Objective To study the risk factors for catheter-related bloodstream infection (CRBSI)in an intensive care unit (ICU),and provide scientific evidence for CRBSI prevention and control.Methods 1 677 ICU patients with central venous catheterization (CVC)for>48 hours between January 2008 and December 2012 were divided in-to CRBSI group and non-CRBSI group,risk factors for CRBSI were analyzed.Results The utilization rate of CVC was 92.88% (21 041 d);86 (5.13%)patients developed CRBSI,the incidence of CRBSI per 1 000 catheterization-day was 4.02,the mortality of CRBSI group was significantly higher than non-CRBSI group (58.14% [50/86]vs 36.83%[586/1 591])(χ2 =15.74,P <0.01 ).Multivariate logistic regression analysis showed that the risk factors for CRBSI in-cluded length of stay in ICU>5 days,CVC>5 days,the episode of CVC>1 (P <0.01).Conclusion Realizing the occur-rence status and risk factors of CRBSI in ICU patients can provide reference for further targeted monitor and implementation of zero tolerance goal of the CRBSI.

Objective To understand the occurrence and risk factors of healthcare-associated infection(HAI) in a neonatal intensive care unit(NICU).Methods Neonates who were admitted to the NICU of a hospital from January 2012 to December 2014 were investigated retrospectively,risk factors for HAI were performed univariate analysis.Results A total of 760 neonates were included in the investigation,198 neonates developed 259 times of HAI,incidence of HAI was 26.05％,case incidence of HAI was 34.08％,incidence of HAI per 1 000 patient days was 9.50‰;the main infection site was lower respiratory tract (n =92,35.52％);among 259 cases of HAI,172 strains of pathogenic bacteria were isolated,the major pathogen was Acinetobacter spp.(n =40,23.26％);incidence of HAI was high in neonates with gestational age ≤32 weeks,birth weight≤1 500 g,length of hospital stay ≥10 days,duration of antimicrobial use≥10 days,mechanical ventilation,deep venous catheterization,and feeding intolerance,difference was statistically significant (all P＜0.001).Conclusion Incidence of HAI in NICU is high,effective prevention and control measures should be formulated according to its risk factors,so as to reduce the occurrence of HAI in neonates.

Objective To investigate the influence of health care workers’(HCWs)hand hygiene intervention in healthcare-associated infection(HAI)in an intensive care unit(ICU).Methods Intervention measures of hand hygiene were adopted,effective supervision and management systems were established,hand hygiene compliance and HAI rate be-fore intervention(January-December 2012)and after intervention (the first stage:January-June 2013;the second stage:Ju-ly-December 2013)were compared.Results A total of 4 066 patients were surveyed,HCWs’hand hygiene compliance rate before intervention was 50.03%,the first and second stage after intervention was 61.80% and 64.57% respectively,there was increasing trend (rs=1.00,P<0.001).HAI before intervention was 5.48%,the first and second stage after inter-vention was 3.86% and 3.30% respectively,there was decreasing trend (rs=-1.00,P<0.001).Significant decreasing trends were found in rates of catheter-related bloodstream infection(CRBSI),catheter-associated urinary tract infection (CAUTI)and ventilator-associated pneumonia(VAP)(rs=-1.00,P<0.001).There were negative correlations between hand hygiene compliance rate and the infection rate of ICU,infection rate of CRBSI,CAUTI and VAP (P<0.05 ). Conclusion The improvement of hand hygiene compliance can effectively reduce the incidence of HAI in ICU ward.

OBJECTIVE To type the genes of plasmid DNA in 54 clinical Klebsiella pneumoniae isolates producing extended -spectrum beta-lactamases (SHV) by denaturing high-performance liquid chromatography (DHPLc) and evaluate their sensitivity and specificity, and explore a rapid and convenient method for detecting the antibiotic resistance of K. pneumoniae. METHODS Plasmid DNA from each extended-spectrum beta-lactamase (SHV) producing strain was subjected to PCR amplification. After we performed DNA sequencing of these amplicons and identification of mutation and their genotype, DHPLc was undertaken to investigate whether its results correlate the distinctive chromatogram with each genotype. RESULTS All the strains were found abnormal elution peaks (two or three peaks) which were different from each other. The result of DNA sequencing demonstrated that all the strains had DNA mutation in comparison with SHV-1. Moreover, DHPLc could produce specific peak patterns that correlate with genotype. CONCLUSIONS The sensitivity of DHPLc is 100% in this study. And each genotype is corresponded to specific peak pattern. So we can use DHPLc technique to type the genes of plasmid DNA in K. pneumoniae and detect mutations rapidly. DHPLc not only has high accuracy , but also is a convenient and rapid technique for the detection of mutation in the bacterial genome. It has a great potential clinical value.

Objective To investigate the application of combined detection of three serum markers,anti-cyclic citrullinated peptide antibody (anti-CCP),rheumatoid factor (RF),anti-keratin antibodies (AKA),for the diagnosis of rheumatoid arthritis.Methods This was a prospective study.Serum samples were randomly obtained from 137 RA patients,265 other autoinmmune diease patients,and 111 normal controls.All of the volunteers were outpatients or inpatients of Peking University Third Hospital from January 2011 to September 2013.Levels of AKA,anti-CCP antibody,RF were measured by indirect immunofluorescence,chemiluminescence,and immune turbidimetry,respectively.The values of 3 serum biomarkers and their varied combinations for RA diagnosis were systemically assessed.The results were compared using fourfold table chi-square (x2) test.Results When using one serum marker,anti-CCP had the highest accuracy (80.39％),Youden's index (YI) (0.51),and Kappa (κ) value (0.55) for the diagnosis of RA.While using three serum markers,anti-CCP + (AKA/RF),AKA /(anti-CCP + RF),anti-CCP/(AKA + RF) and (AKA + RF)/(anti-CCP + RF)/(AKA + anti-CCP) had the highest accuracy (80.94,80.94,80.66),YI (0.51,0.51,0.50),and κ value (0.55,0.56,0.54).Conclusion AntiCCP is the vital marker for RA diagnosis.Anti-CCP + (AKA/RF),AKA/(anti-CCP + RF),and (AKA +RF)/(anti-CCP + RF)/(AKA + anti-CCP) are the most ideal combinations for RA diagnosis.

Objective To study the prevalence and sequence homology of virulence genes exoU and exoS in 53 strains of pan-drug-resistant Pseudomonas aeruginosa .Methods The virulence genes exoU and exoS were detected by PCR.Sequence homo-logy was analyzed by BOX-PCR.Results Of the 53 clinical isolates of pandrug-resistant Pseudomonas aeruginosa ,the exoS+/exoU- genotype was identified in 40 strains,exoU+/exoS - genotype in 10 strains,exoS +/exoU+ genotype in 1 strain, and exoS-/exoU- genotype in 2 strains.BOX-PCR results showed that 41 exoS+ isolates belonged to 24 genotypes,and 11 exoU+ strains could be grouped into 7 genotypes.Conclusions The prevalence of virulence genes is high in clinical isolates of pandrug-resistant Pseudomonas aeruginosa .BOX-PCR fingerprint analysis combined with sequence homology analysis is help-ful for effective monitoring and control of hospital pandrug-resistant pseudomonas aeruginosa infection.

Objective To investigate the resistance and ?-lactamase of cefoxitin-resistant Klebsiella pneumoniae. Methods The minimal inhibitory concentrations were determined by standard agar dilution.Isoelectric focusing was used to measure the PI(s) of an isolate,s ?-lactamase,AmpC and ESBLs activity was confirmed by a three-dimensional extract method. Results The resistant rates of 40 strains were as follows: imipenem and meropenem 0.0%,cefepime 20.6%,cefotaxime(22.5%),ceftazidime 60.0%.The most isolates were demonstrated two or more ?-lactamase bands by IEF.Of 39 strains tested,ESBLs was detected in 31(70.5%) strains and AmpC-type?-lactamase in 16(41.0%) strains by three dimensional extract test. Conclusions These cefoxitin-resistant Klebsiella pneumoniae produced two or more ?-lactamases.It is imperative for clinical microbiology laboratories to detect and research ?-lactamases,especially AmpC enzyme.

We developed a microfluidic device to integrate sample introduction, bacteria culturing and results reading. The identification of multiple bacteria was achieved by combining the spatial resolution of the arrayed bacteria culture chambers and the color resolution benefited from the bacteria specific chromogenic media. A set of 4 common pathogenic bacteria responsible for urinary tract infection were used as a model to test the microfluidic assay. Our results showed that the bacteria identification assay can be completed in 15 h, with a limit of detection (LOD) of bacteria density down to 10 cfu / mL. Clinical sample testing using the microchip approach showed a coincidence rate of 96. 3% as compared with the conventional method. The developed microfluidic approach is simple and rapid, thus hold the potential to serve as a powerful tool for detection of multiple bacteria.

OBJECTIVE To understand characteristics of TEM-116 ?-lactamases through comparative study on resistance to antibiotics of clinical isolates of Klebsiella pneumoniae producing TEM-116 ?-lactamases.METHODS K.pneumoniae susceptibility to ?-lactamases was determined by disk diffusion tests,and their isoelectric points(PI) were detected using analytic isoelectric focusing(IEF),and resistance to antibiotics of clinical isolates of K.pneumoniae producing TEM-116 and TEM-1?-lactamases was studied.RESULTS Both of K.pneumoniae producing TEM-116 ?-lactamases and producing TEM-1 ?-lactamases were 100% resistant to AMP,and highly resistant to the first and second generation cephalosporin,but greatly susceptible to FEP and IPM.There was greatly difference between resistance to AMC,TZP,AMK,and GEN of clinical isolates of K.pneumoniae producing TEM-116 ?-lactamases and that of K.pneumoniae producing TEM-116 ?-lactamases,the TEM-116 isolates were higher resistant than TEM-1 isolates.Analytic IEF results showed that PI of TEM-116 ?-lactamases was 5.4,and most strains of K.pneumoniae TEM-116 ?-lactamases displayed two electrophoresis bands or more,only one strain of them just displayed one band,resistant to majority of antibiotics.CONCLUSIONS The results show that K.pneumoniae producing TEM-116 ?-lactamases are more resistant to antibiotics than K.pneumoniae producing TEM-1 ?-lactamases,and indicate TEM-116 ?-lactamases work as ESBLs.

Objective To investigate the prevalence of 16S rRNA methylase genes in Klebsiella pneumoniae isolates from Guangzhou.Methods K-B test was used to determine the resistant rates of these stains.Five 16S rRNA methylase genes,armA,rmtA,rmtB,rmtC,and rmtD,were detected by PCR.Results All 55 K.pneumoniae isolates showed resistant to arbekacin,gentamicin,tobramycin,and neomycin.Susceptibility rates were 5.5%,20.0%,72.7%,and 100% to ceftazidime,ciprofloxacin,piperacillin/tazobactam,and imipenem respectively.ESBLs were positive in 52 of 55 (94.5%) isolates.Among 55 K.pneumoniae isolates,34 were positive for armA and 1 for rmtB.Conclusions In K.pneumoniae resistant to arbekacin,the positive rate of 16S rRNA methylase genes was high,predominantly with armA positive.These strains were highly resistant to some antibiotics.