Dynamic Pathology of Enteric Neural Network using Curcumin-assisted Multiphoton Laser Imaging in Hirschsprung Disease.

OBJECTIVE: In living tissue, it has been difficult to make microscopic-level observations without damaging the tissue. SUMMARY BACKGROUND DATA: We have invented a novel intravital fluorescent observation method (IFOM) for real-time tissue observation, combining multi-photon laser scanning microscopy (MPLSM) with curcumin vital staining (CVS-IFOM). The aim of this study was to use CVS-IFOM to analyze the enteric nervous system (ENS) in mice and human patients with hypoganglionosis and Hirschsprung disease. METHODS: In an initial viability study, we compared live ENS images from non-fluorescent C57BL6 mice stained with curcumin (n=5) and GFP mice (n=5) using MPLSM. We then explored CVS-IFOM for the live examination of resected colon tissues from one hypoganglionosis and three Hirschsprung disease patients. RESULTS: In the viability study, detailed ENS histological features were only observed in the curcumin-stained mice. In the hypoganglionosis patient, CVS-IFOM provided ENS details that were not visualized under H&E staining or calretinin immunohistochemistry, allowing the analysis of ENS size, neural bundle number, and neural cell number per plexus. In Hirschsprung disease patients, CVS-IFOM showed a gradual hypoplastic change in the ENS from the oral wedge to the anal wedge, detecting disproportionate changes in the ENS within the same intestinal level, supporting a circumferentially uneven distribution of the intestinal ENS. CONCLUSION: CVS-IFOM may be supportive for intraoperative pathological diagnosis during surgeries in Hirschsprung disease.

Promoter methylation levels of microRNA-124 in non-neoplastic rectal mucosa as a potential biomarker for ulcerative colitis-associated colorectal cancer in pediatric-onset patients.

PURPOSE: To determine the methylation level of the miR-124 promoter in non-neoplastic rectal mucosa of patients with pediatric-onset ulcerative colitis (UC) to predict UC-associated colorectal cancer (UC-CRC). METHODS: Between 2005 and 2017, non-neoplastic rectal tissue specimens were collected from 86 patients with UC, including 13 patients with UC-CRC; cancer tissues were obtained from the latter group. The methylation status of the miR-124 promoter was quantified using bisulfite pyrosequencing and compared between pediatric- and adult-onset UC patients. RESULTS: Patients with pediatric-onset UC experienced a significantly shorter disease duration than those with adult-onset UC. The levels of miR-124 promoter methylation in non-neoplastic rectal mucosa were positively correlated with the age at the diagnosis and duration of UC. The rate of increase in miR-124 methylation was accelerated in patients with pediatric-onset UC compared to those with adult-onset UC. Furthermore, the miR-124 methylation levels in non-neoplastic rectal mucosa were significantly higher in patients with UC-CRC than in those with UC alone (P = 0.02). A receiver operating characteristic analysis revealed that miR-124 methylation in non-neoplastic tissue discriminated between patients with pediatric-onset UC with or without CRC. CONCLUSION: miR-124 methylation in non-neoplastic rectal mucosa may be a useful biomarker for identifying patients with pediatric-onset UC who face the highest risk of developing UC-CRC.

Intraoperative surgical complications of open surgery for congenital diaphragmatic hernia: a multicenter, observational study in Japan.

PURPOSE: This study aimed to clarify surgical complications associated with open surgery for congenital diaphragmatic hernia (CDH). METHODS: We performed an exploratory data analysis of the clinical characteristics of surgical complications of neonates with CDH who underwent laparotomy or thoracotomy between 2006 and 2021. Data of these patients were obtained from the database of the Japanese CDH Study Group. RESULTS: Among 1,111 neonates with left or right CDH, 852 underwent open surgery (laparotomy or thoracotomy). Of these 852 neonates, 51 had the following surgical complications: organ injury (n = 48; 6% of open surgeries); circulatory failure caused by changes in the organ location (n = 2); and skin burns (n = 1). Injured organs included the spleen (n = 30; 62% of organ injuries), liver (n = 7), lungs (n = 4), intestine (n = 4), adrenal gland (n = 2), and thoracic wall (n = 2). Fourteen of the patients who experienced organ injury required a blood transfusion (2% of open surgeries). The adjusted odds ratio of splenic injury for patients with non-direct closure of the diaphragm was 2.2 (95% confidence interval, 1.1-4.9). CONCLUSION: Of the patients who underwent open surgery for CDH, 2% experienced organ injury that required a blood transfusion. Non-direct closure of the diaphragmatic defect was a risk factor for splenic injury.

Extraction of a metallic susceptor after accidental ingestion of the heated tobaccostick TEREA™: a case report.

BACKGROUND: Tobacco ingestion is widely known to cause nicotine toxicity, which may result in severe symptoms. Two heated tobacco sticks, called TEREA™ and SENTIA™, were launched in 2021 by Philip Morris International (New York, NY, USA), and their ingestion is associated with a risk of bowel injury because they contain a partially pointed metallic susceptor. However, this risk is not well known to the general public or healthcare providers. To increase awareness of this risk, we herein report a case involving extraction of a metallic susceptor after ingestion of the heated tobacco stick TEREA™. CASE PRESENTATION: A 7-month-old girl presented to the emergency department of a nearby hospital because she was suspected to have accidentally swallowed heated tobacco. Although she presented with no symptoms related to nicotine poisoning, abdominal X-ray examination revealed a metal object in her stomach. According to a statement released by the Japan Poison Information Center, the TEREA™ heated tobacco stick contains a metallic susceptor with a rectangular shape and sharp corners. The patient was transferred to our department because of the risk of bowel injury, and upper gastrointestinal endoscopy was performed. No cigarettes were found by endoscopic observation; however, a metallic susceptor was located in the second part of the duodenum. We grasped it with biopsy forceps and carefully removed it using an endoscope with a cap attached to the tip. The post-endoscopic course was uneventful. CONCLUSIONS: Some patients who ingest heated tobacco sticks might be exposed not only to the effects of nicotine but also to physical damage caused by a metallic susceptor. Infants and toddlers especially could swallow these sticks, therefore tobacco companies need to make the problem more public. Clinicians also should alert the problem, and pay attention to this risk in the clinical setting.

Preoperative myopenia and myosteatosis and their impact on postoperative complications in children with inflammatory bowel disease.

PURPOSE: To assess the severity of preoperative myopenia and myosteatosis in pediatric patients with inflammatory bowel disease (IBD) and examine their impact on postoperative complications. METHODS: The subjects of this retrospective study were 30 pediatric patients with IBD (22 with ulcerative colitis (UC) and 8 with Crohn's disease (CD)) and 67 age-matched controls. Preoperative body mass index (BMI), psoas muscle index (PMI), and intramuscular adipose tissue content were compared between the patient groups, to investigate their association with postoperative complications. RESULTS: BMI and PMI were significantly lower in the IBD patients than in the controls (p < 0.0001, p < 0.0001, respectively). CD was associated with significantly lower BMI and PMI (p = 0.01, p = 0.01, respectively) than UC. Intramuscular adipose tissue content was comparable between the IBD patients and the controls and between the UC and CD patients. There were no significant differences among the three indices in relation to the presence or absence of postoperative complications in patients with IBD. When limited to surgical site infection (SSI), only PMI was significantly lower in the patients with SSI than in those without SSI (p = 0.04). CONCLUSIONS: Although BMI and PMI were lower preoperatively in pediatric IBD patients than in controls, only myopenia seemed to affect the development of SSI.

Effects of Topical or Intravitreal Application of Anti-Vascular Endothelial Growth Factor on Density of Intestinal Blood Vessels of Mice.

Background and Objectives: Anti-vascular endothelial growth factor (anti-VEGF) therapy has become the first-line treatment for diabetic macular edema. However, it is still not clear whether anti-VEGF agents act on systemic blood vessels. The aim of this study is to determine whether a direct topical application or intravitreal injection of anti-VEGF will change the intestinal blood vessels of mice. Materials and Methods: C57BL/6 mice were laparotomied under deep anesthesia, and the blood vessels on the surface of the intestines were exposed, examined, and photographed through a dissecting microscope. Vascular changes were evaluated before and at 1, 5, and 15 min after the topical application of 50 µL of the different anti-VEGF agents onto the surface of the intestine (group S) or after the intravitreal injection (group V). The vascular density (VD) was determined for five mice in each group before and after 40 µg/µL of aflibercept (Af), or 25 µg/µL of bevacizumab (Be), or 10 µg/µL of ranibizumab (Ra) were applied. Endothelin-1 (ET1), a potent vasoconstrictor, was used as a positive control, and phosphate-buffered saline (PBS) was used as a control. Results: For group S, no significant changes were observed after PBS (baseline, 1, 5, and 15 min: 46.3, 44.5, 44.8, and 43.2%), Be (46.1, 46.7, 46.7, and 46.3%), Ra (44.7, 45.0, 44.7, and 45.6%), and Af (46.5, 46.2, 45.9, and 46.1%, repeated ANOVA) were applied topically. Significant decreases in the VD were observed after ET1 (46.7, 28.1, 32.1, and 34.0%, p < 0.05) was topically applied. For group V, no significant differences were observed for all anti-VEGF agents. Conclusions: The topical application or intravitreal injections of anti-VEGF agents do not cause a change in the VD of the intestinal vessels, which may be related to its safety.

Intestinal epithelial tight junctions and permeability can be rescued through the regulation of endoplasmic reticulum stress by amniotic fluid stem cells during necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) is one of the most severe gastrointestinal diseases affecting premature infants. It has been shown that NEC is associated with disrupted intestinal barrier and dysregulated endoplasmic reticulum (ER)-stress response. It has also been shown that stem cells derived from amniotic fluid (AFSC) rescued intestinal injury in experimental NEC. Herein, we hypothesized that the beneficial effects of AFSC in the injured intestine are due to the restoration of intestinal barrier function. We evaluated intestinal barrier function using an ex vivo intestinal organoid model of NEC. We found that AFSC restored the expression and localization of tight junction proteins in intestinal organoids, and subsequently decreased epithelial permeability. AFSC rescued tight junction expression by inducing a protective ER stress response that prevents epithelial cell apoptosis in injured intestinal organoids. Finally, we validated these results in our experimental mouse model of NEC and confirmed that AFSC induced sustained ER stress and prevented intestinal apoptosis. This response led to the restoration of tight junction expression and localization, which subsequently reduced intestinal permeability in NEC pups. These findings confirm that intestinal barrier function is disrupted during NEC intestinal injury, and further demonstrate the disruption can be reversed by the administration of AFSC through the activation of the ER stress pathway. This study provides insight into the pathogenesis of NEC and highlights potential therapeutic targets for the treatment of NEC.

A predictive scoring system for small diaphragmatic defects in infants with congenital diaphragmatic hernia.

PURPOSE: To develop a predictive score for small diaphragmatic defects in infants with congenital diaphragmatic hernia (CDH) for determining thoracoscopic surgery indication. METHODS: The Japanese CDH Study Group cohort was randomly divided into derivation (n = 397) and validation (n = 396) datasets. Using logistic regression, a prediction model and weighted scoring system for small diaphragmatic defects were created from derivation dataset and validated with validation dataset. RESULTS: Six weighted variables were selected: no hydramnios, 1 point; 1 min Apgar score of 5-10, 1 point; apex type of the lung (left lung is detected radiographically in apex area), 1 point; oxygenation index < 8, 1 point; abdominal nasogastric tube (tip of the nasogastric tube is detected radiographically in the abdominal area), 2 points; no right-to-left flow of ductus arteriosus, 1 point. In validation dataset, rates of small diaphragmatic defects for Possible (0-3 points), Probable (4-5 points), and Definite (6-7 points) groups were 36%, 81%, and 94%, respectively (p < 0.001). Additionally, sensitivity, specificity, positive predictive value, and C statistics were 0.78, 0.79, 0.88, 0.76, and 0.45, 0.94, 0.94, 0.70 for Probable and Definite groups, respectively. CONCLUSION: Our scoring system effectively predicted small diaphragmatic defects in infants with CDH.

The efficacy of the postnatal nasogastric tube position as a prognostic marker of left-sided isolated congenital diaphragmatic hernia.

PURPOSE: The prenatal diagnosis of the stomach position in congenital diaphragmatic hernia (CDH) has been a reliable prognostic factor, but few studies have focused on the postnatal position. We therefore evaluated the significance of the nasogastric (NG) tube position just after birth. METHODS: The Japanese CDH Study Group database enrolled 1037 CDH neonates over 15 years. In our multicenter retrospective study, 464 cases of left-sided isolated CDH with prenatal diagnoses were divided into two groups: NG tube below the diaphragm (BD; n = 190) or above the diaphragm (AD; n = 274). The primary outcome was the 90-day survival rate, and the secondary outcomes were mechanical ventilation duration, hospitalization duration, and recurrence rate. RESULTS: The BD group had a significantly higher 90-day survival rate (98.4 vs. 89.4%, p < 0.001), shorter mechanical ventilation (11 vs. 19 days, p < 0.001), shorter hospitalization (38 vs. 59 days, p < 0.001), and lower recurrence rate (p = 0.002) than the AD group. A multivariate analysis showed that BD (adjusted odds ratio, 3.68; 95% confidence interval 1.02-13.30) was a favorable prognostic factor for the 90-day survival. CONCLUSION: The assessment of the NG tube position revealed it to be a reliable prognostic factor of left-sided isolated CDH. Therefore, it should be included as a routine assessment.

The intestinal injury caused by ischemia-reperfusion is attenuated by amniotic fluid stem cells via the release of tumor necrosis factor-stimulated gene 6 protein.

Ischemia/reperfusion (I/R) is implicated in the pathogenesis of various acute intestinal injuries. Amniotic fluid stem cells (AFSC) are beneficial in experimental intestinal diseases. Tumor necrosis factor-induced protein 6 (TSG-6) has been shown to exert anti-inflammatory effects. We aimed to investigate if AFSC secreted TSG-6 reduces inflammation and rescues intestinal I/R injury. The superior mesenteric artery of 3-week-old rats was occluded for 90 minutes and green fluorescent protein-labeled AFSC or recombinant TSG-6 was injected intravenously upon reperfusion. AFSC distribution was evaluated at 24, 48, and 72 hours after I/R. AFSC and TSG-6 effects on the intestine were assessed 48 hours postsurgery. Intestinal organoids were used to study the effects of TSG-6 after hypoxia-induced epithelial damage. After I/R-induced intestinal injury, AFSC migrated preferentially to the ileum, the primary site of injury, through blood circulation. Engrafted AFSC reduced ileum injury, inflammation, and oxidative stress. These AFSC-mediated beneficial effects were dependent on secretion of TSG-6. Administration of TSG-6 protected against hypoxia-induced epithelial damage in intestinal organoids. Finally, TSG-6 attenuated intestinal damage during I/R by suppressing genes involved in wound and injury pathways. This study indicates that AFSC or TSG-6 have the potential of rescuing the intestine from the damage caused by I/R.

Doppler ultrasound assessment of splanchnic perfusion and heart rate for the detection of necrotizing enterocolitis.

PURPOSE: Monitoring disease progression is crucial to improve the outcome of necrotizing enterocolitis (NEC). A previous study indicates that intestinal wall flow velocity was reduced in NEC pups from the initial stages of the disease. This study aims to investigate whether splanchnic perfusion via the superior mesenteric artery (SMA) (i) is altered during NEC development and (ii) can be used as a monitoring tool to assess disease progression. METHODS: NEC was induced in C57BL/6 mice via gavage feeding of formula, hypoxia, and oral lipopolysaccharide, from postnatal day 5 (P5) to P9 (AUP: 32,238). Breastfed littermates served as controls. Doppler ultrasound (U/S) of bowel loops was performed daily. Intestinal wall perfusion was calculated as average flow velocity (mm/s) of multiple abdominal regions. Groups were compared using one-way ANOVA. RESULTS: The SMA flow velocity was not altered during the initial stage of NEC development, but become significantly reduced at P8 when the intestinal disease was more advanced. These changes occurred concomitantly with an increase in heart rate. CONCLUSIONS: NEC is associated with intestinal hypo-perfusion at the periphery and flow in the SMA is reduced during the later stages of disease indicating the presence of intestinal epithelium damage. This study contributes to understanding NEC pathophysiology and illustrates the value of Doppler U/S in monitoring disease progression.

Safety of double-balloon enteroscopy in postoperative pediatric patients.

BACKGROUND: The aim of the present study was to investigate the efficacy and safety of double-balloon enteroscopy (DBE) in postoperative pediatric patients. METHODS: This was a retrospective analysis of pediatric patients 18 years and younger referred to Mie University Hospital. Twenty procedures in 11 children occurred postoperatively; 29 children (42 procedures) had not undergone surgery. RESULTS: Among postoperative patients, five DBE procedures were performed via the oral route, 12 via the anal route, and three via a stomal route. Among nonoperative patients, 14 DBE procedures were performed via the oral route and 28 via the anal route. Four postoperative patients and two nonoperative patients had difficult pleating via the transanal route because of adhesions or thickening of the intestinal wall resulting from inflammation (P = 0.02). Excluding patients with stenosis, the mean length of endoscopic insertion for transanal procedures was significantly shorter among postoperative patients than among nonoperative patients (73.6 cm vs 160.5 cm, P < 0.01). There were no major complications in either group. CONCLUSIONS: Insertion difficulty was encountered in postoperative pediatric patients. However, our findings indicate that DBE is a safe procedure in postoperative pediatric patients.

Risk factors and intraoral breast milk application for methicillin-resistant Staphylococcus aureus colonization in surgical neonates.

BACKGROUND: Our previous study identified methicillin-resistant Staphylococcus aureus (MRSA) colonization as an independent risk factor for neonatal surgical site infection. Here we introduce intraoral breast milk application (IBMA) during a fasting state to prevent MRSA colonization. We aimed to evaluate both the risk factors for MRSA colonization and the efficacy of IBMA in neonatal surgical patients. METHODS: A retrospective review was performed using admission data from 2007 to 2016. Neonatal patients who underwent surgery and were tested periodically for MRSA colonization were evaluated for an association between MRSA colonization and perinatal or perioperative factors. RESULTS: The overall incidence of MRSA colonization for the 159 patients enrolled in this study was 16.4%. Univariate analysis showed that MRSA colonization was significantly more frequent in the following patients: those with Down syndrome, those admitted on their day of birth, those in need of fasting immediately after birth, and those not receiving IBMA. Multivariate analysis showed that comorbid Down syndrome was an independent risk factor (hazard ratio: 4.6; 95% confidence interval: 1.2-19.5, P = 0.03) and implementation of IBMA was an independent preventive factor for MRSA colonization (hazard ratio: 0.4; 95% confidence interval: 0.1-0.9, P = 0.04). MRSA-positive patients admitted significantly earlier and stayed longer preoperatively than MRSA-negative patients. CONCLUSIONS: In neonates undergoing surgery, and patients with Down syndrome, early diagnosis after birth and a long waiting period before operation may be associated with MRSA colonization. Intraoral breast milk application may be beneficial for preventing MRSA colonization.

The effect of pre- and post-remote ischemic conditioning reduces the injury associated with intestinal ischemia/reperfusion.

PURPOSE: Midgut volvulus is associated with intestinal ischemia/reperfusion (IR) injury and can progress to severe intestinal damage. Remote ischemic conditioning (RIC) reduces IR-induced injury in distant organs. The aim of this study was to investigate whether RIC protects the intestine from IR injury. METHODS: We investigated intestinal IR injury in 3 weeks old SD rats. Animals underwent: (i) sham laparotomy, (ii) intestinal IR injury, (iii) intestinal IR + RIC during ischemia, or (iv) intestinal IR + RIC after reperfusion. Intestinal IR injury was achieved by 45 min occlusion of superior mesenteric artery followed by de-occlusion. RIC was administered via four cycles of 5 min of hind limb ischemia followed by 5 min reperfusion. Animals were sacrificed 24 h after surgery and the ileum was harvested for evaluation. RESULTS: Intestinal injury was present after IR. However, this injury was reduced in both IR + RIC groups. Expression of inflammatory cytokine IL6 was lower in IR + RIC groups compared to IR alone. Carbonyl protein was also significantly lower in IR + RIC compared to IR, indicating lower oxidative stress in both IR + RIC groups. CONCLUSION: Remote ischemic conditioning attenuated intestinal injury, inflammation, and oxidative stress in experimental intestinal ischemia/reperfusion injury. Remote ischemic conditioning may be useful in children with midgut volvulus to reduce the intestinal injury. LEVEL OF EVIDENCE: Experimental study. TYPE OF STUDY: Animal experiment.

Predictors for Pouchitis After Ileal Pouch-Anal Anastomosis for Pediatric-Onset Ulcerative Colitis.

BACKGROUND: The predictive factors for the development of pouchitis after ileal pouch-anal anastomosis (IPAA) in pediatric-onset ulcerative colitis (UC) have not been well investigated. The present study aimed to determine the predictive factors for the development of pouchitis after IPAA in the pediatric UC population. METHODS: The data from 54 patients with pediatric-onset UC who underwent IPAA in Mie University Hospital between 2000 and 2017 were retrospectively reviewed. A modified pouchitis disease activity index of ≥5 was defined as pouchitis. Potential preoperative, intraoperative, and postoperative predictors for pouchitis including various demographic and clinical variables were analyzed using Cox regression analysis, Students' t-tests, Mann-Whitney U tests, and Kaplan-Meier curves. The optimal cutoff value for continuous variables was determined using the receiver operating characteristic curve analysis. RESULTS: Pouchitis was identified in 17 (31.5%) patients within 5 y of follow-up. In multivariable analysis, the independent predictors for pouchitis were preoperative cumulative steroid dose of >10,000 mg (P = 0.0056) and >65% neutrophils just before IPAA (P = 0.032). Multivariate analysis revealed that the independent predictors of pouchitis were a total steroid dose of >10,000 mg (P = 0.0002) and a neutrophil percentage of >65% (P = 0.0078). No patient for whom both of these independent predictors were negative developed pouchitis, whereas >40% of patients who had one or both predictors developed pouchitis. CONCLUSIONS: In pediatric patients with UC, the predictive factors for pouchitis development are a greater cumulative total dose of steroids and a greater percentage of neutrophils before IPAA.

Are prophylactic anti-reflux medications effective after esophageal atresia repair? Systematic review and meta-analysis.

PURPOSE: Gastroesophageal reflux after surgical repair of esophageal atresia (EA) can be associated with complications, such as esophageal stricture. Recent guidelines recommend prophylactic anti-reflux medication (PARM) after EA repair. However, the effectiveness of PARM is still unclear. The aim of this study was to review evidence surrounding the use of PARM in children operated for EA. METHODS: We performed a systematic review and meta-analysis. We searched Medline, EMBASE, and the Cochrane Databases from inception until the end of 2016 for comparative studies of PARM versus no PARM (control). Primary outcome was postoperative esophageal stricture. Quality of evidence was assessed using GRADE system. RESULTS: We identified four observational studies that focused on esophageal stricture as an outcome. A total of 362 patients were included in meta-analysis. There was no significant difference in esophageal stricture rates between PARM and control (OR = 1.14; 95% CI = 0.61-2.13; p = 0.68; I2 = 38%). The quality of the evidence was very low, due to lack of precision as a consequence of small study sizes. CONCLUSIONS: Our results indicate that PARM does not reduce the incidence of esophageal stricture after EA repair. Future well-controlled prospective studies are needed to obtain higher quality evidence.

Impact of relationship between the stoma site and the primary incision on occurrence of laparotomy wound infection in contaminated or dirty wound operations in neonates.

BACKGROUND: In neonatal surgical patients requiring an enterostomy, there is no definitive recommendation regarding the ideal enterostomy location: at the edge of the primary incision or at a different incision. METHODS: We retrospectively reviewed 2005-2017 administration data in our institution. All neonatal patients who underwent contaminated or dirty wound laparotomy and enterostomy construction were evaluated regarding the enterostomy location, occurrence of postoperative incisional surgical-site infection (SSI) at the primary incision, and stoma-related complications. RESULTS: Patients were divided into two groups based on stoma location: at the primary incision (the same incision group: SI group, n = 16) or at another incision (different incision group: DI group, n = 23). We performed 2 jejunostomies, 13 ileostomies, and 1 colostomy in the SI group, and 4 jejunostomies, 18 ileostomies, and 1 colostomy in the DI group. One of 16 patients (6.3%) in the SI group and 2/23 patients (8.7%) in the DI group experienced superficial incisional SSI, with comparable SSI incidence between groups (p = 0.78). Every SSI did not result in stoma-related complications. CONCLUSIONS: Although the enterostomy location did not influence the incidence of laparotomy wound infection in this study, prospective studies are mandatory to fully assess the safety of enterostomy construction at the edge of the primary incision.

Contaminated or dirty wound operations and methicillin-resistant Staphylococcus aureus (MRSA) colonization during hospitalization may be risk factors for surgical site infection in neonatal surgical patients.

PURPOSE: Establishment of evidence-based best practices for preventing surgical site infection (SSI) in neonates is needed. SSI in neonates, especially those with a low birth weight, is potentially life-threatening. We aimed to identify risk factors associated with SSI in neonates. METHODS: A retrospective review was performed using 2007-2016 admission data from our institution. Neonatal patients who were admitted to the neonatal intensive care unit and underwent surgery were evaluated for a relationship between development of SSI and perinatal or perioperative factors and methicillin-resistant Staphylococcus aureus (MRSA) colonization during hospitalization. RESULTS: One hundred and eighty-one patients were enrolled in this study. Overall SSI incidence was 8.8%. Univariate analysis showed that SSI was significantly more frequent in both patients with contaminated or dirty wound operations and patients with MRSA colonization during hospitalization. Both of these factors were identified as independent risk factors for SSI by multivariate analysis [hazard ratio (HR): 6.1, 95% confidence interval (CI) 2.0-19.9; HR: 3.3, 95% CI 1.1-10.4, respectively]. CONCLUSIONS: This study identified contaminated or dirty wound operations and MRSA colonization during hospitalization as risk factors for SSI in neonates. MRSA colonization may be a preventable factor, unlike previously reported risk factors.