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1.
Nat Commun ; 14(1): 4281, 2023 07 17.
Artículo en Inglés | MEDLINE | ID: mdl-37460464

RESUMEN

The bacterial genus Kingella includes two pathogenic species, namely Kingella kingae and Kingella negevensis, as well as strictly commensal species. Both K. kingae and K. negevensis secrete a toxin called RtxA that is absent in the commensal species. Here we present a phylogenomic study of the genus Kingella, including new genomic sequences for 88 clinical isolates, genotyping of another 131 global isolates, and analysis of 52 available genomes. The phylogenetic evidence supports that the toxin-encoding operon rtxCA was acquired by a common ancestor of the pathogenic Kingella species, and that a preexisting type-I secretion system was co-opted for toxin export. Subsequent genomic reorganization distributed the toxin machinery across two loci, with 30-35% of K. kingae strains containing two copies of the rtxA toxin gene. The rtxA duplication is largely clonal and is associated with invasive disease. Assays with isogenic strains show that a single copy of rtxA is associated with reduced cytotoxicity in vitro. Thus, our study identifies key steps in the evolutionary transition from commensal to pathogen, including horizontal gene transfer, co-option of an existing secretion system, and gene duplication.


Asunto(s)
Toxinas Bacterianas , Kingella kingae , Filogenia , Virulencia/genética , Toxinas Bacterianas/genética , Kingella/genética , Kingella kingae/genética
2.
Am J Trop Med Hyg ; 103(2): 672-674, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32431277

RESUMEN

We report a patient with risk factors for both microbial keratitis and endophthalmitis, which were initially challenging to distinguish. Cultures of corneal scrapings yielded several organisms, including an uncultivable Gram-negative rod, eventually identified as Kingella negevensis. Kingella negevensis is so named because most strains have been isolated in the Negev, a desert region of southern Israel. The epidemiology of K. negevensis remains incompletely understood. We found no other reports in the literature of this organism causing microbial keratitis.


Asunto(s)
Trastornos Relacionados con Cocaína/complicaciones , Cocaína/administración & dosificación , Inhibidores de Captación de Dopamina/administración & dosificación , Endoftalmitis/complicaciones , Queratitis/complicaciones , Infecciones por Neisseriaceae/complicaciones , Infecciones Estreptocócicas/complicaciones , Abuso de Sustancias por Vía Intravenosa/complicaciones , Administración Oftálmica , Adulto , Antiinflamatorios/uso terapéutico , Antioxidantes/uso terapéutico , Ácido Ascórbico/uso terapéutico , Ceftazidima/uso terapéutico , Coinfección/complicaciones , Coinfección/diagnóstico , Coinfección/tratamiento farmacológico , Doxiciclina/uso terapéutico , Endoftalmitis/diagnóstico , Endoftalmitis/tratamiento farmacológico , Endoftalmitis/microbiología , Femenino , Infecciones por Bacterias Grampositivas/complicaciones , Infecciones por Bacterias Grampositivas/diagnóstico , Infecciones por Bacterias Grampositivas/tratamiento farmacológico , Infecciones por Bacterias Grampositivas/microbiología , Humanos , Queratitis/diagnóstico , Queratitis/tratamiento farmacológico , Queratitis/microbiología , Kingella/genética , Kingella/aislamiento & purificación , Linezolid/uso terapéutico , Moxifloxacino/uso terapéutico , Infecciones por Neisseriaceae/diagnóstico , Infecciones por Neisseriaceae/tratamiento farmacológico , Infecciones por Neisseriaceae/microbiología , Soluciones Oftálmicas , Prednisona/uso terapéutico , Propionibacterium acnes/aislamiento & purificación , Infecciones Estreptocócicas/diagnóstico , Infecciones Estreptocócicas/tratamiento farmacológico , Infecciones Estreptocócicas/microbiología , Streptococcus/aislamiento & purificación , Tobramicina/uso terapéutico , Vancomicina/uso terapéutico , Voriconazol/uso terapéutico
3.
J Clin Microbiol ; 56(10)2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30045866

RESUMEN

The recognition of the role of Kingella kingae as one of the main etiologic agents of skeletal system infections in young children and the recent discovery of the novel Kingella negevensis species have resulted in an increasing interest in these two emerging pediatric pathogens. Both bacteria colonize the oropharynx and are not detected in nasopharyngeal specimens, and the colonized mucosal surface is their portal of entry to the bloodstream. Although species-specific nucleic acid amplification assays have significantly improved the detection of kingellae and facilitated patients' management, the increasing use of this diagnostic approach has the potential drawback of neglecting culture recovery of these organisms. The isolation of Kingella species enables the thorough genotyping of strains for epidemiological purposes, the study of the dynamics of asymptomatic colonization and person-to-person transmission, the investigation of the pathogenesis of invasive infections, and the determination of antibiotic susceptibility patterns. The culture isolation of pharyngeal strains and their comparison with isolates derived from normally sterile body sites may also aid in identifying virulence factors involved in the transition from colonization to invasive disease which could represent potential targets for a future protective vaccine. The two species are notoriously fastidious, and their isolation from upper respiratory tract specimens requires a short transport time, plating on selective vancomycin-containing blood-agar medium, and incubation under capnophilic and aerobic conditions. The identification of K. kingae and K. negevensis can be performed by a combination of the typical Gram stain and biochemical tests and confirmed and differentiated by molecular assays that target the groEL and mdh genes.


Asunto(s)
Kingella/aislamiento & purificación , Infecciones por Neisseriaceae/diagnóstico , Infecciones por Neisseriaceae/microbiología , Orofaringe/microbiología , Niño , Medios de Cultivo , Genotipo , Humanos , Kingella/clasificación , Kingella/genética , Kingella/patogenicidad , Kingella kingae/clasificación , Kingella kingae/genética , Kingella kingae/aislamiento & purificación , Kingella kingae/patogenicidad , Fenotipo , Virulencia
4.
Microbes Infect ; 19(11): 546-552, 2017 11.
Artículo en Inglés | MEDLINE | ID: mdl-28802585

RESUMEN

Kingella kingae, producing the cytotoxic RTX protein, is a causative agent of serious infections in humans such as bacteremia, endocarditis and osteoarticular infection, especially in young children. Recently, Kingella negevensis, a related species, has been isolated from the oral cavity of healthy children. In this study, we report the isolation of K. negevensis strain eburonensis, initially misidentified as K. kingae with MALDI-TOF MS, from a vaginal specimen of a patient suffering of vaginosis. The genome sequencing and analysis of this strain together with comparative genomics of the Kingella genus revealed that K. negevensis possesses a full homolog of the rtx operon of K. kingae involved in the synthesis of the RTX toxin. We report that a K. kingae specific diagnostic PCR, based on the rtxA gene, was positive when tested on K. negevensis strain eburonensis DNA. This cross-amplification, and risk of misidentification, was confirmed by in silico analysis of the target gene sequence. To overcome this major diagnostic issue we developed a duplex real-time PCR to detect and distinguish K. kingae and K. negevensis. In addition to this, the identification of K. negevensis raises a clinical issue in term of pathogenic potential given the production of a RTX hemolysin.


Asunto(s)
Toxinas Bacterianas/genética , Kingella/genética , Infecciones por Neisseriaceae/diagnóstico , Femenino , Genómica , Humanos , Kingella/aislamiento & purificación , Infecciones por Neisseriaceae/genética , Infecciones por Neisseriaceae/microbiología , Filogenia , ARN Ribosómico 16S/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Vaginosis Bacteriana/microbiología , Adulto Joven
5.
Int J Syst Evol Microbiol ; 67(7): 2370-2376, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28699877

RESUMEN

We herein report the isolation and characterization of 21 Gram-stain-negative strains cultivated from the oropharynx of healthy children in Israel and Switzerland. Initially described as small colony variants of Kingella kingae, phenotypic analysis, biochemical analysis, phylogenetic analysis based on sequencing of the partial 16S rRNA gene and five housekeeping genes (abcZ, adk, G6PD, groEL and recA), and whole genome sequencing and comparison between members of the genera Kingella and Neisseria provided evidence for assigning them to the genus Kingella. Cellular fatty acids included important amounts of C12 : 0, C14 : 0, C16 : 0 and C16 : 1n7. Digital DNA-DNA hybridization between the isolates Sch538T and K. kingae ATCC 23330T revealed relatedness of 19.9 %. Comparative analysis of 16S rRNA gene sequences available in GenBank allowed matches to strains isolated in the USA, suggesting a wider geographical distribution. A novel species named Kingella negevensis sp. nov. is proposed, as most strains have been isolated in the Negev, a desert region of southern Israel. The type strain is Sch538T (=CCUG 69806T=CSUR P957).


Asunto(s)
Kingella/clasificación , Orofaringe/microbiología , Filogenia , Técnicas de Tipificación Bacteriana , Composición de Base , Niño , ADN Bacteriano/genética , Ácidos Grasos/química , Genes Bacterianos , Humanos , Israel , Kingella/genética , Kingella/aislamiento & purificación , Hibridación de Ácido Nucleico , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Suiza
6.
Nat Commun ; 6: 10172, 2015 Dec 16.
Artículo en Inglés | MEDLINE | ID: mdl-26671256

RESUMEN

The Neisseriaceae family of bacteria causes a range of diseases including meningitis, septicaemia, gonorrhoea and endocarditis, and extracts haem from haemoglobin as an important iron source within the iron-limited environment of its human host. Herein we report crystal structures of apo- and haemoglobin-bound HpuA, an essential component of this haem import system. The interface involves long loops on the bacterial receptor that present hydrophobic side chains for packing against the surface of haemoglobin. Interestingly, our structural and biochemical analyses of Kingella denitrificans and Neisseria gonorrhoeae HpuA mutants, although validating the interactions observed in the crystal structure, show how Neisseriaceae have the fascinating ability to diversify functional sequences and yet retain the haemoglobin binding function. Our results present the first description of HpuA's role in direct binding of haemoglobin.


Asunto(s)
Proteínas Bacterianas/metabolismo , Hemoglobinas/metabolismo , Kingella/metabolismo , Neisseria gonorrhoeae/metabolismo , Receptores de Superficie Celular/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Cristalización , Humanos , Kingella/genética , Neisseria gonorrhoeae/genética , Neisseriaceae/genética , Neisseriaceae/metabolismo , Unión Proteica , Estructura Terciaria de Proteína , Receptores de Superficie Celular/química , Receptores de Superficie Celular/genética
7.
J Clin Microbiol ; 43(7): 3526-9, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-16000497

RESUMEN

We report the isolation and characterization of a hitherto unknown gram-negative, rod-shaped Neisseria-like organism from an infected wound resulting from a bite from a kinkajou. Based on both phenotypic and phylogenetic evidence, it is proposed that the unknown organism be classified as a new species, Kingella potus sp. nov.


Asunto(s)
Mordeduras y Picaduras , Carnívoros , Kingella/clasificación , Infecciones por Neisseriaceae/microbiología , Infección de Heridas/microbiología , Animales , ADN Ribosómico/análisis , Genes de ARNr , Kingella/genética , Kingella/aislamiento & purificación , Datos de Secuencia Molecular , Fenotipo , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN
8.
Gene ; 192(1): 171-6, 1997 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-9224888

RESUMEN

Kingella denitrificans possess type-4 pili, and the type strain, ATCC 33394, contains at least four complete copies of type-4 pilin-encoding genes. Previously reported hybridization patterns of K. denitrificans chromosomal DNA seen using a Neisseria gonorrhoeae pilin gene region probe, had been interpreted as representing possible partial, silent gene loci. This now appears to be due to cross-reaction to multiple copies of 18-bp inverted repeat structures. Data are presented on a variety of colony variants which have changed from a spreading-corroding (SC) phenotype to a nonspreading-noncorroding (N) phenotype. Interestingly, while the SC to N transition is most often associated with loss of piliation in other bacteria containing type-4 pili, many of the K. denitrificans N variants still produce pilin, and some still produce pili.


Asunto(s)
Proteínas de la Membrana Bacteriana Externa/genética , Fimbrias Bacterianas/química , Genes Bacterianos , Kingella/química , Southern Blotting , Western Blotting , Sondas de ADN , Proteínas Fimbrias , Fimbrias Bacterianas/genética , Dosificación de Gen , Regulación Bacteriana de la Expresión Génica , Kingella/genética , Kingella/patogenicidad , Microscopía Electrónica , Fenotipo
9.
Infect Immun ; 64(12): 4993-9, 1996 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8945537

RESUMEN

We have cloned and sequenced four complete type 4 pilin genes from the type strain (ATCC 33394) of Kingella denitrificans. Two of these pilin genes, kdpB and kdpD, are in tandem, oriented in the same direction, and encode pilins of only 50% amino acid identity. The kdpA and kdpC loci are separately located from the kdpB-kdpD locus and from each other. At the DNA level kdpA and kdpC are nearly identical to kdpB and encode pilin proteins that are identical to KdpB. Bands of multiple hybridization previously hypothesized to be due to partial silent pilin gene loci are now shown to be due to the presence of 18-bp repeat sequences (IR18) associated with the pilin gene coding regions. These IR18 sequences exist most often as inverted repeats separated by 8 bp. IR18 sequences are structurally similar to the repetitive extragenic palindromic sequences of Escherichia coli, although they have different DNA sequences. The IR18 sequences also demonstrate homology to the DNA uptake sequences of Neisseria gonorrhoeae and may serve a similar function for K. denitrificans.


Asunto(s)
Proteínas de la Membrana Bacteriana Externa/genética , ADN Bacteriano/genética , Genes Bacterianos , Genoma Bacteriano , Kingella/genética , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , ADN Bacteriano/análisis , Proteínas Fimbrias , Datos de Secuencia Molecular , Alineación de Secuencia
10.
Mol Cell Probes ; 9(5): 327-32, 1995 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8569773

RESUMEN

Forty-four Neisseria gonorrhoeae, 12 N. meningitidis, four Kingella denitrificans and one Eikenella corrodens carrying 25.2 MDa Tet M plasmids were analysed using polymerase chain reaction (PCR) to the downstream region of the incomplete Tet M transposon. From each isolate, one of two different PCR fragments of approximately 700 or 1600 bp were obtained. The two different sized PCR fragments had > or = 90% DNA sequence identity with Ureaplasma urealyticum Tet M downstream sequences. The difference between the large PCR fragment and the smaller PCR fragment was a deletion of over 800 bp in the smaller fragment. Both PCR fragments were found in plasmids isolated from N. gonorrhoeae and K. denitrificans. The smaller PCR fragment was found in N. meningitidis plasmids and the larger PCR fragment was found in the E. corrodens plasmid.


Asunto(s)
Proteínas Bacterianas/genética , Eikenella corrodens/genética , Kingella/genética , Neisseria gonorrhoeae/genética , Neisseria meningitidis/genética , Resistencia a la Tetraciclina/genética , Secuencia de Bases , Cartilla de ADN , Elementos Transponibles de ADN , ADN Bacteriano/genética , Eikenella corrodens/aislamiento & purificación , Humanos , Kingella/aislamiento & purificación , Datos de Secuencia Molecular , Neisseria gonorrhoeae/aislamiento & purificación , Neisseria meningitidis/aislamiento & purificación , Reacción en Cadena de la Polimerasa/métodos , Factores R , Homología de Secuencia de Ácido Nucleico , Ureaplasma urealyticum/genética
11.
Int J Syst Bacteriol ; 44(3): 387-91, 1994 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-7520730

RESUMEN

We obtained 16S ribosomal DNA (rDNA) sequence data for strains belonging to 11 species of Proteobacteria, including the type strains of Kingella kingae, Neisseria lactamica, Neisseria meningitidis, Moraxella lacunata subsp. lacunata, [Neisseria] ovis, Moraxella catarrhalis, Moraxella osloensis, [Moraxella] phenylpyruvica, and Acinetobacter lwoffii, as well as strains of Neisseria subflava and Acinetobacter calcoaceticus. The data in a distance matrix constructed by comparing the sequences supported the proposal that the genera Acinetobacter and Moraxella and [N.] ovis should be excluded from the family Neisseriaceae. Our results are consistent with hybridization data which suggest that these excluded taxa should be part of a new family, the Moraxellaceae. The strains that we studied can be divided into the following five groups: (i) M. lacunata subsp. lacunata, [N.] ovis, and M. catarrhalis; (ii) M. osloensis; (iii) [M.] phenylpyruvica; (iv) A. calcoaceticus and A. lwoffii; and (v) N. meningitidis, N. subflava, N. lactamica, and K. kingae. We agree with the previous proposal that [N.] ovis should be renamed Moraxella ovis, as this organism is closely related to Moraxella species and not to Neisseria species. The generically misnamed taxon [M.] phenylpyruvica belongs to the proposed family Moraxellaceae, but it is sufficiently different to warrant exclusion from the genus Moraxella. Further work needs to be done to investigate genetically similar species, such as Psychrobacter immobilis, before the true generic position of this organism can be determined. Automated 16S rDNA sequencing with the PCR allows workers to accurately determine phylogenetic relationships between groups of organisms.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
ADN Bacteriano/genética , ADN Ribosómico/genética , Neisseriaceae/clasificación , Neisseriaceae/genética , Acinetobacter/clasificación , Acinetobacter/genética , Secuencia de Bases , Cartilla de ADN/genética , Kingella/clasificación , Kingella/genética , Datos de Secuencia Molecular , Moraxella/clasificación , Moraxella/genética , Neisseria/clasificación , Neisseria/genética , Filogenia , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Homología de Secuencia de Ácido Nucleico , Especificidad de la Especie
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