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Objective To establish the in vitro biofilm model of Laribacter hongkongensis(LH),to analyze the type Ⅰ integron related genes carried by LH and to investigate the mechanism of LH resistance to quinolones.Methods The biofilm forming abilities of LH clinical isolates were determined by Giemsa staining qualitative method and by crystal violet staining semi-quantitative method.The sensitivity of LH to norfloxacin,ofloxacin,levofloxacin,ciprofloxacin and lomefloxacin in both planktonic and biofilm conditions were dectermined by broth microdilution susceptibility tests.Type I integron related genes carried in 18 LH strains resistant to quinolone were detected by PCR amplification method.Results The detection results by Giemsa staining demonstrated that 36 strains in 55 LH clinical isolates formed visible biofilm,and the biofilm formation rate was 65.4%(36/55).In the biofilm forming ability detected by crystal violet staining semi-quantitative method,OD560≤0.15 was in 8 strains of LH,0.150.20 in 7 strains respectively.The levels of minimal biofilm inhibitory concentration in norfloxacin,ofloxacin,levofloxacin,ciprofloxacin and lomefloxacin to LH were respectively higher than the minimal inhibitory concentration(MIC) in the corresponding floating bacteria(P<0.05).Among 55 strains of LH,18 strains were resistant to quinolones,the resistance rate was 32.7%,and the type I integron in 18 strains of LH carried the drug resistant genes,these drug resistant genes played the drug resistance role in corresponding bacterial strains.Conclusion Drug resistance gene formation and widespread of LH may be associated with type I integron.
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Objective To investigate the changes of drug resistance and class Ⅰ integron in clinically isolated Pseudomonas aeruginosa(PA) in our hospital form January 2013 to December 2015.Methods Clinically isolated PA strains were divided into the 3 time periods of 2013,2014 and 2015.Their resistance to 22 commonly used antibacterial drugs was investigated by adopting the VITEK-2;200 strains were randomly selected from the isolated strains during these 3 time periods.Class Ⅰ integron was detect by PCR.Results The detected PA in these 3 time periods had 366,437 and 520 strains respectively.The drug resistance of Pseudomonas aeruginosa to 22 commonly used antibacterial drugs was remarkably increased(P<0.05),especially in ICU.The detection rate of class Ⅰ integron positive bacteria was gradually increased year by year,moreover the drug resistance rate of class Ⅰ integron positive bacteria was significantly higher than that of class Ⅰ integron negative bacteria (P<0.01).Conclusion The drug resistance rate of PA in this hospital is higher.The proportions of multi-drug resistance and classⅠ integron are significantly increased.The hospital infection detection and drug-resistant bacterial monitoring should be strengthened to further standardize the use of antibacterial drugs.
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Objective To investigate the risk factors of nosocomial infection of imipenem‐resistant Acinetobacter and prevalence situation of class Ⅰ integron to provide references for preventing and controlling its nosocomial infection .Methods The strains of imipenem‐resistant Acinetobacter causing nosocomial infection were performed the drug resistance analysis and multivariate re‐search .The class Ⅰ integron gene was detected by using PCR .Results Admission to ICU ,joint use of antibacterial agents and high APACHEⅡ score were the independent risk factors of nosocomial infection induced by imipenem resistant Acinetobacter .The posi‐tive rate of class Ⅰ integron was up to 98 .6% .Conclusion The nosocomial infection of imipenem‐resistant Acinetobacter is affect‐ed by multiple factors .The class Ⅰ integron is widely prevalent in this hospital ,which is associated with the multidrug resistance of imipenem‐resistant Acinetobacter .The infection prevention measures in severe patients should be strengthened for timely finding the infection source ,protecting the susceptible populations and cutting off dissemination approach .
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Objective To evaluate the effect of azithromycin on class Ⅰ integron-integrase gene (intI 1 )mRNA expression in biofilm-forming (BF)Pseudomonas aeruginosa (PA).Methods intI 1 of 10 PA strains isolated from a hospital were detected,1 strain with positive BF+intI 1 was selected for culture,blank control group and three az-ithromycin trial groups (divided according to 3 concentrations:16 mg/L,32 mg/L,and 64 mg/L)were set,experi-ments were repeated 5 times,expression of intI 1 mRNA were detected by RT-PCR.Results Relative expression of intI 1 mRNA in azithromycin groups of 16 mg/L,32 mg/L,64 mg/L,and control group were (1 .15 ±0.04), (12.47±3.10),(19.71 ±0.78 ),and (1 .00 ±0.00),respectively,there were significant difference among four groups(F =163.82,P 0.05),but among other groups were significantly different (P <0.05 ),intI 1 mRNA expression in azithromycin groups increased with the enhancing concentration of azithromycin in culture so-lution .Conclusion Expression of intI 1 gene mRNA in BF PA can be up-regulated by the present of azithromycin, which may improve the probability of drug-resistant genes,and promote drug-resistant gene recombination.
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OBJECTIVE To explore the relationship between multidrug resistance of Acinetobacter baumannii(ABA) and its class Ⅰ integron.METHODS In this study,39 multidrug resistant strains and 41 non-multidrug resistant strains of ABA were collected.The improved Kirby-Bauer was employed to check the collected strains′ drug-resistant phenotype;PCR was administrated to detect the distribution of class Ⅰ integron.and their relationship was also analyzed.RESULTS Results showed that ABA′s drug-resistance rate to the most antibiotics was high.imipenem,cefoperazone-sulbactam,ABA was sensitive to ciprofloxacin,amikacin and Piperacillin-tazobactam,however,ABA′s drug resistance rates to other antibiotics were all over 40%.It revealed that ABA′s drug-resistance rate was high.The study indicated that the positive rate of Class Ⅰ integron in multidrug resistant ABA was as hight as 82.1%(32/39).The positive rate of non-multidrug resistant strains was 26.8%(11/41),and the differences were statistically significant(?2=24.6,P
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OBJECTIVE To study the existence status of class Ⅰ integron and transposable element of multi-resistant Acinetobactor baumannii isolated form ICU of Yinzhou People′s Hospital in Ningbo. METHODS The samples of 20 A.baumannii isolates were collected from Oct 2007 to Jul 2008.The susceptibility to 32 antibiotics of the isolates was measured.The genetic markers of integron qacE△1-sul1 and transposable element tnpU were analyzed by polymerase chain reaction(PCR).The PCR products of tnpU or qacE△1-sul1 were sequenced for determination. RESULTS In the 20 ABA isolates,the positive rate of class Ⅰ integron qacE△1-sull was 75%,and the positive rate of transposable element tnpU was 55.0%. CONCLUSIONS The positive rate of the integron qacE△1-sul1 and transposable element tnpU for multi-resistant A.baumannii is high in Yinzhou People′s Hospital in Ningbo.It should be reevaluated the preventative role of chlorhexidine for operation.