Bacteriophage Mu contamination impacts interbacterial competition

Area of Science:

• Microbiology
• Bacteriology
• Virology

Background:

• The Citrobacter rodentium DBS100 ∆cpxRA mutant strain is widely used in research.
• Bacteriophage contamination can significantly alter bacterial physiology and experimental outcomes.
• Previous studies may have been impacted by undetected phage contamination.

Purpose of the Study:

• To identify and characterize bacteriophage Mu contamination in the Citrobacter rodentium DBS100 ∆cpxRA mutant.
• To re-evaluate experimental results previously obtained with the contaminated strain.
• To emphasize the importance of using phage-free strains in microbiological research.

Main Methods:

• Identification of bacteriophage Mu in the Citrobacter rodentium DBS100 ∆cpxRA strain.
• Re-construction of a Mu-free ∆cpxRA strain.
• Replication of experimental assays, including interbacterial competition, using both contaminated and Mu-free strains.

Main Results:

• Bacteriophage Mu contamination was confirmed in the commonly used DBS100 ∆cpxRA strain.
• The presence of Mu significantly impacted the outcome of interbacterial competition assays.
• Mu-contaminated strains consistently outcompeted Mu-free competitors in these assays.

Conclusions:

• The widespread use of the contaminated strain necessitates re-evaluation of previous findings.
• Phage contamination, particularly from conjugal donor strains, can confound experimental results.
• Strict quality control measures, including the use of Mu-free donor strains, are crucial for reliable microbiological research.