Proximity-dependent inhibition of growth of Mannheimia haemolytica by Pasteurella multocida.
Appl Environ Microbiol
; 78(18): 6683-8, 2012 Sep.
Article
in En
| MEDLINE
| ID: mdl-22798357
ABSTRACT
Mannheimia haemolytica, Pasteurella multocida, and Bibersteinia trehalosi have been identified in the lungs of pneumonic bighorn sheep (BHS; Ovis canadensis). Of these pathogens, M. haemolytica has been shown to consistently cause fatal pneumonia in BHS under experimental conditions. However, M. haemolytica has been isolated by culture less frequently than the other bacteria. We hypothesized that the growth of M. haemolytica is inhibited by other bacteria in the lungs of BHS. The objective of this study was to determine whether P. multocida inhibits the growth of M. haemolytica. Although in monoculture both bacteria exhibited similar growth characteristics, in coculture with P. multocida there was a clear inhibition of growth of M. haemolytica. The inhibition was detected at mid-log phase and continued through the stationary phase. When cultured in the same medium, the growth of M. haemolytica was inhibited when both bacteria were separated by a membrane that allowed contact (pore size, 8.0 µm) but not when they were separated by a membrane that limited contact (pore size, 0.4 µm). Lytic bacteriophages or bactericidal compounds could not be detected in the culture supernatant fluid from monocultures of P. multocida or from P. multocida-M. haemolytica cocultures. These results indicate that P. multocida inhibits the growth of M. haemolytica by a contact- or proximity-dependent mechanism. If the inhibition of growth of M. haemolytica by P. multocida occurs in vivo as well, it could explain the inconsistent isolation of M. haemolytica from the lungs of pneumonic BHS.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Sheep Diseases
/
Pasteurella multocida
/
Mannheimia haemolytica
/
Pneumonia, Bacterial
/
Antibiosis
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Appl Environ Microbiol
Year:
2012
Document type:
Article
Affiliation country:
United States
Publication country:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA