Antibiotic Uptake by Plants from Soil Fertilized with Animal Manure K.Kumar, S.c. Gupta, SK.Baidoo,Y.Chander,and C.J.Rosen Presented by Ju Hwan Oh Soil Science Lab. Published in J. Environ. Qual 34:2082-2085 (2005) Antibiotics? Tylosin Chlortetracycline Antibiotics are compounds produced by various living organisms, such as yeast or fungi. Treating infectious diseases (human, animal) feces and urine Common antibiotics tetracyclines (oxatetracycline and chlortetracycline) tylosin sulfamethazine amprolium menensin virginiamycin penicillin nicarbazine (Webb and Fontenot, 1975; De Liguoro et al., 2003;Kumar et al., 2004, 2005) Absorption of antibiotics in the animal gut is not complete and as a result substantial amounts of antibiotics are excreted in urine and feces that end up in manure. Manure is used worldwide not only as a source of plant nutrients but also as a source of organic matter to improve soil quality especially in organic and sustainable agriculture. Manure applied as raw manure (fresh or dried) or composted, no guidelines on the presence of contaminants such as hormone and antibiotics. Action of tetracycline ? Tetracyclines are broad - spectrum bacteriostatic agents and act by inhibiting protein synthesis by blocking the binding of aminoacyl tRNA (transfer RNA) to the mRNA(messenger RNA) ribosome complex. Antiacne agent (topical) - probably due to their antibacterial activity. Topical tetracyclines are thought to suppress the growth of propionibacterium acnes, an anaerobe found in sebaceous glands and follicles. P. acnes produces proteases hyaluronidases, lipases, and chemotactic factors, alI of which can produce inflammatory components or inflammation directly. The objective of the study To evaluate whether or not plants take up antibiotics from manure-soil mixtures, and if so to what extent? Materials and methods Experiment 1: Plant Uptake of Antibiotics from Soil spiked with Antibiotic 1. Soil : Hubbard loamy sand soil 2. Crop : Green onion(4/pot) and Cabbage(2/pot) 3. Added 50ml each of chlortetracycline and tylosin (20ug L-1 conc.). 4. Watered with 100ml of water twice a week and harvested at 3 and 6 wk after transplanting. 5. Fresh plant material grounding and extraction. 6. Antibiotics analyzed on the same day Materials and methods Experiment 2: Plant Uptake of Antibiotics from Manure-Applied Soils 1. Treatment – i) control ii) with antibiotics (100g chlortetracycline, 100g sulfamethazine, and 50g penicillin per ton feed) 2. At last week, manure collected 3. Treatments in the uptake study i) C-M (control manure) and Ab-M (antibiotic manure) ii) C-M + antibiotic and Ab-M + antibiotics (additional 100mg of chlortetracycline and tylosin per kg of dry manure) iii) Crop : corn, green onion and cabbage 4. Manure : 200 kg N ha-1 5. Antibiotic analysis in plant : ELISA method ( Kumar et al., 2004 ) Results and discussion Table 1. Concentration of antibiotics in plant tissues after 3 and 6 wk. Green onion Antibiotic 3 wk 6wk Cabbage 3 wk 6wk --------------- ng g-1 fresh weight --------------Tylosin ND* ND ND ND Chlortetracycline 14.4±2.3 12.8±1.7 11.4±2.1 10.0±1.8 *Not detected Results and discussion Table 2. Amount of antibiotics present per pot in various treatment Treatment* Chlortetracycline Tyrosin ---------- ug pot-1 ---------C-M 0 0 C-M + antibiotics 1000 1000 Ab-M 587 0 Ab-M + antibiotics 1587 1000 * See “Experiment 2” section of Materials and Methods for treatment descriptions. Results and discussion Table 3. Mean amount of chlortetracycline recovered in plant tops in various treatment.* Recovery C-M Ab-M C-M + Ab-M + antibiotics antibiotics ------------------ % -----------------Green onion 0 0.34 0.30 0.21 Cabbage 0 0.64 0.80 0.62 Corn 0 1.04 1.02 0.80 * See “Experiment 2” section of Materials and Methods for treatment descriptions. Chlortetracycline concentration (ng g-1 fresh soil) Results and discussion Chlortetracycline ( ug pot-1) Figure 1. Concentration of chlortetracycline in plant tops in relation to the amount of chlortetracycline present in the soil-manure mixture in a pot. Results and discussion Table 4. Characteristics of chlortetracycline and tylosin antibiotics. Antibiotic (class) Mass Water solubility* Log Kow** ------------- mg L-1 ------------Chlortetracycline (tetracyclines) 479 230 to 52000 -1.3 to 0.05 Tylosin (macrolides) 916 0.45 to 15 1.6 to 3.1 *Range provided for the whole class of antibiotics. ** Octanol-water partition coefficient Conclusion The adverse impacts of ingesting antibiotics present in plants by humans are not known at this stage. A few adverse impacts of consuming antibiotics in fresh vegetables (sweet corn) and friuts are speculated : - Alleric or toxic ( Patterson et al., 1995 and Basaraba et al., 1999) - Antibiotic resistance ( Selim and Cullor, 1997; Langford et al., 2003) Further study There is an urgent need study i) The fate of different antibiotic present in manure ii) which antibiotics and their degradation products may be taken up by plants iii) whether or not antibiotics present in food degrade when cooked iv) whether or not antibiotics or their degradation products are bioactive to impart antibiotic resistance to gut bacteria or cause adverse immunological reaction in humans.