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Nutritionally deficient streptococci: electron microscopic study of 14 strains isolated in bacterial endocarditis
Abstract:
Fourteen strains of nutritionally deficient streptococci were isolated from patients with bacterial endocarditis and observed by light and electron microscopy. In brain-heart infusion broth supplemented wit Isovitalex, they could be distributed into three morphological groups in which numerous abnormalities involving septation or cell wall structure were showed. Group I (strains 7, 8, 13, 14) was characterized by coccobacilli resulting from failure of cross wall formation between two cocci. Cell wall structure was normal. Group II (strains 2, 4, 5, 11, 12) was characterized by long chains of elongated bacteria (rod-shaped bacteria) resulting from failure of cross wall formation and failure of separation of daughter cells after division; cell wall structure was normal. Group III (strains 1, 3, 6, 9, 10) was characterized by different abnormalities of cell wall thickness and structure. The cell wall was irregularly enlarged (strains 9, 10), thick and stratified (strain 1), or desquamating (strains 3, 6). These abnormalities of septation with or without abnormalities of cell wall appear to be much more important than those observed on normal streptococci during unbalanced growth in deprived media. They can be compared to the abnormalities shown in vivo by the bacteria of the dental plaque. The differences observed between the strains might be due to different metabolic deficiencies.
Insights
Nutritionally deficient streptococci from endocarditis patients showed varied cell abnormalities. These bacterial defects in septation and cell wall structure may relate to metabolic deficiencies.
Area of Science:
- Microbiology
- Cell Biology
- Bacterial Pathogenesis
Background:
- Nutritionally deficient streptococci are implicated in bacterial endocarditis.
- Understanding their morphology is crucial for comprehending disease mechanisms.
Purpose of the Study:
- To characterize the morphological abnormalities of nutritionally deficient streptococci isolated from endocarditis patients.
- To investigate the relationship between cell wall/septation defects and potential metabolic deficiencies.
Main Methods:
- Isolation of fourteen strains of nutritionally deficient streptococci from endocarditis patients.
- Observation using light and electron microscopy.
- Cultivation in supplemented brain-heart infusion broth.
Main Results:
- Three distinct morphological groups were identified based on septation and cell wall abnormalities.
- Group I: Coccobacilli due to failed cross wall formation.
- Group II: Elongated bacteria in chains due to failed septation and cell separation.
- Group III: Diverse cell wall abnormalities including irregular enlargement, thickening, stratification, and desquamation.
Conclusions:
- Observed septation and cell wall abnormalities are significant, exceeding those in nutrient-deprived normal streptococci.
- These in vitro findings may correlate with in vivo bacterial morphology, such as in dental plaque.
- Strain-specific differences suggest underlying metabolic deficiencies contribute to observed morphological variations.