Related Experiment Video
Updated: Jul 10, 2026
09:39
A Platform of Anti-biofilm Assays Suited to the Exploration of Natural Compound Libraries
Published on: December 27, 2016
Subinhibitory concentrations of azithromycin decrease nontypeable Haemophilus influenzae biofilm formation and
Timothy D Starner1, Joshua D Shrout, Matthew R Parsek
1Department of Pediatrics, University of Iowa, 2080H Medical Laboratories, 200 Hawkins Drive, Iowa City, IA 52242, USA. timothy-starner@uiowa.edu
Antimicrobial Agents and Chemotherapy
|October 24, 2007
Summary
Subinhibitory azithromycin concentrations effectively reduce Nontypeable Haemophilus influenzae (NTHi) biofilm formation and thickness. This antibiofilm activity supports azithromycin
Area of Science:
- Microbiology
- Infectious Diseases
- Pharmacology
Background:
- Nontypeable Haemophilus influenzae (NTHi) is a significant pathogen causing respiratory infections.
- Chronic NTHi infections are often associated with biofilms, complicating treatment.
- The mechanism of long-term azithromycin's clinical benefit in chronic lung diseases is not fully understood.
Purpose of the Study:
- To investigate the effect of subinhibitory azithromycin concentrations on NTHi biofilm formation.
- To determine if azithromycin exhibits antibiofilm properties against NTHi.
- To compare the antibiofilm activity of azithromycin with gentamicin.
Main Methods:
- NTHi strains (laboratory and clinical isolates) were cultured in flow-cell and static biofilm models.
- Biofilm formation and persistence were quantified using varying concentrations of azithromycin and gentamicin.
- Antibiotic susceptibility, including minimum inhibitory concentration (MIC), was assessed.
Main Results:
- Subinhibitory azithromycin significantly reduced NTHi biofilm biomass and thickness.
- Gentamicin showed no effect on biofilm formation at subinhibitory concentrations.
- Established NTHi biofilms developed resistance to gentamicin, while azithromycin remained effective against most isolates.
Conclusions:
- Subinhibitory azithromycin possesses significant antibiofilm properties against NTHi.
- Azithromycin's antibiofilm activity provides a potential mechanism for its clinical efficacy in chronic NTHi infections.
- These findings support the use of azithromycin in managing chronic biofilm-associated H. influenzae infections.
Related Concept Videos
01:29Biofilms
Biofilms are complex communities of microorganisms encased in a self-produced extracellular polysaccharide matrix attached to surfaces. These microbial consortia can include single or multiple species, providing enhanced survival benefits by forming organized, multilayered structures.The formation of biofilms occurs through four key stages: attachment, colonization, development, and dispersal.During attachment, free-swimming planktonic cells adhere to a surface, often facilitated by...
01:28Gene Regulation in Microbial Communities: Quorum Sensing
Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...
01:28Inhibitors of Bacterial DNA Synthesis
Bacterial pathogens depend on precise and efficient DNA replication to sustain infection. Two type II topoisomerases—DNA gyrase and topoisomerase IV—are critical to this process, as they resolve DNA supercoiling and unlink chromosomes during replication. Fluoroquinolones, synthetic derivatives of quinolones, exploit this mechanism by stabilizing the transient DNA–enzyme cleavage complex, preventing strand religation, and causing lethal double-strand breaks. These antibiotics are selectively...
01:25Inhibitors of Bacterial Protein Synthesis
Aminoglycosides constitute a highly potent class of bactericidal antibiotics that exert their antimicrobial effects by targeting the bacterial ribosome, specifically disrupting protein synthesis. These polycationic molecules consist of amino-modified sugars linked via glycosidic bonds to an aminocyclitol core such as 2-deoxystreptamine or streptamine. Their strong positive charges facilitate tight binding to the negatively charged phosphate backbone of ribosomal RNA (rRNA), primarily at the 16S...