Toxin-Producing Klebsiella oxytoca in Healthy Infants: Commensal or Pathobiont?. Issue 1 (January 2022)

• Record Type: Journal Article
• Authors: Greimel, Theresa M.; Stampfer, Laura; Leitner, Eva; Kienesberger, Sabine; Zechner, Ellen L.; Bozic, Michael; Wagner, Gabriel E.; Unterhauser, Katrin; Kitsera, Maksym; Hauer, Almuthe C.; Gorkiewicz, Gregor; Wurm, Philipp; Valitutti, Francesco; Högenauer, Christoph; Hoffmann, Karl Martin
• Is Part Of: Journal of pediatric gastroenterology and nutrition. Volume 74:Issue 1(2022)
• Publication Date: 2022-01
• Subjects: bacteria -- cytotoxins -- infants -- Klebsiella oxytoca -- microbiome -- pathobiont -- pediatrics; Children -- Nutrition -- Periodicals; Pediatric gastroenterology -- Periodicals; Infants -- Nutrition -- Periodicals; Nutrition disorders in children -- Periodicals; Child Nutrition -- Periodicals; Digestive System -- growth & development -- Periodicals; Gastrointestinal Diseases -- Periodicals; Infant Nutrition -- Periodicals; Nutrition Disorders -- Periodicals; Child; 618.923
• DOI: 10.1097/MPG.0000000000003299
• Languages: English
• ISSNs: 0277-2116

Abstract

ABSTRACT: Objectives: Klebsiella oxytoca is a gastrointestinal pathobiont with the potential to produce the toxins tilivalline and tilimycin, which cause antibiotic-associated hemorrhagic colitis. Overgrowth of toxigenic K oxytoca has recently been implicated in necrotizing enterocolitis. K oxytoca colonizes 2–9% of healthy adults, however, there is no systematic data on colonization in healthy children. We investigated K oxytoca colonization and its toxigenic properties in healthy infants. Methods: We sampled stool of healthy infants and determined K oxytoca colonization using stool culture and PCR ( pehX ). Toxin in stool was measured with HPLC/high-resolution mass spectrometry. K oxytoca isolates were typed using multi-locus sequence typing (MLST) and K oxytoca toxin PCR ( npsA/B ). Cytotoxin production of isolates was analyzed by MTT assay. Results: K oxytoca was detected in 30 of 61 infants (49%) using stool culture and in 45 of 61 (73%) using PCR ( pehX ). Toxin marker PCR ( npsA/B ) was positive in 66% of stool samples positive for K oxytoca PCR. Stool toxin levels were too low for quantitation but traces of tilivalline were detected. Contrarily, 49% of K oxytoca isolates demonstrated toxicity in the MTT assay. MLST revealed 36 distinct sequence types affiliated with all known K oxytoca sequence type clusters (A, B1 and B2). Conclusions: More than 70% of healthy infants were colonized with K oxytoca . Toxin quantities in stool of colonized healthy infants were below detection level, yet half of the isolates produced toxin in vitro demonstrating their pathobiont potential. The high occurrence of toxigenic K oxytoca in healthy infants has to be considered for future disease association studies.