The Type a and Type b Polysaccharide Capsules Predominate in an International Collection of Invasive Kingella kingae Isolates

Porsch, Eric A.; Starr, Kimberly; Yagupsky, Pablo; Geme, Joseph W. St.

doi:10.1128/msphere.00060-17

Cited by 21 publications

(24 citation statements)

References 15 publications

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“…The four distinct capsule types of K. kingae promote serum survival in isogenic strains. To date, a total of four distinct capsule types have been identified in diverse collections of K. kingae clinical isolates, including type a ( (19)(20)(21)(22). The prototype strain KK01 used in this study expresses the type a capsule.…”

Section: Opsonin Deposition Is Increased In the Absence Of Surface Pomentioning

confidence: 99%

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Kingella kingae Surface Polysaccharides Promote Resistance to Human Serum and Virulence in a Juvenile Rat Model

2018

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is a Gram-negative coccobacillus that is increasingly being recognized as an important cause of invasive disease in young children. The pathogenesis of disease begins with colonization of the oropharynx, followed by invasion of the bloodstream, survival in the intravascular space, and dissemination to distant sites. Recent studies have revealed that produces a number of surface factors that may contribute to the pathogenic process, including a polysaccharide capsule and an exopolysaccharide. In this study, we observed that was highly resistant to the bactericidal effects of human serum complement. Using mutant strains deficient in expression of capsule, exopolysaccharide, or both in assays with human serum, we found that elimination of both capsule and exopolysaccharide was required for efficient binding of IgG, IgM, C4b, and C3b to the bacterial surface and for complement-mediated killing. Abrogation of the classical complement pathway using EGTA-treated human serum restored survival to wild-type levels by the mutant lacking both capsule and exopolysaccharide, demonstrating that capsule and exopolysaccharide promote resistance to the classical complement pathway. Consistent with these results, loss of both capsule and exopolysaccharide eliminated invasive disease in juvenile rats with an intact complement system but not in rats lacking complement. Based on these observations, we conclude that the capsule and the exopolysaccharide have important redundant roles in promoting survival of in human serum. Each of these surface factors is sufficient by itself to fully prevent serum opsonin deposition and complement-mediated killing of , ultimately facilitating intravascular survival and promoting invasive disease.

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Section: Opsonin Deposition Is Increased In the Absence Of Surface Pomentioning

confidence: 99%

“…In K. kingae, four distinct polysaccharide capsules, designated types a, b, c, and d, have been identified (19). Capsule types a and b account for greater than 95% of invasive disease isolates (19,20). Previous work has demonstrated that the capsule is required for full K. kingae virulence in a juvenile rat model of invasive disease (21,22).…”

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Kingella kingae Surface Polysaccharides Promote Resistance to Human Serum and Virulence in a Juvenile Rat Model

2018

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“…To our knowledge, no epidemiological data on the healthy carriage is available in France. We aimed to determine the rate of and the factors associated with healthy carriage of K. kingae in young children in France, as well as the capsular serotype of these strains, known to be associated either with invasive or carriage strains [3].…”

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Prevalence of Kingella kingae oropharyngeal carriage and predominance of type a and type b polysaccharide capsules among French young children

Basmaci

Deschamps

Lévy

et al. 2019

Clinical Microbiology and Infection

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“…Research conducted using a large assortment of international isolates recovered from asymptomatic respiratory carriers and patients with a variety of clinical infections has revealed that K. kingae elaborates a polysaccharide capsule and an exopolysaccharide that confer invasiveness in juvenile animal models (14)(15)(16). Two capsule types (namely, a and b) appear to have enhanced pathogenic properties and are detected in 95% of all isolates from patients with invasive diseases, irrespective of their geographical origin (17,18). Interestingly, capsules c and d are significantly more abundant in isolates from healthy pharyngeal carriers (17).…”

Section: Typing K Kingae Isolates: Invasive Strains and Mucosal Colomentioning

confidence: 99%

Detection of Respiratory Colonization by Kingella kingae and the Novel Kingella negevensis Species in Children: Uses and Methodology

Yagupsky

2018

J Clin Microbiol

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The recognition of the role of as one of the main etiologic agents of skeletal system infections in young children and the recent discovery of the novel 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 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 and can be performed by a combination of the typical Gram stain and biochemical tests and confirmed and differentiated by molecular assays that target the and genes.

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The Type a and Type b Polysaccharide Capsules Predominate in an International Collection of Invasive Kingella kingae Isolates

Cited by 21 publications

References 15 publications

Kingella kingae Surface Polysaccharides Promote Resistance to Human Serum and Virulence in a Juvenile Rat Model

Kingella kingae Surface Polysaccharides Promote Resistance to Human Serum and Virulence in a Juvenile Rat Model

Prevalence of Kingella kingae oropharyngeal carriage and predominance of type a and type b polysaccharide capsules among French young children

Detection of Respiratory Colonization by Kingella kingae and the Novel Kingella negevensis Species in Children: Uses and Methodology

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