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Genetic heterogeneity among nutritionally deficient streptococci
1Division of AIDS, Medical Branch, NIAID, Rockville, Maryland.
Diagnostic Microbiology and Infectious Disease
|May 1, 1992
Summary
Nutritionally deficient streptococci (NDS) exhibit genetic diversity, challenging their classification. DNA analysis reveals significant heterogeneity within NDS, impacting understanding of their role in disease.
Area of Science:
- Microbiology
- Genetics
- Clinical Diagnostics
Background:
- Nutritionally deficient streptococci (NDS) are characterized by specific growth requirements.
- The genetic relatedness and precise speciation of NDS remain largely uncharacterized.
- Understanding NDS diversity is crucial for elucidating their pathogenesis and improving clinical management.
Purpose of the Study:
- To investigate the deoxyribonucleic acid (DNA) relatedness among nutritionally deficient streptococci (NDS).
- To improve the speciation of NDS through comprehensive biotyping and DNA-DNA hybridization.
- To assess the genetic heterogeneity within NDS populations.
Main Methods:
- Performed DNA-DNA hybridization on 23 NDS isolates.
- Conducted biotyping using the API Rapid Strept Identification method.
- Compared NDS strains with reference viridans streptococcal strains.
Main Results:
- Biochemical testing grouped NDS into three broad biotype categories, with one nontypeable strain.
- DNA-DNA hybridization revealed significant genetic heterogeneity among the NDS isolates.
- Only 17% of NDS isolates showed high DNA-DNA homology, primarily within biotypes 2 and 3.
- NDS strains exhibited minimal DNA homology with reference viridans streptococci.
Conclusions:
- The study confirms substantial genetic heterogeneity within nutritionally deficient streptococci (NDS).
- Current biotyping methods partially categorize NDS, but DNA relatedness highlights deeper genetic divisions.
- NDS represent a genetically diverse group, necessitating further investigation into their clinical significance.