Effect of antibiotics in the environment on microbial populations

Abstract

Antibiotics act as an ecological factor in the environment that could potentially affect microbial communities. The effects include phylogenetic structure alteration, resistance expansion, and ecological function disturbance in the micro-ecosystem. Numerous studies have detected changes of microbial community structure upon addition of antibiotics in soil and water environment. However, the causal relationship between antibiotic input and resistance expansion is still under debate, with evidence either supporting or declining the contribution of antibiotics on alteration of antibiotic resistance. Effects of antibiotics on ecological functions have also been discovered, including nitrogen transformation, methanogenesis, and sulfate reduction. In the latter part, this review discusses in detail on factors that influence antibiotic effects on microbial communities in soil and aquatic environment, including concentration of antibiotics, exposure time, added substrates, as well as combined effects of multiple antibiotics. In all, recent research progress offer an outline of effects of antibiotics in the natural environment. However, questions raised in this review need further investigation in order to provide a comprehensive risk assessment on the consequence of anthropogenic antibiotic input.

Incidences and antimicrobial susceptibility profile of Staphylococcus species isolated from animals in different Qatari farms

“…Some bacteria have developed resistances to all of the different classes of antibiotics discovered up to date, and the most frequent type of resistance is acquired and transmitted horizontally via mobile genetic elements such as plasmids, transposons and integrons (Tiemersma et al, 2004). The improper antibacterial treatment and overuse of antibiotics for agricultural purposes have contributed to the increased incidence of multiple antibiotic resistances in farm animals (Shryock and Richwine, 2010;Ding and He, 2010).…”

Changes in functional diversity of soil microbial community with addition of antibiotics sulfamethoxazole and chlortetracycline

“…Antibiotic addition can change soil microbial community structure and increase bacterial antibiotic resistance, which have been investigated in a number of studies by molecular profiling or similar methods such as denaturing gradient gel electrophoresis (DGGE), phospholipids fatty acid analysis (PLFA), terminal restriction fragment length polymorphism (T-RFLP), and quantitative real-time PCR (qPCR) (Hammesfahr et al 2008;Heuer and Smalla 2007;Muller et al 2002;Naslund et al 2008;Schauss et al 2009). However, till now, researches about antibiotic effects on soil ecological functions are still limited (Ding and He 2010).…”

Understanding the contribution of environmental factors in the spread of antimicrobial resistance

“…Soil inevitably becomes a hot spot for antibiotics to affect indigenous microbes. Additionally, genetic exchange is encouraged by the higher density of microbes in the soil environment, contributing to the development of microbial resistance in the presence of antibiotics [45]. Bacterial resistant genes adapted to soil or other habitats can be transferred horizontally, resulting in independent transmission further into the environment [46].…”

“…Nonpathogenic bacteria in this environment can act as a reservoir of resistance genes and platforms [39,45,54]. With the progressive accumulation of antimicrobial agents, detergents, disinfectants, and residues from industrial pollution, as heavy metals introduced into the environment, the evolution and spread of such resistant organisms in the water environment is facilitated [55].…”