Metallo-beta-lactamases of Pseudomonas aeruginosa--a novel mechanism resistance to beta-lactam antibiotics.

Abstract

Since about twenty years, following the introduction into therapeutic of news β-lactam antibiotics (broad-spectrum cephalosporins, monobactams and carbapenems), a very significant number of new β-lactamases appeared. These enzymes confer to the bacteria which put them, the means of resisting new molecules. The genetic events involved in this evolution are of two types: evolution of old enzymes by mutation and especially appearance of new genes coming for some, from bacteria of the environment. Numerous mechanisms of enzymatic resistance to the carbapenems have been described in Pseudomonas aeruginosa. The important mechanism of inactivation carbapenems is production variety of b-lactam hydrolysing enzymes associated to carbapenemases. The metallo-β-enzymes (IMP, VIM, SPM, GIM types) are the most clinically significant carbapenemases. P. aeruginosa posses MBLs and seem to have acquired them through transmissible genetic elements (plasmids or transposons associated with integron) and can be transmission to other bacteria. They have reported worldwide but mostly from South East Asia and Europe. The enzymes, belonging to the molecular class B family, are the most worrisome of all β-lactamases because they confer resistance to carbapenems and all the β-lactams (with the exception of aztreonam) and usually to aminoglycosides and quinolones. The dissemination of MBLs genes is thought to be driven by regional consumption of extended -spectrum antibiotics (e.g. cephalosporins and carbapenems), and therefore care must be taken that these drugs are not used unnecessarily.

Highly luminescent silver nanoclusters with tunable emissions: cyclic reduction–decomposition synthesis and antimicrobial properties

“…P. aeruginosa was chosen as a bacterial model to study the antimicrobial properties of the r-Ag NCs. P. aeruginosa has been reported to cause pneumonia, 68 urinary tract infections 68,69 and respiratory system infections in many burn cases 70 and immunesuppressed AIDS patients. 68,71 Recent reports also showed an increased amount of P. aeruginosa resistance towards many conventional antibiotics, such as ampicillin, penicillin and cephalosporin.…”

“…P. aeruginosa has been reported to cause pneumonia, 68 urinary tract infections 68,69 and respiratory system infections in many burn cases 70 and immunesuppressed AIDS patients. 68,71 Recent reports also showed an increased amount of P. aeruginosa resistance towards many conventional antibiotics, such as ampicillin, penicillin and cephalosporin. 24,68 The susceptibility of P. aeruginosa towards r-Ag NCs was first determined by an agar diffusion assay.…”

“…68,71 Recent reports also showed an increased amount of P. aeruginosa resistance towards many conventional antibiotics, such as ampicillin, penicillin and cephalosporin. 24,68 The susceptibility of P. aeruginosa towards r-Ag NCs was first determined by an agar diffusion assay. Our results confirmed that as little as 8 mg of r-Ag NCs can effectively inhibit the growth of P. aeruginosa.…”

The molecular basis of β-lactamase production in Gram-negative bacteria from Saudi Arabia

“…Carbapenem resistance in P. aeruginosa is mostly due to MBLs, including IMP, VIM, SPM, GIM, AIM and DIM enzymes, although other enzymes, including KPC, GES and OXA variants, have been recorded (Sacha et al, 2008;Wang et al, 2010;Juan Nicolau & Oliver, 2010). Multiple mechanisms of resistance often exist in combination (Strateva & Yordanov, 2009;Lister et al, 2009).…”

Occurrence of the <i>aacA4</i> gene among multidrug resistant strains of <i>Pseudomonas aeruginosa</i> isolated from bronchial secretions obtained from the Intensive Therapy Unit at University Hospital in Bialystok, Poland

“…The spread of this organism is often difficult to control, due to the presence of many intrisinic and acquired mechanisms of antimicrobial resistance [3,4].…”