Soil microbial response to tetracycline in two different soils amended with cow manure

Abstract

High amounts of antibiotics are introduced in the soil environment by manure amendment, which is the most important spreading route in soil, with a potential ecotoxicological impact on the environment. The objectives of this study were (a) to assess the tetracycline (Tc) bioavailability in a clay and in a sandy soil, and (b) to evaluate the effects of the Tc and cow manure on the structure and function of soil microbial communities. Clay and sandy soils were spiked with Tc at the concentrations of 100 and 500 mg Tc kg(-1) soil, and were amended or not with cow manure. The clay soil showed greater Tc sorption capacity and bioavailable Tc was between 0.157 and 4.602 mg kg(-1) soil. Tc dose and time-dependent effects on soil microbial communities were investigated by fluorescein diacetate activity, phospholipid fatty acids analysis, as well as by Biolog community level physiological profile and microbial counts at 2, 7 and 60 days after Tc and/or manure addition. The added Tc caused detrimental effect on the microbial activity and structure, particularly in the short term at the highest concentrations. However, the Tc effect was transient' it decreased after 7 days and totally disappeared within 60 days. Cow manure shifted the bacterial structure in both soils, increased the microbial activity in clay soil and contributed to recover the microbial structure in Tc-spiked manure treatments.

Fate of tetracycline antibiotics in dairy manure-amended soils

“…Though research frequently focuses on the introduction of pathogenic microbes to the environment from animal manure (Salgado et al 2011), data indicate that manure application is directly associated with increasing numbers of antibiotic-resistant bacteria in soil (Sengeløv et al 2003;Peng et al 2014). Residual antibiotics in land-applied manure exert a selective pressure on resident soil microbes, causing a shift in the microbial community toward more resistant microorganisms (Boxall et al 2003;Pruden et al 2006;Chessa et al 2016). Recent studies show that very low antibiotic concentrations in the environment can induce selection for resistance (Gullberg et al 2011;Liu et al 2011).…”

Peer Review #2 of "Improvement of subsoil physicochemical and microbial properties by short-term fallow practices (v0.1)"

“…More genera showed significant differences in June than in August and October. Therefore, we found that fertilization and vegetation can change some microbial communities in a short period of time (Chessa et al 2016;. Then, a legacy effect can adjust the microbial composition (Elgersma et al 2011).…”

Functional Diversity of Soil Microbial Communities in Response to the Application of Cefuroxime and/or Antibiotic-Resistant Pseudomonas putida Strain MC1

“…This could result in an increase in the number of degrading microorganisms and therefore, an increase in enzyme production. Alternatively, the negative effect of XM could have been masked by the increased activity of other microorganisms capable of surviving in the presence of an antibiotic and/or using compounds released from the cells of killed microorganisms [9,64,65]. The effect observed could also be related to the XM degradation in the soil.…”