泛耐药铜绿突变和获得性耐药机制

朱德权

朱德权

P22079532[1]突变和水平获得耐药.pdf (381.56 KB, 下载次数: 66)

2012-2-11 19:58 上传

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Interplay between mutational and horizontally acquired resistance mechanisms and its association with carbapenem resistance amongst extensively drug-resistant Pseudomonas aeruginosa (XDR-PA)

a b s t r a c t
Between 2003 and 2009, the prevalence of extensively drug-resistant Pseudomonas aeruginosa (XDRPA)
increased significantly in northern Taiwan from 1.0% to 2.1%. Molecular methods were used to
investigate the genetic relatedness and carbapenem resistance mechanisms of a collection of 203 nonrepetitive
XDR-PA isolates available for study. Using pulsed-field gel electrophoresis (PFGE), 52 genotypes
were observed; one predominant genotype (pulsotype 1) was found in 57.6% of the isolates. Polymerase
chain reaction (PCR), sequencing and quantitative reverse-transcriptase PCR analyses demonstrated that
one horizontally acquired mechanism [metallo--lactamase (MBL) genes] and two mutational mechanisms
(efflux and porins) accounted for the carbapenem resistance. The most predominant horizontally
acquired mechanism was carriage of blaVIM-3, which was found in 61.1% of isolates. Decreased expression
of oprD was the most prevalent mutational mechanism and was found in 70.0% of the XDR-PA
isolates, whereas overexpression of mexA was found in 27.6% of the isolates. The highlight of this study
was the discovery of statistically significant relationships between certain horizontally acquired and
mutational resistance mechanisms and their contribution to carbapenem susceptibility. MBL-producers
expressed significantly lower MexAB and higher OprD than non-MBL-producers. Amongst isolates without
an acquired -lactamase gene, oprD expression was significantly reduced, whilst expression of efflux
pumps was increased. Reduced OprD expression alone or the production of VIM-type MBLs showed similar
contributions to a low to intermediate MIC50 (minimum inhibitory concentration for 50% of the
organisms) for carbapenems. Isolates with reduced OprD expression that simultaneously harboured
blaVIM exhibited high levels of resistance to carbapenems, which implied that these two mechanisms
had a synergistic effect on the MICs.

朱德权

P19996144[1]全球播散耐碳青霉烯不动杆菌.pdf (236.85 KB, 下载次数: 47)

2012-2-11 19:59 上传

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Global spread of carbapenem-resistant Acinetobacter baumannii

Objectives: We have investigated the molecular epidemiology and distribution of carbapenemase genes in 492
imipenem-non-susceptible Acinetobacter baumannii worldwide isolates (North and Latin America, Europe, Asia,
South Africa and Australia).
Methods: MICs were determined by broth microdilution and Etest. The presence of carbapenemase-encoding
genes was investigated by PCR. Molecular epidemiology was performed by repetitive sequence-based PCR (rep-
PCR; DiversiLab), sequence-type multiplex PCR and PFGE.
Results: Imipenem non-susceptibility was associated with ISAba1 upstream of the intrinsic blaOXA-51-like or the
acquired carbapenemase blaOXA-23-like, blaOXA-40-like or blaOXA-58-like. Isolates were grouped into eight distinct
clusters including European clones I, II and III. European clone II was the largest (246 isolates) and most widespread
group (USA, pan-Europe, Israel, Asia, Australia and South Africa).
Conclusions: The global dissemination of eight carbapenem-resistant lineages illustrates the success this
organism has had in epidemic spread. The acquired OXA enzymes are widely distributed but are not the sole
carbapenem resistance determinant in A. baumannii.

朱德权

P21375657[1]肺囊性纤维化耐碳青霉烯铜绿.pdf (71.62 KB, 下载次数: 23)

2012-2-11 20:00 上传

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Pseudomonas aeruginosa infection in cystic fibrosis caused by an epidemic metallob-lactamase-producing clone with a heterogeneous carbapenem resistance phenotype

Abstract
An epidemic IMP-13 metallo-b-lactamase (MBL)-producing Pseudomonas aeruginosa clone, causing infections and even large
outbreaks in Italian critical care settings, was detected in a young cystic fibrosis patient. In this patient, the chronic infection
was sustained by distinct clonal sub-populations of the MBL-producing P. aeruginosa clone, either susceptible or resistant
to carbapenems. These findings underscore the importance of infection prevention practices in cystic fibrosis settings and pose an important diagnostic and therapeutic challenge.

木木

已下载。会认真学习。感谢！

星怡

谢谢分享，下载了慢慢学习！

沧海一声笑

Acinetobacter baumannii is a serious challenge to patients.

细雨润竹

几份不错的资料，尤其铜绿假单胞菌的耐药问题一直是近年来困扰本院临床的老大难问题，好好学习，天天向上

yunyun1973

下载了，认真的学习。感谢老师！

玉玲珑

谢谢分享很好的文献，2篇是2011年发表的关于泛耐药铜绿假单胞菌，1篇是2010年发表的鲍曼不动杆菌的。

天天，天蓝

高山大海

都是英文呀，没学过英文，看不懂。