Lactobacillus rhamnosus sepsis associated with probiotic therapy in an extremely preterm infant: Pathogenesis and a review for clinicians.

BACKGROUND Necrotizing enterocolitis (NEC) is one of the most serious complications in preterm infants. Probiotics have been used to prevent NEC. Safety is a major concern for this practice. METHODS We reported a female preterm infant who received oral Lactobacillus rhamnosus GG but developed sepsis 12 days after the treatment. Cultures of blood and the catheter tip yielded L. rhamnosus. Next-generation sequencing was performed to analyze isolates from blood, stool, catheter, and product capsules. We also determined the capacities of these isolates to form biofilms. A literature review was performed. RESULTS The patient was treated with ampicillin and piperacillin/tazobactam, and she subsequently recovered without complications. The analysis of genome sequences indicated that all the isolates belonged to the clone of L. rhamnosus GG (ATCC 53103), suggesting that sepsis was a catheter-related infection caused by the oral probiotic. L. rhamnosus GG (ATCC 53103) and the probiotic strain tested formed biofilms under all growth conditions. Isolates from the blood and catheter tip also formed biofilms, but the stool isolate did not. The capacity of intrinsic biofilm formation in L. rhamnosus GG depended on environmental factors and the type of culture medium. Literature review of L. rhamnosus GG sepsis in preterm and young infants found that nearly 60% of the patients had a suspected or confirmed infected catheter. CONCLUSION The study showed that the capacity of L. rhamnosus GG to form biofilms, especially in the presence of glucose, is a critical factor leading to the probiotic-related sepsis in preterm infants.