Antibacterial activity and safety of commercial veterinary cationic steroid antibiotics and neutral superoxidized water

<div><p>Antibiotic resistance of bacteria common to the ocular surface is an evolving problem. Thus, novel treatment options with new modes of action are required. We investigated the antibacterial activity and safety of three commercially available topical veterinary ophthalmic products (cationic steroid antibiotics, products A and B, and a neutral superoxidized water, product C) to determine their potential use as antimicrobial alternatives. The minimum inhibitory concentrations (MIC) of the three products were determined against 17 antibiotic resistant bacterial clinical isolates from the ocular surface. Using a standard cytotoxicity assay, the products at varying concentrations were evaluated with a corneal fibroblast cell line and a macrophage-like cell line to determine their potential toxic effect in vitro. The commercial ophthalmic solutions, ofloxacin 0.3%, tobramycin 0.3% and gentamicin 0.3% were used as positive controls for the MIC and tobramycin 0.3% was used as positive control for the cytotoxicity assays. For the MIC, Product C showed no inhibition of growth for any organisms, while Products A and B showed inhibition of growth similar to slightly less than the positive controls. For the cytotoxicity assays, Product C exhibited minimal toxicity while Products A and B exhibited toxicity similar to the controls. In conclusion, Product C had no antibacterial activity in these assays, while Products A and B had antibacterial profiles similar to slightly less than common topical ophthalmic antibiotics and cytotoxicity profiles similar to common topical ophthalmic antibiotics. To our knowledge, this is the first report on the antibacterial activity and safety of the cationic steroid antibiotics and superoxidized water.</p></div

Cytotoxicity of ophthalmic products against CCL-60 cells, four 5-minute exposures.

<p>Tobramycin was used as the positive control. Cells were exposed to the commercial products for 5 minutes, 4 separate times. Cell viability was expressed as percentage of absorbance in comparison to the negative control. A compound was considered toxic to the cell line in this experiment if ≤ 95% cell survival was recorded. Toxicity is indicated by (*).</p

Cytotoxicity of ophthalmic products against CCL-60 cells, single 2-hour exposure.

<p>Tobramycin was used as the positive control. Cells were exposed to the commercial products for a single 2-hour exposure. Cell viability was expressed as percentage of absorbance in comparison to the negative control. A compound was considered toxic to the cell line in this experiment if ≤ 95% cell survival was recorded. Toxicity is indicated by (*).</p

Cytotoxicity of ophthalmic products against J774A.1 cells, four 5-minute exposures.

<p>Tobramycin was used as the positive control. Cells were exposed to the commercial products for 5 minutes, 4 separate times. Cell viability was expressed as percentage of absorbance in comparison to the negative control. A compound was considered toxic to the cell line in this experiment if ≤ 95% cell survival was recorded. Toxicity is indicated by (*).</p

Minimum inhibitory concentrations (μg/ml) of Products A, B, C and commercial topical ophthalmic products against bacterial isolates.

<p>Minimum inhibitory concentrations (μg/ml) of Products A, B, C and commercial topical ophthalmic products against bacterial isolates.</p

Table_1_Exploring the antibacterial potential of plant extracts and essential oils against Bacillus thermophilus in beet sugar for enhanced sucrose retention: a comparative assessment and implications.pdf

Sugar beet is one of the greatest sources for producing sugar worldwide. However, a group of bacteria grows on beets during the storage process, leading to a reduction in sucrose yield. Our study focused on identifying common bacterial species that grow on beets during manufacturing and contribute to sucrose loss. The ultimate goal was to find a potential antibacterial agent from various plant extracts and oils to inhibit the growth of these harmful bacteria and reduce sucrose losses. The screening of bacterial species that grow on beet revealed that a large group of mesophilic bacteria, such as Bacillus subtilis, Leuconostoc mesenteroides, Pseudomonas fluorescens, Escherichia coli, Acinetobacter baumannii, Staphylococcus xylosus, Enterobacter amnigenus, and Aeromonas species, in addition to a dominant thermophilic species called Bacillus thermophilus, were found to be present during the manufacturing of beets. The application of 20 plant extracts and 13 different oils indicated that the extracts of Geranium gruinum, Datura stramonium, and Mentha spicata were the best antibacterials to reduce the growth of B. thermophilus with inhibition zones equal to 40, 39, and 35 mm, respectively. In contrast, the best active oils for inhibiting the growth of B. thermophilus were Mentha spicata and Ocimum bacilicum, with an inhibitory effect of 50 and 45 mm, respectively. RAPD-PCR with different primers indicated that treating sugar juice with the most effective oils against bacteria resulted in new recombinant microorganisms, confirming their roles as strong antibacterial products. The characterization of Mentha spicata and Ocimum bacilicum oils using GC/MS analysis identified cis-iso pulegone and hexadecanoic acid as the two main bioactive compounds with potential antibacterial activity. An analysis of five genes using DD-PCR that have been affected due to antibacterial activity from the highly effective oil from Mentha spicata concluded that all belonged to the family of protein defense. Our findings indicate that the application of these pure antibacterial plant extracts and oils would minimize the reduction of sucrose during sugar production.</p