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

Background: 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.

Objectives: To test if Pa-IgY decreases the concentration of P. aeruginosa in bronchoalveolar lavage in experimental porcine pneumonia over 27 hours.

Method: 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.

Results: BAL bacterial concentration increased in both groups and peaked at 10  ± 10  CFU/mL in the intervention group vs 10 .  ± 10  CFU/mL in the control group (n.s.). BAL bacterial concentration decreased during the experiment to 10  ± 10 .  CFU/mL in the intervention group vs 10  ± 10 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).

Conclusion: 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.