Factors Predicting Blood Culture Positivity in Children With Enteric Fever

Abstract

Background Blood culture, despite low sensitivity, is the gold standard for enteric fever diagnosis. Understanding predictors of blood culture positivity may help design strategies to optimize enteric fever diagnosis. Methods A cohort of 6760 children aged 0.5–15 years was followed for 3 years for enteric fever with blood cultures in an automated system, for fevers >3 days. Factors affecting test positivity in fevers and participant-level predictors for culture refusals were analyzed using regression models. Results Overall, 6097 suspected typhoid/paratyphoid fever (STF) episodes were reported, of which 5703 (93.5%) STFs had sampling for blood cultures, with 394 (6.5%) refusals. Salmonella enterica serovar Typhi/Paratyphi positivity was culture-confirmed in 3.8% (218/5703) of STF episodes. Older children (odds ratio [OR], 1.96 [95% CI, 1.39–2.77]), larger blood volume inoculated (OR, 2.82 [95% CI, 1.71–4.66]), higher temperatures during fever (OR, 3.77 [95% CI, 2.89–4.91]), and fevers diagnosed as suspected typhoid or acute undifferentiated fever (OR, 6.06 [95% CI, 3.11–11.78]) had a higher probability of culture positivity. Antibiotics before culture did not decrease culture positivity. Blood culture refusals were higher for children from wealthier households or with milder illness. Conclusions Performing blood cultures in older children with fever, especially those fevers with toxic presentation and increasing blood volume for inoculation are strategies to improve enteric fever detection in surveillance settings.

Retrospective Review of Blood Culture-Confirmed Cases of Enteric Fever in Navi Mumbai, India: 2014–2018

“…This retrospective review of the results of blood cultures from just one of Navi Mumbai’s diagnostic laboratories is comparable to more complete data from throughout South Asia 10 , 17 and indicates a medium typhoid burden in Navi Mumbai at a minimum. Our data support further work to investigate mechanisms by which Navi Mumbai’s enteric fever case positivity rate is highest during the dry season.…”

“…The overall average S. Typhi and S. Paratyphi A positivity rate for blood cultures performed at Joshi Laboratory between 2014 and 2018 was 3.1%, which is similar to the rate reported from Vellore, India (3.8%) over a comparable time period. 10 A retrospective review from the Surveillance for Enteric Fever in Asia Project portrayed a much lower enteric fever blood culture positivity rate (0.53%) from five hospitals across India. 11 The enteric fever blood culture positivity rate at Joshi Laboratory trended up over the course of the study period, whereas other South Asian data suggest decreased rates from 2000 to 2015 in India, which has been attributed to improved economic factors, sanitation, and hygiene.…”

Retrospective Review of Blood Culture-Confirmed Cases of Enteric Fever in Navi Mumbai, India: 2014–2018

“…That said, blood cultures were collected at the primary provider's discretion, which may result in missed non-severe or atypical cases and this underdiagnosis is compounded by the low sensitivity of optimally collected blood cultures (59%), made even lower with antibiotic use. 9 This retrospective review of the results of blood cultures from just one of Navi Mumbai's diagnostic laboratories is comparable to more complete data from throughout South Asia 10,17 and indicates a medium typhoid burden in Navi Mumbai at a minimum. Our data support further work to investigate mechanisms by which Navi Mumbai's enteric fever case positivity rate is highest during the dry season.…”

“…The overall average S. Typhi and S. Paratyphi positivity rate for blood cultures performed at Joshi Lab between 2014-2018 was 3.1%, which is similar to the rate reported from Vellore, India (3.8%) over a comparable time period. 10 A retrospective review from the Surveillance for Enteric Fever in Asia Project portrayed a much lower enteric fever blood culture positivity rate (0.53%) from 5 hospitals across India. 11 The enteric fever blood culture positivity rate at Joshi Lab trended up over the course of the study period, while other South Asian data suggest decreased rates from 2000-2015 in India, which has been attributed to improved economic factors, sanitation, and hygiene.…”

Burden of Typhoid and Paratyphoid Fever in India

“…Prior analyses from this study on the relationship of antibiotics and culture positivity did not yield a relationship. 30 …”