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Background The etiology of neonatal sepsis is often not identified. Molecular methods can identify pathogens that culture-based methods miss. Most cases of neonatal sepsis globally are treated empirically per WHO guidelines with intravenous ampicillin and gentamicin, which may not be the best regimen for all pathogens. Methods We prospectively enrolled 800 neonates presenting with signs of sepsis to two Ugandan hospitals. Blood and cerebrospinal fluid were subjected to 16S rRNA sequencing, which identified Paenibacillus thiaminolyticus in 33/800 (4%) neonates. We confirmed the presence of P. thiaminolyticus by quantitative polymerase chain reaction (PCR). We describe neonatal and birth characteristics, presenting signs, and 12-month developmental outcomes for neonates with paenibacillosis. We performed antibiotic susceptibility testing and genomic analyses on three clinical isolates successfully grown in the laboratory. Results Neonates presented at a median age of 3 (1, 7) days. Fever (86%), irritability (78%) and seizures (52%) were common presenting signs (Figure). Most neonates were born vaginally (73%) at a medical facility (79%). Twelve (36%) had an adverse outcome: 5 (15%) neonates died; 4 (14%) survivors developed postinfectious hydrocephalus and three (9%) additional survivors had neurodevelopmental impairment. All three isolates were resistant to vancomycin, two were resistant to penicillin and ampicillin and one was unlikely to be sensitive to ceftriaxone; all were susceptible to gentamicin and meropenem. The genomes of all three strains contained multiple beta-lactamase genes and a cluster of genes that encodes a type IV pilus. Clinical signs at presentation for neonates with good and poor outcomes followng paenibacillosis Conclusion Molecular methods such as 16S rRNA sequencing and PCR can be used to improve the identification of pathogens causing neonatal sepsis. Paenibacillosis is an important emerging cause of neonatal sepsis in Uganda and is likely an underrecognized cause of postinfectious hydrocephalus in the region and possibly elsewhere. Antibiotics commonly used for neonatal sepsis may be inadequate for the treatment of paenibacillosis. Additional studies to understand the pathophysiology and optimal treatment of this novel infection are urgently needed to prevent neonatal mortality and morbidity including postinfectious hydrocephalus. Disclosures Jessica E. Ericson, MD, MPH, Abbvie: Advisor/Consultant Abhaya Kulkarni, MD, MSc, PhD, Medtronic: Advisor/Consultant.

Pediatric hemispherectomy is a technically demanding procedure with significant risk. There are relatively few opportunities for surgeon trainees to gain confidence in this nuanced surgery solely through traditional apprenticeship prior to independent practice. Surgeon confidence has been linked to better intraoperative performance and surgical simulation has, according to literature, resulted in improved surgeon confidence. This manuscript measures the effect of epilepsy simulation on the procedural confidence of neurosurgical trainees as a marker of future improved intraoperative performance.Eleven neurosurgery residents and fellows were allowed to practice on a novel hemispherectomy simulator. Pre- and post-simulation procedural confidence was measured using a 10-item questionnaire, with total scores ranging from 10 (least confident) to 50 (most confident). Matched pair t-testing was performed to determine participant mean difference between the pre- and post-procedural data sets.The assessment tool bore a high reliability coefficient (Cronbach's α = 0.93). The procedural confidence of all the study participants increased following simulation (p value 0.001). The overall mean increase in confidence was 7.2 ± 4.0 (mean ± standard deviation), 7.5 ± 4.7 among fellows and 6.8 ± 3.6 among residents. Procedural confidence values were higher among the fellows (26.9 ± 8.1) compared to the residents (19.0 ± 7.4). This difference in means was statistically significant (p value 0.03). A positive association was calculated between the perceived confidence and the postgraduate year of training (p value 0.005, r = 0.57).The hemispherectomy simulator moderately improves perceived confidence among neurosurgical trainees and may augment pre-operative surgical practice opportunities.

OBJECTIVE The objective of this study was to describe the management of hydrocephalus in a cohort of pediatric patients with germinoma. METHODS The authors conducted a retrospective chart review of patients with germinoma and symptomatic hydrocephalus treated at the Hospital for Sick Children between 2002 and 2020. Descriptive data included tumor location, CSF diversion procedure (external ventricular drain [EVD], endoscopic third ventriculostomy [ETV], ventriculoperitoneal [VP] shunt) and outcomes. The frontooccipital horn ratio (FOR) method was used to determine the presence of ventriculomegaly. RESULTS Of 39 patients with germinoma, 22 (73% male) had symptomatic hydrocephalus at diagnosis (11 pineal, 4 suprasellar, and 7 bifocal). Management of hydrocephalus included EVD (n = 5, 22.7%), ETV (n = 5, 22.7%), and combination ETV and EVD (n = 7, 31.8%), whereas 5 patients (22.7%) did not undergo surgical intervention. The median FOR at diagnosis was 0.42 (range 0.38–0.58), which correlated with moderate to severe ventriculomegaly. Carboplatin and etoposide–based chemotherapy induced fast tumor shrinkage, avoiding CSF diversion (n = 5) and resolving hydrocephalus with a transient EVD (n = 5). The median duration until EVD removal was 7 days (range 2–10 days). Two of 12 patients with EVD ultimately required a VP shunt. Kaplan-Meier overall survival was 100% and progression-free survival was 96.4% at a median follow-up of 10.4 years. CONCLUSIONS Timely initiation of chemotherapy is imperative to rapidly reduce tumor bulk in children with germinoma and limits the need for VP shunt insertions. In children in whom CSF diversion is required, hydrocephalus may be successfully managed with a temporary EVD ± ETV.

Cancers arising from germline DNA mismatch-repair or polymerase-proofreading deficiencies (MMRD and PPD) in children harbour the highest mutational and microsatellite insertion/deletion (MS-indel) burden in humans and are lethal due to inherent resistance to chemo-irradiation. Although immune checkpoint inhibitors (ICI) have failed to benefit children in previous studies, we hypothesized that hypermutation caused by MMRD and PPD will improve outcomes following ICI in these patients. ICI treatment of 45 progressive/recurrent tumours from 38 patients revealed durable objective responses in the majority, culminating in 3-year survival of 41.4%. High mutation burden predicted response for ultra-hypermutant cancers (>100 mutations/Mb) enriched for combined MMRD+PPD, while MS-indels predicted response in MMRD tumours with lower mutation burden (10-100 mutations/Mb). Further, both mechanisms were associated with increased immune infiltration even in “immunologically-cold” tumours such as gliomas, contributing to the favorable response. Pseudo-progression (flare) was common and associated with immune activation in both the tumour microenvironment and systemically. Further, patients with flare continuing ICI treatment achieved durable responses. Our study demonstrates improved survival for patients with tumours not previously known to respond to ICI, including CNS and synchronous cancers, and identifies the dual roles of mutation burden and MS-indels in predicting sustained responses to immunotherapy.

Despite lower failure and infection rates compared with shunt placement, it has not been known whether endoscopic third ventriculostomy/choroid plexus cauterization (ETV/CPC) might be inferior in regard to neurocognitive development. This study is the first to describe neurocognitive outcome and ventricle volume in infants with hydrocephalus due to myelomeningocele that was treated primarily by ETV/CPC.The modified Bayley Scales of Infant Development (BSID-III) test was administered to 93 children with spina bifida who were 5-52 months of age. Fifty-five of these children had been treated by ETV/CPC, 19 received ventriculoperitoneal (VP) shunts, and 19 had required no treatment for hydrocephalus. Raw scores were converted to scaled scores for comparison with age-corrected norms. Ventricular volume was assessed by frontal/occipital horn ratio (FOR) calculated from late postoperative CT scans. The mean values between and among groups of patients were compared using independent samples t-test and ANOVA. The comparison of mean values to population normal means was performed using the single-sample t-test. Linear regression analyses were performed using BSID scores as the dependent variables, with treatment group and ventricular size (FOR) as the independent variables. Probability values0.05 were considered significant.There was no significant difference in mean age at assessment among groups (p = 0.8). The mean scale scores for untreated patients were no different from normal (all p0.27) in all portions of the BSID (excluding gross motor), and were generally significantly better than those for both VP shunt-treated and ETV/CPC groups. The ETV/ CPC-treated patients had nonsignificantly better mean scores than patients treated with VP shunts in all portions of the BSID (all p0.06), except receptive communication, which was significantly better for the ETV/CPC group (p = 0.02). The mean FOR was similar among groups, with no significant difference between the untreated group and either the VP shunt or ETV/CPC groups. The FOR did not correlate with performance.The ETV/CPC and VP shunt groups had similar neurocognitive outcomes. Neurocognitive outcomes for infants not requiring treatment for hydrocephalus were normal and significantly better than in those requiring treatment. The mean ventricular volume was similar among all 3 groups, and significantly larger than normal. There was no association between FOR and performance. Stable mild-to-moderate ventriculomegaly alone should not trigger intervention in asymptomatic infants with spina bifida.