Three fatal cases of invasive serotype VI group B streptococcal infection.

Serotype VI group B Streptococcus (GBS) has been almost frequently isolated among colonizing strains of pregnant women in Japan, but the clinical features and prognosis, when a patient is invasively infected, are largely unknown. We report, for the first time, three cases of fatal infection caused by serotype VI GBS; two cases were middle-aged men with necrotizing fasciitis/cellulitis, sepsis, and toxic shock syndrome with poorly controlled diabetes as underlying conditions; and one was a premature infant with intrauterine infection. Our results indicated that type VI GBS is pathogenic for humans not only in fetuses but also adults, and has the ability to be fatal, at least in selected patients.