Antibiotic Resistance Case Study

The development of increased resistance to antibiotics is a global concern. According to WHO (2015), antimicrobial resistance is an increasingly serious threat to global public health that requires action across all government sectors and society. Antibiotic resistance threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria, thereby resulting to loss of the ability to treat common infections.
The development of antibiotic resistance is a natural phenomenon but can be accelerated by anthropogenic activities. The inappropriate use of antibacterial drugs in humans and their use in animal husbandry (resulting to their release into the evironment), favours the emergence and selection of resistant
Agro-waste materials such as sugar bagasse, rice/maize husks among others are readily available. Biochar with its high sorptive capacity due to high specific surface area and microporosity (Hunt et al., 2010) effectively increases the immobilization of pollutants in soil and has already been proposed as manure additive to improve the nutrient status. It is hypothesized that admixtures of biochar to manure additionally (1) reduce the mobility and bioavailability of antibiotics in manure and subsequently in soil, and (2) increase sessile bacteria and retard mobile genetic elements. In either case admixtures of biochar to manure will reduce the resistance gene exchange and resistance level in manure and soil. This will be tested in batch and 3-month incubation experiments on the sorption and mobility of antibiotics (sulfonamides, tetracyclines) spiked to biochar from agro-waste materials, arable topsoil and pig slurry, and mixtures thereof. Sorption isotherms, kinetics and mechanisms will be derived from this. The distribution and abundance of tetracycline and sulfonamide resistance genes will be determined in the time-resolved experiments using qPCR and effects on the structural diversity of the soil microbial community will be determined by analyses of PLFA and 16S rRNA gene
To lower the mobility and increase the immobilization of pollutants in soil, the amendment of soil with biochar has been proven as an efficient technique (Yadanaparthi et al., 2009). Biochar is produced through pyrolysis of biomass resulting in substrates of low degradability and high sorptive capacity due to high specific surface area and microporosity (Preston & Schmidt, 2006; Hunt et al., 2010), whose properties vary depending on the preparation conditions (Zheng et al., 2013). Enhanced sorption of diverse pharmaceutical antibiotics such as fluoroquinolones, sulfonamides, tylosin, and tetracyclines in soils amended with biochar from different sources has been demonstrated (Pan et al., 2012; Teixidó et al., 2011; Wu et al., 2013; Han et al. 2013). Related sorption mechanisms have been attributed to charge-assisted H-bonds, hydrophobic interaction, π-π electron donor-acceptor interaction and micropore-filling and electrostatic repulsion (Ji et al., 2011; Teixidó et al., 2011; Wu et al., 2013; Zheng et al., 2013). Additionally, biochar indirectly increases the sorption of organic pollutants in soil, since the retardation and sequestration