scholarly journals Cyclic and Acyclic Amine Oxide Alkyl Derivatives as Potential Adjuvants in Antimicrobial Chemotherapy against Methicillin-Resistant Staphylococcus aureus with an MDR Profile

Antibiotics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 952
Author(s):  
Lorenza Fagnani ◽  
Lisaurora Nazzicone ◽  
Fabrizia Brisdelli ◽  
Luisa Giansanti ◽  
Sara Battista ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Blood Cells ◽  
Pathogenic Bacteria ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Amine Oxide ◽  
Therapeutic Option ◽  
Multidrug Resistant ◽  
Methicillin Resistant ◽  
Amphoteric Surfactants

The dramatic intensification of antimicrobial resistance occurrence in pathogenic bacteria concerns the global community. The revitalisation of inactive antibiotics is, at present, the only way to go through this health system crisis and the use of antimicrobial adjuvants is turning out the most promising approach. Due to their low toxicity, eco-friendly characteristics and antimicrobial activity, amphoteric surfactants are good candidates. This study investigated the adjuvant potentialities of commercial acyclic and newly cyclic N-oxide surfactants combined with therapeutically available antibiotics against MDR methicillin-resistant Staphylococcus aureus (MRSA). The safety profile of the new cyclic compounds, compared to commercial surfactants, was preliminarily assessed, evaluating the cytotoxicity on human peripheral mononuclear blood cells and the haemolysis in human red blood cells. The compounds show an efficacious antimicrobial activity strongly related to the length of the carbon atom chain. In drug–drug interaction assays, all surfactants act synergistically, restoring sensitivity to oxacillin in MRSA, with dodecyl acyclic and cyclic derivatives being the most effective. After evaluating the cytotoxicity and considering the antimicrobial action, the most promising compound is the L-prolinol amine-oxide C12NOX. These findings suggest that the combination of antibiotics with amphoteric surfactants is a valuable therapeutic option for topical infections sustained by multidrug-resistant S. aureus.

scholarly journals Fluoroquinolone Metalloantibiotics: A Promising Approach against Methicillin-Resistant Staphylococcus aureus

2020 ◽  
Vol 17 (9) ◽  
pp. 3127 ◽  
Author(s):  
Mariana Ferreira ◽  
Lucinda J. Bessa ◽  
Carla F. Sousa ◽  
Peter Eaton ◽  
Dafne Bongiorno ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Mechanism Of Action ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Synergistic Activity ◽  
Divalent Metal Ions ◽  
Methicillin Resistant ◽  
Force Microscopy

Fluoroquinolones (FQs) are antibiotics commonly used in clinical practice, although nowadays they are becoming ineffective due to the emergence of several mechanisms of resistance in most bacteria. The complexation of FQs with divalent metal ions and phenanthroline (phen) is a possible approach to circumvent antimicrobial resistance, since it forms very stable complexes known as metalloantibiotics. This work is aimed at determining the antimicrobial activity of metalloantibiotics of Cu(II)FQphen against a panel of multidrug-resistant (MDR) clinical isolates and to clarify their mechanism of action. Minimum inhibitory concentrations (MICs) were determined against MDR isolates of Escherichia coli, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA). Metalloantibiotics showed improved antimicrobial activity against several clinical isolates, especially MRSA. Synergistic activity was evaluated in combination with ciprofloxacin and ampicillin by the disk diffusion and checkerboard methods. Synergistic and additive effects were shown against MRSA isolates. The mechanism of action was studied though enzymatic assays and atomic force microscopy (AFM) experiments. The results indicate a similar mechanism of action for FQs and metalloantibiotics. In summary, metalloantibiotics seem to be an effective alternative to pure FQs against MRSA. The results obtained in this work open the way to the screening of metalloantibiotics against other Gram-positive bacteria.

scholarly journals Isolation of Lichens associated Actinomycetes: Determining its antibacterial activity against Multi drug resistant Klebsiella pneumoniae and Methicillin resistant Staphylococcus aureus

2021 ◽  
Vol 23 (06) ◽  
pp. 1489-1509
Author(s):  
VidhyaSri AR ◽  
◽  
Dr. Thamarai Selvi B ◽  
Sanjay Prasad S ◽  
Karkuvelraja R ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pathogenic Bacteria ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Klebsiella Pneumonia ◽  
Methicillin Resistant ◽  
Rrna Sequencing ◽  
New Antibiotics ◽  
Rapid Emergence

The rapid emergence of drug resistance among pathogenic bacteria, especially multidrug-Resistant bacteria, underlines the need to search for new antibiotics. In the present study, actinomycetes were isolated from lichens collected from coconut trees. The actinomycetes were investigated for antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) and Klebsiella pneumonia in order to identify the potential antibiotic producers.MIC was determined and the organism was identified using 16s rRNA sequencing. Crude action extracts showed 11mm and 9mm against MRSA and Klebsiella pneumonia. The isolated actinomycetes were found to be Streptomyces hygro scopicus subspecies. GC-MS analysis identified several novel compounds. Thus, the isolated actinomycetes can be used for the development of new antibiotics for the treatment of MDR infection.

scholarly journals Antimicrobial activity of Rhipsalis baccifera and Drymoglossum piloselloides against Methicillin Resistant Staphylococcus Aureus and Drug Resistant Acinetobacter baumanii.

2021 ◽  
pp. 32-40
Author(s):  
S. D. Kugaperumal ◽  
R. D. De Silva ◽  
T. D. Karunarathne ◽  
C. P. Gunasekara ◽  
D. N. A. W. Samarakoon
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Chronic Wounds ◽  
Multidrug Resistant ◽  
Antibiotic Activity ◽  
Diffusion Method ◽  
Acinetobacter Baumanii ◽  
Methicillin Resistant

Methicillin Resistant Staphylococcus aureus (MRSA) and multidrug-resistant Acinetobacter baumanii are known to cause delayed healing of infections in both acute and chronic wounds. Plants are a natural source of novel antimicrobials and many new drugs are derived from plants, as plants contain phytochemicals that have antimicrobial activity. Sri Lanka is a tropical country with a wide variety of plant species, many of which were identified as possessing medicinal qualities and have been used by traditional medicinal practitioners in the treatment of various diseases and ailments. Dressings made of Rhipsalis baccifera and Drymoglossum piloselloides have been used to treat wounds by Sri Lankan traditional medicine practitioners. This study determined the antibacterial activity of aqueous and methanol extracts of R. baccifera and D. piloselloides against MRSA and Multidrug-resistant A. baumanii. Aqueous and methanolic extractions of both plants were done by maceration. Their antibacterial properties were checked against MRSA and A. baumanii by the well diffusion method. The effectiveness of the extract was further tested against factors like temperature and storage time. R. baccifera (aqueous extract) exhibited antimicrobial properties against MRSA but no activity against A. baumanii. The antibiotic activity against MRSA was increased after two months of storage at 4°C. D. piloselloides exhibited no antibiotic activity against both MRSA and A. baumanii. The methanolic extracts did not demonstrate any antibacterial activity.

scholarly journals The Prevalence of Virulence Determinants and Antibiotic Resistance Patterns in Methicillin—Resistant Staphylococcus aureus in a Nursing Home in Poland

Pathogens ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 427
Author(s):  
Martyna Kasela ◽  
Agnieszka Grzegorczyk ◽  
Bożena Nowakowicz-Dębek ◽  
Anna Malm
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Variable Number Tandem Repeat ◽  
Multidrug Resistant ◽  
Variable Number ◽  
Pulse Field ◽  
Virulence Determinants ◽  
Gene Encoding ◽  
Methicillin Resistant ◽  
Pulse Field Gel Electrophoresis

Nursing homes (NH) contribute to the regional spread of methicillin-resistant Staphylococcus aureus (MRSA). Moreover, residents are vulnerable to the colonization and subsequent infection of MRSA etiology. We aimed at investigating the molecular and phenotypic characteristics of 21 MRSA collected from the residents and personnel in an NH (Lublin, Poland) during 2018. All MRSA were screened for 20 genes encoding virulence determinants (sea-see, eta, etb, tst, lukS-F-PV, eno, cna, ebpS, fib, bbp, fnbA, fnbB, icaADBC) and for resistance to 18 antimicrobials. To establish the relatedness and clonal complexes of MRSA in NH we applied multiple-locus variable-number tandem-repeat fingerprinting (MLVF), pulse field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and staphylococcal cassette chromosome mec (SCCmec) typing. We identified four sequence types (ST) among two clonal complexes (CC): ST (CC22) known as EMRSA-15 as well as three novel STs—ST6295 (CC8), ST6293 (CC8) and ST6294. All tested MRSA were negative for sec, eta, etb, lukS-F-PV, bbp and ebpS genes. The most prevalent gene encoding toxin was sed (52.4%; n = 11/21), and adhesins were eno and fnbA (100%). Only 9.5% (n = 2/21) of MRSA were classified as multidrug-resistant. The emergence of novel MRSA with a unique virulence and the presence of epidemic clone EMRSA-15 creates challenges for controlling the spread of MRSA in NH.

scholarly journals Antimicrobial Metabolites against Methicillin-Resistant Staphylococcus aureus from the Endophytic Fungus Neofusicoccum australe

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1094
Author(s):  
Melissa M. Cadelis ◽  
Soeren Geese ◽  
Benedict B. Uy ◽  
Daniel R. Mulholland ◽  
Shara J. van de Pas ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Natural Products ◽  
Structure Elucidation ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Inhibitory Concentration ◽  
Spectroscopic Methods ◽  
Methicillin Resistant ◽  
Bioassay Guided Fractionation ◽  
Antimicrobial Metabolites

Antimicrobial bioassay-guided fractionation of the endophytic fungi Neofusicoccum australe led to the isolation of a new unsymmetrical naphthoquinone dimer, neofusnaphthoquinone B (1), along with four known natural products (2–5). Structure elucidation was conducted by nuclear magnetic resonance (NMR) spectroscopic methods, and the antimicrobial activity of all the natural products was investigated, revealing 1 to be moderately active towards methicillin-resistant Staphylococcus aureus (MRSA) with a minimum inhibitory concentration (MIC) of 16 µg/mL.

Non-Multidrug-Resistant, Methicillin-Resistant Staphylococcus aureus in a Neonatal Unit

2014 ◽  
Vol 33 (10) ◽  
pp. e252-e259 ◽  
Author(s):  
Cilmara P. Garcia ◽  
Juliana F. Rosa ◽  
Maria A. Cursino ◽  
Renata D. Lobo ◽  
Carla H. Mollaco ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Multidrug Resistant ◽  
Neonatal Unit ◽  
Methicillin Resistant
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