RESUMO
Consumption of raw, undercooked or contaminated animal food products is a frequent cause of Campylobacter jejuni infection. Brazil is the world's third largest producer and a major exporter of chicken meat, yet population-level genomic investigations of C. jejuni in the country remain scarce. Analysis of 221 C. jejuni genomes from Brazil shows that the overall core and accessory genomic features of C. jejuni are influenced by the identity of the human or animal source. Of the 60 sequence types detected, ST353 is the most prevalent and consists of samples from chicken and human sources. Notably, we identified the presence of diverse bla genes from the OXA-61 and OXA-184 families that confer beta-lactam resistance as well as the operon cmeABCR related to multidrug efflux pump, which contributes to resistance against tetracyclines, macrolides and quinolones. Based on limited data, we estimated the most recent common ancestor of ST353 to the late 1500s, coinciding with the time the Portuguese first arrived in Brazil and introduced domesticated chickens into the country. We identified at least two instances of ancestral chicken-to-human infections in ST353. The evolution of C. jejuni in Brazil was driven by the confluence of clinically relevant genetic elements, multi-host adaptation and clonal population growth that coincided with major socio-economic changes in poultry farming.
Assuntos
Campylobacter jejuni , Galinhas , Evolução Molecular , Genoma Bacteriano , Campylobacter jejuni/genética , Campylobacter jejuni/efeitos dos fármacos , Campylobacter jejuni/isolamento & purificação , Campylobacter jejuni/classificação , Brasil , Animais , Galinhas/microbiologia , Humanos , Infecções por Campylobacter/microbiologia , Infecções por Campylobacter/veterinária , Adaptação ao Hospedeiro/genética , Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , FilogeniaRESUMO
BACKGROUND: Antibiotic-producing Streptomyces bacteria are ubiquitous in nature, yet most studies of its diversity have focused on free-living strains inhabiting diverse soil environments and those in symbiotic relationship with invertebrates. RESULTS: We studied the draft genomes of 73 Streptomyces isolates sampled from the skin (wing and tail membranes) and fur surfaces of bats collected in Arizona and New Mexico. We uncovered large genomic variation and biosynthetic potential, even among closely related strains. The isolates, which were initially identified as three distinct species based on sequence variation in the 16S rRNA locus, could be distinguished as 41 different species based on genome-wide average nucleotide identity. Of the 32 biosynthetic gene cluster (BGC) classes detected, non-ribosomal peptide synthetases, siderophores, and terpenes were present in all genomes. On average, Streptomyces genomes carried 14 distinct classes of BGCs (range = 9-20). Results also revealed large inter- and intra-species variation in gene content (single nucleotide polymorphisms, accessory genes and singletons) and BGCs, further contributing to the overall genetic diversity present in bat-associated Streptomyces. Finally, we show that genome-wide recombination has partly contributed to the large genomic variation among strains of the same species. CONCLUSIONS: Our study provides an initial genomic assessment of bat-associated Streptomyces that will be critical to prioritizing those strains with the greatest ability to produce novel antibiotics. It also highlights the need to recognize within-species variation as an important factor in genetic manipulation studies, diversity estimates and drug discovery efforts in Streptomyces.
Assuntos
Quirópteros , Streptomyces , Animais , Arizona , Quirópteros/genética , Genômica , Família Multigênica , New Mexico , Filogenia , RNA Ribossômico 16S/genética , Streptomyces/genéticaRESUMO
nodA and nifH phylogenies for Cupriavidus nodule bacteria from native legumes in Texas and Costa Rica grouped all strains into a single clade nested among neotropical Burkholderia strains. Thus, Cupriavidus symbiotic genes were not acquired independently in different regions and are derived from other Betaproteobacteria rather than from alpha-rhizobial donors.