scholarly journals Staphylococcus aureus Toxins: An Update on Their Pathogenic Properties and Potential Treatments

Toxins ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 677
Author(s):  
Nour Ahmad-Mansour ◽  
Paul Loubet ◽  
Cassandra Pouget ◽  
Catherine Dunyach-Remy ◽  
Albert Sotto ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Health Concern ◽  
Antibiotic Resistant ◽  
Major Health ◽  
Frequent Use ◽  
Wide Range ◽  
Novel Therapeutic Strategies ◽  
High Level ◽  
Resistance Rates ◽  
Human Infections

Staphylococcus aureus is a clinically important pathogen that causes a wide range of human infections, from minor skin infections to severe tissue infection and sepsis. S. aureus has a high level of antibiotic resistance and is a common cause of infections in hospitals and the community. The rising prevalence of community-acquired methicillin-resistant S. aureus (CA-MRSA), combined with the important severity of S. aureus infections in general, has resulted in the frequent use of anti-staphylococcal antibiotics, leading to increasing resistance rates. Antibiotic-resistant S. aureus continues to be a major health concern, necessitating the development of novel therapeutic strategies. S. aureus uses a wide range of virulence factors, such as toxins, to develop an infection in the host. Recently, anti-virulence treatments that directly or indirectly neutralize S. aureus toxins have showed promise. In this review, we provide an update on toxin pathogenic characteristics, as well as anti-toxin therapeutical strategies.

scholarly journals A Putative Cro-Like Repressor Contributes to Arylomycin Resistance in Staphylococcus aureus

2015 ◽  
Vol 59 (6) ◽  
pp. 3066-3074 ◽  
Author(s):  
Arryn Craney ◽  
Floyd E. Romesberg
Keyword(s):  
Staphylococcus Aureus ◽  
Ex Vivo ◽  
Transcriptional Regulator ◽  
Signal Peptidase ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Type I ◽  
Wall Teichoic Acid ◽  
Content Type ◽  
Wide Range

ABSTRACTAntibiotic-resistant bacteria are a significant public health concern and motivate efforts to develop new classes of antibiotics. One such class of antibiotics is the arylomycins, which target type I signal peptidase (SPase), the enzyme responsible for the release of secreted proteins from their N-terminal leader sequences. Despite the essentiality, conservation, and relative accessibility of SPase, the activity of the arylomycins is limited against some bacteria, including the important human pathogenStaphylococcus aureus. To understand the origins of the limited activity againstS. aureus, we characterized the susceptibility of a panel of strains to two arylomycin derivatives, arylomycin A-C16and its more potent analog arylomycin M131. We observed a wide range of susceptibilities to the two arylomycins and found that resistant strains were sensitized by cotreatment with tunicamycin, which inhibits the first step of wall teichoic acid synthesis. To further understand howS. aureusresponds to the arylomycins, we profiled the transcriptional response ofS. aureusNCTC 8325 to growth-inhibitory concentrations of arylomycin M131 and found that it upregulates the cell wall stress stimulon (CWSS) and an operon consisting of a putative transcriptional regulator and three hypothetical proteins. Interestingly, we found that mutations in the putative transcriptional regulator are correlated with resistance, and selection for resistanceex vivodemonstrated that mutations in this gene are sufficient for resistance. The results begin to elucidate howS. aureuscopes with secretion stress and how it evolves resistance to the inhibition of SPase.

scholarly journals Activity of Ceftaroline and Epidemiologic Trends in Staphylococcus aureus Isolates Collected from 43 Medical Centers in the United States in 2009

2011 ◽  
Vol 55 (9) ◽  
pp. 4154-4160 ◽  
Author(s):  
Sandra S. Richter ◽  
Kristopher P. Heilmann ◽  
Cassie L. Dohrn ◽  
Fathollah Riahi ◽  
Andrew J. Costello ◽  
...  
Keyword(s):  
United States ◽  
Staphylococcus Aureus ◽  
The United States ◽  
Surveillance Program ◽  
Content Type ◽  
Type Iv ◽  
Medical Centers ◽  
High Level ◽  
Resistance Rates

ABSTRACTAStaphylococcus aureussurveillance program was initiated in the United States to examine thein vitroactivity of ceftaroline and epidemiologic trends. Susceptibility testing by Clinical and Laboratory Standards Institute broth microdilution was performed on 4,210 clinically significant isolates collected in 2009 from 43 medical centers. All isolates were screened formecAby PCR and evaluated by pulsed-field gel electrophoresis. Methicillin-resistantS. aureus(MRSA) were analyzed for Panton-Valentine leukocidin (PVL) genes and the staphylococcal cassette chromosomemec(SCCmec) type. All isolates had ceftaroline MICs of ≤2 μg/ml with an MIC50of 0.5 and an MIC90of 1 μg/ml. The overall resistance rates, expressed as the percentages of isolates that were intermediate and resistant (or nonsusceptible), were as follows: ceftaroline, 1.0%; clindamycin, 30.2% (17.4% MIC ≥ 4 μg/ml; 12.8% inducible); daptomycin, 0.2%; erythromycin, 65.5%; levofloxacin, 39.9%; linezolid, 0.02%; oxacillin, 53.4%; tetracycline, 4.4%; tigecycline, 0%; trimethoprim-sulfamethoxazole, 1.6%; vancomycin, 0%; and high-level mupirocin, 2.2%. ThemecAPCR was positive for 53.4% of the isolates. The ceftaroline MIC90s were 0.25 μg/ml for methicillin-susceptibleS. aureusand 1 μg/ml for MRSA. Among the 2,247 MRSA isolates, 51% were USA300 (96.9% PVL positive, 99.7% SCCmectype IV) and 17% were USA100 (93.4% SCCmectype II). The resistance rates for the 1,137 USA300 MRSA isolates were as follows: erythromycin, 90.9%; levofloxacin, 49.1%; clindamycin, 7.6% (6.2% MIC ≥ 4 μg/ml; 1.4% inducible); tetracycline, 3.3%; trimethoprim-sulfamethoxazole, 0.8%; high-level mupirocin, 2.7%; daptomycin, 0.4%; and ceftaroline and linezolid, 0%. USA300 is the dominant clone causing MRSA infections in the United States. Ceftaroline demonstrated potentin vitroactivity against recentS. aureusclinical isolates, including MRSA, daptomycin-nonsusceptible, and linezolid-resistant strains.

Opposite effect of vancomycin and D-Cycloserine combination in both vancomycin resistant Staphylococcus aureus and enterococci

2020 ◽  
Vol 367 (8) ◽  
Author(s):  
Abdelhakim Boudrioua ◽  
Yanyan Li ◽  
Axel Hartke ◽  
Caroline Giraud
Keyword(s):  
Staphylococcus Aureus ◽  
Opposite Effect ◽  
Inhibitory Concentration ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Glycopeptide Antibiotic ◽  
Antibiotic Resistant ◽  
Peptidoglycan Biosynthesis ◽  
Vancomycin Resistant ◽  
Type Strains

ABSTRACT The increasing spread of antibiotic resistant bacteria is a major human health concern. The challenging development of new effective antibiotics has led to focus on seeking synergistic antibiotic combinations. Vancomycin (VAN) is a glycopeptide antibiotic used to treat Staphylococcus aureus and enterococci infections. It is targeting D-Alanyl-D-Alanine dimers during peptidoglycan biosynthesis. D-cycloserine (DCS) is a D-Alanine analogue that targets peptidoglycan biosynthesis by inhibiting D-Alanine:D-Alanine ligase (Ddl). The VAN-DCS combination was found to be synergistic in VAN resistant S. aureus strains lacking van genes cluster. We hypothesize that this combination leads to opposite effects in S. aureus and enterococci strains harboring van genes cluster where VAN resistance is conferred by the synthesis of modified peptidoglycan precursors ending in D-Alanyl-D-Lactate. The calculated Fractional Inhibitory Concentration of VAN-DCS combination in a van- vancomycin-intermediate, VanA type, and VanB type strains were 0.5, 5 and 3, respectively. As a result, VAN-DCS combination leads to synergism in van-lacking strains, and to antagonism in strains harboring van genes cluster. The VAN-DCS antagonism is due to a mechanism that we named van-mediated Ddl inhibition bypass. Our results show that antibiotic combinations can lead to opposite effects depending on the genetic backgrounds.

scholarly journals PROFILE OF STAPHYLOCOCCUS AUREUS ISOLATED FROM PATIENTS ADMITTED IN A TERTIARY CARE HOSPITAL WITH ESPECIAL REFERENCE TO METHICILLIN RESISTANCE

2020 ◽  
pp. 1-2
Author(s):  
Asmita Singh ◽  
Anita Pandey ◽  
Amit Singh ◽  
Priyanka Chaturvedi
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Tertiary Care Hospital ◽  
Methicillin Resistance ◽  
Tertiary Care ◽  
Hospital Setting ◽  
Clinical Isolates ◽  
Care Hospital ◽  
Wide Range ◽  
High Level

BACKGROUND: Staphylococcus aureus is a major human pathogen that causes wide range of clinical infections. Methicillin-resistant Staphylococcus aureus(MRSA) is endemic in India and is a dangerous pathogen causing hospital acquired infection leadings to signicant morbidity and mortality. OBJECTIVE:To study the prole of Staphylococcus aureusisolated from patients admitted in a tertiary care hospital. RESULT: Majority of clinical isolates of S.aurueswas obtained from patients of skin and soft tissue infection(54.66%) followed by those suffering from respiratory infection (13.33%), blood stream infection (13.33%) and UTI(8%). S.aureus was predominantly isolated from IPD samples, maximum cases were in the age group of 31-40 years and males outnumbered females. There was predominance of MRSA 112 (74.66%)which showed high level of resistance to penicillin (100%), ciprooxacin (82.14 %), co-trimoxazole (79.46%) and moxioxacin(85.71%). All the clinical isolates of S.aureuswere sensitive to linezolid andvancomycin (MIC <1ugm/ml). CONCLUSIONS: The clinical isolates of S.aureusshowed high level of resistance to various antimicrobial agents which is a signicant nosocomial threat. Surveillance and infection control practices should be carried out to prevent cross transmission of such resistant pathogen within the hospital setting

scholarly journals Antibiotic Resistance Considerations of Importance to Clinical Dermatologists

2017 ◽  
Vol 1 (2) ◽  
pp. 64
Author(s):  
James Del Rosso DO
Keyword(s):  
Antibiotic Resistance ◽  
Acne Vulgaris ◽  
Antibiotic Use ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Topical Antibiotic ◽  
Antibiotic Resistant ◽  
Major Health ◽  
Slow Development ◽  
Formidable Challenge

Antibiotic resistance is a major health concern worldwide as the list of bacterial pathogens that are insensitive to available antibiotics continues to grow in both hospitals and outpatient communities. The slow development of newer antibiotics adds to the formidable challenge that clinicians face with treatment of infections caused by antibiotic-resistant bacteria. This article discusses important caveats related to antibiotic use in dermatology. These include understanding that both topical and oral antibiotics contribute to the emergence and spread of resistant bacteria, that antibiotic monotherapy is to be avoided for treatment of acne vulgaris, that effective treatment of rosacea does not require the use of an antibiotic, that antibiotic therapy in the management of atopic dermatitis is best limited to treatment of an active clinical infection, and that routine post-operative use of a topical antibiotic is not suggested after most office-based dermatologic procedures. By following principles of antibiotic stewardship, dermatologists are major players in the battle against antibiotic resistance.

scholarly journals ANTIBIOTICS PRODUCING BACTERIA ISOLATED FROM FARMLANDS

2019 ◽  
Vol 2 (4) ◽  
pp. 99
Author(s):  
Hammed Abiodun Durojaye ◽  
Georgia Chinemenwa Agu
Keyword(s):  
Staphylococcus Aureus ◽  
Enterococcus Faecalis ◽  
Bacillus Megaterium ◽  
Pathogenic Bacteria ◽  
Antibiotic Production ◽  
Health Concern ◽  
Klebsiella Pneumonia ◽  
Proteus Vulgaris ◽  
Ogun State ◽  
Wide Range

The need for new antibiotics has been highlighted recently with the increasing pace of emergence of drug resistance pathogens. Emerging strains of bacteria resistant to most advanced antibiotics have become issues of very important public health concern. Modification of existing antibiotics with the addition of side chains or other chemical group and genomics based drug targeting have been the preferred method of drug development at the corporate level in recent years. In this regard, soil samples were collected from farmlands located in Ibadan in Oyo state, Ago – Iwoye, and Ikenne in Ogun state, Nigeria. Two putative Streptomyces strains and Bacillus strains isolated from the 16 selected farmland soils were characterized and assessed for antibiotic production and activity against a wide range of bacteria including Klebsiella pneumonia, Serratia marscens, Proteus vulgaris, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Enterococcus faecalis. The extracts of the putative obtained from Streptomyces somaliensis, Streptomyces anulatus, Bacillus megaterium, and Bacillus subtilis showed activities against minimum of 3 and maximum of the 4 of the 7 tested bacteria. Inhibition zones were found to range between 2.0 - 25.0 mm diameters at a concentration of 1ml. The minimum inhibitory concentrations (MICs) of the crude extracts against the tested organisms ranged from 50% and above. Bacillus megaterium, and Streptomyces somaliensis were found to inhibit all the pathogenic bacteria, while S. anulatus was unable to inhibit Proteus vulgaris and Staphylococcus aureus, and B. Subtilis was unable to inhibit Enterococcus faecalis.

scholarly journals Prevalence of qnr Genes among Multidrug Resistance Staphylococcus aureus from Clinical Isolates

2019 ◽  
pp. 1-10
Author(s):  
Abdulrasheed B. Abdu ◽  
Tattfeng Y. Mirabeau
Keyword(s):  
Staphylococcus Aureus ◽  
Low Frequency ◽  
Control Measures ◽  
Clinical Isolates ◽  
Resistance Pattern ◽  
Infection Control Measures ◽  
Study Results ◽  
Polymerase Chain ◽  
High Level ◽  
Human Infections

Objectives: Staphylococcus aureus (S. aureus) is regarded as an important aetiological agent of various human infections. Fluoroquinolones are routinely used in the chemotherapeutic management of these infections; nonetheless, in recent years, a growing rate of resistance to these drugs has been reported worldwide. The aims of this study were to isolate and discover the prevalence of plasmid-mediated (qnrA, qnrB, and qnrS) genes among the quinolone-resistant clinical S. aureus isolates in Bayelsa State, Nigeria. Methods: A total of 25 (31.25%) clinical isolates of S. aureus were collected from hospitalized patients. The bacterial isolates were identified through standard laboratory protocols and further confirmed using the API Staph system (bioMérieux, France) test strips. The antimicrobial susceptibility and minimum inhibitory concentration (MIC) were determined by the standard disk diffusion and serial dilutions methods respectively. Polymerase chain reaction (PCR) was used for detecting qnrA, qnrB, and qnrS genes. Results: Of the 25 S. aureus isolates, 19(76.00%) were resistant to ampicillin-cloxacillin, while 14 (56.00%) each were resistant to norfloxacin and Amoxicillin, 13 (52.00%) each to gentamicin and erythromycin, 11 (44.00%) were resistant to streptomycin, rifampicin and ciprofloxacin, respectively. The resistance pattern among the isolates to chloramphenicol and levofloxacin were 10 (40.00%) and 7 (28.00%) respectively. All the eleven ciprofloxacin resistant were high-level (1000 µg/mL) resistance isolates and only one (9.00%) of these isolates was positive for the qnrB gene. Conclusion: The study results were indicative of the presence of low frequency of qnr genes among the clinical isolates of S. aureus in Yenagoa, indicating that other mechanisms are employed in resisting to these fluoroquinolones. This, however, emphasizes the need for establishing discreet policies associated with infection-control measures in hospital settings.

scholarly journals Relationship Among Antibiotic Residues And Antibacterial Activity Of The Endemic Spurge Honey (Euphorbia Resinifera O. Berg) From Morocco

2020 ◽  
pp. 795
Author(s):  
Rania Benjamaa ◽  
Abdelkarim Moujanni ◽  
Anass Terrab ◽  
Rabiaa Eddoha ◽  
Maryam Benbachir ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Inhibition Zone ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Antibiotic Residues ◽  
Antibiotic Resistant ◽  
Liquid Chromatography Tandem Mass

Antibiotic-resistant bacteria continue to be of major health concern worldwide. In recent years, several reports and scientific articles claim the contamination of honey by antibiotics, detectable concentrations of antibiotic residues in honey are illegal. They, may cause hypersensitivity or resistance to drug therapy in humans, and are perceived by consumers as undesirable. In this sense, the purpose of this work was to examine the antibacterial activity of the Euphorbia resinifera (E. resinifera) honey against Escherichia coli and Staphylococcus aureus in vitro using the well-agar diffusion assay followed by dilution range to obtain more precise minimum inhibitory concentration values. The second aim is to evaluate the presence of antibiotics in honey using a screening test: Evidence InvestigatorTM, an immuno-enzymatic method for detection of 27 antibiotic residues followed by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) for confirmation of suspect samples; in order to assess the relationship between the presence of antibiotic residues and the antibacterial activity of honey. In this study, a total of 37 E. resinifera honey samples were analyzed. The results show that all samples of honey inhibited the growth of bacteria at the dilutions at 50% (v/v); the highest inhibition zone (25.98 ± 0.11 mm) was recorded from sample 5 for Staphylococcus aureus and (13.84 ± 1.10 mm) in sample 17 for Escherichia coli and that 50% (v/v) dilutions showed significant antibacterial effect compared to other dilutions (6.25, 12.5, 25% (v/v)). In all samples, there were no antibiotic residues detected except for one showing the detection of Trimethoprim at 6.48 µg kg-1. Our research is one of the first studies that relate the he relationship between the presence of antibiotic residues and the antibacterial activity of Euphorbia resinifera honey and showed that the antibacterial activity of honey might be due to the high osmotic nature, a low pH, its content of phenolic compounds and hydrogen peroxide and also to its content of methylglyoxal.

scholarly journals Lipid Signaling Modulates the Response to Fumonisin Contamination and Its Source, Fusarium verticillioides, in Maize

2021 ◽  
Vol 12 ◽  
Author(s):  
Laura Righetti ◽  
Chiara Dall’Asta ◽  
Luigi Lucini ◽  
Paola Battilani
Keyword(s):  
Open Field ◽  
High Performance ◽  
Fusarium Verticillioides ◽  
Health Concern ◽  
Lipid Signaling ◽  
Major Health ◽  
Signaling Systems ◽  
Plant Pathogen Interaction ◽  
High Level ◽  
Maize Response

Fumonisin-contaminated maize (Zea mays L.) products are a major health concern because of their toxic effects in humans and animals. Breeding maize for increased mycotoxin resistance is one of the key sustainable strategies for mitigating the effects of fumonisin contamination. Recent studies suggest a link between fumonisin accumulation and plant lipid and oxylipin profiles. However, the data collected so far do not reveal a cause-and-effect relationship. In this study, to decipher the multifactorial nature of mycotoxin resistance and plant–pathogen interaction mechanisms, we examined the oxylipin and complex lipid profiles of two maize hybrids (H21 and H22, the latter showing significantly lower FBs content) grown in the open field in two locations over 3years. Untargeted ultra-high performance liquid chromatography coupled with quadrupole-time-of-flight (UHPLC-Q-TOF), together with chemometrics analysis, successfully distinguished between the two hybrids as having low- and high-level fumonisin contamination. Considering that H21 and H22 were exposed to the same environmental factors, the higher activation of lipid signaling systems in H22 suggests that other routes are enabled in the less susceptible hybrids to limit fumonisin B (FB) accumulation. Our results highlighted the crucial role played by oxylipin and sphingolipid signaling in modulating the complex maize response to F. verticillioides infection. Overall, our results returned a global view on the changes in lipid metabolites related to fumonisin accumulation under open field conditions, and revealed a strong activation of the lipid signaling cascade in maize in the presence of FB1.

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