RESUMEN
Campylobacter jejuni is one of the leading infectious causes of food-borne illness around the world. Its ability to persistently colonize the intestinal tract of a broad range of hosts, including food-producing animals, is central to its epidemiology since most infections are due to the consumption of contaminated food products. Using a highly saturated transposon insertion library combined with next-generation sequencing and a mouse model of infection, we have carried out a comprehensive genome-wide analysis of the fitness determinants for growth in vitro and in vivo of a highly pathogenic strain of C. jejuni. A comparison of the C. jejuni requirements to colonize the mouse intestine with those necessary to grow in different culture media in vitro, combined with isotopologue profiling and metabolic flow analysis, allowed us to identify its metabolic requirements to establish infection, including the ability to acquire certain nutrients, metabolize specific substrates, or maintain intracellular ion homeostasis. This comprehensive analysis has identified metabolic pathways that could provide the basis for the development of novel strategies to prevent C. jejuni colonization of food-producing animals or to treat human infections.
Asunto(s)
Proteínas Bacterianas/metabolismo , Infecciones por Campylobacter/microbiología , Campylobacter jejuni/fisiología , Proteínas de Transporte de Catión/metabolismo , Gastroenteritis/microbiología , Modelos Biológicos , Absorción Fisiológica , Aminoácidos/metabolismo , Animales , Antibacterianos/efectos adversos , Proteínas Bacterianas/genética , Campylobacter jejuni/crecimiento & desarrollo , Campylobacter jejuni/aislamiento & purificación , Proteínas de Transporte de Catión/genética , Elementos Transponibles de ADN , Disbiosis/inducido químicamente , Disbiosis/microbiología , Eliminación de Gen , Estudios de Asociación Genética , Genoma Bacteriano , Biblioteca Genómica , Ratones Endogámicos C57BL , Viabilidad Microbiana , Mutagénesis Insercional , MutaciónRESUMEN
Thermophilic Campylobacter species colonize the intestine of agricultural and domestic animals commensally but cause severe gastroenteritis in humans. In contrast to other enteropathogenic bacteria, Campylobacter has been considered to be non-glycolytic, a metabolic property originally used for their taxonomic classification. Contrary to this dogma, we demonstrate that several Campylobacter coli strains are able to utilize glucose as a growth substrate. Isotopologue profiling experiments with (13) C-labeled glucose suggested that these strains catabolize glucose via the pentose phosphate and Entner-Doudoroff (ED) pathways and use glucose efficiently for de novo synthesis of amino acids and cell surface carbohydrates. Whole genome sequencing of glycolytic C. coli isolates identified a genomic island located within a ribosomal RNA gene cluster that encodes for all ED pathway enzymes and a glucose permease. We could show in vitro that a non-glycolytic C. coli strain could acquire glycolytic activity through natural transformation with chromosomal DNA of C. coli and C. jejuni subsp. doylei strains possessing the ED pathway encoding plasticity region. These results reveal for the first time the ability of a Campylobacter species to catabolize glucose and provide new insights into how genetic macrodiversity through intra- and interspecies gene transfer expand the metabolic capacity of this food-borne pathogen.
Asunto(s)
Campylobacter coli/genética , Campylobacter coli/metabolismo , Glucosa/metabolismo , Glucólisis/genética , Vía de Pentosa Fosfato/genética , Animales , Infecciones por Campylobacter/microbiología , Campylobacter coli/crecimiento & desarrollo , Campylobacter jejuni/genética , Campylobacter jejuni/crecimiento & desarrollo , Campylobacter jejuni/metabolismo , Isótopos de Carbono , Pollos , ADN Bacteriano/metabolismo , Genoma Bacteriano , Islas Genómicas , Humanos , Análisis de Secuencia de ADNRESUMEN
The non-glycolytic food-borne pathogen Campylobacter jejuni successfully colonizes the intestine of various hosts in spite of its restricted metabolic properties. While several amino acids are known to be used by C. jejuni as energy sources, none of these have been found to be essential for growth. Here we demonstrated through phenotype microarray analysis that cysteine utilization increases the metabolic activity of C. jejuni. Furthermore, cysteine was crucial for its growth as C. jejuni was unable to synthesize it from sulphate or methionine. Our study showed that C. jejuni compensates this limited anabolic capacity by utilizing sulphide, thiosulphate, glutathione and the dipeptides γGlu-Cys, Cys-Gly and Gly-Cys as sulphur sources and cysteine precursors. A panel of C. jejuni mutants in putative peptidases and peptide transporters were generated and tested for their participation in the catabolism of the cysteine-containing peptides, and the predicted transporter protein CJJ81176_0236 was discovered to facilitate the growth with the dipeptide Cys-Gly, Ile-Arg and Ile-Trp. It was named Campylobacter peptide transporter A (CptA) and is the first representative of the oligopeptide transporter OPT family demonstrated to participate in the glutathione-derivative Cys-Gly catabolism in prokaryotes. Our study provides new insights into how host- and microbiota-derived substrates like sulphide, thiosulphate and short peptides are used by C. jejuni to compensate its restricted metabolic capacities.
Asunto(s)
Proteínas Bacterianas/metabolismo , Campylobacter jejuni/crecimiento & desarrollo , Cisteína/metabolismo , Endopeptidasas/metabolismo , Azufre/metabolismo , Proteínas Bacterianas/genética , Campylobacter jejuni/genética , Campylobacter jejuni/metabolismo , Endopeptidasas/genética , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , Metionina/metabolismo , Mutación , Fenotipo , Análisis de Matrices TisularesRESUMEN
INTRODUCTION: Epidemiologic data on age-related macular degeneration (AMD) are mainly based on cohort studies, including both diagnosed and undiagnosed cases. Using health claims data allows estimating epidemiological data of diagnosed subjects with AMD within the health care system using diagnosis codes from a regional claims database (AOK PLUS) to estimate the prevalence and incidence of non-exudative and exudative AMD in Germany. METHODS: Patients with AMD were identified among AOK PLUS insured patients based on at least two outpatient, ophthalmologic or one inpatient H35.3 diagnoses for the years 2012 to 2021. Patients without continuous observation in a calendar year were excluded. Prevalence was assessed, and 1-year cumulative incidence was determined by the number of newly diagnosed patients divided by the number of individuals at risk. For 2020 and 2021, the AMD stage was assessed by diagnostic subcodes for non-exudative and exudative AMD, respectively. For 2012 to 2019, patient numbers were estimated based on the average proportions of non-exudative AMD and exudative AMD, respectively, in 2020 and 2021. Incidence and prevalence numbers were then extrapolated to Germany. RESULTS: Between 2012 to 2021, the prevalence of diagnosed AMD cases remained relatively stable among approximately 3.27 million AOK PLUS insured persons, ranging from 0.96% (minimum in 2021) to 1.31% (maximum in 2014) for non-exudative AMD, about twice as high as for exudative AMD (min-max: 0.53-0.72%). The age- and sex-adjusted projections amounted to 644,153 diagnosed non-exudative and 367,086 diagnosed German patients with exudative AMDs in 2021. The 1-year cumulative incidence for non-exudative and exudative AMD, respectively, ranged from 122,427-142,932 to 46,092-86,785 newly diagnosed cases. CONCLUSION: The number of diagnosed cases with AMD in Germany has increased slightly over the past decade. For the first time, patient counts with non-exudative and exudative AMD were approximated for Germany based on a representative, large-scale database study.