Bronchially instilled IgY-antibodies did not decrease pulmonary p. aeruginosa concentration in experimental porcine pneumonia.

Abstract

P. aeruginosa possesses antibiotic resistance, making treatment difficult. Polyclonal anti-P. aeruginosa IgY-antibodies (Pa-IgY) have antibacterial effects, but have not been studied in large animal pneumonia. To test if Pa-IgY decreases the concentration of P. aeruginosa in bronchoalveolar lavage in experimental porcine pneumonia over 27 hours. Norwegian landrace pigs were anesthetized, mechanically ventilated, and subject to invasive monitoring. The animals were randomized to receive either P. aeruginosa (control, n = 12) or P aeruginosa + Pa-IgY antibodies with a repeated dose of Pa-IgY after 12 hours (intervention, n = 12) in the right lower pulmonary lobe. Bronchoalveolar lavage (BAL) cultures and physiological measurements were obtained repeatedly for 27 hours after which the pigs were sacrificed. BAL bacterial concentration increased in both groups and peaked at 10^7.28  ± 10^0.21  CFU/mL in the intervention group vs 10⁷ .³⁶  ± 10^0.50  CFU/mL in the control group (n.s.). BAL bacterial concentration decreased during the experiment to 10^5.35  ± 10⁰ .³⁹  CFU/mL in the intervention group vs 10^5.19  ± 10^0.37 in the control group (n.s.). The intervention group had lower heart rate (P < .001), lower cardiac index (P < .01), and lower arterial lactate (P < .001) compared to the control group. The core temperature was lower in the intervention group than in the control group (P < .001). The chosen dose of Pa-IgY did not decrease concentrations of P. aeruginosa in BAL over 27 hours. We conclude that it is unlikely that there is a large effect of this specific dose and route of administration of Pa-IgY in this type of model.