Romain Basmaci

Investigation of an outbreak of osteoarticular infections caused by Kingella kingae in a childcare center using molecular techniques.

We describe an outbreak of 5 osteoarticular infections among 24 daycare center attendees. Polymerase chain reaction revealed Kingella kingae in the joint fluid of 1 child and in 85% of throat samples from healthy contacts. Multilocus sequence typing performed on the joint fluid and carriage isolates identified an unique sequence type. Rifampin failed to eradicate K. kingae carriage.

Comparison of clinical and biologic features of Kingella kingae and Staphylococcus aureus arthritis at initial evaluation.

We conducted a retrospective study comparing the presenting clinical and biologic features of 64 children who had septic arthritis caused by Kingella kingae with 26 children who had septic arthritis caused by Staphylococcus aureus. Children with K. kingae septic arthritis were significantly younger than those with S. aureus septic arthritis. Otherwise, there were no significant differences between the 2 groups with respect to fever, location, white blood cell count, synovial fluid cell count, C-reactive protein, or serum fibrinogen. However, the clinical course was significantly better for children with septic arthritis caused by K. kingae as evidenced by shorter hospitalization and fewer adverse events. Presumptive antibiotic therapy for septic arthritis in young infants should take into account both of these pathogens, even in case of mild presentation.

Isolation of Kingella kingae in the oropharynx during K. kingae arthritis in children

Kingella kingae arthritis in children is now mainly diagnosed by PCR, which has surpassed conventional culture of joint fluid. As oropharynx colonization is the first step of Kingella kingae invasion, we prospectively investigated the possibility of cultivating it from throat swabs, in children hospitalized for K. kingae arthritis. Throat culture was 5.6-fold more sensitive than joint fluid cultures in isolating K. kingae (66.7% vs. 11.9% respectively, p <0.001) and may be used to perform antibiotic susceptibility testing.

Multilocus Sequence Typing and rtxA Toxin Gene Sequencing Analysis of Kingella kingae Isolates Demonstrates Genetic Diversity and International Clones

Background Kingella kingae, a normal component of the upper respiratory flora, is being increasingly recognized as an important invasive pathogen in young children. Genetic diversity of this species has not been studied. Methods We analyzed 103 strains from different countries and clinical origins by a new multilocus sequence-typing (MLST) schema. Putative virulence gene rtxA, encoding an RTX toxin, was also sequenced, and experimental virulence of representative strains was assessed in a juvenile-rat model. Results Thirty-six sequence-types (ST) and nine ST-complexes (STc) were detected. The main STc 6, 14 and 23 comprised 23, 17 and 20 strains respectively, and were internationally distributed. rtxA sequencing results were mostly congruent with MLST, and showed horizontal transfer events. Of interest, all members of the distantly related ST-6 (n = 22) and ST-5 (n = 4) harboured a 33 bp duplication or triplication in their rtxA sequence, suggesting that this genetic trait arose through selective advantage. The animal model revealed significant differences in virulence among strains of the species. Conclusion MLST analysis reveals international spread of ST-complexes and will help to decipher acquisition and evolution of virulence traits and diversity of pathogenicity among K. kingae strains, for which an experimental animal model is now available.

Major Intercontinentally Distributed Sequence Types of Kingella kingae and Development of a Rapid Molecular Typing Tool

ABSTRACT Although Kingella kingae is the most common etiology of osteoarticular infections in young children, is a frequent cause of bacteremia in those younger than 4 years, and has been involved in clusters of invasive infections among daycare center attendees, the population structure of the species has not been systematically studied. Using multilocus sequence typing, we investigated the genetic diversity of the largest intercontinental collection of K. kingae strains to date. To facilitate typing of bacterial isolates, we developed a novel genotyping tool that targets the DNA uptake sequence (DUS). Among 324 strains isolated from asymptomatic carriers and patients from Israel, Europe, North America, and Australia with various invasive forms of the disease from 1960 to 2013, we identified 64 sequence types (STs) and 12 ST complexes (STcs). Five predominant STcs, comprising 72.2% of all strains, were distributed intercontinentally. ST-6 was the most frequent, showing a worldwide distribution, and appeared genotypically isolated by exhibiting few neighboring STs, suggesting an optimal fitness. ST-14 and ST-23 appeared to be the oldest groups of bacteria, while ST-25 probably emerged more recently from the highly evolutive ST-23. Using the DUS typing method, randomly chosen isolates were correctly classified to one of the major STcs. The comprehensive description of K. kingae evolution would help to detect new emerging clones and decipher virulence and fitness mechanisms. The rapid and reproducible DUS typing method may serve in the initial investigation of K. kingae outbreaks.

Patterns of Kingella kingae Disease Outbreaks.

Background: Kingella kingae outbreaks occur sporadically in childcare centers but remain poorly understood and difficult to identify. Methods: To provide the basis of a better knowledge of K. kingae outbreaks patterns that may help to guide identification and management strategies, we collected epidemiological, clinical and laboratory data from all reported K. kingae outbreaks, and those from 2 new Israel outbreaks in 2014. Results: Nine outbreaks were identified in the USA, Israel and France from 2003 to 2014. Twenty-seven children with a median age of 14 ± 4.1 months were affected, male:female ratio of 1.4:1. Outbreaks demonstrated seasonal patterns from the 10th to the 45th weeks, a mean duration of 13.1 ± 8.4 days, a mean attack rate of 17.3 ± 5.1% and a case-fatality rate of 3.7% (1/27). Seventy-four percentage of children had fever (20/27), and the mean values of white blood cell count and C-reactive protein level were 14.6 ± 4.5 × 109/L and 23.8 ± 24.1 mg/L, respectively. Osteoarticular infections accounted for 88.9% of cases (24/27), bacteremia 7.4% (2/27), endocarditis 3.7% (1/27) and meningitis 3.7% (1/27). Specific real-time polymerase chain reaction demonstrated higher performance than culture methods in the diagnosis of case patients and investigations of oropharyngeal K. kingae carriage among close contacts, and multilocus sequence typing methods revealed that ST-6 and ST-25 invasive strains were responsible for multiple country-dependent outbreaks. Coviral infections were identified in the majority of K. kingae outbreaks, notably those causing oral ulcers. Conclusions: K. kingae outbreaks displayed severe K. kingae diseases that were poorly confirmed with culture methods. We argue for the use of genomic technologies to investigate further K. kingae outbreaks.

High respiratory virus oropharyngeal carriage rate during Kingella kingae osteoarticular infections in children.

AIM Kingella kingae osteoarticular (KKO) infections are frequently associated with upper respiratory tract infections. However, no comparative studies detecting respiratory viruses had ever been performed between KKO and non-KKO (NKO). PATIENTS & METHODS Eighteen viruses were searched by FilmArray(®) Respiratory Panel (BioFire Diagnostics, UT, USA) in the oropharynx of 6-to-48-month-children admitted for KKO and NKO in 2013. RESULTS At least one virus was detected in the oropharynx of 19/21 (90.5%) KKO and 3/8 (37.5%) NKO cases (p = 0.008). In KKO group, human rhinovirus was predominant (12/21; 57.1%), especially during winter (7/11; 63.6%) despite its low concomitant circulation (<10%). Human rhinovirus was found in 2/8 (25%) in NKO group. CONCLUSION Higher prevalence of respiratory virus in oropharynx was observed in KKO than NKO, strengthening their putative role in KKO pathophysiology.

Enteroviral Meningitis Does Not Exclude Concurrent Bacterial Meningitis

We read with interest the study of Nolte et al. ([6][1]) evaluating a completely automated enteroviral real-time PCR assay (EV-PCR) with cerebrospinal fluid (CSF). Among 434 patients, 113 (26%) had enteroviral meningitis with no bacterial coinfection. Six patients had bacterial meningitis with EV-

First Identification of a Chromosomally Located Penicillinase Gene in Kingella kingae Species Isolated in Continental Europe

ABSTRACT Kingella kingae is the major pathogen causing osteoarticular infections (OAI) in young children in numerous countries. Plasmid-borne TEM-1 penicillinase production has been sporadically detected in a few countries but not in continental Europe, despite a high prevalence of K. kingae infections. We describe here for the first time a K. kingae β-lactamase-producing strain in continental Europe and demonstrate the novel chromosomal location of the blaTEM-1 gene in K. kingae species.

Genome Analysis of Kingella kingae Strain KWG1 Reveals How a β-Lactamase Gene Inserted in the Chromosome of This Species

ABSTRACT We describe the genome of a penicillinase-producing Kingella kingae strain (KWG1), the first to be isolated in continental Europe, whose blaTEM-1 gene was, for the first time in this species, found to be chromosomally inserted. The blaTEM gene is located in an integrative and conjugative element (ICE) inserted in Met-tRNA and comprising genes that encode resistance to sulfonamides, streptomycin, and tetracycline. This ICE is homologous to resistance-conferring plasmids of K. kingae and other Gram-negative bacteria.