ²=15.91, P<0.001). The positive rate of cooling water (23.40%) was the highest among different types of water samples, and the difference was statistically significant (χ²=61.19, P<0.001). The difference in positive rate of tap water was statistically significant among different hospital departments (χ²=11.37, P<0.05). The positive rate in 2019 (15.06%) was higher than that in 2020 (9.84%) (χ²=6.23, P<0.05). From May to October, August had the highest annual average positive rate (16.46%) and October had the lowest (8.54%), but the difference in positive rates among months was not statistically significant (χ²=5.39, P=0.37). The difference in positive rate among districts was statistically significant (χ²=24.88, P<0.001). A total of 131 strains of Legionella pneumophila were isolated, with serotype 1 (80.15%, 105/131) predominating. Among the 81 surviving strains of Legionella pneumophila subjected to PFGE typing, the band-based similarity coefficients ranged from 41.30% to 100%. Among the 29 PFGE band types (S1-S29) recorded, each band type included 1-10 strains, and S28 was the dominant band type. Four clusters (I-IV) of PFGE band types were identified, accounting for 66.67% (54/81) of all strains and containing 13 band types. Conclusion Legionella pneumophila contamination is present in the artificial water environment of hospitals in Shanghai from 2019 to 2020, and the contamination in tap water deserves attention. The detected serotype of Legionella pneumophila is predominantly type 1, and PFGE typing reveals the presence of genetic polymorphism. Therefore, the monitoring and control of Legionella pneumophila in hospital artificial water environment should be strengthened.

OBJECTIVE: To elucidate the pathogenic role of leukotriene B4 (LTB4) in pulmonary hyper-permeability and inflammation induced by lung-protective mechanical ventilation (LPMV) in rabbits. METHODS: Thirty-two healthy Japanese white rabbits were randomized into 4 groups for treatment with vehicle or bestatin (a leukotriene A4 hydrolase inhibitor that inhibits LTB4 production) administered intragastrically at the daily dose of 8 mg/kg for 5 days, followed by sham operation (group S and group BS, respectively, in which the rabbits were anesthetized only) or LPMV (group PM and group BPM, respectively, in which the rabbits received ventilation with 50% oxygen at a tidal volume of 8 mL/kg for 5 h). The concentrations of LTB4 and cyclic adenosine monophosphate (cAMP) in the lung tissues were analyzed by ELISA. cAMP content, protein kinase A (PKA) protein expression and the Rap1-GTP protein to total Rap1 protein ratio were determined to assess the activities of cAMP/PKA and Rap1 signaling pathways. The lung injury was evaluated by assessing lung permeability index, lung wet/dry weight ratio, polymorphonuclear leukocyte (PMN) count in bronchoalveolar lavage fluid (BALF), pulmonary myeloperoxidase (MPO) activity and lung histological scores. RESULTS: None of the examined parameters differed significantly between group S and group BS. All the parameters with the exception of lung histological score increased significantly in group PM and group BPM as compared to those in group S ( CONCLUSIONS LPMV can induce LTB4 overproduction to down-regulate cAMP/PKA and Rap1 signaling pathways in the lungs of rabbits, which results in lung hyper-permeability and inflammation. Bestatin can inhibit LTB4 production in the lungs to protect against LPMV-induced lung hyper-permeability and inflammation.
Animals ; Bronchoalveolar Lavage Fluid ; Leukotriene B4 ; Lung ; Lung Injury/prevention & control* ; Neutrophils ; Rabbits ; Respiration, Artificial/adverse effects*