Study On Antibiotic And Heavy Metal Resistance Of Aeromonas Spp.in The Bahe River,China

Aeromonas is a kind of zoonosis bacteria which is widely found in nature,causing disease mainly by infecting host intestinal tract.As a kind of water-borne and food-borne pathogenic bacteria,it is easy to spread widely,which seriously threatens the public health and the development of breeding industry.At present,antibiotics are one of the main methods to prevent and treat Aeromonas.But Antibiotic resistance which caused by antibiotics abuse problem emerges,under the long-term effects of antibiotics,Antibiotic resistance genes(ARGs)in the environment and the bacteria screening and enriched constantly,causing bacteria resistant phenotype level rise.Bahe river,as one of the main rivers in xi?an city,is an important water source for surrounding human activities.To investigate the antibiotic resistance of Aeromonas Spp.isolated from Bahe river,Our research chooses the Aeromonas spp.isolated from Bahe river and water sample of Bahe river as the research object,take samples in June 2018 and August 2019,determining the level of antibiotics,heavy metals and the physical and chemical factors in the Bahe river;And detected the antibiotic and heavy metal resistance phenotype of Aeromonas.Some representative Aeromonas strains and resistance genes were selected.PCR amplification was used to qualitative detect antibiotic resistance genes(bla TEM,bla SHV,blactx-m,bla IMP,bla OXA etc.)and heavy metal resistance genes(czc A,cop A,mer A,chr R),the results are as follows:(1)The result shows that the middle and lower reaches of Bahe river(S2,S3 and S4)pollution is more serious than the upstream(S1),heavy metals and antibiotics contents in the middle and lower reaches of Bahe river is higher than the upstream(S1).(2)In the two samples,the heavy metal resistance phenotype was relatively stable,the minimum inhibitory concentration(MIC)of Aeromonas to the same heavy metal,but at different sampling sites and sampling times had a relatively fixed value.Most of Aeromonas bacteria are highly resistant to cephalosporin and melopenem,and are sensitive to chloramphenicol and quinolones.(3)In 29 kinds of resistance genes,26 of them were detected,only bla OXA,bla IMP and qnr B were not detected in all strains.4 kinds of heavy metal resistace genes were detected,bla TEM had the highest detection rate in all resistance genes,this indicates that Aeromonas is the reservoir of some resistance genes in the environment,and Aeromonas hydrophila detected high proportion and many kinds of antibiotic and heavy metal resistance genes,is the main transmitter of drug resistance genes.(4)The distribution of drug resistance genes in different bacteria species and different sampling sites is different.Because of the environmental conditions at different sampling sites or the change of bacteria species,which leads to the different distribution of drug resistance genes.The pollution of environmental physical and chemical factors will lead to the increase of bacterial drug resistance genes in water,causing the aggravation of bacterial drug resistance.