RESUMO
OBJECTIVE: In this study, we evaluated the effectiveness of antimicrobial blue light (aBL; 410 nm wavelength) against ß-lactamase-carrying bacteria and the effect of aBL on the activity of ß-lactamases. METHODS: Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae strains carrying ß-lactamases as well as a purified ß-lactamase enzymes were studied. ß-lactamase activity was assessed using a chromogenic cephalosporin hydrolysis assay. Additionally, we evaluated the role of porphyrins in the photoreaction, as well as protein degradation by sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Finally, we investigated the bactericidal effect of combined aBL-ceftazidime exposure against a metallo-ß-lactamase expressing P. aeruginosa strain. RESULTS: Our study demonstrated that aBL effectively killed ß-lactamase-producing bacteria and reduced ß-lactamase activity. After an aBL exposure of 1.52 J/cm2, a 50% reduction in enzymatic activity was observed in P. aeruginosa. Additionally, we found a 40% decrease in the photoreaction activity of porphyrins following an aBL exposure of 64.8 J/cm2. We also revealed that aBL reduced ß-lactamase activity via protein degradation (after 136.4 J/cm2). Additionally, aBL markedly improved the bactericidal effect of ceftazidime (by >4-log10) in the metallo-ß-lactamase P. aeruginosa strain. CONCLUSION: Our results provide evidence that aBL compromises bacterial ß-lactamase activity, offering a potential approach to overcome ß-lactam resistance in bacteria.
Assuntos
Escherichia coli , Klebsiella pneumoniae , Pseudomonas aeruginosa , Resistência beta-Lactâmica , beta-Lactamases , beta-Lactamases/metabolismo , Pseudomonas aeruginosa/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Luz , Antibacterianos/farmacologia , Ceftazidima/farmacologia , Testes de Sensibilidade Microbiana , Luz AzulRESUMO
BACKGROUND: Cutaneous mold infections commonly result from an array of traumatic injuries that involve direct inoculation of contaminated soil into wounds. Here, we explored the use of antimicrobial blue light (aBL; 405 nm wavelength) and the combination of aBL with quinine hydrochloride (aBLâ +â Q-HCL) for the treatment of cutaneous mold infections. METHODS: Efficacy of aBL and aBLâ +â Q-HCL in killing clinically important pathogenic molds (Aspergillus fumigatus, Aspergillus flavus, and Fusarium oxyprorum) was investigated. Ultraperformance liquid chromatography identified and quantified endogenous porphyrins in the mold conidia. Finally, a mouse model of dermabrasion wound infected with a bioluminescent variant of A. fumigatus was developed to investigate the efficacy of aBL in treating cutaneous mold infections. RESULTS: We demonstrated that mold conidia are tolerant to aBL, but Q-HCL enhances efficacy. Transmission electron microscopy revealed intracellular damage by aBL. aBLâ +â Q-HCL resulted in intracellular and cell wall damage. Porphyrins were observed in all mold strains, with A. fumigatus having the highest concentration. aBL and aBLâ +â Q-HCL effectively reduced the burden of A. fumigatus within an established dermabrasion infection and limited recurrence posttreatment. CONCLUSIONS: aBL and aBLâ +â Q-HCL may offer a novel approach for the treatment of mold infections.
Assuntos
Antibacterianos/uso terapêutico , Aspergillus fumigatus/isolamento & purificação , Porfirinas , Quinina/uso terapêutico , Dermatopatias Infecciosas/tratamento farmacológico , Animais , Luz , Camundongos , Dermatopatias Infecciosas/diagnóstico , Esporos FúngicosRESUMO
BACKGROUND: The purpose of this study was to compare the efficacy of blue light therapy (BLT) and 5% topical benzoyl peroxide (BPO) gel in combination with standard chlorhexidine (CHX) preparation in eradicating Cutibacterium acnes at the deltopectoral interval measured by positive, quantitative culture findings. METHODS: Adult male volunteers were randomized to 1 of 3 treatment groups: BPO, BLT, and BPO followed by BLT. Contralateral shoulders served as matched controls. Volunteers randomized to BPO applied the gel for a total of 5 treatments. In the BLT group, a single 23-minute treatment was administered at an estimated irradiance of 40 mW/cm2 (radiant exposure, 55.2 J/cm2). In the BPO-BLT group, volunteers received both treatments as described earlier. After treatment with either BPO, BLT, or both, a single swab culture was taken from the treatment shoulder. Next, control and treatment shoulders were prepared with CHX, and cultures were taken from each shoulder. Cultures were sent for anaerobic quantitative growth analysis with both polymerase chain reaction and Sanger sequencing confirmation of presumptive C acnes colonies. RESULTS: This study enrolled 60 male volunteers, 20 per group, with no loss to follow-up. After treatment but prior to CHX administration, all culture samples in the BPO group and BLT group grew C acnes. Prior to CHX, 16 samples (80%) in the BPO-BLT group grew C acnes. On quantitative analysis, the BPO group and BPO-BLT group had significantly less growth of C acnes compared with the BLT group after treatment but prior to CHX (P < .05 for each). Following CHX administration, the BPO and BPO-BLT groups had significantly fewer positive culture findings (odds ratios of 0.03 and 0.29, respectively) and less quantity of growth compared with their control arms (P < .05). This was not seen in the BLT group. For quantitative between-group analysis, no significant synergistic effects were seen with BPO-BLT compared with BPO alone (P = .688). There was no difference in side effects between groups. CONCLUSION: The combination of topical BPO and CHX was effective at eliminating C acnes in most cases. BLT alone did not demonstrate effective antimicrobial properties against C acnes at the radiant exposure administered in this study. Combining BPO and BLT did not lead to significant synergistic antimicrobial effects. Both BPO and BLT are safe with few, transient side effects reported. More work is needed to determine whether BLT at higher radiant exposures or serial treatment results in bactericidal effects against C acnes in vivo.
Assuntos
Fármacos Dermatológicos , Articulação do Ombro , Adulto , Peróxido de Benzoíla , Clorexidina , Humanos , Masculino , Propionibacterium acnes , PeleRESUMO
BACKGROUND: Antimicrobial resistance is a significant concern to public health, and there is a pressing need to develop novel antimicrobial therapeutic modalities. METHODS: In this study, we investigated the capacity for quinine hydrochloride (Q-HCL) to enhance the antimicrobial effects of antimicrobial blue light ([aBL] 405 nm wavelength) against multidrug-resistant (MDR) Gram-negative bacteria in vitro and in vivo. RESULTS: Our findings demonstrated the significant improvement in the inactivation of MDR Pseudomonas aeruginosa and Acinetobacter baumannii (planktonic cells and biofilms) when aBL was illuminated during Q-HCL exposure. Furthermore, the addition of Q-HCL significantly potentiated the antimicrobial effects of aBL in a mouse skin abrasion infection model. In addition, combined exposure of aBL and Q-HCL did not result in any significant apoptosis when exposed to uninfected mouse skin. CONCLUSIONS: In conclusion, aBL in combination with Q-HCL may offer a novel approach for the treatment of infections caused by MDR bacteria.
Assuntos
Infecções por Acinetobacter/tratamento farmacológico , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/efeitos da radiação , Antibacterianos/uso terapêutico , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos da radiação , Quinina/uso terapêutico , Terapia Ultravioleta/métodos , Infecções por Acinetobacter/microbiologia , Acinetobacter baumannii/fisiologia , Animais , Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Biofilmes/efeitos da radiação , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/efeitos da radiação , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Plâncton/microbiologia , Pseudomonas aeruginosa/fisiologia , Quinina/farmacologia , Pele/lesões , Pele/microbiologia , Pele/patologia , Resultado do Tratamento , Ferimentos e Lesões/microbiologiaRESUMO
BACKGROUND AND OBJECTIVES: Biofilms cause more than 80% of infections in humans, including more than 90% of all chronic wound infections and are extremely resistant to antimicrobials and the immune system. The situation is exacerbated by the fast spreading of antimicrobial resistance, which has become one of the biggest threats to current public health. There is consequently a critical need for the development of alternative therapeutics. Antimicrobial blue light (aBL) is a light-based approach that exhibits intrinsic antimicrobial effect without the involvement of exogenous photosensitizers. In this study, we investigated the antimicrobial effect of this non-antibiotic approach against biofilms formed by microbial isolates of multidrug-resistant bacteria. STUDY DESIGN/MATERIALS AND METHODS: Microbial isolates of Acinetobacter baumannii, Candida albicans, Escherichia coli, Enterococcus faecalis, MRSA, Neisseria gonorrhoeae, Pseudomonas aeruginosa, and Proteus mirabilis were studied. Biofilms were grown in microtiter plates for 24 or 48 hours or in the CDC biofilm reactor for 48 hours and exposed to aBL at 405 nm (60 mW/cm2 , 60 or 30 minutes). The anti-biofilm activity of aBL was measured by viable counts. RESULTS: The biofilms of A. baumannii, N. gonorrhoeae, and P. aeruginosa were the most susceptible to aBL with between 4 and 8 log10 inactivation after 108 J/cm2 (60 mW/cm2 , 30 minutes) or 216 J/cm2 (60 mW/cm2 , 60 minutes) aBL were delivered in the microplates. On the contrary, the biofilms of C. albicans, E. coli, E. faecalis, and P. mirabilis were the least susceptible to aBL inactivation (-0.30, -0.24, -0.84, and -0.68 log10 inactivation, respectively). The same aBL treatment in biofilms developed in the CDC biofilm reactor, caused -1.68 log10 inactivation in A. baumannii and -1.74 and -1.65 log10 inactivation in two different strains of P. aeruginosa. CONCLUSIONS: aBL exhibits potential against pathogenic microorganisms and could help with the significant need for new antimicrobials in clinical practice to manage multidrug-resistant infections. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.
Assuntos
Carga Bacteriana/efeitos da radiação , Biofilmes/efeitos da radiação , Fototerapia , Acinetobacter baumannii/efeitos da radiação , Candida albicans/efeitos da radiação , Enterococcus faecalis/efeitos da radiação , Escherichia coli/efeitos da radiação , Staphylococcus aureus Resistente à Meticilina/efeitos da radiação , Neisseria gonorrhoeae/efeitos da radiação , Proteus mirabilis/efeitos da radiação , Pseudomonas aeruginosa/efeitos da radiaçãoRESUMO
BACKGROUND AND OBJECTIVE: Candida albicans is an opportunistic fungal pathogen of clinical importance and is the primary cause of fungal-associated wound infections, sepsis, or pneumonia in immunocompromised individuals. With the rise in antimicrobial resistance, it is becoming increasingly difficult to successfully treat fungal infections using traditional antifungals, signifying that alternative non-traditional approaches must be explored for their efficacy. STUDY DESIGN/MATERIALS AND METHODS: We investigated the combination of antimicrobial blue light (aBL) and quinine hydrochloride (Q-HCL) for improved inactivation of C. albicans, in vitro and in vivo, relative to either monotherapy. In addition, we evaluated the safety of this combination therapy in vivo using the TUNEL assay. RESULTS: The combination of aBL (108 J/cm2 ) with Q-HCL (1 mg/mL) resulted in a significant improvement in the inactivation of C. albicans planktonic cells in vitro, where a 7.04 log10 colony forming units (CFU) reduction was achieved, compared with aBL alone that only inactivated 3.06 log10 CFU (P < 0.001) or Q-HCL alone which did not result in a loss of viability. aBL + Q-HCL was also effective at inactivating 48-hour biofilms, with an inactivation 1.73 log10 CFU at the dose of 108 J/cm2 aBL and 1 mg/mL Q-HCL, compared with only a 0.73 or 0.66 log10 CFU by aBL and Q-HCL alone, respectively (P < 0.001). Transmission electron microscopy revealed that aBL + Q-HCL induced morphological and ultrastructural changes consistent with cell wall and cytoplasmic damage. In addition, aBL + Q-HCL was effective at eliminating C. albicans within mouse abrasion wounds, with a 2.47 log10 relative luminescence unit (RLU) reduction at the dose of 324 J/cm2 aBL and 0.4 mg/cm2 Q-HCL, compared with a 1.44 log10 RLU reduction by aBL alone. Q-HCL or nystatin alone did not significantly reduce the RLU. The TUNEL assay revealed some apoptotic cells before and 24 hours following treatment with aBL + Q-HCL. CONCLUSION: The combination of aBL + Q-HCL was effective at eliminating C. albicans both in vitro and in vivo. A comprehensive assessment of toxicity (cytotoxicity and genotoxicity) is required to fully determine the safety of aBL + Q-HCL therapy at different doses. In conclusion, the combination of aBL and Q-HCL may be a viable option for the treatment of cutaneous candidiasis. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.
Assuntos
Antimaláricos/uso terapêutico , Candida albicans/efeitos dos fármacos , Candidíase/terapia , Fototerapia , Quinina/uso terapêutico , Infecção dos Ferimentos/terapia , Animais , Biofilmes/efeitos dos fármacos , Biofilmes/efeitos da radiação , Candida albicans/efeitos da radiação , Modelos Animais de Doenças , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Infecção dos Ferimentos/etiologiaRESUMO
Antimicrobial resistance in Neisseria gonorrhoeae is a major issue of public health, and there is a critical need for the development of new antigonococcal strategies. In this study, we investigated the effectiveness of antimicrobial blue light (aBL; wavelength, 405 nm), an innovative nonpharmacological approach, for the inactivation of N. gonorrhoeae. Our findings indicated that aBL preferentially inactivated N. gonorrhoeae, including antibiotic-resistant strains, over human vaginal epithelial cells in vitro. Furthermore, no aBL-induced genotoxicity to the vaginal epithelial cells was observed at the radiant exposure used to inactivate N. gonorrhoeae. aBL also effectively inactivated N. gonorrhoeae that had attached to and invaded into the vaginal epithelial cells in their cocultures. No gonococcal resistance to aBL developed after 15 successive cycles of inactivation induced by subtherapeutic exposure to aBL. Endogenous aBL-activatable photosensitizing porphyrins in N. gonorrhoeae were identified and quantified using ultraperformance liquid chromatography, with coproporphyrin being the most abundant species in all N. gonorrhoeae strains studied. Singlet oxygen was involved in aBL inactivation of N. gonorrhoeae. Together, these findings show that aBL represents a potential potent treatment for antibiotic-resistant gonococcal infection.
Assuntos
Gonorreia/radioterapia , Neisseria gonorrhoeae/efeitos da radiação , Abetalipoproteinemia , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos da radiação , Células Epiteliais/microbiologia , Feminino , Gonorreia/tratamento farmacológico , Humanos , Luz , Testes de Sensibilidade Microbiana , Neisseria gonorrhoeae/efeitos dos fármacos , Neisseria gonorrhoeae/crescimento & desenvolvimento , Oxigênio , Azida Sódica , Vagina/microbiologiaRESUMO
Blue light (BL) exerts an antimicrobial effect on pathogenic bacteria. It has been hypothesized that its bactericidal activity depends upon the generation of reactive oxygen species (such as anion superoxides) and the resultant cellular damage. However, some aspects of this hypothesis needed to be tested and investigated. Thus, the work conducted herein examined the molecular impact of BL treatment on Cronobacter sakazakii, an emerging foodborne pathogen. The results showed that BL exhibited an efficient bactericidal effect against C. sakazakii. Under a sublethal BL dose, both intracellular anion superoxides and malondialdehyde (a marker of oxidative stress) contents were increased gradually. Moreover, permeability of the outer membrane was increased by approximately 50%, indicating membrane damage. Further investigation revealed alterations to cellular fatty acid profiles, with a decrease and disappearance of unsaturated fatty acids, including C18:2, C16:1, and C18:1. These data indicate that bacterial lipids, especially unsaturated fatty acids, are important molecular targets of BL photo-oxidation. The transcriptional response of bacteria to BL was also studied, and it was found that three genes were upregulated, including genes encoding antioxidants. The current study contributes towards an improved understanding of the bactericidal mechanisms of BL and highlights the importance of lipid and membrane damage.
Assuntos
Cronobacter sakazakii/efeitos da radiação , Ácidos Graxos/efeitos da radiação , Luz , Estresse Oxidativo/efeitos da radiação , Membrana Externa Bacteriana/metabolismo , Membrana Externa Bacteriana/efeitos da radiação , Cronobacter sakazakii/genética , Cronobacter sakazakii/metabolismo , Ácidos Graxos/química , Genes Bacterianos/genética , Viabilidade Microbiana/efeitos da radiação , Espécies Reativas de Oxigênio/metabolismo , Regulação para Cima/efeitos da radiaçãoRESUMO
BACKGROUND AND OBJECTIVES: The aim of this study was to investigate the efficacy, safety, and mechanism of action of antimicrobial blue light (aBL) for the inactivation of Neisseria gonorrhoeae, the etiological agent of gonorrhea. STUDY DESIGN/MATERIALS AND METHODS: The susceptibilities of N. gonorrhoeae (ATCC 700825) in planktonic suspensions to aBL at 405- and 470-nm wavelengths were compared. The roles of oxygen in the anti-gonococcal activity of aBL were studied by examining the effects of hypoxic condition (blowing N2 ) on the anti-gonococcal efficiency of 405-nm aBL. The presence, identification, and quantification of endogenous photosensitizers in N. gonorrhoeae cells and human vaginal epithelial cells (VK2/E6E7 cells) were determined using fluorescence spectroscopy and ultra-performance liquid chromatography (UPLC). Finally, the selectivity of aBL inactivation of N. gonorrhoeae over the host cells were investigated by irradiating the co-cultures of N. gonorrhoeae and human vaginal epithelial cells using 405-nm aBL. RESULTS: About 3.12-log10 reduction of bacterial colony forming units (CFU) was achieved by 27 J/cm 2 exposure at 405 nm, while about 3.70-log10 reduction of bacterial CFU was achieved by 234 J/cm2 exposure at 470 nm. The anti-gonococcal efficacy of 405-nm aBL was significantly suppressed under hypoxic condition. Spectroscopic and UPLC analyses revealed the presence of endogenous porphyrins and flavins in N. gonorrhoeae. The concentrations of endogenous photosensitizers in N. gonorrhoeae (ATCC 700825) cells were more than 10 times higher than those in the VK2/E6E7 cells. In the co-cultures of N. gonorrhoeae and VK2/E6E7 cells, 405-nm aBL at 108 J/cm2 preferentially inactivated N. gonorrhoeae cells while sparing the vaginal epithelial cells. CONCLUSIONS: aBL at 405-nm wavelength is more effective than 470-nm wavelength in inactivating N. gonorrhoeae while sparing the vaginal epithelial cells. Reactive oxygen species generated from the photochemical reactions between aBL and endogenous photosensitizers play a vital role in the anti-gonococcal activity of 405-nm aBL. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.
Assuntos
Luz , Neisseria gonorrhoeae/metabolismo , Neisseria gonorrhoeae/efeitos da radiação , Oxigênio/metabolismo , Espécies Reativas de Oxigênio , Contagem de Colônia Microbiana , Humanos , Fenômenos FísicosRESUMO
As an innovative non-antibiotic approach, antimicrobial blue light in the spectrum of 400-470nm has demonstrated its intrinsic antimicrobial properties resulting from the presence of endogenous photosensitizing chromophores in pathogenic microbes and, subsequently, its promise as a counteracter of antibiotic resistance. Since we published our last review of antimicrobial blue light in 2012, there have been a substantial number of new studies reported in this area. Here we provide an updated overview of the findings from the new studies over the past 5 years, including the efficacy of antimicrobial blue light inactivation of different microbes, its mechanism of action, synergism of antimicrobial blue light with other angents, its effect on host cells and tissues, the potential development of resistance to antimicrobial blue light by microbes, and a novel interstitial delivery approach of antimicrobial blue light. The potential new applications of antimicrobial blue light are also discussed.
Assuntos
Bactérias/efeitos da radiação , Infecções Bacterianas/terapia , Fungos/efeitos da radiação , Micoses/terapia , Fototerapia/métodos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bactérias/efeitos dos fármacos , Bactérias/patogenicidade , Infecções Bacterianas/microbiologia , Farmacorresistência Bacteriana , Fungos/efeitos dos fármacos , Fungos/patogenicidade , Humanos , Luz , Testes de Sensibilidade Microbiana , Micoses/microbiologia , Resultado do TratamentoRESUMO
BACKGROUND: Biofilms affect >80% bacterial infections in human and are usually difficult to eradicate because of their inherent drug resistance. METHODS: We investigated the effectiveness of antimicrobial blue light (aBL) (wavelength, 415 nm) for inactivating Acinetobacter baumannii or Pseudomonas aeruginosa biofilms in 96-well microplates or infected mouse burn wounds. RESULTS: In vitro, in 96-well microplates, exposure of 24-hour-old and 72-hour-old A. baumannii biofilms to 432 J/cm(2) aBL resulted in inactivation of 3.59 log10 and 3.18 log10 colony-forming units (CFU), respectively. For P. aeruginosa biofilms, similar levels of inactivation-3.02 log10 and 3.12 log10 CFU, respectively-were achieved. In mouse burn wounds infected with 5 × 10(6) CFU ofA. baumannii, approximately 360 J/cm(2) and 540 J/cm(2) aBL was required to inactivate 3 log10 CFU in biofilms when delivered 24 and 48 hours, respectively, after bacterial inoculation. High-performance liquid chromatography analysis revealed the presence of endogenous porphyrins in both A. baumannii and P. aeruginosa TUNEL assay detected no apoptotic cells in aBL-irradiated mouse skin at up to 24 hours after aBL exposure (540 J/cm(2)). CONCLUSIONS: aBL has antimicrobial activity in biofilms ofA. baumannii and P. aeruginosa and is a potential therapeutic approach for biofilm-related infections.
Assuntos
Acinetobacter baumannii/efeitos da radiação , Biofilmes/efeitos da radiação , Desinfecção/métodos , Infecções por Bactérias Gram-Negativas/microbiologia , Pseudomonas aeruginosa/efeitos da radiação , Animais , Apoptose/efeitos da radiação , Queimaduras/microbiologia , Modelos Animais de Doenças , Feminino , Luz , Modelos Lineares , Camundongos , Camundongos Endogâmicos BALB C , Imagem Óptica , Infecção dos Ferimentos/microbiologiaRESUMO
Pseudomonas aeruginosa is among the most common pathogens that cause nosocomial infections and is responsible for about 10% of all hospital-acquired infections. In the present study, we investigated the potential development of tolerance of P. aeruginosa to antimicrobial blue light by carrying 10 successive cycles of sublethal blue light inactivation. The high-performance liquid chromatographic (HPLC) analysis was performed to identify endogenous porphyrins in P. aeruginosa cells. In addition, we tested the effectiveness of antimicrobial blue light in a mouse model of nonlethal skin abrasion infection by using a bioluminescent strain of P. aeruginosa. The results demonstrated that no tolerance was developed to antimicrobial blue light in P. aeruginosa after 10 cycles of sub-lethal inactivation. HPLC analysis showed that P. aeruginosa is capable of producing endogenous porphyrins in particularly, coproporphyrin III, which are assumed to be responsible for the photodynamic effects of blue light alone. P. aeruginosa infection was eradicated by antimicrobial blue light alone (48 J/cm(2) ) without any added photosensitizer molecules in the mouse model. In conclusion, endogenous photosensitization using blue light should gain considerable attention as an effective and safe alternative antimicrobial therapy for skin infections. Lasers Surg. Med. 48:562-568, 2016. © 2016 Wiley Periodicals, Inc.
Assuntos
Desinfecção/métodos , Luz , Fototerapia/métodos , Porfirinas/metabolismo , Infecções por Pseudomonas/terapia , Pseudomonas aeruginosa/efeitos da radiação , Dermatopatias Bacterianas/terapia , Animais , Biomarcadores/metabolismo , Cromatografia Líquida de Alta Pressão , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Pseudomonas aeruginosa/metabolismoRESUMO
In this study, we investigated the utility of antimicrobial blue light therapy for multidrug-resistant Acinetobacter baumannii infection in a mouse burn model. A bioluminescent clinical isolate of multidrug-resistant A. baumannii was obtained. The susceptibility of A. baumannii to blue light (415 nm)-inactivation was compared in vitro to that of human keratinocytes. Repeated cycles of sublethal inactivation of bacterial by blue light were performed to investigate the potential resistance development of A. baumannii to blue light. A mouse model of third degree burn infected with A. baumannii was developed. A single exposure of blue light was initiated 30 minutes after bacterial inoculation to inactivate A. baumannii in mouse burns. It was found that the multidrug-resistant A. baumannii strain was significantly more susceptible than keratinocytes to blue light inactivation. Transmission electron microscopy revealed blue light-induced ultrastructural damage in A. baumannii cells. Fluorescence spectroscopy suggested that endogenous porphyrins exist in A. baumannii cells. Blue light at an exposure of 55.8 J/cm(2) significantly reduced the bacterial burden in mouse burns. No resistance development to blue light inactivation was observed in A. baumannii after 10 cycles of sublethal inactivation of bacteria. No significant DNA damage was detected in mouse skin by means of a skin TUNEL assay after a blue light exposure of 195 J/cm(2).
Assuntos
Acinetobacter baumannii/efeitos da radiação , Queimaduras/terapia , Farmacorresistência Bacteriana Múltipla , Fototerapia , Infecção dos Ferimentos/microbiologia , Infecção dos Ferimentos/terapia , Infecções por Acinetobacter/terapia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/ultraestrutura , Animais , Anti-Infecciosos/uso terapêutico , Queimaduras/microbiologia , Dano ao DNA/efeitos da radiação , Modelos Animais de Doenças , Feminino , Queratinócitos , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de TransmissãoRESUMO
Low-level laser (light) therapy (LLLT) promotes wound healing, reduces pain and inflammation, and prevents tissue death. Studies have explored the effects of various radiant exposures on the effect of LLLT; however, studies of wavelength dependency in in vivo models are less common. In the present study, the healing effects of LLLT mediated by different wavelengths of light in the red and near-infrared (NIR) wavelength regions (635, 730, 810, and 980 nm) delivered at constant fluence (4 J/cm(2)) and fluence rate (10 mW/cm(2)) were evaluated in a mouse model of partial-thickness dermal abrasion. Wavelengths of 635 and 810 nm were found to be effective in promoting the healing of dermal abrasions. However, treatment using 730- and 980-nm wavelengths showed no sign of stimulated healing. Healing was maximally augmented in mice treated with an 810-nm wavelength, as evidenced by significant wound area reduction (p < 0.05), enhanced collagen accumulation, and complete re-epithelialization as compared to other wavelengths and non-illuminated controls. Significant acceleration of re-epithelialization and cellular proliferation revealed by immunofluorescence staining for cytokeratin-14 and proliferating cell nuclear antigen (p < 0.05) was evident in the 810-nm wavelength compared with other groups. Photobiomodulation mediated by red (635 nm) and NIR (810 nm) light suggests that the biological response of the wound tissue depends on the wavelength employed. The effectiveness of 810-nm wavelength agrees with previous publications and, together with the partial effectiveness of 635 nm and the ineffectiveness of 730 and 980 nm wavelengths, can be explained by the absorption spectrum of cytochrome c oxidase, the candidate mitochondrial chromophore in LLLT.
Assuntos
Terapia com Luz de Baixa Intensidade/métodos , Pele/lesões , Pele/efeitos da radiação , Cicatrização/efeitos da radiação , Animais , Proliferação de Células/efeitos da radiação , Modelos Animais de Doenças , Imuno-Histoquímica , Raios Infravermelhos/uso terapêutico , Queratina-14/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fenômenos Ópticos , Antígeno Nuclear de Célula em Proliferação/metabolismo , Reepitelização/efeitos da radiação , Pele/metabolismo , Cicatrização/fisiologiaRESUMO
Antimicrobial strategies for musculoskeletal infections are typically first developed with in vitro models. The In Vitro Section of the 2023 Orthopedic Research Society Musculoskeletal Infection international consensus meeting (ICM) probed our state of knowledge of in vitro systems with respect to bacteria and biofilm phenotype, standards, in vitro activity, and the ability to predict in vivo efficacy. A subset of ICM delegates performed systematic reviews on 15 questions and made recommendations and assessment of the level of evidence that were then voted on by 72 ICM delegates. Here, we report recommendations and rationale from the reviews and the results of the internet vote. Only two questions received a ≥90% consensus vote, emphasizing the disparate approaches and lack of established consensus for in vitro modeling and interpretation of results. Comments on knowledge gaps and the need for further research on these critical MSKI questions are included.
Assuntos
Biofilmes , ConsensoRESUMO
Blue light has attracted increasing attention due to its intrinsic antimicrobial effect without the addition of exogenous photosensitizers. However, the use of blue light for wound infections has not been established yet. In this study, we demonstrated the efficacy of blue light at 415 nm for the treatment of acute, potentially lethal Pseudomonas aeruginosa burn infections in mice. Our in vitro studies demonstrated that the inactivation rate of P. aeruginosa cells by blue light was approximately 35-fold higher than that of keratinocytes (P = 0.0014). Transmission electron microscopy revealed blue light-mediated intracellular damage to P. aeruginosa cells. Fluorescence spectroscopy suggested that coproporphyrin III and/or uroporphyrin III are possibly the intracellular photosensitive chromophores associated with the blue light inactivation of P. aeruginosa. In vivo studies using an in vivo bioluminescence imaging technique and an area-under-the-bioluminescence-time-curve (AUBC) analysis showed that a single exposure of blue light at 55.8 J/cm(2), applied 30 min after bacterial inoculation to the infected mouse burns, reduced the AUBC by approximately 100-fold in comparison with untreated and infected mouse burns (P < 0.0001). Histological analyses and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assays indicated no significant damage in the mouse skin exposed to blue light at the effective antimicrobial dose. Survival analyses revealed that blue light increased the survival rate of the infected mice from 18.2% to 100% (P < 0.0001). In conclusion, blue light therapy might offer an effective and safe alternative to conventional antimicrobial therapy for P. aeruginosa burn infections.
Assuntos
Queimaduras/terapia , Infecções por Pseudomonas/terapia , Pseudomonas aeruginosa/efeitos da radiação , Infecção dos Ferimentos/terapia , Animais , Queimaduras/microbiologia , Queimaduras/patologia , Sobrevivência Celular/efeitos da radiação , Feminino , Marcação In Situ das Extremidades Cortadas , Queratinócitos/citologia , Queratinócitos/efeitos da radiação , Luz , Camundongos , Camundongos Endogâmicos BALB C , Viabilidade Microbiana/efeitos da radiação , Fototerapia , Infecções por Pseudomonas/microbiologia , Infecções por Pseudomonas/patologia , Pseudomonas aeruginosa/crescimento & desenvolvimento , Infecção dos Ferimentos/microbiologia , Infecção dos Ferimentos/patologiaRESUMO
Blue light, particularly in the wavelength range of 405-470 nm, has attracted increasing attention due to its intrinsic antimicrobial effect without the addition of exogenous photosensitizers. In addition, it is commonly accepted that blue light is much less detrimental to mammalian cells than ultraviolet irradiation, which is another light-based antimicrobial approach being investigated. In this review, we discussed the blue light sensing systems in microbial cells, antimicrobial efficacy of blue light, the mechanism of antimicrobial effect of blue light, the effects of blue light on mammalian cells, and the effects of blue light on wound healing. It has been reported that blue light can regulate multi-cellular behavior involving cell-to-cell communication via blue light receptors in bacteria, and inhibit biofilm formation and subsequently potentiate light inactivation. At higher radiant exposures, blue light exhibits a broad-spectrum antimicrobial effect against both Gram-positive and Gram-negative bacteria. Blue light therapy is a clinically accepted approach for Propionibacterium acnes infections. Clinical trials have also been conducted to investigate the use of blue light for Helicobacter pylori stomach infections and have shown promising results. Studies on blue light inactivation of important wound pathogenic bacteria, including Staphylococcus aureus and Pseudomonas aeruginosa have also been reported. The mechanism of blue light inactivation of P. acnes, H. pylori, and some oral bacteria is proved to be the photo-excitation of intracellular porphyrins and the subsequent production of cytotoxic reactive oxygen species. Although it may be the case that the mechanism of blue light inactivation of wound pathogens (e.g., S. aureus, P. aeruginosa) is the same as that of P. acnes, this hypothesis has not been rigorously tested. Limited and discordant results have been reported regarding the effects of blue light on mammalian cells and wound healing. Under certain wavelengths and radiant exposures, blue light may cause cell dysfunction by the photo-excitation of blue light sensitizing chromophores, including flavins and cytochromes, within mitochondria or/and peroxisomes. Further studies should be performed to optimize the optical parameters (e.g., wavelength, radiant exposure) to ensure effective and safe blue light therapies for infectious disease. In addition, studies are also needed to verify the lack of development of microbial resistance to blue light.
Assuntos
Acne Vulgar/terapia , Infecções por Bactérias Gram-Positivas/terapia , Infecções por Helicobacter/terapia , Helicobacter pylori/efeitos da radiação , Fototerapia/métodos , Propionibacterium acnes/efeitos da radiação , Animais , Infecções por Bactérias Gram-Positivas/microbiologia , Infecções por Helicobacter/microbiologia , Humanos , Luz , Cicatrização/efeitos da radiaçãoRESUMO
Fullerenes are promising candidates for photodynamic therapy (PDT). Thus, C70 and novel C84O2 fullerenes were functionalized with and without an additional deca-tertiary ethyleneamino-chain as an electron source, giving rise to two distinct pairs of photosensitizers, the monoadducts LC-17, LC-19 and the bisadducts LC18 and LC-20 to perform PDT in HeLa cells with UVA, blue, green, white and red light. Shorter wavelengths gave more phototoxicity with LC-20 while LC-19 was better at longer wavelengths; the ratio between killing obtained with LC-19 and LC-20 showed an almost perfect linear correlation (R = 0.975) with wavelength. The incorporation of a deca-tertiary amine chain in the C84O2 fullerene gave more PDT killing when excited with shorter wavelengths or in the presence of low ascorbate concentration through higher generation of hydroxyl radicals. Photoactivated C84O2 fullerenes induced apoptosis of HeLa cancer cells, together with mitochondrial and lysosomal damage demonstrated by acridine orange and rhodamine 123 fluorescent probes. FROM THE CLINICAL EDITOR: Photoactivated C70 and C84O2 fullerenes were demonstrated to induce apoptosis of HeLa cancer cells, together with mitochondrial and lysosomal damage, as a function of wavelength. The study is paving the way to future clinical uses of these agents in photodynamic therapy.
Assuntos
Fulerenos/química , Fotoquimioterapia , Transporte de Elétrons , Radicais Livres , Células HeLa , Humanos , Processos Fotoquímicos , Solubilidade , Água/químicaRESUMO
A metagenome contains all DNA sequences from an environmental sample, including viruses, bacteria, archaea, and eukaryotes. Since viruses are of huge abundance and have caused vast mortality and morbidity to human society in history as a type of major pathogens, detecting viruses from metagenomes plays a crucial role in analyzing the viral component of samples and is the very first step for clinical diagnosis. However, detecting viral fragments directly from the metagenomes is still a tough issue because of the existence of a huge number of short sequences. In this study a hybrid Deep lEarning model for idenTifying vIral sequences fRom mEtagenomes (DETIRE) is proposed to solve the problem. First, the graph-based nucleotide sequence embedding strategy is utilized to enrich the expression of DNA sequences by training an embedding matrix. Then, the spatial and sequential features are extracted by trained CNN and BiLSTM networks, respectively, to enrich the features of short sequences. Finally, the two sets of features are weighted combined for the final decision. Trained by 220,000 sequences of 500 bp subsampled from the Virus and Host RefSeq genomes, DETIRE identifies more short viral sequences (<1,000 bp) than the three latest methods, such as DeepVirFinder, PPR-Meta, and CHEER. DETIRE is freely available at Github (https://github.com/crazyinter/DETIRE).
RESUMO
In recent years, with the increases in microorganisms that express a multitude of antimicrobial resistance (AMR) mechanisms, the threat of antimicrobial resistance in the global population has reached critical levels. The introduction of the COVID-19 pandemic has further contributed to the influx of infections caused by multidrug-resistant organisms (MDROs), which has placed significant pressure on healthcare systems. For over a century, the potential for light-based approaches targeted at combatting both cancer and infectious diseases has been proposed. They offer effective killing of microbial pathogens, regardless of AMR status, and have not typically been associated with high propensities of resistance development. To that end, the goal of this review is to describe the different mechanisms that drive AMR, including intrinsic, phenotypic, and acquired resistance mechanisms. Additionally, the different light-based approaches, including antimicrobial photodynamic therapy (aPDT), antimicrobial blue light (aBL), and ultraviolet (UV) light, will be discussed as potential alternatives or adjunct therapies with conventional antimicrobials. Lastly, we will evaluate the feasibility and requirements associated with integration of light-based approaches into the clinical pipeline.