Typing scheme for Clostridium difficile: its application in clinical and epidemiological studies

Area of Science:

• Microbiology
• Infectious Diseases
• Epidemiology

Background:

• Clostridium difficile diarrhoeal disease epidemiology is hampered by the absence of a reliable typing scheme.
• Effective strain differentiation is crucial for understanding transmission dynamics and controlling outbreaks.

Purpose of the Study:

• To develop and validate a protein-based typing method for Clostridium difficile.
• To establish distinct C. difficile groups and investigate their epidemiological associations.

Main Methods:

• Incorporation of sulfur-35-labeled methionine into cellular proteins.
• Separation of labeled proteins using sodium dodecyl sulfate/polyacrylamide gel electrophoresis (SDS-PAGE).
• Analysis of protein profiles to differentiate C. difficile strains.

Main Results:

• A typing scheme was established, differentiating C. difficile into nine distinct groups.
• 98% of 250 clinical strains from four hospitals were successfully typable.
• Group X was the most prevalent, associated with outbreaks of pseudomembranous and antibiotic-associated colitis.
• Groups A-D were frequently isolated from mothers and neonates.
• Outbreaks in oncology and orthopaedic wards involved specific strains (Group X and E) found in patients and their environment, indicating cross-infection and hospital acquisition.

Conclusions:

• The developed protein electrophoresis typing method is effective for epidemiological studies of Clostridium difficile.
• Distinct C. difficile groups have different epidemiological associations, including hospital-acquired infections and mother-infant transmission.
• Evidence supports cross-infection and environmental contamination as key factors in C. difficile outbreaks within healthcare settings.