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.