Ecological Populations of Bacteria Act as Socially Cohesive Units of Antibiotic Production and Resistance

Abstract

In animals and plants, social structure can reduce conflict within populations and bias aggression toward competing populations; however, for bacteria in the wild it remains unknown whether such population-level organization exists. Here, we show that environmental bacteria are organized into socially cohesive units in which antagonism occurs between rather than within ecologically defined populations. By screening approximately 35,000 possible mutual interactions among Vibrionaceae isolates from the ocean, we show that genotypic clusters known to have cohesive habitat association also act as units in terms of antibiotic production and resistance. Genetic analyses show that within populations, broad-range antibiotics are produced by few genotypes, whereas all others are resistant, suggesting cooperation between conspecifics. Natural antibiotics may thus mediate competition between populations rather than solely increase the success of individuals.

Intensive aquaculture selects for increased virulence and interference competition in bacteria

“…The strains isolated from outlet water seemed to be able to inhibit the growth of the inlet water strains but tolerated well the toxins produced by other outlet water strains, probably due to more homogeneous population structure resulting in less competitive interactions [61]. While these results are in accordance with the general expectations of the evolution of interference competition in mixed populations [54,57], whether these interactions are relevant during disease outbreaks is unknown, and type I error in the interpretation of the results is possible. Nevertheless, different bacterial population structure was observed in these two locations even during the same sampling dates that are directly comparable (table 2).…”

“…Strain-strain interactions can have a significant role in bacterial disease dynamics via competition in both within-host and outside-host environments [54][55][56][57][58], and the surrounding microbial community has been shown to have significant effects on the evolution of interference [59,60]. However, how interference competition is associated with intensive farming is not properly understood.…”

Teleological reasoning about nature: intentional design or relational perspectives?

“…In fact, biologists argue that both human and non-human animals inhabit complex social and mental worlds, and intra-and interspecies cooperative strategies are critical to mutual adaptation and survival [60][61][62][63][64]. Moreover, animals' participation in cooperative socio-ecological systems means that 'other-serving functions' aid own survival.…”

Functional response of the fungus Hirsutella rhossiliensis to the nematode, Heterodera glycines

“…Social structure has been revealed even among bacteria [40], and it has been inferred that cohesive population-level social organization similar to animal and plant populations may also exist among microorganisms. In the case of filamentous fungi, although such findings have not yet been reported, we believe as a more complicated species compared with bacteria, filamentous fungi should also exhibit reasonable social structure and behavioral attributes.…”