Objective To analyse pathogens distribution and antibacterial susceptibility of bacteria isolated from clinical speci‐mens in neurosurgery ,in order to provide laboratory basis for rational use of antibacterial agents .Methods Isolation and culturing of bacteria were carried out in various clinical samples collected in neurosurgery from January 2012 to September 2012 in the First Affiliated Hospital of Xi′an Jiaotong University ,all strains were identified by using automatic microbial analyzer ,and the sensitivi‐ties to antibacterial agents were verified by using instrument method and K‐B method .WHONET5 .6 software was used for data a‐nalysis .Results A total of 1 319 strains of non‐repeating pathogenic bacteria were isolated ,including 482 strains (36 .6% ) of gram‐positive bacteria ,797 strains (60 .4% ) of gram‐negative bacteria ,and 40 strains (3 .0% ) of fungi .Most of pathogenic bacteria were isolated from sputum ,cerebrospinal fluid ,urine and blood specimens ,and the most common isolates were Staphylococcus aureus , Acinetobacter baumannii ,Klebsiella pneumoniae ,Pseudomonas aeruginosa and Escherichia coli .Isolated gram‐positive bacteria and gram‐negative bacteria were resistant to antibacterial agents in different degree .The sensitivity rate was 100 .0% only in linezolid and vancomycin against Staphylococcus aureus .The resistant rates of carbapenems against Acinetobacter baumannii were higher than 80 .0% ,and carbapenems‐resistant Klebsiella pneumoniae strains had also appeared .Carbapenems‐resistant Escherichia coli strains had not yet been found .The sensitive rate of Piperacillin‐Tazobactam against Pseudomonas aeruginosa was above 90 .0% . Conclusion Gram‐negative bacteria is the predominant pathogen infecting patients in neurosurgery ,w hile Staphylococcus aureus are the most common isolates .For the increase of multiple drug‐resistant and pan‐drug‐resistant bacteria ,clinical rational use of antibac‐terial agents for anti‐infection treatment may be very important .

Objective To explore the value of procalcitonin(PCT ) as early predictor of bloodstream infections .Methods Blood culturing and PCT detection were carried out simultaneously in 530 blood specimens collected from the First Affiliated Hospital of Xi′an Jiaotong University from January to December 2014 .All strains were identified by using automatic identification microbial an‐alyzer ,and levels of PCT were analyzed by using automatic enzyme‐linked fluorescent immune system .The diagnostic efficacy of PCT was evaluated by using the receiver operating characteristic(ROC) curve .Results A total of 77 specimens were with negative results of blood culturing ,and a total of 453 specimens were with positive results of culturing .Among those specimens with positive results of blood culturing ,there was 114 strains of gram‐positive bacteria ,306 strains of gram‐negative bacteria ,and 33 strains of fungi .ROC curve analysis showed that the area under the curve of PCT test in all pathogenic bacteria ,gram‐negative bacteria ,gram‐positive bacteria and fungi were 0 .760 ,0 .778 ,0 .741 and 0 .686 ,respectively .In maximum Youden′s indexes ,the cut off values were 0 .453 0 ,0 .683 5 ,0 .457 0 and 0 .399 5 ng/mL respectively ,and 0 .453 0 ng/mL was the threshold in diagnosis of bloodstream infec‐tion .Conclusion PCT is a good indicator for early diagnosing bloodstream infection ,and has better timeliness and higher sensitivity than blood culture .Moreover ,the diagnostic efficacy of PCT for gram‐negative bacteria bloodstream infections was better than that for gram‐positive bacteria and fungi bloodstream infections .

Objective To compare clinical Pseudomonas aeruginosa different sources of β-lactamase-resistant phenotype differences,as to provide theoretical basis for guiding clinical rational use of antibiotics.Methods Isolation of 478 strains of Pseudomonas aeruginosa were collected from clinical specimens in the First Affiliated Hospital of Xi'an Jiaotong University from January to December 2015,by VITEK 2 Compact bacteria identification and drug sensitivity analysis of advanced expert system for β-lactamase-resistant phenotype,statistical analysis of drug resistance phenotype and antibiotic resistance.Results 478 strains of Pseudomonas aeruginosa were mainly composed of phenotype 5 and phenotype 3.Sputum,drainage fluid and bile duct bile specimens of Pseudomonas aeruginosa were based on phenotype 5,accounted for 31.08％,34.71％ and 38.46％.Multiple comparison x2 were 3.893,4.071 and 5.595,There was no statistical difference between groups compare significance (P＞0.05).Urine,secretions and whole blood samples of Pseudomonas aeruginosa were phenotype 3,accounted for 34.88 ％,27.78 ％,45.45 ％;Multiple comparison x2 were 6.654,9.956 and 9.852.There was no statistical difference between groups compare significance (P＞0.05).Sputum,drainage of liquid,bile duct bile and urine,secretion,whole blood specimens respectively source of Pseudomonas aeruginosa resistant phenotype distribution of two comparative difference was statistically significant (x2 =15.056～22.050,P＜0.05).Comparing the resistance of different β-lactamase-resistant phenotypes in Pseudomonas aeruginosa isolates from different sources:the sputum specimen source in imipenem,meropenem,piperacillin and piperacillin/tazobactam had significant difference (x2 =22.225～39.025,P＜0.05).There was statistical significance in department of hepatobiliary surgery only ceftazidime and meropenem differences (x2 =21.890～22.872,P＜0.05).Conclusion The phenotypic analysis of β-lactamase-resistant phenotypes of Pseudomonas aeruginosa from different specimens was different,which provided a theoretical basis for guiding the clinical application of antibiotics and the control of nosocomial infection of Pseudomonas aeruginosa.

We investigated the pathogen of an outbreak of lung infection with unknown causes.By epidemiological analysis,we used real-time PCR,ELISA,gold dipstick,VITEK2 and MALDI-TOF-MS to identify suspicious bacteria.We made use of serum plate agglutination test to confirm the suspicious bacteria and the patient serum.We isolated 2 strains of Cryptococcus albidus from environmental samples.There has been specific agglutination between suspicious bacteria and patient serum.This pneumonia may be related to the infection of Ccryptococcus albidus.

Objective To investigate antimicrobial resistance among gram-positive cocci in China in 2008.Methods From June 2008 to December 2008,1171 consecutive and non-repetitive gram-positive cocci were collected from 12 teaching hospitals.The MICs of antibacterial agents was determined by agar dilution method.Results The prevalence of MRSA and methicillin-resistant coagulase-negative Staphylococci(MRSCoN) was 49.9%(232/465) and 74.0%(179/242),respectively.The MRSA prevalence ranged from 33.3% to 65% in different regions.About 71.1%(108/152) of Staphylococcus aureus from respiratory tract specimens,48.3%(28/58) of Staphylococcus aureus from blood samples,and 36%(68/189) of Staphylococcus aureus from the pus,wound and sterile body fluid samples were resistant to methicillin.The susceptible rates of MRSA to trimethoprim/sulfamethoxazole(SXT) and chloramphenicol were 81.5%(183/232) and 89.7%(208/232).Susceptibility to gentamicin, erythromycin, clindamycin, tetracyclines,rifampicin,and quinolones were from 3.9% to 35.0%.All Staphylococci isolates were susceptible to vancomycin,teicoplanin,and linezolid.Three vacomycin-resistant Enterococcus faecium strains were found in this study.About 96.2%(101/105) of Enterococcus faecalis and 97%(130/134) of Enterococcus faecium were susceptible to linezoild.Fifty-one out of 105 of Enterococcus faecalis(48.6%)and 101 out of 134 Enterococcus faecium(75.4%)were resistant to high concentration gentaroicin.The susceptibility of Enterococcus faecalis to all the antibiotics except for chloramphenicol and tetracycline was higher than that of Enterococcus faecium.Enterococcus faecium isolates showed a high resistant prevalence to most of antibiotics except glycopeptides and linezolid.The prevalence of PISP among 225 isolates was was 36.6%(15/41),and the prevalence of PNSSP from the other patients ranged from 15.4% to 26.6%.The susceptible rates of PSSP to cefprozil,cefuroxime and cefaclor were 67.5%(114/169),66.3%(112/169) and 61.5%(104/169),respectively.All the PISP isolates were resistant to the above three antibiotics.Teicoplanin,vancomycin and linezolid were the most active agents against Staphylococcus pneumoniae(susceptible rate,100%).About 96.9%,97.8% and 98.2% Staphylococcus pneumoniae isolates were susceptible to gatifloxacin,levofloxacin,and moxifloxacin,respectively.The susceptible rates of Staphylococcus pneumoniae to ceftriaxone,chloramphenicol and amoxicillin/clavulanic acid were 81.3%,77.3%,and 68.0%,respectively.The susceptibility of Staphylococci pneumoniae to macrolides,SXT and tetracycline ranged from 11.6% to 23.6%.Conclusions The prevalence of VRE is low in China.However,methicillin-resistance among Staphylococci isolates was high.The prevalence of PNNSP isolated from (≤)3 years children is higher than in the other age population.Teicoplanin,vancomycin,and linezolid remain high activity against Staphylococci,Enterococcus faecalis,Enterococcus faecium,and Staphylococcus pneumoniae.

Objective To investigate antimicrobial resistance among gram-positive cocci in China in 2009. Methods From June to December 2009, 1169 consecutive and non-repetitive gram-positive cocci were collected from 12 teaching hospitals at 9 cities. The minimal inhibitory concentration (MIC) of antibacterial agents was determined by agar dilution method. Results The prevalences of methicillinresistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococci (MRCoNS) were 45.3% (211/466) and 89. 5% (214/239), respectively. The isolation rate of MRSA was 33. 3%-68. 1% from different samples. All Staphylococci isolates were susceptible to vacomycin, teicoplanin and linezolid. Five point five percent (7/128) E. faecium strains were resistant to vacomycin. All E.faecalis strains were susceptible to vacomycin. About 99. 1% (108/109) of E. faecalis and E. faecium were susceptible to linezoild. The prevalence of penicillin-intermediate Streptococcus pneumoniae (PISP) was 21.6% (48/222). Only 1 (0. 5%, 1/222) Streptococcus pneumoniae strain was resistant to penicillin.Teicoplanin, vancomycin, linezolid and tigecycline were the most active agents against Streptococcus pneumoniae (susceptible rate 100% ). Conclusions The high prevalence of methicillin-resistance is among Staphylococcus strains. Different samples show a different MRSA prevalence. Teicoplanin, vancomycin and linezolid show very high activity to Staphylococci,E. faecalis, E. faecium and Streptococcus pneumoniae.

Objective To analyze the distribution of clinically isolated pathogenic bacteria in Xi′an area during 2014 and their drug resistant characteristics in order to provide the data of pathogenic bacterial drug resistance for medical pharmaceutical adminis ‐tration departments and clinical rational use of antibacterial drugs .Methods The pathogenic bacteria of nosocomial infections were cultured and isolated by using the routine method .The bacterial species was identified by using the semi‐automatic or full‐automatic bacterial identification and analysis systems .The drug susceptibility test was conducted according to CLSI standards .The data sta‐tistics and analysis were performed by using the WHONET 5 .6 software .Results 31 013 strains of pathogenic bacteria were isola‐ted in 2014 ,including 20 029 strains (64 .58% ) of Gram‐negative bacilli ,9 888 strains (31 .88% ) of Gram‐positive cocci and 1 096 strains (3 .54% ) of fungi ;the top bacteria was E .coli(20 .29% ) ,vancomycin resistant Staphylococcus aureus was not be found ;the resistance rates of Enterococcus faecium and faecalis against Vancomycin were 3 .00% ,1 .00% ,which against to linezolid was 1 .00% ;the generation rates of extended‐spectrum beta‐lactamase(ESBLs) in E .coli and Klebsiella pneumoniae were 65 .0% and 56 .0% respectively .Conclusion The important pathogenic bacteria ,including MRSA ,vancomycin resistant enterococcus ,carbapen‐em resistant Enterobacteriaceae bacteria ,pan‐drug resistant Pseudomonas aeruginosa and Acinetobacter baumannii ,in nosocomial infection should be performed the intensive monitoring and the communication with clinic should be strengthened in order to make the detection results serve the clinic well .