A Retrospective Case Control Study Examining Procalcitonin as a Biomarker for Necrotizing Enterocolitis.

Background: Procalcitonin (PCT) is a biomarker for sepsis, but its utility has not been investigated in necrotizing enterocolitis (NEC). Necrotizing enterocolitis is a devastating multisystem disease of infants that in severe cases requires surgical intervention. We hypothesize that an elevated PCT will be associated with surgical NEC. Patients and Methods: After obtaining Institutional Review Board (IRB) approval (#12655), we performed a single institution retrospective case control study between 2010 and 2021 of infants up to three months of age. Inclusion criteria was PCT drawn within 72 hours of NEC or sepsis diagnosis. Control infants had a PCT drawn in the absence of infectious symptoms. Recursive partitioning (RP) identified PCT cutoffs. Categorical variable associations were tested using Fisher exact or χ2 tests. Continuous variables were tested using Wilcoxon rank sum test, Student t-test, and Kruskal-Wallis test. Adjusted associations of PCT and other covariables with NEC or sepsis versus controls were obtained via multinomial logistic regression analysis. Results: We identified 49 patients with NEC, 71 with sepsis, and 523 control patients. Based on RP, we selected two PCT cutoffs: 1.4 ng/mL and 3.19 ng/ml. A PCT of ≥1.4 ng/mL was associated with surgical (n = 16) compared with medical (n = 33) NEC (87.5% vs. 39.4%; p = 0.0015). A PCT of ≥1.4 ng/mL was associated with NEC versus control (p < 0.0001) even when adjusting for prematurity and excluding stage IA/IB NEC (odds ratio [OR], 28.46; 95% confidence interval [CI], 11.27-71.88). A PCT of 1.4-3.19 ng/mL was associated with both NEC (adjusted odds ratio [aOR], 11.43; 95% CI, 2.57-50.78) and sepsis (aOR, 6.63; 95% CI, 2.66-16.55) compared with controls. Conclusions: A PCT of ≥1.4 ng/mL is associated with surgical NEC and may be a potential indicator for risk of disease progression.

Apical-Out Enteroids as an Innovative Model for Necrotizing Enterocolitis.

INTRODUCTION: Necrotizing enterocolitis (NEC) is a gastrointestinal disease of premature neonates. We previously validated a NEC enteroid model derived from human infant intestinal tissue. Typical enteroid configuration is basolateral-out (BO) without direct access to the luminal (apical) surface. Apical access is necessary to allow physiologic comparison of pathogen interaction with the intestinal epithelial barrier. We hypothesize that apical-out (AO) enteroids will provide a relevant NEC model to study this relationship. METHODS: Following the institutional review board approval (#11610-11611), neonatal intestinal tissue was collected from surgical specimens. Stem cells were collected; enteroids were generated and grown to maturity in BO conformation then everted to AO. Enteroids were untreated or treated for 24 h with 100 µg/mL lipopolysaccharide and hypoxia. Protein and gene expression were analyzed for inflammatory markers, tight junction (TJ) proteins and permeability characteristic of NEC. RESULTS: Apical TJ protein zonula occludens-1 and basolateral protein ß-catenin immunofluorescence confirmed AO configuration. Treated AO enteroids had significantly increased messenger RNA (P = 0.001) and protein levels (P < 0.0001) of tumor necrosis factor-α compared to controls. Corrected total cell fluorescence of toll-like receptor 4 was significantly increased in treated AO enteroids compared to control (P = 0.002). Occludin was found to have significantly decreased messenger RNA in treated AO enteroids (P = 0.003). Expression of other TJ proteins claudins-1, -4 and zonula occludens-1 was significantly decreased in treated AO enteroids (P < 0.05). CONCLUSIONS: AO enteroids present an innovative model for NEC with increased inflammation and gut barrier restructuring. This model allows for a biologically relevant investigation of the interaction between the pathogen and the intestinal epithelial barrier in NEC.

Methicillin-resistant Staphylococcus aureus enterocolitis in a 16-month-old boy: a case report.

BACKGROUND: Methicillin-resistant Staphylococcus aureus enterocolitis is a rare disease that typically affects immunocompromised adults. Most cases of pediatric enterocolitis are caused by Gram-negative bacteria, Gram-positive Clostridiodes difficile, or viruses. This is the first published case report of a toddler with methicillin-resistant Staphylococcus aureus enterocolitis. CASE PRESENTATION: A 16-month-old non-Hispanic White boy with no past medical or psychosocial history initially presented to the emergency room with abdominal pain and emesis. Past family history was pertinent only for his father having a history of constipation. He was diagnosed with intussusception and underwent successful contrast reduction on hospital day 0. The following day, the patient had recurrent symptoms and a repeat contrast enema showed no evidence of recurrent intussusception. A computed tomography scan was obtained, which was concerning for possible recurrence with compromised bowel. He was taken to the operating room for operative reduction and underwent an ileocecetomy with primary handsewn end-to-end anastomosis. His postoperative course was complicated by an anastomotic leak on hospital day 6 necessitating reoperation and creation of an end ileostomy with mucous fistula. He received intravenous metronidazole, ceftriaxone, and ceftazidime antibiotics during his hospital course. On postoperative day 12, the patient developed a sudden increase in ileostomy output, and stool cultures were obtained. His symptoms persisted despite diet modifications, stopping antibiotics, and initiating loperamide. Three days later, stool cultures resulted negative for Escherichia coli, Salmonella, Shigella, Campylobacter species, and Clostridiodes difficile but were positive for methicillin-resistant Staphylococcus aureus. The patient was started on a 10-day course of oral vancomycin and discharged home in good condition 4 days later. After 12 weeks, the patient underwent reversal of the ostomy and is doing well at the 1 month postoperative follow-up, now 5 months from his initial surgery. CONCLUSIONS: To our knowledge, this is the first published report of a toddler being diagnosed with methicillin-resistant Staphylococcus aureus enterocolitis. Because methicillin-resistant Staphylococcus aureus enterocolitis is rare and has overlapping symptoms with more common gastrointestinal pathologies, it is often misdiagnosed. When a patient presents with diarrhea or high ostomy output along with fecal cultures negative for Clostridiodes difficile and other common pathogenic agents, methicillin-resistant Staphylococcus aureus should be considered.