Objective To analyze the antimicrobial resistance profile and homology of the Acinetobacter baumannii strains isolated from Rushan People's Hospital in a three-year period for better control of hospital infections.Methods A.baumannii strains were isolated from clinical specimens during the period from 2013 to 2015.Homology analysis were conducted by pulsed field gel electrophoresis (PFGE) for 60 randomly selected isolates.Results A total of 567 A.baumannii isolates were isolated,85 isolates in 2013,156 in 2014,and 326 in 2015.These isolates were mainly from Department of Respiratory Diseases (47.4％) and ICU (23.8 ％).Overall,62.1％ of the isolates were from sputum specimens followed by secretions (15.2％).All isolates were sensitive to polymyxin B,but all resistant to sulfamethoxazole and ampicillin.The A.baumannii isolates showed increasing resistance rate to imipenem,meropenem,ceftriaxone,and trimethoprim-sulfamethoxazole over the 3-year period,but decreasing resistance rate to gentamicin.The 60 selected isolates were grouped into 4 types by PFGE.A-type was the main pattern.Conclusions A.baumannii strains were mainly isolated from inpatients with respiratory tract infections.The A.baumannii strains showed serious antimicrobial resistance associated with possible clonal spread in this hospital.

Objective To analyze the distribution and antibiotic resistance of the microorganisms isolated from blood samples in the Cardiovascular Institute,Beijing Fuwai Hospital,for clinicians to improve antimicrobial therapy.Methods Blood samples were cultured and bacterial isolates were identified and tested for their susceptibility to antimicrobial agents.Results A total of 2 017 (8.3％) strains of microorganisms were isolated from 24 348 blood samples.Finally,1 009 nonduplicate strains were analyzed,including gram positive cocci (n=574,56.9％),gram negative bacilli (381,37.8％),and Candida species (54,5.4％).The top gram positive cocci were coagulase-negative Staphylococcus (31.8％),Streptococcus (11.0％),Staphylococcus aureus (5.5％),Enterococcus faecalis (4.0％),and Enterococcus faecium (1.5％).The top gram negative bacilli were Acinetobacter baumannii (6.7％),Pseudomonas aeruginosa (6.0％),Escherichia coli (5.7％),Klebsiella pneumoniae (4.3％),Stenotrophornonas maltophilia (3.5％),and Enterobacter cloacae (3.3％).Candida albicans was the most frequently isolated Candida species.Staphylococcus isolates were sensitive to linezolid,vancomycin,tigecycline,and quinupristin-dalfopristin.Enterococcusfaecalis were sensitive to linezolid,tigecycline,high level streptomycin,high level gentamicin,penicillin,ampicillin,and vancomycin.Enterococcus faecium were less sensitive than Enterococcus faecalis.All Enterococcus strains were sensitive to linezolid,tigecycline,high level streptomycin,high level gentamicin,and vancomycin.Gram negative bacilli were relatively sensitive to cefoperazone-sulbactam,piperacillin-tazobactam,cefepime,amikacin and carbapenems.A.baumannii and P.aeruginosa isolates showed lower susceptibility to carbapenems than E.coli,K.pneumoniae and E.cloacae.Conclusions The distribution of the pathogens isolated from blood samples was relatively stable in the past five years in our hospital.Gram positive cocci are more prevalent than gram negative bacilli in blood samples.Clinicians should select antimicrobial agents according to the distribution of pathogens and the antimicrobial resistance profile.

Objective To investigate the distribution and antibiotic resistance profile of clinical isolates in the First Hospital of Qiqihar during 2015.Methods Antimicrobial susceptibility test was carried out according to a unified protocol using automated system from January 1,2015 to December 31,2015.The results were analyzed with WHONET 5.6 software according to the 2014 breakpoints of Clinical and Laboratory Standards Institute.Results A total of 5 162 clinical isolates were collected,of which 28.1％ (1 450/5 162) were gram-positive cocci and 71.9％ (3 712/5 162) were gram-negative bacilli.About 36.5％ (255/698) ofS.aureus isolates and 81.4％ (180/221) of coagulase negative Staphylococcus isolates were resistant to methicillin.No S.aureus and coagulase negative Staphylococcus isolate were found resistant to vancomycin or linezolid.Enterococcus isolates showed low resistance to vancomycin and linezolid.One strain of E.faecium was found resistant to vancomycin.ESBLs were produced in 39.9％ (298/747) ofE.coli,26.1％ (294/1 127) ofKlebsiella spp.,and 15.6％ (12/77) ofP mirabilis strains.The Enterobacteriaceae strains were less resistant to imipenem,beta-lactam/beta-lactamase inhibitor combination and amikacin.About 36.6％ (163 / 445) of A.baumannii isolates and 1.8％ (13/715) of P.aeruginosa isolates were extensively drug-resistant strains.Conclusions Antibiotic resistance poses a serious threat to clinical practice,to which more attention should be paid.Clinical microbiology lab should make more efforts to provide better support to clinical therapy.

Objective To investigate the resistance rates of the Candida albicans strains isolated from patients with vulvovaginal candidiasis to 5 antifungal agents and examine the mechanism of azole resistance in these strains.Methods A total of 1 646 C.albicans strains were collected in Obstetrics and Gynecology Hospital of Fudan University from January to December 2015.The resistance rates of these isolates to five antifungal agents were analyzed.Azole-resistant (n=30),dose dependent sensitive (S-DD) (n=13),and susceptible isolates (n=10) were randomly selected from the microbiology laboratories of three obstetrics and gynecology hospitals in Shanghai.The expression levels of drug efflux pump related gene CDR1,CDR2,MDR1 and drug target enzyme gene ERG11 were analyzed by real-time fluorescence quantitative polymerase chain reaction (PCR).At the same time,the ERG11 and ERG3 genes were amplified by PCR and sequenced,and analyzed for resistance-related mutations.Results Of the 1 646 C.albicans strains,5.2％,3.2％,2.5％ and 2.1％ were resistant to itraconazole,voriconazole,fluconazole and 5-fluorocytosine,respectively.All isolates were sensitive to amphotericin B.The expression of ERG11 gene was significantly higher in S-DD group and azole-resistant group than in azole-sensitive group (P＜0.05).The expression of CDR1,CDR2 and MDR1 did not show significant difference among the three groups.There were 13 missense mutations in the ERG11 gene,of which T123I,P98S and Y286D amino acid substitutions were newly discovered.Both T123I and Y132H were identified in 26 resistant isolates,of which 16 gene mutation was detected in two pan-azole-resistant isolates.Conclusions The C.albicans strains isolated from vulvovaginal candidiasis showed higher resistance rates to azole antifumgal agents than that to 5-fluorocytosine and amphotericin B.Mutation and over-expression ofERG11 gene may be one of the prevalent molecular mechanisms underlying azole resistance in C.albicans.were pan-azole-resistant.In addition,the ERG3 heterozygous

Objective To investigate whether catestatin (bovine chromogranin A 344-364) can inhibit the biofilm formation of Candida albicans and examine its relationship with the expression of adhesion gene HWP1.Methods Clinical strains and standard strain ATCC 10231 of C.albicans were studied.XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] method was used to assess the ability of C.albicans biofilm formation.Antifungal activity against planktonic Candida ceils was evaluated in terms of minimum inhibitory concentrations (MICs) according to the description in CLSI-M27-A3.XTT assay and colony count were used to assess the effect of catestatin on inhibiting C.albicans biofilm formation.The lowest concentration showing 50 ％ inhibition on biofilm formation (BIC50) was decided by calculating the metabolic activity.The adhesion of C.albicans reduced by catestatin was visualized under an inverted microscope and quantified by colony count.The expression of HWP1 was analyzed by RT-PCR.One-way analysis of variance (ANOVA) and Dunnett's T3 test were used to compare the results.Results Clinical strains and standard strain ATCC 10231 of C.albicans showed strong ability in forming biofilm.Catestatin exhibited MICs ranging from 40 μmol/L to 80 μmol/L against planktonic C.albicans cells,and BIC50 of 80-160 μmol/L in inhibiting C.albicans biofilm formation.Catestatin reduced the adhesion of C.albicans.The colony forming unit (CFU) was 27 822.22-±-2 472.74 in blank control group,while the CFU was 5 355.55± 1 264.03,11 377.78±2 232.58,17 488.89±1 136.27,22 377.78±3 521.99,and 26 044.44±1 329.57 in the presence of 160,80,40,20,and 10 μmol/L catestatin,respectively (F=147.018,P=0.001).The difference between control group and 160,80,and 40 μmol/L catestatin was statistically significant (P＜0.05).RT-PCR found the expression of HWP1 in the presence of 160 μmol/L catestatin was about 12.24％ of that in blank control group.Conclusions Catestatin can effectively prevent C.albicans biofilm formation.This effect may be related to the down-regulated expression of adhesion gene HWP1 by catestatin,which results in reduced adhesion of C.albicans.Promising clinical prospect is expected for this finding.

Objective To understand the resistance mechanism and clinical feature of linezolid-resistant S.capitis isolated from blood samples.Methods Antimicrobial susceptibility testing was carried out to determine the susceptibility of clinical strains.PCR and sequencing analysis were used to analyze cfr gene and 23S rRNA mutation,which were associated with linezolid resistance.Patterns of pulsed-field gel electrophoresis (PFGE) were analyzed in combination with clinical data to understand the clinical feature of S.capitis strains.Results Five linezolid-resistant S.capitis strains were isolated from blood samples of 3 patients.These strains were resistant not only to linezolid,but also to most of the commonly used antimicrobial agents except glycopeptides,rifampin,and trimethoprim-sulfamethoxazole.Mutation was identified in 23S rRNA genes of all the five strains and cfr gene was found in four of the five strains.PFGE typing showed the same type,which supported the homology of the 5 strains.Three patients had deep vein indwelling catheter and two of them were treated with linezolid.Conclusions Linezolid-resistant S.capitis isolates showed the phenotype of resistance to multiple antimicrobial agents.Linezolid resistance may be mediated by cfr gene and 23S rRNA mutations in S.capitis.Long-term use of deep vein indwelling catheter and linezolid treatment may increase the risk of linezolid-resistant S.capitis infection.