Early‐infant Streptococcus gallolyticus sepsis linked to congenital splenic dysfunction: A three‐case series

Streptococcus gallolyticus, particularly subspecies pasteurianus, is increasingly recognized as a cause of sepsis and meningitis in neonates and young infants.1 Reported pediatric risk factors include neonatal age, prematurity, maternal colonization, and prolonged rupture of membranes with chorioamnionitis.2 S. gallolyticus produce a polysaccharide capsule,3 and hyposplenism predisposes to invasive encapsulated bacterial infection.4 However, an association between congenital splenic abnormalities and S. gallolyticus infection in infancy has not been established1; only a single case has been reported in a splenectomized adult.5 This gap may delay diagnosis of splenic disorders and prophylaxis, including antibiotics and vaccinations, to prevent future life-threatening infections.4 We encountered three term infants with invasive S. gallolyticus bloodstream infection; subsequent evaluation identified congenital splenic disorders: hypoplastic spleen, polysplenia with functional hyposplenism, and isolated congenital asplenia. This is the first infant case series suggesting an association between S. gallolyticus sepsis and congenital hyposplenic states. Clinical data are summarized in Figure 1 and Table S1. All patients survived; however, two required intensive care, and one developed secondary neurologic injury with profound shock and hypoglycemia. In Case 1, a 79-day-old girl presented with grunting respirations, shock, and impaired consciousness. Initial tests showed severe hypoglycemia, leukopenia, and metabolic acidosis; a peripheral smear showed Howell-Jolly bodies (Figure 1a). Cerebrospinal fluid (CSF) analysis was normal and CSF cultures were negative. She required intensive care, including mechanical ventilation and vasopressors. After blood cultures grew S. gallolyticus, empiric antibiotic therapy was de-escalated to ampicillin for 14 days. Abdominal ultrasonography did not visualize the spleen (Figure 1b), and magnetic resonance imaging (MRI) identified a hypoplastic spleen (Figure 1c). Brain MRI showed bilateral subdural hematomas and signal abnormalities, and her development remained age-appropriate at 10 months. In Case 2, a 36-day-old girl presented with fever and lethargy. Laboratory testing showed leukopenia; a peripheral blood smear revealed no Howell-Jolly bodies. CSF was unremarkable. Empiric antibiotic therapy was started, and blood cultures grew S. gallolyticus, followed by ampicillin for 14 days. Abdominal ultrasonography revealed a nodular, hypoechoic splenic structure; subsequent MRI confirmed polysplenia (Figure 1d). Technetium-99m tin colloid scintigraphy after discharge showed reduced splenic uptake, consistent with functional hyposplenism (Figure 1e). She remained well at 3 years. In Case 3, a 15-day-old boy presented with fever and rapidly progressive sepsis. Laboratory findings showed leukopenia and Howell-Jolly bodies; lumbar puncture was not performed because of clinical instability. He required ventilation and vasopressors. Empiric antibiotic therapy was started at meningitic doses. After blood cultures grew S. gallolyticus, antibiotics were transitioned to ampicillin for a total of 21 days. Follow-up lumbar puncture was attempted but could not be completed due to technical challenges. Abdominal ultrasonography and contrast-enhanced computed tomography did not visualize the spleen (Figure 1f). In the absence of cardiac malformations or visceral heterotaxy, he was diagnosed with isolated congenital asplenia. His development was age-appropriate at 2 years, and ultrasonography of first-degree relatives showed normal-sized spleens. Although larger studies have not yet established a strong association between S. gallolyticus and asplenia,1, 2 these cases suggest that invasive S. gallolyticus infection in early infancy should prompt evaluation for congenital splenic dysfunction. When S. gallolyticus is isolated from a sterile site, we suggest reviewing a peripheral smear for Howell-Jolly bodies and performing abdominal ultrasonography. While Howell-Jolly bodies are a classic marker, their sensitivity for detecting splenic dysfunction is limited compared to other modalities.4 If ultrasonography is inconclusive, MRI or computed tomography can confirm hypoplasia or absence. Radionuclide imaging (e.g., technetium-99m tin colloid scintigraphy) is useful for quantitative assessment but should be reserved for unresolved clinical uncertainty. Because isolated congenital asplenia can be familial, ultrasonographic screening of first-degree relatives should be considered.4 In infants with confirmed asplenia or hyposplenism, preventive care is essential, including caregiver education, prompt evaluation of febrile illness, antimicrobial prophylaxis, and age-appropriate vaccinations.4 Cases 1 and 3 started daily amoxicillin prophylaxis; Case 3 received a quadrivalent meningococcal conjugate vaccine at age 2, and vaccination is planned for Case 1 when eligible. Our limitation is a small sample size; we cannot estimate how often S. gallolyticus infection is the first presentation of congenital splenic disorders. Larger multicenter studies are needed to delineate the prevalence and clinical spectrum of this association. AN and DK conceptualized the study and performed the literature search. AN drafted the initial manuscript. AN, DK, TO, and YT collected and curated the clinical data. All authors were involved in the clinical management of the patients, including diagnosis and treatment decisions. All authors contributed to revising the manuscript and approved the final version. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. The authors declare no conflict of interest. Informed consent was obtained from the parents/guardians of all patients. Publication consent was obtained from the patients and guardians. Data sharing is not applicable to this article as no datasets were generated or analyzed during the current study. Table S1. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.