Bacterial Diversity And Drug Resistance Of Marine Organism In Maoweihai Mangrove

Mangrove waters in Maoweihai of Qinzhou Bay are the key areas for the development of Beibu Bay in Guangxi,and aquaculture industry has developed rapidly.The abuse of antibiotics in aquaculture results in the generation of bacterial resistance and resistance genes in organisms and environment.Sulfonamide antibiotics are commonly used in mariculture.In this study,the bacterial diversity of marine animals,the distribution of sulfonamide-resistant bacteria and the carrying of sulfonamide-resistant genes in mangroves of Maowui Sea,Qinzhou Bay,Guangxi were studied.It provides a theoretical basis for the use of antibiotics in aquaculture and environmental protection.In this paper,seven common marine animals,such as shrimp and tiger fish,hunchback pepper sparrow,white-line bone scaled fish,short-sheathed octopus,pepper sparrow,black thorn sparrow and horseback sparrow,were captured in the mangrove area of Maoweihai.The bacteria in gill and intestinal tract were screened and isolated to study the diversity of bacteria from marine animals in Maoweihai mangrove.Bacteria from marine animals were isolated by plate coating method,purified by 2216 E solid medium,identified by agarose electrophoresis,sequenced and constructed the sequence development tree of main bacteria.In the end,110 strains of bacteria were isolated from gill and intestinal tract of seven marine animals,including Shiva,Dietzia and Streptomyces.The main bacteria isolated from gills and intestines of marine animal species were tested for their resistance to five sulfonamide antibiotics: sulfadiazine(SDZ),sulfamethoxazole(SMX),sulfathiazole(STZ),sulfamethazine(SMZ),trimethoprim(TMP).It was found that 12 of 110 strains of bacteria belonging to different genera had antibiotic resistance.Among them,Shiva,Dietzia,Agrococcus,Streptomyces,Psychrophiles,Microbacterium and Brevibacterium are more resistant to five sulfonamides.Especially for the most commonly used sulfamethazine,the average resistance rate was 54.3%,and the resistance rate of dominant strains was 100%.Compared with the resistance rate of bacteria in gills of different marine animals,the resistance rate of intestinal bacteria is higher.Sulfonamide resistance genes Sul I and sul II of marine animal-derived bacteria were accurately quantitatively analyzed by fluorescence quantitative analysis.The results showed that the total DNA of bacteria isolated from gills and intestines of different marine animals had a very high detection rate of Sul I and sul II sulfonamide resistance genes,and the detection rate maintained between 80% and 100%.The fluorescence quantitative results showed that Sul I and sul II were relatively abundant in all bacteria,indicating that the bacteria from mangrove marine animals in Maotai Sea had high resistance to sulfonamide antibiotics.