Bactec automated culture system

Whole blood was collected before treatment and incubated for up to 5 days using the BACTEC automated culture system (Becton Dickinson, Franklin Lakes, NJ, USA), or the BacTAlert 3D automated blood culture system (BioMérieux, Marcy-l’Étoile, France). Positive samples were subcultured onto MacConkey agar, chocolate agar, or sheep blood agar (or a combination of these), and species were confirmed using biochemical testing and O and H antisera (MAST ASSURE, Mast Group, Liverpool, UK), if available.¹⁹ (link) Isolates obtained from laboratory network sites were confirmed at the study hospital laboratories using the same methods. All hospital laboratories were enrolled in WHO or College of American Pathologists external quality assurance programmes.
To estimate the proportion of individuals with a febrile illness in the catchment area compatible with enteric fever who sought care at the study facilities, interviewers administered a standard questionnaire to all households within randomly selected clusters of the defined catchment areas. The design and implementation of the health-care utilisation survey, including sample size calculations, are described elsewhere.20 (link), 21 (link)
We defined disease severity by hospitalisation. Hospitalisation at the enrolment visit was documented in the medical charts, and hospitalisation during the 6-week follow-up period was patient-reported.

A sample of peripheral venous blood was collected from each study participant in either a BD BACTEC (TM) or BD BACTEC PEDS Plus (TM) aerobic bottle and incubated for up to 5 days, using the BACTEC automated culture system (BACTEC; Becton Dickinson, Baltimore, MD). Indicator-positive samples were then subcultured onto MacConkey agar plates and nonselective media (sheep blood agar). Species were confirmed using biochemical testing and O and H antisera (BD Laboratories), if available.
Research assistants reviewed hospital records and entered information on physical exam findings and additional laboratory test results into a custom-built, electronic data-capture system. Complete blood count results were only available from participants for whom the test was indicated and performed. Temperature was assessed on arrival to the outpatient department or upon admission to the inpatient department. Fever start date, days of being unable to conduct normal activity, cough, diarrhea, constipation, abdominal pain, vomiting, nausea, and headache were all measured using self-r or caregiver-report and were collected directly from the patient or guardian at the time of enrollment into SEAP. We also recorded the clinician’s assessment of whether the patient had enteric fever, which was made before blood culture results were available.