Bacteraemia caused by Lactobacillus rhamnosus given as a probiotic in a patient with a central venous catheter: a WGS case report

INTRODUCTION: Lactobacilli, especially Lactobacillus (L.) rhamnosus, are common and well-documented components of commercial probiotics [1]. Whole genome sequencing (WGS) is often used to compare bacterial genomes and their relatedness. In outbreak situations, it is used to investigate the transmission of pathogenic bacteria. WGS has also been used to determine safety in probiotics, by looking at potential virulence factors and resistance genes. CASE PRESENTATION: This case report describes a 56-year old multi-traumatised, immunocompetent woman who was given L. rhamnosus GG as a probiotic, and later developed a blood stream infection with L. rhamnosus GG. The patient was fed by a nasogastric tube, and she also had a central venous catheter for parenteral feeding. When the patient developed diarrhoea after long-term hospitalisation, she was given L. rhamnosus GG, as a probiotic, which was standard care on the ward where she was hospitalised. In this case report we describe the use of WGS to demonstrate that a patient fed with L. rhamnosus GG as a probiotic, developed a blood stream infection with the same strain. CONCLUSION: In this case WGS was applied to show the relatedness of a probiotic and a pathogenic strain of L. rhamnosus GG. This case emphasises the need for caution when administering probiotics to patients with indwelling catheters. The patient was immunocompetent and she cleared the infection without the need for antibiotics.