Simplified procedure for the routine isolation of Clostridium difficile from faeces

Area of Science:

• Clinical microbiology
• Infectious diseases
• Gastroenterology

Background:

• Clostridium difficile is a significant cause of antibiotic-associated diarrhea.
• Accurate and efficient isolation of Clostridium difficile from fecal samples is crucial for diagnosis and treatment.
• Selective culture methods are essential for isolating Clostridium difficile from complex fecal matrices.

Purpose of the Study:

• To compare the efficacy of a 50% alcohol procedure (AP) with a selective agar (SA) for Clostridium difficile isolation.
• To evaluate the performance of a modified AP with open-bench manipulations.
• To determine the sensitivity and specificity of both methods in detecting Clostridium difficile in clinical fecal samples.

Main Methods:

• A total of 266 fecal samples were analyzed.
• Samples were cultured using both a selective agar (SA) and a 50% alcohol procedure (AP).
• A modified AP protocol was also tested, with pre-incubation steps performed on an open bench.

Main Results:

• Selective agar (SA) detected 77 out of 82 positive samples (94%), while the alcohol procedure (AP) detected 72 samples (88%).
• SA identified 10 samples missed by AP (12%), and AP identified 5 samples missed by SA (6%).
• The modified AP detected 16 out of 18 positive samples (89%), compared to 100% detection by SA.

Conclusions:

• Selective agar (SA) demonstrates superior sensitivity for Clostridium difficile isolation compared to the alcohol procedure (AP).
• The alcohol procedure (AP), even when modified, shows a lower detection rate for Clostridium difficile.
• SA is recommended as a more effective method for the selective isolation of Clostridium difficile from fecal samples.