Background Streptococcal toxic shock syndrome (STSS) is a rare, severe manifestation of a Streptococcus pyogenes infection.Recently, streptococcal toxic shock-like syndrome (STSLS) has been described in relationship to other streptococcal infections, including Streptococcus agalactiae, which is much less common than S.pyogenes.Twenty-two cases of S.agalactiae STSLS have been reported, all in adults.Until recently, STSLS was considered to be rare in children.STSS resulting from an S.pyogenes infection has been attributed to the presence of superantigens, whereas the pathogenesis of 'toxic shock' in S.agalactiae infections is less clear.Methods We reported a case of a 6-month-old infant with S.agalactiae STSLS.Clinical feature and treatment progress were analyzed retrospectively.We discuss the possible role of toxins in the case.We conducted a brief review of the 22 reported adult cases.Results Our patient had no known risk factors for Group B STSLS.He was a previously healthy child, which might differentiate the features of STSLS in children and adults.Irritability and restlessness were early manifestations in the pediatric patient.In contrast with the initial nonspecific clinical picture in the pediatric case, the rapid clinical deterioration with the development of shock and signs of organ dysfunction was remarkable.The case was characterized with nervous system abnormality, DIC and kidney impairment.No skin rash was observed.We identified only 22 documented cases in English in the literature.All of the documented patients were adults.The median age was 54 years.Sixteen cases were associated with medical problems.Four patients had previously been healthy, and two cases were unexplained.In addition to fever, the initial clinical picture for Group B STSLS was markedly variable.Pain and edema at the infection site were obvious in the 13 patients with necrotizing fasciitis, cellulitis or a skin abscess.A red rash was observed in three patients.An influenza-like syndrome characterized by a nonproductive cough, chills, myalgia, malaise, nausea, vomiting, diarrhea, and headache was observed in four patients.In our case, the S.pyogenes superantigen genes, ssa, SMEZ, speA, speB, speC, speG, speH, speI and speJ were not detected by PCR.Molecular typing of the isolates from this case identified them as serotype Ⅲ, subtype 3, which is the identical serosubtype, Ⅲ-3, as that of the known genome strain, NEM316, which caused a fatal neonatal case of septicemia.PCR confirmed that the isolates possessed cylE, which is part of the cyl gene complex that encodes for the β-hemolysin/cyolysin (β-h/c) virulence factor.We observed that S.agalactiae exhibited significantly higher orange pigment production than 12 diverse control strains.Conclusions This child tragically died from Group B STSLS, and the effects of hemolysin and other toxins are not excluded as causes of death.Further clarification of the role of toxins in S.agalactiae infections would facilitate the case definition of STSS, epidemiological studies and the investigation of treatment modalities, such as intravenous immunoglobulin.Although it rarely encountered in most Emergency Department and ICU, STSS frequently leads to a lethal outcome.Pediatricians and Emergency Department physicians must be aware of this catastrophic disease possibility and immediately initiate aggressive treatment when suspected.