Nawal El Houmami

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.

Isolation and characterization of Kingella negevensis sp. nov., a novel Kingella species detected in a healthy paediatric population

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).

Molecular Tests That Target the RTX Locus Do Not Distinguish between Kingella kingae and the Recently Described Kingella negevensis Species

ABSTRACT Kingella kingae is an important invasive pathogen in early childhood. The organism elaborates an RTX toxin presumably restricted to this species. Consequently, real-time quantitative PCR (qPCR) assays targeting the RTX locus have been developed in recent years and are gaining increasing use for the molecular diagnosis of K. kingae infections. However, the present study shows that Kingella negevensis, a Kingella species newly identified in young children, harbors an identical Kingella RTX locus, raising the question of whether K. negevensis can be misidentified as K. kingae by clinical microbiology laboratories. In silico comparison of Kingella sp. RTX and groEL genes and in vitro studies provided evidence that targeting the rtxA and rtxB genes could not differentiate between strains of K. kingae and K. negevensis, whereas targeting the groEL gene could. This prompted the design of a highly specific and sensitive qPCR assay targeting K. negevensis groEL (kngroEL). Ninety-nine culture-negative osteoarticular specimens from 99 children younger than 4 years of age were tested with a conventional 16S rRNA gene-based broad-range PCR assay and Kingella-specific rtxB, K. kingae-specific groEL (kkgroEL), and kngroEL qPCR assays. Forty-two specimens were rtxB positive, including 41 that were also kkgroEL positive and 1 (the remaining one) that was kngroEL positive. Thus, this study discloses an invasive infection caused by K. negevensis in humans and demonstrates that targeting the RTX locus cannot be used for the formal diagnosis of K. kingae infections. These findings stress the need for further studies on the epidemiology of asymptomatic carriage and invasive infections caused by K. negevensis in humans.

Evolution of Nucleotide Punctuation Marks: From Structural to Linear Signals

We present an evolutionary hypothesis assuming that signals marking nucleotide synthesis (DNA replication and RNA transcription) evolved from multi- to unidimensional structures, and were carried over from transcription to translation. This evolutionary scenario presumes that signals combining secondary and primary nucleotide structures are evolutionary transitions. Mitochondrial replication initiation fits this scenario. Some observations reported in the literature corroborate that several signals for nucleotide synthesis function in translation, and vice versa. (a) Polymerase-induced frameshift mutations occur preferentially at translational termination signals (nucleotide deletion is interpreted as termination of nucleotide polymerization, paralleling the role of stop codons in translation). (b) Stem-loop hairpin presence/absence modulates codon-amino acid assignments, showing that translational signals sometimes combine primary and secondary nucleotide structures (here codon and stem-loop). (c) Homopolymer nucleotide triplets (AAA, CCC, GGG, TTT) cause transcriptional and ribosomal frameshifts. Here we find in recently described human mitochondrial RNAs that systematically lack mono-, dinucleotides after each trinucleotide (delRNAs) that delRNA triplets include 2x more homopolymers than mitogenome regions not covered by delRNA. Further analyses of delRNAs show that the natural circular code X (a little-known group of 20 translational signals enabling ribosomal frame retrieval consisting of 20 codons {AAC, AAT, ACC, ATC, ATT, CAG, CTC, CTG, GAA, GAC, GAG, GAT, GCC, GGC, GGT, GTA, GTC, GTT, TAC, TTC} universally overrepresented in coding versus other frames of gene sequences), regulates frameshift in transcription and translation. This dual transcription and translation role confirms for X the hypothesis that translational signals were carried over from transcriptional signals.

An Outbreak of Kingella Kingae Infections Complicating a Severe Hand, Foot, And Mouth Disease Outbreak in Nice, France, 2016

We report the investigation methods for the diagnosis of an epidemic and culture-negative Kingella kingae endocarditis complicating a severe outbreak of hand, foot and mouth disease in a childcare center. The diagnosis was confirmed by polymerase chain reaction testing performed from cardiac tissue. Our findings argue for the systematic investigation of K. kingae outbreaks by using molecular tools in such context.

Draft Genome Sequence of Kingella negevensis SW7208426, the First European Strain of K. negevensis Isolated from a Healthy Child in Switzerland

ABSTRACT We report here the draft genome of Kingella negevensis strain SW7208426, isolated from the oropharynx of a healthy 6-year-old boy in Geneva, Switzerland. To our knowledge, this is the first genome report of the newly described K. negevensis species from Europe.

Targeting the Kingella Kingae groEL Gene is a Reliable Method for the Molecular Diagnosis of K. Kingae Infection and Carriage

ders teaching them. Empowering primary health care providers with anaphylaxis education and practical skills will improve patient care. We recommend that health care institutions around Australia should examine their anaphylaxis management and if gaps are identified, ASCIA online training modules for health professionals and anaphylaxis education kits containing trainers may be useful to educate health care providers/patients/carers. Please note, Epipen is the only available adrenaline auto-injector in Australia currently (Anapen is no longer available). No ethics approval was required as this was a quality improvement project; however, informed consent was obtained from all the participants.

PTCH1 mutation and local aggressiveness of odontogenic keratocystic tumors in children: is there a relationship?

Keratocystic odontogenic tumors (KCOTs) are locally aggressive jaw lesions that may be related to PTCH1 mutations in isolation or in association with nevoid basal cell carcinoma syndrome. We sought to clarify the role of PTCH1 mutation in KCOT aggressiveness. We assessed cyst pathological characteristics, Ki-67 immunostaining, and somatic and germinal PTCH1 mutation in 16 KCOTs from 10 unrelated patients. Ten PTCH1 mutations were identified in 16 tumors. All tumors with PTCH1 mutations presented the criteria of pathological aggressiveness. We also noted the presence of a chorionic epithelial structure apparently acting as a secondary germinal center in these same tumors. Ki-67 immunostaining was not associated with PTCH1 mutation. KCOTs harboring the mutation display a chorionic epithelial structure that acts as a secondary germinal center. Genetic and microenvironmental factors might interact to propel tumor development.

Paediatric Bone and Joint Infections in French Guiana: A 6 Year Retrospective Review.

The epidemiology of paediatric bone and joint infections from South America is poorly known. We herein report a retrospective study conducted in whole French Guiana from January 2010 to December 2015. Medical charts of 55 previously healthy children were analysed, identifying 27 with osteomyelitis, 22 with septic arthritis and 6 with multifocal infections and/or osteoarthritis. The male:female ratio was 2.2:1, and the mean age was 7.5 years. Eighty percent children were ≥36 months old who had predominantly osteomyelitis related to methicillin-susceptible Staphylococcus aureus (p < 0.05) in the course of neglected skin infections. Five children presented with multi-systemic infections resulting in one fatality, mainly caused by S. aureus producing Panton-Valentine leucocidin (p < 0.01). In contrast, children aged 6-36 months had more likely culture-negative infections (p < 0.05), septic arthritis and mild clinical and biological features. Further prospective studies are required to better guide rational diagnostic and therapeutic strategies.

Kingella kingae: from oropharyngeal carriage to paediatric osteoarticular infections

Advances in knowledge about Kingella kingae, and, above all, the dedication of Pablo Yagupsky for studying this pathogen, have drastically clarified the role of K. kingae as a predominant cause of invasive infections in paediatrics. Kingella kingae is currently considered as the primary etiology of osteoarticular infections (OAI) in children aged 6– 48 months [1], and a novel agent of outbreaks of invasive disease in day care centers [2]. Osteoarticular infections caused by K. kingae remain difficult to identify with classical diagnostic strategies, because this organism is notoriously fastidious to cultivate. Considering the recent medical advances and innovative approaches for the diagnosis of the disease, partly based on the significantly high detection rate of the organism in the oropharynx of ill children [3], an increase in the number of identified cases could be established worldwide [4].