Improved diagnosis of antibiotic-associated haemorrhagic colitis (AAHC) in faecal specimens by a new qualitative real-time PCR assay detecting relevant toxin genes of Klebsiella oxytoca sensu lato

Leitner, Eva; Bozic, Michael; Kienesberger, Sabine; Ćosić, Amar; Landt, Olfert; Högenauer, Christoph; Kessler, Harald H.

doi:10.1016/j.cmi.2021.09.017

Cited by 4 publications

(2 citation statements)

References 33 publications

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“…with diseases affecting preterm infants is complex and warrants further study. Adoption of the real-time PCR assay for npsAB genes [ 76 ], with a sensitivity of 15 cfu/ml of sample, for the detection of potential cytotoxin - producing bacteria in the faeces of preterm infants would allow us to better define the relationship between these pathogens and the presentation of NEC in this cohort. In addition, it is clear that refined molecular-based identification [whole genome (15), shotgun metagenomic [ 12 ] or rpoB gene [ 77 ] sequencing] should be adopted to accurately identify members of the K. oxytoca complex in the gut microbiota of preterm infants and to correctly identify clinically relevant isolates.…”

Section: Virulence Of Klebsiella Spp and Cytotoxicitymentioning

confidence: 99%

The role of Klebsiella populations in preterm infants

McCartney

Hoyles

2023

Biochemical Society Transactions

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The preterm infant microbiota is dominated by Enterobacteriaceae (Escherichia, Klebsiella or Enterobacter spp.), Enterococcus and Staphylococcus spp. Recent work has demonstrated the development of this microbiota is predictable and driven by simple microbe–microbe interactions. Because of their systemic immaturity, including an underdeveloped immune system, preterm infants are susceptible to a range of infections. Numerous retrospective studies have examined the association of the preterm gut microbiota with diseases such as necrotizing enterocolitis (NEC), early-onset sepsis and late-onset sepsis. To date, no single bacterium has been associated with infection in these infants, but a Klebsiella/Enterococcus-dominated faecal microbiota is associated with an increased risk of developing NEC. Staphylococci aid and enterococci inhibit establishment/maintenance of gastrointestinal Klebsiella populations in preterm infants, though the mechanisms underlying these interactions are poorly understood. Klebsiella spp. recovered from healthy and sick preterm infants display similar antimicrobial resistance and virulence profiles, giving no clues as to why some infants develop potentially life-threatening diseases while others do not. The identification of cytotoxin-producing Klebsiella oxytoca sensu lato in the gut microbiota of some preterm infants has led to the suggestion that these bacteria may contribute to NEC in a subset of neonates. This mini review highlights current knowledge on Klebsiella spp. contributing to the preterm gut microbiota and provides insights into areas of research that warrant further attention.

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Section: Virulence Of Klebsiella Spp and Cytotoxicitymentioning

confidence: 99%

The role of Klebsiella populations in preterm infants

McCartney

Hoyles

2023

Biochemical Society Transactions

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“…Normally, the host insect turns on some metabolic pathways to resist EPN infestation, while EPNs release toxic molecules to cause metabolic disorders of the host ( Agus et al, 2018 ). For example, excessive accumulation of reactive oxygen species and Trp metabolites will cause disease and even death ( Zhang et al, 2019 ; Leitner et al, 2022 ). However, biomarkers that cause insect death and impair insect immunity are produced by bacteria, such as fabclavine and some peptides ( Elias et al, 2020 ; Wenski et al, 2020 ; Kenney et al, 2021 ).…”

Section: Introductionmentioning

confidence: 99%

Metabonomics reveals that entomopathogenic nematodes mediate tryptophan metabolites that kill host insects

Zhang

Wang²,

Zhao³

2022

Front. Microbiol.

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The entomopathogenic nematode (EPN) Steinernema feltiae, which carries the symbiotic bacterium Xenorhabdus bovienii in its gut, is an important biocontrol agent. This EPN could produce a suite of complex metabolites and toxin proteins and lead to the death of host insects within 24–48 h. However, few studies have been performed on the key biomarkers released by EPNs to kill host insects. The objective of this study was to examine what substances produced by EPNs cause the death of host insects. We found that all densities of nematode suspensions exhibited insecticidal activities after hemocoelic injection into Galleria mellonella larvae. EPN infection 9 h later led to immunosuppression by activating insect esterase activity, but eventually, the host insect darkened and died. Before insect immunity was activated, we applied a high-resolution mass spectrometry-based metabolomics approach to determine the hemolymph of the wax moth G. mellonella infected by EPNs. The results indicated that the tryptophan (Trp) pathway of G. mellonella was significantly activated, and the contents of kynurenine (Kyn) and 3-hydroxyanthranilic acid (3-HAA) were markedly increased. Additionally, 3-HAA was highly toxic to G. mellonella and resulted in corrected mortalities of 62.50%. Tryptophan metabolites produced by EPNs are a potential marker to kill insects, opening up a novel line of inquiry into exploring the infestation mechanism of EPNs.

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Klebsiella

Rahi,

Rodrigues,

Brisse

2024

Bergey's Manual of Systematics of Archaea and Bacteria

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Klebs.i.el' la . N.L. fem. dim. n. Klebsiella , named after Edwin Klebs (1834–1913), a German bacteriologist. Pseudomonadota / Gammaproteobacteria / Enterobacterales / Enterobacteriaceae / Klebsiella Cells are Gram‐stain‐negative straight rods (0.3–1.0 × 0.6–6.0 μm), mostly nonmotile (except K. aerogenes ), and are capsulated. Grow on a variety of growth media including meat extract media (except K. granulomatis , which has not been cultured). Colonies are smooth, circular, more or less dome shaped, and glistening of varying degrees of stickiness, depending on the strain and the composition of the medium. Klebsiella are cytochrome oxidase‐negative, mesophilic, and facultatively anaerobic, having both a respiratory and a fermentative type of metabolism. The majority of Klebsiella fail to grow at 10 and 45°C, while the type strains of K. oxytoca , K. planticola , K. terrigena , K. ornithinolytica , K. michiganensis , and K. variicola show growth at 10°C. Klebsiella are usually positive for Voges–Proskauer test, except strains of K. spallanzanii , K. indica , and K. huaxiensis . Most Klebsiella members hydrolyze urea. Based on genomic sequence‐based phylogenetic analyses, Klebsiella species form higher‐level groups, called the K. pneumoniae species complex (KpSC), K. oxytoca species complex (KoSC), and K. planticola species complex (KplanSC). Additional species complexes may be defined in the future to accommodate other species such as K. aerogenes , K. terrigena , and K. indica . Some Klebsiella strains fix atmospheric nitrogen. Members of Klebsiella are considered ubiquitous and have been isolated from diverse sources including clinical specimens from humans and animals (e.g., cows, horses, and swine, monkeys), the mammalian gut, household items, soil, water, and plants. All Klebsiella species are considered opportunistic pathogens, except for a few specific pathovars, and may harbor a variety of antimicrobial resistance genes. Some strains of the KpSC, called hypervirulent strains, and some toxigenic strains of the KoSC are considered true pathogens. DNA G + C content (mol%) : 53–58 ( T m ). Type species : Klebsiella pneumoniae Trevisan 1887 AL (basonym: Hyalococcus pneumoniae Schroeter 1886).

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Improved diagnosis of antibiotic-associated haemorrhagic colitis (AAHC) in faecal specimens by a new qualitative real-time PCR assay detecting relevant toxin genes of Klebsiella oxytoca sensu lato

Abstract: Improved diagnosis of antibiotic-associated haemorrhagic colitis (AAHC) in faecal specimens by a new qualitative real-time PCR assay detecting relevant toxin genes of Klebsiella oxytoca sensu lato

Cited by 4 publications

References 33 publications

The role of Klebsiella populations in preterm infants

The role of Klebsiella populations in preterm infants

Metabonomics reveals that entomopathogenic nematodes mediate tryptophan metabolites that kill host insects

Klebsiella

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