A Multiple Antibiotic-Resistant <i>Enterobacter cloacae</i> Strain Isolated from a Bioethanol Fermentation Facility

Abstract

An Enterobacter cloacae strain (E. cloacae F3S3) that was collected as part of a project to assess antibiotic resistance among bacteria isolated from bioethanol fermentation facilities demonstrated high levels of resistance to antibiotics added prophylactically to bioethanol fermentors. PCR assays revealed the presence of canonical genes encoding resistance to penicillin (ampC) and erythromycin (ermG). Assays measuring biofilm formation under antibiotic stress indicated that erythromycin induced biofilm formation in E. cloacae F3S3. Planktonic growth and biofilm formation were observed at a high ethanol content, indicating E. cloacae F3S3 can persist in a bioethanol fermentor under the highly variable environmental conditions found in fermentors.

Survivability of Microbes in Natural Environments and Their Ecological Impacts

“…A recent review article proposed that limited diversity of ammonia oxidizers in soil may essentially determine stability of N-cycling functions within the ecosystem ( 12 ). In biotechnological fields, stress response and survivability of microbes are recognized as key factors relevant to the ability to maintain the functional stability of bioreactors ( 16 , 29 ). It is noteworthy that a recent metagenomic study on composting processes revealed the abundance of genes related to stress responses ( 25 ).…”