Dataset Information

Emergence of carbapenem resistance due to the novel insertion sequence ISPa8 in Pseudomonas aeruginosa.

ABSTRACT: Chronic lung infections due to the persistence of Pseudomonas aeruginosa in cystic fibrosis patients are typically associated with the emergence of antibiotic resistance. The purpose of this study was to investigate the mechanisms responsible for the emergence of carbapenem resistance when a clinical isolate of P. aeruginosa collected from a patient with cystic fibrosis was challenged with meropenem. Nine carbapenem-resistant mutants were selected with subinhibitory concentrations of meropenem from a clinical isolate of P. aeruginosa and characterized for carbapenem resistance. Increased carbapenem MICs were associated with the identification of the novel insertion sequence ISPa8 within oprD or its promoter region in all the mutants. The position of ISPa8 was different for each of the mutants evaluated. In addition, Southern blot analyses identified multiple copies of ISPa8 within the genomes of the mutants and their parent isolate. These data demonstrate that transposition of IS elements within the Pseudomonas genome can influence antibiotic susceptibility. Understanding the selective pressures associated with the emergence of antibiotic resistance is critical for the judicious use of antimicrobial chemotherapy and the successful treatment of bacterial infections.

SUBMITTER: Fowler RC

PROVIDER: S-EPMC3948848 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Emergence of carbapenem resistance due to the novel insertion sequence ISPa8 in Pseudomonas aeruginosa.

Fowler Randal C RC Hanson Nancy D ND

PloS one 20140310 3

Chronic lung infections due to the persistence of Pseudomonas aeruginosa in cystic fibrosis patients are typically associated with the emergence of antibiotic resistance. The purpose of this study was to investigate the mechanisms responsible for the emergence of carbapenem resistance when a clinical isolate of P. aeruginosa collected from a patient with cystic fibrosis was challenged with meropenem. Nine carbapenem-resistant mutants were selected with subinhibitory concentrations of meropenem f ...[more]

PMID: 24614163

Similar Datasets

Project description:This study established the in vitro activity of ceftolozane/tazobactam (C/T) and its genotypic resistance mechanisms by whole-genome sequencing (WGS) in 195 carbapenem-nonsusceptible Pseudomonas aeruginosa (CNSPA) clinical isolates recovered from Singapore between 2009 and 2020. C/T susceptibility rates were low, at 37.9%. Cross-resistance to ceftazidime/avibactam was observed, although susceptibility to the agent was slightly higher, at 41.0%. Whole-genome sequencing revealed that C/T resistance was largely mediated by the presence of horizontally acquired ?-lactamases, especially metallo-?-lactamases. These were primarily disseminated in well-recognized high-risk clones belonging to sequence types (ST) 235, 308, and 179. C/T resistance was also observed in several non-carbapenemase-producing isolates, in which resistance was likely mediated by ?-lactamases and, to a smaller extent, mutations in AmpC-related genes. There was no obvious mechanism of resistance observed in five isolates. The high C/T resistance highlights the limited utility of the agent as an empirical agent in our setting. Knowledge of local molecular epidemiology is crucial in determining the potential of therapy with novel agents.IMPORTANCE Pseudomonas aeruginosa infection is one of the most difficult health care-associated infections to treat due to the ability of the organism to acquire a multitude of resistance mechanisms and express the multidrug resistance phenotype. Ceftolozane/tazobactam (C/T), a novel ?-lactam/?-lactamase inhibitor combination, addresses an unmet medical need in patients with these multidrug-resistant P. aeruginosa infections. Our findings demonstrate geographical variation in C/T susceptibility owing to the distinct local molecular epidemiology. This study adds on to the growing knowledge of C/T resistance, particularly mutational resistance, and will aid in the design of future ?-lactams and ?-lactamase inhibitors. WGS proved to be a useful tool to understand the P. aeruginosa resistome and its contribution to emerging resistance in novel antimicrobial agents.

Project description:Carbapenem-resistant Pseudomonas aeruginosa (CRPA) has become a serious challenge in the clinic. Recently, the prevalence of CRPA isolates carrying the blaKPC-2 gene has been increasing in China. Ceftazidime-avibactam (CZA) has shown good efficacy against large portions of KPC-2-producing CRPA strains. However, with the increasing usage of this drug, CZA resistance in CRPA strains has been reported. Here, we reported for the first time that resistance of the ST463 CRPA strain to CZA was caused by a novel variant in the KPC gene that arose after CZA exposure. The CRPA strain PA2207 is a carbapenem- and CZA-resistant strain that harbors a mutated blaKPC gene, named blaKPC-90. Cloning and expression of blaKPC-90 in Escherichia coli DH5α revealed that KPC-90 led to a 64-fold increase in the MIC value of CZA. Conjugation experiments further confirmed that blaKPC-90 was located on a conjugative plasmid. Whole-genome sequencing analysis showed that this plasmid had high sequence similarity to a previously reported novel blaKPC-2-harboring plasmid in a clinical P. aeruginosa strain isolated in China. In addition, overexpression of an efflux pump (MexXY-OprM) might be associated with the CZA resistance phenotype, as determined by reverse transcription-quantitative PCR and efflux pump inhibition experiments. For the first time, we reported a KPC variant, KPC-90, in a clinical ST463 CRPA strain with CZA resistance that was mediated by a 2 amino acid insertion outside the KPC omega-loop region. Our study further highlights that diverse KPC variants that mediate CZA resistance have emerged in the CRPA strain. Furthermore, KPC-90 mutation combined with efflux pump overexpression resulted in a high level of resistance to CZA in the PA2207 isolate. Effective surveillance should be conducted to prevent CZA resistance from spreading in the CRPA strain. IMPORTANCE For the first time, we reported a KPC variant, KPC-90, in a clinical ST463 CRPA strain with CZA resistance. CZA resistance was mediated by a 2 amino acid insertion outside the KPC omega-loop region in CRPA. Our study further emphasized that CZA resistance caused by blaKPC gene mutation could be selected in CRPA after CZA therapy. Considering the widespread presence of the ST463 CRPA strain in China, clinicians should pay attention to the risk of the development of CZA resistance in CRPA strains under treatment pressure.

Project description:The emergence of carbapenem-resistant Pseudomonas aeruginosa represents a worldwide problem. To understand the carbapenem-resistance mechanisms and their spreading among P. aeruginosa strains, whole genome sequences were determined of two extensively drug-resistant strains that are endemic in Dutch hospitals. Strain Carb01 63 is of O-antigen serotype O12 and of sequence type ST111, whilst S04 90 is a serotype O11 strain of ST446. Both strains carry a gene for metallo-β-lactamase VIM-2 flanked by two aacA29 genes encoding aminoglycoside acetyltransferases on a class 1 integron. The integron is located on the chromosome in strain Carb01 63 and on a plasmid in strain S04 90. The backbone of the 159-kb plasmid, designated pS04 90, is similar to a previously described plasmid, pND6-2, from Pseudomonas putida. Analysis of the context of the integron showed that it is present in both strains on a ∼30-kb mosaic DNA segment composed of four different transposons that can presumably act together as a novel, active, composite transposon. Apart from the presence of a 1237-bp insertion sequence element in the composite transposon on pS04 90, these transposons show > 99% sequence identity indicating that transposition between plasmid and chromosome could have occurred only very recently. The pS04 90 plasmid could be transferred by conjugation to a susceptible P. aeruginosa strain. A second class 1 integron containing a gene for a CARB-2 β-lactamase flanked by an aacA4'-8 and an aadA2 gene, encoding an aminoglycoside acetyltransferase and adenylyltransferase, respectively, was present only in strain Carb01 63. This integron is located also on a composite transposon that is inserted in an integrative and conjugative element on the chromosome. Additionally, this strain contains a frameshift mutation in the oprD gene encoding a porin involved in the transport of carbapenems across the outer membrane. Together, the results demonstrate that integron-encoded carbapenem and carbapenicillin resistance can easily be disseminated by transposition and conjugation among Pseudomonas aeruginosa strains.

Dataset Information

Emergence of carbapenem resistance due to the novel insertion sequence ISPa8 in Pseudomonas aeruginosa.

Publications

Emergence of carbapenem resistance due to the novel insertion sequence ISPa8 in Pseudomonas aeruginosa.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets