Effect of pH and osmolality on in vitro phagocytosis and killing by neutrophils in urine

Abstract

Phagocytosis and intracellular killing of two strains ofEscherichia coli and a Staphylococcus saprophyticus by polymorphonuclear neutrophils (PMN) in pooled sterile urine at three osmolalities (800, 485, and 200 mosMlkg of H20) between pHs 5 and 8 was investigated. Urine at 800 mosM virtually abolished phagocytosis of both E. coli strains, regardless of pH, and reduced the phagocytosis of S. saprophyticus to 30%; no killing of any organisms took place at this osmolality. On the other hand, phagocytosis was as good in urine as in Hanks balanced salt solution at both 485 and 200 mosM between pHs 6 and 8. Phagocytosis of all three strains was virtually abolished at pH 5. Killing of the strains by PMN was optimal between pHs 6.5 and 7.5 in urine at 485 mosM (being at least 90% of the control values in Hanks balanced salt solution), whereas at 200 mosM killing was reduced to 50 to 70%o of these values. Reduced killing of all three strains occurred at pH 8, whereas at pH 6 only S. saprophyticus was killed. Thus, the bactericidal activity of PMN in urine was more sensitive than 8

Inhibiting the immunoproteasome exacerbates the pathogenesis of systemic Candida albicans infection in mice

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The effects of pH on wound healing, biofilms, and antimicrobial efficacy

“…Collectively, these findings suggest a role for these environmental factors in susceptibility of wounds to infection. It was shown by Gargan et al 63 that neutrophil phagocytosis in urine was dependent on both osmolality and pH. Results revealed that phagocytosis by neutrophils was as good in urine as in Hanks balanced salt solution at both 485 and 200 mOsm at pH values between 6 and 8, whereas as at pH 5, phagocytosis of three bacterial strains was virtually abolished.…”

“…Collectively, these findings suggest a role for these environmental factors in susceptibility of wounds to infection. It was shown by Gargan et al . that neutrophil phagocytosis in urine was dependent on both osmolality and pH.…”

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