Abstract
For screening excellent lactic acid bacteria (LAB) strains to inhibit enterotoxigenic Escherichia coli (ETEC) K88, inhibitory activities of more than 1100 LAB strains isolated from different materials, and kept in the lab, were evaluated in this study. Nine strains with inhibition zones, at least 22.00 mm (including that of a hole puncher, 10.00 mm), and good physiological and biochemical characteristics identified by 16S DNA gene sequencing and recA gene multiple detection, were assigned to Lactobacillus (L.) plantarum subsp. plantarum (5), L. fermentum (1), L. reuteri (1), Weissella cibaria (1) and Enterococcus faecalis (1), respectively. As investigated for their tolerance abilities and safety, only strain ZA3 possessed high hydrophobicity and auto-aggregation abilities, had high survival rate in low pH, bile salt environment, and gastrointestinal (GI) fluids, was sensitive to ampicillin, and resistant to norfloxacin and amikacin, without hemolytic activity, and did not carry antibiotic resistance genes, but exhibited broad spectrum activity against a wide range of microorganisms. Antibacterial substance may attribute to organic acids, especially lactic acid and acetic acid. The results indicated that the selected strain L. plantarum subsp. plantarum ZA3 could be considered a potential probiotic to inhibit ETEC K88 in weaned piglets for further research.
Highlights
Enterotoxigenic Escherichia coli (ETEC) K88 is a pathogenic variant of Escherichia coli that colonizes the surface of gastrointestinal cells when K88 infects the host and produces enterotoxins
This study evaluates the probiotic properties of the lactic acid bacteria (LAB) strains isolated from different sources by determining their inhibitory activities to enterotoxigenic Escherichia coli (ETEC) K88
Strains were uniformly rebranded as the ZA series for better documentation and preservation) with inhibition zones of at least 18.00 mm were selected for further study
Summary
Enterotoxigenic Escherichia coli (ETEC) K88 is a pathogenic variant of Escherichia coli that colonizes the surface of gastrointestinal cells when K88 infects the host and produces enterotoxins. This disrupts intestinal cellular electrolyte homeostasis, leading to fluid loss and, to secretory diarrheal disease in newborns and piglets [1,2,3]. Post-weaning diarrhea (PWD) caused by ETEC K88 has a high mortality rate. Antibiotics have been long used to reduce diarrhea and enhance growth performance in weaned piglets, while long-term use of antibiotics caused the emergence of resistant strains of animal and food-borne pathogens and further intestinal microbial imbalance, according to announcement No 194 of the Ministry of Agriculture and Rural Affairs. I.e., zinc oxide (ZnO), have traditionally been used to mitigate post-weaning ETEC-F4 diarrhea [5,6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
