The effect of antimicrobial photodynamic therapy against virulence genes expression in colistin-resistance <i>Acinetobacter baumannii</i>

Abstract

Background and Aims: The emergence of drug-resistant infections is a global problem. Acinetobacter baumannii has attracted much attention over the last few years because of resistance to a wide range of antibiotics. Applying new non-antibiotic methods can save lives of many people around the world. Antimicrobial photodynamic therapy (aPDT) technique can be used as a new method for controlling the infections. In this study we investigated the effect of aPDT on the expression of pathogenic genes in colistin-resistance A. baumannii isolated from a burn patient. Materials and methods: The suspension of colistin-resistance A. baumannii was incubated with 0.01 mg/ml of toluidine blue O (TBO) in the dark; then the light emitting diode device with a wavelength of 630 ± 10 nm and output intensity of 2000-4000 mW /cm 2 was irradiated to the suspension at room temperature. Subsequently, after the aPDT, genes expression of ompA and pilZ was investigated by using real-time polymerase chain reaction technique. Results: Among the genes studied, the transcript of the ompA gene after aPDT was increased significantly in comparison with control groups (P < 0.05). Whereas, there was no remarkable different in pilZ gene expression (P > 0.05). Conclusions: It can be concluded from the results that the ompA as an outer membrane of A. baumannii is degraded after exposing aPDT and it will probably be done the penetration of antibiotics into cells of this bacterium easily.

Clinical analysis of colistin sulfate in the treatment of pneumonia caused by carbapenem-resistant Gram-negative bacteria

“…Previous studies have shown that the clearance rate of K. pneumoniae infection when treated with intravenous and nebulized polymyxin sulfate is higher than that with polymyxin sulfate alone. The combined use of intravenous injection and nebulization can also reduce the average intubation time and amount of polymyxin sulfate used during ICU hospitalization[ 33 ]. The main side effects of polymyxin include nephrotoxicity and neurotoxicity[ 34 ].…”

Antimicrobial Photodynamic Therapy: Latest Developments with a Focus on Combinatory Strategies

“…Again, microorganisms can induce the overproduction of proteins involved in the repair of photodamaged DNA; however, some bacteria, such as Helicobacter pylori, possess only a few of such protective repair mechanisms [31]. Upon PDT treatment, ROS and 1 O 2 can modify bacterial gene expression profiles by modulating (i) the quorum sensing pathway, therefore inhibiting biofilm formation as shown in in vitro models, and/or (ii) the anti-virulence activities by reducing the gene expression of virulence factors in diverse clinical pathogens [32][33][34][35].…”

Factors mediating Acinetobacter baumannii biofilm formation: Opportunities for developing therapeutics

“…Photodynamic therapy alone has been demonstrated to be ineffective in complete eradication of the pathogen, but synergistic effects along with antimicrobials such as gentamycin, imipenem, and colistin resulted in increased killing of PDR and XDR A. baumannii ( De Mello et al., 2019 ; Pourhajibagher et al., 2017 ; Wozniak et al., 2019 ). A study showed that A. baumannii , when treated with sublethal antimicrobial photodynamic therapy (aPDT) resulted in significantly increased expression of ompA, probably to compensate for its damage and enable bacterial survival ( Boluki et al., 2019 ). Besides antimicrobials, natural compounds such as chitosan have been studied in combination with PDT to effectively eradicate biofilm-associated A. baumannii cells ( Zhang et al., 2019 ; Fekrirad et al., 2021 ).…”