Emergence of human-adapted Salmonella enterica is linked to the Neolithization process

Abstract

It has been hypothesized that the Neolithic transition towards an agricultural and pastoralist economy facilitated the emergence of human adapted pathogens. Here, we recovered eight Salmonella enterica subsp. enterica genomes from human skeletons of transitional foragers, pastoralists, and agro-pastoralists in western Eurasia that were up to 6,500 years old. Despite the high genetic diversity of S. enterica all ancient bacterial genomes clustered in a single previously uncharacterized branch that contains S. enterica adapted to multiple mammalian species. All ancient bacterial genomes from prehistoric (agro-)pastoralists fall within a part of this branch that also includes the human-specific S. enterica Paratyphi C, illustrating the evolution of a human pathogen over a period of five thousand years. Bacterial genomic comparisons suggest that the earlier ancient strains were not host specific, differed in pathogenic potential, and experienced convergent pseudogenization that accompanied their downstream host adaptation. These observations support the concept that the emergence of human adapted S. enterica is linked to human cultural transformations.

Diet and subsistence in Bronze Age pastoral communities from the southern Russian steppes and the North Caucasus

“…Some of these graves contained bones of domesticated animals, whereas most bone artifacts represent wild species [20,18]. Despite the evidence for domesticated animals, it is still unclear whether the communities who erected the earliest mounds in the southern Russian steppe represent the first pastoralists or late hunter-gatherers [42,43].…”

The Recovery, Interpretation and Use of Ancient Pathogen Genomes

“…For these pathogens, acquiring ancient DNA requires soft-tissue samples, faecal remains, gut-associated sediment samples or archival medical or histologically preserved samples [57]. In exceptional cases, enteric pathogens can become blood borne, which might explain the recovery of Salmonella enterica serovar Paratyphi C (causing bacterial enteric fever) from teeth of victims from a 16 th century Mesoamerican epidemic [18,58] as well as from 13 th century Norway [11,19]. Hematogenous infections, such as bubonic plague, are more likely to be detectable in the blood-fed root or pulp cavity of teeth than in bones.…”

A Significant Question in Cancer Risk and Therapy: Are Antibiotics Positive or Negative Effectors? Current Answers and Possible Alternatives

“…Data derived from paleomicrobiology along with written historical records have clearly shown that, at times, certain pathogenic bacteria spread at high rates and their transmission acquired epidemic or even pandemic proportions (Table 1). However, it has become also clear that the progression of human civilization to more sedentary ways of life (e.g., the transition from hunter-gatherer communities to societies with agriculturalist and pastoralist economies) followed by the creation of ever larger cities and the establishment of better ways of communication between cities allowed the appearance of sustained infections by human-adapted bacterial pathogens [56,57], many of which were of zoonotic origin, transmitted from animals in various ways [58][59][60]. Information about the treatment of bacterial infections through the early years of the 20th century has been recorded in writings from ancient Greece, where Hippocrates became the founder of modern medicine [61,62].…”