A probiotic supplement, Lactobacillus rhamnosus GG, and kefir separately can improve mood and exhibit potential anti-depressant-like activities in mice

Depression is a common psychiatric disorder that can be continuous or recurrent. It has been previously reported that intestine probiotics play an essential role in the bidirectional communication of the intestine and brain. This study aims to investigate the antidepressant effects of kefir, a probiotic supplement, and Lactobacillus rhamnosus GG and their potentials in depression-like behaviour treatment in two-week and four-week treatments. In the present study, BALB/c mice were used for this purpose. The saline- and fluoxetine-treated groups were designed as negative and positive control groups, respectively. The forced swimming and tail suspension tests have been performed to assess the level of depression-like activity. We have observed that two-week treatment reduces the duration of depression-like activities, and four-week treatment enhances the antidepressant properties. Overall, our results suggest that kefir, L. rhamnosus GG, and the investigated probiotic supplement have antidepressant-like properties.

Identification and characterization of probiotic lactic acid bacteria isolated from traditional persian pickled vegetables

Background: The pickle, a traditional fermented product, is popular among Iranians. Much research has been conducted worldwide on this food group. Due to a lack of related data in Iran, this study was conducted to isolate and identify dominant lactic acid bacteria (LAB) in pickles and salted pickles. Materials and methods: Seventy samples were collected from different regions of Iran. The isolated bacteria were identified as LAB by Gram staining and catalase by using MRS agar. Then, those strains were identified at the species level by physiological tests (e.g., gas production from glucose, arginine hydrolysis, CO2 production from glucose in MRS broth, carbohydrate fermentation) and growth at temperatures of 15°C, 30°C, and 45°C in MRS broth for 3 days. The probiotic characteristics of these bacteria were studied using acid and bile tolerance. The corresponding results were verified using PCR analyses of the 16S rDNA region. Results: 114 presumptive lactic acid bacteria (LAB) with Gram-positive and catalase-negative properties were obtained from the samples. The results revealed that all isolated bacteria were identfied as Lactobacillus (L.) plantarum, L. brevis, L. pentosus, L. casei, L. paracasei and Leuconostoc mesenteroides. The predominant LAB in these pickles was L. plantarum, which was isolated from most of the samples. Among the 114 LAB, 7 isolated species have probiotic potential. Six out of seven were recognized as L. plantarum and one remained unidentifiable by biochemical testing. PCR analysis and sequencing of the 16S rDNA region using 27f and 1522r primers showed that all of the probiotic strains were L. plantarum. Conclusion: The results of this study showed that the dominant LAB in traditional Persian pickled vegetables are L. plantarum, L. brevis, L. pentosus, L. casei, L. paracasei, and Leuconostoc mesenteroides. Moreover, L. plantarum was recognized as a probiotic species in pickled vegetables. The raw data obtained from this study can be used in the pickling industry to improve the nutritional value of products.

Inhibitory effect of Lactobacillus plantarum and Lb. fermentum isolated from the faeces of healthy infants against nonfermentative bacteria causing nosocomial infections

Nosocomial infection constitutes a major public health problem worldwide. Increasing antibiotic resistance of pathogens associated with nosocomial infections has also become a major therapeutic challenge for physicians. Thus, development of alternative treatment protocols, such as the use of probiotics, matters. The aim of this research was to determine the antagonistic properties of Lactobacillus plantarum and Lb. fermentum isolated from the faeces of healthy infants against nonfermentative bacteria causing nosocomial infections. One hundred five samples of nosocomial infections were collected and processed for bacterial isolation and antimicrobial susceptibility testing following standard bacteriologic techniques. The antibiotic susceptibility test was performed by the disk diffusion method, and antagonistic effect of Lactobacillus strains was investigated by well diffusion method. Of 105 samples, a total of 29 bacterial strains were identified as nonfermentative bacteria, including 17 Acinetobacter baumannii and 12 Pseudomonas aeruginosa. A. baumannii showed high resistance to tested antibiotics except ampicillin/sulbactam, and P. aeruginosa showed resistance to ampicillin/sulbactam and gentamicin and sensitive to amikacin and meropenem. Lb. plantarum had antagonistic properties against both A. baumannii and P. aeruginosa strains. Lb. plantarum had considerable effects on preventing the growth of A. baumannii and P. aeruginosa strains. However, further research is needed to better understanding of these effects on P. aeruginosa.