In vitro photoinactivation effectiveness of a portable LED device aimed for intranasal photodisinfection and a photosensitizer formulation comprising methylene blue and potassium iodide against bacterial, fungal, and viral respiratory pathogens

• Published in: Lasers in medical science 2024-02, Vol.39 (1), p.60-60, Article 60
• Main Authors: Chakraborty, Sourabrata, Mohanty, Deepanwita, Chowdhury, Anupam, Krishna, Hemant, Taraphdar, Debjani, Chitnis, Sheetal, Sodani, Sadhna, Sahu, Khageswar, Majumder, Shovan Kumar
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents; Antibiotic resistance; Antibiotics; Bacteria; COVID-19; Dentistry; Drug resistance; Effectiveness; Fluence; Fungi; Iodides; Klebsiella; Lasers; Medicine; Medicine & Public Health; Methicillin; Methicillin-Resistant Staphylococcus aureus; Methylene blue; Methylene Blue - pharmacology; Microorganisms; Nose; Optical Devices; Optics; Original Article; Pathogens; Photodynamic therapy; Photoinactivation; Photonics; Photosensitizing Agents - pharmacology; Portable equipment; Potassium; Potassium iodide; Potassium Iodide - pharmacology; Potassium iodides; Quantum Optics; Respiratory diseases; SARS-CoV-2; Severe acute respiratory syndrome coronavirus 2; Staphylococcus infections; Viral diseases
• ISSN: 1435-604X; 0268-8921; 1435-604X
• DOI: 10.1007/s10103-024-03996-2

Antimicrobial photodynamic therapy (aPDT) can be a viable option for management of intranasal infections. However, there are light delivery, fluence, and photosensitizer-related challenges. We report in vitro effectiveness of an easily fabricated, low-cost, portable, LED device and a formulation comprising methylene blue (MB) and potassium iodide (KI) for photoinactivation of pathogens of the nasal cavity, namely, methicillin-resistant Staphylococcus aureus , antibiotic-resistant Klebsiella pneumoniae , multi-antibiotic-resistant Pseudomonas aeruginosa , Candida spp., and SARS-CoV-2. In a 96-well plate, microbial suspensions incubated with 0.005% MB alone or MB and KI formulation were exposed to different red light (~ 660 ± 25 nm) fluence using the LED device fitted to each well. Survival loss in bacteria and fungi was quantified using colony-forming unit assay, and SARS-CoV-2 photodamage was assessed by RT-PCR. The results suggest that KI addition to MB leads to KI concentration-dependent potentiation (up to ~ 5 log 10 ) of photoinactivation in bacteria and fungi. aPDT in the presence of 25 or 50 mM KI shows the following photoinactivation trend; Gm + ve bacteria  > Gm − ve bacteria > fungi  > virus. aPDT in the presence of 100 mM KI, using 3- or 5-min red light exposure, results in complete eradication of bacteria or fungi, respectively. For SARS-CoV-2, aPDT using MB-KI leads to a ~ 6.5 increase in cycle threshold value. The results demonstrate the photoinactivation effectiveness of the device and MB-KI formulation, which may be helpful in designing of an optimized protocol for future intranasal photoinactivation studies in clinical settings.