Campylobacter spp Bloodstream Infections in Immunocompetent vs Immunodeficient Patients: A Multinational Cohort Study (2009–2024)

Background Campylobacter spp bloodstream infections (BSIs) are an emerging clinical challenge, yet information on their clinical features remains limited. We aimed to evaluate their differential clinical characteristics and outcomes in immunocompetent (IC) and immunodeficient (ID) patients. Methods A multicenter, multinational, retrospective cohort study of consecutive Campylobacter spp BSIs between 2009 and 2024 was carried out. Demographics, Charlson comorbidity index, types of immunodeficiencies, clinical characteristics, and antimicrobial susceptibility were analyzed. The primary outcomes were relapse or reinfection and death (all-cause mortality outcome). Results A total of 261 episodes were included, 89 (34.1%) in IC and 172 (65.9%) in ID patients. Among the 172 ID patients, 104 (60.5%) and 68 (39.5%) had humoral or nonhumoral immunodeficiency (primary or secondary), and 42 (24.4%) had primary immunodeficiencies (PIDs). Patients with humoral immunodeficiency (humoral-ID patients) were younger (median age, 40 years [interquartile range, 23–66 years]), had lower Charlson comorbidity indexes (2 [1–5]), and had a higher frequency of previous Campylobacter spp infection. Resistance rates to fluoroquinolones (75%) and macrolides (14.5%) were high. BSI relapse or reinfection occurred in 21 (8.0%) patients, mostly humoral-ID patients (n = 19 [18.3%]), 11 (57.9%) of whom had PID. Death occurred with 30 days (all-cause mortality outcome) in 26 patients (9.9%) across the entire cohort; the 30-day mortality rate was lower in humoral-ID (n = 5 [4.8%]) than in IC (n = 12 [13.5%]; P = .05) patients. Conclusions Humoral-ID patients and those with Campylobacter spp BSI were younger and had fewer comorbid conditions, and Campylobacter coli was the most frequent species. Relapse or reinfection was common in humoral-ID patients, particularly those with PID. The antimicrobial resistance in C coli and Campylobacter jejuni represents a clinical concern.