title: SCCmec-associated psm-mec mRNA promotes Staphylococcus epidermidis biofilm formation.
abstract: Biofilm formation is considered the major pathogenic mechanism of Staphylococcus epidermidis-associated nosocomial infections. Reports have shown that SCCmec-associated psm-mec regulated methicillin-resistant Staphylococcus aureus virulence and biofilm formation. However, the role of psm-mec in S. epidermidis remains unclear. To this purpose, we analysed 165 clinical isolates of S. epidermidis to study the distribution, mutation and expression of psm-mec and the relationship between this gene and biofilm formation. Next, we constructed three psm-mec deletion mutants, one psm-mec transgene expression strain (p221) and two psm-mec point mutant strains (pM, pAG) to explore its effects on S. epidermidis biofilm formation. Then, the amount of biofilm formation, extracellular DNA (eDNA) and Triton X-100-induced autolysis of the constructed strains was measured. Results of psm-mec deletion and transgene expression showed that the gene regulated S. epidermidis biofilm formation. Compared with the control strains, the ability to form biofilm, Triton X-100-induced autolysis and the amount of eDNA increased in the p221 strain and the two psm-mec mutants pM and pAG expressed psm-mec mRNA without its protein, whereas no differences were observed among the three constructed strains, illustrating that psm-mec mRNA promoted S. epidermidis biofilm formation through up-regulation of bacterial autolysis and the release of eDNA. Our results reveal that acquisition of psm-mec promotes S. epidermidis biofilm formation.
authors: Key Laboratory of Diagnostic Medicine (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China.
authors: Yongchang
authors: Y
authors: Yang
authors: Key Laboratory of Diagnostic Medicine (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China.
authors: Xuemei
authors: X
authors: Zhang
authors: Department of Clinical Laboratory, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, 610072, China.
authors: Wenfang
authors: W
authors: Huang
authors: Key Laboratory of Diagnostic Medicine (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China. yibingyin115@163.com.
authors: Yibing
authors: Y
authors: Yin
mesh_terms: D018441:Biofilms; D004269:DNA, Bacterial; D018076:DNA, Complementary; D055786:Gene Knockout Techniques; D005798:Genes, Bacterial; D006801:Humans; D016106:Methicillin Resistance; D012333:RNA, Messenger; D060888:Real-Time Polymerase Chain Reaction; D013212:Staphylococcus epidermidis / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial; D018076:DNA, Complementary; D012333:RNA, Messenger
keywords: Biofilm formation; Methicillin-resistant Staphylococcus epidermidis; SCCmec-associated psm-mec