Evidence for Human Adaptation and Foodborne Transmission of Livestock-Associated Methicillin-Resistant Staphylococcus aureus.
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ABSTRACT:
SUBMITTER: Larsen J
PROVIDER: S-EPMC5091345 | biostudies-literature | 2016 Nov
REPOSITORIES: biostudies-literature
Publications
Evidence for Human Adaptation and Foodborne Transmission of Livestock-Associated Methicillin-Resistant Staphylococcus aureus.
Larsen Jesper J Stegger Marc M Andersen Paal S PS Petersen Andreas A Larsen Anders R AR Westh Henrik H Agersø Yvonne Y Fetsch Alexandra A Kraushaar Britta B Käsbohrer Annemarie A Feβler Andrea T AT Schwarz Stefan S Cuny Christiane C Witte Wolfgang W Butaye Patrick P Denis Olivier O Haenni Marisa M Madec Jean-Yves JY Jouy Eric E Laurent Frederic F Battisti Antonio A Franco Alessia A Alba Patricia P Mammina Caterina C Pantosti Annalisa A Monaco Monica M Wagenaar Jaap A JA de Boer Enne E van Duijkeren Engeline E Heck Max M Domínguez Lucas L Torres Carmen C Zarazaga Myriam M Price Lance B LB Skov Robert L RL
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 20160920 10
We investigated the evolution and epidemiology of a novel livestock-associated methicillin-resistant Staphylococcus aureus strain, which colonizes and infects urban-dwelling Danes even without a Danish animal reservoir. Genetic evidence suggests both poultry and human adaptation, with poultry meat implicated as a probable source. ...[more]
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Project description:Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) sequence type 9 (ST9) has emerged and disseminated in Asia. It is associated with colonization or infection in both humans and animal hosts; however, the genetic factors underpinning its adaptation to animal and human population remain to be determined. Here, we conducted a genomic analysis of 191 ST9 S. aureus genomes collected from 12 different countries, including 174 genomes retrieved from public databases and 17 sequenced in this study. In silico spa typing, staphylococcal cassette chromosome mec (SCCmec) typing, and antimicrobial resistance and virulence gene mining were conducted, and the temporal phylogenetic signal was assessed by Bayesian inference. Our results point toward a human methicillin-susceptible S. aureus (MSSA) origin of ST9 that evolved approximately 2 centuries ago. Three major genetic events occurred during ST9 host shift from human to animals: the loss of the immune evasion cluster genes (scn, chp, and sak), which were reported to contribute to virulence in human infections, the acquisition of the SaPIbov4-like element-encoding vwb gene, which is an animal-specific virulence factor responsible for the clotting of animal plasma, and the acquisition of antibiotic resistance genes, including SCCmec, quinolone resistance-determining region (QRDR) mutations, and a multidrug resistance genetic element (MDRST9). Evidence of direct transmission of animal-adapted strains to human hosts also suggest that transmission could potentially reshape the resistance and virulence genetic pool in these isolates. The rapid clonal expansion of MDR ST9 strains in mainland China and Taiwan highlights the increasing need for effective surveillance of antibiotic consumption in animal husbandry to control antimicrobial resistance spread. IMPORTANCE Staphylococcus aureus sequence type 9 (ST9) is the main LA-MRSA clone spreading in the Asian continent. It can colonize and cause mild to severe infections both in animal and humans. Previous work described its genotypic characteristics; however, the molecular history of global spread of ST9 strains remains largely unclear. We conducted a detailed analysis of genomic evolution of global ST9 strains and identified key genetic changes associated with its adaptation to specific hosts. Our results suggest that the ST9 clone originated from human-adapted strains, which lost genes related to the evasion of the immune system. The introduction of ST9 strains in animal populations was aligned with the acquisition of animal-specific virulent factors and mobile elements harboring multiple antimicrobial resistance genes, especially in isolates from mainland China and Taiwan.
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