Search results
Results from the WOW.Com Content Network
Overuse of antimicrobial agents and problems with infection control practices have led to the development of multidrug-resistant gram-negative bacterial infections. We used to use carbapenems as the main option in several countries for those severe infections; however, now there are several mechanisms of resistance, including carbapenemase ...
Based upon a number of different observations, including that the gram-positive bacteria are the most sensitive to antibiotics and that the gram-negative bacteria are, in general, resistant to antibiotics, it has been proposed that the outer cell membrane in gram-negative bacteria (diderms) evolved as a protective mechanism against antibiotic ...
Resistance to carbapenem among Enterobacteriaceae and other gram-negative bacteria can be acquired through several mechanisms. Active transport of carbapenem drugs out of the cell, augmented drug efflux, has been observed in some resistant species. [citation needed]
Among gram-negative bacteria, the emergence of resistance to extended-spectrum cephalosporins has been a major concern. It appeared initially in a limited number of bacterial species ( E. cloacae , C. freundii , S. marcescens , and P. aeruginosa ) that could mutate to hyperproduce their chromosomal class C β-lactamase.
The first reports of drug resistant bacterial infections were reported in the 1940s after the first mass production of antibiotics. [3] Most of the RND superfamily transport systems are made of large polypeptide chains. [4] RND proteins exist primarily in gram-negative bacteria but can also be found in gram-positive bacteria, archaea, and ...
Antibiotic resistance mediated by MDR plasmids severely limits the treatment options for the infections caused by Gram-negative bacteria, especially family Enterobacteriaceae. [5] The global spread of MDR plasmids has been enhanced by selective pressure from antimicrobial medications used in medical facilities and when raising animals for food.
The impact of efflux mechanisms on antimicrobial resistance is large; this is usually attributed to the following: The genetic elements encoding efflux pumps may be encoded on chromosomes and/or plasmids , thus contributing to both intrinsic (natural) and acquired resistance respectively.
[4] [1] Tandem gene amplification of antibiotic resistance genes, which results in an increased gene dosage of the resistance genes, is the most common mechanism for unstable heteroresistance in Gram-negative bacteria. [4] [5]