Objective To investigate the genotypes and epidemic of metallo-β-lactamase-(MBL )-producing Pseudomonas aeruginosa (P .aeruginosa)in Changsha.Methods P .aeruginosa isolated from seven comprehensive hospitals in Changsha were collected and performed identification and antimicrobial susceptibility testing,pheno-types of MBL were detected with EDTA-disk synergy test and E-test,genotypes were determined by polymerase chain reaction (PCR),homology analysis were conducted by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR).Results Preliminary screening by EDTA-disk synergy test and E-test showed that only 10 of 81 iso-lates were strong positive;PCR result showed that 18 isolates were positive for MBL,11 of which were IMP-9-type MBL,1 was IMP-1-type,and 6 were VIM-2-type.SIM,SPM,GIM,and NDM-1-types were not found.ERIC-PCR showed that 12 strains of IMP-producing P .aeruginosa has multiple types,6 VIM-2-producing strains were of the same type.Conclusion IMP-9 and VIM-2 are main genotypes in P .aeruginosa in Changsha.

Objective To study the relationship between the expression of mtrF gene and high-level multiple resistant Neisseria gonorrhoea.Methods ① The susceptibility of 58 clinical Neisseria gonorrhoeae to 5 kinds of antibiotic agents was tested by disc diffusion method.② The minimum inhibitory concentration(MIC) of erythromycin was determined by tube dilution method.③ The expression of mtrD and mtrF gene in susceptive group,inter-mediated resistant group and high-level multiple resistant group was detected by semi-quantitative RT-PCR.Results ① There were 30 strains presenting resistance to two or more than two antimicrobial agents,which accounted for 51.7% of the 58 clinical strains.② The number of strains sensitive,intermediate and resistant to erythromycin was 7,21 and 30,respectively,and there were 17 strains with erythromycin MIC≥32.0 ?g /mL.③ Compared with that in susceptive group and inter-mediated resistant group,mtrF expression was up-regulated in high-level multiple resistant group(P

Objective To investigate the impact of functional enhancement of efflux pump system and reduced permeability of outer membrane on high-level multiple resistant Neisseria gonorrhoeae.Methods Several high-level multiple resistant isolates with erythromycin MIC=128.0 mg/L,accompanied by concurrent resistance to several antimicrobial agents,were selected.13 bp inverted sequence positioned within the mtrR promoter region were amplified by PCR and directly sequenced to detect the possible gene change.The outer membrane proteins of the strains were extracted to analyze the constitutive profiles by SDS-PAGE.Results There were no gene mutations in 5 sensitive strains.All the 3 high-level multiple resistant strains contained the same mutation and exhibited a single A/T base pair deletion in 13 bp inverted sequence positioned within the mtrR promoter region.Meanwhile porin protein 31 ku deficiency was found in all the 3 resistant strains.Conclusion The functional enhancement of efflux pump system induced by a single A/T base pair deletion in 13 bp inverted sequence positioned within the mtrR promoter region and the decreased cell envelope permeability induced by the absence of porin protein may have some effect on mediating high-level multiple resistance in Neisseria gonorrhoeae.

OBJECTIVE To acquire the information about the gene type and epidemic condition of the hospital to provide scientific proof for monitoring and controlling nosocomial infection.METHODS Meticillin-resistant Staphylococcus aureus(MRSA) was identified by its resistance to cefoxitin of disk diffusion and mecA PCR,randomly amplified polymorphic DNA(RAPD) was carried out with the optimization condition.RESULTS The rate of MRSA infection was 72.15% and the main gene type was A in the hospital.CONCLUSIONS The nosocomial infection may exist in the hospital and the hospital must take effective measure to decline nosocomial infection of the MRSA;RAPD is suitable for molecular epidemiology with high powerful discrimination,simplicity and rapidness.

OBJECTIVE To investigate the drug resistance and the prevalence of inducible clindamycin resistance in clinical isolates of Staphylococcus aureus and evaluate the clinical value of cefoxitin disk diffusion method and oxacillin disk diffusion for detection of meticillin-resistant S.aureus(MRSA).METHODS Bacteria identification and susceptibility test were performed by VITEK-2 system and K-B disk method.The PBP2a was detected by latex agglutination and MRSA was identified by cefoxitin disk diffusion method and oxacillin disk diffusion.The inducible resistance of erythromycin to clindamycin was checked by D-test according to the standards of CLSI(NCCLS).The statistical analysis was performed by WHONET 5.4 and SPSS 13.0 software.RESULTS Resistant rate to penicillin and ampicillin was 98.9% and 100.0%,respectively.Vancomycin-resistant(VRE) or intermediate strains were not found.Of the 93 S.aureus isolates,MRSA and meticillin-sensitive S.aureus(MSSA) were 58(62.4%) and 35(37.6%),respectively.The resistant rate of MRSA to 11 antibiotics was higher than MSSA.The sensitivity and specificity of cefoxitin disk diffusion method were 98.3% and 97.1%,respectively,those of oxacillin disk diffusion were 75.9% and 94.3%.Of the 9 isolates resitant to erythromycin but susceptible to clindamycin,5(55.6%) showed inducible resistance to clindamycin.CONCLUSIONS Resistance of S.aureus is quite serious.Cefoxitin disc diffusion method is a simple and reliable method for the detection of MRSA.The inducible resistance of erythromycin to clindamycin in S aureus should be checked by D-test in clinical microbiology laboratory routinely.

spectrum beta-lactamase genes:blaOXA-128 and blaOXA-129.

Objective To investigate the genotype distribution of CTX-M-type extended-spectrum β-1actamase(ESBLs) by denaturing high-performance liquid chromatography(DHPLC) in Hunan Province and the accuracy of DHPLC assay. Methods The blaCTX-M genes of standard strains and clinical ESBLs-producing Enterobacteriaceae were amplified by multiplex PCR followed by DHPLC and genotype determination. 25 isolates randomly selected were sequenced to assess the accuracy of DHPLC method. Results Among 142 ESBLs-producing isolates, 109 isolates carried blaCTX-M gene (76. 8% ). Four different CTX-M genotypes were detected by DHPLC, including CTX-M-3 (33 isolates), CTX-M-15 (19 isolates), CTX-M-14 (52 isolates) and CTX-M-9 (5 isolates). The DHPLC typing of 25 isolates suggested that 24 isolates were verified uniformly by the sequencing, but one CTX-M-15 isolate typed by DHPLC was shown to be CTX-M-82 by sequencing. Conclusion DHPLC is a powerful tool for genotyping of the resistance gene and is worth being applied in the clinical and scientific research with accurate, rapid and economic advantages.

Objective To observe the characteristic of precancerous lesions and early gastric carcinoma with narrow belt imaging technology. Methods The 74 patients were enrolled in this study. The same case was used as self-control. The operation was made in pain-less under anesthesia. When the mirror was advanced to the duodenal descending segment, an ordinary microscope mode was used and the mirror was back to Mallory, the lesions found were recorded, the image was zoomed in with low-fold and observed (1.4,1.6,1.8 times). Suspicious lesions were collected and biopsies were made. Results Chronic gastritis could be commonly found in type A and AB. Mild in-testinalization and mild atypical hyperplasia could be commonly found in mixed type holding type C, type BC and AB. Moderate atypical hy-perplasia could be found in type CD and AC, and heavy atypical hyperplasia in type CD and D. Early gastric cancers (superficial depressed) were seen in type BC and irregular thick type A. Advanced gastric cancers were in type CD, D and C. Helicobacter pylori infection were common in type A and B. Protruded type, sunken type were not easily missed with common endoscopic and NBI. But "for ordinary focus of infection, it was easily missed with common endoscopic, while less with NBI. Conclusion NBI is a simple and safe method, which can be used to find precancerous lesions and early gastric cancer lesions more easily. It will enlaance the diagnosis rate of precancerous lesions and early gastric cancer as positive rate of biopsy was markedly improved.

Objective To investigate the distribution and change in antimicrobial resistance of pathogens causing blood-stream infection,so as to provide reference for rational antimicrobial use.Methods The isolation and antimicrobial resistance of major pathogens from blood culture specimens from a tertiary first-class hospital in 2012-2015 were analyzed statistically.Results A total of 4 780 isolates were detected,the top five species were Escherichia coli (n = 1 008, 21.09%),Klebsiella pneumoniae (n = 624,13.05%),Acinetobacter baumannii (n = 452,9.46%),Staphylococcus aureus (n=437,9.14%),and Pseudomonas aeruginosa (n=247,5.17%).The percentage of gram-negative bacilli, gram-positive cocci,fungi,and others were 62.05%,29.31%,7.76%,and 0.88% respectively.The resistance rates of Klebsiella pneumoniae to ertapenem and imipenem increased from 4.50% in 2012 to 46.79% and 33.94% in 2015(both P<0.01).The resistance rates of Acinetobacter baumannii to cefepime,ceftazidime,tobramycin,gentamicin,and imipenem were 86.50%,80.56%,78.10%,79.87%,and 84.29% respectively;resistance rates to amikacin in 2012-2015 were 0, 10.22%,39.85%,and 21.30% respectively(P<0.01);resistance rates to minocycline in four years were 0-7.52% (P<0.01 ).Conclusion The main pathogens causing bloodstream infection are gram-negative bacilli,Acinetobacter baumannii is highly resistant to cephalosporins and carbapenems,resistance rates of Klebsiella pneumoniae to carbapenems increased rapidly.Broad-spectrum antimicrobial agents must be used cautiously to reduce the selective pressure of antimicrobial agents.

Objective To understand clinical distribution and antimicrobial resistance of clinically isolated Serratia marcescens(S .marcescens ),and provide basis for rational use of antimicrobial agents,as well as prevention and control of infection.Methods 427 S .marcescens strains isolated between January 1 ,2012 and December 31 ,2015 were analyzed,antimicrobial susceptibility testing were performed by disk diffusion method.Results 427 S . marcescens strains were mainly from respiratory tract (70.26%),among which the majority were from sputum (64.87%).S .marcescens were primarily from intensive care unit(ICU,19.44%),department of integrated tradi-tional Chinese and Western medicine(15.46%)as well as rehabilitation department (13.58%).The resistance rates of S .marcescens to cefoperazone/sulbactam,ertapenem,cefepime,ceftazidime,amikacin,imipenem,levofloxacin, and piperacillin/tazobactam were all<10%;resistance rates to ciprofloxacin,gentamicin,tobramycin,ceftriaxone, sulfamethoxazole/trimethoprim (SMZ/TMP),and aztreonam were 10%-30%.Difference in the resistance rates of S .marcescens to cefoperazone/sulbactam,ciprofloxacin,ceftriaxone,amikacin,aztreonam,and SMZ/TMP dur-ing 4 years were statistically significant (P <0.05).In 2012-2013,resistance rates of S .marcescens to cefopera-zone/sulbactam,ciprofloxacin,ceftriaxone,aztreonam,and SMZ/TMP increased obviously,then resistance rates tend to be stable,while resistance rates to cefoperazone/sulbactam decreased.Conclusion Susceptibility of S.marcescens to most antimicrobial agents are high,but resistance had increasing tendency;susceptible rates of S .marcescens to ertapenem,ceftazidime,levofloxacin,and piperacillin/tazobactam are all high,and can be used as the empirical medication for the treatment of related infection.