| Antibiotics are a class of compounds that can inhibit cell growth at trace concentrations.Sulfonamide antibiotics are the first synthetic antibiotics and are widely used in livestock and poultry breeding.The extensive use?abuse?of sulfanilamide antibiotics induces environmental microorganisms to produce sulfanilamide resistance genes and becomes a new environmental pollutant of great concern.There were significant differences in sulfonamide resistance genes in different environmental matrices.The lake formed by coal mining collapse is the characteristic water body of Huaibei.In this paper,the occurrence of seven typical sulfonamides?sulfanilamide,sulfadiazole,sulfathiazole,sulfapyridine,slulfamethazine,sulfamethoxazole and sulfadiazine?and their resistance genes?sul1,sul2,sul3 and sulA?and class one integrase genes?int1?in Nanhu water body of Yangzhuang coal mining subsidence area in Huaibei are investigated.The results are as follows:?1?Sulfanilamide,sulfadiazole,sulfathiazole,sulfapyridine,slulfamethazine,sulfamethoxazole and sulfadiazine were all detected in the water environment of south lake in huibei.In water samples,the detection frequencies of sulfadiazine,sulfadiazole,sulfadiazole,sulfadiazole,sulfadiazole and sulfadiazole were30%,10%,30%,90%and 70%,respectively,except sulfadiazine and sulfadiazine detected.Correspondingly,their average concentrations in water were 5.54ng·L-1,2.36 ng·L-1,7.87 ng·L-1,28.26 ng·L-1and 20.78 ng·L-1,respectively.The detection frequency and concentration of sulfamethoxazole were the highest in the sediment samples,which were 100%and 76.16 ng·L-1;followed by sulfadiazine.the detection frequency and concentration of which 40%and 30.29 ng·g-1,respectively.sulfadiazole was not detected.In general,the detection frequency and concentration of sulfanilamide antibiotics in sediment samples were higher than that in water samples.?2?The sulfanilamide resistance gene sul1?sul2 and a class of integrase genes int1 were PCR amplified from the samples of water and sediment in Nanhu Lake,Huaibei,but no sul3 and sulA of sulfanilamide resistance genes were detected in all samples.The detection frequency of sul1 genes in sediment is 100%,and its detection rate in water samples is 90%.The detection frequency of sul2 genes in sediment and water samples was lower than that of sul1,which was 80%.Similar to sul1,of class one integrase gene int1,the detection frequencies in sediment and water were 100%and 90%,respectively.?3?The abundance of sul1?sul2 and int1 genes in South Lake water samples varied significantly,the mean abudance of the 6.25×105 copy/mL?1×106 copy/mL and 1.12×106 copy/mL,respectively the same gene also has a large difference among different sampling points.The abundance of sul1 gene in water sample No.3is the highest,which is 1.50×105 copy/mL,while the abundance in water sample No.7 is lower than the detection limit.The abundance of sul2 genes was the highest in water sample No.1,2.64×106copy/mL.The abundance of int1 genes in water sample No.8 was the highest in water sample No.1,2.04×106 copy/mL and slightly lower than that in water sample No.8,2.26×106 copy/mL.Overall,the highest gene abundance in water sample No.1 was 5.29×106copy/ml,followed by water sample No.10 was 4.75×106 copy/mL,with the lowest total abundance in water sample No.2 1.30×106 copy/mL.The abundance of sul1?sul2 and int1 genes in sediment samples varied significantly,9.34×105copy/g,1.14×106copy/g and 1.3×106copy/g,respectively the highest gene abundance of sul1 in No.1 sediment sample was 3.06×106 copy/g,and the abundance in No.3 sediment sample was lower than the detection limit.The average abundance of sul2 genes is higher than that of sul1 genes.sul2highest gene abundance was found in sediment samples No.1?2.64×106 copy/g?,while sul2 abundance in sediment samples No.2 and No.10 was lower than the detection limit.The abundance of int1 genes was the highest in No.7 sediment samples,?3.79×106 copy/g?,while No.10 sediment samples has int1 slightly lower int1 abundance compared with that of No.7 sediment samples,3.01×106 copy/g.Overall,the highest gene abundance in sediment 1 was 6.36×106copy/g,followed by sediment 7,with the lowest total abundance in sediment 6.28×106 copy/g,No.8,1.26×106 copy/g.?4?The sulfanilamide resistant bacteria in the water samples of Nanhu Lake were much less than those in the sediment samples.The average of sulfonamide resistant bacteria in water is 8×101 cfu/mL;the maximum is 3.72×102 cfu/mL,the minimum is 3.0 cfu/ml;the average of sulfonamide resistant bacteria in sediment is 4.33×104cfu/g,the maximum is 1.21×105 cfu/g,the minimum is 5.0×103 cfu/g,the carrying rate of sul1 and sul2 of sulfonamides resistant bacteria isolated from aqueous samples was 75%,while the carrying rate of sulfonamides resistant bacteria sul1 and sul2 from sediment samples was lower than that of water samples,66.67%and 41.67%,respectively.This study is helpful to deepen the understanding of sulfonamide antibiotics and their resistance genes in coal mining collapse lakes in huaibei,and provides information for the development of environmental risk prediction and related blocking techniques. |
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