Oxygen Tensions and Infections: Modulation of Microbial Growth, Activity of Antimicrobial Agents, and Immunologic Responses

Abstract

Oxygen tensions play an important role in the outcome of infections. Oxygen is cidal or static for microorganisms that lack defenses against oxidants. Hyperoxia and hyperbaric oxygen exert antimicrobial effects by increasing the intracellular flux of reactive oxygen species. In bacteria, such species cause DNA strand breaks, degradation of RNA, inhibition of amino acid biosynthesis, and inactivation of membrane transport proteins. Oxygen tensions also affect the activity of antimicrobial agents. In general, hyperoxia potentiates while anaerobiosis decreases the activity of many antimicrobial drugs. With regard to host defenses, hyperoxia elevates oxygen tensions in infected tissues to levels that facilitate oxygen-dependent killing by leukocytes. Prolonged hyperoxia inhibits DNA synthesis in lymphocytes and impairs chemotactic activity, adherence, phagocytic capacity, and generation of the oxidative burst in polymorphonuclear leukocytes and macrophages.

Topical Wound Oxygen Versus Conventional Compression Dressings in the Management of Refractory Venous Ulcers

“…Hyperbaric oxygen promotes angiogenesis and increases the expression of angiogenesisrelated growth factors [33,34]. It promotes leukocyte function with enhanced bactericidal activity [35][36][37][38][39][40]. The intermittent cycled pressure, under which TWO 2 is delivered, stimulates circulation, reduces oedema and provides a sealed humidified environment essential for healing [41].…”

The Pathology ofMycobacterium tuberculosisInfection

“…Interestingly, the upper lung lobes of the human favor bacillary growth due to higher oxygen pressure and delayed immune responses. 160 Despite wide dissemination of Mtb during primary infection, the majority of infected, but otherwise healthy, individuals resolve these lesions without becoming symptomatic. Approximately 10% of infected individuals, however, develop severe, life-threatening disease or primary progressive disease at this stage.…”

Hyperbaric Oxygen Therapy in the Treatment of Necrosis and Gangrene

“…Prolonged hyperoxia inhibits DNA synthesis in lymphocytes and impairs chemotactic activity, adherence, phagocytic capacity, and generation of the oxidative burst in polymorphonuclear leukocytes and macrophages. (Park et al, 1992;Cimsit, 2009). One of the suggested criteria for hyperbaric oxygen therapy use is transcutaneous oxygen measurement of less than 40 mm Hg at the tissues surrounding the wound, most precisely, at the wound edges.…”