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Objective To investigate the trend of antimicrobial resistance and the prevalence of resistant genes in Pseudomonas aeruginosa strains isolated from Hangzhou First People's Hospital.Methods Antimicrobial susceptibilities of 1489 Pseudomonas aeruginosa strains isolated from 2003 to 2007 were statistically analyzed using WHONET.MICs of 11 antimicrobisis to 36 multi-drug-resistant Pseudomonas aerugionosa strains were determined by agar dilution method.Genes of β-lactamases(BLA)and aminoglycoside-modifying enzymes(AMEs)were detected by PCR and the PCR products were sequenced.Results The resistant rates to aztreonam,imipenem,ceftazidime,cefepime,piperacillin,piperacillin/tazobactam.cefoperazone/sulbactam,ciprofloxacin,levofloxacin,gentamicin and amikacin were increased from 13.4%,10.6%,8.7%,7.9%,12.7%,12.7%,6.7%, 15.8%,20.5%,24.7% and 10.9%in 2003 to 35.3%,40.9%,18.4%, 32.4%,32.9%,32.0%,21.9%,37.8%,38.6%, 39.4% and 34.8% in 2007.respectively.Hish MICs of 11 antimicrobiMs for multi-drug resistant Pseudomonas aerouginosa were determined with MIC90≥128 μg/mL.In 36 multi-drug resistant Pseudomonas aeruginosa strains,21(58.3%)strains carried β-lactamase genes and 32 strains(88.9%)carried aminoglycosidemodifying enzyme genes,while the deletion rate of oprD2 was 80.6%(29/36).Conclusions The resistant rates to common antibiotics of Pseudomonas aeruginosa have increased.resulting in multi-drug resistance.Genes of β-lactamases and aminoglycoside-medifying enzymes are prevalent in multi-drug resistant Pseudomonas aeruginosa strains,with the common deletion of oprD2.
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OBJECTIVE To investigate the rate of the clinical isolation of ESBLs positive Escherichia coli and the resistance in intensive care units(ICU).METHODS We isolated E.coli from 2003 to 2004 in our hospital ICU,phenotypic confirmatory test was applied to detect ESBLs.Bacterial drug susceptibility test was performed by standard Kirby-Bauer method.RESULTS The isolation rate of ESBLs positive E.coli was 74.36% in 2003 and 81.58% in 2004.ESBLs positive bacteria had high resistance to antibacterial drugs,but the resistance rate did not rise.ESBLs negative bacteria were more susceptible to antibacterial drugs(P=0.001);but ESBLs negative bacteria in 2004 had higher resistance than in 2003(?2=84.511,P=0.001).CONCLUSIONS It is very important for ICU to use ESBLs detection test in time,and antibacterial drugs in reason.
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OBJECTIVE To investigate the resistance and the distribution of the main ?-lactamases encoding gene in Acinetobacter baumannii isolated from four hospitals in Hangzhou city to provide the basic data for the optional treatment of A.baumannii infection.METHODS The identification of A.baumannii was performed using VITEK-AMS60.The minimum inhibitory concentrations(MIC) was examined by agar dilution and E-test.The homology of the resistant isolates was finished by pulsed field gel electrophoresis(PFGE).PCR and sequencing were used to analyze the ?-lactamases encoding gene of the 36 strains of imipenem-resistant A.baumannii.RESULTS All of the imipenem-resistant isolates produced carbapenemase OXA-23,and 5 isolates produced PER-1,2 isolates produced TEM-1 except OXA-23.No metallo-?-lactamases were detected.No plasmid was extracted.Clone transmission of the imipenem-resistant strains existed in the 4 hospitals.Most strains were isolated from intensive care unit(ICU). CONCLUSIONS The clone transmission of imipenem-resistant A.baumannii strains is occurred in 4 hospitals.All strains produce carbapenemase OXA-23.Five strains also produce PER-1 type extended-spectrum ?-lactamases.Two strains also produce TEM-1 type extended-spectrum ?-lactamases.
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OBJECTIVE To investigate the distribution and the antimicrobial resistance of Alcaligenes xylosoxidans and to provide the guidance of rational use of antibiotics.METHODS A.xylosoxidans was isolated and identified through VITEK-AMS all-automatic microbiology analysis system and its G~-bacilli identification cards(GNI) and drug sensitivity cards(GNS-KI/121) were also analyzed.Drug-resistance was tested by Kirby-Bauer disk(sensitivity) method((Bio-Merieux) and Oxoid products).RESULTS The drug-resistance rates to the 1st to 4th((except) CAZ) generation cephalosporins were more than 77%.The drug-resistance rate to the aminoglycosides was more than 76%,and to(ampicillin,) amoxicillin/CA,ampicillin/sulbactam,cefoxitin and cefuroxime were all 100%;but to(aztreonam) was 92.86%;66.67% and 44.44% strains were resistant to ciprofloxacin and(levofloxacin).(CONCLUSIONS) The detection rates of the multidrug resistant A.xylosoxidans have the tendency to increase yearly.The antibiotics should be used reasonably according to the results of drug sensitivity test in clinic.
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Objective To explore the antibacterial activity of the baicalin injection in vitro.Methods The broth doubling dilution method has been adopted.And the minimal inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of baicalin injection on 161 common pathogenic bacteria obtained from clinical practice were determined.Results The MIC range of baicalin against clinically common pathogenic bacteria is 0.1～50mg/ml and the MBC range is 0.2～50mg/ml.The MIC and MBC against staphylococci is remarkably lower than those against other bacteria,with the MIC range of 0.1～6.3mg/ml and MBC range of 0.2～12.5 respectivel.The MIC50,MIC90 are respectively 0.4mg/ml and 0.8mg/ml.Conclusions The baicalin injection possesses various levels of inhibitory effect on manifold pathogenic bacteria,especially the antibacterial effect on the staphylococci.
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OBJECTIVE To investigate the distribution of pathogens and their antibiotic resistance in lower respiratory tract infection(LRTI) from intensive care unit(ICU) in our hospital,and provide basis for rational selection of clinical drugs.METHODS Pathogens were detected from qualified sputum specimens in LRTI from ICU and identified by VITEK-AMS60 automatic microbial analyzing system.Drug susceptibility was determined by KB test.RESULTS From 320 sputum specimens 367 pathogens were detected between from Jan 2007 to Mar 2008,including 261 strains(71.1%) of Gram-negative bacilli,70 strains(19.1%) of fungi,and 36 strains(9.8%) of Gram-positive cocci.21.8% Of the isolated pathogens were Acinetobacter baumannii,with 16.7% of drug-resistant rate to cefoperazone/sulbactam and over 71% to other 13 antibiotic agents.The rate of extended spectrum ?-lactamases(ESBLs) producing Escherichia coli isolates and Klebsiella pneumoniae ones were 65.2% and 72.0%,respectively,comparing to 84.6% for meticillin-resistant Staphylococcus aureus(MRSA).CONCLUSIONS Gram-negative bacilli are the major pathogens of LRTI in ICU,in which A.baumannii shows with a high rate of drug-resistance,followed by fungi,which should attract the clinician′s more attention.
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Objectives To investigate the properties and distributions of ampC gene among different drug-resistant strains of Serratia marcescens,and the relationship of control gene ampR with AmpC enzymes′ expressions.Methods According to the results of inducting experiment with 1/2 MIC of beta-lactam antibiotics (CTX),three-dimensional testing and isoelectric focusing electrophoresis testing,143 strains of S.marcescens were classified into three groups:including induction group, continuous low-production group and hyperproduction group. In each group, the sequences of ampC and ampR genes were amplified using the method of PCR. The products of PCR were analyzed. The plasmid-mediated beta-lactamases were detected using the method of conjugation experiment.Results Among 143 strains of S.marcescens, the continuous low -production strains, induction strains and hyperproduction strains were 14,103,and 18, respectively.125 and 99 strains were ampC and ampR gene positive, respectively.The detection rate of ampR in hyperproduction group was lower than other groups.5 sites of ampC genes and 4 sites in the Open Reading Frame (ORF) of ampR gene were easily mutated in 5 induction strains and 2 hyperproduction strains.Conclusions The production of inducing drug-resistance of some S.marcescens might be related to mutation of ampC gene encoding AmpC beta-lactamases and the ORF mutation in ampR. The continuous hyperproduction drug-resistance had something to do with deletion mutation in ampR in segmental hyperproduction strains.The plasmid-mediated AmpC enzymes hadn′t been found in S.marcescens.