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...

Objective(s): We investigated the contribution of gyrA and parC mutational mechanism in decreased ciprofloxacin susceptibility of Acinetobacter baumannii isolated from burn wound infections. Materials and Methods: Ciprofloxacin susceptibility of 50 A. baumannii isolates was evaluated by disk diffusion and agar dilution methods. PCR and sequencing were performed for detection of mutation in gyr...

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...

Objectives To provide information about the genetic relationships and mechanism underlying carbapenem resistance in Pseudomonas aeruginosa clinical isolates of a hospital in China. Materials and methods One hundred and sixty P. aeruginosa strains were isolated from a hospital in China. Susceptibility to 14 antimicrobial agents was determined by antimicrobial susceptibility testing. Multilocus...

Background.  Successful treatment of infections caused by multidrug-resistant (MDR) Pseudomonas aeruginosa is thwarted by the emergence of antibiotic resistance and biofilm formation on prosthetic devices. Our aims were to decipher the molecular basis of resistance in a unique case of prosthetic valve endocarditis (PVE) caused by MDR P. aeruginosa. Methods.  Five sequential MDR P. aeruginosa bl...

The OprD family of specific porins in Pseudomonas aeruginosa comprises 19 members, some of which have been demonstrated to facilitate the uptake of specific compounds into the cell. The members of this family share considerable amino acid sequence similarity (46–57%), which is unusual among porin molecules. In this work, we sought to establish whether this sequence conservation was the basis fo...

Quinolones are a large and widely consumed class of synthetic drugs. Expanded-spectrum quinolones, like ciprofloxacin are highly effective against Gram-negative bacteria, especially Escherichia coli. In E. coli the major target for quinolones is DNA gyrase. This enzyme is composed of two subunits, GyrA and GyrB encoding by gyrA and gyrB, respectively. Mutations in either of these genes cause qu...

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...