Antimicrobial activity of lacticin 3147 against clinical Clostridium difficile strains

• Published in: Journal of medical microbiology Vol. 56; no. 7; pp. 940 - 946
• Main Authors: Rea, Mary C, Clayton, Evelyn, O'Connor, Paula M, Shanahan, Fergus, Kiely, Barry, Ross, R. Paul, Hill, Colin
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.07.2007; Society for General Microbiology
• Subjects: Bacteroides; Biological and medical sciences; Clostridium; Clostridium difficile; Fundamental and applied biological sciences. Psychology; Infectious diseases; Lactobacillus; Medical sciences; Microbiology; Microbiology; Bacteriocin; Clostridiaceae; Clostridium difficile; Clostridiales; Bacteria; Antimicrobial agent; Strain
• ISSN: 0022-2615; 1473-5644
• DOI: 10.1099/jmm.0.47085-0

1 Teagasc, Biotechnology Centre, Moorepark Food Research Centre, Moorepark, Fermoy, Cork, Ireland 2 Alimentary Pharmabiotic Centre, University College, Cork, Ireland 3 Department of Medicine, University College, Cork, Ireland 4 Alimentary Health, Kinsale, Cork, Ireland 5 Department of Microbiology, University College, Cork, Ireland Correspondence R. Paul Ross paul.ross{at}teagasc.ie Received 17 November 2006 Accepted 27 February 2007 Clostridium difficile -associated diarrhoea (CDAD) is the most common hospital-acquired diarrhoea, and is a major type of gastroenteritis infection in nursing homes and facilities for the elderly. In this study the antimicrobial activity of the two-component lantibiotic, lacticin 3147, against a range of genetically distinct C. difficile isolates was studied. The bacteriocin exhibited an MIC 50 of 3.6 µg ml –1 for 10 genetically distinct C. difficile strains isolated from healthy subjects, inflammatory bowel disease patients and culture collection strains. In time-kill studies, 10 6 c.f.u. ml –1 C. difficile ATCC 42593 and CDAD isolate DPC 6220 were killed within 120 or 20 min incubation, respectively, at a concentration of 6 µg lacticin ml –1 . Interestingly, addition of lacticin 3147 to exponentially growing cells of C. difficile ATCC 43593 caused rapid lysis of the cells after an initial lag phase, as measured by the concomitant release of the intracellular enzyme, acetate kinase. The addition of a food-grade, milk-based lacticin containing powder to faecal fermentation demonstrated that lacticin is effective in completely eliminating 10 6 c.f.u. C. difficile ml –1 from a model faecal environment within 30 min when present at concentrations as low as 18 µg ml –1 . While other culturable microflora such as total anaerobes, bacteroides, total non-spore-forming anaerobes and total Gram-negative anaerobes were unaffected, populations of lactobacilli and bifidobacteria were reduced by 3 log cycles at bacteriocin levels sufficient to eliminate over 10 6 C. difficil e. In light of these findings, the potential of lacticin 3147 for treatment of CDAD is discussed. Abbreviations: AU, activity unit; CDAD, Clostridium difficile -associated diarrhoea; WDA, well diffusion assay.