Temperature-sensitive mutants of Streptococcus pneumoniae. I. Preparation and characterization in vitro of temperature-sensitive mutants of type I S. pneumoniae.

Abstract

After exposure of type I Streptococcus pneumoniae to nitrosoguanidine, 13 temperature-sensitive (ts) mutants were selected that were restricted in capacity to form colonies on blood agar at 38 C. Whereas colony formation by the type I parent (ts+) was unaffected by a temperature of as high as 39 C, the ts mutants exhibited a spectrum of temperature sensitivity in which colony formation was inhibited significantly at 36 C, 37 C, 38 C, or 39 C. Growth of ts mutants at 38 C in broth was reduced or delayed relative to that of ts organisms under identical conditions. In general, there was a direct correlation between degree of temperature sensitivity and genetic stability. Mutants grown at a permissive temperature resembled the ts+ type I parent in colonial morphology and properties of alpha-hemolysis, bile solubility, optochin sensitivity, and antibiotic sensitivity. Moreover, in vitro studies indicated that the mutants retained capsules of immunochemically reactive type I capsular polysaccharide.

• Authors: C M Helms, M B Grizzard, B Prescott, L Senterfit, S Urmacher, G Schiffman, R M Chanock
• Journal: The Journal of infectious diseases (J Infect Dis) Vol. 135 Issue 4 Pg. 582-92 (Apr 1977) ISSN: 0022-1899 [Print] United States
• PMID: 16064 (Publication Type: Journal Article)

Chemical References

• Culture Media
• Nitrosoguanidines
• Penicillins
• Erythromycin

Topics

• Bile
• Binding Sites, Antibody
• Culture Media
• Erythromycin
• Mutation (drug effects)
• Nitrosoguanidines (pharmacology)
• Penicillin Resistance
• Penicillins
• Solubility
• Streptococcus pneumoniae (isolation & purification)
• Temperature