STUDY OF TOXICITY OF VETERINARY DRUG- ENROFLAXACIN ON ORGANISMS ISOLATED FROM DRUG AFFECTED SOIL AND ITS DEGRADATION (original) (raw)

Enroflaxacin(EFX) is one of the most frequently used broad-spectrum synthetic quinolones veterinary drugs and its concentration ranges from 0.3 to 142mg/kg in manure. The misuse/ overuse of antibiotics release residues in various environment, such as soil, agricultural farms, waste water treatment plants, lakes, rivers and ground water. Samples were collected from the veterinary hospital of Valsad district and Pardi (drug affected area). Isolation was performed using Thiosulfate citrate bile salts sucrose medium and Sabourauds medium, 12 isolates of bacteria (YS-1, GM-1, BS, YM, YNL, YS-2, GM-2, GNS, G-1, G-2, GNL and OS) and 3 isolates of fungi (FY, FB, FG) were obtained. These isolates were exposed to three different concentration (5,25,70mmol) of 50 and 150 mg of EFX each to check their tolerance. From which 11 isolates of bacteria were susceptible and 1 isolated bacteria(YM-1) and 3 fungi(FG, FB, FY) were resistant. Field test was performed to check the effect of higher concentration of EFX on isolate YM-1 and all three fungi in soil collected from drug affected area which are able to tolerate the known amount of EFX in bioassay. After 4 days at 200 mmol concentration of EFX no growth of bacteria was observed by SPC but all the three fungi are able to tolerate this concentration of EFX. As no growth was observed in field test at 200mmole concentration, this concentration was exposed to Physical and Biological degradation. Physical degradation was performed using Ultraviolet rays at different interval of time from 1min,…,21min and the smallest zone size of 38mm with strain GM-1 was observed at 21minutes, which shows degradation of EFX after 21 minutes of exposure. Biological degradation of EFX was performed using all 3 isolated fungi in Sabourauds medium and consideration amount of breakdown of EFX was obtain using chemical oxygen demand(COD) colorimetric method. The fungi FB was able to degrade more amount of EFX after exposure for 15 days. OD was measured at 420nm at an interval of 5 days. TLC was performed to check the degraded EFX and the Rf value of degraded EFX was 0.05 and that of standard EFX was 0.7. The fungi FB which can degrade higher amount of EFX in biological method, was identified to be related to Aspergillus niger DTO 370-I7 by molecular identification. IndexTerms-Enroflaxacin, Quinolones, antibiotic, Thiosulfate citrate bile salt, Degradation. INTRODUCTION Since, their first discovery, antibiotics have played incomparable roles in treatment of diseases and promotion of animal feed efficiency. There were more than 70 billion clinical doses of this antibiotics employed globally in 2010, and 162,00 tons of antibiotics were used in china in 2013 making upto 52% of veterinary drugs. Enroflaxacin (EFX) is one of the most frequently used broad-spectrum synthetic quinolones veterinary drugs and its concentration could range from 0.3 to 1,421mg/kg in manure. Fluoroquinolones constitute one of the largest groups of antibacterial pharmaceuticals used worldwide. They are relatively new group of synthetic antimicrobial agents derived from 3-quinolone carboxylic acid. The predecessor of the class was non-fluorinated nalidixic aid with a narrow spectrum of activity that was mainly limited to treating urinary tract infections. The spectrum of antibacterial activity was considerably enhanced by introducing a fluorine atom on the number 6-carbon atom. The new 6-fluoroquinolones chemotherapeutics have become very useful in a variety of infections, especially caused by pathogens resistant to older antibiotics. Excretion of these antibiotics and improper waste disposal has led to substantial concentrations of these compounds. Even the processing of communal wastewater in sewage-treatment plants cannot prevent entry of antibiotics into surface water because of their stability. Possible effects of antibiotics include both toxicity and the emergence of bacterial resistance to the antibiotics. Although the transformation of enrofloxacin by fungi has not been reported, cultures of wood-decaying fungi have been shown to convert Enroflaxacin to CO2 and several other metabolites. The fungi transforms enroflaxacin to enroflaxacin N-oxide, desethylene-enroflaxacin, and N-acetyliprofloxacin. The misuse or overuse of antibiotics results in their residues in various environment, such as soils, agricultural farms, waste water treatment plants, lakes, rivers and ground water. This calls the attention to the problematic of the environmental release of these compounds and to the effects that they may exert in the environment, highlighting the need of developing efficient treatment strategies for their removal and for restoring ecosystems impacted by this type of pollution.