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 Blue and red light photoemitters as approach to inhibit Staphylococcus aureus and Pseudomonas aeruginosa growth

2022 ◽  
Vol 82 ◽  
Author(s):  
I. D. C. Galo ◽  
R. P. Prado ◽  
W. G. Dos Santos
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Visible Light ◽  
Blue Light ◽  
Bacterial Infections ◽  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Red Light ◽  
High Rate

Abstract The ability of pathogenic bacteria acquire resistance to the existing antibiotics has long been considered a dangerous health risk threat. Currently, the use of visible light has been considered a new approach to treat bacterial infections as an alternative to antibiotics. Herein, we investigated the antimicrobial effect of two range of visible light, blue and red, on Staphylococcus aureus and Pseudomonas aeruginosa, two pathogenic bacterial commonly found in healthcare settings-acquired infections and responsible for high rate of morbidity and mortality. Bacterial cultures were exposed to blue or red light (470 nm and 660 nm) provided by light-emitting diodes - LED. The fluencies and irradiance used for blue and red light were 284.90 J/cm2, 13.19 mW/cm2 and 603.44 J/cm2, 27.93 mW/cm2 respectively. Different experimental approaches were used to determine the optimal conditions of light application. Only exposure to blue light for 6 hours was able to inhibit about 75% in vitro growth of both bacterial species after 24 hours. The surviving exposed bacteria formed colonies significantly smaller than controls, however, these bacteria were able to resume growth after 48 hours. Blue light was able to inhibit bacterial growth upon inoculation in both saline solution and BHI culture medium. We can conclude that blue light, but not red light, is capable of temporarily retarding the growth of gram negative and gram positive bacteria.

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.

scholarly journals Uji Daya Hambat Air Perasan Buah Jeruk Nipis (Citrus aurantifolia s.) Terhadap Pertumbuhan Bakteri Staphylococcus Aureus Secara In Vitro

2013 ◽  
Vol 2 (1) ◽  
pp. 05 ◽  
Author(s):  
Abdul Razak ◽  
Aziz Djamal ◽  
Gusti Revilla
Keyword(s):  
Staphylococcus Aureus ◽  
Wound Healing ◽  
Contact Time ◽  
Experimental Methods ◽  
Control Group ◽  
Control Group Design ◽  
Citrus Aurantifolia ◽  
Group Design ◽  
Growth Of Bacteria

AbstrakJeruk Nipis (Citrus aurantifolia S.) merupakan salah satu tanaman obat keluarga yang banyak terdapat ditengah masyarkat dan banyak digunakan sebagai ramuan tradisional. Bagian yang sering digunakan adalah air perasannya, dengan salah satu manfaat dapat digunakan untuk menghilangkan jerawat serta penyembuhan luka agar tidak terjadi abses. Jerawat dan abses pada luka merupakan salah satu infeksi yang disebabkan oleh bakteri Staphylococcus aureus.Tujuan Penelitian ini adalah untuk mengetahui daya hambat air perasan buah jeruk nipis (Citrus aurantifolia S.) terhadap pertumbuhan bakteri Staphylococcus aureus secara invitro. Penelitian dilakukan dengan metoda eksperimental laboratorium dengan desain postest only control group design yang dilakukan di Laboratorium Mikrobiologi Fakultas Kedokteran Universitas Andalas.Hasil penelitian menunjukan bahwa air perasan buah jeruk nipis memiliki daya hambat terhadap pertumbuhan bakteri Staphylococcus aureus dengan berbagai konsentrasi yaitu 25%, 50%, 75%, dan 100% dan terdapat pengaruh lama kontak terhadap pertumbuhan bakteri dimana bakteri tidak tumbuh seteleh kontak 5 menit pertama dan diikuti menit-menit berikutnya dengan air perasan buah jeruk nipis konsentrasi 100%. Jadi, semakin tinggi konsentrasi air perasan buah jeruk nipis dan semakin lama kontak dengan bakteri Staphylococcus aureus maka daya hambatnya semakin baik.Kata kunci: Uji Daya Hambat, Air Perasan Buah Jeruk Nipis, Staphylococcus aureus.Abstract Lime (Citrus aurantifolia S.) is kind of family’s herbal medicine, most using in the community is widely used as a traditional herb. The most common used part is the lime fruit squeeze with one of the function is used for removing acne and wound healing to prevent the form of abscess. Pimples and abscesses of the wound is one of the infections caused by the bacterium Staphylococcus aureus.The purpose of this study was to determine the inhibition of lime fruit (Citrus aurantifolia S.) squeeze towards the growth of the bacteria Staphylococcus aureus in vitro condition. The study was conducted with laboratory experimental methods to the design of control group design postest only performed at the Laboratory of Microbiology Faculty of Medicine, University of Andalas.The results showed that the lime fruit (Citrus aurantifolia S.) squeeze has the ability to inhibite the bacterial growth of Staphylococcus aureus with various concentrations of 25%, 50%, 75%, and 100% and there is the effect of contact time on the growth of bacteria which the bacteria do not grow after contact the first 5 minutes and the next minute followed by lime fruit squeeze with 100% concentration lime fruit squeeze. Thus, the higher the concentration of lime fruit squeeze and the longer the contact with the bacteria Staphylococcus aureus is the better towards.Keywords:Inhibition test, The Lime Fruit Squeeze, Staphylococcus Aureus.

scholarly journals Efficacy of Bacteriophages Against Staphylococcus aureus Isolates from Bovine Mastitis

2020 ◽  
Vol 13 (3) ◽  
pp. 35 ◽  
Author(s):  
Isabel Titze ◽  
Tatiana Lehnherr ◽  
Hansjörg Lehnherr ◽  
Volker Krömker
Keyword(s):  
Staphylococcus Aureus ◽  
Host Range ◽  
Bacterial Infections ◽  
Plaque Assay ◽  
Bovine Milk ◽  
Bovine Mastitis ◽  
Raw Milk ◽  
Pasteurized Milk

The lytic efficacy of bacteriophages against Staphylococcus aureus isolates from bovine milk was investigated in vitro, regarding possible applications in the therapy of udder inflammation caused by bacterial infections (mastitis). The host range of sequenced, lytic bacteriophages was determined against a collection of 92 Staphylococcus (S.) aureus isolates. The isolates originated from quarter foremilk samples of clinical and subclinical mastitis cases. A spot test and a subsequent plaque assay were used to determine the phage host range. According to their host range, propagation and storage properties, three phages, STA1.ST29, EB1.ST11, and EB1.ST27, were selected for preparing a bacteriophage mixture (1:1:1), which was examined for its lytic activity against S. aureus in pasteurized and raw milk. It was found that almost two thirds of the isolates could be lysed by at least one of the tested phages. The bacteriophage mixture was able to reduce the S. aureus germ density in pasteurized milk and its reduction ability was maintained in raw milk, with only a moderate decrease compared to the results in pasteurized milk. The significant reduction ability of the phage mixture in raw milk promotes further in vivo investigation.

scholarly journals 569. Evaluation of a Povidone-Iodine Preparation for Nasal Decolonization of Methicillin-Resistant Staphylococcus aureus

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S269-S269
Author(s):  
Hussein Abou Ghaddara ◽  
Jennifer Cadnum ◽  
Y Karen Ng Wong ◽  
Curtis Donskey
Keyword(s):  
Staphylococcus Aureus ◽  
Povidone Iodine ◽  
Perioperative Period ◽  
Control Group ◽  
Single Application ◽  
Methicillin Resistant ◽  
Dosing Intervals ◽  
And Control ◽  
Emergence Of Resistance

Abstract Background Mupirocin is commonly used for nasal decolonization of Staphylococcus aureus, but it has limitations including frequent emergence of resistance and non-adherence due to the need for repeated applications. Povidone-iodine is increasingly used as an alternative for nasal decolonization because it has a low propensity for emergence of resistance and rapid in vitro antibacterial activity. However, limited data are available on the microbiological efficacy of povidone-iodine for suppression of nasal S. aureus. Methods We compared the effectiveness of a single application or 5 days of twice daily application of a commercial 10% povidone-iodine preparation vs. phosphate-buffered saline for a reduction in nasal MRSA in methicillin-resistant S. aureus (MRSA)-colonized patients (9–11 per treatment group). Nasal swabs were collected for quantitative culture of MRSA before and at 1, 6, 12 and 24 hours after the single application or before each dose for the 5-day regimen. Analysis of variance was used to compare MRSA colony counts in povidone iodine vs. control patients. Results The concentrations of MRSA in the nares were similar for povidone-iodine and control group patients prior to treatment. As shown in the figure, the single application of povidone-iodine resulted in a statically significant reduction in nasal MRSA in comparison to controls at 2 and 6 hours after treatment (P10 colonies per swab). Conclusion Our findings suggest that single preoperative applications povidone-iodine could be useful for short-term suppression of S. aureus during the perioperative period. Additional studies are needed to evaluate the efficacy of the povidone-iodine preparation for MRSA decolonization when used at more frequent dosing intervals or in combination with chlorhexidine bathing. Disclosures All authors: No reported disclosures.

scholarly journals In Vitro Evaluation of CBR-2092, a Novel Rifamycin-Quinolone Hybrid Antibiotic: Studies of the Mode of Action in Staphylococcus aureus

2008 ◽  
Vol 52 (7) ◽  
pp. 2313-2323 ◽  
Author(s):  
Gregory T. Robertson ◽  
Eric J. Bonventre ◽  
Timothy B. Doyle ◽  
Qun Du ◽  
Leonard Duncan ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Rna Polymerase ◽  
Mode Of Action ◽  
Bacterial Infections ◽  
Dna Gyrase ◽  
Topoisomerase Iv ◽  
Dna Topoisomerase ◽  
Resistant Variant ◽  
Proven Efficacy

ABSTRACT Rifamycins have proven efficacy in the treatment of persistent bacterial infections. However, the frequency with which bacteria develop resistance to rifamycin agents restricts their clinical use to antibiotic combination regimens. In a program directed toward the synthesis of rifamycins with a lower propensity to elicit resistance development, a series of compounds were prepared that covalently combine rifamycin and quinolone pharmacophores to form stable hybrid antibacterial agents. We describe mode-of-action studies with Staphylococcus aureus of CBR-2092, a novel hybrid that combines the rifamycin SV and 4H-4-oxo-quinolizine pharmacophores. In biochemical studies, CBR-2092 exhibited rifampin-like potency as an inhibitor of RNA polymerase, was an equipotent (balanced) inhibitor of DNA gyrase and DNA topoisomerase IV, and retained activity against a prevalent quinolone-resistant variant. Macromolecular biosynthesis studies confirmed that CBR-2092 has rifampin-like effects on RNA synthesis in rifampin-susceptible strains and quinolone-like effects on DNA synthesis in rifampin-resistant strains. Studies of mutant strains that exhibited reduced susceptibility to CBR-2092 further substantiated RNA polymerase as the primary cellular target of CBR-2092, with DNA gyrase and DNA topoisomerase IV being secondary and tertiary targets, respectively, in strains exhibiting preexisting rifampin resistance. In contrast to quinolone comparator agents, no strains with altered susceptibility to CBR-2092 were found to exhibit changes consistent with altered efflux properties. The combined data indicate that CBR-2092 may have potential utility in monotherapy for the treatment of persistent S. aureus infections.

scholarly journals In VitroStudies Indicate a High Resistance Potential for the Lantibiotic Nisin in Staphylococcus aureus and Define a Genetic Basis for Nisin Resistance

2011 ◽  
Vol 55 (5) ◽  
pp. 2362-2368 ◽  
Author(s):  
Katy L. Blake ◽  
Chris P. Randall ◽  
Alex J. O'Neill
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Fold Increase ◽  
Peptide Antibiotics ◽  
Uncharacterized Protein ◽  
Content Type ◽  
Development Of Resistance ◽  
Genes Encoding ◽  
Bacterial Fitness

ABSTRACTLantibiotics such as nisin (NIS) are peptide antibiotics that may have a role in the chemotherapy of bacterial infections. A perceived benefit of lantibiotics for clinical use is their low propensity to select resistance, although detailed resistance studies with relevant bacterial pathogens are lacking. Here we examined the development of resistance to NIS inStaphylococcus aureus, establishing that mutants, including small-colony variants, exhibiting substantial (4- to 32-fold) reductions in NIS susceptibility could be selected readily. Comparative genome sequencing of a single NISrmutant exhibiting a 32-fold increase in NIS MIC revealed the presence of only two mutations, leading to the substitutions V229G in the purine operon repressor, PurR, and A208E in an uncharacterized protein encoded by SAOUHSC_02955. Independently selected NISrmutants also harbored mutations in the genes encoding these products. Reintroduction of these mutations into theS. aureuschromosome alone and in combination revealed that SAOUHSC_02955(A208E) made the primary contribution to the resistance phenotype, conferring up to a 16-fold decrease in NIS susceptibility. Bioinformatic analyses suggested that this gene encodes a sensor histidine kinase, leading us to designate it “nisin susceptibility-associated sensor (nsaS).” Doubling-time determinations and mixed-culture competition assays between NISrand NISsstrains indicated that NIS resistance had little impact on bacterial fitness, and resistance was stable in the absence of selection. The apparent ease with whichS. aureuscan develop and maintain NIS resistancein vitrosuggests that resistance to NIS and other lantibiotics with similar modes of action would arise in the clinic if these agents are employed as chemotherapeutic drugs.

Teratogenicity of Staphylococcus aureus L-forms using a mouse whole-embryo culture model

2013 ◽  
Vol 62 (5) ◽  
pp. 677-682
Author(s):  
Yong Liu ◽  
Xiang Zhu ◽  
Feng-ling Yu ◽  
Xiao-ming Kong ◽  
Na Lin ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Growth And Development ◽  
Mouse Embryos ◽  
Head Length ◽  
Control Group ◽  
Whole Embryo Culture ◽  
Crown Rump Length ◽  
Gram Staining ◽  
Pass Through

Our previous studies have suggested that Staphylococcus aureus L-forms are able to pass through the placental barrier of mice from the maternal side to the fetal body and affect fetal growth and development, but little is known about the direct influence of S. aureus L-forms on embryos during the critical period of organogenesis. Mouse embryos at gestational day 8.5 were cultured in vitro for 48 h with 0, 50, 100, 200 or 400 c.f.u. S. aureus L-forms ml−1. At the end of the culture period, the mouse embryos were assessed morphologically for viability, growth and development. Bacteriological and immunohistochemical staining were used to determine the existence of S. aureus L-forms in embryonic tissues. We found that both crown–rump length and head length of mouse embryos exposed to S. aureus L-forms at a concentration of 50 c.f.u. ml−1 were reduced. When the mouse embryos were exposed to 100, 200 or 400 c.f.u. S. aureus L-forms ml−1, the total morphological score, number of somites, dry embryo weight, yolk sac diameter, crown–rump length and head length were significantly lower than those of the control group. With the increased concentration of S. aureus L-forms in the culture medium, there were fewer normally developed embryos and more embryos with abnormalities or retardation in growth. S. aureus L-forms detected by Gram-staining and immunohistochemical detection of antigen were found in the tissues of embryos infected by S. aureus L-forms. These data suggest that S. aureus L-forms exert a direct teratogenic effect on cultured mouse embryos in vitro.

scholarly journals Phage φAB6-Borne Depolymerase Combats Acinetobacter baumannii Biofilm Formation and Infection

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 279
Author(s):  
Md. Shahed-Al-Mahmud ◽  
Rakesh Roy ◽  
Febri Gunawan Sugiokto ◽  
Md. Nazmul Islam ◽  
Ming-Der Lin ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Bacterial Infections ◽  
Capsular Polysaccharide ◽  
Foley Catheter ◽  
Inhibition Zone ◽  
Control Group ◽  
Bacterial Cells ◽  
Bacterial Lawn

Biofilm formation is one of the main causes of increased antibiotic resistance in Acinetobacter baumannii infections. Bacteriophages and their derivatives, such as tail proteins with depolymerase activity, have shown considerable potential as antibacterial or antivirulence agents against bacterial infections. Here, we gained insights into the activity of a capsular polysaccharide (CPS) depolymerase, derived from the tailspike protein (TSP) of φAB6 phage, to degrade A. baumannii biofilm in vitro. Recombinant TSP showed enzymatic activity and was able to significantly inhibit biofilm formation and degrade formed biofilms; as low as 0.78 ng, the inhibition zone can still be formed on the bacterial lawn. Additionally, TSP inhibited the colonization of A. baumannii on the surface of Foley catheter sections, indicating that it can be used to prevent the adhesion of A. baumannii to medical device surfaces. Transmission and scanning electron microscopy demonstrated membrane leakage of bacterial cells treated with TSP, resulting in cell death. The therapeutic effect of TSP in zebrafish was also evaluated and the results showed that the survival rate was significantly improved (80%) compared with that of the untreated control group (10%). Altogether, we show that TSP derived from φAB6 is expected to become a new antibiotic against multi-drug resistant A. baumannii and a biocontrol agent that prevents the formation of biofilms on medical devices.

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