Relationship between expressions of global regulators and erythromycin resistance of Staphylococcus epidermidis biofilm

    JIA Ning, XU Zhiª²Kai, YUAN Yunª²E, SUO Jiª²Jiang, XING Yuª²Bin

    1Department of Nosocomial Infection and Disease Control, PLA General Hospital, Beijing 100853, China

    2Department of Microbiology, School of Basic Medicine, Fourth Military Medical University, Xi¬ðan 710033, China

    ¡¾Abstract¡¿ AIM: To explore the relationship between the expressions of global regulators and the erythromycin resistance of Staphylococcus epidermidis (S. epidermidis) biofilm. METHODS: The expressions of global regulators (agr, sarA and sigB) in biofilm cells of S. epidermidis 1457 with and without erythromycin resistance were detected by SYBR green I realª²time RTª²PCR. RESULTS: The expressions of agrD and RNAIII were significantly higher in biofilm cells than those in planktonic cells in both erythromycin and nonª²erythromycin groups (P<0.05). The expression of sarA in biofilm cells was significantly higher than that in planktonic cells, but there was no significant difª²ference in biofilm cells between erythromycin group and nonª²erythromycin group. The expression of sigB and its active regulation gene asp23 in biofilm cells showed no significant difference between erythromycin and nonª²erythromycin groups (P>0.05). CONCLUSION: agrD and RNAIII take part in quorumª²sensing regulation, which suggests that quorumª²sensing system plays an important role in erythromycin resistance of S. epidermidis biofilm. ......