title: In vitro inhibition of Clostridium difficile by commercial probiotics: A microcalorimetric study.
abstract: The aim of the study was to investigate the influence of some commercial probiotics on the growth of Clostridium difficile using isothermal microcalorimetry, a technique which can monitor the real time growth of bacteria. Commercial probiotic strains and products, Lactobacillus acidophilus LA-5®, Bifidobacterium lactis BB-12®, Probio 7®and Symprove™ were co-cultured with C. difficile in Brain Heart Infusion (BHI) broth supplemented with 0.1% (w/v) l-cysteine hydrochloride and 0.1% (w/v) sodium taurocholate and monitored in the microcalorimeter. Pseudomonas aeruginosa NCIMB 8628 was also co-cultured with C. difficile and studied. The results indicated inhibition of C. difficile by the probiotics. The inhibition of C. difficile was shown to be pH-dependent using neutralized and unmodified cell free supernatant (CFS) produced by the probiotic strains. However, concentrated CFS of the probiotics also inhibited the intestinal pathogen in a non pH-dependent manner, likely due to specific antimicrobial substances produced. The results also indicated that C. difficile growth was greatly influenced by the presence of sodium taurocholate and by the pH of the medium. A medium pH of between 6.45 and 6.9 demonstrated maximum growth of the organism in the microcalorimeter.
authors.affiliation: UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom. Electronic address: mansa.fredua-agyeman.11@ucl.ac.uk.
authors.forename: Mansa
authors.initials: M
authors.lastname: Fredua-Agyeman
authors.affiliation: UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom. Electronic address: p.stapleton@ucl.ac.uk.
authors.forename: Paul
authors.initials: P
authors.lastname: Stapleton
authors.affiliation: UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom. Electronic address: a.basit@ucl.ac.uk.
authors.forename: Abdul W
authors.initials: AW
authors.lastname: Basit
authors.affiliation: UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom. Electronic address: abeezer@btinternet.com.
authors.forename: Anthony E
authors.initials: AE
authors.lastname: Beezer
authors.affiliation: UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom. Electronic address: s.gaisford@ucl.ac.uk.
authors.forename: Simon
authors.initials: S
authors.lastname: Gaisford
mesh_terms: D000898:Antibiosis; D001430:Bacteriocins / Q000096:biosynthesis / Q000494:pharmacology; D001644:Bifidobacterium / Q000254:growth & development* / Q000378:metabolism; D002151:Calorimetry; D016360:Clostridioides difficile / Q000254:growth & development* / Q000378:metabolism; D018920:Coculture Techniques; D003470:Culture Media; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus / Q000254:growth & development* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D019936:Probiotics / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000254:growth & development; D013656:Taurocholic Acid / Q000737:chemistry
chemical_list: D001430:Bacteriocins; D003470:Culture Media; D013656:Taurocholic Acid
keywords: Clostridium difficile; Co-culture; Inhibition; Isothermal microcalorimetry; Probiotics