OBJECTIVE To investigate the ESBLs-producing isolates and their resistance and genotypes in Escherichia coli and Klebsiella in three hospitals of Wannan area.METHODS The MIC of 13 antimicrobials against 79 strains of E.coli and Klebsiella were determined by 2-fold agar dilution method.The confirmation test was used to detect ESBLs-producing strains according to CLSI 2005.PCR method was used to amplify beta-lactamases of ESBLs-producing isolates by 8 premiers,PCR products were purified and then sequencing was performed.RESULTS The ESBLs-producing rates in E.coli and Klebsiella in three hospitals of Wannan area were 61.5% and 45.0%,respectively.The resistance rates to CRO,CTX,CAZ,CIP and LEV of ESBLs-producing strains were 81.0%,81.0%,47.6%,71.4% and 50.0%,respectively,all isolates were susceptible to meropenem and imipenem.PCR indicated that CTX-M1,CTX-M13,TEM and OXA1 types of beta-lactamases were the four major genotypes of the three hospitals in Wannan area.CONCLUSIONS The isolation rates of ESBLs-producing E.coli and Klebsiella as well as their resistance rates to cephalosporins and quinolones in the three hospitals in Wannan area are quite high.Monitoring ESBLs-producing isolates should be strengthened in clinic and laboratory.

Objective To investigate the distribution and antibiotic resistance of the pathogens isolated from blood culture . Methods Identification and antimicrobial susceptibility testing were performed with MicroScan WalkAway 96 PLUS or VITEK 2 compact .WHONET 5 .6 software was used for analysis of the susceptibility data according to CLSI 2013 breakpoints .IBM SPSS 20 .0 was employed to compare the resistance rates between groups . Results Gram-positive bacteria , gram-negative bacteria and fungi accounted for 57 .8% ,36 .0% and 6 .2% of the 503 nonduplicate isolates ,respectively .The most common isolates included coagulase-negative Staphylococcus , Escherichia coli , Enterococcus spp ., Staphylococcus aureus and K lebsiella pneumoniae . The prevalence of methicillin-resistant S . aureus (MRSA ) and coagulase-negative Staphylococcus (MRSCN) was 32 .3% and 71 .7% respectively .The coagulase-negative Staphylococcus isolates from ICU patients showed higher resistance rates to many antibiotics than those non-ICU strains (P<0 .05) .E .coli and K .pneumoniae strains showed high percentage of resistance to cephalosporins , but relatively low resistance to piperacillin-tazobactam , imipenem and amikacin .A .baumannii isolates were highly resistant to most antimicrobial agents . Candida species were less resistant to antifungal agents .Conclusions The pathogens isolated from blood culture are diverse .The resistance profile is quite different among various pathogens .The distribution and antibiotic resistance should be actively monitored for the pathogens isolated from blood culture in order to facilitate the rational use of antimicrobial agents .

Objective To investigate the distribution and drug resistance of pathogens isolated from urinary tract infections.Methods A total of 6 262 midstream urine samples were collected from patients in the First Alfiliated Hospital of Anhui Medical University during April 2012 and March 2013.MicroScan WalkAway 96 Plus or Vitek 2 Compact system was applied in bacteria identification and drug sensitivity test.WHONET 5.6 was adopted to analyze drug resistance,and IBM SPSS 20.0 was applied to compare resistance rates between isolates from outpatients and hospitalized patients.Results A total of 1 426 strains were isolated,in which 370 strains were gram-positive coccus (25.9％),942 strains were gram-negative bacilli (66.1％) and 114 strains were fungi (8.0％).Escherichia coli and Klebsiella pneumoniae,Enterococcus faecium and Enterococcus faecalis were the top two among gram-negative bacilli and grampositive coccus,respectively.The prevalence of extended-spectrum β-lactamases (ESBLs)-producing Escherichia coli,Klebsiella pneumoniae and Proteus mirabilis were 60.5％,51.0％ and 30.3％,respectively; About 73.3％ of Staphylococcus aureus strains and 86.7％ of coagulase-negative Staphylococcus strains were methicillin-resistant.Candida albicans and Candida glabrata were the two most prevalent fungi in urinary tract infections,and they were sensitive to most antifungal agents.Conclusion Gram-negative bacilli,especially Escherichia coli are the most prevalent pathogen in urinary tract infections,and strains are highly resistant to most antibacterial agents,suggesting that antimicrobial resistance monitoring system is needed.

OBJECTIVE To investigate beta-lactamases production in multi-resistant Citrobacter strains isolated from the First Affiliated Hospital of Anhui Medical University.METHODS Standard agar dilution method was used to determine the minimal inhibitory concentration(MIC) of 52 clinically isolated Citrobacter strains,improved three-dimensional tests were performed to detect the ESBLs-producing,AmpC-producing and MBL-producing strains in 31 Citrobacter isolates,then beta-lactamases-encoding genes were amplified by polymerase chain reaction(PCR).RESULTS Thirty one Citrobacter strains were resistant to many beta-lactams antibiotics.Twenty four strains ESBLs-producing,3 AmpC-producing and 2 ESBLs-producing plus AmpC-producing strains have been detected by improved three-dimensional tests,and not found MBL-producing ones.Twenty strains had blaTEM gene and 1 strain had blaSHV gene,8 strains had blaCTX-M-1 gene,15 strains had blaCTX-M-13 gene and 5 strains had blaCIT gene by PCR.CONCLUSIONS Multi-resistant Citrobacter strains produce one or more types of ESBLs and AmpC beta-lactamase,it may be an important reason of resistance to beta-lactams antibiotics.

OBJECTIVE To investigate the antibiotical resistance and to understand the phenotype and genotype of metallo-?-lactamase in Chryseobacterium indologenes.METHODS The MIC to 25 C.!indologenes strains was detected by agar dilution method.Phenotype of metallo-?-lactamase was detected by three-disc synergy test and modified three dimension test.Polymerase chain reaction(PCR)amplification for both metallo?-lactamase and integrase gene was conducted for all isolates.Complete coding gene of metallo-?-lactamase and their DNA sequence analysis was conducted.Conjugation experiment was used to study the transmission of metallo-?-lactamase encoding gene.pIs Of ?-lactamase was measured by isoelectric focusing assay.RESULTS The antibiotical resistance of C.indologenes to imipenem and meropenem was 88.0%,respectively.However,gatifloxacin,levofloxacin and rifampin had better antimicrobiotial ability to C.indologenes compared with other antibiotics in MIC Nineteen strains were identified to produce metallo-?-lactamase using three-disc synergy test and modified three dimension test.Twenty strains were detected to have metallo-?-lactamase genotype by PCR amplification using IND-like common prime sets and four prime sets of complete coding gene.Among them,9 strains were detected to have blaIND-1 genotype and 10 strains to have blaIND-2 genotype,strain CI-25 was identified to have blaIND-like genotype.The mutation of base sequences and amino acid sequences in 5 strains were found simultaneously.Conjugation experiment showed that metallo-?-lactamase encoding gene couldn′t transfer.Nineteen strains had 1 or 2 bands on isoelectric focusing electrophoresis.Strain CI-5 was proved to have blaIND-1,but phenotype of metallo-?-lactamase was negative.CONCLUSIONS C.indologenes has high rate of metallo-?-lactamase producing,and thus it is difficult to treat.The major genotype of metallo-?-lactamase for C.indologenes is blaIND-1 and blaIND-2 in Hefei.The expression of blaIND could exist negative or low level occasionally.

Objective To investigate the clinical features and prognostic factors of nosocomially acquired candidemia.Methods A retrospective analysis was conducted for hospitalized patients with nosocomial candidemia between January 2012 and December 2014 at the First Affiliated Hospital of Anhui Medical University.The univariate and multivariate Logistic regression analyses were used to determine the prognostic factors of candidemia.Results A total of 92 patients were diagnosed with nosocomially acquired candidemia.The most common pathogen was Candida glabrata (C.glabrata,39/92,42.4％),followed by Candida albicans (C.albicans,30/92,32.6％),then Candida krusei (C.krusei,7/92,7.6％),Candida tropicalis (C.tropicalis,5/92,5.4％),Candida parapsilosis (C.parapsilosis,4/92,4.4％) and other Candida spp.(7/92,7.6％).The sensitivity rates of Candida spp.strains against flucytosine,amphotericin B,voriconazole,fluconazole and itraconazol were 100.0％,98.9％,92.4％,82.6％oo and 77.2％,respectively.The 30-day attributable case fatality rate was 13.0％(12/92).Multivariate Logistic regression analyses indicated that presence of central venous catheter (OR=4.833,95％CI:1.010-23.125,P=0.049),invasive mechanical ventilation (OR=6.075,95％CI:1.144-32.257,P=0.034),and receiving hemodialysis (OR =8.367,95 ％ CI:1.390-50.364,P =0.020)were factors independently correlated with increased mortality.Conclusions The pathogens causing nosocomially acquired candidemia are mainly C.glabrata,C.albicans and C.krusei.The drug susceptibility of Candida spp.varies among fluconazole,itraconazol voriconazole.The resistant rates of Candida spp.against voriconazole,fluconazole and itraconazol are different.The presence of central venous catheter,invasive mechanical ventilation and receiving hemodialysis are factors independently correlated with increased mortality.