Lamiaa A. Al-Madboly

Potent antagonistic activity of Egyptian Lactobacillus plantarum against multiresistant and virulent food-associated pathogens.

Recent years have shown a growing interest to replace the administration of antibiotics with the application of probiotics. The aim of our investigation was to screen for promising strains with broad antimicrobial activity and also more resistant to the challenges met in the gastrointestinal tract. In our study, only 32 out of 50 (64%) probiotic isolates showed antagonistic activity against certain major extensively and pandrug-resistant Gram-positive and -negative food-borne pathogens. Fifteen L. plantarum isolates had a broad antibacterial spectrum. Among these isolates, only five presented potent antibacterial activity relative to previous studies. The recorded inhibition zone diameter ranged from 25 to 44 mm. Pronounced cell-free supernatant activities (6400–25,600 AU/ml) were commonly detected at the end of the logarithmic phase at 37°C. A marked increase in the range of activity (12,800–51,200 AU/ml) was recorded after the addition of 0.9% Na Cl to the media. Moreover, subjecting these isolates to different stressors, including high temperature, low pH, and different concentrations of bile and Na Cl, revealed different responses, and only two out of the five L. plantarum isolates showed marked resistance to all of the stress factors. Accordingly, this study highlights the intense and broad antagonistic activity induced by L. plantarum against various food associated pathogens, and their ability to resist different stressors suggests that they can be used in the food and pharmaceutical industry.

Synergistic Effect of Newly Introduced Root Canal Medicaments; Ozonated Olive Oil and Chitosan Nanoparticles, Against Persistent Endodontic Pathogens

This study was conducted to investigate the antimicrobial-biofilm activity of chitosan (Ch-NPs), silver nanoparticles (Ag-NPs), ozonated olive oil (O3-oil) either separately or combined together against endodontic pathogens. While testing the antimicrobial activity, Ch-NPs showed the least minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values exerting eightfold higher bactericidal activity than O3-oil against both Enterococcus faecalis and Streptococcus mutans as well as fourfold higher fungicidal activity against Candida albicans. Antimicrobial synergy test revealed synergism between O3-oil and Ch-NPs against the test pathogens (FIC index ≤ 0.5). Ch-NPs was superior at inhibiting immature single and mixed-species biofilm formations by 97 and 94%, respectively. Both of O3-oil and Ch-NPs had a complete anti-fibroblast adherent effect. The safety pattern results showed that O3-oil was the safest compound, followed by Ch-NPs. The double combination of Ch-NPs and O3-oil reduced the mature viable biofilm on premolars ex vivo model by 6-log reductions, with a fast kill rate, indicating potential use in treating root canals. Therefore, the double combination has the potential to eradicate mature mixed-species biofilms and hence it is potent, novel and safe.

Miconazole-Urea in a Buccal Film as a New Trend for Treatment of Resistant Mouth Fungal White Patches

A growing concern about Candida albicans is the emergence of high incidence of resistance against antifungal agents, which requires searching for new medications or improving the response to the existing members. The objective of this work was to evaluate the effectiveness of the miconazole in the absence and presence of urea, as a penetration enhancer, against C. albicans. In addition to, formulating both of them in a polymer film to be used topically for treatment of mouth fungal white patches caused by C. albicans. A synergistic effect was recorded between this imidazole and urea against the test strain. Miconazole MIC (32 mg/L) was dramatically reduced to 0.0625 mg/L following combination with urea. Transmission electron microscopy explained the mechanisms of action mediated by the test agents. Minimal fungicidal dose of miconazole combined with urea showed early apoptotic cells with condensed chromatin and small blebs. Cytoplasmic leakage and necrosis in some cells was observed at high fungicidal dose. Buccal bioadhesive films were prepared using increasing values of the drug MIC and urea. The physicochemical characters of the prepared films including; film weight, thickness, swelling index, drug content, folding endurance, surface pH, bioadhesion force and time and drug release kinetics, were studied. Microbiological evaluation of all prepared films showed an increase in the inhibition zone diameters for films containing increasing concentrations of both miconazole and urea in a concentration-dependent manner (30–40 mm) compared to miconazole alone (18 mm). Based on our results, the prepared films are promising for buccal administration of miconazole/urea showing synergistic effect for treatment of C. albicans infection.

Case Report of Urethritis in a Male Patient Infected with Two Different Isolates of Multiple Drug-Resistant Neisseria gonorrhoeae

We report a brief description of a case suffering from bacterial urethritis, conjunctivitis, and arthritis, caused by two different isolates of multiple drug-resistant Neisseria gonorrhoeae. Initial diagnosis was dependent on the patient history, clinical findings, symptoms, and the bacteriological data. Polymerase chain reaction confirmed the identification of the pathogens. Random amplified polymorphic DNA revealed two different patterns. Susceptibility testing was performed using Kirby–Bauer disk diffusion method and the minimum inhibitory concentration was also determined. It revealed multiple drug resistance associated with β-lactamase production. Only gentamicin, rifampicin, and azithromycin were active against the test pathogens. A dual therapy was initiated using gentamicin as well as azithromycin to treat the possible co-infection with Chlamydia trachomatis. Complete recovery of the patient achieved with resolved symptoms a week later.

Optimization of Reduced Glutathione Production by a Lactobacillus plantarum Isolate Using Plackett–Burman and Box–Behnken Designs

In this work, we aim to optimize the production of reduced glutathione (GSH) synthesized intracellularly by a food-grade microorganism through a statistical approach. Using a colorimetric method, 25 Lactobacillus plantarum isolates were screened in an attempt to find a GSH-producing strain. It was found that 36% of the tested isolates showed positive result. Isolate (L7) was found to produce 152.61 μM glutathione per gram which was the highest amount produced intracellularly. Accordingly, the later isolate was selected for the optimization process using Plackett–Burman and Box–Behnken designs. Temperature, amino acids, and urea were found to be the most significant independent variables. Following data analysis, the composition of the optimized medium was De Man-Sharp-Rogosa broth as a basal medium supplemented with NaCl (5%), H2O2 (0.05%), sodium dodecyl sulfate (0.05%), amino acids (0.0281%), and urea (0.192%). The pH of the medium was adjusted to 8 and incubated for 24 h at 40°C. The GSH amount was increased by 10-fold (851%) using the optimized medium. Hence, our optimization design estimated the biotechnological potential of L. plantarum (L7) for the production of GSH in the industry.