Identification of the high-virulence clone of group B streptococci by using a probe containing a putative aldolase gene.
A high-virulence clone (HVC) was proposed as causing much of the morbidity and mortality when a collection of group B Streptococcus (GBS) isolates was examined by multi-locus enzyme electrophoresis. HVC isolates could be further distinguished by their inability to grow at 40 degrees C, and a temperature-sensitive aldolase was identified as responsible for this characteristic. In the present study, the HVC was sought in a collection of 57 GBS isolates by hybridization with a probe containing a putative aldolase gene on genomic DNA restriction enzyme digests. Isolates were initially classified as HVC or non-HVC by their inability to grow at 40 degrees C. Three serotype III invasive isolates had the HVC control restriction/hybridization pattern. They were also unable to grow at 40 degrees C. The remaining 11 invasive and all carrier isolates showed a pattern identical to that of the non-HVC control. These results provide additional support for the existence of a highly virulent clonal group among serotype III isolates and suggest that hybridization with a probe containing the aldolase gene on DNA restriction enzyme digests can be an alternative method for identifying highly virulent isolates.
Palacios
Gerardo C
GC
Unidad de Investigación Médica en Epidemiología Clínica, Departamento de Infectología, Hospital de Pediatría, Instituto Mexicano del Seguro Social, México. palsaugc@terra.com.mx
Timmons
Brenda C
BC
Eskew
Elizabeth K
EK
Solórzano
Fortino
F
Mattingly
Stephen J
SJ
D015373:Bacterial Typing Techniques / Q000379:methods*; D015139:Blotting, Southern; D015342:DNA Probes; D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D004795:Enzyme Stability; D005634:Fructose-Bisphosphate Aldolase / Q000032:analysis* / Q000235:genetics*; D005838:Genotype; D006801:Humans; D009693:Nucleic Acid Hybridization; D010641:Phenotype; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013292:Streptococcus agalactiae / Q000145:classification* / Q000201:enzymology / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D013696:Temperature; D014774:Virulence
D015342:DNA Probes; D004269:DNA, Bacterial; D005634:Fructose-Bisphosphate Aldolase