Mutational inactivation of OprD in carbapenem-resistant Pseudomonas aeruginosa isolates from Korean hospitals

Abstract

In our previous study, the first structural gene (GGTI) encoding g-glutamyl transpeptidase was cloned and characterized from the fission yeast Schizosaccharomyces pombe, and its transcription, using the GGTI-lacZ fusion gene, containing the 1,085 bp upstream region from the translational initiation point, was found to be enhanced by sodium nitroprusside and L-buthionine-(S,R)-sulfoximine (BSO). In the present work, regulation of the GGTI gene was further elucidated. Non-fermentable carbon sources, such as acetate and ethanol, markedly enhanced the synthesis of beta-galactosidase from the GGTI-lacZ fusion gene. However, its induction by non-fermentable carbon sources appeared to be independent of the presence of the Pap1 protein. Nitrogen starvation also gave rise to induction of GGTI gene expression in a Pap1-independent manner. The three additional fusion plasmids, carrying 754, 421 and 156 bp regions, were constructed. The sequence responsible for the induction by non-fermentable carbon sources and nitrogen starvation was identified to exist within a -421 bp region of the GGTI gene. Taken together, the S. pombe GGTI gene is regulated by non-fermentable carbon sources and nitrogen starvation.

Molecular characterization of resistance mechanisms in Pseudomonas aeruginosa isolates resistant to carbapenems

“…In the study of Yi et al, 2006 [40], imipenem resistance is mainly mediated by OprD deficiency. In agreement with that, Kim and coauthors have recently reported that OprD inactivation is the most common mechanism of carbapenem resistance in P. aeruginosa isolated from Korean patients [42].…”

Exploring the success of Brazilian endemic clone Pseudomonas aeruginosa ST277 and its association with the CRISPR-Cas system type I-C

“…On the other hand, the literature does not associate the PmrA and NalC amino acid changes observed here to resistant strains [25,26]. In addition, the 20 oprD mutations identified for all strains may be a feature of ST277, as specific amino acid substitutions in OprD have been potentially associated to MLST profiles [24].…”

“…We analyzed mutational events in some genes that can contribute to enhance the bacterial resistance phenotype. Among these genetic alterations, those already described as related to increased resistance are: activator deletion of mexT that leads to low sensitivity to chlorophenylcholine and fluoroquinolones [20]; mexZ nucleotide deletion associated to aminoglycoside, cefepime, tetracyclines and macrolides resistance [8,21]; mutation in PhoQ linked to colistin-resistant phenotype [22]; GyrA alterations creating quinolone-resistant strains [23]; and oprD frameshift related to imipenem resistance [8,24]. On the other hand, the literature does not associate the PmrA and NalC amino acid changes observed here to resistant strains [25,26].…”

Exploring the success of Brazilian endemic clone Pseudomonas aeruginosa ST277 and its association with the CRISPR-Cas system type I-C

“…Only two mutations are nonsynonymous, but they are unable to affect the flow of molecules through this bacterial membrane' pore. The presence of a potential association has been suggested between specific amino acid substitutions in OprD and MLST profiles [26] . Perhaps the mutations observed here can be characteristic of ST277.…”