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Microorganisms and leukocytes in purulent sinusitis: a symbiotic relationship in metabolism
K M Westrin1, P Stierna, K Söderlund
1Department of Oto-Rhino-Laryngology, Huddinge University Hospital, Sweden.
Abstract:
Since the exchange of gases, as well as metabolites, is greatly impeded in a paranasal sinus empyema, it is not unlikely that certain organic substances be retained and accumulated in purulent secretion. In this study, secretions aspirated from experimentally infected maxillary sinuses of 26 rabbits were analysed biochemically. Quantitatively, by far the most important acid accumulated in secretions was lactic acid. Lactate induces metabolic acidosis and exerts an inhibitory effect on mammalian defense mechanisms. Lactate may also be used as an energy source by certain microorganisms. In spite of its leukocytic origin lactic acid thus promotes the continuation of a bacterial infection. In addition, certain other organic acids of bacterial origin were found, which, in different ways, contribute to the impediment of antimicrobial defense functions.
Insights
In paranasal sinus empyema, lactic acid accumulates in secretions, hindering immune defenses and promoting bacterial infection. Other organic acids also impair antimicrobial functions, prolonging illness.
Area of Science:
- Biochemistry
- Microbiology
- Immunology
Background:
- Paranasal sinus empyema impedes gas and metabolite exchange.
- Accumulation of organic substances in purulent secretions is likely.
Purpose of the Study:
- To biochemically analyze organic acid accumulation in experimentally induced maxillary sinus empyema in rabbits.
- To understand the role of these acids in infection and immune response.
Main Methods:
- Aspiration of purulent secretions from experimentally infected rabbit maxillary sinuses (n=26).
- Biochemical analysis of the aspirated secretions.
Main Results:
- Lactic acid was the predominant accumulated acid.
- Lactate was identified as a potential energy source for microorganisms.
- Other bacterial organic acids were detected, impairing antimicrobial defenses.
Conclusions:
- Accumulated lactic acid contributes to metabolic acidosis and inhibits mammalian defense mechanisms.
- Lactic acid promotes bacterial infection continuation despite its leukocytic origin.
- Bacterial organic acids collectively impede antimicrobial defense functions in empyema.