To circumvent the permeability barrier of its outer membrane, Pseudomonas aeruginosa has evolved a series of specific porins. These channels have binding sites for related classes of molecules that facilitate uptake under nutrient-limited conditions. Here, we report on the identification of a 19-member family of porins similar to the basic-amino-acid-specific porin OprD. The members of this fam...

BACKGROUND AND OBJECTIVES The oprD mutation and AmpC overproduction are the main mechanisms of intrinsic resistance to carbapenems such as imipenem and meropenem in Pseudomonas aeruginosa. MATERIALS AND METHODS In this study, we investigated intrinsic resistance to carbapenems including mutation of oprD and AmpC overproduction in a carbapenem-resistant P. aeruginosa isolated from a burn patie...

Carbapenem-resistance is a great challenge for antimicrobial therapy in Pseudomonas aeruginosa multidrug-resistant infections, as it reduces therapeutic options. This study investigated carbapenem-resistance mechanisms six strains of non-carbapenemase-producing P. aeruginosa. Minimal inhibitory concentrations imipenem and meropenem were determined by epsilometric test broth microdilution. Mutat...

BACKGROUND Pseudomonas aeruginosa can become resistant to carbapenems by both intrinsic (mutation-driven) and transferable (β-lactamase-based) mechanisms. Knowledge of the prevalence of these various mechanisms is important in intensive care units (ICUs) in order to define optimal prevention and therapeutic strategies. METHODS A total of 109 imipenem-non-susceptible (MIC >4 mg/L) strains of P...

The activities of carbapenems against Pseudomonas aeruginosa decreased in the presence of siliconized latex urinary catheters (SLUCs). This effect was associated with the loss of OprD. The zinc that eluted from SLUCs is responsible for this phenomenon. We have found that zinc exerts a negative effect on the expression of OprD, the porin responsible for carbapenem entry into P. aeruginosa.

Pseudomonas aeruginosa OprD is a specific porin which facilitates the uptake of basic amino acids and imipenem across the outer membrane. In this study, we examined the effects of deletions in six of the proposed eight surface loops of OprD on the in vivo and in vitro functions of this protein. Native OprD formed very small channels in planar lipid bilayers, with an average single-channel condu...

conclusions the results of this study indicated that a decrease in oprd gene expression is an important mechanism of resistance in carbapenem resistant pseudomonas aeruginosa isolated from severe burn patients with secondary infection. results our study showed that 94.2% of the isolates were resistant to imipenem, 99.5% to meropenem, and all were resistant to ertapenem. the oprd gene expression...