Value of lysozyme agar incorporation and alkaline thioglycollate exposure for the environmental recovery of Clostridium difficile

• Published in: The Journal of hospital infection Vol. 44; no. 1; pp. 65 - 69
• Main Authors: WILCOX, M. H, FAWLEY, W. N, PARNEL, P
• Format: Journal Article
• Language: English
• Published: Kent Elsevier 2000
• Subjects: Agar; Anti-Bacterial Agents; Bacteriological methods and techniques used in bacteriology; Bacteriological Techniques - statistics & numerical data; Bacteriology; Bile Acids and Salts; Biological and medical sciences; Chi-Square Distribution; Clostridium difficile; Clostridium difficile - isolation & purification; Culture Media; Environmental Microbiology; Fundamental and applied biological sciences. Psychology; Microbiology; Muramidase; Thioglycolates; Culture medium; Enzyme; Clostridium difficile; Clostridiales; Agar; Hospital strain; Method; Microbiological investigation; Glycosidases; Clostridiaceae; Microorganism culture; Bacteria; Hydrolases; Environment; Isolation; Hospital; O-Glycosidases; Lysozyme
• ISSN: 0195-6701; 1532-2939
• DOI: 10.1053/jhin.1999.0253

Clostridium difficile is an increasingly prevalent nosocomial pathogen. Environmental contamination by spores is believed to be a major factor propagating the spread of C. difficile. Various approaches including the use of bile salts have been described to enhance the recovery of C. difficile from clinical and environmental specimens. We found that lysozyme (5 mg/L) incorporated into a selective medium containing bile salts significantly increased the recovery of C. difficile from swabs of 197 environmental sites (11% versus 24% samples positive, P< 0.01). Furthermore, in a separate series of experiments additional use of cooked meat broth enrichment significantly enhanced the recovery of C. difficile (35% versus 45%, P = 0.009). Conversely, we found that pre-exposure to alkaline thioglycollate did not improve the yield of C. difficile. Lysozyme incorporation markedly increases the recovery of C. difficile from environmental samples probably by stimulation of spore germination. Our findings suggest that previous attempts to determine the level of environmental C. difficile contamination have markedly underestimated the true prevalence of this pathogen.