Doripenem is a broad-spectrum parenteral carbapenem under clinical development in Japan and North America. Its activities against (i) Pseudomonas aeruginosa isolates with graded levels of intrinsic efflux-type resistance, (ii) mutants with various combinations of AmpC and OprD expression, (iii) PU21 transconjugants with class A and D beta-lactamases, and (iv) P. aeruginosa isolates with metallo...

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-m...

In order to define the contributions of the mechanisms for carbapenem resistance in clinical strains of Pseudomonas aeruginosa, we investigated the presence of OprD, the expressions of the MexAB-OprM and MexEF-OprN systems, and the production of the beta-lactamases for 44 clinical strains. All of the carbapenem-resistant isolates showed the loss of or decreased levels of OprD. Three strains ove...

Background: The opportunistic human pathogen, Pseudomonas aeruginosa, is a critical cause of nosocomial infection with high morbidity and mortality rate. Eradication P. aeruginosa has been troublesome due to its capacity develop strong multidrug resistance (MDR). Objectives: purposes this study were define the pattern antimicrobial sensitivity, typing, prevalence metallo-β-lactamase (MBL) detec...

The activity of imipenem against Pseudomonas aeruginosa HUS-3 decreased by 16 times in the presence of substances eluted from siliconized latex urinary catheters (SLUCs). SLUCs did not inactivate imipenem or increase beta-lactamase activity. The outer membrane of P. aeruginosa HUS-3 grown in the presence of eluate lacked an OprD-like protein and expressed a new 50-kDa protein. The decreased act...

The F plasmid-carried bacterial toxin, the CcdB protein, is known to act on DNA gyrase in two different ways. CcdB poisons the gyrase-DNA complex, blocking the passage of polymerases and leading to double-strand breakage of the DNA. Alternatively, in cells that overexpress CcdB, the A subunit of DNA gyrase (GyrA) has been found as an inactive complex with CcdB. We have reconstituted the inactiv...

Background: Emergence Klebsiella pneumoniae resistant to quinolone antibiotics due to mutations in gyrA and parC genes created problem for treatment of patients in different hospitals in Iran. The objective of this study was to determine the amino acid substitutions of GyrA and ParC proteins in certain clonal lineages of the K. pneumoniae conferring high level quinolone resistance. Methods: One...