The clinical characteristics and outcomes of Campylobacter spp. bloodstream infection: A systematic review and meta-analysis

Campylobacter spp. bloodstream infection (BSI) poses a significant challenge in clinical practice, particularly among certain populations such as immunocompromised individuals, mainly humoral immunodeficiencies. Objectives are to provide a comprehensive assessment and summarise the current evidence of the characteristics, clinical management and outcomes associated with Campylobacter spp. BSI. We searched PubMed, EMBASE and Cochrane for original research articles and case series/reports published in English or Spanish between January-1990 and October-2024 including patients with Campylobacter spp. BSI. Outcomes included antimicrobial treatment received, treatment resistance, all-cause mortality and relapses. Case reports/series and primary research articles were summarised separately. Primary research studies were pooled in a random-effect meta-analysis to estimate mortality and relapse, overall and by subgroup species. Heterogeneity was assessed using the I2 statistic. Meta-regression for the relationship of outcomes and variables of interest was performed where data allowed. The quality of the studies was assessed using the NIH Quality Assessment Tool for Case Series Studies. From the 1441 articles retrieved from our search, 32 primary research articles (2138 participants) and 196 small case series or single case reports (212 cases) were included. Within the 32 retrospective studies, 1259 (58.9%) patients had some immunocompromise. The most frequent species was Campylobacter jejuni (n = 928, 43.4%), of which 47.8% were resistant to quinolones. The meta-analysis showed a mortality rate of 7.2% (95%CI 4.6%–10.2%; I2 70.7%); subgroup meta-analysis: C. jejuni: 3.8%, C. fetus: 10.4%, C. coli: 10.1%. Meta-regression suggested a direct association between the proportion of C. fetus BSI episodes included in the studies and mortality. The pooled relapse rate was 2.3%, and meta-regression analysis indicated that C. jejuni infection was associated with a lower risk of relapse compared with C. coli and C. fetus (p = 0.0002). Our systematic review and meta-analysis suggest high antimicrobial resistance rates, mortality and risk of relapse, with some differences by Campylobacter species.