Understanding the Interactions between <i>Staphylococcus aureus</i> and the Raw-Meat-Processing Environment Isolate <i>Klebsiella oxytoca</i> in Dual-Species Biofilms via Discovering an Altered Metabolic Profile

In a raw-meat-processing environment, members of the Enterobacteriaceae family can coexist with <i>Staphylococcus aureus</i> to form dual-species biofilms, leading to a higher risk of food contamination. However, very little is known about the effect of inter-species interactions on dual...

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Bibliographic Details
Main Authors: Xiaoxue Chen, Yunan Hu, Simin Tian, Beizhong Han
Format: Article
Language:English
Published: MDPI AG 2021-03-01
Series:Microorganisms
Subjects:
Online Access:https://www.mdpi.com/2076-2607/9/4/672
Description
Summary:In a raw-meat-processing environment, members of the Enterobacteriaceae family can coexist with <i>Staphylococcus aureus</i> to form dual-species biofilms, leading to a higher risk of food contamination. However, very little is known about the effect of inter-species interactions on dual-species biofilm formation. The aim of this study was to investigate the interactions between <i>S. aureus</i> and raw-meat-processing environment isolates of <i>Klebsiella oxytoca</i> in dual-species biofilms, by employing an untargeted metabolomics tool. Crystal violet staining assay showed that the biomass of the dual-species biofilm significantly increased and reached its maximum after incubation for 21 h, compared with that of single species grown alone. The number of <i>K. oxytoca</i> in the dual-species biofilm was significantly higher than that of <i>S. aureus</i>. Field emission scanning electron microscopy (FESEM) revealed that both species were evenly distributed, and were tightly wrapped by extracellular polymeric substances in the dual-species biofilms. Ultra-high-pressure liquid chromatography equipped with a quadrupole-time-of-flight mass spectrometer (UHPLC-Q-TOF MS) analysis exhibited a total of 8184 positive ions, and 6294 negative ions were obtained from all test samples. Multivariate data analysis further described altered metabolic profiling between mono- and dual-species biofilms. Further, 18 and 21 different metabolites in the dual-species biofilm were screened as biomarkers by comparing the mono-species biofilms of <i>S. aureus</i> and <i>K. oxytoca</i>, respectively. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways that were exclusively upregulated in the dual-species biofilm included ABC transporters, amino acid metabolism, and the two-component signal transduction system. Our results contribute to a better understanding of the interactive behavior of inter-species biofilm communities, by discovering altered metabolic profiling.
ISSN:2076-2607