RESUMEN
A bacterial insertion sequence (IS) is a mobile DNA sequence carrying only the transposase gene (tnp) that acts as a mutator to disrupt genes, alter gene expressions, and cause genomic rearrangements. "Canonical" ISs have historically been characterized by their terminal inverted repeats (IRs), which may form a stem-loop structure, and duplications of a short (non-IR) target sequence at both ends, called target site duplications (TSDs). The IS distributions and virulence potentials of Staphylococcus aureus genomes in familial infection cases are unclear. Here, we determined the complete circular genome sequences of familial strains from a Panton-Valentine leukocidin (PVL)-positive ST50/agr4 S. aureus (GN) infection of a 4-year old boy with skin abscesses. The genomes of the patient strain (GN1) and parent strain (GN3) were rich for "canonical" IS1272 with terminal IRs, both having 13 commonly-existing copies (ce-IS1272). Moreover, GN1 had a newly-inserted IS1272 (ni-IS1272) on the PVL-converting prophage, while GN3 had two copies of ni-IS1272 within the DNA helicase gene and near rot. The GN3 genome also had a small deletion. The targets of ni-IS1272 transposition were IR structures, in contrast with previous "canonical" ISs. There were no TSDs. Based on a database search, the targets for ce-IS1272 were IRs or "non-IRs". IS1272 included a larger structure with tandem duplications of the left (IRL) side sequence; tnp included minor cases of a long fusion form and truncated form. One ce-IS1272 was associated with the segments responsible for immune evasion and drug resistance. Regarding virulence, GN1 expressed cytolytic peptides (phenol-soluble modulin α and δ-hemolysin) and PVL more strongly than some other familial strains. These results suggest that IS1272 transposes through an IR-replacing mechanism, with an irreversible process unlike that of "canonical" transpositions, resulting in genomic variations, and that, among the familial strains, the patient strain has strong virulence potential based on community-associated virulence factors.
Asunto(s)
Elementos Transponibles de ADN/genética , Genómica , Secuencias Invertidas Repetidas/genética , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/genética , Staphylococcus aureus/aislamiento & purificación , Toxinas Bacterianas/química , Toxinas Bacterianas/genética , Secuencia de Bases , Preescolar , Mapeo Cromosómico , Análisis por Conglomerados , ADN Circular/genética , Exotoxinas/química , Exotoxinas/genética , Familia , Femenino , Duplicación de Gen , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos , Genoma Bacteriano , Humanos , Leucocidinas/química , Leucocidinas/genética , Masculino , Mutagénesis Insercional/genética , Reacción en Cadena de la Polimerasa , Profagos/fisiología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Análisis de Secuencia de ADN , Infecciones Estafilocócicas/transmisión , Staphylococcus aureus/patogenicidad , Factores de Virulencia/biosíntesis , Factores de Virulencia/genéticaRESUMEN
Paraneoplastic pemphigus (PNP) is an autoimmune mucocutaneous disease, associated with neoplasia, which has characteristic clinical, histological and immunological features. While respiratory epithelial involvement has been described in several cases, lesions in the colon epithelium have never been reported. We describe a 57-year-old Japanese woman with PNP who had many aphthae-like erosions on the colon epithelium, in addition to typical mucocutaneous PNP lesions. The intestinal erosions had histological features similar to those of PNP and linear deposition of complement, but not IgG, was observed along the colon epithelial basement membrane.