Isolation of indigenous wastewater bacterial strains capable of mobilizing plasmid pBR325

Area of Science:

• Microbiology
• Environmental Science
• Genetics

Background:

• Enterobacteriaceae are common in wastewater environments.
• Antibiotic resistance is a growing public health concern.
• Plasmids can mediate the transfer of antibiotic resistance.

Purpose of the Study:

• To investigate antibiotic resistance transfer among Enterobacteriaceae from raw wastewater.
• To characterize the plasmid content and transfer capabilities of these bacteria.
• To assess the mobilization of laboratory plasmids by environmental isolates.

Main Methods:

• Isolation and identification of Enterobacteriaceae from raw wastewater.
• Plasmid profiling and antibiotic resistance characterization.
• Conjugation experiments to assess resistance transfer and plasmid mobilization (e.g., pBR325).

Main Results:

• Several Enterobacteriaceae strains exhibited high-molecular-weight plasmids and antibiotic resistance.
• These strains efficiently transferred resistance to recipient cells (10^2–10^7 transconjugants/ml).
• Resistant isolates mobilized the laboratory plasmid pBR325 into plasmid-free recipients.

Conclusions:

• Environmental Enterobacteriaceae possess plasmids conferring antibiotic resistance.
• These bacteria can act as vectors for antibiotic resistance gene dissemination in the environment.
• The potential for horizontal gene transfer and plasmid mobilization poses a significant environmental and public health risk.