Objectives To investigate the mechanism of integron mediated resistance and multidrug-resistance in P.aeruginosa.Methods The variable region of integron was amplified by integron PCR.Restriction fragment length polymorphism(RFLP)and DNA sequencing were used to investigate the resistance genes in the variable region of integron.Results Of the 98 strains 35(35.7%)were the variable region positive,and size of the amplicons ranged from 1.0 kb to 4.0 kb.A total of 6 different cassette arrays were detected,including genes coding resistance to aminoglycosides,?-lactam compounds and sulfanilamides.Of the 5 cassette arrays 3 were novel,including aadA6-orfD,aadB-blaP1 and aadB-aac6-Ⅱ-blaCARB-8,and the Genbank numbers were DQ 091179,DQ 141316 and DQ 288251 respectively.Conclusions Integron mediates the resistance and multidrug resistance in P.aeruginosa.The majority of the genes located in integrons are those coding resistance to aminoglycosides.Three strains of class I integron with novel cassette arrays are reported.

Objective To establish a semi-quantitative method for measurement of HCV RNA by use of primers and probe, which was sensitive and designed by ourselves, a new europium fluorescent chelate BHHCT. Methods 44 serum samples of HCV infected patients and 20 samples of the healthy people were collected. HCV RNA in serum sample was extracted by HCV fluorescence PCR diagnostic kit produced by Zhongshan University DAAN Gene Co Ltd, and amplified by RT-PCR in which one PCR primer was pre-labeled with biotin. The amplified products were hybridized with capture probes pre-fixed on the microplate. The biotin in the amplified products was conjugated with europium labeled streptavidin. So europium was linked to the target DNA. Then the fluorescent of europium was measured. Results The linear range of this assay was 10 - 10 copies/ml. Both sensitivity and specificity were 100%. Conclusion Europium labeled RT-PCR assay is a sensitive, specific, fast and non-radioactive contaminant method for the measurement of HCV RNA.

n positive blood culture, and they are resistant to a variety of antimicrobial agents, which should be called attention.

Objective To investigate the resistance status of different integrons of Shigella sonnei (S.sonnei) and to analyze the distribution of resistant genes in integrons in Jiangsu Province.Methods A total of 32 strains of S.sonnei isolated from six cities of Jiangsu Province in 2011 were collected.The antibiotic susceptibility was tested by disk diffusion method.The molecular homology was analyzed by pulsed field gel electrophoresis (PFGE).The detection and classification of integrons were achieved by analyzing the positive polymerase chain reaction (PCR) products using restriction fragment length polymorphism (RFLP).RFLP and DNA sequencing were used to analyze the resistance genes in integrons.Results Multi-drug resistance (MDR) was detected in 28 (87.5％) S.sonnei strains.The resistant rates to ampicillin,nalidixic acid and tetracycline were highest (87.5％,respectively).However,it was sensitive to norfloxacin.PFGE analysis showed that there were 3 kinds of homologous clones involving 31 strains of the 32 S.sonnei strains.Among them,2,5 and 24 strains had the same clones,respectively.Accordingly,they spread within one,two and five different cities.The detection rates of class 1,class 2 and the atypical class 1 integrons in S.sonnei were 62.5％ (20/32),81.3％ (26/32) and 21.9％ (7/32),respectively,and no class 3 integron was detected.Sequence analysis of class 1 integron variable area revealed that it contained multiple resistant genes (aacA4-cmlA1 and dfrA1-aadA 1) ; dfrA1-sat 1-aadA 1 from class 2 integron and blara-30-aadA 1 from atypical class 1 integron were also identified.Conclusions In 2011,homologous S.sonnei strains spread among different cities in Jiangsu Province.MDR strains are prevalent and integrons are widespread which mediated the emergence of MDR strains.

Objective To evaluate the performance of modified Hodge test on the detection of carbapenemases among Enterobacteriaceae with decreased susceptibility to carbapenems. Methods Fortynine Enterobacteriaceae isolates with decreased susceptibility to carbapenems ( MIC of imipenem, meropenem or ertapenem was ≥ 2 μg/ml ) were collected from 16 teaching hospitals from 2004 to 2008. MICs of imipenem, meropenem and etapenem were determined by agar dilution method. Carbapenemases were detected by modified Hodge test. Carbepenemase-causing positive results and AmpCs-causing positive results were differentiated by phenyl boronic acid and oxacillin. Beta-lactamases encoding genes including blaNDM-1were detected by PCR and sequencing. Results Thirty-six of 49 isolates were non-susceptible to imipenem (MIC >4 μg/ml), 31 were non-susceptible to meropenem (MIC > 4 μg/ml) and 47 were non-susceptible to ertapenem (MIC > 2 μg/ml). Twenty-three isolates showed positive modified Hodge test result, including 9 weak-positive results and 14 strong-positive results. Through PCR detection and sequencing, 2 out of 9 isolates showing weak-positive results carried blaKPC-2 and other 7 did not carry any carbapenemase genes but AmpCs/ESBLs genes. Among the 14 isolates showing strong-positive results, 4 carried blaKPC-2, 8 carried blaIMP-4 and 2 caried blaIMP-8. All 26 isolates with negative modified Hodge test result didn't carry any carbapenemase genes. No isolate carried blaNDM-1. Carbapenemases genes PCR detection was regarded as a gold standard, and the sensitivity, specificity, positive predictive value and negative predictive value of modified hodge test was 100%, 79%, 70% and 100% on the detection of carbapenemases among Enterobacteriaceae with decreased susceptibility to carbapenems. Conclusions Modified Hodge test revealed great sensitivity but showed a few false positive results. True and false positive results can be effectively differentiated by phynel boronic acid and oxacillin.

OBJECTIVE To investigate the antimicrobial resistance of hospital-and community-acquired pathogens collected from 10 teaching hospitals located at different areas in China in 2006.METHODS According to the study protocol,the strains of Streptococcus pneumoniae,meticillin-susceptible Staphylococcus aureus(MSSA),Escherichia coli and Klebsiella pneumoniae were collected and sent to the central lab for reidentification and susceptibility testing.The minimal inhibitory concentrations(MICs) of antimicrobial agents against Str.pneumoniae were determined by Etest method and MICs of antimicrobial agents against S.aureus,E.coli and K.pneumoniae strains were determined by agar dilution method.WHONET5.4 software was used to analyze the data.RESULTS Among 353 Str.pneumoniae strains,74.2% were penicillin-susceptible(PSSP),9.6% were penicillin-intermediate(PISP) and 16.2% were penicillin-resistant(PRSP).Strains from different hospitals showed different sensitivity to penicillin.Among ?-lactam antibiotics,cefuroxime showed the lowest susceptibility rate of 0%(for PRSP) to 76.7%(for PSSP).The susceptibility rate to ceftriaxone and amoxicillin-clavulanic acid was 98.1% and 98.9% in PSSP group,61.8% and 64.7% in PISP group,and 15.8% and 10.5% in PRSP group.The ESBLs rate was 56.2% among 267 Escherichia strains and 42.7% among 206 K.pneumoniae strains.For ESBLs-producing strains,the susceptibility rates to cefotaxime and ceftriaxone were low and the rate to ceftazidime was relatively high among ?-lactam antibiotics.73.4% MSSA strains produced ?-lactamase.?-Lactam antibiotics tested showed high susceptibility against MSSA strains.The susceptibility rate was 98.9-100%.The susceptibility rate to ciprofloxacin and levofloxacin was 80.8% and 88.1%,separately.CONCLUSIONS Fluoroquinolones show high susceptibility against Str.pneumoniae.Ceftriaxone and amoxicillin-clavulanic acid have relatively high susceptibility among ?-lactams.For MSSA and non-ESBLs-producing E.coli and K.pneumoniae strains,?-lactams show high susceptibility.For ESBLs-producing E.coli and K.pneumoniae strains,the susceptibility rates to cefotaxime and ceftriaxone are low and that to ceftazidime,cefepime and cefoperazone-sulbactam are relatively high.

Objective To assess the efficacy and safety of morinidazole combined with appendectomy in treating purulent or gangrenous appendicitis.Methods Double-blind randomized controlled multicenter clinical trial was designed and conducted.Totally 437 patients were included,219 in the control group and 218 in the experimental group.Cases of purulent or gangrenous appendicitis were enrolled and assigned to each of the two groups.The control group received ornidazole injection for 5 to 7 days while the experimental group received morinidazole injection.Both groups underwent appendectomy.Clinical response,micrombiological outcomes,overall response were evaluated.Adverse events and side effects were recorded.Results No significant difference was observed between the two groups regarding the clinical healing rate at 5-10 days after medicine withdrawal,anaerobia clearance and overall healing rates.Adverse events occurred in 140 patients (32.1％).Incidence of adverse events in the control group and the experimental group was 34.7％ and 29.4％,respectively (P ＞ 0.05).The overall incidence of side effects was 15.1％ (66 cases).Side effects were less seen in the experimental group compared with that in the control group (11.5％ vs.18.7％,P ＜ 0.05).The most frequent side effects were aminotransferase rising,thrombocytosis,nausea,vomiting and electrocardiographic abnormality.Conclusions The effect of morinidazole plus operation was comparable with ornidazole in treating purulent or gangrenous appendicitis.The safety of morinidazole is better than ornidazole.

Objective To investigate antimicrobial resistance among Streptococcus pneumoniae clinically isolated from 14 teaching hospitals located at different areas in China in 2005-2008 and to give logical guidance for clinical empirical therapy.Methods A total of 1 317 non-repetitive S.pneumoniae isolates in 14 teaching hospitals from 2005-2008 were collected and sent to the central lab for reidentification and susceptibility testing, including 271 isolates collected in 2005, 391 isolates collected in 2006, 363 isolates collected in 2007 and 292 isolates collected in 2008. Most of the isolates were from community-acquired respiratory tract infections, which were isolated from outpatient or emergency department patients with respiratory tract infections or those patients with respiratory tract infections within ≤48 hours hospitalization.The districts where the organisms were isolated include North China, Northeast China, South China, Central and Northwest China and East China.The patients included adults, teenagers and children.The minimum inhibitory concentrations (MICs) or inhibitory zone diameter of 17 antimicrobial agents were determined by Etest method, agar dilution method or disk diffusion method.WHONET5.5 software was used to analyze susceptibility rate, intermediate rate, resistance rate, MIC50 and MIC90.Results Linezolid (100%) and fluoroquinolones (95.2%-99.7%) showed excellent activities against S.pneumoniae.Among β-lactams, amoxicillin-clavulanic acid remained high activities (73.8%-92.1%),followed by penicillin, ceftriaxone and cefepime with year-over-year decrease in activities.The activities of three second-generation cephalosporins were low (36.3%-38.4% in 2008).The activities of erythromycin, azithromycin, clindamycin, trimethoprim/sulfamethoxazole and tetracycline against S.pneumoniae were poor and decreased year over year.The incidence of penicillin non-susceptible S.pneumoniae (PNSP) was increasing especially for PISP (from 4.4% in 2005 to 20.2% in 2008).The incidence of PNSP in North China was low (6.0%), while this value were high in central China and East China (30.1% and 38.7%, separately).The incidence of PNSP in adults (15.7%) was obviously lower than that in children(≤5 years:33.0%) and teenagers (6-17 years:38.2%).Conclusions linezolid and fluoroquinolones showed excellent in vitro activity against S.pneumoniae, followed by penicillin and cephalosporins with year-over-year decrease of activity. Clinicians should pay more attention when using those antimicrobial agents with poor activity against S.pneumoniae, which include macrolides, clindamycin, trimethoprim/sulfamethoxazole and tetracycline.