Identification and expression of nor efflux family genes in Staphylococcus epidermidis that act against gatifloxacin

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• 作者：Marco A. Juá ; rez-Verdayes^a ; ^{relf125@hotmail.com} ; Berenice Parra-Ortega^a ; ^d ; ^{paorbe1@yahoo.com.mx} ; Cé ; sar Herná ; ndez-Rodrí ; guez^a ; ^{chdez38@hotmail.com} ; Gabriel Betanzos-Cabrera^b ; ^{gbetanzo@uaeh.edu.mx} ; Sandra Rodrí ; guez-Martí ; nez^c ; ^{sandrarodm@yahoo.com.mx} ; Mario E. Cancino-Diaz^c ; ^{mcancinodiaz@yahoo.com.mx} ; Juan C. Cancino-Diaz^a ; ^{jccancinodiaz@hotmail.com}
• 关键词：NorA ; NorB ; Staphylococcus epidermidis ; Gatifloxacin ; Eye
• 刊名：Microbial Pathogenesis
• 出版年：2012
• 出版时间：June, 2012
• 年：2012
• 卷：52
• 期：6
• 页码：318-325
• 全文大小：585 K

文摘

NorA, NorB, and NorC are efflux proteins in the Nor family that regulate the secretion of fluoroquinolones, and MgrA/NorR is a transcription factor of the Nor family. Overexpression of Nor family proteins provides fluoroquinolone resistance in Staphylococcus aureus. However, in coagulase-negative staphylococci (CNS), members of the Nor family had not been identified. In this work, the presence of Nor family proteins in Staphylococcus spp. and the expression of Nor family in gatifloxacin resistant S. epidermidis strains obtained from ocular infections (OI) were identified and analyzed.

S.?epidermidis strains from OIs (n?=?44) and healthy skin (HS; n?=?52) were isolated. The nor family genes were identified in CNS using PCR, sequencing and phylogenetic approaches. Nor family expression was determined by RT-PCR. NorA efflux activity was determined using the automated ethidium bromide method.

In-silico analysis showed that norA, mgrA/norR, and ?em>norB-like?and ?em>norC-like?(norB/norC) genes are present in CNS. The nor family genes were distributed and constitutively expressed in all S.?epidermidis strains studied. In one gatifloxacin resistant strain isolated from the endophthalmitis, treatment with gatifloxacin induced overexpression of the norA gene and resulted in high activity of NorA efflux.

These results indicate that the Nor family of proteins is present in CNS, and the NorA efflux mechanism for gatifloxacin response occurs in at least one strain of S.?epidermidis, contributing to gatifloxacin resistance.