A tolC-like protein of actinobacillus pleuropneumoniae is involved in antibiotic resistance and biofilm formation

Ying Li, Sanjie Cao, Luhua Zhang, Gee W. Lau, Yiping Wen, Rui Wu, Qin Zhao, Xiaobo Huang, Qigui Yan, Yong Huang, Xintian Wen

Research output: Contribution to journalArticle


Actinobacillus pleuropneumoniae is the etiologic agent of porcine contagious pleuropneumonia, a significant disease that causes serious economic losses to the swine industry worldwide. Persistent infections caused by bacterial biofilms are recalcitrant to treat because of the particular drug resistance of biofilm-dwelling cells. TolC, a key component of multidrug efflux pumps, are responsible for multidrug resistance (MDR) in many Gram-negative bacteria. In this study, we identified two TolC-like proteins, TolC1 and TolC2, in A. pleuropneumoniae. Deletion of tolC1, but not tolC2, caused a significant reduction in biofilm formation, as well as increased drug sensitivity of both planktonic and biofilm cells. The genetic-complementation of the tolC1 mutation restored the competent biofilm and drug resistance. Besides, biofilm formation was inhibited and drug sensitivity was increased by the addition of phenylalanine-arginine beta-naphthylamide (PAβN), a well-known efflux pump inhibitor (EPI), suggesting a role for EPI in antibacterial strategies toward drug tolerance of A. pleuropneumoniae. Taken together, TolC1 is required for biofilm formation and is a part of the MDR machinery of both planktonic and biofilm cells, which could supplement therapeutic strategies for resistant bacteria and biofilm-related infections of A. pleuropneumoniae clinical isolate SC1516.

Original languageEnglish (US)
Article number1618
JournalFrontiers in Microbiology
Issue numberOCT
StatePublished - Oct 24 2016


  • Biofilm formation
  • Multidrug resistance
  • PAβN Actinobacillus pleuropneumoniae
  • TolC

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)

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