Regulatory effects of macrolides on bacterial virulence: potential role as quorum-sensing inhibitors.
Pseudomonas aeruginosa is an opportunistic pathogen, and this organism is a major cause of pulmonary damage and mortality in patients with cystic fibrosis (CF), diffuse panbronchiolitis (DPB) and other forms of bronchiectasis. A break-through in the treatment of DPB and associated chronic P. aeruginosa pulmonary infection was realized when a patient with DPB improved dramatically after treatment with erythromycin for years. Now, long-term macrolide therapy has become a first line of treatment in DPB patients, and the immunomodulatory properties have now been extended to other clinical settings, including CF. An important factor in the pathogenesis of chronic P. aeruginosa infection is a bacterial cell-to-cell signaling mechanism, referred to as "quorum sensing", which enables bacteria to coordinately turn on and off specific virulence genes through the production of autoinducer molecules. Interference or blocking of quorum-sensing systems has been considered an attractive therapeutic strategy. Clinical and basic science data suggests the potential of macrolides as relevant inhibitors of the Pseudomonas quorum-sensing system. In fact, certain macrolides strongly suppressed quorum-sensing associated genes and autoinducer production, in addition to inhibition of a variety of virulence factors. In this review, clinical efficacy of macrolides on DPB and CF patients will be briefly summarized. Additionally, the mechanisms of action of macrolides will be discussed from the standpoint of sub-MIC macrolide effects on P. aeruginosa, particularly the ability of this antibiotic to suppress quorum-sensing systems, which may be crucial in the pathogenesis of chronic P. aeruginosa infection.
Tateda
Kazuhiro
K
Department of Microbiology and Infectious Disease, Toho University School of Medicine, 5-21-16 Ohmorinishi, Ohtaku, Tokyo 143-8540, Japan. kazu@med.toho-u.ac.jp
Standiford
Theodore J
TJ
Pechere
Jean Claude
JC
Yamaguchi
Keizo
K
D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001988:Bronchiolitis / Q000150:complications / Q000188:drug therapy; D003550:Cystic Fibrosis / Q000150:complications / Q000188:drug therapy; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D006801:Humans; D018942:Macrolides / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D008826:Microbial Sensitivity Tests / Q000379:methods; D011552:Pseudomonas Infections / Q000150:complications / Q000188:drug therapy / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000235:genetics / Q000472:pathogenicity; D014774:Virulence / Q000187:drug effects / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D018942:Macrolides