Bacteraemia, antimicrobial susceptibility and treatment among Campylobacter-associated hospitalisations in the Australian Capital Territory: a review

Background: Campylobacter spp. cause mostly self-limiting enterocolitis, although a significant proportion of cases require hospitalisation highlighting potential for severe disease. Among people admitted, blood culture specimens are frequently collected and antibiotic treatment is initiated. We sought to understand clinical and host factors associated with bacteraemia, antibiotic treatment and isolate non-susceptibility among Campylobacter-associated hospitalisations. Methods: Using linked hospital microbiology and administrative data we identified and reviewed Campylobacter-associated hospitalisations between 2004 and 2013. We calculated population-level incidence for Campylobacter bacteraemia and used logistic regression to examine factors associated with bacteraemia, antibiotic treatment and isolate non-susceptibility among Campylobacter-associated hospitalisations. Results: Among 685 Campylobacter-associated hospitalisations, we identified 25 admissions for bacteraemia, an estimated incidence of 0.71 cases per 100,000 population per year. Around half of hospitalisations (333/685) had blood culturing performed. Factors associated with bacteraemia included underlying liver disease (aOR 48.89, 95% CI 7.03–340.22, p < 0.001), Haematology unit admission (aOR 14.67, 95% CI 2.99–72.07, p = 0.001) and age 70–79 years (aOR 4.93, 95% CI 1.57–15.49). Approximately one-third (219/685) of admissions received antibiotics with treatment rates increasing significantly over time (p < 0.05). Factors associated with antibiotic treatment included Gastroenterology unit admission (aOR 3.75, 95% CI 1.95–7.20, p < 0.001), having blood cultures taken (aOR 2.76, 95% CI 1.79–4.26, p < 0.001) and age 40–49 years (aOR 2.34, 95% CI 1.14–4.79, p = 0.02). Non-susceptibility of isolates to standard antimicrobials increased significantly over time (p = 0.01) and was associated with overseas travel (aOR 11.80 95% CI 3.18–43.83, p < 0.001) and negatively associated with tachycardia (aOR 0.48, 95%CI 0.26–0.88, p = 0.02), suggesting a healthy traveller effect. Conclusions: Campylobacter infections result in considerable hospital burden. Among those admitted to hospital, an interplay of factors involving clinical presentation, presence of underlying comorbidities, complications and increasing age influence how a case is investigated and managed.