A Common Polymorphism in the Interleukin‐8 Gene Promoter Is Associated with an Increased Risk for RecurrentClostridium difficileInfection

Abstract

Neutrophil recruitment coordinated by intestinal interleukin (IL)-8 secretion is a key component in the pathogenesis of Clostridium difficile infection (CDI). We hypothesized that a common single-nucleotide polymorphism (SNP) in the -251 region of the IL-8 gene promoter may be predictive of recurrent CDI. This was a prospective cohort study of hospitalized adult patients with CDI who were admitted to a large, university-affiliated medical center from 2007 through 2008. Patients were monitored for 3 months after diagnosis of CDI and assessed for recurrent CDI (defined as a return of diarrhea that required treatment after initial symptom resolution). DNA was isolated from blood samples, and genetic sequencing was performed using polymerase chain reaction and pyrosequencing. The association between IL-8 genotype and recurrent CDI was assessed using univariate and multivariate statistics. Ninety-six patients with a mean (± standard deviation) age of 61 ± 16 years (54% of whom were female and 63% of whom were white) were identified. The overall incidence of recurrent CDI was 24%. IL-8 allele frequency was similar to previously reported findings (for A/A, 27%; for A/T, 53%; and for T/T, 20%). The incidence of recurrent CDI was 38% in patients with the A/A allele and 19% in all other patients (relative risk, 2.1; 95% confidence interval, 1.04-4.13) (P = .043). This study indicates that a common SNP in the IL-8 gene promoter is an independent predictor of recurrent CDI. Our results could offer risk stratification for patients at high risk for recurrent CDI.