scholarly journals Factors of Nasopharynx that Favor the Colonization and Persistence of Staphylococcus aureus

2021 ◽  
Author(s):  
Samuel González-García ◽  
Aída Hamdan-Partida ◽  
Anaíd Bustos-Hamdan ◽  
Jaime Bustos-Martínez
Keyword(s):  
Staphylococcus Aureus ◽  
Host Cell ◽  
Defense Mechanisms ◽  
The Other ◽  
World Population ◽  
Anatomical Site ◽  
Methicillin Resistant ◽  
The World ◽  
Cell Components ◽  
Wall Teichoic Acids

Between 30 and 50% of the world population is permanently colonized in some anatomical site by Staphylococcus aureus, although the vast majority are asymptomatic carriers. The nose is its main niche and currently the colonization of S. aureus in the pharynx has become relevant due to the variety of reported carrier rates and the epidemiological importance of the dissemination of Methicillin-resistant S. aureus strains (MRSA) by pharyngeal carriers. For this bacterium to colonize a tissue successfully, it is necessary to establish many interactions with bacterial and host cell components such as bacterial wall teichoic acids (WTA) with the Scavenger SREC-1 host receptor and at the same time evade the defense mechanisms. On the other hand, there are host factors that will facilitate or complicate the colonization or persistence of S. aureus at these sites, such as physiological, genetic, immunological and microbiological factors.

scholarly journals Crystal structures of the components of theStaphylococcus aureusleukotoxin ED

2016 ◽  
Vol 72 (1) ◽  
pp. 113-120 ◽  
Author(s):  
S. Nocadello ◽  
G. Minasov ◽  
L. Shuvalova ◽  
I. Dubrovska ◽  
E. Sabini ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Host Cell ◽  
Crystal Structures ◽  
Cell Types ◽  
Water Soluble ◽  
The Other ◽  
Structural Homology ◽  
Methicillin Resistant ◽  
Structural Variability ◽  
Protein Receptors

Staphylococcal leukotoxins are a family of β-barrel, bicomponent, pore-forming toxins with membrane-damaging functions. These bacterial exotoxins share sequence and structural homology and target several host-cell types. Leukotoxin ED (LukED) is one of these bicomponent pore-forming toxins thatStaphylococcus aureusproduces in order to suppress the ability of the host to contain the infection. The recent delineation of the important role that LukED plays inS. aureuspathogenesis and the identification of its protein receptors, combined with its presence inS. aureusmethicillin-resistant epidemic strains, establish this leukocidin as a possible target for the development of novel therapeutics. Here, the crystal structures of the water-soluble LukE and LukD components of LukED have been determined. The two structures illustrate the tertiary-structural variability with respect to the other leukotoxins while retaining the conservation of the residues involved in the interaction of the protomers in the bipartite leukotoxin in the pore complex.

scholarly journals Methicillin-Resistant Staphylococci and Macrococci at the Interface of Human and Animal Health

Toxins ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 61
Author(s):  
Karsten Becker
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Animal Health ◽  
Methicillin Resistant ◽  
Global Impact ◽  
The World

The global impact of methicillin-resistant Staphylococcus aureus (MRSA) clonal lineages on human and animal health continues, even considering the decreasing MRSA rates in some parts of the world [...]

scholarly journals Structural Comparison of Three Types of Staphylococcal Cassette Chromosome mec Integrated in the Chromosome in Methicillin-Resistant Staphylococcus aureus

2001 ◽  
Vol 45 (5) ◽  
pp. 1323-1336 ◽  
Author(s):  
Teruyo Ito ◽  
Yuki Katayama ◽  
Kazumi Asada ◽  
Namiko Mori ◽  
Kanae Tsutsumimoto ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Integration Site ◽  
Direct Repeats ◽  
Methicillin Resistant ◽  
Genetic Elements ◽  
The World ◽  
Different Types ◽  
Junction Points ◽  
Mrsa Strains ◽  
Staphylococcal Cassette Chromosome

ABSTRACT The β-lactam resistance gene mecA ofStaphylococcus aureus is carried by a novel mobile genetic element, designated staphylococcal cassette chromosome mec(SCCmec), identified in the chromosome of a Japanese methicillin-resistant S. aureus (MRSA) strain. We now report identification of two additional types ofmecA-carrying genetic elements found in the MRSA strains isolated in other countries of the world. There were substantial differences in the size and nucleotide sequences between the elements and the SCCmec. However, new elements shared the chromosomal integration site with the SCCmec. Structural analysis of the new elements revealed that they possessed all of the salient features of the SCCmec: conserved terminal inverted repeats and direct repeats at the integration junction points, conserved genetic organization around the mecA gene, and the presence of cassette chromosome recombinase (ccr) genes responsible for the movements of SCCmec. The elements, therefore, were considered to comprise the SCCmec family of staphylococcal mobile genetic elements together with the previously identified SCCmec. Among 38 epidemic MRSA strains isolated in 20 countries, 34 were shown to possess one of the three typical SCCmec elements on the chromosome. Our findings indicated that there are at least three distinct MRSA clones in the world with different types of SCCmec in their chromosome.

scholarly journals Prevalence of Panton-Valentine leukocidin genes in community-associated methicillin-resistant Staphylococcus aureus in the district of Pomoravlje

2016 ◽  
Vol 73 (3) ◽  
pp. 256-260 ◽  
Author(s):  
Ljiljana Petrovic-Jeremic ◽  
Nada Kuljic-Kapulica ◽  
Elizabeta Ristanovic ◽  
Dragana Josic ◽  
Zorica Lepsanovic
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Clinical Laboratory ◽  
Meca Gene ◽  
Latex Agglutination ◽  
The Other ◽  
Methicillin Resistant ◽  
Standard Polymerase Chain Reaction ◽  
Panton Valentine Leukocidin ◽  
Valentine Leukocidin

Background/Aim. Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains appear to have rapidly disseminated among population in the community without established risk factors for MRSA worldwide. Panton-Valentine leukocidin (PVL) is a cytolytic toxin, encoded by the lukF-PV and lukF-PV genes. PVL may be the key toxin responsible for enhanced virulence of CA-MRSA. The aim of this study was to detect the genes encoding PVL in CA-MRSA isolates from healthy people from the District of Pomoravlje. Methods. We took throat and nose swabs from healthy, employed persons with mandatory sanitary examinations and analyzed the presence of MRSA, between January 2011 and December 2012 in the District of Pomoravlje. Susceptibility of isolated strains to cefoxitin was investigated by using disc diffusion according to the recommendation of CLSI (Clinical Laboratory Standard Institute), and by E test. The presence of penicillin-binding protein 2a (PBP2a) in Staphylococci was detected using latex agglutination Slidex ?MRSA Detection test. The gold standard, polymerase chain reaction (PCR) assay, was used for detection of mecA gene and PVL gene, and typing of SCCmec region. Results. Our investigation showed that staphylococcal carrier state was present in 2.58% of 52,910 throat and nasal swabs, and in 50 of them (3.67%) MRSA was isolated. Among these MRSA, 2 (4%) isolates were PVL-positive. Conclusion. The prevalence of CAMRSA and the presence of PVL gene among healthy, employed population in the District of Pomoravlje were low. The values obtained in this study show that, our region is not significantly different from the other parts of our country, nor from the other European countries.

scholarly journals Copper Resistance Promotes Fitness of Methicillin-Resistant Staphylococcus aureus during Urinary Tract Infection

mBio ◽  
2021 ◽  
Author(s):  
Panatda Saenkham-Huntsinger ◽  
Amanda N. Hyre ◽  
Braden S. Hanson ◽  
George L. Donati ◽  
L. Garry Adams ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Urinary Tract Infection ◽  
Antibiotic Resistance ◽  
Urinary Tract ◽  
Tract Infection ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Copper Resistance ◽  
Methicillin Resistant ◽  
The World ◽  
Infectious Condition

Urinary tract infection (UTI) is an extremely common infectious condition affecting people throughout the world. Increasing antibiotic resistance in pathogens causing UTI threatens our ability to continue to treat patients in the clinics.

Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in Kyiv Surgical Hospital (Ukraine)

2017 ◽  
Vol 1 (2) ◽  
pp. 73-83
Author(s):  
A.G. Salmanov ◽  
O.M. Verner
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Susceptibility ◽  
Fusidic Acid ◽  
The Other ◽  
Antibiotics Resistance ◽  
Methicillin Resistant ◽  
Surgical Department ◽  
Epidemiologic Surveillance ◽  
Total Prevalence ◽  
Vitek 2

Objective — to determine the prevalence of methicillin-resistant strains of Staphylococcus aureus, isolated from patients different departments in Kyiv Surgical Hospital. Materials and methods. Between June 2015 and December 2015, a total of 128 S. aureus isolates were collected from the pus samples of the patients with SSI in a surgical hospital in Kyiv, Ukraine. The identification and antimicrobial susceptibility of the cultures were determined, using automated microbiology analyzer VITEK 2 Compact (bioMerieux, France). Susceptibility to antibiotics was determined using VITEK 2 AST-P580 card (bioMerieux, France), which included 20 antibiotics (benzylpenicillin, oxacyllin, cefoxitin, gentamycin, tobramycin, levofloxacin, moxifloxacin, erythromycin, clindamycin, linezolid, teicoplanin, vancomycin, tetracycline, tigecycline, fosfomicin, nitrofurantoin, fusidic acid, mupirocin, rifampicin, and trimethoprim/ sulphamethoxazole) and a cefoxitin test, designed for detection of staphylococci resistance to methicillin. Interpretative criteria were those suggested by the Clinical and Laboratory Standards Institute (CLSI). Results and discussion. Based on antimicrobial susceptibility analysis, the most active antibiotics found in the study were linezolid, tigecycline, and mupirocin, showing growth inhibition of 100 % strains tested. Susceptibility to the other antimicrobials was also on a high level: 99 % of strains were found susceptible to nitrofurantoin and trimethoprim/sulphamethoxazole, 98 % — to fusidic acid, 97 % — to moxifloxacin, 96 % — to teicoplanin, 95 % — to vancomycin and fosfomicin, 93 % — to gentamycin, and 92 % — to tobramycin. Susceptibility to levofloxacin (89 %), tetracycline (88 %), rifampin (87 %), erythromycin (84 %), and clindamycin (79 %) was observed to be some lower. Research of MRSA prevalence in Kyiv Surgical Hospital (Ukraine) shown, that 11 % of staphylococci strains, isolated from patients having nosocomial infections (SSI), had multiple resistance to antibiotics. Resistance S. aureus to oxacyllin came up to 19 %. Further, 35.7 % of MRSA strains were resistant only to the group of beta-lactamic antibiotics, while the rest — also to the other classes of antibiotics. Conclusions. MRSA in surgical hospital, being a subject of the research is considered to be a serious therapeutic and epidemiologic problem. Total prevalence of MRSA in hospital was evaluated as 19 %, varying in every surgical department studied. Antibiotics revealed the most effective for treatment of MRSA infections were linezolid, mupirocin, tigecycline, vancomycine, teicoplanin, moxifloxacin, nitrofurantoin, fusidic acid, and trimethoprim/sulphamethoxazole. Taking into account the constant changes and significant differences of the S. aureus resistance levels observed in various regions, the constant monitoring of antibiotic resistance to antimicrobials in every in-patient medical institution is required and on the base of the local obtained results to elaborate the hospital record sheets. Antibiotics application tactics should be determined in accordance with the local data of resistance to them in each surgical inpatient institution. The system of epidemiologic surveillance over microbial resistance should be established on the local, regional, and national levels.

Needs for Food: Are We Asking Too Much?

1998 ◽  
Author(s):  
J. C. Waterlow
Keyword(s):  
Royal Society ◽  
Point Of View ◽  
The Other ◽  
World Population ◽  
The Past ◽  
Agricultural Efficiency ◽  
Geometrical Progression ◽  
The World ◽  
Friedrich Engels ◽  
Agriculture And Food

The Royal Society has in recent years taken a great interest in the growth of the world’s population and has been represented at the two big international congresses on this subject, in Delhi and in Cairo (Graham-Smith, 1994). According to U.N. projections, in 20 year’s time the world population will be between 7.5 and 8.5 billion (Demeny, 1996). There does not seem to be much controversy about these figures. On the other hand, when it comes to the question of whether it will be possible to feed these 8 billion people, opinions diverge widely between optimists and pessimists. McCalla (1995), the director of the Agriculture and Natural Resources Department of the World Bank, in a very illuminating discussion of the controversy, has said, “The economists are always wrong,” presumably because they have to deduce future trends from those of the past. It seemed to us that the best way to make a useful contribution is to look at the subject and assess the possibilities from an objective scientific point of view. The Royal Society has done this twice in the past, with two discussion meetings: one on Agricultural Efficiency (Cooke et al., 1977) and the other on Technology in the 1990s: Agriculture and Food (Blaxter and Fowden, 1985). Now, 10 years on, it is time to have another go, widening the scope of the recent discussion meeting “Land Resources: On the Edge of the Malthusion Precipice?” The late Kenneth Blaxter, in a scries of lectures called “People, Food and Resources,” published in 1986, recalled a quotation from Friedrich Engels, writing in 1844 about the Malthusian dilemma: “Science advances in proportion to the knowledge bequeathed to it by the previous generation and thus under the most ordinary conditions grows in geometrical progression — and what is impossible for science?” (my italics).

scholarly journals Structure-based discovery of a small-molecule inhibitor of methicillin-resistant Staphylococcus aureus virulence

2020 ◽  
Vol 295 (18) ◽  
pp. 5944-5959 ◽  
Author(s):  
Jie Liu ◽  
Lina Kozhaya ◽  
Victor J. Torres ◽  
Derya Unutmaz ◽  
Min Lu
Keyword(s):  
Staphylococcus Aureus ◽  
Host Cell ◽  
Cell Attachment ◽  
Host Cell Membrane ◽  
Methicillin Resistant ◽  
Molecule Inhibitor ◽  
Membrane Perforation ◽  
Host Cell Attachment ◽  
Mrsa Strains

The rapid emergence and dissemination of methicillin-resistant Staphylococcus aureus (MRSA) strains poses a major threat to public health. MRSA possesses an arsenal of secreted host-damaging virulence factors that mediate pathogenicity and blunt immune defenses. Panton–Valentine leukocidin (PVL) and α-toxin are exotoxins that create lytic pores in the host cell membrane. They are recognized as being important for the development of invasive MRSA infections and are thus potential targets for antivirulence therapies. Here, we report the high-resolution X-ray crystal structures of both PVL and α-toxin in their soluble, monomeric, and oligomeric membrane-inserted pore states in complex with n-tetradecylphosphocholine (C14PC). The structures revealed two evolutionarily conserved phosphatidylcholine-binding mechanisms and their roles in modulating host cell attachment, oligomer assembly, and membrane perforation. Moreover, we demonstrate that the soluble C14PC compound protects primary human immune cells in vitro against cytolysis by PVL and α-toxin and hence may serve as the basis for the development of an antivirulence agent for managing MRSA infections.

scholarly journals Efficacy of Azithromycin in a Mouse Pneumonia Model against Hospital-Acquired Methicillin-Resistant Staphylococcus aureus

2019 ◽  
Vol 63 (9) ◽  
Author(s):  
Yu Yamashita ◽  
Kentaro Nagaoka ◽  
Hiroki Kimura ◽  
Masaru Suzuki ◽  
Satoshi Konno ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Protein A ◽  
Lavage Fluid ◽  
Suppressive Effect ◽  
The Other ◽  
Staphylococcal Protein A ◽  
Methicillin Resistant ◽  
Content Type

ABSTRACT The use of macrolides against pneumonia has been reported to improve survival; however, little is known about their efficacy against methicillin-resistant Staphylococcus aureus (MRSA) pneumonia. In this study, we investigated the effect of azithromycin (AZM) and compared it with that of vancomycin (VCM) and daptomycin (DAP) in a murine model of MRSA pneumonia. Mice were infected with MRSA by intratracheal injection and then treated with AZM, VCM, or DAP. The therapeutic effect of AZM, in combination or not with the other drugs, was compared in vivo, whereas the effect of AZM on MRSA growth and toxin mRNA expression was evaluated in vitro. In vivo, the AZM-treated group showed significantly longer survival and fewer bacteria in the lungs 24 h after infection than the untreated group, as well as the other anti-MRSA drug groups. No significant decrease in cytokine levels (interleukin-6 [IL-6] and macrophage inflammatory protein-2 [MIP-2]) in bronchoalveolar lavage fluid or toxin expression levels (α-hemolysin [Hla] and staphylococcal protein A [Spa]) was observed following AZM treatment. In vitro, AZM suppressed the growth of MRSA in late log phase but not in stationary phase. No suppressive effect against toxin production was observed following AZM treatment in vitro. In conclusion, contrary to the situation in vitro, AZM was effective against MRSA growth in vivo in our pneumonia model, substantially improving survival. The suppressive effect on MRSA growth at the initial stage of pneumonia could underlie the potential mechanism of AZM action against MRSA pneumonia.

scholarly journals Chemical Innovation in Plant Nutrition in a Historical Continuum from Ancient Greece and Rome until Modern Times

2016 ◽  
Vol 21 (1-2) ◽  
pp. 29-43 ◽  
Author(s):  
Jacek Antonkiewicz ◽  
Jan Łabętowicz
Keyword(s):  
Agricultural Production ◽  
Plant Nutrition ◽  
Ancient Greece ◽  
Environmental Problems ◽  
The Other ◽  
Environmental Knowledge ◽  
Geometric Progression ◽  
World Population ◽  
Modern Times ◽  
The World

AbstractThis monograph aims to present how arduously views on plant nutrition shaped over centuries and how the foundation of environmental knowledge concerning these issues was created. This publication also presents current problems and trends in studies concerning plant nutrition, showing their new dimension. This new dimension is determined, on one hand, by the need to feed the world population increasing in geometric progression, and on the other hand by growing environmental problems connected with intensification of agricultural production.

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