RESUMO
We report a food-related outbreak of salmonellosis in humans caused by a nonmotile variant of Salmonella enterica serotype Typhimurium in France in 2009. This nonmotile variant had been circulating in laying hens but was not considered as Typhimurium and consequently escaped European poultry flock regulations.
Assuntos
Surtos de Doenças , Doenças Transmitidas por Alimentos/epidemiologia , Doenças Transmitidas por Alimentos/microbiologia , Infecções por Salmonella/epidemiologia , Infecções por Salmonella/microbiologia , Salmonella typhimurium/genética , Animais , Galinhas , Ovos/microbiologia , Feminino , Microbiologia de Alimentos , França/epidemiologia , Humanos , Doenças das Aves Domésticas/epidemiologia , Doenças das Aves Domésticas/microbiologia , Salmonella typhimurium/classificação , SorotipagemRESUMO
We report Salmonella enterica serotype Typhi strains with a nonclassical quinolone resistance phenotype (i.e., decreased susceptibility to ciprofloxacin but with susceptibility to nalidixic acid) associated with a nonsynonymous mutation at codon 464 of the gyrB gene. These strains, not detected by the nalidixic acid disk screening test, can result in fluoroquinolone treatment failure.
Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana , Fenótipo , Quinolonas/farmacologia , Salmonella typhi/efeitos dos fármacos , Febre Tifoide/microbiologia , Farmacorresistência Bacteriana/genética , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Genes Bacterianos/genética , Haplótipos , Humanos , Testes de Sensibilidade Microbiana , Mutação/genética , Salmonella typhi/genéticaRESUMO
Together with plague, smallpox and typhus, epidemics of dysentery have been a major scourge of human populations for centuries(1). A previous genomic study concluded that Shigella dysenteriae type 1 (Sd1), the epidemic dysentery bacillus, emerged and spread worldwide after the First World War, with no clear pattern of transmission(2). This is not consistent with the massive cyclic dysentery epidemics reported in Europe during the eighteenth and nineteenth centuries(1,3,4) and the first isolation of Sd1 in Japan in 1897(5). Here, we report a whole-genome analysis of 331 Sd1 isolates from around the world, collected between 1915 and 2011, providing us with unprecedented insight into the historical spread of this pathogen. We show here that Sd1 has existed since at least the eighteenth century and that it swept the globe at the end of the nineteenth century, diversifying into distinct lineages associated with the First World War, Second World War and various conflicts or natural disasters across Africa, Asia and Central America. We also provide a unique historical perspective on the evolution of antibiotic resistance over a 100-year period, beginning decades before the antibiotic era, and identify a prevalent multiple antibiotic-resistant lineage in South Asia that was transmitted in several waves to Africa, where it caused severe outbreaks of disease.
Assuntos
Disenteria Bacilar/epidemiologia , Disenteria Bacilar/microbiologia , Evolução Molecular , Filogeografia , Sorogrupo , Shigella dysenteriae/classificação , Shigella dysenteriae/isolamento & purificação , Farmacorresistência Bacteriana , Disenteria Bacilar/história , Genoma Bacteriano , Saúde Global , História do Século XIX , História do Século XX , História do Século XXI , Humanos , Epidemiologia Molecular , Análise de Sequência de DNA , Shigella dysenteriae/genéticaRESUMO
Laboratory surveillance systems for salmonellosis should ideally be based on the rapid serotyping and subtyping of isolates. However, current typing methods are limited in both speed and precision. Using 783 strains and isolates belonging to 130 serotypes, we show here that a new family of DNA repeats named CRISPR (clustered regularly interspaced short palindromic repeats) is highly polymorphic in Salmonella. We found that CRISPR polymorphism was strongly correlated with both serotype and multilocus sequence type. Furthermore, spacer microevolution discriminated between subtypes within prevalent serotypes, making it possible to carry out typing and subtyping in a single step. We developed a high-throughput subtyping assay for the most prevalent serotype, Typhimurium. An open web-accessible database was set up, providing a serotype/spacer dictionary and an international tool for strain tracking based on this innovative, powerful typing and subtyping tool.