In an aqueous environment, ions are released from a bioactive glass (BAG) and the pH rises in its vicinity. This may influence both growth and colonization of microorganisms. We studied the effects of the BAG S53P4 on the atrophic rhinitis-associated microorganism Klebsiella ozaenae. The glass was used in the form of granules or discs. Growth inhibition was studied using an agar plate test. Adhesion was studied by incubating bacterial suspension with the glass. The effect of the presence of the bacteria on the formation of the Si-rich layer on the bioactive glass was also analyzed. Furthermore, a follow up study of 19 -74 months with ozena patients surgically treated with the BAG S53P4 was performed. The bioactive glass showed no clear growth inhibition of K. ozaenae in the agar plate test. K. ozaenae showed low adherence to the BAG S53P4. No growth of the microbe was seen on the glass during the 8 h incubations and the Si-rich layer was formed normally. The clinical follow-up study showed no infections of the implants and the symptoms of the patients were markedly reduced. Thus, the BAG S53P4 did not favor adhesion and colonization of K. ozaenae, in vitro, which is supported by the in vivo findings showing no BAG-associated infections or reinfections.