Synthesis and characterization of marine seagrass (Cymodocea serrulata) mediated titanium dioxide nanoparticles for antibacterial, antibiofilm and antioxidant properties.

Cymodocea serrulata mediated titanium dioxide nanoparticles (TiO2 NPs) were successfully synthesized. The XRD pattern and FTIR spectra demonstrated the crystalline structure of TiO2 NPs and the presence of phenols, flavonoids and alkaloids in the extract. Further SEM revealed that TiO2 NPs has uniform structure and spherical in shape with their size ranged from 58 to 117 nm. Antibacterial activity of TiO2 NPs against methicillin-resistant Staphylococcus aureus (MRSA) and Vibrio cholerae (V. cholerae), provided the zone of inhibition of 33.9 ± 1.7 and 36.3 ± 1.9 mm, respectively at 100 µg/mL concentration. MIC of TiO2 NPs against MRSA and V. cholerae showed 84% and 87% inhibition at 180 µg/mL and 160 µg/mL respectively. Subsequently, the sub-MIC of V. cholerae demonstrated minimal or no impact on bacterial growth at concentration of 42.5 µg/mL concentration. In addition, TiO2 NPs exhibited their ability to inhibit the biofilm forming V. cholerae which caused distinct morphological and intercellular damages analysed using CLSM and TEM. The antioxidant properties of TiO2 NPs were demonstrated through TAA and DPPH assays and exposed its scavenging activity with IC50 value of 36.42 and 68.85 µg/mL which denotes its valuable antioxidant properties with potential health benefits. Importantly, the brine shrimp based lethality experiment yielded a low cytotoxic effect with 13% mortality at 100 µg/mL. In conclusion, the multifaceted attributes of C. serrulata mediated TiO2 NPs encompassed the antibacterial, antioxidant and anti-biofilm inhibition effects with low cytotoxicity in nature were highlighted in this study and proved the bioderived TiO2 NPs could be used as a promising agent for biomedical applications.

Anti-quorum Sensing and Anti-biofilm Effect of Nocardiopsis synnemataformans RMN 4 (MN061002) Compound 2,6-Di-tert-butyl, 1,4-Benzoquinone Against Biofilm-Producing Bacteria.

In this study, the anti-biofilm compound of 2,6-Di-tert-butyl, 1,4-benzoquinone was purified from Nocardiopsis synnemataformans (N. synnemataformans) RMN 4 (MN061002). To confirm the compound, various spectroscopy analyses were done including ultraviolet (UV) spectrometer, Fourier transform infrared spectroscopy (FTIR), analytical high-performance liquid chromatography (HPLC), preparative HPLC, gas chromatography-mass spectroscopy (GC-MS), liquid chromatography-mass spectroscopy (LC-MS), and 2D nuclear magnetic resonance (NMR). Furthermore, the purified compound was shown 94% inhibition against biofilm-producing Proteus mirabilis (P. mirabilis) (MN396686) at 70 µg/mL concentrations. Furthermore, the metabolic activity, exopolysaccharide damage, and hydrophobicity degradation results of identified compound exhibited excellent inhibition at 100 µg/mL concentration. Furthermore, the confocal laser scanning electron microscope (CLSM) and scanning electron microscope (SEM) results were shown with intracellular damages and architectural changes in bacteria. Consecutively, the in vivo toxicity effect of the compound against Artemia franciscana (A. franciscana) was shown to have a low mortality rate at 100 µg/mL. Finally, the molecular docking interaction between the quorum sensing (QS) genes and identified compound clearly suggested that the identified compound 2,6-Di-tert-butyl, 1,4-benzoquinone has anti-quorum sensing and anti-biofilm activities against P. mirabilis (MN396686).

Partially purified actinomycetes compounds enhance the intracellular damages in multi-drug resistant P. aeruginosa and K. pneumoniae.

Based on the excellent nutrient level, the current study was focused on isolation and anti-bacterial activity of the actinomycetes from marine mangrove soil samples. As result, 10 different strains of actinomycetes strains were identified on actinomycetes isolation agar plates. The identified strains were shown with white, clear, uncontaminated well matured spore producing ability. Based on the initial observation, the isolated colonies were actinomycetes. The partially extracted crude compound shown excellent anti-bacterial activity against P. aeruginosa and K. pneumoniae with 15 mm and 13 mm zone of inhibitions were observed at 500 µL concentrations. The minimum inhibition concentration result was also confirmed the 500 µL concentration against both the tested concentration with high inhibition rate. Then, the intracellular damages, decreased cell growth of the crude actinomycetes extract treated bacterial strains were clearly observed by confocal laser scanning electron microscope. The extracellular damages of bacterial cell wall and shape of the both the pathogens were clearly shown by scanning electron microscope. Therefore, all the results were clearly supported to the partially extracted crude compound and it has excellent anti-bacterial activity against tested multi drug resistant bacteria.

Piperacillin/tazobactum and cefotaxime decrease the effect of beta lactamase production in multi-drug resistant K. pneumoniae.

BACKGROUND: Worldwide, multi-drug resistant Klebsiella pneumoniae (K. pneumonia) and their virulence's were contributed more in the multi-drug resistant effect. According to the World Health organization report, it is an emerging thread in developing countries and also comes under first ever critical list. In this context, the current study was concentrated on detection of extended spectrum beta lactamase (ESBL) producing strain and their antimicrobial susceptibility study of K. pneumoniae. MATERIALS AND METHODS: Firstly, the multi-drug resistant effect of the K. pneumoniae was identified from specific CLSI guidelines recommended antibiotics by disc diffusion method. Consecutively, the primary ESBL identification test was performed using ceftazidime and cefotaxime, followed by double disc combination and phenotypic confirmation tests using ceftazidime/clavulanic acid and cefotaxime/clavulanic acid. Finally, the minimum inhibition concentration of some important sensitive antibiotics were performed against selected K. pneumoniae was confirmed by micro broth dilution method. RESULTS AND CONCLUSIONS: The current result was most favorable to selected K. pneumoniae with more multi drug resistant characteristic nature. All the performed antibiotics were almost more sensitive to selected K. pneumoniae. The effective antibiotics of piperacillin was also exhibited more resistant effect against tested bacteria and it cleaved the bacterial enzyme clearly. The present result of primary ESBL identification test result was exhibited with ≤22 mm and ≤27 mm against ceftazidime and cefotaxime were observed respectively. Followed result of double disc combination and phenotypic confirmation experiments results were clearly stated that the selected K. pneumoniae was ESBL producer. The ceftazidime, cefotaxime and ceftazidime/clavulanic acid and cefotaxime/clavulanic acid were exhibited with merged zones and ≥5 mm zones around the combination disc when compared with disc alone were observed. All the ESBL detection test results were clearly indicated that the selected K. pneumoniae strain was ESBL producer.