Antimicrobial activity of yeasts against some pathogenic bacteria

Abstract

Aim:This study was designed to isolate and identify yeast species from milk and meat products, and to test their antimicrobial activity against some bacterial species.Materials and Methods:A total of 160 milk and meat products samples were collected from random sellers and super markets in New Damietta city, Damietta, Egypt. Samples were subjected to yeast isolation procedures and tested for its antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. In addition, all yeast species isolates were subjected to polymerase chain reaction (PCR) for detection of khs (kievitone hydratase) and pelA (pectate degrading enzyme)genes.Results:The recovery rate of yeasts from sausage was 20% (2/10) followed by kareish cheese, processed cheese, and butter 10% (1/10) each as well as raw milk 9% (9/100), and fruit yoghurt 30% (6/20). Different yeast species were recovered, namely, Candida kefyr (5 isolates), Saccharomyces cerevisiae (4 isolates), Candida intermedia (3 isolates), Candida tropicalis (2 isolates), Candida lusitaniae (2 isolates), and Candida krusei (1 isolate). khs gene was detected in all S. cerevisiae isolates, however, pelA gene was not detected in all identified yeast species. Antimicrobial activity of recovered yeasts against the selected bacterial species showed high activity with C. intermedia against S. aureus and E. coli, C. kefyr against E. coli, and C. lusitaniae against S. aureus. Moderate activities were obtained with C. tropicalis, C. lusitaniae, and S. cerevisiae against E. coli; meanwhile, all the tested yeasts revealed a very low antimicrobial activity against P. aeruginosa.Conclusion:The obtained results confirmed that some kinds of yeasts have the ability to produce antimicrobial compounds that could inhibit some pathogenic and spoilage bacteria and these antimicrobial activity of yeasts enables them to be one of the novel agents in controlling spoilage of food.

Anti-Biofilm Properties of Saccharomyces cerevisiae CNCM I-3856 and Lacticaseibacillus rhamnosus ATCC 53103 Probiotics against G. vaginalis

“…Given that we recently demonstrated that S. cerevisiae CNCM I-3856 (GI) is unable to co-aggregate with G. vaginalis [ 49 ], it is possible that S. cerevisiae CNCM I-3856 inhibition of G. vaginalis biofilm formation can be ascribed to biological instead of mechanical effects. Indeed, previous studies demonstrated that members of the Saccharomyces genus can produce extracellular protease and other compounds able to inhibit the growth of many pathogenic bacterial species [ 82 , 83 ]. In addition, given that the presence of the sialidase gene is associated with G. vaginalis biofilm formation [ 84 ], the capacity of S. cerevisiae CNCM I-3856 in inhibiting sialidase activity [ 49 ] could account for the observed effect.…”

“…First, S. cerevisiae CNCM I-3856 can degrade the extracellular matrix by secreting enzymes [ 82 ] such as amylase, protease, and lipase that favor penetration of the yeast into the biofilm, allowing it to displace G. vaginalis from the abiotic surface. Second, the probiotic can have an antimicrobial activity by secreting specific compounds [ 82 , 83 ].…”

Gc-MS Analysis of Bioactive Compounds and Antimicrobial Activity of Cryptococcus Rajasthanensis Ky627764 Isolated From Bombyx Mori Gut Microflora.

“…The chloroform extract showed higher antimicrobial activity as compared to the ethyl acetate extract which may be attributed to the more number of bioactive chemical constituents in the chloroform extract as compared to the ethyl acetate extract evaluated by GC-MS analysis. Several research studies have previously reported the antimicrobial nature of yeasts especially in biopreservation of food and yeasts as biocontrol agents (Younis et al, 2017; Mewa-Ngongang et al, 2017; Knight and Witzgall, 2013) but the antimicrobial nature of yeasts in light of its chemical constituents has not been given much importance. Thus this study reports the probability of antimicrobial nature of the yeast isolated from insect gut with regards to its bioactive chemical constituents.…”

The Use of Selected Bacteria and Yeasts to Control Vibrio spp. in Live Food

“…Then, with the achievement of new findings on probiotics and how they work, scientists began to use these beneficial bacteria to improve the growth performance of animals [13]. Probiotics have several benefits including efficient adherence to the intestinal epithelial cells to reduce or prevent the colonization of pathogens [12,14], competitive growth with pathogens [3], and also the production of metabolites to inhibit or kill pathogens [15,16]. Probiotics, defined as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host”, constitute a potential tool in the reduction of mortality in the rearing of aquatic organisms [12].…”