...

Antibiotics?

by user

on
5

views

Report

Comments

Transcript

Antibiotics?
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.
Fly UP