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Updated: Nov 8, 2025
Cystic Fibrosis Aggregate Biofilm Model to Study Infection-relevant Gene Expression
Published on: April 18, 2025
Impact of pmrA on Cronobacter sakazakii planktonic and biofilm cells: A comprehensive transcriptomic study
Zhenbo Xu1, Ziqi Liu2, Thanapop Soteyome3
1School of Food Science and Engineering, Guangdong Province Key Laboratory for Green Processing of Natural Products and Product Safety, South China University of Technology, Guangzhou, 510640, China; Department of Clinical Pharmacy and Translational Science, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, 38103, USA; Home Economics Technology, Rajamangala University of Technology Phra Nakhon, Bangkok, Thailand; National Institute of Fundamental Studies, Hantana Road, Kandy, Sri Lanka; Overseas Expertise Introduction Center for Discipline Innovation of Food Nutrition and Human Health (111 Center), Guangzhou, 510640, China.
Abstract:
Cronobacter sakazakii is an emerging opportunistic foodborne pathogen causing rare but severe infections in neonates. Furthermore, the formation of biofilm allows C. sakazakii to persist in different environments. We have demonstrated that the mutator phenotype ascribed to deficiency of the pmrA gene results in more biomass in the first 24 h but less during the post maturation stage (7-14 d) compared with BAA 894. The present study aimed to investigate the regulatory mechanism modulating biofilm formation due to pmrA mutation. The transcriptomic analyses of BAA 894 and s-3 were performed by RNA-sequencing on planktonic and biofilm cells collected at different time points. According to the results, when comparing biofilm to planktonic cells, expression of genes encoding outer membrane proteins, lysozyme, etc. were up-regulated, with LysR family transcriptional regulators, periplasmic proteins, etc. down-regulated. During biofilm formation, cellulose synthase operon genes, flagella-related genes, etc. played essential roles in different stages. Remarkably, pmrA varies the expression of a number of genes related to motility, biofilm formation, and antimicrobial resistance, including srfB, virK, mviM encoding virulence factor, flgF, fliN, etc. encoding flagellar assembly, and marA, ramA, etc. encoding AraC family transcriptional regulators in C. sakazakii. This study provides valuable insights into transcriptional regulation of C. sakazakii pmrA mutant during biofilm formation.
Insights
Cronobacter sakazakii biofilm formation is altered by pmrA gene mutations. The pmrA mutant shows changes in gene expression related to motility, virulence, and antimicrobial resistance, impacting biofilm development.
Area of Science:
- Microbiology
- Food Safety
- Genetics
Background:
- Cronobacter sakazakii is an opportunistic foodborne pathogen linked to severe neonatal infections.
- Biofilm formation enables C. sakazakii persistence in various environments.
- A pmrA gene mutation affects C. sakazakii biomass production over time.
Purpose of the Study:
- To investigate the regulatory mechanisms controlling biofilm formation in a C. sakazakii pmrA mutant.
- To understand the transcriptomic differences between wild-type and pmrA mutant strains during biofilm development.
Main Methods:
- Transcriptomic analysis using RNA-sequencing.
- Comparison of gene expression in planktonic and biofilm cells at different time points.
- Analysis of wild-type (BAA 894) and pmrA mutant (s-3) strains.
Main Results:
- pmrA mutation alters gene expression related to motility, biofilm formation, and antimicrobial resistance.
- Genes involved in outer membrane proteins and lysozyme were upregulated in biofilm cells.
- Cellulose synthase and flagella-related genes are crucial for different biofilm stages.
Conclusions:
- The pmrA gene plays a significant role in regulating C. sakazakii biofilm formation.
- Understanding these transcriptional changes offers insights into pathogen persistence and control strategies.
- The study highlights the complex genetic regulation underlying C. sakazakii biofilm development.
