IMPORTANCE: Understanding how pneumococcal proteins affect the pathology of the middle ear and inner ear is important for the development of new approaches to prevent otitis media and its complications. OBJECTIVES: To determine the viability and virulence of Streptococcus pneumoniae mutants deficient in pneumolysin (Ply-) and pneumococcal surface protein A (PspA-) in the chinchilla middle ear. DESIGN: Bullae of chinchillas were inoculated bilaterally with wild-type (Wt), Ply-, PspA-, and Ply-/PspA- strains. Bacterial colony-forming units (CFUs) in middle ear effusions were counted at 48 hours. The CFUs of the PspA- group were also counted at 6 to 36 hours after inoculation. Temporal bone histopathological results were compared. SETTING AND PARTICIPANTS: Twenty-seven chinchillas in an academic research laboratory. EXPOSURE: Chinchilla middle ears were inoculated with S pneumoniae to produce sufficient volumes of effusions and noticeable histopathological changes in the ears. MAIN OUTCOMES AND MEASURES: The CFU counts in the middle ear effusions and histopathological changes were compared to determine the effect of pneumococcal protein mutations on chinchilla ears. RESULTS: At 48 hours, CFUs in middle ears were increased for the Wt and Ply-/PspA- strains, but Ply- remained near inoculum level. No bacteria were detected in the PspA- group. The CFUs of PspA- decreased over time to a low level at 30 to 36 hours. In vitro, PspA- in Todd-Hewitt broth showed an increase in bacterial growth of 2 logs at 43 hours, indicating PspA- susceptibility to host defenses in vivo. The PspA- and Ply- groups had fewer pathologic findings than the Wt or Ply-/PspA- groups. Histopathological analysis showed significant differences in the number of bacteria in the scala tympani in the Wt group compared with the Ply-, PspA-, and Ply-/PspA- groups. The PspA- strain was the least virulent. CONCLUSIONS AND RELEVANCE: The PspA- mutant was much less viable and less virulent in the ear than the Wt, Ply-, and Ply-/PspA- strains. There was no significant attenuation in the viability and virulence of the Ply-/PspA- mutant compared with the Wt or single mutants. The viability and virulence of pneumococcal mutants seemed to be protein and organ specific.
IMPORTANCE: Understanding how pneumococcal proteins affect the pathology of the middle ear and inner ear is important for the development of new approaches to prevent otitis media and its complications. OBJECTIVES: To determine the viability and virulence of Streptococcus pneumoniae mutants deficient in pneumolysin (Ply-) and pneumococcal surface protein A (PspA-) in the chinchilla middle ear. DESIGN: Bullae of chinchillas were inoculated bilaterally with wild-type (Wt), Ply-, PspA-, and Ply-/PspA- strains. Bacterial colony-forming units (CFUs) in middle ear effusions were counted at 48 hours. The CFUs of the PspA- group were also counted at 6 to 36 hours after inoculation. Temporal bone histopathological results were compared. SETTING AND PARTICIPANTS: Twenty-seven chinchillas in an academic research laboratory. EXPOSURE: Chinchilla middle ears were inoculated with S pneumoniae to produce sufficient volumes of effusions and noticeable histopathological changes in the ears. MAIN OUTCOMES AND MEASURES: The CFU counts in the middle ear effusions and histopathological changes were compared to determine the effect of pneumococcal protein mutations on chinchilla ears. RESULTS: At 48 hours, CFUs in middle ears were increased for the Wt and Ply-/PspA- strains, but Ply- remained near inoculum level. No bacteria were detected in the PspA- group. The CFUs of PspA- decreased over time to a low level at 30 to 36 hours. In vitro, PspA- in Todd-Hewitt broth showed an increase in bacterial growth of 2 logs at 43 hours, indicating PspA- susceptibility to host defenses in vivo. The PspA- and Ply- groups had fewer pathologic findings than the Wt or Ply-/PspA- groups. Histopathological analysis showed significant differences in the number of bacteria in the scala tympani in the Wt group compared with the Ply-, PspA-, and Ply-/PspA- groups. The PspA- strain was the least virulent. CONCLUSIONS AND RELEVANCE: The PspA- mutant was much less viable and less virulent in the ear than the Wt, Ply-, and Ply-/PspA- strains. There was no significant attenuation in the viability and virulence of the Ply-/PspA- mutant compared with the Wt or single mutants. The viability and virulence of pneumococcal mutants seemed to be protein and organ specific.
Authors: C F Rayner; A D Jackson; A Rutman; A Dewar; T J Mitchell; P W Andrew; P J Cole; R Wilson Journal: Infect Immun Date: 1995-02 Impact factor: 3.441
Authors: Stephen J Barenkamp; Tasnee Chonmaitree; Anders P Hakansson; Terho Heikkinen; Samantha King; Johanna Nokso-Koivisto; Laura A Novotny; Janak A Patel; Melinda Pettigrew; W Edward Swords Journal: Otolaryngol Head Neck Surg Date: 2017-04 Impact factor: 3.497
Authors: Patricia A Schachern; Vladimir Tsuprun; Patricia Ferrieri; David E Briles; Sarah Goetz; Sebahattin Cureoglu; Michael M Paparella; Steven Juhn Journal: Int J Pediatr Otorhinolaryngol Date: 2014-06-24 Impact factor: 1.675