1. Mutational and acquired carbapenem resistance mechanisms in multidrug resistant Pseudomonas aeruginosa clinical isolates from Recife, Brazil.
- Author
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Cavalcanti FL, Mirones CR, Paucar ER, Montes LÁ, Leal-Balbino TC, Morais MM, Martínez-Martínez L, and Ocampo-Sosa AA
- Subjects
- Aminoglycosides metabolism, Amphotericin B analogs & derivatives, Amphotericin B metabolism, Antifungal Agents metabolism, Brazil, Cephalosporinase classification, Cephalosporinase metabolism, Codon, Nonsense metabolism, Enzyme Activation genetics, Frameshift Mutation genetics, Gene Expression Regulation, Bacterial genetics, Humans, Membrane Transport Proteins metabolism, Methyltransferases metabolism, Nucleotidyltransferases metabolism, Point Mutation genetics, Porins metabolism, Pseudomonas aeruginosa enzymology, Pseudomonas aeruginosa isolation & purification, Repetitive Sequences, Nucleic Acid, beta-Lactamases genetics, Carbapenems metabolism, Drug Resistance, Multiple, Bacterial genetics, Mutation, Pseudomonas aeruginosa drug effects, Pseudomonas aeruginosa genetics, beta-Lactam Resistance genetics, beta-Lactamases metabolism
- Abstract
An investigation was carried out into the genetic mechanisms responsible for multidrug resistance in nine carbapenem-resistant Pseudomonas aeruginosa isolates from different hospitals in Recife, Brazil. Susceptibility to antimicrobial agents was determined by broth microdilution. Polymerase chain reaction (PCR) was employed to detect the presence of genes encoding β-lactamases, aminoglycoside-modifying enzymes (AMEs), 16S rRNA methylases, integron-related genes and OprD. Expression of genes coding for efflux pumps and AmpC cephalosporinase were assessed by quantitative PCR. The outer membrane proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The blaSPM-1, blaKPC-2 and blaGES-1 genes were detected in P. aeruginosa isolates in addition to different AME genes. The loss of OprD in nine isolates was mainly due to frameshift mutations, premature stop codons and point mutations. An association of loss of OprD with the overexpression of MexAB-OprM and MexXY-OprM was observed in most isolates. Hyper-production of AmpC was also observed in three isolates. Clonal relationship of the isolates was determined by repetitive element palindromic-PCR and multilocus sequence typing. Our results show that the loss of OprD along with overexpression of efflux pumps and β-lactamase production were responsible for the multidrug resistance in the isolates analysed.
- Published
- 2015
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