Page 63 - CSIR-IGIB Annual Report 2020-21
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Genome based characterization of and bacteria-targeting capability of the
Propionibacterium acnes nanostructures. Targeted PTT of CHPB
For many decades, oral and topical antibiotics nanobeads shows excellent inactivation
are routinely used as primary treatment in Acne efficiency of 94.19% for Gram-negative bacteria
vulgaris with the initial goal of targeting Pseudomonas aeruginosa at 55 µg ml-1 and
Propionibacteriaceae acnes. Due to the 97.70% at 100 µg ml-1 for Gram-positive
irrational use of antibiotics, the worldwide bacteria S. aureus but great biocompatibility to
prevalence of antibiotic-resistant P. acnes is normal mammalian cells. For comparison, all
increasing, with rates varying in different parts the studies were carried out with Prussian blue
of the world. The reason for the difference in nanoparticles which showed antibacterial
the antibiotic resistance patterns of P. acnes activity at relatively higher concentrations than
among different countries is not clear, although CHPB nanobeads indicating importance of
it may be attributed to different antibiotic interfacial potential. Probing the mechanism of
prescribing habits, concomitant topical agents action revealed strong electrostatic interactions
(retinoids, benzoyl peroxide, isotretinoin, or at the cell membrane causes membrane
other antibiotics), and different P. acnes strains. depolarization and leakage of intracellular
So, it is necessary to have data on the country- contents. The photothermally assisted
specific origin of P. acnes strains and their disruption of the antioxidant defense
antimicrobial susceptibility profiles. We mechanism of the cells and increasing the
isolated 25 novel P. acnes MDR strains from oxidative stress aids bactericidal propensity of
Indian patients We further classified ten MDR the nanobeads. The superiority of targeted PTT
strains of P. acnes by MLST analysis. The Type of may be attributed to the effective crowding and
strain is very important to study the proximity of the PTT agent to the bacterial cells
pathogenesis of bacteria and also helpful in through the chitosan coating hence modulating
evaluating novel formulations for the treatment the nano-bio interface. Therefore, CHPB
of acne. In addition, we isolated six methicilin nanobeads with bacteria-targeting capability
resistant Staphylococcus aureus (MRSA) strains are promising PTT nano-devices against Gram
in this study. The novel strains of P. acnes and negative bacteria P. aeruginosa and Gram
MRSA identified in this study are very much in positive bacteria S.aureus. In future, as
demand by several industries engaged in extension of this work, our aim is to synthesize
developing skin-related formulations. a photosentisizer (fluorescein isothiocyanate-
dextran) entrapped Prussain Blue nanoparticle
Strategies to control P. acnes growth (CHPB-FD), for enhanced PDT using not only
To control the growth of bacteria, a targeted laser technology but also white light
635nm laser assisted antibacterial photoactivation. The antibacterial potency of
photothermal therapy (PTT) using chitosan- the material was studied against Gram positive
coated Prussian Blue (CHPB) nanoparticle was strains (Staphylococcus aureus), P. acne and
demonstrated. This study reveals the increase in Gram-negative strains (Pseudomonas
the therapeutic efficacy of the photothermal aeruginosa) with effective photosensitized
Prussian blue core with surface modification inactivation under white light.
using positively charged chitosan molecule
revealing the importance of interfacial potential
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