Gastrointestinal colonization of extended-spectrum beta-lactamase-producing bacteria among children below five years of age hospitalized with fever in Dar es Salaam, Tanzania

Objectives: Gastrointestinal colonization of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-PE) is of concern because prior colonization increases risk for subsequent infections. To date, the link between ESBL-PE faecal carriage and the risk of subsequent ESBL-PE infection has not been well established, and information on carriage of such pathogens among children with invasive infections such as bloodstream infections (BSI) remains to be explored worldwide. 

Methods: This cross-sectional study was conducted among children under the age of 5 years admitted for febrile illness in Dar es Salaam, Tanzania, between March 2017 and July 2018. We used rectal swabs to screen for ESBL-PE using selective media, ChromID ESBL. Bacterial isolates were identified by MALDI-TOF. Blood cultures were drawn from all children. Antimicrobial susceptibility testing was done using a disk diffusion method. ESBL alleles were identified by real-time PCR and sequencing. 

Results: The overall prevalence of ESBL-PE carriage was 56% (112/200) and was highest among children 4 to 6 months old (17/21, 81%) (P = 0.05). Children with BSI had high ESBL-PE carriage (78.4%) compared to those without BSI (53.1%) (P = 0.02; aOR 3.4, 95% confidence interval 1.20–9.58). The most common isolate was E. coli (64/112, 45%). Sixteen pairs of ESBL-PE isolates (from the gut and from blood) had a similar antimicrobial susceptibility profile. We detected bla_CTX-M gene in 97% of all phenotypically detected ESBL-PE; among those, bla_CTX-M-15 was dominant (99%). 

Conclusion: We report a high prevalence of ESBL-PE faecal carriage among children with BSI in Tanzania. Colonization of ESBL-PE was a risk factor for ESBL-BSI.