Antimicrobial resistance is an old and silent pandemic. Resistant organisms emerge in parallel with new antibiotics, leading to a major global public health crisis over time. Antibiotic resistance may be due to different mechanisms and against different classes of drugs. These mechanisms are usually found in the same organism, giving rise to multidrug-resistant (MDR) and extensively drug-resistant (XDR) bacteria. One resistance mechanism that is closely associated with the emergence of MDR and XDR bacteria is the efflux of drugs since the same pump can transport different classes of drugs. In Gram-negative bacteria, efflux pumps are present in two configurations: a transmembrane protein anchored in the inner membrane and a complex formed by three proteins. The tripartite complex has a transmembrane protein present in the inner membrane, a periplasmic protein, and a porin associated with the outer membrane. In , one of the main pathogens associated with respiratory tract infections, four main sets of efflux pumps have been associated with antibiotic resistance: MexAB-OprM, MexXY, MexCD-OprJ, and MexEF-OprN. In this review, the function, structure, and regulation of these efflux pumps in and their actions as resistance mechanisms are discussed. Finally, a brief discussion on the potential of efflux pumps in as a target for new drugs is presented.
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http://dx.doi.org/10.3390/ijms232415779 | DOI Listing |
Microb Pathog
January 2025
Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Electronic address:
Following a period of disuse owing to the emergence of multidrug-resistant Gram-negative bacteria, colistin has regained global attention as an antibiotic of last resort. The resurgence in its utilization has led to a concurrent increase in acquired resistance, presenting a significant challenge in clinical treatment. Predominantly, resistance mechanisms involve alterations in the lipid A component of the lipopolysaccharide (LPS) structure.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK.
The global dissemination of pathotypes with multidrug-resistant (MDR) and hypervirulent traits poses a threat to public health. The situation in Armenia is unclear, and we performed a comprehensive characterisation of 48 clinical isolates of , collected from 2018 to 2024. The majority of the isolates (64.
View Article and Find Full Text PDFMicroorganisms
January 2025
State Key Laboratory of Microbial Technology and Institute of Microbial Technology, Shandong University, Qingdao 266237, China.
Phenolic compounds are industrially versatile chemicals that have been successfully produced in microbial cell factories. Unfortunately, most phenolic compounds are highly toxic to cells in specific cellular environments or above a particular concentration because they form a complex with iron and promote hydroxyl radical production in Fenton reactions, resulting in the ferroptosis of cells. Here, we demonstrated that overexpression of efflux pumps and porins, including porins LamB and OmpN, and efflux pumps EmrAB, MdtABC, and SrpB, can enhance phloroglucinol (PG) tolerance by inhibiting the generation of hydroxyl radicals.
View Article and Find Full Text PDFAntibiotics (Basel)
January 2025
Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy.
is considered one of the prioritized ESKAPE microorganisms for the research and development of novel treatments by the World Health Organization, especially because of its remarkable persistence and drug resistance. In this review, we describe how this can be acquired by the enzymatic degradation of antibiotics, target site modification, altered membrane permeability, multidrug efflux pumps, and their ability to form biofilms. Also, the evolution of drug resistance in , which is mainly driven by mobile genetic elements, is reported, with particular reference to plasmid-associated resistance, resistance islands, and insertion sequences.
View Article and Find Full Text PDFAntibiotics (Basel)
January 2025
Institute of Medical Microbiology, Semmelweis University, 1089 Budapest, Hungary.
In this study, the mechanisms implicated in delafloxacin resistance in strains were investigated. Delafloxacin is a novel, broad-spectrum fluoroquinolone that has been approved for clinical application. In our study, 43 strains were assessed, antimicrobial susceptibility testing was performed via the broth microdilution method, and the minimum inhibitory concentration (MIC) values for ciprofloxacin, delafloxacin, levofloxacin, moxifloxacin, ceftazidime, cefotaxime, and imipenem were determined.
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