scholarly journals Antimicrobial Photodynamic Therapy in the Control of Pseudomonas syringae pv. actinidiae Transmission by Kiwifruit Pollen

2020 ◽  
Vol 8 (7) ◽  
pp. 1022
Author(s):  
Margarida M. Lopes ◽  
Maria Bartolomeu ◽  
Ana T. P. C. Gomes ◽  
Etelvina Figueira ◽  
Ricardo Pinto ◽  
...  

Pseudomonas syringae pv. actinidiae (Psa) is a phytopathogen responsible for bacterial canker in kiwifruit plants and can be disseminated through pollen. This study aimed to evaluate the effectiveness of antimicrobial photodynamic therapy (aPDT) in the inactivation of Psa on kiwifruit pollen using New Methylene Blue (NMB) and Methylene Blue (MB) in the presence/absence of potassium iodide (KI). Pollen germination assays were also performed to evaluate if it was affected by aPDT. Higher reduction of Psa was achieved using NMB (5.0 μM) combined with KI (100 mM) in vitro (ca. 8 log CFU mL−1 after 90 min of irradiation), while NMB alone promoted a lower reduction (3.7 log CFU mL−1). The most efficient NMB concentration with KI was used to study the photodynamic efficiency of MB (5.0 μM). MB with KI photo-inactivated Psa more efficiently than NMB, causing the same bacterial reduction (ca. 8 log CFU mL−1) in half the irradiation time (45 min). Therefore, MB was selected for the subsequent ex vivo aPDT assays in pollen. Almost all the Psa cells added artificially to the pollen (3.2 log CFU mL−1) were photo-inactivated (3.1 log CFU mL−1), whereas aPDT had a low effect on pollen natural microorganisms. When KI was added, a significant increase in aPDT effectiveness was observed (4.5 log CFU mL−1). No negative effects were observed in the pollen germination after aPDT. The results show aPDT is an effective and safe method to Psa inactivation on kiwifruit pollen, and MB use is a promising alternative in the control of Psa transmission.

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 869
Author(s):  
Beatriz Müller Nunes Souza ◽  
Juliana Guerra Pinto ◽  
André Henrique Correia Pereira ◽  
Alejandro Guillermo Miñán ◽  
Juliana Ferreira-Strixino

Staphylococccus aureus is a ubiquitous and opportunistic bacteria associated with high mortality rates. Antimicrobial photodynamic therapy (aPDT) is based on the application of a light source and a photosensitizer that can interact with molecular oxygen, forming Reactive Oxygen Species (ROS) that result in bacterial inactivation. This study aimed to analyze, in vitro, the action of aPDT with Photodithazine® (PDZ) in methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) strains. The strains were incubated with PDZ at 25, 50, 75, and 100 mg/L for 15 min and irradiated with fluences of 25, 50, and 100 J/cm2. The internalization of PDZ was evaluated by confocal microscopy, the bacterial growth by counting the number of colony-forming units, as well as the bacterial metabolic activity post-aPDT and the production of ROS. In both strains, the photosensitizer was internalized; the production of ROS increased when the aPDT was applied; there was a bacterial reduction compared to the control at all the evaluated fluences and concentrations; and, in most parameters, it was obtained complete inactivation with significant difference (p < 0.05). The implementation of aPDT with PDZ in clinical strains of S. aureus has resulted in its complete inactivation, including the MRSA strains.


2016 ◽  
Vol 5 (3) ◽  
Author(s):  
Teresita Spezzia-Mazzocco ◽  
Susana A. Torres-Hurtado ◽  
Julio Cesar Ramírez-San-Juan ◽  
Rubén Ramos-García

2021 ◽  
Vol 49 ◽  
Author(s):  
Marcus Vinícius Alves da Silva ◽  
Manoel Luiz Ferreira ◽  
Ana Flávia Ribeiro Machado Michel ◽  
Thiago Santos Ribeiro ◽  
Vinícius De Oliveira Costa Souza ◽  
...  

Background: Otitis is a severe inflammation of the skin of the auditory canal which can impact animals of all ages. In sheep, this disease can occur in isolated cases or in the entire flock. Laser photobiomodulation can be used in combination with medication or as single therapy and the effects are analgesia, modulation of the inflammatory process, edema reduction, tissue restoration and stimulation of local microcirculation. Antimicrobial photodynamic therapy stands out as a promising alternative to antimicrobial drugs for the treatment of localized infections. This study aimed to report the use of laser phototherapies on a sheep with bacterial otitis.Case: A case of bacterial otitis in a 4-year-old sheep, Dorper, was treated at the Veterinary Hospital of the State University of Santa Cruz. In the anamnesis, the owner reported that the patient presented crusts in the auricular pavilions, and had been medicated with oxytetracycline 20%, administered intramuscularly, for two days and the crusts cleaned with iodine 10%, but the animal did not present clinical improvement. On physical examination, the animal presented constant head swaying, edema of the ears, otalgia, enlarged parotid lymph nodes and ear wounds. No ear discharge was observed, and the initial diagnosis was aural hematoma. The treatment prescribed was laser photobiomodulation for three consecutive days. The lesions were irradiated with a diode laser with a power of 0.1 W, irradiance of 3.5 W/cm2, continuous emission, spot area of 0.028 cm2, wavelength of 808 nm, energy of 4J/point, and fluency/point of 142.8J/cm2, with seven points on the external surface and four points on the internal surface of both ears. Two points were also targeted on the parotid lymph nodes with infrared laser (λ = 808 nm), with energy of 2J/point. On the fourth day of hospitalization, there was a reduction in lesions, decreased edema and absence of pain and on the sixth day of hospitalization, the patient presented mucopurulent otorrhea. The material from the auricular pavilions was collected for cytological examination, confirming the clinical diagnosis of bacterial otitis. Two sessions of Antimicrobial Photodynamic Therapy (aPDT) were performed with an interval of 48 hours, with application of 0.01 % methylene blue, pre-irradiation time of five minutes and irradiation with diode laser with a power of 0.1 W, 660 nm wavelength and 9J/point energy. On the 10 th day after the start of the treatment, there was no pain, healing of ear wounds, and no otorrhea. An additional photobiomodulation session was performed on the unhealed wounds in the auditory canal with red laser (λ = 660nm), on 5 points with an energy of 1J/point. On the 15th day, the left ear was healed and the right ear presented otorrhea, and a further session of aPDT was performed. On the 17th day after starting treatment there was no secretion and all lesions were healed. The patient was subsequently monitored for one month, showing no change or relapse.Discussion: Laser photobiomodulation treatment and antimicrobial photodynamic therapy were efficient in treating bacterial otitis without the use of antibiotics, promoting clinical improvement and patient well-being, making it an alternative to conventional treatment. After searches on the Pubmed, Scielo and Escopus databases using photobiomodulation and antimicrobial photodynamic therapy in sheep otitis as descriptors, this is believed to be the first report on the use of laser phototherapy in sheep otitis. Further studies are needed to establish the dosimetry and frequency of the sessions, as, besides considering animal well-being, this species is an excellent model for human experimentation.


Antibiotics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 98 ◽  
Author(s):  
Òscar Gulías ◽  
Giselle McKenzie ◽  
Miquel Bayó ◽  
Montserrat Agut ◽  
Santi Nonell

The emergence of multidrug-resistant bacteria is a growing problem and alternative therapies are being sought to effectively address this issue. The aim of this study is to assess a range of Escherichia coli strains’ susceptibility to Methylene Blue-mediated antimicrobial photodynamic therapy and determine if this is affected by their antibiotic-resistance profile. Two reference and twenty-four uropathogenic clinical E. coli strains were used in this study. All were tested in vitro for antimicrobial susceptibility against sixteen antibiotics. Strains underwent photodynamic treatments using the photosensitizer Methylene Blue with red light and tested in both planktonic and biofilm state. It was found that reference strain ATCC 25922 was susceptible to all tested antibiotics whereas reference strain ATCC 35218 showed resistance only to Ampicillin. With the exception of strains number 16 and 22, all of the isolated strains were multidrug-resistant according to the criteria established by the European Centre for Disease Prevention and Control and the Centre for Disease Control and Prevention, where acquired non-susceptibility to at least one agent in three or more antimicrobial categories is outlined. Photodynamic therapy induced more than 3 log10 colony-forming units’ reduction to all strains in planktonic state. Whereas when tested in biofilm state, two and a half times the original dose of methylene blue was necessary to cause a 3 log10 antimicrobial effect. There were statistically significant differences in susceptibility among the strains tested in both the planktonic and biofilm experiments. Nevertheless, antimicrobial photodynamic therapy could inactivate all multidrug-resistant strains in the planktonic and biofilm state.


Author(s):  
Daliana-Emanuela Mocuta (Bojoga) ◽  
Mariana Ioana Miron ◽  
Elena Hogea ◽  
Cornelia Muntean ◽  
Darinca Carmen Todea

Background: In orthodontic therapy, the enamel around brackets is very susceptible to bacterial-plaque retention, which represents a risk factor for dental tissues. The aim of this study was to evaluate the effect of methylene blue and a chlorophyllin–phycocyanin mixture, used with and without light activation, in contrast with a 2% chlorhexidine solution, on Streptococcus mutans colonies. Methods: Twenty caries-free human extracted teeth were randomized into five groups. A Streptococcus mutans suspension was inoculated on teeth in groups B, C, D, and E (A was the positive-control group). Bacterial colonies from groups C, D, and E (B was the negative-control group) were subjected to photosensitizers and 2% chlorhexidine solution. For groups C and D, a combined therapy consisting of photosensitizer and light activation was performed. The Streptococcus mutans colonies were counted, and smears were examined with an optical microscope. Two methods of statistical analysis, unidirectional analysis of variance and the Tukey–Kramer test, were used to evaluate the results. Results: A statistically significant reduction in bacterial colonies was detected after the combined therapy was applied for groups C and D, but the most marked bacterial reduction was observed for group D, where a laser-activated chlorophyll–phycocyanin mixture was used. Conclusions: Photodynamic therapy in combination with methylene blue or chlorophyllin–phycocyanin mixture sensitizers induces a statistically significant decrease in the number of bacterial colonies.


2020 ◽  
Vol 19 (10) ◽  
pp. 1332-1343
Author(s):  
Lisa Karner ◽  
Susanne Drechsler ◽  
Magdalena Metzger ◽  
Ara Hacobian ◽  
Barbara Schädl ◽  
...  

The batericidal effects of antimicrobial photodynamic therapy (aPDT), using methylene blue as a photosensitizer and pulsed red LED light for activation, were tested in various environments in vitro and in a wound model in mice infected with a fecal bacterial suspension.


Author(s):  
Ashwin Kumar Tulasi ◽  
Anil Goud Kandhula ◽  
Ravi Krishna Velupula

Topiramate is a second-generation antiepileptic drug used in partial, generalized seizures as an oral tablet. Oral route of administration is most convenient but shows delayed absorption. Moreover, in emergency cases, parenteral administration is not possible as it requires medical assistance. Hence, the present study was aimed to develop topiramate mucoadhesive nanoparticles for intranasal administration using ionotropic gelation method. The developed nanoparticles were evaluated for physico-chemical properties like particle size, zeta potential, surface morphology, drug content, entrapment efficiency, in vitro drug release, mucoadhesive strength, and ex vivo permeation studies in excised porcine nasal mucosa. Optimized nanoparticle formulation (T9) was composed oil mucoadhesive agent (Chitosan 1% w/w), cross linking polymer (TPP) and topiramate 275mg, 100mg and 4% respectively. It showed particle size of 350nm, high encapsulation efficacy and strong mucoadhesive strength. In vitro drug diffusion of optimized formulation showed 95.12% release of drug after 180min. Ex-vivo permeation of drug across nasal mucosa was   88.05 % after 180min. Nasocilial toxicity studies showed optimized formulation did not damage the nasal mucosa. Thus, the intranasal administration of topiramate using chitosan can be a promising alternative for brain targeting and the treatment of epilepsy.


2021 ◽  
Vol 14 (7) ◽  
pp. 603
Author(s):  
Vanesa Pérez-Laguna ◽  
Isabel García-Luque ◽  
Sofía Ballesta ◽  
Antonio Rezusta ◽  
Yolanda Gilaberte

The present review covers combination approaches of antimicrobial photodynamic therapy (aPDT) plus antibiotics or antifungals to attack bacteria and fungi in vitro (both planktonic and biofilm forms) focused on those microorganisms that cause infections in skin and soft tissues. The combination can prevent failure in the fight against these microorganisms: antimicrobial drugs can increase the susceptibility of microorganisms to aPDT and prevent the possibility of regrowth of those that were not inactivated during the irradiation; meanwhile, aPDT is effective regardless of the resistance pattern of the strain and their use does not contribute to the selection of antimicrobial resistance. Additive or synergistic antimicrobial effects in vitro are evaluated and the best combinations are presented. The use of combined treatment of aPDT with antimicrobials could help overcome the difficulty of fighting high level of resistance microorganisms and, as it is a multi-target approach, it could make the selection of resistant microorganisms more difficult.


Sign in / Sign up

Export Citation Format

Share Document