Stenotrophomonas riyadhensis sp. nov., isolated from a hospital floor swab

Macori, Guerrino; Al-Qahtani, Ahmed Ali; Koolman, Leonard; Althawadi, Sahar; Mutabaqani, Maysoon; Bashtawi, Rustom; Aljumaa, Sulaiman; Almaghrabi, Reem Saad; Fanning, Séamus

doi:10.1099/ijsem.0.006250

Cited by 2 publications

(1 citation statement)

References 33 publications

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“…The genus Stenotrophomonas includes at least 22 species of Gram-negative bacteria that are found in water, soil, and plant material ( https://lpsn.dsmz.de/genus/stenotrophomonas ) ( 1 – 4 ). Notable among the Stenotrophomonas species is Stenotrophomonas maltophilia , an opportunistic pathogen that causes, among other things, pneumonia and bacteremia ( 5 – 7 ).…”

Section: Introductionmentioning

confidence: 99%

Bactericidal effectors of the Stenotrophomonas maltophilia type IV secretion system: functional definition of the nuclease TfdA and structural determination of TfcB

Cobe,

Dey,

Minasov

et al. 2024

mBio

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Stenotrophomonas maltophilia expresses a type IV protein secretion system (T4SS) that promotes contact-dependent killing of other bacteria and does so partly by secreting the effector TfcB. Here, we report the structure of TfcB, comprising an N-terminal domain similar to the catalytic domain of glycosyl hydrolase (GH-19) chitinases and a C-terminal domain for recognition and translocation by the T4SS. Utilizing a two-hybrid assay to measure effector interactions with the T4SS coupling protein VirD4, we documented the existence of five more T4SS substrates. One of these was protein 20845, an annotated nuclease. A S. maltophilia mutant lacking the gene for 20845 was impaired for killing Escherichia coli , Klebsiella pneumoniae , and Pseudomonas aeruginosa . Moreover, the cloned 20845 gene conferred robust toxicity, with the recombinant E. coli being rescued when 20845 was co-expressed with its cognate immunity protein. The 20845 effector was an 899 amino-acid protein, comprised of a GHH-nuclease domain in its N-terminus, a large central region of indeterminant function, and a C-terminus for secretion. Engineered variants of the 20845 gene that had mutations in the predicted catalytic site did not impede E. coli , indicating that the antibacterial effect of 20845 involves its nuclease activity. Using flow cytometry with DNA staining, we determined that 20845, but not its mutant variants, confers a loss in DNA content of target bacteria. Database searches revealed that uncharacterized homologs of 20845 occur within a range of bacteria. These data indicate that the S. maltophilia T4SS promotes interbacterial competition through the action of multiple toxic effectors, including a potent, novel DNase. IMPORTANCE Stenotrophomonas maltophilia is a multi-drug-resistant, Gram-negative bacterium that is an emerging pathogen of humans. Patients with cystic fibrosis are particularly susceptible to S. maltophilia infection. In hospital water systems and various types of infections, S. maltophilia co-exists with other bacteria, including other pathogens such as Pseudomonas aeruginosa . We previously demonstrated that S. maltophilia has a functional VirB/D4 type VI protein secretion system (T4SS) that promotes contact-dependent killing of other bacteria. Since most work on antibacterial systems involves the type VI secretion system, this observation remains noteworthy. Moreover, S. maltophilia currently stands alone as a model for a human pathogen expressing an antibacterial T4SS. Using biochemical, genetic, and cell biological approaches, we now report both the discovery of a novel antibacterial nuclease (TfdA) and the first structural determination of a bactericidal T4SS effector (TfcB).

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Section: Introductionmentioning

confidence: 99%

Bactericidal effectors of the Stenotrophomonas maltophilia type IV secretion system: functional definition of the nuclease TfdA and structural determination of TfcB

Cobe,

Dey,

Minasov

et al. 2024

mBio

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Expanding the Stenotrophomonas maltophilia complex: phylogenomic insights, proposal of Stenotrophomonas forensis sp. nov. and reclassification of two Pseudomonas species

Nguyen,

Edwards,

Vaughn

et al. 2024

International Journal of Systematic and Evolutionary Microbiology

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A novel Stenotrophomonas species was isolated as a contaminant in viral transport media at the District of Columbia Department of Forensic Sciences Public Health Laboratory. Phylogenomic and biochemical analyses of the isolate determined that it represented a novel species within Stenotrophomonas. Related strains in public genome databases suggested that this novel species is associated with clinically acquired infections, similar to closely related Stenotrophomonas maltophilia. The name Stenotrophomonas forensis sp. nov. is proposed. Comparative genomic and phylogenetic analyses of the S. maltophilia complex reveal that Stenotrophomonas africana is an independent species and is not a later heterotypic synonym of S. maltophilia. We also propose the transfer of two misclassified Pseudomonas species into Stenotrophomonas as Stenotrophomonas beteli comb. nov. and Stenotrophomonas hibiscicola comb. nov. The type strain for S. forensis sp. nov. is DFS-20110405T (=ATCC TSD-272T=NCTC 14893T).

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Stenotrophomonas riyadhensis sp. nov., isolated from a hospital floor swab

Cited by 2 publications

References 33 publications

Bactericidal effectors of the Stenotrophomonas maltophilia type IV secretion system: functional definition of the nuclease TfdA and structural determination of TfcB

Bactericidal effectors of the Stenotrophomonas maltophilia type IV secretion system: functional definition of the nuclease TfdA and structural determination of TfcB

Expanding the Stenotrophomonas maltophilia complex: phylogenomic insights, proposal of Stenotrophomonas forensis sp. nov. and reclassification of two Pseudomonas species

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