Effects of antibiotics on isolation and culture of microorganisms from special habitats in Xinjiang of China

Abstract:

[Background] The special habitats of Lop Nur and Wensu Canyon in Xinjiang of China, with their special geographical location, extreme surrounding natural ecological environment, and less influence of human activities, promote their unique high-quality microbial resources. [Objective] To explore the effect of adding antibiotics on the selective isolation and culture of microorganisms and optimize the selective isolation and culture of microorganisms in special habitats of Xinjiang to reduce the repeated isolation of strains. In addition, more microorganisms tolerant to such antibiotics could be selectively cultured to discover more bioactive products. [Methods] With Gauze’s No.1 medium as the foundation medium, different concentrations of β-lactam antibiotic amoxicillin, aminoglycoside antibiotic kanamycin, ansa macrolide antibiotic rifampin, quinolone antibiotic norfloxacin, aminool antibiotic chloramphenicol, and aminoglycoside antibiotic streptomycin were added. Microorganisms from soil samples of Lop Nur and Wensu Canyon in Xinjiang were isolated. [Results] The species and number of microorganisms isolated by norfloxacin were the highest, followed by kanamycin, amoxicillin, rifampicin, and chloramphenicol. Most antibiotics were best separated by 1/10 MIC and 1/15 MIC concentration. Nineteen strains were isolated and distributed in 8 genera. Among them, 6 strains belonged to Bacillus, 5 strains belonged to Streptomyces, 3 strains belonged to Paenibacillus, 1 strain belonged to Rhizobium, 1 strain belonged to Metabacillus, 1 strain belonged to Promicromonospora, 1 strain belonged to Pontibacter, and 1 strain belonged to Nonomuraea. Five new species were isolated. Seventy-three strains were isolated from the soil samples of Wensu Canyon and distributed in 27 genera. Among them, 33 strains belonged to Streptomyces, 1 strain belonged to Sphingomonas, 2 strains belonged to Pseudoxanthomonas, 5 strains belonged to Pseudonocardia, 1 strain belonged to Pseudarthrobacter, 2 strains belonged to Promicromonospora, 1 strain belonged to Priestia, 1 strain belonged to Plantactinospora, 1 strain belonged to Paracoccus, 2 strains belonged to Paenibacillus, 2 strains belonged to Paenarthrobacter, 1 strain belonged to Nocardia, 1 strain belonged to Micromonospora, 1 strain belonged to Methylorubrum, 1 strain belonged to Methylobacterium, 5 strains belonged to Metabacillus, 1 strain belonged to Lentzea, 2 strains belonged to Kribbella, 1 strain belonged to Isoptericola, 1 strain belonged to Ensifer, 1 strain belonged to Bosea, 1 strain belonged to Arthrobacter, 2 strains belonged to Agromyces, 1 strain belonged to Agrococcus, 1 strain belonged to Actinokineospora, 1 strain belonged to Actinoalloteichus, and 1 strain belonged to Bacillus. Fourteen new species were isolated. [Conclusion] The addition of norfloxacin and kanamycin is beneficial to the selective isolation and culture of microorganisms and the discovery of new strains. This study provides guidance for the selective isolation and culture of rare microorganisms in special environments.

Key words:antibiotics;special habitats;selective isolation