With the alarming rise in incidence of antibiotic-resistant bacteria and the scarcity of newly developed antibiotics, it is imperative that we design more effective formulations for already marketed antimicrobial agents. Fusidic acid (FA), one of the most widely used antibiotics in the topical treatment of several skin and eye infections, suffers from poor water-solubility, sub-optimal therapeutic efficacy, and a significant rise in FA-resistant Staphylococcus aureus (FRSA). In this work, the physico-chemical characteristics of FA were modified by nanocrystallization and lyophilization to improve its therapeutic efficacy through the dermal route. FA-nanocrystals (NC) were prepared using a modified nanoprecipitation technique and the influence of several formulation/process variables on the prepared FA-NC characteristics were optimized using full factorial statistical design. The optimized FA-NC formulation was evaluated before and after lyophilization by several in-vitro, ex-vivo, and microbiological tests. Furthermore, the lyophilized FA-NC formulation was incorporated into a cream product and its topical antibacterial efficacy was assessed in vivo using a rat excision wound infection model. Surface morphology of optimized FA-NC showed spherical particles with a mean particle size of 115 nm, span value of 1.6 and zeta potential of −11.6 mV. Differential scanning calorimetry and powder X-ray diffractometry confirmed the crystallinity of FA following nanocrystallization and lyophilization. In-vitro results showed a 10-fold increase in the saturation solubility of FA-NC while ex-vivo skin permeation studies showed a 2-fold increase in FA dermal deposition from FA-NC compared to coarse FA. Microbiological studies revealed a 4-fofd decrease in the MIC against S. aureus and S. epidermidis from FA-NC cream compared to commercial Fucidin cream. In-vivo results showed that FA-NC cream improved FA distribution and enhanced bacterial exposure in the infected wound, resulting in increased therapeutic efficacy when compared to coarse FA marketed as Fucidin cream.

Background: Chromobacterium violaceum (C. violaceum) is a Gram-negative bacterium mainly held to be a harmless saprophyte and only known as a biosensor strain for quorum sensing studies. However, the emergence of C. violaceum as an opportunistic pathogen is evident. In the present study, we aimed to isolate C. violaceum from soil and to test the ability of the isolates to cause infection in a murine model. Methodology: C. violaceum strain YM1 was isolated from soil using rice grains enrichment method. We identified the bacterium based on its biochemical characteristics using API 20NE as well as Vitek2. The identity of the bacterium was further confirmed on the molecular basis by phylogenetic analysis of the 16S rRNA gene sequence (GenBank accession number: MK660325). We then tested the pathogenicity of strain YM1 in a murine infection model. Results: Identification of strain YM1 revealed that it was closely related to the type strain C. violaceum ATCC 12472. Infectious doses of 104-108 cfu of YM1 were able to cause disease in mice when introduced via the intraperitoneal route. Furthermore, we provide experimental data on the antibiotic resistance phenotype of the soil isolate. Strain YM1 was resistant to multiple antibiotics to which the reference strain was susceptible. Fortunately, strain YM1 was found susceptible to fluoroquinolones; ciprofloxacin, levofloxacin, and norfloxacin. Conclusion: Here, we report on the potential clinical significance of soil isolates of C. violaceum that could be pathogenic despite their free-living style. Data presented here suggest that it is necessary to recognize C. violaceum as a suspected pathogen especially in conditions involving skin injury associated with soil.

Objectives: Microorganisms with biofilms are associated with chronic human infections (highly resistant to antimicrobial agents). Pomegranate is used in treatment of several diseases, as its peels contain phenolic compounds and hydrolysable tannins. We aimed to study the effect of PPME on inhibition of biofilms and as a natural preservative in food industrial application. Methods: Pomegranate peel was extracted with methanol. E. coli clinical isolates were identified by standard microbiological procedures. Antibiotic susceptibility testing was performed using disc diffusion method. Antibacterial activity of PPME was tested using agar well diffusion assay. Minimum Inhibitory Concentration (MIC) was evaluated according to The European Committee on Antimicrobial Susceptibility Testing (EUCAST) agar dilution method. Biofilms detection was done by Tube method. Total phenolic content (TPC) in PPME was determined using spectrophotometric method. PPME ability to scavenge (1, 1diphenyl-2-picryl hydrazyl) DPPH free radicals was assessed by the standard method. Total antioxidant capacity of PPME was evaluated by phosphormolybdenum method. Total Phenolic Content (TPC) for cooked patties was freshly analyzed at different concentrations (1-0.25mg/ml). Results: Tested isolates were multidrug resistant. High antibacterial activity of PPME was found. MIC of PPME was found to be 10mg/ml. Tested isolates were biofilms producers, PPME largely affected on biofilm forming ability. TPC for treated group was (2785.19-349.22 µg/kg): for untreated group was 1251-226 µg/kg). DPPH radical scavenging activity was 38.12-5.45%. Thiobarbituric Acid Reactive Substances (TBARS) values were measured for samples from (0 -9 days) of storage period which was 0.522-1.3,0.859-1.816mg malonladehyde/kg meat for treated, untreated group respectively. AOA% was 31.49-66.92 from (0 – 9) days of storage. Conclusions: PPME was able to inhibit biofilm formation in tested isolates and can be promising in inhibiting contamination caused by biofilm forming bacteria in food industry.

The aims of this study were to biosynthesize silver nanoparticles (AgNPs) using Bacillus subtilis supernatant, and to evaluate their in vitro antibacterial potential against human pathogens; namely Staphylococcus aureus (Staph. aureus) and Escherichia coli (E. coli). Nanoparticles (NPs) are becoming popular in different fields of research, and are useful in combating vast number of microbial diseases. NPs may be artificially synthesized in vitro using chemical methods andor via extracellular metabolites produced by the bacterial strains. In the present study, biosynthesis of AgNPs was carried out in vitro using supernatants of B. subtilis. Biosynthesized AgNPs were characterized through several physical methods. The recorded Z-average (d. nm) was 135.0 nm; with 99.2 % of the NPs displaying a hydrodynamic distance across of 188.0 nm (SD= 117.7). The polydispersity index was 0.246 and the Zeta-potential value was - 17.2 mV, which indicates good colloidal stability. Results of the Transmission electron microscope (TEM) observation indicated that the particles were spherical in shape with an average size of 21.8- 27.5 nm. The antibacterial efficacy of the AgNPs against Methicillin resistant Staph. aureus (MRSA) and E. coli clinical isolates was evaluated in vitro using the agar well diffusion. The AgNPs demonstrated antibacterial potential against MRSA and E. coli isolates; recording 18 and 15 mm diameter of zones of inhibition, respectively. The minimum inhibitory concentration (MIC) was found to be 142 µg/ ml, while the recorded minimum bactericidal concentration (MBC) was 284 µg/ ml. The mode of action of the AgNPs was investigated using the Scanning electron microscope (SEM), which was recognized as bacterial cell lysis and elongation. Current data suggest an efficient biosynthesis of stable AgNPs by B. subtilis with remarkable antibacterial potential.