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Isolation and Screening of Antibiotic‐Producing Bacillus and Pseudomonas Species
Author(s) -
Carrera Esmeralda,
Peterson Stacey N.
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2020.34.s1.00550
Subject(s) - antibiotics , bacteria , microbiology and biotechnology , biology , pseudomonas , bacillus (shape) , bacillus subtilis , antibiotic resistance , genetics
Antibiotic resistance is a major problem in the world today and contributes to many deaths each year, particularly in the immunocompromised. Bacteria use several mechanisms to avoid inhibition and destruction by antibiotics including the formation of biofilms, inactivating the drug, and preventing the antibiotic from reaching its target. Since many antibiotics are no longer effective against certain bacteria, there is a need to find new antibiotics that can inhibit the growth of these bacteria. Many antibiotics currently used have originated from bacteria that live in the soil. The purpose of this project was to isolate bacteria from soil samples collected from Mount Saint Mary’s University and screen them against a variety of bacteria to identify antibiotic‐producers. Ultimately the producers will be further characterized and the antibiotics isolated and identified. Four antibiotic producers were identified whose 16S rRNA genes were amplified by PCR and sent out for sequencing. The producers were identified as gram‐positive Bacillus megaterium and various gram‐negative Pseudomonas species. These bacteria were able to inhibit the growth of Bacillus subtilis and Erwinia carotovora . The Pseudomonas species were chosen for further analysis and isolation of the antibiotics. An ethyl acetate extraction was performed as a first step in isolating the antibiotic from one species most closely related to P. koreensis . The suspected antibiotic was recovered from the organic layer as determined by its activity against B. subtilis . The antibiotic extract was quantified and purified through HPLC. Additionally, biochemical tests such as the citrate utilization test and gelatin hydrolysis test were done to provide more information on the characteristics of the Pseudomonas producers. The biochemical tests showed that producers such as P. koreensis were able to use citrate as a carbon source and produce gelatinase. Ultimately the goal of this research is to identify new antibiotic sources with the long‐term goal of isolating and identifying a new antibiotic.