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Objective To investigate the molecular mechanism of resistance to carbapenems in Pseudomonas aeruginasa from 5 teaching hospitals in Beijing. Methods A total of 213 non-duplicate imipenem-resistant Pseudomonas aernginosa (IRPA) isolates were collected from 5 hospitals in Beijing from June 2004 to December 2005. The minimal inhibitory concentrations (MICs) of meropenem, imipenem and others antibiotics were determined by agar dilution method. Disk diffusion test was used for screening metalloenzymes. The bla IMP,bla VIM and OprD2 genes were amplified by PCR and only sequenced. Results Out of 213 isolates, OprD2 loss was detected in 84 isolates and IMP-1 enzyme was detected in 6 isolates simultaneously. Thirteen IRPAs only produced IMP-1 and 2 isolates only produced VIM-2. Conclusion OprD2 loss and metallo-β-lactamuse production are the parts of the mechanisms of resistance to carbapenems in Pseudomonas aeruginosa in Beijing.
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OBJECTIVE To study 40 kinds of resistant-related genes in a pan-resistant Pseudomonas aeruginosa.METHODS To detect the susceptibility of antimicrobial agents by MIC,40 resistant-related genes including 29 ?-lactamases genes,porin oprD2 genes,6 aminoglycoside-modifying enzymes(AMEs)genes,chlorhexidine/sulfadiazine resistant gene(qacE△1-sul1)and intergron(intⅠ1,2,3),etc,form 1 strain of P.aeruginosa were measured by PCR,and verified by DNA sequencing.RESULTS In the strain,there were positive of 6 kinds of resistant-related genes(blaTEM,blaOXA10,aac(6′)-Ⅱ,aac(3)-Ⅱ,qacE△1-sul1 and intⅠ1),but without oprD2 genes.Twenty-seven kinds of ?-lactamases genes,4 kinds of AMEs(aac(6′)-Ⅰb,aac(3)-Ⅰ,ant(3″)-Ⅰ and ant(2″)-Ⅰ),and 2 kinds of intⅠ(intⅠ2 and intⅠ3) were negative.CONCLUSIONS The multi-resistant mechanisms of pan-resistant P.aeruginosa are mainly related to 7 kinds of resistant-related genes(blaTEM,blaOXA10,oprD2,aac(6′)-Ⅱ,aac(3)-Ⅱ,qacE△1-sul1 and intⅠ1).
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Objective To investigate the loss of outer membrane protein D2 (OprD2) gene in imipenem-resistant Pseudomonas aeruginosa.Methods The minimal inhibitory concentrations (MIC) of 10 antimicrobial agents against 80 strains of imipenem-resistant clinical isolates were determined by agar dilution method.PCR was used to detect OprD2 gene.Results PCR results showed that 44 of the 80 isolates of imipenem-resistant P.aeruginosa were positive for OprD2 gene.There was significant difference (P
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0.05).Thirty genotypes were got from 54 strains by ERIC-PCR.CONCLUSIONS There isn′t significant difference on the absence rate of oprD2 gene in Tianjin and it gives us a hint that other factors can also result in the prevalence of IRPA.The existence of prevalence of IRPA clone in some departments advises us to effectively control the IRPA in hospital.
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OBJECTIVE:To investigate the mechanism of imipenem-resistance in clinical isolates of Pseudomonas aeruginos (PA). METHODS: 55 strains of PA had been isolated from sputum specimen in clinic and their drug sensitivity to imipenem was tested by K-B slip diffusion method. Their amount of outer membrane protein OprD2 was analyzed by SDS-PAGE with outer membrane protein profiles. Metallo-?-lactamases (MBLs) was detected by double-disk synergy test (DDST). RESULTS: 36 strains of imipenem-resistant and 19 strains of imipenem-sensitive PA isolated were studied. The amount of OprD2 showed a various degree of reduction in all resistant isolates, and the relative amount of OprD2 in resistant isolates were significantly lower than in sensitive isolates (P