Appendectomy and C. difficile Infection J Clin Med Res • 2011;4(1):17-19 pendectomy among patients with non-CDAD may reflect difficulties in re-colonizing the lower gut and is consistent with the idea that the appendix plays an important role in re- establishing normal bacterial colonization. It is also worth noting that the only a small minority of colitis patients develop C. difficile infections. Thus the ben- efits of gut re-colonization and prevention of colitis occur much more frequently than pathogenic C. difficile infections. This is likely to be important from an evolutionary perspec- tive where the substantial infirmity that arises from appen- dicitis is balanced by benefits from an intact appendix and overall increased survival [2]. With this in mind, it may be possible to implement treatments for acute appendicitis, such as selective antibiotic therapy, that reduce the morbidity and mortality of appendicitis, while preserving the appendiceal microbial reservoir [9, 10]. Limitations Our choice of case-control methodology makes it impossible for us to demonstrate causality. Our observed associations may not be due the presence or absence of an appendix, but may reflect biological processes that alter both the risk of developing appendicitis, and risk of developing CDAD. Demonstrating causality will be difficult, as a definitive ran- domized controlled trial of appendectomy is unlikely to be conducted in the foreseeable future. Our methodology also makes it impossible for us to determine the prevalence of C. difficile among our popu- lations. This information may improve our understanding of the relationship between C. difficile and appendectomy, but was not essential to the primary purpose of this inves- tigation. We are also limited in our ability to examine how infection and appendectomy rates vary as a consequence of important variables such as prior antibiotics use, history of prior bowel dysfunction, age, duration of symptoms, and others. Our results also likely overestimate appendectomy rates among our case population. This is a reflection of the imper- fect specificity of the toxin A & B EIA test and the potential for the false positive rate to attain a magnitude similar to the prevalence of CDAD. The false positive cases are likely to have appendectomy rates similar to the true negatives (31.4% in this case), and increase the observed appendectomy rates among our case population. Eliminating this source of bias would likely lead to an even stronger association between the CDAD and the presence of an intact appendix. Conclusions The rate of prior appendectomy was lower among our pa- tients who test positive by EIA for C. difficile toxin as com- pared with patients who test negative. At our institution, more than 80% of C. difficile infections occurred in patients who had an intact appendix. Acknowledgement William R. Mower had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. References 1. Randal Bollinger R, Barbas AS, Bush EL, Lin SS, Park- er W. Biofilms in the large bowel suggest an apparent function of the human vermiform appendix. J Theor Biol. 2007;249(4):826-831. 2. Ansaloni L, Catena F, Pinna AD. What is the function of the human vermiform appendix?. Evolution-based sur- gery: a new perspective in the Darwinian year 2009. Eur Surg Res. 2009;43(2):67-71. 3. Bartlett JG, Gerding DN. Clinical recognition and diag- nosis of Clostridium difficile infection. Clin Infect Dis. 2008;46 Suppl 1:S12-18. 4. Kim J, Smathers SA, Prasad P, Leckerman KH, Coffin S, Zaoutis T. Epidemiological features of Clostridium dif- ficile-associated disease among inpatients at children’s hospitals in the United States, 2001-2006. Pediatrics. 2008;122(6):1266-1270. 5. Barbut F, Petit JC. Epidemiology of Clostridium dif- ficile-associated infections. Clin Microbiol Infect. 2001;7(8):405-410. 6. Spencer RC. Clinical impact and associated costs of Clostridium difficile-associated disease. J Antimicrob Chemother. 1998;41 Suppl C:5-12. 7. Dubberke ER, Gerding DN, Classen D, Arias KM, Pod- gorny K, Anderson DJ, Burstin H, et al. Strategies to prevent clostridium difficile infections in acute care hos- pitals. Infect Control Hosp Epidemiol. 2008;29 Suppl 1:S81-92. 8. http://statpages.org/ctab2x2.html accessed 3/02/2010. 9. Hansson J, Korner U, Khorram-Manesh A, Solberg A, Lundholm K. Randomized clinical trial of antibiotic therapy versus appendicectomy as primary treatment of acute appendicitis in unselected patients. Br J Surg. 2009;96(5):473-481. 10. Styrud J, Eriksson S, Nilsson I, Ahlberg G, Haapani- emi S, Neovius G, Rex L, et al. Appendectomy versus antibiotic treatment in acute appendicitis. a prospective multicenter randomized controlled trial. World J Surg. 2006;30(6):1033-1037. Articles © The authors | Journal compilation © J Clin Med Res and Elmer Press™ | www.jocmr.org 19