The Bacterial and Viral Complexity of Postinfectious Hydrocephalus in Uganda

Abstract

Postinfectious hydrocephalus (PIH), often following neonatal sepsis, is the most common cause of pediatric hydrocephalus world-wide, yet the microbial pathogens remain uncharacterized. Characterization of the microbial agents causing PIH would lead to an emphasis shift from surgical palliation of cerebrospinal fluid (CSF) accumulation to prevention. We examined blood and CSF from 100 consecutive cases of PIH and control cases of non-postinfectious hydrocephalus (NPIH) in infants in Uganda. Genomic testing was undertaken for bacterial, fungal, and parasitic DNA, DNA and RNA sequencing for viral identification, and extensive bacterial culture recovery. We uncovered a major contribution to PIH from Paenibacillus, upon a background of frequent cytomegalovirus (CMV) infection. CMV was only found in CSF in PIH cases. A facultatively anaerobic isolate was recovered. Assembly of the genome revealed a strain of P. thiaminolyticus. In mice, this isolate designated strain Mbale, was lethal in contrast with the benign reference strain. These findings point to the value of an unbiased pan-microbial approach to characterize PIH in settings where the organisms remain unknown, and enables a pathway towards more optimal treatment and prevention of the proximate neonatal infections.

Central nervous system immune response in postinfectious hydrocephalus

“…Previous 16S rRNA sequencing had recovered Paenibacillus spp . from 59% of the PIH infants in this study, of which 8 and 27 patients also had Human Herpesvirus 5 (cytomegalovirus, CMV) in the CSF or blood 16 , respectively. These previous findings directed stratification of our patients into “Paeni-positive” or “Paeni-negative,” “CMV-CSF-positive” or “CMV-CSF-negative,” and “CMV-serum-positive” or “CMV-serum-negative.” Comparison of demographic and clinical attributes between Paeni-positive and Paeni-negative patients showed that Paeni-positive patients had higher white blood cell (WBC) counts in peripheral blood (11.9 vs 9.3 × 10 3 /µL, p=0.002) and CSF (71.6 vs 5.0 × 10 3 /µL, p<.001), and lower blood hemoglobin levels (10.8g/dL vs 12.0 g/dL, p=0.039) than those of Paeni-negative patients.…”

“…Identifying CMV in the CSF of a subset of infants in our cohort 16 raises the important question of whether the host-immune response we observed was, at least in part, attributable to CMV. While there were differentially expressed transcripts detected in CSF and/or serum consistent with the host response to central nervous system viral infection in CMV-positive infants, we did not detect any functional proteins associated with a response to CMV, nor was there any effect of CMV status on the differential expression of host-immune markers at the protein level.…”

“…A recent pan-microbial approach uncovered Paenibacillus spp . as a novel PIH pathogen associated with severe ventriculitis in a cohort of Ugandan children 16 . We hypothesize that the PIH host response is mediated by the activation of specific gene pathways, and that uncovering these pathways may identify therapeutic targets in hydrocephalus prevention.…”

“…To test this hypothesis, we performed high throughput proteomics and RNA sequencing (RNA-Seq) of cerebrospinal fluid (CSF) from 64 PIH infants and 36 non-postinfectious hydrocephalus (NPIH) infants to examine the immunopathogenesis of PIH 16-18 . Integrating deep-scale proteomics (i.e., high gene coverage) with genomic and/or transcriptomic data, known as proteogenomic analysis 19,20 , permits the exploration of gene networks and pathways underlying disease.…”

Vaginal Microbiome Topic Modelling of Laboring Ugandan Women With and Without Fever

“…For the V3-4 region, the annealing probe was the 341F primer combined with M13 (341F_M13) and the extended product was amplified with the 805R primer and M13. Amplification was done as previously described with 500 nM primers with the MolTaq 16S Mastermix (Molzym GmbH & Co Kg, Germany) 48 . For library preparation, after the amplified products were put into a 1x AMpure XP (Beckman Coulter) clean up, the Hyper Prep Kit (KAPA Biosystems, USA) library preparation kit was used following the manufacturer's protocols with 7 cycles of library amplification.…”