Development and application of an in vitro methodology to determine the transit tolerance of potentially probiotic Lactobacillus and Bifidobacterium species in the upper human gastrointestinal tract

Abstract

An in vitro methodology which mimics in vivo human upper gastrointestinal transit was developed. The transit tolerance of potentially probiotic Lactobacillus and Bifidobacterium species was determined by exposing washed cell suspensions at 37°C to a simulated gastric juice (pH 2·0), containing pepsin (0·3% w/v) and sodium chloride (0·5% w/v), and a simulated small intestinal juice (pH 8·0), containing pancreatin USP (1 g l−1) and sodium chloride (5 g l−1), and monitoring changes in total viable count periodically. The methodology was also employed to determine the effect of adding milk proteins (1 g l−1), hog gastric mucin (1 g l−1) and soyabean trypsin‐chymotrypsin inhibitor [SBTCI] (1 g l−1) on transit tolerance. The majority (14 of 15) of isolates lost >90% viability during simulated gastric transit. Only one isolate, Lactobacillus fermentum KLD, was considered intrinsically resistant. The addition of milk proteins, singly and in combination, generally improved gastric transit tolerance. In this regard, two isolates, Lact. casei 212.3 and Bifidobacterium infantis 25962, exhibited 100% gastric transit tolerance in the presence of milk proteins. In general, the addition of hog gastric mucin did not influence simulated gastric transit tolerance of lactobacilli but tended to increase that of bifidobacteria. However, it increased that of Lact. casei 242 and Lact. salivarius 43338 but diminished that of B. bifidum 2715 and B. animalis Bo. Selected bile salts‐resistant isolates were intrinsically tolerant to simulated small intestinal transit. Only Lact. casei F19 and B. adolescentis 15703T showed significant reduction in viability after 240 min. In general, the addition of milk proteins and SBTCI did not affect simulated small intestinal transit tolerance. However, they significantly improved the intrinsic resistance of Lact. casei F19 but diminished that of B. breve 15700T. It is concluded that, whereas the majority of bile salts‐resistant lactobacilli and bifidobacteria may be intrinsically sensitive to gastric transit, they are intrinsically resistant to small intestinal transit. In addition, it is postulated that milk proteins and mucin may function as both buffering agents and inhibitors of digestive protease activity in vivo, thereby protecting ingested bacterial strains during upper gastrointestinal transit.

Potencial probiótico in vitro de bactérias ácido-láticas isoladas de queijo-de-minas artesanal da Serra da Canastra, MG

“…O acúmulo de prótons no meio intracelular pode interferir no funcionamento da membrana celular, prejudicando processos essenciais à sobrevivência celular (Guchte et al, 2002). (Charteris et al, 1998b). A sensibilidade a sais biliares no intestino delgado ocorre, principalmente, pela ação detergente deles à membrana celular constituída de lipídeos e ácidos graxos das bactérias (Guchte et al, 2002 (Charteris et al, 1998b;FAO/WHO, 2002).…”

“…O antibiograma foi realizado em duplicata, com três repetições, de acordo com a técnica adaptada de susceptibilidade a antimicrobianos por difusão da droga em discos (Charteris et al, 1998b). As amostras de microrganismos isolados e selecionados foram cultivadas em ágar MRS (Difco, Detroit, Estados Unidos), em aerobiose (37ºC, 24 a 48h).…”

“…Logo após, foram distribuídos os discos (Oxoid, Basingstoke, Inglaterra) contendo os antimicrobianos (com suas concentrações predeterminadas pelo fabricante de acordo com a orientação da Anvisa, 2005): ceftazidima (30g), clindamicina (2g), ciprofloxacina (5g), eritromicina (15g), gentamicina (10g), oxacilina (1g), penicilina (10U), estreptomicina (30g), tetraciclina (30g) e vancomicina (30g). As placas foram novamente incubadas (37ºC, 24h (Charteris et al, 1998b).…”

Probiotic capsules do not lower plasma lipids in young women and men

“…In vitro simulation has suggested that whereas some species of L. and B. lose viability during gastric transit, ingestion with milk proteins improves their tolerance to the pH of upper GI system (Charteris, 1998). In addition to its potential effect on bacterial viability, milk has been hypothesized to contain components such as 3-hydroxymethyl glutarate and orotic acid that may independently lower cholesterol (Mann, 1977;St-Onge et al, 2000).…”

The effect of Lactobacillus casei and Bifidobacterium breve on antibiotic-associated diarrhea treatment: randomized double-blind clinical trial

“…and Bifidobacterium spp. showed a loss of viability when exposed to the secretions of stomach acid and bile salts 32 . However, an increase of CFU was observed in these bacteria in the stools of individuals who ingested them, which could act beneficially in patients [13][14]33 .…”