The emergence of antibiotic-resistant and food-spoilage microorganisms has renewed efforts to identify safe and natural alternative agents of antibiotics such as probiotics. The aim of this study was the isolation of lactobacilli as potential probiotics from local dairy products with broad antibacterial and anti-biofilm activities against antibiotic-resistant strains of Pseudomonas aeruginosa and determination of their inhibition mechanism. Antibiotic susceptibility and classification of acquired resistance profiles of 80 P. aeruginosa strains were determined based on Centers for Disease Control and Prevention (CDC) new definition as multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) followed by antibacterial assessment of lactobacilli against them by different methods. Among the 80 P. aeruginosa strains, 1 (1.3%), 50 (62.5%), and 78 (97.5%) were PDR, XDR, and MDR, respectively, and effective antibiotics against them were fosfomycin and polymyxins. Among 57 isolated lactobacillus strains, two strains which were identified as Lactobacillus fermentum using biochemical and 16S rDNA methods showed broad inhibition/killing and anti-biofilm effects against all P. aeruginosa strains. They formed strong biofilms and had bile salts and low pH tolerance. Although investigation of inhibition mechanism of these strains showed no bacteriocin production, results obtained by high-performance liquid chromatography (HPLC) analysis indicated that their inhibitory effect was the result of production of three main organic acids including lactic acid, acetic acid, and formic acid. Considering the broad activity of these two L. fermentum strains, they can potentially be used in bio-control of drug-resistant strains of P. aeruginosa.

Background: Diarrhea is a well-recognized side effect associated with pelvic radia on; however, there is not any effec ve common treatment for radia on-induced diarrhea. A popular alterna ve is probio cs, which have been used in several gastrointes nal disorders. Probio cs are live microbial food supplements. Furthermore, honey is a puta ve nutri onal with a variety of health effects, including an bacterial, an oxidant, an-inflammatory and prebio c. The present study evaluated the effects of probio c with or without honey on radia on-induced diarrhea. Materials and Methods: Sixty-seven adult pa ents with pelvic cancer underwent radiotherapy for four weeks. They randomized to receive probio c (n = 22), probio c plus honey (n = 21) or placebo (n = 24) from one week before radiotherapy for five weeks. Diarrhea grade and stool consistency score were recorded weekly according to the Common Toxicity Criteria system and the Bristol scales, respec vely. Results: The results showed a decrease in the daily number of bowel movements (p = 0.003 and 0.006), diarrhea grade (p = 0.001 and 0.001) and the need for an diarrheal medica on (p = 0.021 and 0.041) also an increase in the stool consistency (p = 0.004 and 0.005) in pa ents who either used probio c or probio c plus honey (respec vely), these were significant in weeks 4 and 5 of treatment. Conclusion: Probio cs with or without honey can reduce the incidence of radia on-induced diarrhea and the need for an diarrheal medica on.

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There were high levels of antibiotic resistance and a high frequency of multi-drug resistance and extensive-drug resistance profiles, as well as highly prevalent blaNDM-1 genes in the bacteria investigated.

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The aim of this study was to evaluate the probiotic potential of lactic acid bacteria (LAB) strains isolated from Horreh. Some probiotic properties, e.g., resistance to acid, bile tolerance, antibacterial activity, and antibiotic susceptibility, were investigated. A total of 140 Gram-positive and catalase-negative isolates from Horreh were subjected to identification and grouping by cultural methods and the 16S rRNA sequencing. The new isolates were identified to be Lactobacillus (fermentum, plantarum, and brevis) Weissella cibaria, Enterococcus (faecium and faecalis), Leuconostoc (citreum and mesenteroides subsp. mesenteroides) and Pediococcus pentosaceus. Probiotic potential study of LAB isolates showed that Lb. plantarum and Leu. mesenteroides subsp. mesenteroides isolates were able to grow at pH 2.5 and 3.5. Lactobacillus plantarum (isolate A44) showed the highest cell hydrophobicity (84.5%). According to antibacterial activity tests, Listeria innocua and Staphylococcus aureus were the most sensitive indicators against the selected LAB strains, while Escherichia coli and Bacillus cereus were the most resistant. In addition, all the isolated LAB species were resistant to vancomycin. The results of the present study suggested that the Lactobacillus fermentum and plantarum isolated from Horreh, characterized in this study, have potential use for industrial purposes as probiotics.