Lee Y., Paek K., Park J., Hong H., Shin E.
Department of Chemistry, Soongsil UniversityR&D Center, Namyang Dairy Produts, Co.CCARM, Seoul Womens University, South Korea

Intestinal microflora is closely related with human health and diseases influencing intestinal immune response, obesity, and even psychology. Its composition is closely influenced by food, age, regions, and human races. We isolated various lactobacillus and bifidobacteria from healthy people over 80 years old and assayed their MICs to various antimicrobial agents as the first step to develop a safe probiotic.

Eight villages with more than 200 residents were selected based on previous studies. More than 10 fecal samples in each village were provided by healthy people older than 80 with regular bowl movement. Lactobacillus and Bifidobacteria were isolated and identified with 16S rRNA sequencing by Bionix (Seoul, Korea). MICs of lactobacillus were performed against 15 antimicrobial agents (ampicillin, chloroamphenicol, clindamycin, ciprofloxacin, erythromycin, gentamicin, kanamycin, lincosamide, neomycin, rifampicin, synercid, streptomycin, tetracycline, trimethoprim, vancomycin) while MICs of bifidobacteria were assayed against 8 antimicrobial agents (ampicillin, clindamycin, chloramphenicol, erythromycin, gentamycin, streptomycin, tetracycline, vancomycin). Minimal inhibitory concentrations (MICs) were assayed with the liquid dilution method using LSM for lactobacillus and LSM with cysteine for bifidobacteria following the ISO guideline (2010).

Total 104 lactobacillus and 27 bifibacteria were isolated from 79 people. Isolated lactobacillus belonged to 17 species and bifidobacteria belonged to 5 species. These were L. acidicipiscis (1 isolate), L. acidophilus (1 isolate), L. animalis (1 isolate), L. brevis (3 isolates), L. crispatus (8 isolates), L. fermentum (29 isolates), L. garvieae (2 isolates), L. gasseri (3 isolates), L. graminis (1 isolate), L. paracasei (20 isolates), L. paracasei subsp. Tolerans (9 isolates), L. pentopsus (1 isolate), L. plantarum subsp. Plantarum (3 isolates), L. rhamnosus (4 isolates), L. saerimneri (4 isolates), L. sakei sub. Sakei (13 isolates), L. salivarius (1 isolates) and B. longum subsp. Infantis (13 isolates), B. longum subsp. Longum,(9 isolates), B. faecale (1 isolate), B. pseudocatenulatum (2 isolates) B. adolescentis (2 isolates). Number of susceptible isolates of lactobacillus were 14 (13%) and these were: 6 isolates (21%) of L. fermentum; 4 isolates (14%) of 29 L. paracasei; 2 isolates (50%) of L. rhamnosus; 2 isolates (100%) of L. plantarum. Resistant isolates which were resistant to at least more than one antimicrobial agents were : 2 isolates to tetracyclie; 1 isolates to erythromycin, 1 isolates to clindamycin, 3 isolates to chloramphenicol; 1 isolates to ampicillin. Number of susceptible isolates of bifidobacteria were 18 (67%): 8 isolates of B. longum subsp. Infantis; 6 isolates of B. longum subsp. Longum, 1 isolates of B. faecale, 1 isolate of B. pseudocatenulatum, and 2 isolates of B. adolescentis. Number of resistant bifidobacteria were 9: 1 isolates resistant to both tetracycline and chloramphenicol; 1 isolates to tetracycline; 2 isolates to erythromycin; 1 isolates to clindamycin; 2 isolates to chloroamphenicol; 1 isolates to ampicillin. B. faecale and adolescentis were all susceptible while 1 isolate (50%) of B. pseudocatenulatum was resistant to erythromycin.

Only a small percentage (13%) of lactobacillus while a large proportion (67%) of bifidobacteria showed antimicrobial susceptibility. For development of a probiotic, antimicrobial susceptibility should be assayed to develop a safe probiotic.

Keywords: LAB, Antimicrobial susceptibility, Bifidobacterium Healthy elderly people, Korean longevity village, Probiotics

Lee Y., et al. (2016). Antimicrobial susceptibility of Lactobacillus and Bifidobacterium isolated from healthy elderly people living in the Korean longevity village. Conference Proceedings of IPC2016. Paper presented at the International Scientific Conference on Probiotics and Prebiotics, Budapest (p. 43.). IPC2016

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