Mechanisms of Antibiotic Resistance in Important Gram-Positive and Gram-Negative Pathogens and Novel Antibiotic Solutions

Abstract

Multidrug-resistant bacteria have on overwhelming impact on human health, as they cause over 670,000 infections and 33,000 deaths annually in the European Union alone. Of these, the vast majority of infections and deaths are caused by only a handful of species—multi-drug resistant Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus spp., Acinetobacter spp. and Klebsiella pneumoniae. These pathogens employ a multitude of antibiotic resistance mechanisms, such as the production of antibiotic deactivating enzymes, changes in antibiotic targets, or a reduction of intracellular antibiotic concentration, which render them insusceptible to multiple antibiotics. The purpose of this review is to summarize in a clinical manner the resistance mechanisms of each of these 6 pathogens, as well as the mechanisms of recently developed antibiotics designed to overcome them. Through a basic understanding of the mechanisms of antibiotic resistance, the clinician can better comprehend and predict resistance patterns even to antibiotics not reported on the antibiogram and can subsequently select the most appropriate antibiotic for the pathogen in question.

Antibiotic Susceptibility Profile of Pseudomonas aeruginosa Canine Isolates from a Multicentric Study in Romania

“…Intrinsic include influx pumps, as well as several β-lactamases. Specifically, P. aeruginosa has chromosomally encoded AmpC β-lactamases and extended-spectrum-β-lactamases (ESBLs) [22].…”

“…Acquired β-lactam resistance mechanisms in P. aeruginosa include mutations in porins, such as deficiency of the OprD porin, which leads to high-level resistance to imipenem and other carbapenems; overexpression of hydrolyzing enzymes such as AmpC; over-expression of efflux pumps such as MexCD-OprJ, which reduces susceptibility to carbapenems; modification of PBPs, which reduces susceptibility to several β-lactams; and finally, acquisition of other β-lactamases, such as Class B carbapenemases [22][23][24].…”

Antioxidants: Classification, Natural Sources, Activity/Capacity Measurements, and Usefulness for the Synthesis of Nanoparticles

“…The most dangerous are biofilms composed of pathogenic bacteria E. faecalis , S. aureus , Staphylococcus epidermidis, E. coli , Klebsiella pneumoniae , and P. aeruginosa [ 358 ], which are mostly responsible for hospital infections that are difficult to cure and are characterized by increased resistance to therapies [ 359 ]. The antibiotic resistance of biophimes is the result of, among other things, the presence of a matrix that is a barrier to drug penetration and the production of enzymes responsible for the hydrolysis of ß-lactam antibiotics [ 360 , 361 ]. Research on the potential of nanoparticles to combat biofilms meets the expectations of modern medicine.…”

A Natural Alternative Treatment for Urinary Tract Infections: Itxasol©, the Importance of the Formulation

“…UTIs may be resolved spontaneously or treated with antibiotics [ 25 ]. Antibiotic resistance is a major problem nowadays [ 26 ]; in the European Union alone, it has been reported that annually, there are around 670,000 cases of infections related to multi-drug-resistant bacteria with 37,000 associated deaths, representing an enormous socioeconomic burden [ 27 ]. Regular use of antibiotics is related to nephrotoxicity due to interstitial nephritis, acute tubular necrosis and intratubular crystal deposition, which leads to an impaired kidney function [ 28 ].…”