scholarly journals In Vitro Inhibition of Staphylococcus aureus subsp. aureus (ATCC® 6538™) by Artemether-Lumefantrine Tablets: A Comparative Study of Three Dosage Strengths

2018 ◽  
Vol 12 (1) ◽  
pp. 397-403
Author(s):  
Opoku Solomon ◽  
Nyanor Isaac
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Inhibitory Concentration ◽  
Drug Resistant ◽  
Active Inhibitor ◽  
Staphylococcus Infections ◽  
Agar Dilution ◽  
Broth Macrodilution ◽  
Antibacterial Chemotherapy

Purpose: Antibiotics are progressively failing in the fight against infections due to S. aureus because the bacterium has an outstanding ability to acquire multi-antibiotic resistance and become resistant to most antibiotics. Multi-drug resistant S. aureus poses a major threat to the foundation upon which standard antibacterial chemotherapy stands, hence the need to consider non-antibiotic solutions to manage invasive bacterial infections. This study investigated the inhibitory activities of three dosage strengths of artemether-lumefantrine tablets against Staphylococcus aureus subsp. aureus (ATCC® 6538™) and determined the minimum concentrations of the tablets that are able to completely inhibit growth of the bacterium in vitro. Methods: The agar dilution and broth macrodilution techniques were used to determine the susceptibility of the Staphylococcus aureus subsp. aureus (ATCC® 6538™) strain to artemether-lumefantrine 20/120mg, 40/240mg and 80/480mg tablets. Results: The most active inhibitor was artemether-lumefantrine 80/480mg tablet with a minimum inhibitory concentration value of 2.5mg/mL while artemether-lumefantrine 20/120mg and 40/240mg tablets exhibited moderate but equal activities against the test strain. Conclusions: The study has revealed that artemether-lumefantrine, an antimalarial drug, also has anti-staphylococcal properties and inhibits S. aureus in vitro. This study presents the first report on the in vitro activity of artemether-lumefantrine tablet against S. aureus and suggests the need to consider it as an alternative in the treatment of staphylococcus infections.

scholarly journals Antimicrobial and Antihypercholesterolemic Activities of Pulicaria gnaphalodes

Dose-Response ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 155932582090485 ◽  
Author(s):  
Syed Ali Raza Naqvi ◽  
Syed Muhammad Ali Shah ◽  
Laiba Kanwal ◽  
Muhammad Saeed ◽  
Atta-ul-Haq ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Bacterial Infections ◽  
Inhibitory Concentration ◽  
Methanol Extract ◽  
Ethanol Extract ◽  
Alternative Therapies ◽  
Zone Of Inhibition

Multidrug resistance has increased globally in the communities. Bacterial infections associated with health care have weakened the existing antimicrobial therapy and demand the search for alternative therapies. In the present investigation, the medicinal plant Pulicaria gnaphalodes from Quetta, Pakistan, has been screened for antimicrobial potential. In vitro antimicrobial efficacy of P gnaphalodes extracts (methanol and ethanol) was quantitatively evaluated on the basis of zone of inhibition against different bacteria and minimum inhibitory concentration (MIC). In vivo, antihypercholesterolemic activity is determined in different rat groups. The results of the study indicated that the ethanol extract of P gnaphalodes showed maximum zone of inhibition for Bacillus subtilis of 12.1 ± 1.1 mm from all others. The methanol extract showed maximum zone of inhibition for Staphylococcus aureus of 11.9 ± 1.0 mm and rifampicin showed maximum zone of inhibition of 23.1 ± 0.9 mm. The results of ethanol and methanol extract of P gnaphalodes against different bacteria revealed that this plant has greater antimicrobial activity. However, the plant extract shows nonsignificant antihypercholesterolemic activity. The extract of this plant can be utilized as medicine to inhibit several infections caused by some bacterial pathogens found in human body.

scholarly journals Bacteriocins of Non-aureus Staphylococci Isolated from Bovine Milk

2017 ◽  
Vol 83 (17) ◽  
Author(s):  
Domonique A. Carson ◽  
Herman W. Barkema ◽  
Sohail Naushad ◽  
Jeroen De Buck
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Genome Mining ◽  
Bovine Milk ◽  
Gene Clusters ◽  
Antibiotic Use ◽  
Content Type ◽  
Treatment And Prevention ◽  
Whole Genomes

ABSTRACT Non-aureus staphylococci (NAS), the bacteria most commonly isolated from the bovine udder, potentially protect the udder against infection by major mastitis pathogens due to bacteriocin production. In this study, we determined the inhibitory capability of 441 bovine NAS isolates (comprising 26 species) against bovine Staphylococcus aureus. Furthermore, inhibiting isolates were tested against a human methicillin-resistant S. aureus (MRSA) isolate using a cross-streaking method. We determined the presence of bacteriocin clusters in NAS whole genomes using genome mining tools, BLAST, and comparison of genomes of closely related inhibiting and noninhibiting isolates and determined the genetic organization of any identified bacteriocin biosynthetic gene clusters. Forty isolates from 9 species (S. capitis, S. chromogenes, S. epidermidis, S. pasteuri, S. saprophyticus, S. sciuri, S. simulans, S. warneri, and S. xylosus) inhibited growth of S. aureus in vitro, 23 isolates of which, from S. capitis, S. chromogenes, S. epidermidis, S. pasteuri, S. simulans, and S. xylosus, also inhibited MRSA. One hundred five putative bacteriocin gene clusters encompassing 6 different classes (lanthipeptides, sactipeptides, lasso peptides, class IIa, class IIc, and class IId) in 95 whole genomes from 16 species were identified. A total of 25 novel bacteriocin precursors were described. In conclusion, NAS from bovine mammary glands are a source of potential bacteriocins, with >21% being possible producers, representing potential for future characterization and prospective clinical applications. IMPORTANCE Mastitis (particularly infections caused by Staphylococcus aureus) costs Canadian dairy producers $400 million/year and is the leading cause of antibiotic use on dairy farms. With increasing antibiotic resistance and regulations regarding use, there is impetus to explore bacteriocins (bacterially produced antimicrobial peptides) for treatment and prevention of bacterial infections. We examined the ability of 441 NAS bacteria from Canadian bovine milk samples to inhibit growth of S. aureus in the laboratory. Overall, 9% inhibited growth of S. aureus and 58% of those also inhibited MRSA. In NAS whole-genome sequences, we identified >21% of NAS as having bacteriocin genes. Our study represents a foundation to further explore NAS bacteriocins for clinical use.

Simultaneous exposure to intracellular and extracellular photosensitizers for the treatment of Staphylococcus aureus infections

2021 ◽  
Author(s):  
Sydney L. Drury ◽  
Anderson R. Miller ◽  
Clare L. Laut ◽  
Alec B. Walter ◽  
Monique R. Bennett ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Near Infrared ◽  
Antimicrobial Photodynamic Therapy ◽  
Biological Processes ◽  
Drug Resistant ◽  
Soft Tissue Infections ◽  
Positive Bacterium ◽  
Human Monoclonal Antibodies ◽  
Simultaneous Exposure

Staphylococcus aureus is a serious threat to public health due to the rise of antibiotic resistance in this organism, which can prolong or exacerbate skin and soft tissue infections (SSTIs). Methicillin-resistant S. aureus is a Gram-positive bacterium and a leading cause of SSTIs. As such, many efforts are underway to develop therapies that target essential biological processes in S. aureus . Antimicrobial photodynamic therapy is effective alternative to antibiotics, therefore we developed an approach to simultaneously expose S. aureus to intracellular and extracellular photoactivators. A near infrared photosensitizer was conjugated to human monoclonal antibodies (mAbs) that target the S. aureus Isd heme acquisition proteins. Additionally, the compound VU0038882 was developed to increase photoactivatable porphyrins within the cell. Combinatorial PDT treatment of drug-resistant S. aureus exposed to VU0038882 and conjugated anti-Isd mAbs proved to be an effective antibacterial strategy in vitro and in a murine model of SSTIs.

scholarly journals In VitroAntistaphylococcal Effects ofEmbelia schimperiExtracts and Their Component Embelin with Oxacillin and Tetracycline

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Johana Rondevaldova ◽  
Olga Leuner ◽  
Alemtshay Teka ◽  
Ermias Lulekal ◽  
Jaroslav Havlik ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Medicinal Plants ◽  
Bacterial Infections ◽  
Inhibitory Concentration ◽  
Developed Countries ◽  
Positive Interactions ◽  
Fractional Inhibitory Concentration ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Broth Microdilution Method

Bacterial infections are in less-developed countries traditionally treated by remedies prepared from medicinal plants.Embelia schimperi(Vatke) is a plant used as a taenicide or disinfectant in Ethiopia, very often taken mixed with another plant species. In the present study, we examined two extracts prepared from seeds and twigs with leaves ofE. schimperiand its main present secondary metabolite embelin for their antibacterial combinatory effect with oxacillin and tetracycline against sensitive and resistantStaphylococcus aureusstrains. Minimum inhibitory concentrations were determined through the broth microdilution method, whereas the combinatory effect was evaluated through fractional inhibitory concentration sum (ΣFIC) indices. Results show many positive interactions and synergy occurring in embelin and oxacillin combinations against 4 out of 9 strains (ΣFIC 0.203–0.477) and for embelin and tetracycline combination against 3 out of 9 strains (ΣFIC 0.400–0.496). Moreover, the resistance to oxacillin has been overcome in 2 strains and to tetracycline in 3 strains. According to our knowledge, this is the first study showing antimicrobial combinatory effect ofE. schimperias well as of embelin. These findings can be used for the further research targeted on the development of new antistaphylococcal agents.

In-Vitro Studies on the Sensitivity of Staphylococcus aureus to Some Ethno-Medicinal Preparations Sold around Kano, Nigeria

2011 ◽  
Vol 4 (1) ◽  
pp. 22-25 ◽  
Author(s):  
M Bashir ◽  
I Yusuf ◽  
AS Kutama
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Test Organism ◽  
Ethanolic Extract ◽  
Screening Tests ◽  
Phytochemical Screening ◽  
Herbal Preparations

Five traditional herbal preparations were sampled between May-June, 2009 in Kano. The samples were investigated for invitro antibacterial activities against clinical isolates of Staphylococcus aureus. Likewise, phytochemical screening tests were conducted to determine some of the phytochemicals present in the ethanolic and water extracts of the samples. Various concentrations of the extracts were prepared using serial doubling dilutions (5000=l/ml, 2500=g/ml, 1250=g/ml, 625=g/ml and 312.5=g/ml). All the test extracts showed slight antibacterial activity against the test organism, with ethanolic extract of sample E having the highest zone diameter of inhibition, while sample H had the lowest diameter of inhibition. The standard antibiotic disc (Gentamicin) had demonstrated the highest activity on the test organisms. The results of the Phytochemical screening revealed the presence of steroid in all the samples, tannin in samples A, C, D and E, reducing sugars in sample A, D and E respectively. The result of the minimum inhibitory concentration (MIC) was found to be above 312.5=g/ml for samples C, D and E. Keywords: Staphylococcus aureus, Herbal preparations, antibacterial activity, Phytochemical screening and minimum inhibitory concentration.

scholarly journals Enhanced Antibacterial Activity of Meropenem against Extensively Drug-Resistant Acinetobacter baumannii by Myrtaceae Plant Extracts

2020 ◽  
Vol 17 (11) ◽  
pp. 1168-1176
Author(s):  
Dennapa SAELOH ◽  
Monton VISUTTHI ◽  
Marisa LEEHA ◽  
Surasak LIMSUWAN ◽  
Supayang Piyawan VORAVUTHIKUNCHAI
Keyword(s):  
Acinetobacter Baumannii ◽  
Bacterial Infections ◽  
Inhibitory Concentration ◽  
Inhibitory Effect ◽  
Drug Resistant ◽  
Microdilution Method ◽  
Extensively Drug Resistant ◽  
Resistant Phenotype ◽  
Bacterial Growth Inhibition ◽  
Mic Value

Acinetobacter baumannii (A. baumannii) has been known as a major cause of nosocomial bacterial infections worldwide. The bacteria are increasingly associated with a broad spectrum of antibiotic resistance, and this has become a widespread concern in a variety of hospitals.Antibiotic development and alternative treatment have become priorities for the treatment of bacterial infections.This study investigated the efficacy of meropenem in combination with five ethanolic extracts of plants in Myrtaceae against extensively drug-resistant (XDR) A. baumannii. The resistant phenotype was previously determined by microdilution method. XDR-A. baumannii strains showed resistance to meropenem with the minimum inhibitory concentration (MIC) in a range of 16 - 128 µg/mL, whereas the MIC value of all extracts, including Calistemon lancealatus, Eucalyptus citridora, Rhodomytus tomentasa, Syzygium cumini, and Xanthortemon chrysanthus, was over 1,000 µg/mL. Interestingly, all extracts potentiated the activity of the antibiotic by reducing the MIC values of the antibiotic. Xanthortemon chrysanthus extract displayed excellent synergism against the bacteria by decreasing the MIC value of the drug greater than 8-fold. In addition, the extract, at concentrations of 31.25, 62.5, 125, 250, 500, and 1,000 µg/mL, obviously increased the inhibitory effect of meropenem (1/4´MIC) against A. baumannii. The percentage of bacterial growth inhibition by combination was 87.9, 88.8, 91.8, 93.6, 99.9, and 100, respectively. The results supported that the extract could improve the activity of ineffective antibiotics against drug-resistant pathogens.Therefore, the findings may serve as therapeutic options for XDR-A. baumannii infections in the future.

scholarly journals Imaging Sensitive and Drug-Resistant Bacterial Infection with [11C]-TMP: In Vitro and First-in-Human Evaluation

2021 ◽  
Author(s):  
Iris K Lee ◽  
Daniel A Jacome ◽  
Joshua K Cho ◽  
Vincent Tu ◽  
Anthony Young ◽  
...  
Keyword(s):  
Bacterial Infection ◽  
Mammalian Cells ◽  
Bacterial Infections ◽  
The Body ◽  
Response Monitoring ◽  
Drug Resistant ◽  
Bacterial Strains ◽  
Critical Question ◽  
In Vitro Uptake

Recently, several molecular imaging strategies have developed to image bacterial infections in humans. Nuclear approaches, specifically positron emission tomography (PET), affords sensitive detection and the ability to non-invasively locate infections deep within the body. Two key radiotracer classes have arisen: metabolic approaches targeting bacterial specific biochemical transformations, and antibiotic-based approaches that have inherent selectivity for bacteria over mammalian cells. A critical question for clinical application of antibiotic radiotracers is whether resistance to the template antibiotic abrogates specific uptake, thus diminishing the predictive value of the diagnostic test. We recently developed small-molecule PET radiotracers based on the antibiotic trimethoprim (TMP), including [11C]-TMP, and have shown their selectivity for imaging bacteria in preclinical models. Here, we measure the in vitro uptake of [11C]-TMP in pathogenic susceptible and drug-resistant bacterial strains. Both resistant and susceptible bacteria showed similar in vitro uptake, which led us to perform whole genome sequencing of these isolates to identify the mechanisms of TMP resistance that permit retained radiotracer binding. By interrogating these isolate genomes and a broad panel of previously sequenced strains, we reveal mechanisms where uptake or binding of TMP radiotracers can potentially be maintained despite the annotation of genes conferring antimicrobial resistance. Finally, we present several examples of patients with both TMP-sensitive and drug-resistant infections in our first-in-human experience with [11C]-TMP. This work underscores the ability of an antibiotic radiotracer to image bacterial infection in patients, which may allow insights into human bacterial pathogenesis, infection diagnosis, and antimicrobial response monitoring.

scholarly journals Staphylococcus aureus growth delay after exposure to low fluencies of blue light (470 nm)

2020 ◽  
Author(s):  
I. D. C. Galo ◽  
B. E. De Lima ◽  
T. G. Santos ◽  
A. Braoios ◽  
R. P. Prado ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Blue Light ◽  
Bacterial Infections ◽  
Growth Delay ◽  
Control Group ◽  
Prolonged Incubation ◽  
Bacterial Cultures ◽  
Experimental Approaches ◽  
Prolonged Hospital

Abstract Antibiotic resistance is one of the greatest challenges to treat bacterial infections worldwide, leading to increase in medical expenses, prolonged hospital stay and increased mortality. The use of blue light has been suggested as an innovative alternative to overcome this problem. In this study we analyzed the antibacterial effect of blue light using low emission parameters on Staphylococcus aureus cultures. In vitro bacterial cultures were used in two experimental approaches. The first approach included single or fractionated blue light application provided by LED emitters (470 nm), with the following fluencies: 16.29, 27.16 and 54.32 J/cm2. For the second approach a power LED (470 nm) was used to deliver 54.32 J/cm2 fractionated in 3 applications. Our results demonstrated that bacterial cultures exposed to fractionated blue light radiation exhibited significantly smaller sizes colonies than the control group after 24 h incubation, however the affected bacteria were able to adapt and continue to proliferate after prolonged incubation time. We could conclude that the hypothetical clinical use of low fluencies of blue light as an antibacterial treatment is risky, since its action is not definitive and proves to be ineffective at least for the strain used in this study.

scholarly journals Antibacterial activity of Taxodium ascendens Diterpenes against Methicillin-resistant Staphylococcus aureus

2014 ◽  
Vol 9 (8) ◽  
pp. 1934578X1400900 ◽  
Author(s):  
Courtney M. Starks ◽  
Vanessa L. Norman ◽  
Russell B. Williams ◽  
Matt G. Goering ◽  
Stephanie M. Rice ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Bacterial Infections ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Clinical Isolates ◽  
Drug Resistant ◽  
Methicillin Resistant

One new and seven known diterpenes were identified from an antibacterial chromatographic fraction of Taxodium ascendens. Of these, demethylcryptojaponol (2), 6-hydroxysalvinolone (3), hydroxyferruginol (4), and hinokiol (5) demonstrated potent activity against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). These compounds represent a class of synthetically accessible compounds that could be further developed for treatment of drug-resistant bacterial infections.

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