Antibiotic Use Prior to Hospital Presentation Among Individuals With Suspected Enteric Fever in Nepal, Bangladesh, and Pakistan

Abstract

Background: Antibiotic use prior to seeking care at a hospital may reduce the sensitivity of blood culture for enteric fever, with implications for both clinical care and surveillance. The Surveillance for Enteric Fever in Asia Project (SEAP) is a prospective study of enteric fever incidence in Nepal, Bangladesh, and Pakistan. Nested within SEAP, we evaluated the accuracy of self-reported antibiotic use and investigated the association between antibiotic use and blood culture positivity.

Methods: Between November 2016 and April 2019, we collected urine samples among a subset of SEAP participants to test for antibiotic use prior to the hospital visit using an antibacterial activity assay. All participants were asked about recent antibiotic use and had a blood culture performed. We used mixed-effect logit models to evaluate the effect of antimicrobial use on blood culture positivity, adjusted for markers of disease severity.

Results: We enrolled 2939 patients with suspected enteric fever. Antibiotics were detected in 39% (1145/2939) of urine samples. The correlation between measured and reported antibiotic use was modest (κ = 0.72). After adjusting for disease severity, patients with antibiotics in their urine were slightly more likely to be blood culture positive for enteric fever; however, the effect was not statistically significant (prevalence ratio, 1.22 [95% confidence interval, .99-1.50]).

Conclusions: The reliability of self-reported prior antibiotic use was modest among individuals presenting with fever to tertiary hospitals. While antibiotics are likely to reduce the sensitivity of blood culture, our findings indicate that there is still considerable value in performing blood culture for individuals reporting antibiotic use.

Keywords: antimicrobial resistance; blood culture; enteric fever; typhoid.

Figure 1.

Differences between antibiotic detection and report across study country and age strata, Surveillance for Enteric Fever in Asia Project—Bangladesh, Nepal, and Pakistan, 2016–2019. Differences in the percentage of patients reporting antibiotic use and patients with antibiotics detected in the urine by country and age category among 2939 outpatients with ≥3 consecutive days of fever in Bangladesh, Nepal, and Pakistan. Vertical line in the middle of each bar depicts the 95% confidence interval around the percentage.

Figure 2.

Age and facility care-seeking for current illness by country, Surveillance for Enteric Fever in Asia Project—Bangladesh, Nepal, and Pakistan, 2016–2019. Percentage of patients seeking care at a clinic, hospital, pharmacy, physician, or traditional healer prior to presenting to the study site among 2939 outpatients with ≥3 consecutive days of fever in Bangladesh, Nepal, and Pakistan.