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Updated: Jul 8, 2026
Identification of Antibacterial Immunity Proteins in Escherichia coli using MALDI-TOF-TOF-MS/MS and Top-Down Proteomic Analysis
Published on: May 23, 2021
Proteomic analysis of ampicillin-resistant oral Fusobacterium nucleatum
M Al-Haroni1, N Skaug, V Bakken
1Department of Oral Sciences - Oral Microbiology, Faculty of Dentistry, and Centre of International Health, University of Bergen, Bergen, Norway. mohammed.al-haroni@student.uib
Introduction:
Fusobacterium nucleatum represents one of the predominant anaerobic species in the oral microbiota. Penicillin-resistant F. nucleatum have been isolated from intra- and extraoral infections. This study aimed to assess ampicillin resistance in F. nucleatum by investigating the synthesis of resistance-associated proteins.
Methods:
Ampicillin-resistant and ampicillin-susceptible F. nucleatum isolates were obtained from 22 dental plaque samples. Two-dimensional gel electrophoresis and mass spectrometry were used to investigate bacterial protein synthesis. Proteins exhibiting statistically significant quantitative changes between sensitive and resistant isolates were identified using peptide mass mapping and matrix-assisted laser desorption/ionization - time of flight/time of flight (MALDI-TOF/TOF) mass spectrometry.
Results:
Twenty-three F. nucleatum isolates were recovered from plaque samples and their ampicillin minimum inhibitory concentrations ranged between 0.125 microg/ml and 256 microg/ml. Analysis of the bacterial cellular proteins by two-dimensional gel electrophoresis resolved 154-246 distinct protein spots (mean 212, n = 9). Between 32% and 83% of the protein spots were common for the F. nucleatum isolates. Comparisons of the protein profiles of sensitive and resistant isolates revealed the presence of a 29 kDa protein and significant increases in the synthesis of two proteins at 37 and 46 kDa in the ampicillin-resistant F. nucleatum isolates. These proteins were identified as a class D beta-lactamase, ATP-binding cassette (ABC) transporter ATP-binding protein and enolase, respectively.
Conclusion:
Synthesis of a class D beta-lactamase by ampicillin-resistant F. nucleatum isolates could complicate antimicrobial treatment because these enzymes might confer resistance to many classes of beta-lactam antibiotics. The differences observed in protein synthesis between ampicillin-resistant and ampicillin-susceptible F. nucleatum may contribute to the antibiotic resistance and virulence of these bacteria.
Insights
Ampicillin-resistant Fusobacterium nucleatum synthesizes a class D beta-lactamase, complicating antibiotic treatment. This resistance is linked to altered protein synthesis, potentially increasing virulence in oral bacteria.
Area of Science:
- Microbiology
- Molecular Biology
- Antimicrobial Resistance
Background:
- Fusobacterium nucleatum is a common oral anaerobic bacterium.
- Penicillin-resistant strains are implicated in various infections.
- Understanding ampicillin resistance mechanisms is crucial.
Purpose of the Study:
- To investigate ampicillin resistance in F. nucleatum.
- To identify proteins associated with ampicillin resistance.
- To analyze differences in protein synthesis between resistant and susceptible strains.
Main Methods:
- Isolating ampicillin-resistant and susceptible F. nucleatum from dental plaque.
- Employing two-dimensional gel electrophoresis and mass spectrometry for protein analysis.
- Identifying differentially synthesized proteins using peptide mass mapping and MALDI-TOF/TOF.
Main Results:
- Identified ampicillin resistance in F. nucleatum isolates with MICs ranging from 0.125 to 256 microg/ml.
- Detected increased synthesis of a class D beta-lactamase (29 kDa), an ABC transporter ATP-binding protein (37 kDa), and enolase (46 kDa) in resistant strains.
- Observed significant quantitative changes in protein profiles between sensitive and resistant isolates.
Conclusions:
- The synthesis of class D beta-lactamase in resistant F. nucleatum may confer broad-spectrum beta-lactam antibiotic resistance.
- Altered protein synthesis contributes to ampicillin resistance and potential virulence.
- Findings highlight the need for monitoring resistance mechanisms in F. nucleatum.
