Isolation and Characterization of an Antibiotic‐producing Advenella Species

Abstract

Antibiotic resistance mechanisms in pathogenic bacteria paired with the general overuse of antibiotics has caused an exponential decrease in the efficiency of many antibiotics. To search for producers of novel antibiotics, this scientific research has turned to the most naturally abundant microbial source, soil. Specifically, the isolation and identification of antibiotic‐producing bacteria from a soil sample was the primary objective of this research. A soil sample collected in late January of 2019 from a mountain edge located at the Chalon campus of Mount Saint Mary’s University‐Los Angeles underwent serial dilutions and plating to isolate bacteria. Once isolated, the bacteria were screened against various ESKAPE relatives, and a viable producer against Bacillus subtilis was identified. The producer’s 16S rRNA gene was amplified through colony PCR, purified through gel electrophoresis, and sequenced. The gene sequence of the producer identified it as a lesser known soil microbe, Advenella kashmirensis (98.41%). Prior research has described Advenella kashmirensis as a sulfur‐oxidizing, chemolithotrophic, gram‐negative soil bacteria, but this bacteria species has not been previously linked to antibiotic production or pathogen inhibition. Therefore, research continued with repeated, successful screenings against B. subtilis, as well as with efforts to support the identification of the producer through the following biochemical tests: urease (positive), catalase (positive), nitrate (positive, reduction beyond nitrite), gelatin (negative), and citrate utilization (negative). Future work will involve further characterization of the isolate through additional biochemical testing as well as attempts to isolate and purify the antibiotic.