Short-term and medium-term clinical outcomes of quinolone-resistant Campylobacter infection.

BACKGROUND Campylobacter species is a leading cause of bacterial gastroenteritis worldwide. Quinolone resistance has emerged as an increasing problem among persons with Campylobacter infection over the past decade, but the clinical consequences are unclear. METHODS A case-comparison study of patients infected with ciprofloxacin-resistant or ciprofloxacin-susceptible Campylobacter species was conducted in Wales during the period 2003-2004. Campylobacter isolates were classified as resistant or susceptible to ciprofloxacin on the basis of standardized disk diffusion methods. Participants were interviewed by telephone at the time of illness, 3 months later, and 6 months later to compare disease severity, duration of illness, and medium-term clinical outcomes. RESULTS There was no difference between 145 persons with ciprofloxacin-resistant infection and 411 with ciprofloxacin-susceptible infection with regard to the severity or duration of acute illness. Mean duration of diarrhea was similar in patients with ciprofloxacin-resistant versus ciprofloxacin-susceptible infection (8.2 vs. 8.6 days; P = .57) and did not alter significantly after adjustment for potential covariates, including age, underlying disease, foreign travel, use of antidiarrheal medication, and use of antimicrobials in a multiple linear regression model. There was no difference between case patients and comparison patients in the frequency of reported symptoms or in general practitioner consultation rates at either the 3-month or the 6-month follow-up interview. CONCLUSIONS In this study, there was no evidence of more-severe or prolonged illness in participants with quinolone-resistant Campylobacter infection, nor was there evidence of any adverse medium-term consequences. This suggests that the clinical significance of quinolone resistance in Campylobacter infection may have been overestimated.