Microplastics in agriculture – a potential novel mechanism for the delivery of human pathogens onto crops

Mulching with plastic sheeting, the use of plastic carriers in seed coatings, and irrigation with wastewater or contaminated surface water have resulted in plastics, and microplastics, becoming ubiquitous in agricultural soils. Once in the environment, plastic surfaces quickly become colonised by microbial biofilm comprised of a diverse microbial community. This so-called ‘plastisphere’ community can also include human pathogens, particularly if the plastic has been exposed to faecal contamination (e.g., from wastewater or organic manures and livestock faeces). The plastisphere is hypothesised to facilitate the survival and dissemination of pathogens, and therefore plastics in agricultural systems could play a significant role in transferring human pathogens to crops, particularly as microplastics adhering to ready to eat crops are difficult to remove by washing. In this paper we critically discuss the pathways for human pathogens associated with microplastics to interact with crop leaves and roots, and the potential for the transfer, adherence, and uptake of human pathogens from the plastisphere to plants. Globally, the concentration of plastics in agricultural soils are increasing, therefore, quantifying the potential for the plastisphere to transfer human pathogens into the food chain needs to be treated as a priority

Comparison of Bioavailability Between the Most Available Generic Tablet Formulation Containing Artemether and Lumefantrine on the Tanzanian Market and the Innovator's Product.

Existence of anti-malarial generic drugs with low bioavailability marketed on sub-Saharan Africa has raised a concern on patients achieving therapeutic concentrations after intake of these products. This work compared bioavailability of one generic tablet formulation with innovator's product. Both were fixed dose combination tablet formulations containing artemether and lumefantrine.MethodologyThe study was conducted in Dar Es Salaam, Tanzania, in which a survey of the most abundant generic containing artemether-lumefantrine tablet formulation was carried out in retail pharmacies. The most widely available generic (Artefan(R), Ajanta Pharma Ltd, Maharashtra, India) was sampled for bioavailability comparison with Coartem(R) (Novartis Pharma, Basel, Switzerland) - the innovator's product. A randomized, two-treatment cross-over study was conducted in 18 healthy Tanzanian black male volunteers. Each volunteer received Artefan(R) (test) and Coartem(R) (as reference) formulation separated by 42 days of drug-free washout period. Serial blood samples were collected up to 168 hours after oral administration of a single dose of each treatment. Quantitation of lumefantrine plasma levels was done using HPLC with UV detection. Bioequivalence of the two products was assessed in accordance with the US Food and Drug Authority (FDA) guidelines. The most widely available generic in pharmacies was Artefan(R) from India. All eighteen enrolled volunteers completed the study and both test and reference tablet formulations were well tolerated. It was possible to quantify lumefantrine alone, therefore, the pharmacokinetic parameters reported herein are for lumefantrine. The geometric mean ratios for Cmax, AUC0-t and AUC0-[infinity] were 84% in all cases and within FDA recommended bioequivalence limits of 80% -- 125%, but the 90% confidence intervals were outside FDA recommended limits (CI 49--143%, 53 - 137%, 52 - 135% respectively). There were no statistical significant differences between the two formulations with regard to PK parameters (P > 0.05). Although the ratios of AUCs and Cmax were within the acceptable FDA range, bioequivalence between Artefan(R) and Coartem(R) tablet formulations was not demonstrated due to failure to comply with the FDA 90 % confidence interval criteria. Based on the observed total drug exposure (AUCs), Artefan(R) is likely to produce a similar therapeutic response as Coartem(R)