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Super-resolution Imaging of Proteus mirabilis Biofilm by Expansion Microscopy
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Differences in biofilm formation and aggregative adherence between beta-lactam susceptible and beta-lactamases

Elisabetta Nucleo1, Giulia Fugazza, Roberta Migliavacca

  • 1Department of Morphological, Eidological and Clinical Sciences, Section of Microbiology, University of Pavia, Pavia, Italy. elicleo@libero.it

The New Microbiologica
|April 21, 2010
PubMed

Insights

Multidrug resistant Proteus mirabilis strains from a rehabilitation facility formed biofilms. Beta-lactamase producing strains showed enhanced biofilm formation, contributing to urinary tract persistence.

Area of Science:

  • Microbiology
  • Infectious Diseases
  • Antimicrobial Resistance

Background:

  • Multidrug resistant (MDR) extended-spectrum beta-lactamase (ESbetaL) producing Proteus mirabilis poses a significant threat in healthcare settings.
  • Biofilm formation is a key virulence factor contributing to persistent infections and treatment challenges.

Purpose of the Study:

  • To evaluate biofilm formation in MDR ESbetaL-producing Proteus mirabilis isolates from a long-term care and rehabilitation facility (LTCRF).
  • To investigate the relationship between beta-lactamase production and biofilm formation capacity.

Main Methods:

  • Standard adherence assays on titer plates using Luria Bertani (LB) medium, diluted LB, and urine.
  • Biofilm production assessment in microtiter plates with sub-inhibitory concentrations of beta-lactams.
  • Screening for aggregative adherence onto monkey kidney cells (LLC-MK2).

Main Results:

  • All 10 Proteus mirabilis strains demonstrated biofilm formation capabilities to varying degrees.
  • Beta-lactamase positive strains exhibited statistically significant enhanced biofilm formation compared to negative strains across different media.
  • Isolates showed a greater adherence to inert surfaces than to cellular surfaces.

Conclusions:

  • While a direct correlation was not fully established, beta-lactamase production appears to enhance biofilm formation in Proteus mirabilis.
  • Both biofilm formation and beta-lactamase production are crucial mechanisms for bacterial persistence in the urinary tract.
  • Findings highlight the importance of understanding these mechanisms for infection control in LTCRFs.

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