Bacterial Indole as a Multifunctional Regulator of Klebsiella oxytoca Complex Enterotoxicity

Abstract

The human gut harbors a complex community of microbes, including several species and strains that could be commensals or pathogens depending on context. The specific environmental conditions under which a resident microbe changes its relationship with a host and adopts pathogenic behaviors, in many cases, remain poorly understood.

Molecular Confirmation of an Indole-Negative <i>Klebsiella oxytoca</i> Isolated from a Patient with Cystitis

“…A report indicates that diseases caused by K. pneumoniae or K. oxytoca do not strictly coincide (10), but there have been no previous reports that indole-positive K oxytoca is more virulent. In a recent study on K. oxytoca and Klebsiella grimontii, the authors reported that bacterial indole functions as a regulator that inhibits the synthesis of bacterial toxins and mitigates tissue cytotoxicity (11). In the present study, the pathogenic changes in K. oxytoca that were indole-negative were unknown and may be clarified in the future through infection experiments using animals.…”

An adapted method for Cas9-mediated editing reveals the species-specific role of β-glucoside utilization driving competition betweenKlebsiellaspecies

“…Following gene editing, both plasmids could be easily cured, creating markerless strains for downstream analyses. Given the increasing interest in characterizing competitive interactions between gut bacteria and Klebsiella species in particular 5,6,13,39,40 , we anticipate that our tool will contribute to mechanistic studies of microbiome communities.…”

Complete Genome Sequence of Klebsiella oxytoca Strain AHC-6, Isolated from a Patient during Acute Antibiotic-Associated Hemorrhagic Colitis

“…Multilocus sequence type 1 was assigned ( 14 ) (isolate 34) and cytotoxicity towards cultured human cells was assessed ( 15 ) (see strain 04/1O). Murine infection models confirmed in vivo toxin production by AHC-6 ( 16 , 17 ), identified the molecular targets of tilimycin and tilivalline, providing a mechanistic link to epithelial cell damage ( 7 , 16 ), and showed that the genotoxicity induced by tilimycin generates DNA lesions in enterocytes ( 16 ) and decreases microbial diversity while promoting the emergence of antibiotic resistance in the gut microbiome ( 18 ).…”