It has become evident that aggregation or biofilm formation is an important survival mechanism for bacteria in almost any environment. In this review

Acute respiratory tract infections (ARIs) are among the most prevalent infections in childhood worldwide, with the highest incidence among children younger than 2 years.^1,2 Risk factors for these infections include being male, living in crowded conditions, and being exposed to child care centers and passive smoking.^1,3 However, these factors explain only a fraction of the variation in incidence between children. Mannose-binding lectin (MBL) is a serum protein believed to play an important role in the innate immune response.⁴ A single gene, MBL2, located at chromosome 10, codes for human MBL.^5,6 Mannose-binding lectin may exert its action through binding to high mannose and N-acetylglucosamine oligosaccharides present on a variety of microorganisms, thereby activating the complement system by MBL-associated serine proteases and interacting with novel receptors on phagocytes.^7-9 As part of the innate immune system, the protein is considered particularly important in the vulnerable period of infancy before adequate specific immune protection is established by the adaptive immune system.¹⁰

Bacterial biofilms are known to be extremely tolerant toward antibiotics and other antimicrobial agents. These biofilms cause the persistence of chronic infections. Since antibiotics rarely resolve these infections, the only effective treatment of chronic infections is surgical removal of the infected implant, tissue, or organ and thereby the biofilm. Acetic acid is known for its antimicrobial effect on bacteria in general, but has never been thoroughly tested for its efficacy against bacterial biofilms. In this article, we describe complete eradication of both Gram-positive and Gram-negative biofilms using acetic acid both as a liquid and as a dry salt. In addition, we present our clinical experience of acetic acid treatment of chronic wounds. In conclusion, we here present the first comprehensive in vitro and in vivo testing of acetic acid against bacterial biofilms.