AmpC and OprD Are Not Involved in the Mechanism of Imipenem Hypersusceptibility among
 Pseudomonas aeruginosa
 Isolates Overexpressing the
 mexCD
 -
 oprJ
 Efflux Pump

Wolter, Daniel J.; Hanson, Nancy D.; Lister, Philip

doi:10.1128/aac.49.11.4763-4766.2005

Cited by 25 publications

(28 citation statements)

References 25 publications

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“…Although other investigators have suggested that imipenem hypersusceptibility is a result of disrupted ampC induction (151), the observation VOL. 22,2009 ANTIBACTERIAL-RESISTANT PSEUDOMONAS AERUGINOSA 601 that AmpC overproduction does not significantly increase imipenem MICs (63,131,169,274) argues against this hypothesis. Furthermore, our own studies have shown that imipenem-hypersusceptible mutants can be selected from P. aeruginosa parent strains that are partially and fully derepressed for ampC expression, without any changes in either the expression of ampC or AmpC hydrolysis activity (274).…”

Section: Mexcd-oprj Overproduction and Hypersusceptibility To Antibacmentioning

confidence: 69%

“…Although data from our own studies also showed decreased induction of ampC expression associated with overexpression of mexCD-oprJ (274), this association was observed only in isogenic mutants from a clinical isolate with wild-type ampC expression. When the parent strains were derepressed for ampC expression, overexpression of mexC was not associated with any change in ampC expression among the isogenic mutants selected (274).…”

Section: Mexcd-oprj Overproduction and Hypersusceptibility To Antibacmentioning

confidence: 85%

“…In contrast, published data have suggested that overproduction of AmpC does not play a discernible role in the development of carbapenem resistance among P. aeruginosa isolates. AmpC overproduction among isogenic mutants selected with ␤-lactams does not significantly decrease P. aeruginosa susceptibility to carbapenems (63,131,169,274). In addition, AmpC overproduction in carbapenemsusceptible clinical isolates of P. aeruginosa has been reported.…”

Section: Ampc-mediated Resistancementioning

confidence: 94%

“…The second example is an isogenic imipenem-hypersusceptible mutant, P. aeruginosa 244-921C, that was selected from an imipenem-resistant clinical isolate, P. aeruginosa strain 244, using ciprofloxacin (274). The mechanism of imipenem resistance for P. aeruginosa 244 (MIC ϭ 16 g/ml) was shown to be a base transition creating a premature stop codon and preventing translation of full-length OprD.…”

Section: Discordance Between Oprd Expression and Susceptibility To Immentioning

confidence: 99%

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Antibacterial-ResistantPseudomonas aeruginosa: Clinical Impact and Complex Regulation of Chromosomally Encoded Resistance Mechanisms

2009

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SUMMARY Treatment of infectious diseases becomes more challenging with each passing year. This is especially true for infections caused by the opportunistic pathogen Pseudomonas aeruginosa, with its ability to rapidly develop resistance to multiple classes of antibiotics. Although the import of resistance mechanisms on mobile genetic elements is always a concern, the most difficult challenge we face with P. aeruginosa is its ability to rapidly develop resistance during the course of treating an infection. The chromosomally encoded AmpC cephalosporinase, the outer membrane porin OprD, and the multidrug efflux pumps are particularly relevant to this therapeutic challenge. The discussion presented in this review highlights the clinical significance of these chromosomally encoded resistance mechanisms, as well as the complex mechanisms/pathways by which P. aeruginosa regulates their expression. Although a great deal of knowledge has been gained toward understanding the regulation of AmpC, OprD, and efflux pumps in P. aeruginosa, it is clear that we have much to learn about how this resourceful pathogen coregulates different resistance mechanisms to overcome the antibacterial challenges it faces.

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Section: Mexcd-oprj Overproduction and Hypersusceptibility To Antibacmentioning

confidence: 69%

Section: Mexcd-oprj Overproduction and Hypersusceptibility To Antibacmentioning

confidence: 85%

Section: Ampc-mediated Resistancementioning

confidence: 94%

Section: Discordance Between Oprd Expression and Susceptibility To Immentioning

confidence: 99%

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Antibacterial-ResistantPseudomonas aeruginosa: Clinical Impact and Complex Regulation of Chromosomally Encoded Resistance Mechanisms

2009

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“…MBLs are reported to be resistant to all β-lactam antibiotics except for Monobactams such as Aztreonam (9,19). In this study, 96.87% of the isolates were resistant to aztreonam, suggesting coexistence of other resistance mechanisms such as AmpC type β-lactamases or MexAB-OprM Efflux Pumps (25)(26)(27).…”

Section: Discussionmentioning

confidence: 99%

Coexistence of AmpC and Extended-Spectrum β-lactamases in Metallo-β-Lactamase Producing Pseudomonas aeruginosa Burn Isolates in Tehran

Salimi

Eftekhar

2013

Jundishapur J Microbiol

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Background: Multi-drug resistant Pseudomonas aeruginosa causes serious complications in burn patients. One of the most important mechanisms of resistance to β-lactam antibiotics is hydrolysis of antibiotics by various β-lactamases. In recent years, Carbapenems have been widely used for treatment of P. aeruginosa infections. However, the organisms have become resistant to Carbapenems mostly by producing metallo β-lactamases. Objectives: The aim of this study was to determine antibiotic susceptibility, production of extended spectrum and AmpC β-lactamases in metallo β-lactamase producing P. aeruginosa burn isolates. Materials and Methods: Antibiotic susceptibility of 135 P. aeruginosa burn isolates was determined by disc diffusion. Metallo β-lactamase production was screened by the double disc synergy test. Metallo β-lactamase producing bacteria were then tested for extended spectrum β-lactamase production by the combined disc diffusion method. AmpC production was carried out using AmpC disc test. Results: There was 99% resistance to Carbenicillin, and Ticarcillin, 98% to Cotrimoxazole, 96% to Ciprofloxacin, and Aztreonam, 95% to Imipenem, and Meropenem, 94% to Pperacillin, 93% to Tobramycin, 92% to Cefepime, 90% to Amikacin, 89% to Ceftazidime, and 87% to Piperacillin-tazobactam. Among the 128 Imipenem resistant isolates, 32 (25%) were capable of producing metallo β-lactamases of which, 4 (12.5%) produced extended spectrum and 26 (81%) produced AmpC β-lactamases. Four isolates (12.5%) produced all 3 types. Conclusions: This study showed that multiple β-lactamases can be produced in burn isolates. This suggests that use of Cephalosporins and Carbapenems should be restricted in burn isolates to minimize the development and spread of these multidrug resistant pathogens.

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Antimicrobial Drug Efflux Pumps in Pseudomonas aeruginosa

Plésiat

2016

Efflux-Mediated Antimicrobial Resistance in Bacteria

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AmpC and OprD Are Not Involved in the Mechanism of Imipenem Hypersusceptibility among Pseudomonas aeruginosa Isolates Overexpressing the mexCD - oprJ Efflux Pump

Cited by 25 publications

References 25 publications

Antibacterial-ResistantPseudomonas aeruginosa: Clinical Impact and Complex Regulation of Chromosomally Encoded Resistance Mechanisms

Antibacterial-ResistantPseudomonas aeruginosa: Clinical Impact and Complex Regulation of Chromosomally Encoded Resistance Mechanisms

Coexistence of AmpC and Extended-Spectrum β-lactamases in Metallo-β-Lactamase Producing Pseudomonas aeruginosa Burn Isolates in Tehran

Antimicrobial Drug Efflux Pumps in Pseudomonas aeruginosa

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