Background: The Lactococcus strain of bacteria has been introduced as a probiotic nasal rinse for alleged salubrious effects on the sinonasal bacterial microbiome. However, data regarding interactions with pathogenic bacteria within the sinuses are lacking. The purpose of this study is to assess the interaction between L. lactis and patient-derived Pseudomonas aeruginosa, an opportunistic pathogen in recalcitrant chronic rhinosinusitis (CRS). Methods: Commercially available probiotic suspension containing L. lactis W136 was grown in an anaerobic chamber and colonies were isolated. Colonies were co-cultured with patient-derived P. aeruginosa strains in the presence of porcine gastric mucin (mimicking human mucus) for 72 hours. P. aeruginosa cultures without L. lactis served as controls. Colony forming units (CFUs) were compared. Results: Six P. aeruginosa isolates collected from 5 CRS patients (3 isolates from cystic fibrosis [CF], 1 mucoid strain) and laboratory strain PAO1 were co-cultured with L. lactis. There was no statistical difference in CFUs of 5 P. aeruginosa isolates grown with L. lactis compared to CFUs without presence of L. lactis. CFU counts were much higher when the mucoid strain was co-cultured with L. lactis (CFU+L.lactis = 1.9 × 108 ± 1.44 × 107, CFU–L.lactis = 1.3 × 108 ± 8.9 × 106, p = 0.01, n = 7). L. lactis suppressed the growth of 1 P. aeruginosa strain (CFU+L.lactis = 2.15 × 108 ± 2.9 × 107, CFU–L.lactis = 3.95 × 108 ± 4.8 × 106, p = 0.03, n = 7). Conclusion: L. lactis suppressed the growth of 1 patient P. aeruginosa isolate and induced growth of another (a mucoid strain) in in vitro co-culture setting in the presence of mucin. Further experiments are required to assess the underlying interactions between L. lactis and P. aeruginosa.
Bibliographical noteFunding Information:
sources for the study: NIH (National Heart, Lung, and Blood Institute [NHLBI] 1 R01 HL133006-04 to B.A.W.; National Institute of Diabetes and Digestive and Kidney Diseases [NIDDK] 5P30DK072482-04, CF Research Center Pilot Award to B.A.W.; National Institutes of Allergy and Infectious Disease [NIAID] K08AI146220); John W. Kirklin Research and Education Foundation Fellowship Award; UAB Faculty Development Research Award; American Rhinologic Society New Investigator Award; and Cystic Fibrosis Foundation Research Development Pilot grant (ROWE15R0) to D.Y.C.
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- Lactococcus lactis
- chronic rhinosinusitis
- nasal rinse
- sinus rinse