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Objective To investigate the expressions of aminoglycoside modifying enzymes (AMEs)genes of extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) isolates in our hospital, with an attempt to provide evidence for rational clinical antibiotics use. Mothods A total of 42 strains of ESBL-KP were isolated from January 2007 to January 2008 in our hospital The expressions of 9 AMEs including aac (3)-Ⅰ , aac (3)-Ⅱ , aac (3)-l, aac (3)-Ⅳ, aac (6')- Ⅰ , aac (6')-Ⅰ, apb (3')-Ⅵ, ant (3")-Ⅰ, and ant (2") -Ⅰ were identified by polymerase chain reaction. Results The positive rates of aac (3) - Ⅱ, ant (3") - Ⅰ ,aac (6') - Ⅰ , apb (3') -Ⅵ, and aac (3) - Ⅰ were 85. 7%, 59. 5%, 21.4% , 9. 5%, and 7. 1% , respectively. All the other genotypes were negative. The positive rate of AMEs reached 90. 5% (38 of 42). Conclusions The expression rates of AMEs genes are high among ESBL-KP isolates in our hospital. The aminoglycoside resistance may be relevant with AMEs.
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OBJECTIVE To investigate the incidence rate of Pseudomonas aeruginosa whose ceftazidime resistance was induced by imipenem and the relationship of excretion pump with sensibility of imipenem and ceftazidime.METHODS The sensibility to 15 antibacterials and ceftazidime resistance induced by imipenem were detected by slip diffusion method,detect these bacteriumas′s MIC to Imipenem and Ceftazidime before and after excretion pump inhibitor hydroxide radical cyanogen chlorine phenylhydrazone(CCCP) were added by agar dilution,detect Ceftazidime′s MIC value which were added different concentration imipenem by agar dilution.RESULTS From 325 strains 116 strains(35.7%) were imipenem induced ceftazidime-resistant drug fast,from them 80.2% were imipenem-resistant and ceftazidime-sensitive,19.8% were imipenem and ceftazidime both sensitive.Sensibility to imipenem and ceftazidime was no marked change before and after CCCP added,MIC value of ceftazidime was step up 4-12 times by imipenem.CONCLUSIONS The incidence rate of ceftazidime-resistant P.aeruginosa induced by imipenem is high,clinical microbiological laboratory should evolve D-test to guide clinician use antibacterials more reasonable.
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OBJECTIVE To explore the drug-resistance,the existing forms,genotype,and transfer ways of extended spectrum ?-lactamases(ESBLs) and plasmid AmpC enzyme in Klebsiella pneumoniae.METHODS The drug sensitivity of K.pneumoniae to 17 antibiotics was done by slip-diffusion and microdilution methods.The genotype of two enzymes was assessed by PCR and sequencing.The transfer ways of K.pneumoniae drug-resistant gene were identified by transconjugants-test.RESULTS The ESBLs were mainly produced in 55 cefoxitin resistant K.pneumonia strains.The major genotypes of ESBLs and plasmid AmpC nzyme were CTX-M,MIR and DHA.These genes could be transferred from clinical isolates to recipient bacteria.CONCLUSIONS ESBLs as well as AmpC enzymes are the most important resistance mechanism in K.pneumoniae.The resistance could be transferred through the bacterial conjugation.
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OBJECTIVE To investigate genes associated with aminoglycosides modification enzymes(AMEs)in Pseudomonas aeruginosa(PAE)isolated from NICU patients.METHODS Drug-resistant genes encoding AMEs such as aac(3)-Ⅰ,aac(3)-Ⅱ,aac(3)-Ⅲ、aac(3)-Ⅳ,aac(6')-Ⅰ,aac(6')-Ⅱ,aph(3')-Ⅵ,ant(3″)-Ⅰand ant(2″)-Ⅰwere detected bypoly merase chain reaction(PCR)amplification in 36 PAE isolates.The bacteria were identified by ATB.RESULTS The positive rates of aac(6')-Ⅱ,aac(3)-Ⅱ,aac(6')-Ⅰ and aph(3')-Ⅵ genes were 52.8%,47.2%,11.1% and 2.8% of 36 isolates,respectively.Drug-resistant genes encoding AMEs were detected positively in 77.8% of 36 isolates.CONCLUSIONS AMEs genes are present in high percentage of PAE isolated from NICU patients.
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OBJECTIVE To study the drug resistance genes in imipenem-resistant Pseudomonas aeruginosa.METHODS Five main drug resistance genes:IMP,VIM,SPM and GIM which are pertinent with metal ?-lactamase and outer membrane protein oprD2 gene were analyzed using PCR method.RESULTS The oprD2 genes in 48 strains of imipenem-resistant P.aeruginosa were negative,and in 14 strains were positive from all 62 strains tested.There were 16 strains with positive IMP type and 5 strains with positive VIM type metal enzyme genes positive,7 metal enzymes producing strains were with negative oprD2 gene.The SPM and GIM metal enzyme genes detected were all negative.CONCLUSIONS The loss of outer membrane protein oprD2 gene is the main mechanism of imipenem resistance in P.aeruginosa in Tai′an area.
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OBJECTIVE To analyze the multi-drug resistant genes(genes encoding extended-spectrum ?-lactamases,outer membrane protein gene oprD2,aminoglycoside-modifying enzyme genes,sulfonamides and disinfectant-resistance gene and plasmid-mediated quinolone resistance gene) of Pseudomonas aeruginosa clinical strains.METHODS The drug-resistance to 15 antibiotics was detected by the disc agar diffusion(DAD) and microdilution broth method in 32 P.aeruginosa strains isolated from Jun to Dec 2006.Twenty-eight related drug-resistant genes and outer membrane protein gene oprD2 were examined by PCR method.RESULTS The resistance rate of 32 P.aeruginosa strains to amikacin,ceftazidime,ciprofloxacin,cefepime,cefoperazone/sulbactam,imipenem,meropenem,levofloxacin,piperacillin/tazobactam,aztreonam and piperacillin were 9.4%,25%,59.4%,68.7%,68.8%,78.1%,81.1%,81.3%,84.4% and 94.4%,respectively,and that to others antibiotics were 100%.The detective rate of aminoglycoside-modifying enzyme genes(aac(6′)-Ⅱ,aac(3)-Ⅱ,aac(6′)-Ⅰ,aph(3′)-Ⅵ,ant(3″)-Ⅰ and aac(3)-Ⅰ) were 68.8%,62.5%,21.9%,9.4%,9.4% and 6.3%,and the genes encoding extended-spectrum ?-lactamases(blaFOX,blaIMP,blaVIM and blaDHA) were 37.5% 15.6% 6.3% and 9.3%,respectively.Twenty-two(68.8%) of them were detected in oprD2 and 9(28.1%),but positive in qacE?-sul1 gene.CONCLUSIONS The detective rate of aminoglycoside-modifying enzyme genes,extended-spectrum ?-lactamases genes and the loss rate of outer membrane protein gene oprD2 are high in these 32 multi-drug resistant P.aeruginosa clinical strains.