Abstract
Mycoplasma gallisepticum (MG) causes chronic respiratory disease in chickens, leading to severe economic losses to the poultry industry. Currently the disease is managed with antimicrobials and vaccination; however, emergence of multi-drug resistant Mycoplasma and the limited effect of vaccines necessitate development of novel approaches. A library of 4,182 small molecules (SMs) was screened for identification of narrow spectrum anti-MG compounds using high throughput screening. A total of 584 SMs were identified. Ten SMs possessed low MICs (0.78–100 μM) with efficacy against multiple MG strains and MG biofilm. These 10 SMs did not affect commensal/probiotic bacteria and other avian and foodborne pathogens. They displayed no or little toxicity on the avian macrophage HD-11 cells, human epithelial Caco-2 cells, and chicken red blood cells (RBCs); but, they were effective in reducing MG in chicken RBCs. Six SMs (SM1, SM3−5, and SM9−10) were tested in three-week-old chickens infected with MG (nasal spray; 109 CFU/bird). SM4 and SM9 reduced airsacculitis by 77.2 % and 82.9 %, MG load in the trachea by 0.9 log (p < 0.05) and 2.7 log (p < 0.0001), and tracheal mucosal thickness by 23 % and 61 %, respectively with no impact on the richness and evenness of the cecal (P = 0.6; H = 1.0) and tracheal (P = 0.8; H = 0.8) microbiota compared to the MG-infected controls. Both SM4 and SM9 treatments resulted in a significant alteration in the cell membrane conformation of MG. In conclusion; we identified two novel growth inhibitors of MG that are effective in chickens. These findings will facilitate development of novel antibacterials to control mycoplasmosis in poultry.
Original language | English |
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Article number | 108799 |
Journal | Veterinary Microbiology |
Volume | 247 |
DOIs | |
State | Published - Aug 2020 |
Bibliographical note
Funding Information:Research in Dr. Rajashekara’s laboratory is funded by Agriculture and Food Research Initiative Competitive Grant # 2015-68004-23131 from the National Institute for Food and Agriculture (NIFA) , U.S. Department of Agriculture (USDA) .
Publisher Copyright:
© 2020 Elsevier B.V.
Keywords
- Cell membrane
- Chickens
- Growth inhibitors
- Microbiota
- Mycoplasma gallisepticum
- Small molecules
ASJC Scopus subject areas
- Microbiology
- General Veterinary