Occult bacteremia with group B streptococci in an outpatient setting

We undertook this study to determine the relative frequency of occult bacteremia with group B streptococci (GBS) and to define the clinical features of infants with occult bacteremia attributable to GBS at the time of initial clinical contact.

The logs of the microbiology laboratory were reviewed for blood and cerebrospinal fluid isolates of GBS from 1982 to 1996. Records of patients identified with GBS were abstracted. Patients were classified as having occult bacteremia if GBS were isolated from their blood and they seemed nontoxic and had no apparent clinical or laboratory evidence of focal infection. All other patients were diagnosed with sepsis, meningitis, or nonmeningeal foci.

We reviewed the medical records of 147 children with GBS and identified 108 outpatients, including 47 (44%) with occult bacteremia, 42 (39%) with meningitis, 11 (10%) with nonmeningeal foci, and 8 (7%) with sepsis. Compared with patients with sepsis or focal infections, those with occult bacteremia were older (61.1 vs 39.1 days) and had slightly, although not significantly, higher white blood cell (WBC) counts (13 280 +/- 6854 vs 10 688 +/- 8574), but similar degrees of fever. Among the 47 patients with occult bacteremia, none died, as compared with 2 of 61 with serious infections, and fewer had neurologic sequelae (0/47 vs 11/61). Patients with occult bacteremia >90 days of age generally had temperatures >39 degreesC (9/11, mean 39.3 degreesC) and WBC counts >15 000/mm3 (7/10, mean 19 070/mm3), both of which differed significantly compared with those who were <90 days of age. Thirty of the 47 patients with occult bacteremia received intravenous antibiotics and recovered. One of 8 patients discharged without antibiotics and none of 8 with antibiotics developed a focal complication; 1 discharged patient was lost to follow-up.

Almost one-half of the children with GBS disease beyond the immediate neonatal period had occult bacteremia. Among 8 untreated patients with bacteremia, 1 developed a focal complication. Although the small proportion of children with GBS occult bacteremia who were >90 days of age usually had the risk factors of temperature >39 degrees C and WBC >15 000/mm3, as seen with occult bacteremia attributable to other organisms, the majority of the patients who were younger did not have a characteristic clinical syndrome. Prevention of sequelae in these young infants will require a low threshold for diagnosis and treatment.