OBJECTIVE:To establish a method for determination of dextran70 in Compound dextran70 eye drop. METHODS:HPLC-RID was performed on the column of Phenomenex PolySep-GFC-P 4000 with the mobile phase of 0.7% Na2SO4 solution. The flow rate was 0.5 ml/min,column temperature was 35 ℃ and injection volume was 50 μl,and the inner temperature of refrac-tive index detector was 40 ℃. RESULTS:The linear range of dextran70 was 0.1-5.0 mg/ml(r=0.999 5);RSDs of precision,sta-bility and reproducibility tests were lower than 2%;average recovery was 97.45%-101.76%(RSD=0.57%,n=9). CONCLU-SIONS:The method is simple,fast and reliable with high separation and short analysis time,and can be used for the content deter-mination of dextran70 in Compound dextran70 eye drop.

Background It is imperative for the microbial monitor after opening the bottle of eyedrops in order to ensure the safety during use of ophthalmic solutions with multi-dose packaging.Objective This study was to research the microbiological properties and sterile duration of methylcellulose (MC) eye drops in three common environmental conditions,including room temperature condition of community,refrigeration condition of community and room temperature condition of hospital.Methods MC eye drops were assigned to the community room temperature group,community refrigeration group and hospital room temperature group,and 200 bottles of MC eye drops with or without ethylparaben were collected in each group,including sealed or unsealed drugs at average.The containers of all the eye drops were opened and the opening times were record.The drugs was admistered 1 drop for 3 times per day,with the opening period for 5-10 seconds.Then the drugs were preserved in different environments based on grouping.Microbial isolation and purification were performed by the same lab technician at 8:00 from 1 through 10 days after opening of drugs with automatic microbial analyzer.Results In the unsealed MC eye drops without ethylparaben,the bacterial positive rates were about 30％ in the community room temperature group,community refrigeration group and hospital room temperature group,but no microbial colony was seen in the sealed eye drops.Ten days after opening of containers,the bacterial cultured rates were 30％,32％ and 36％ in the eye drops without ethylparaben in the community room temperature group,community refrigeration group and hospital room temperature group,and those in the eye drops with ethylparaben were 15％,19％ and 23％,respectively,showing significant differences between the eye drops with and without ethylparaben (x2 =6.452,4.448,4.063,all at P＜0.05).The 95％ confidence interval (CI) of difference values of intergroup bacterial rates were-0.166-0.126,-0.110-0.190 and-0.088-0.208 between the community room temperature group and the community refrigeration group,between the hospital room temperature group and the community refrigeration group,between the hospital room temperature group and the community room temperature group respectively in the unsealed eye drops without ethylparaben,and those in the unsealed eye drops with ethylparaben were-0.159-0.079,-0.089-0.169 and-0.043-0.203 respectively,indicating insignificant differences among the groups.Cultured bacteria were identified as Micrococcus luteus,Acinetobacter lwoffii,Bacillus subtilis,Acinetobacter radioresistens,Myroides and Staptococcus xylosus.Conclusions Ethylparaben can reduce the contamination rate of microorganisms after opening of MC eye drops.Three environmental conditions do not play an influence on microbial contamination of MC eye drops after opening.The bacteria of contaminated eye drops appear to be common microorganisms in atmosphere and soil,rather than eye common pathogens.

OBJECTIVE： To investigate the occurrence and influencing factors of dry eye in patients with topical use of anti-glaucoma drugs， and to provide reference for the prevention and treatment of dry eye in glaucoma patients. METHODS： Totally 600 patients receiving topical use of anti-glaucoma drugs were selected from our hospital as research objects during Jun. 2015 to Jun. 2018. The ophthalmologic examination and questionnaire survey were carried out. The univariate analysis and multivariate Logistic regression analysis were conducted for influencing factors of dry eye. RESULTS： A total of 600 questionnaires were distributed and 547 questionnaires were recovered， with a recovery rate of 91.17％. Of the 547 patients who withdrew the questionnaire， 36 patients refused to undergo further examination， 19 patients were excluded， and a total of 492 patients were included in the study.Of 492 patients treated with topical anti-glaucoma drugs， there were 262 dry eye patients with incidence of 53.25％. Top 3 symptoms of dry eye were dryness， burning and foreign body sensation， involving 182 cases （69.47％）， 159 cases （60.69％） and 106 cases （40.46％）. The results of univariate analysis showed that there was statistical significance in the difference of gender， age， sleep quality， use of video display terminals， dry environment， medication time， medication types， medication frequency， medication with or without traditional preservatives， pterygium， tarsal gland dysfunction between 2 groups （P＜0.05）. Multivariate Logistic regression analysis showed that gender， medication time， medication type， medication with or without traditional preservatives， tarsal gland dysfunction and video display terminals were risk factors for the occurrence of dry eye in glaucoma patients （OR were 1.613-2.477）. CONCLUSIONS： The incidence of dry eye in patients treated with topical use of anti-glaucoma drug is high. The clinicians should take the prevention and treatment measures according to its risk factors， such as gender， medication time， medication type， medication with or without traditional preservatives， tarsal gland dysfunction and video display terminals， and minimize ocular discomfort in patients with dry eyes so as to improve the therapeutic compliance of glaucoma patients.

Objective: To study the distribution and pharmacokinetics of cefuroxime in rabbit eyes after intravenous administration. Methods: Thirty-five rabbits were randomly divided into 7 groups by random number table method, with 5 rabbits in each group.The rabbits in blank control group were feed without any treatment, the rest rabbits were injected with 40.63 mg/kg cefuroxime intravenously.The rabbits were sacrificed at 0.5 hour, 1.0 hour, 1.5, 2.0, 2.5 and 3.0 hours after injection, and the eyeballs were immediately dissected.The concentration of drug in different ocular tissues was detected by high performance liquid chromatography, and the pharmacokinetic parameters in eyes were computed by the DAS software.This study was approved by the Experimental Animal Ethics Committee of Shanxi Provincial Eye Hospital (201802b). Results: The peak concentrations (Cmax) of cefuroxime were (11.63±0.20), (1.59±0.05), (1.51±0.08), (0.99±0.07), (1.55±0.08) and (8.57±0.17)μg/ml in aqueous humor, iris-ciliary body, vitreous body, retinal-choroid, cornea and sclera, respectively.The times to peak (Tmax) were 1.5 hours, 1.0, 1.0, 0.5, 1.0 and 0.5 hour in aqueous humor, iris-ciliary body, vitreous body, retinal-choroid, cornea and sclera, respectively.The areas under drug time curve (AUC_0-t) were (26.60±0.62), (6.22±0.84), (5.86±0.16), (3.75±0.45), (5.50±0.15) and (26.48±0.73)(μg·h)/ml in aqueous humor, iris-ciliary body, vitreous body, retinal-choroid, cornea and sclera, respectively.Cefuroxime was not detected in the lens at different time points after injection.The parameters of pharmacokinetics were fitted to two compartment model. Conclusions Cefuroxime shows good penetration in aqueous humor, iris-ciliary body, vitreous body, retinal-choroid, cornea and sclera when administrated by intravenous injection in rabbits and cefuroxime has no distribution in lens.Cefuroxime can reach an effective concentration in ocular tissues 0.5 to 1.5 hours after intravenous injection.

Objective To investigate the antimicrobial resistance profile of the clinical isolates collected from selected hospitals across China. Methods Twenty-nine general hospitals and five children's hospitals were involved in this program. Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems. Results were interpreted according to CLSI 2017 breakpoints. Results A total of 190 610 clinical isolates were collected from January to December 2017, of which gram negative organisms accounted for 70.8％ (134 951/190 610) and gram positive cocci 29.2％ (55 649/190 610). The prevalence of methicillin-resistant strains was 35.3％ in S. aureus (MRSA) and 80.3％ in coagulase negative Staphylococcus (MRCNS) on average. MR strains showed much higher resistance rates to most of the other antimicrobial agents than MS strains. However, 91.6％ of MRSA strains were still susceptible to trimethoprim-sulfamethoxazole, while 86.2％ of MRCNS strains were susceptible to rifampin. No staphylococcal strains were found resistant to vancomycin. E. faecalis strains showed much lower resistance rates to most of the drugs tested (except chloramphenicol) than E. faecium. Vancomycin-resistant Enterococcus (VRE) was identified in both E. faecalis and E. faecium. The identified VRE strains were mainly vanA, vanB or vanM type based on phenotype or genotype. The proportion of PSSP or PRSP strains in the non-meningitis S.pneumoniae strains isolated from children decreased but the proportion of PISP strains increased when compared to the data of 2016. Enterobacteriaceae strains were still highly susceptible to carbapenems. Overall, less than 10％ of these strains (excluding Klebsiella spp.) were resistant to carbapenems. The prevalence of imipenem-resistant K. pneumoniae increased from 3.0％ in 2005 to 20.9％ in 2017, and meropenem-resistant K. pneumoniae increased from 2.9％ in 2005 to 24.0％ in 2017, more than 8-fold increase. About 66.7％ and 69.3％ of Acinetobacter (A. baumannii accounts for 91.5％) strains were resistant to imipenem and meropenem, respectively. Compared with the data of year 2016, P. aeruginosa strains showed decreasing resistance rate to carbapenems. Conclusions Bacterial resistance is still on the rise. It is necessary to strengthen hospital infection control and stewardship of antimicrobial agents. The communication between laboratorians and clinicians should be further improved in addition to surveillance of bacterial resistance.

Objective To investigate the distribution and antimicrobial resistance profiles of the common pathogens isolated from urine from 2015 to 2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods The bacterial strains were isolated from urine and identified routinely in 51 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Antimicrobial susceptibility was determined by Kirby-Bauer method,automatic microbiological analysis system and E-test according to the unified protocol.Results A total of 261 893 nonduplicate strains were isolated from urine specimen from 2015 to 2021,of which gram-positive bacteria accounted for 23.8％(62 219/261 893),and gram-negative bacteria 76.2％(199 674/261 893).The most common species were E.coli(46.7％),E.faecium(10.4％),K.pneumoniae(9.8％),E.faecalis(8.7％),P.mirabilis(3.5％),P.aeruginosa(3.4％),SS.agalactiae(2.6％),and E.cloacae(2.1％).The strains were more frequently isolated from inpatients versus outpatients and emergency patients,from females versus males,and from adults versus children.The prevalence of ESBLs-producing strains in E.coli,K.pneumoniae and P.mirabilis was 53.2％,52.8％and 37.0％,respectively.The prevalence of carbapenem-resistant strains in E.coli,K.pneumoniae,P.aeruginosa and A.baumannii was 1.7％,18.5％,16.4％,and 40.3％,respectively.Lower than 10％of the E.faecalis isolates were resistant to ampicillin,nitrofurantoin,linezolid,vancomycin,teicoplanin and fosfomycin.More than 90％of the E.faecium isolates were ressitant to ampicillin,levofloxacin and erythromycin.The percentage of strains resistant to vancomycin,linezolid or teicoplanin was＜2％.The E.coli,K.pneumoniae,P.aeruginosa and A.baumannii strains isolated from ICU inpatients showed significantly higher resistance rates than the corresponding strains isolated from outpatients and non-ICU inpatients.Conclusions E.coli,Enterococcus and K.pneumoniae are the most common pathogens in urinary tract infection.The bacterial species and antimicrobial resistance of urinary isolates vary with different populations.More attention should be paid to antimicrobial resistance surveillance and reduce the irrational use of antimicrobial agents.

Objective To understand the distribution and changing resistance profiles of clinical isolates of Enterococcus in hospitals across China from 2015 to 2021.Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Enterococcus according to the unified protocol of CHINET program by automated systems,Kirby-Bauer method,or E-test strip.The results were interpreted according to the Clinical & Laboratory Standards Institute(CLSI)breakpoints in 2021.WHONET 5.6 software was used for statistical analysis.Results A total of 124 565 strains of Enterococcus were isolated during the 7-year period,mainly including Enterococcus faecalis(50.7％)and Enterococcus faecalis(41.5％).The strains were mainly isolated from urinary tract specimens(46.9％±2.6％),and primarily from the patients in the department of internal medicine,surgery and ICU.E.faecium and E.faecalis strains showed low level resistance rate to vancomycin,teicoplanin and linezolid(≤3.6％).The prevalence of vancomycin-resistant E.faecalis and E.faecium was 0.1％and 1.3％,respectively.The prevalence of linezolid-resistant E.faecalis increased from 0.7％in 2015 to 3.4％in 2021,while the prevalence of linezolid-resistant E.faecium was 0.3％.Conclusions The clinical isolates of Enterococcus were still highly susceptible to vancomycin,teicoplanin,and linezolid,evidenced by a low resistance rate.However,the prevalence of linezolid-resistant E.faecalis was increasing during the 7-year period.It is necessary to strengthen antimicrobial resistance surveillance to effectively identify the emergence of antibiotic-resistant bacteria and curb the spread of resistant pathogens.

Objective To examine the changing antimicrobial resistance profile of Enterobacter spp.isolates in 53 hospitals across China from 2015 t0 2021.Methods The clinical isolates of Enterobacter spp.were collected from 53 hospitals across China during 2015-2021 and tested for antimicrobial susceptibility using Kirby-Bauer method or automated testing systems according to the CHINET unified protocol.The results were interpreted according to the breakpoints issued by the Clinical & Laboratory Standards Institute(CLSI)in 2021(M100 31st edition)and analyzed with WHONET 5.6 software.Results A total of 37 966 Enterobacter strains were isolated from 2015 to 2021.The proportion of Enterobacter isolates among all clinical isolates showed a fluctuating trend over the 7-year period,overall 2.5％in all clinical isolates amd 5.7％in Enterobacterale strains.The most frequently isolated Enterobacter species was Enterobacter cloacae,accounting for 93.7％(35 571/37 966).The strains were mainly isolated from respiratory specimens(44.4±4.6)％,followed by secretions/pus(16.4±2.3)％and urine(16.0±0.9)％.The strains from respiratory samples decreased slightly,while those from sterile body fluids increased over the 7-year period.The Enterobacter strains were mainly isolated from inpatients(92.9％),and only(7.1±0.8)％of the strains were isolated from outpatients and emergency patients.The patients in surgical wards contributed the highest number of isolates(24.4±2.9)％compared to the inpatients in any other departement.Overall,≤ 7.9％of the E.cloacae strains were resistant to amikacin,tigecycline,polymyxin B,imipenem or meropenem,while ≤5.6％of the Enterobacter asburiae strains were resistant to these antimicrobial agents.E.asburiae showed higher resistance rate to polymyxin B than E.cloacae(19.7％vs 3.9％).Overall,≤8.1％of the Enterobacter gergoviae strains were resistant to tigecycline,amikacin,meropenem,or imipenem,while 10.5％of these strains were resistant to polycolistin B.The overall prevalence of carbapenem-resistant Enterobacter was 10.0％over the 7-year period,but showing an upward trend.The resistance profiles of Enterobacter isolates varied with the department from which they were isolated and whether the patient is an adult or a child.The prevalence of carbapenem-resistant E.cloacae was the highest in the E.cloacae isolates from ICU patients.Conclusions The results of the CHINET Antimicrobial Resistance Surveillance Program indicate that the proportion of Enterobacter strains in all clinical isolates fluctuates slightly over the 7-year period from 2015 to 2021.The Enterobacter strains showed increasing resistance to multiple antimicrobial drugs,especially carbapenems over the 7-year period.

Objective To understand the changing distribution and antimicrobial resistance profiles of Proteus,Morganella and Providencia in hospitals across China from January 1,2015 to December 31,2021 in the CHINET Antimicrobial Resistance Surveillance Program.Methods Antimicrobial susceptibility testing was carried out following the unified CHINET protocol.The results were interpreted in accordance with the breakpoints in the 2021 Clinical & Laboratory Standards Institute(CLSI)M100(31 st Edition).Results A total of 32 433 Enterobacterales strains were isolated during the 7-year period,including 24 160 strains of Proteus,6 704 strains of Morganella,and 1 569 strains of Providencia.The overall number of these Enterobacterales isolates increased significantly over the 7-year period.The top 3 specimen source of these strains were urine,lower respiratory tract specimens,and wound secretions.Proteus,Morganella,and Providencia isolates showed lower resistance rates to amikacin,meropenem,cefoxitin,cefepime,cefoperazone-sulbactam,and piperacillin-tazobactam.For most of the antibiotics tested,less than 10％of the Proteus and Morganella strains were resistant,while less than 20％of the Providencia strains were resistant.The prevalence of carbapenem-resistant Enterobacterales(CRE)was 1.4％in Proteus isolates,1.9％in Morganella isolates,and 15.6％in Providencia isolates.Conclusions The overall number of clinical isolates of Proteus,Morganella and Providencia increased significantly in the 7-year period from 2015 to 2021.The prevalence of CRE strains also increased.More attention should be paid to antimicrobial resistance surveillance and rational antibiotic use so as to prevent the emergence and increase of antimicrobial resistance.

Objective To understand the changing distribution and antimicrobial resistance profiles of Klebsiella strains in 52 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods Antimicrobial susceptibility testing was carried out according to the unified CHINET protocol.The susceptibility results were interpreted according to the breakpoints in the Clinical & Laboratory Standards Institute(CLSI)M100 document.Results A total of 241,549 nonduplicate Klebsiella strains were isolated from 2015 to 2021,including Klebsiella pneumoniae(88.0％),Klebsiella aerogenes(5.8％),Klebsiella oxytoca(5.7％),and other Klebsiella species(0.6％).Klebsiella strains were mainly isolated from respiratory tract(48.49±5.32)％.Internal medicine(22.79±3.28)％,surgery(17.98±3.10)％,and ICU(14.03±1.39)％were the top 3 departments where Klebsiella strains were most frequently isolated.K.pneumoniae isolates showed higher resistance rate to most antimicrobial agents compared to other Klebsiella species.Klebsiella isolates maintained low resistance rates to tigecycline and polymyxin B.ESBLs-producing K.pneumoniae and K.oxytoca strains showed higher resistance rates to all the antimicrobial agents tested compared to the corresponding ESBLs-nonproducing strains.The K.pneumoniae and carbapenem-resistant K.pneumoniae(CRKP)strains isolated from ICU patients demonstrated higher resistance rates to majority of the antimicrobial agents tested than the strains isolated from non-ICU patients.The CRKP strains isolated from adult patients had higher resistance rates to most of the antimicrobial agents tested than the corresponding CRKP strains isolated from paediatric patients.Conclusions The prevalence of carbapenem-resistant strains in Klebsiella isolates increased greatly from 2015 to 2021.However,the Klebsiella isolates remained highly susceptible to tigecycline and polymyxin B.Antimicrobial resistance surveillance should still be strengthened for Klebsiella strains.