Evaluation of the Use of Groin Cultures for Detection of Asymptomatic Carriers of Clostridium difficile

Background: Asymptomatic rectal carriers of Clostridium difficile may contribute to dissemination of spores. It is not known if methods that are less invasive than rectal swabs can be used to identify carriers or to predict those who present the greatest risk for transmission.

Objective: To evaluate the use of groin cultures to identify asymptomatic rectal carriers of C. difficile, and to test that hypothesis that carriers with positive groin cultures have increased frequency of commonly examined skin sites.

Methods:  For asymptomatic carriers of C. difficile identified through rectal surveillance cultures, groin and chest/abdomen swabs were cultured for C. difficile. The proportions of positive chest/abdomen cultures were compared for carriers with or without positive groin cultures. 

Results: Of 39 asymptomatic rectal carriers, 19 (49%) had positive groin cultures. Twelve of 19 (63%) asymptomatic carriers with positive groin cultures had concurrent contamination of their chest and/or abdomen versus 2 of 20 (10%) carriers with negative groin cultures (P =0.0008). Eight of 12 (67%) carriers with positive groin cultures had >4 logs of C. difficile in stool versus 2 of 20 (10%) carriers with negative groin cultures (P =0.04). Of 18 CDI patients studied, 14 (78%) had positive groin cultures; all 4 patients with negative groin cultures had negative chest and abdominal cultures.

Conclusions: About half of asymptomatic rectal carriers of C. difficile had positive groin cultures, and these individuals had a greater burden of C. difficile in stool and more frequent contamination of commonly examined skin sites. Groin cultures may be an acceptable method to identify a subset of asymptomatic carriers of C. difficile with increased potential to transmit spores.