P717 C.difficile colonisation and infection rates are now low in IBD - a matched cohort study
N. Joshi*1, R. Crowson1, D. Ball2, D. Rampton1
1Queen Mary, University of London, Blizard Institute, Centre for Digestive Diseases, London, United Kingdom, 2Barts Health NHS Trust, Medical Microbiology, London, United Kingdom
Several studies in the last 10 years have reported higher rates of C.difficile colonisation (CDC) and C.difficile infection (CDI) in patients with IBD than in those without [1,2]. We have now reevaluated the incidence of CDC and CDI in diarrhoeal inpatients with IBD and a matched contemporaneous cohort of diarrhoeal patients without IBD.
All 2284 in-patient stool samples tested for C.difficile at Barts Health Trust in a 12-month period ending April 2013 were recorded in our microbiology database. A 2-step ELISA algorithm for C.difficile testing was used: the first was a test for CDC (presence of glutamate dehydrogenase, a C.difficile-specific enzyme); if present, a second step was performed to look for CDI (presence of toxin B). If more than 1 sample was sent during an admission, only the first was included in analysis. IBD patients from whom the samples were obtained were identified using electronic patient records. They were then matched with non-IBD controls, taken from the same cohort, for age and for the number of days they had been admitted when the sample was sent.
170/2284 (7%) samples were from patients with IBD. The IBD and non-IBD groups were well-matched: age - 34.0 (3.8-87.6) and 34.2 (3.4-88) years [median (range)] (R2 0.99), and days admitted until sample sent - 2.2 (0-31) and 2.5 (0-31) (R2 0.93). Nine/170 (5%) IBD patients had CDC vs 28/170 (16%) controls (p=0.0017). One/9 (11%) CDC-positive IBD patients had CDI, compared with 6/28 (21%) of the CDC-positive controls (p=ns). Current antibiotic exposure was lower in the IBD group (28%) than in the controls (57%) (p=0.0006). There were no significant differences between the IBD and control groups in 3-month mortality (1%, 5%), in 3-month re-admission rates (25%, 25%) or antibiotic exposure in the previous 3 months (11%, 20%).
CDC is less common in diarrhoeal inpatients with IBD than in matched controls without IBD. The higher incidence of CDC in the control patients may be due to increased antibiotic exposure in this group. C.difficile infection is now rare in IBD, being found in <1% of our IBD patients presenting with diarrhoea.
 Clayton EM et al, (2009), The vexed relationship between Clostridium difficile and inflammatory bowel disease: an assessment of carriage in an outpatient setting among patients in remission., Am J Gastroenterol , 104:1162-9
 Bossuyt P et al, (2009), ncreasing incidence of Clostridium difficile-associated diarrhea in inflammatory bowel disease., J Crohns Colitis , 1:4-7