This retrospective study was conducted at the Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China. Diarrhea was defined as three or more loose stools within 24 hours. Stool samples collected from neurosurgery department inpatients with diarrhea were submitted to the clinical microbiology laboratory for isolation of C. difficile. Inpatients with diarrhea, whose stool samples were positive for both C. difficile culture and toxin genes (tcdA and/or tcdB) and without evidence of other pathogens of diarrhea (including Shigella, nontyphoidal Salmonella, Campylobacter and Shiga toxin-producing Escherichia coli), were diagnosed as CDI.
Approximately 0.5 mL (0.5 g) of stool was mixed with 0.5 mL of 95% ethanol for 30 min at room temperature for spore selection before anaerobic isolation of C. difficile on selective cycloserine–cefoxitin–taurocholate agar (CCFA-TA; Oxoid) plates supplemented with 7% sheep blood incubated at 35°C for 48 h with anaerobic incubation (80% N2, 10% H2, 10% CO2). The C. difficile isolates were confirmed by matrix-assisted laser desorption ionization–time-of-flight mass spectrometry using a Bruker Daltonics Microflex LT system (Bruker Daltonik GmbH, Bremen, Germany).
Approximately 0.5 mL (0.5 g) of stool was mixed with 0.5 mL of 95% ethanol for 30 min at room temperature for spore selection before anaerobic isolation of C. difficile on selective cycloserine–cefoxitin–taurocholate agar (CCFA-TA; Oxoid) plates supplemented with 7% sheep blood incubated at 35°C for 48 h with anaerobic incubation (80% N2, 10% H2, 10% CO2). The C. difficile isolates were confirmed by matrix-assisted laser desorption ionization–time-of-flight mass spectrometry using a Bruker Daltonics Microflex LT system (Bruker Daltonik GmbH, Bremen, Germany).