scholarly journals Molecular determinants of antibiotic resistance in Salmonella enterica antibiotic resistance

2021 ◽  
Author(s):  
A. S. Pavlova ◽  
Yu. A. Bocharova ◽  
K. V. Kuleshov ◽  
A. T. Podkolzin ◽  
I. V. Chebotar
Keyword(s):  
Antibiotic Resistance ◽  
Salmonella Enterica ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Molecular Genetic ◽  
Natural Resistance ◽  
Molecular Diagnostic ◽  
Diagnostic Systems ◽  
Mechanisms Of Resistance ◽  
Genetic Sequencing

Nontyphoid strains of Salmonella enterica pose a great threat to human health. The problem of salmonellosis is aggravated compounded by the progressive spread of antibiotic resistance among clinical and agricultural strains of S. enterica. This literature review summarizes the current knowledge of the mechanisms of antibiotic resistance in S. enterica and illustrates the diversity and complexity of molecular systems providing antibiotic resistance. The spectrum of natural resistance is described and the adaptive (acquired) mechanisms of resistance to representatives of the main classes of antibiotics, including fluoroquinolones, aminoglycosides, tetracyclines, nitrofurans, sulfonamides, fosfomycin and chloramphenicol, are thoroughly characterized. Particular emphasis is placed on the analysis of the molecular genetic mechanisms of S. enterica resistance to representatives of the most important classes of antibiotics — β-lactams, and to reserve antibiotics — polymyxins (colistin). Genetic determinants of resistance, transmitted by a horizontal path route are also described. The review analyzes only those variants of the molecular mechanisms of antibiotic resistance where the clinical significance has been proven by a set of correct genetic (sequencing) and biochemical (confirmation of the spectrum of hydrolyzed β-lactams) studies. The main ways of regulating the expression of antibiotic resistance are also described. Many S. enterica strains exhibit a combination of different mechanisms of antibiotic resistance and have a multiple resistance. The question was raised about the heterogeneity of the distribution of resistance among different groups/serotypes within the S. enterica species. In particular, some clonal complexes with signs of resistance are more successful pathogens in humans and animals. Salmonella, like most other bacteria, exhibit a non-canonical type of antibiotic resistance — biofilm resistance, which is realized through several mechanisms, the main of which are the filtering/sorption capacity of the biofilm matrix and the transformation of biofilm cells into dormant and persistent forms.Despite the fact that the functional significance of the molecular assemblies that determine antibiotic resistance is the same for all enterobacteria, the specification of the mechanisms of resistance in Salmonella is a necessary link for the development of molecular diagnostic systems for assessing the sensitivity to antimicrobial drugs. 

scholarly journals Antibiotic resistance in lactococci and enterococci: phenotypic and molecular-genetic aspects

2017 ◽  
Vol 1 (1) ◽  
pp. 10-17
Author(s):  
Danuta Plotnikava ◽  
Anastasiya Sidarenka ◽  
Galina Novik
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Antibiotic Resistance Genes ◽  
Public Health Problem ◽  
Animal Husbandry ◽  
Resistant Bacteria ◽  
Monitoring And Control ◽  
Bacterial Drug Resistance

Abstract Extensive use of antibiotics in medicine, veterinary practice and animal husbandry has promoted the development and dissemination of bacterial drug resistance. The number of resistant pathogens causing common infectious diseases increases rapidly and creates worldwide public health problem. Commensal bacteria, including lactic acid bacteria of genera Enterococcus and Lactococcus colonizing gastrointestinal and urogenital tracts of humans and animals may act as vehicles of antibiotic resistance genes similar to those found in pathogens. Lactococci and enterococci are widely used in manufacturing of fermented products and as probiotics, therefore monitoring and control of transmissible antibiotic resistance determinants in industrial strains of these microorganisms is necessary to approve their Qualified Presumption of Safety status. Understanding the nature and molecular mechanisms of antibiotic resistance in enterococci and lactococci is essential, as intrinsic resistant bacteria pose no threat to environment and human health in contrast to bacteria with resistance acquired through horizontal transfer of resistance genes. The review summarizes current knowledge concerning intrinsic and acquired antibiotic resistance in Lactococcus and Enterococcus genera, and discusses role of enterococci and lactococci in distribution of this feature.

scholarly journals Antimicrobial Susceptibility and Mechanisms of Resistance in Shigella and Salmonella Isolates from Children under Five Years of Age with Diarrhea in Rural Mozambique

2009 ◽  
Vol 53 (6) ◽  
pp. 2450-2454 ◽  
Author(s):  
Inácio Mandomando ◽  
Dinis Jaintilal ◽  
Maria J. Pons ◽  
Xavier Vallès ◽  
Mateu Espasa ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Nalidixic Acid ◽  
Antimicrobial Susceptibility ◽  
Molecular Mechanisms ◽  
Antimicrobial Agents ◽  
Shigella Flexneri ◽  
Colorimetric Method ◽  
Multidrug Resistant ◽  
Mechanisms Of Resistance ◽  
First Line

ABSTRACT The antimicrobial susceptibility and mechanisms of resistance of 109 Shigella and 40 Salmonella isolates from children with diarrhea in southern Mozambique were assessed. The susceptibility to seven antimicrobial agents was tested by disk diffusion, and mechanisms of resistance were searched by PCR or colorimetric method. A high proportion of Shigella isolates were resistant to chloramphenicol (Chl) (52%), ampicillin (Amp) (56%), tetracycline (Tet) (66%), and trimethoprim-sulfamethoxazole (Sxt) (84%). Sixty-five percent of the isolates were multidrug resistant. Shigella flexneri isolates were more resistant than those of Shigella sonnei to Amp (66% versus 0.0%, P < 0.001) and Chl (61% versus 0.0%, P < 0.001), whereas S. sonnei isolates presented higher resistance to Tet than S. flexneri isolates (93% versus 64%, P = 0.02). Resistance among Salmonella isolates was as follows: Tet and Chl, 15% each; Sxt, 18%; and Amp, 25%. Only 3% of Salmonella isolates were resistant to nalidixic acid (Nal), and none to ciprofloxacin or ceftriaxone (Cro). Among Salmonella isolates, multiresistance was found in 23%. Among Shigella isolates, antibiotic resistance was related mainly to the presence of oxa-1-like β-lactamases for Amp, dfrA1 genes for Sxt, tetB genes for Tet, and Chl acetyltransferase (CAT) activity for Chl. Among Salmonella isolates, resistance was conferred by tem-like β-lactamases for Amp, floR genes and CAT activity for Chl, tetA genes for Tet, and dfrA1 genes for Sxt. Our data show that Shigella isolates are resistant mostly to the most available, inexpensive antibiotics by various molecular mechanisms but remain susceptible to ciprofloxacin, Cro, and Nal, which is the first line for empirical treatment of shigellosis in the country.

scholarly journals Transcriptional Regulation of the Multiple Resistance Mechanisms in Salmonella—A Review

Pathogens ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 801
Author(s):  
Michał Wójcicki ◽  
Olga Świder ◽  
Kamila J. Daniluk ◽  
Paulina Średnicka ◽  
Monika Akimowicz ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Multidrug Resistance ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Foodborne Pathogen ◽  
Resistance Mechanisms ◽  
Global Regulators ◽  
Contaminated Food ◽  
Transcription Activators ◽  
Global And Local

The widespread use of antibiotics, especially those with a broad spectrum of activity, has resulted in the development of multidrug resistance in many strains of bacteria, including Salmonella. Salmonella is among the most prevalent causes of intoxication due to the consumption of contaminated food and water. Salmonellosis caused by this pathogen is pharmacologically treated using antibiotics such as fluoroquinolones, ceftriaxone, and azithromycin. This foodborne pathogen developed several molecular mechanisms of resistance both on the level of global and local transcription modulators. The increasing rate of antibiotic resistance in Salmonella poses a significant global concern, and an improved understanding of the multidrug resistance mechanisms in Salmonella is essential for choosing the suitable antibiotic for the treatment of infections. In this review, we summarized the current knowledge of molecular mechanisms that control gene expression related to antibiotic resistance of Salmonella strains. We characterized regulators acting as transcription activators and repressors, as well as two-component signal transduction systems. We also discuss the background of the molecular mechanisms of the resistance to metals, regulators of multidrug resistance to antibiotics, global regulators of the LysR family, as well as regulators of histone-like proteins.

scholarly journals Mechanisms of antibiotic resistance in Haemophilus parainfluenzae

2017 ◽  
Vol 32 (3) ◽  
pp. 111-114
Author(s):  
Regina E. Abotsi ◽  
Usha Govinden ◽  
Sabiha Y. Essack
Keyword(s):  
Antibiotic Resistance ◽  
Literature Review ◽  
Resistance Genes ◽  
Molecular Mechanisms ◽  
Antibiotic Resistance Genes ◽  
Healthy Individuals ◽  
Mechanisms Of Resistance ◽  
Haemophilus Parainfluenzae ◽  
Life Threatening

Haemophilus parainfluenzae is part of the HACEK group of fastidious bacteria commonly implicated in endocarditis and bacteremia. Previously considered as a normal respiratory, oral and sometimes genitourinary commensal, it has been recognised as a pathogen that can cause life-threatening infections in both immunocompromised and healthy individuals. It has also been reported as a bacterium that can harbor transferable antibiotic resistance genes. This paper presents a literature review on the molecular mechanisms of resistance of H. parainfluenzae to commonly prescribed antibiotics and discusses areas for further research.

Mesophyll conductance: the leaf corridors for photosynthesis

2020 ◽  
Vol 48 (2) ◽  
pp. 429-439 ◽  
Author(s):  
Jorge Gago ◽  
Danilo M. Daloso ◽  
Marc Carriquí ◽  
Miquel Nadal ◽  
Melanie Morales ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Main Role ◽  
Mesophyll Conductance ◽  
Future Studies ◽  
Cell Structures ◽  
Leaf Tissues ◽  
Change Framework ◽  
Chloroplast Stroma

Besides stomata, the photosynthetic CO2 pathway also involves the transport of CO2 from the sub-stomatal air spaces inside to the carboxylation sites in the chloroplast stroma, where Rubisco is located. This pathway is far to be a simple and direct way, formed by series of consecutive barriers that the CO2 should cross to be finally assimilated in photosynthesis, known as the mesophyll conductance (gm). Therefore, the gm reflects the pathway through different air, water and biophysical barriers within the leaf tissues and cell structures. Currently, it is known that gm can impose the same level of limitation (or even higher depending of the conditions) to photosynthesis than the wider known stomata or biochemistry. In this mini-review, we are focused on each of the gm determinants to summarize the current knowledge on the mechanisms driving gm from anatomical to metabolic and biochemical perspectives. Special attention deserve the latest studies demonstrating the importance of the molecular mechanisms driving anatomical traits as cell wall and the chloroplast surface exposed to the mesophyll airspaces (Sc/S) that significantly constrain gm. However, even considering these recent discoveries, still is poorly understood the mechanisms about signaling pathways linking the environment a/biotic stressors with gm responses. Thus, considering the main role of gm as a major driver of the CO2 availability at the carboxylation sites, future studies into these aspects will help us to understand photosynthesis responses in a global change framework.

Molecular Basis and Clinical Aspects of Hereditary Megakaryocyte and Platelet Membrane Glycoprotein Disorders

1996 ◽  
Vol 16 (02) ◽  
pp. 114-138 ◽  
Author(s):  
R. E. Scharf
Keyword(s):  
Genetic Basis ◽  
Molecular Mechanisms ◽  
Molecular Genetic ◽  
Platelet Membrane ◽  
Clinical Aspects ◽  
Membrane Glycoprotein ◽  
Membrane Glycoproteins ◽  
Membrane Expression ◽  
Receptor Complexes ◽  
Platelet Membrane Glycoprotein

SummarySpecific membrane glycoproteins (GP) expressed by the megakaryocyte-platelet system, including GPIa-lla, GPIb-V-IX, GPIIb-llla, and GPIV are involved in mediat-ing platelet adhesion to the subendothelial matrix. Among these glycoproteins, GPIIb-llla plays a pivotal role since platelet aggregation is exclusively mediated by this receptor and its interaction with soluble macromolecular proteins. Inherited defects of the GPIIb-llla or GPIb-V-IX receptor complexes are associated with bleeding disorders, known as Glanzmann's thrombasthenia, Bernard-Soulier syndrome, or platelet-type von Willebrand's disease, respectively. Using immuno-chemical and molecular biology techniques, rapid advances in our understanding of the molecular genetic basis of these disorders have been made during the last few years. Moreover, analyses of patients with congenital platelet membrane glycoprotein abnormalities have provided valuable insights into molecular mechanisms that are required for structural and functional integrity, normal biosynthesis of the glycoprotein complexes and coordinated membrane expression of their constituents. The present article reviews the current state of knowledge of the major membrane glycoproteins in health and disease. The spectrum of clinical bleeding manifestations and established diagnostic criteria for each of these dis-orders are summarized. In particular, the variety of molecular defects that have been identified so far and their genetic basis will be discussed.

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