An Unusual Cause of Recurrent Escherichia coli Meningitis in a Preterm Infant

A 1.69-kg, 33- + 4-weeks-old girl, is born to a 22-year-old gravida 6, para 1L1A4 mother by emergency cesarean delivery in view of previous lower-segment cesarean delivery in labor. Maternal history is significant for a positive lupus anticoagulant, for which she was on hydroxychloroquine. Apgar scores are 7 and 8 at 1 and 5 minutes of life, respectively. Baby receives continuous positive airway pressure support for 24 hours and is discharged on day 7 in stable condition. She remains on mixed feeding after discharge.At 36 days of life, she presents to the emergency department with irritability, poor feeding, and fever for 1 day. On evaluation, she appears lethargic with a nonfocal systemic examination. Sepsis screen result is negative (C-reactive protein [CRP], 5 mg/L; white blood cell [WBC] count, 11 500/mm3, 42% polymorphs). Lumbar puncture done in view of persistent fever reveals mild cerebrospinal fluid (CSF) pleocytosis (25 cells/mm3, 30% neutrophils) with normal protein (123.4 mg/dL) and glucose (41 mg/dL). CSF culture grows extended-spectrum β-lactamase (ESBL)–producing Escherichia coli. A blood culture and sensitivity test result is sterile. She is treated with a 14-day course of intravenous meropenem and is documented to have a normal head growth and neurosonography at discharge.Ten days postdischarge, she presents again with fever. Examination reveals generalized irritability with no other focal signs. Repeat evaluation yields a positive sepsis screen result (CRP, 157.5 mg/L; WBC, 4400/ mm3, 26% polymorphs). CSF analysis has 925 cells/mm3 (70% neutrophils), protein of 269 mg/dL, and blood glucose of 3 mg/dL. Blood and CSF culture results isolate E coli with the same sensitivity pattern. A urine culture result is sterile. Cranial and abdominal ultrasonography show no evidence of ventriculitis or pus collection. Lymphocyte subsets for immunodeficiency evaluation are within normal limits. The infant has respiratory syncytial virus pneumonia during this readmission requiring low-flow oxygen for 4 days. A 2D echocardiogram done in view of persistent tachycardia (∼160–180/min) on day 7 of hospital stay reveals a thrombus over tricuspid valve. She completes 21 days of intravenous meropenem and colistin (14 days after negative CSF culture result) according to sensitivity pattern. Thrombus resolution is noted after 2 weeks of subcutaneous enoxaparin.Four days after discharge, she presents again with fever. A repeat lumbar puncture yields 1150 cells/mm3 (60% neutrophils), CSF protein of 317.6 mg/dL, and blood glucose of 3 mg/dL, with a CSF culture result positive again for ESBL-producing E coli with an identical antibiogram. The blood culture result is sterile.Ventriculitis, cerebral abscess, empyema, or persistent parameningeal foci.Relapse secondary to delayed clearance of bacteria from CSF. In our case, CSF was found sterile after 1 week of antibiotic course during the second time.Predisposition to E coli infection, like urinary tract malformation with urinary tract infection, galactosemia, and poor antibody response to K1 capsular antigen of E coli in neonates. In our case, the Expanded Newborn Screening result was normal, and ultrasonography showed no urinary tract malformation.Primary immunodeficiency or anatomical conditions that provide continuous or intermittent bacterial access to the central nervous system.The main anatomical considerations include occult spinal dermal sinus tracts; anterior sacral meningoceles, often associated with the Currarino triad; congenital inclusion tumors such as dermoid or epidermoid with secondary infection; and rare neuroenteric fistulas that connect the gastrointestinal tract to the spinal canal. Less commonly, defects at the skull base or inner ear, such as congenital inner ear malformations, may lead to recurrent meningitis, but these typically involve organisms like Streptococcus pneumoniae or Haemophilus influenzae rather than gram-negative enteric bacteria.Primary immunodeficiency, particularly innate immune defects affecting Toll–interleukin-1 receptor pathways, also predispose to gram-negative infections.1 However, it has not been associated with neonatal E coli meningitis.2In our case, although initial examination of the back was grossly normal, meticulous re-examination with careful positioning and better lighting showed a tiny area of midline erythema as shown in Figure 1 in the lumbosacral region, a finding that had previously been dismissed as benign.Spinal magnetic resonance imaging (MRI) revealed a slender tract extending from the skin surface at L5 toward the posterior elements of S1, reaching up to the dural surface suggestive of a dorsal dermal sinus as shown in Figure 2. No associated intraspinal cyst or mass was seen. An MRI brain scan did not reveal any abscesses or ventriculitis.Small midline pits in the sacral region are common in newborns. Lesions situated higher than the gluteal crease, accompanied by erythema, discharge, or a palpable tract, raise concern for underlying spinal dysraphism.3 In this infant, the subtlety of the lesion allowed it to escape notice during 2 earlier admissions. The sinus tract acted as a persistent entry point for bacteria colonizing the diaper area. E coli is known to be associated with dermal sinus–associated meningitis.4Dorsal dermal sinus tracts arise from incomplete separation of the cutaneous and neural ectoderm during early embryonic development. The resulting tract may range from a shallow epithelial dimple to a deep channel that reaches the dura or even enters the intradural compartment. When the tract communicates directly with neural structures, it provides a potential route for pathogens to traverse into the subarachnoid space. Because these tracts may be narrow or intermittently obstructed, symptoms may fluctuate, and infections may occur episodically.The clinical presentation varies widely. Some infants remain asymptomatic until presenting with meningitis, as seen in this case; others develop local infection, drainage, or neurological deficits because of tethering of cord. Dermoid or epidermoid cysts may coexist with the tract and serve as chronic sources of infection or compression. The most frequently isolated pathogens in dermal sinus–related meningitis include E coli, Staphylococcus aureus, Proteus, and anaerobic organisms.5 Gram-negative recurrence, particularly with identical strains, is considered highly suggestive of this underlying pathology.Early recognition is crucial. Even tiny lumbosacral pits may represent significant anomalies, and meticulous physical examination using good lighting and proper infant positioning remains essential. In contrast, low sacral dimples located within or below the gluteal crease are generally benign and rarely associated with underlying spinal dysraphism. Overlooking such markers delays diagnosis, prolongs infectious risk, and increases the likelihood of neurological compromise.Neurosurgical exploration done after 72 hours of antibiotics confirmed a fibrous dermal sinus tract attached to the dura without intradural extension, as represented in Figure 3. The tract was completely excised, and the dural attachment was repaired. The infant completed 21 days of antibiotic course with carbapenems. CSF examination was repeated after 2 weeks of antibiotics, as it was close to surgical site and was sterile. The absence of intradural extension simplified the procedure and contributed to an excellent postoperative recovery. The baby had no neurological deficits on follow-up.A dermal sinus tract, although often appearing harmless, represents a form of spinal dysraphism that can lead to serious complications if left untreated. Preventing such outcomes requires prompt surgical management involving complete excision of the tract, intradural exploration, and correction of any associated anomalies.6Recurrent bacterial meningitis with the same organism in infancy should immediately raise suspicion for an underlying anatomical defect, even when prior evaluations appear normal. Dermal sinus tracts can serve as a direct conduit for ascending bacteria, making gram-negative organisms—particularly E coli—a characteristic microbiologic clue. MRI of the spine is the imaging modality of choice in such cases.Lumbosacral skin lesions, however small or seemingly benign, must be examined carefully in a well-lit setting with deliberate exposure of the gluteal cleft, as subtle dermal sinus tracts may be easily overlooked. Any such lesions should undergo ultrasonography imaging.Definitive surgical excision of the tract is essential to prevent infectious episodes and to avoid future complications, such as tethered cord or intradural inclusion cysts.American Board of Pediatrics Neonatal-Perinatal Content SpecificationUnderstand neural tube development disorders.Recognize various neonatal bacterial infections.