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Sullivan BA, Beam K, Vesoulis ZA, Aziz KB, Husain AN, Knake LA, Moreira AG, Hooven TA, Weiss EM, Carr NR, El-Ferzli GT, Patel RM, Simek KA, Hernandez AJ, Barry JS, McAdams RM. Transforming neonatal care with artificial intelligence: challenges, ethical consideration, and opportunities. J Perinatol 2024; 44:1-11. [PMID: 38097685 PMCID: PMC10872325 DOI: 10.1038/s41372-023-01848-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 11/21/2023] [Accepted: 11/30/2023] [Indexed: 12/17/2023]
Abstract
Artificial intelligence (AI) offers tremendous potential to transform neonatology through improved diagnostics, personalized treatments, and earlier prevention of complications. However, there are many challenges to address before AI is ready for clinical practice. This review defines key AI concepts and discusses ethical considerations and implicit biases associated with AI. Next we will review literature examples of AI already being explored in neonatology research and we will suggest future potentials for AI work. Examples discussed in this article include predicting outcomes such as sepsis, optimizing oxygen therapy, and image analysis to detect brain injury and retinopathy of prematurity. Realizing AI's potential necessitates collaboration between diverse stakeholders across the entire process of incorporating AI tools in the NICU to address testability, usability, bias, and transparency. With multi-center and multi-disciplinary collaboration, AI holds tremendous potential to transform the future of neonatology.
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Affiliation(s)
- Brynne A Sullivan
- Division of Neonatology, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Kristyn Beam
- Department of Neonatology, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Zachary A Vesoulis
- Division of Newborn Medicine, Department of Pediatrics, Washington University in St. Louis, St. Louis, MO, USA
| | - Khyzer B Aziz
- Division of Neonatology, Department of Pediatrics, Johns Hopkins University, Baltimore, MD, USA
| | - Ameena N Husain
- Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Lindsey A Knake
- Division of Neonatology, Department of Pediatrics, University of Iowa, Iowa City, IA, USA
| | - Alvaro G Moreira
- Division of Neonatology, Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Thomas A Hooven
- Division of Newborn Medicine, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Elliott M Weiss
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, USA
- Treuman Katz Center for Pediatric Bioethics and Palliative Care, Seattle Children's Research Institute, Seattle, WA, USA
| | - Nicholas R Carr
- Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - George T El-Ferzli
- Division of Neonatology, Department of Pediatrics, Ohio State University, Nationwide Children's Hospital, Columbus, OH, USA
| | - Ravi M Patel
- Division of Neonatology, Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, Atlanta, GA, USA
| | - Kelsey A Simek
- Division of Neonatology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Antonio J Hernandez
- Division of Neonatology, Department of Pediatrics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - James S Barry
- Division of Neonatology, Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, USA
| | - Ryan M McAdams
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
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2
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Liang CS, Sebastian A, McKennan C, Bertoni CB, Hooven TA, Kish M, Schwabenbauer K, Yanowitz T, King BC. Clinical and economic impacts of a modified-observational screening approach to well-appearing infants born to mothers with chorioamnionitis. J Perinatol 2023:10.1038/s41372-023-01858-3. [PMID: 38155229 DOI: 10.1038/s41372-023-01858-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 11/14/2023] [Accepted: 12/12/2023] [Indexed: 12/30/2023]
Abstract
OBJECTIVE Term infants born to mothers with chorioamnionitis are at risk for early-onset sepsis (EOS). We aimed to measure the impact of changing from a categorical to a modified-observational EOS screening approach on NICU admission, antibiotic utilization, and hospitalization costs. STUDY DESIGN Single-center retrospective pre-post cohort study of full-term infants born to mothers with chorioamnionitis. Primary outcomes included NICU admission, antibiotic utilization, and hospitalization costs. Outcomes were adjusted for demographic variables. Budget-impact analysis was performed using bootstrapping with replication. RESULTS 380 term infants were included (197 categorical; 183 modified-observational). There was a significant decrease in NICU admission and antibiotic utilization (p < 0.05) in the modified-observational cohort but no significant difference in per-patient total hospitalization costs. Budget-impact analysis suggested a high probability of cost savings. CONCLUSION A modified-observational approach to evaluating term infants of mothers with chorioamnionitis can reduce NICU admission and unnecessary antibiotic therapy, and may lead to cost-savings.
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Affiliation(s)
- Cynthia S Liang
- University of Pittsburgh, School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA.
- University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, USA.
- UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.
- UPMC Magee-Womens Hospital, Pittsburgh, PA, USA.
| | - Armand Sebastian
- University of Pittsburgh, School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA
- University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, USA
- UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA
- UPMC Magee-Womens Hospital, Pittsburgh, PA, USA
| | - Christopher McKennan
- University of Pittsburgh, School of Arts and Sciences, Department of Statistics, Pittsburgh, PA, USA
| | - C Briana Bertoni
- University of Pittsburgh, School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA
- University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, USA
- UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA
- UPMC Magee-Womens Hospital, Pittsburgh, PA, USA
| | - Thomas A Hooven
- University of Pittsburgh, School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA
- University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, USA
- UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA
- UPMC Magee-Womens Hospital, Pittsburgh, PA, USA
- UPMC Children's Hospital of Pittsburgh Richard King Mellon Institute for Pediatric Research, Pittsburgh, PA, USA
| | - Mary Kish
- University of Pittsburgh, School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA
- University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, USA
- UPMC Magee-Womens Hospital, Pittsburgh, PA, USA
| | - Kathleen Schwabenbauer
- University of Pittsburgh, School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA
- University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, USA
- UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA
- UPMC Magee-Womens Hospital, Pittsburgh, PA, USA
| | - Toby Yanowitz
- University of Pittsburgh, School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA
- University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, USA
- UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA
- UPMC Magee-Womens Hospital, Pittsburgh, PA, USA
| | - Brian C King
- University of Pittsburgh, School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA
- University of Pittsburgh Medical Center (UPMC), Pittsburgh, PA, USA
- UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA
- UPMC Magee-Womens Hospital, Pittsburgh, PA, USA
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3
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Bhavana VH, Hillebrand GH, Gopalakrishna KP, Rapp RA, Ratner AJ, Tettelin H, Hooven TA. A group B Streptococcus indexed transposon mutant library to accelerate genetic research on an important perinatal pathogen. Microbiol Spectr 2023; 11:e0204623. [PMID: 37933989 PMCID: PMC10714824 DOI: 10.1128/spectrum.02046-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 09/29/2023] [Indexed: 11/08/2023] Open
Abstract
IMPORTANCE Group B Streptococcus (GBS) is a significant global cause of serious infections, most of which affect pregnant women, newborns, and infants. Studying GBS genetic mutant strains is a valuable approach for learning more about how these infections are caused and is a key step toward developing more effective preventative and treatment strategies. In this resource report, we describe a newly created library of defined GBS genetic mutants, containing over 1,900 genetic variants, each with a unique disruption to its chromosome. An indexed library of this scale is unprecedented in the GBS field; it includes strains with mutations in hundreds of genes whose potential functions in human disease remain unknown. We have made this resource freely available to the broader research community through deposition in a publicly funded bacterial maintenance and distribution repository.
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Affiliation(s)
- Venkata H. Bhavana
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Gideon H. Hillebrand
- University of Pittsburgh, Graduate Program in Microbiology and Immunology, Pittsburgh, Pennsylvania, USA
| | | | - Rebekah A. Rapp
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- The Ellis School, Pittsburgh, Pennsylvania, USA
| | - Adam J. Ratner
- Department of Pediatrics, New York University, New York, New York, USA
- Department of Microbiology, New York University, New York, New York, USA
| | - Hervé Tettelin
- Department of Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Thomas A. Hooven
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
- University of Pittsburgh, Graduate Program in Microbiology and Immunology, Pittsburgh, Pennsylvania, USA
- Richard King Mellon Institute for Pediatric Research, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania, USA
- UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Gopalakrishna KP, Hillebrand GH, Bhavana VH, Elder JL, D'Mello A, Tettelin H, Hooven TA. Group B Streptococcus Cas9 variants provide insight into programmable gene repression and CRISPR-Cas transcriptional effects. Commun Biol 2023; 6:620. [PMID: 37296208 PMCID: PMC10256743 DOI: 10.1038/s42003-023-04994-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023] Open
Abstract
Group B Streptococcus (GBS; S. agalactiae) causes chorioamnionitis, neonatal sepsis, and can also cause disease in healthy or immunocompromised adults. GBS possesses a type II-A CRISPR-Cas9 system, which defends against foreign DNA within the bacterial cell. Several recent publications have shown that GBS Cas9 influences genome-wide transcription through a mechanism uncoupled from its function as a specific, RNA-programmable endonuclease. We examine GBS Cas9 effects on genome-wide transcription through generation of several isogenic variants with specific functional defects. We compare whole-genome RNA-seq from Δcas9 GBS with a full-length Cas9 gene deletion; dcas9 defective in its ability to cleave DNA but still able to bind to frequently occurring protospacer adjacent motifs; and scas9 that retains its catalytic domains but is unable to bind protospacer adjacent motifs. Comparing scas9 GBS to the other variants, we identify nonspecific protospacer adjacent motif binding as a driver of genome-wide, Cas9 transcriptional effects in GBS. We also show that Cas9 transcriptional effects from nonspecific scanning tend to influence genes involved in bacterial defense and nucleotide or carbohydrate transport and metabolism. While genome-wide transcription effects are detectable by analysis of next-generation sequencing, they do not result in virulence changes in a mouse model of sepsis. We also demonstrate that catalytically inactive dCas9 expressed from the GBS chromosome can be used with a straightforward, plasmid-based, single guide RNA expression system to suppress transcription of specific GBS genes without potentially confounding off-target effects. We anticipate that this system will be useful for study of nonessential and essential gene roles in GBS physiology and pathogenesis.
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Affiliation(s)
| | - Gideon H Hillebrand
- University of Pittsburgh School of Medicine, Program in Microbiology and Immunology, Pittsburgh, PA, USA
| | - Venkata H Bhavana
- University of Pittsburgh School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA
| | - Jordan L Elder
- The Cleveland Clinic, Clinical Laboratory Services, Cleveland, OH, USA
| | - Adonis D'Mello
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Hervé Tettelin
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Thomas A Hooven
- University of Pittsburgh School of Medicine, Department of Pediatrics, Pittsburgh, PA, USA.
- Richard King Mellon Institute for Pediatric Research, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
- UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.
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Gopalakrishna KP, Hillebrand GH, Bhavana VH, Elder JL, D'Mello A, Tettelin H, Hooven TA. Group B Streptococcus Cas9 variants provide insight into programmable gene repression and CRISPR-Cas transcriptional effects. bioRxiv 2023:2023.05.24.542094. [PMID: 37292749 PMCID: PMC10245859 DOI: 10.1101/2023.05.24.542094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Group B Streptococcus (GBS; S. agalactiae ) causes chorioamnionitis, neonatal sepsis, and can also cause disease in healthy or immunocompromised adults. GBS possesses a type II-A CRISPR-Cas9 system, which defends against foreign DNA within the bacterial cell. Several recent publications have shown that GBS Cas9 influences genome-wide transcription through a mechanism uncoupled from its function as a specific, RNA-programmable endonuclease. We examine GBS Cas9 effects on genome-wide transcription through generation of several isogenic variants with specific functional defects. We compare whole-genome RNA-seq from Δ cas9 GBS with a full-length Cas9 gene deletion; dcas9 defective in its ability to cleave DNA but still able to bind to frequently occurring protospacer adjacent motifs; and scas9 that retains its catalytic domains but is unable to bind protospacer adjacent motifs. Comparing scas9 GBS to the other variants, we identify nonspecific protospacer adjacent motif binding as a driver of genome-wide, Cas9 transcriptional effects in GBS. We also show that Cas9 transcriptional effects from nonspecific scanning tend to influence genes involved in bacterial defense and nucleotide or carbohydrate transport and metabolism. While genome-wide transcription effects are detectable by analysis of next-generation sequencing, they do not result in virulence changes in a mouse model of sepsis. We also demonstrate that catalytically inactive dCas9 expressed from the GBS chromosome can be used with a straightforward, plasmid-based, single guide RNA expression system to suppress transcription of specific GBS genes without potentially confounding off-target effects. We anticipate that this system will be useful for study of nonessential and essential gene roles in GBS physiology and pathogenesis.
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6
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Abstract
See Bonus NeoBriefs videos and downloadable teaching slides Intubated infants in the NICU are at risk of developing ventilator-associated pneumonia (VAP), a common type of health care-associated infection. The Centers for Disease Control and Prevention developed guidelines for diagnosing VAP in patients younger than 1 year, which include worsening gas exchange, radiographic findings, and at least 3 defined clinical signs of pneumonia. VAP in infants is treated with empiric antibiotics selected based on local resistance patterns and individualized patient data. Many NICUs have implemented prevention bundles in an effort to decrease VAP by ensuring the cleanest environment for intubated neonates (hand hygiene, sterile handling of equipment), positioning of infants to prevent gastric reflux, and constantly reevaluating for extubation readiness. Although these prevention bundle elements are intuitive and generally low risk, none are based on strong research support. This article reviews the epidemiology, pathogenesis, diagnosis, treatment, and prevention of VAP in NICU patients, focusing on recent evidence, highlighting areas of emerging research, and identifying persistent knowledge gaps.
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Affiliation(s)
- Ayesha Alriyami
- Division of Newborn Medicine, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA
| | - James R Kiger
- Division of Newborn Medicine, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA.,Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Thomas A Hooven
- Division of Newborn Medicine, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA.,Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA.,Richard King Mellon Institute for Pediatric Research, Pittsburgh, PA
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Lin YC, Salleb-Aouissi A, Hooven TA. Interpretable prediction of necrotizing enterocolitis from machine learning analysis of premature infant stool microbiota. BMC Bioinformatics 2022; 23:104. [PMID: 35337258 PMCID: PMC8953333 DOI: 10.1186/s12859-022-04618-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 02/23/2022] [Indexed: 12/18/2022] Open
Abstract
Background Necrotizing enterocolitis (NEC) is a common, potentially catastrophic intestinal disease among very low birthweight premature infants. Affecting up to 15% of neonates born weighing less than 1500 g, NEC causes sudden-onset, progressive intestinal inflammation and necrosis, which can lead to significant bowel loss, multi-organ injury, or death. No unifying cause of NEC has been identified, nor is there any reliable biomarker that indicates an individual patient’s risk of the disease. Without a way to predict NEC in advance, the current medical strategy involves close clinical monitoring in an effort to treat babies with NEC as quickly as possible before irrecoverable intestinal damage occurs. In this report, we describe a novel machine learning application for generating dynamic, individualized NEC risk scores based on intestinal microbiota data, which can be determined from sequencing bacterial DNA from otherwise discarded infant stool. A central insight that differentiates our work from past efforts was the recognition that disease prediction from stool microbiota represents a specific subtype of machine learning problem known as multiple instance learning (MIL). Results We used a neural network-based MIL architecture, which we tested on independent datasets from two cohorts encompassing 3595 stool samples from 261 at-risk infants. Our report also introduces a new concept called the “growing bag” analysis, which applies MIL over time, allowing incorporation of past data into each new risk calculation. This approach allowed early, accurate NEC prediction, with a mean sensitivity of 86% and specificity of 90%. True-positive NEC predictions occurred an average of 8 days before disease onset. We also demonstrate that an attention-gated mechanism incorporated into our MIL algorithm permits interpretation of NEC risk, identifying several bacterial taxa that past work has associated with NEC, and potentially pointing the way toward new hypotheses about NEC pathogenesis. Our system is flexible, accepting microbiota data generated from targeted 16S or “shotgun” whole-genome DNA sequencing. It performs well in the setting of common, potentially confounding preterm neonatal clinical events such as perinatal cardiopulmonary depression, antibiotic administration, feeding disruptions, or transitions between breast feeding and formula. Conclusions We have developed and validated a robust MIL-based system for NEC prediction from harmlessly collected premature infant stool. While this system was developed for NEC prediction, our MIL approach may also be applicable to other diseases characterized by changes in the human microbiota. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-022-04618-w.
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Affiliation(s)
- Yun Chao Lin
- Department of Computer Science, Columbia University, 1214 Amsterdam Ave., Mailcode 0401, New York, 10027, USA
| | - Ansaf Salleb-Aouissi
- Department of Computer Science, Columbia University, 1214 Amsterdam Ave., Mailcode 0401, New York, 10027, USA.
| | - Thomas A Hooven
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, USA.,Richard King Mellon Institute for Pediatric Research, UPMC Children's Hospital of Pittsburgh, Pittsburgh, USA
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Dammann AN, Chamby AB, Gonzalez FJ, Sharp ME, Flores K, Shahi I, Dongas S, Hooven TA, Ratner AJ. Group B Streptococcus capsular serotype alters vaginal colonization fitness. J Infect Dis 2021; 225:1896-1904. [PMID: 34788438 DOI: 10.1093/infdis/jiab559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 11/02/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Group B Streptococcus (GBS) remains a leading cause of infant morbidity and mortality. A candidate vaccine targets six GBS serotypes, offering a potential alternative to intrapartum antibiotic prophylaxis to reduce disease burden. However, our understanding of the contributions of specific capsule types to GBS colonization and disease remains limited. METHODS Using allelic exchange, we generated isogenic GBS strains differing only in the serotype-determining region in two genetic backgrounds, including the hypervirulent clonal complex (CC) 17. Using a murine model of vaginal co-colonization, we evaluated the roles of the presence of capsule and of expression of specific capsular types in GBS vaginal colonization fitness independent of other genetic factors. RESULTS Encapsulated wild-type strains COH1 (CC17, serotype III) and A909 (non-CC17, serotype Ia), outcompeted isogenic acapsular mutants in murine vaginal co-colonization. COH1 wild-type outcompeted A909. Notably, expression of type Ia capsule conferred an advantage over type III capsule in both genetic backgrounds. CONCLUSIONS Specific capsule types may provide an advantage in GBS vaginal colonization in vivo. However, success of certain GBS lineages, including CC17, likely involves both capsule and non-capsule genetic elements. Capsule switching in GBS, a potential outcome of conjugate vaccine programs, may alter colonization fitness or pathogenesis.
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Affiliation(s)
- Allison N Dammann
- Department of Pediatrics, New York University Grossman School of Medicine, New York, NY, USA
| | - Anna B Chamby
- Department of Pediatrics, New York University Grossman School of Medicine, New York, NY, USA
| | - Francisco J Gonzalez
- Department of Pediatrics, New York University Grossman School of Medicine, New York, NY, USA
| | - Molly E Sharp
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY, USA
| | - Karina Flores
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY, USA
| | - Ifrah Shahi
- Department of Microbiology, New York University Grossman School of Medicine, New York, NY, USA
| | - Sophia Dongas
- Department of Pediatrics, New York University Grossman School of Medicine, New York, NY, USA
| | - Thomas A Hooven
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,Richard King Mellon Institute for Pediatric Research, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA
| | - Adam J Ratner
- Department of Pediatrics, New York University Grossman School of Medicine, New York, NY, USA.,Department of Microbiology, New York University Grossman School of Medicine, New York, NY, USA
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Abstract
Antibiotics are extensively and inconsistently prescribed in neonatal ICUs, and usage does not correlate with rates of culture positive sepsis. There is mounting data describing the short and long-term adverse effects associated with antibiotic overuse in neonates, including the increased burden of multi-drug resistant organisms. Currently there is considerable variation in antibiotic prescribing practice among neonatologists. Applying the practice of antibiotic stewardship in the NICU is crucial for standardizing antibiotic use and improving outcomes in this population. Several approaches have been proposed to identify neonatal sepsis, with the hope of reducing antibiotic utilization. These strategies all have their limitations, and often include laboratory testing and treatment of well-appearing, non-septic, infants. A conservative "watch and wait" algorithm is suggested as an alternative method for when to initiate antibiotics. This observational approach relies on availability of trained personnel able to examine infants at specified intervals, without delaying antibiotics, should signs of sepsis arise.
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Affiliation(s)
- Noa Fleiss
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT, USA
| | - Thomas A Hooven
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Richard A Polin
- Department of Pediatrics, Columbia University School of Medicine, New York City, NY, USA.
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10
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Dammann AN, Chamby AB, Catomeris AJ, Davidson KM, Tettelin H, van Pijkeren JP, Gopalakrishna KP, Keith MF, Elder JL, Ratner AJ, Hooven TA. Genome-Wide fitness analysis of group B Streptococcus in human amniotic fluid reveals a transcription factor that controls multiple virulence traits. PLoS Pathog 2021; 17:e1009116. [PMID: 33684178 PMCID: PMC7971860 DOI: 10.1371/journal.ppat.1009116] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 03/18/2021] [Accepted: 02/18/2021] [Indexed: 02/06/2023] Open
Abstract
Streptococcus agalactiae (group B Streptococcus; GBS) remains a dominant cause of serious neonatal infections. One aspect of GBS that renders it particularly virulent during the perinatal period is its ability to invade the chorioamniotic membranes and persist in amniotic fluid, which is nutritionally deplete and rich in fetal immunologic factors such as antimicrobial peptides. We used next-generation sequencing of transposon-genome junctions (Tn-seq) to identify five GBS genes that promote survival in the presence of human amniotic fluid. We confirmed our Tn-seq findings using a novel CRISPR inhibition (CRISPRi) gene expression knockdown system. This analysis showed that one gene, which encodes a GntR-class transcription factor that we named MrvR, conferred a significant fitness benefit to GBS in amniotic fluid. We generated an isogenic targeted deletion of the mrvR gene, which had a growth defect in amniotic fluid relative to the wild type parent strain. The mrvR deletion strain also showed a significant biofilm defect in vitro. Subsequent in vivo studies showed that while the mutant was able to cause persistent murine vaginal colonization, pregnant mice colonized with the mrvR deletion strain did not develop preterm labor despite consistent GBS invasion of the uterus and the fetoplacental units. In contrast, pregnant mice colonized with wild type GBS consistently deliver prematurely. In a sepsis model the mrvR deletion strain showed significantly decreased lethality. In order to better understand the mechanism by which this newly identified transcription factor controls GBS virulence, we performed RNA-seq on wild type and mrvR deletion GBS strains, which revealed that the transcription factor affects expression of a wide range of genes across the GBS chromosome. Nucleotide biosynthesis and salvage pathways were highly represented among the set of differentially expressed genes, suggesting that MrvR may be involved in regulating nucleotide availability. Group B Streptococcus (GBS) is a species of Gram-positive bacteria that often colonizes the healthy adult intestinal and reproductive tracts without causing serious symptoms. During pregnancy, however, GBS can invade the pregnant uterus, where it can cause infection of the placenta, fetal membranes, and fetus—a condition known as chorioamnionitis. Chorioamnionitis is associated with serious adverse pregnancy outcomes, including stillbirth, preterm labor, and severe infection of the newborn. GBS can survive in human amniotic fluid, which is low in bacterial nutrients and contains immune molecules that limit microbial persistence, and this ability likely contributes to GBS chorioamnionitis. This study is focused on a single GBS gene that encodes a genetic regulator we called MrvR, which we show is important for GBS resistance to human amniotic fluid. Using a series of genetic techniques combined with animal models of GBS colonization and infection, we show that MrvR also plays a key role in allowing GBS to invade the bloodstream and trigger the inflammatory responses that lead to preterm labor and stillbirth. The study concludes with a survey of other GBS genes whose activity is regulated by MrvR, which seems to be an important contributor to GBS virulence.
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Affiliation(s)
- Allison N. Dammann
- Department of Pediatrics, New York University School of Medicine, New York, New York, United States of America
| | - Anna B. Chamby
- University of Vermont Larner College of Medicine, Burlington, Vermont, United States of America
| | - Andrew J. Catomeris
- Georgetown University School of Medicine, Washington, District of Columbia, United States of America
| | - Kyle M. Davidson
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Hervé Tettelin
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Jan-Peter van Pijkeren
- Department of Food Science, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Kathyayini P. Gopalakrishna
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Mary F. Keith
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Jordan L. Elder
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Adam J. Ratner
- Department of Pediatrics, New York University School of Medicine, New York, New York, United States of America
- Department of Microbiology, New York University, New York, New York, United States of America
| | - Thomas A. Hooven
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Richard King Mellon Institute for Pediatric Research, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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11
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Affiliation(s)
- Faith Kim
- Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons, NY, USA
| | - Richard A Polin
- Department of Pediatrics, Columbia University Vagelos College of Physicians and Surgeons, NY, USA
| | - Thomas A Hooven
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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12
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Kim F, Reichman V, Hooven TA. Human Herpesvirus-6 Meningitis in a Premature Infant with Fevers: A Case and Literature Review. Clin Med Insights Case Rep 2020; 13:1179547620912952. [PMID: 32341669 PMCID: PMC7169356 DOI: 10.1177/1179547620912952] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/20/2020] [Indexed: 01/27/2023]
Abstract
Human herpesvirus-6 (HHV-6) is a common virus that can cause nearly universal infection in infancy and early childhood. It typically manifests as an acute febrile illness. We describe a case of a premature infant with congenital hydrocephalus secondary to aqueductal stenosis with a ventriculoperitoneal shunt in place who developed intermittent fevers while she was admitted to the neonatal intensive care unit. She was ultimately diagnosed with acute HHV-6 meningitis. In addition to this report, we present a literature review regarding this virus’s potential modes of transmission and forms of clinical presentation in the neonatal period.
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Affiliation(s)
- Faith Kim
- Division of Neonatology, Department of Pediatrics, Columbia University Irving Medical Center, NewYork-Presbyterian Morgan Stanley Children’s Hospital, New York, NY, USA
| | - Victoria Reichman
- Division of Neonatology, Department of Pediatrics, Columbia University Irving Medical Center, NewYork-Presbyterian Morgan Stanley Children’s Hospital, New York, NY, USA
| | - Thomas A Hooven
- Division of Neonatology/Newborn Medicine, UPMC Children’s Hospital of Pittsburgh, Pittsburgh, PA, USA
- Thomas A Hooven, Division of Neonatology/Newborn Medicine, UPMC Children’s Hospital of Pittsburgh, 4401 Penn Ave, Rangos Research Building #8128, Pittsburgh, PA 15224, USA.
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Hooven TA, Lin AYC, Salleb-Aouissi A. Multiple Instance Learning for Predicting Necrotizing Enterocolitis in Premature Infants Using Microbiome Data. Proc ACM Conf Health Inference Learn (2020) 2020; 2020:99-109. [PMID: 34318306 PMCID: PMC8313028 DOI: 10.1145/3368555.3384466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Necrotizing enterocolitis (NEC) is a life-threatening intestinal disease that primarily affects preterm infants during their first weeks after birth. Mortality rates associated with NEC are 15-30%, and surviving infants are susceptible to multiple serious, long-term complications. The disease is sporadic and, with currently available tools, unpredictable. We are creating an early warning system that uses stool microbiome features, combined with clinical and demographic information, to identify infants at high risk of developing NEC. Our approach uses a multiple instance learning, neural network-based system that could be used to generate daily or weekly NEC predictions for premature infants. The approach was selected to effectively utilize sparse and weakly annotated datasets characteristic of stool microbiome analysis. Here we describe initial validation of our system, using clinical and microbiome data from a nested case-control study of 161 preterm infants. We show receiver-operator curve areas above 0.9, with 75% of dominant predictive samples for NEC-affected infants identified at least 24 hours prior to disease onset. Our results pave the way for development of a real-time early warning system for NEC using a limited set of basic clinical and demographic details combined with stool microbiome data.
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Abstract
Early-onset sepsis (EOS) is an important cause of neonatal morbidity. Despite extensive study, identifying at-risk newborns remains challenging, especially if they are initially well appearing. Existing official EOS recommendations suggest a conservative approach that likely results in overtreatment of a low-risk population. Recent studies indicate that more precise risk assessment and alternative management strategies could decrease the number of infants exposed to blood draws and antibiotics during evaluations for EOS. This article reviews existing guidelines and provides an overview of the Bayesian sepsis calculator and serial observation as an alternative to laboratory studies and empirical antibiotics.
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Affiliation(s)
- Pamela I Good
- Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University, 630 West 168th Street, PH-17, New York, NY 10032, USA
| | - Thomas A Hooven
- Department of Pediatrics, Vagelos College of Physicians and Surgeons, Columbia University, 630 West 168th Street, PH-17, New York, NY 10032, USA.
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15
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Khatami A, Randis TM, Chamby A, Hooven TA, Gegick M, Suzman E, A’Hearn-Thomas B, Steenhoff AP, Ratner AJ. Improving the Sensitivity of Real-time PCR Detection of Group B Streptococcus Using Consensus Sequence-Derived Oligonucleotides. Open Forum Infect Dis 2018; 5:ofy164. [PMID: 30038931 PMCID: PMC6051451 DOI: 10.1093/ofid/ofy164] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 07/03/2018] [Indexed: 12/20/2022] Open
Abstract
Group B Streptococcus (GBS) is a perinatal pathogen and an emerging cause of disease in adults. Culture-independent GBS detection relies on polymerase chain reaction (PCR) of conserved genes, including sip. We demonstrate suboptimal sensitivity of the existing sip PCR strategy and validate an improved method based on consensus sequences from >100 GBS genomes.
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Affiliation(s)
- Ameneh Khatami
- Departments of Pediatrics and Microbiology, New York University School of Medicine, New York, New York
| | - Tara M Randis
- Departments of Pediatrics and Microbiology, New York University School of Medicine, New York, New York
| | - Anna Chamby
- Departments of Pediatrics and Microbiology, New York University School of Medicine, New York, New York
| | - Thomas A Hooven
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, New York
| | - Margaret Gegick
- Departments of Pediatrics and Microbiology, New York University School of Medicine, New York, New York
| | - Evan Suzman
- Departments of Pediatrics and Microbiology, New York University School of Medicine, New York, New York
| | - Brady A’Hearn-Thomas
- Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Andrew P Steenhoff
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
- Division of Pediatric Infectious Diseases, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Adam J Ratner
- Departments of Pediatrics and Microbiology, New York University School of Medicine, New York, New York
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16
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Hooven TA. Does a procalcitonin-guided approach to term and late-preterm neonates with suspected early-onset sepsis safely decrease unnecessary antibiotic exposure? Acta Paediatr 2018; 107:359-360. [PMID: 29131403 DOI: 10.1111/apa.14121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Neonatal pneumonia may occur in isolation or as one component of a larger infectious process. Bacteria, viruses, fungi, and parasites are all potential causes of neonatal pneumonia, and may be transmitted vertically from the mother or acquired from the postnatal environment. The patient's age at the time of disease onset may help narrow the differential diagnosis, as different pathogens are associated with congenital, early-onset, and late-onset pneumonia. Supportive care and rationally selected antimicrobial therapy are the mainstays of treatment for neonatal pneumonia. The challenges involved in microbiological testing of the lower airways may prevent definitive identification of a causative organism. In this case, secondary data must guide selection of empiric therapy, and the response to treatment must be closely monitored.
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Affiliation(s)
| | - Richard A. Polin
- Corresponding author. Babies Hospital Central, 115, New York, NY, USA.
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18
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Affiliation(s)
- Thomas A Hooven
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Richard A Polin
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York
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19
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Hooven TA, Catomeris AJ, Akabas LH, Randis TM, Maskell DJ, Peters SE, Ott S, Santana-Cruz I, Tallon LJ, Tettelin H, Ratner AJ. The essential genome of Streptococcus agalactiae. BMC Genomics 2016; 17:406. [PMID: 27229469 PMCID: PMC4881062 DOI: 10.1186/s12864-016-2741-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/14/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Next-generation sequencing of transposon-genome junctions from a saturated bacterial mutant library (Tn-seq) is a powerful tool that permits genome-wide determination of the contribution of genes to fitness of the organism under a wide range of experimental conditions. We report development, testing, and results from a Tn-seq system for use in Streptococcus agalactiae (group B Streptococcus; GBS), an important cause of neonatal sepsis. METHODS Our method uses a Himar1 mini-transposon that inserts at genomic TA dinucleotide sites, delivered to GBS on a temperature-sensitive plasmid that is subsequently cured from the bacterial population. In order to establish the GBS essential genome, we performed Tn-seq on DNA collected from three independent mutant libraries-with at least 135,000 mutants per library-at serial 24 h time points after outgrowth in rich media. RESULTS After statistical analysis of transposon insertion density and distribution, we identified 13.5 % of genes as essential and 1.2 % as critical, with high levels of reproducibility. Essential and critical genes are enriched for fundamental cellular housekeeping functions, such as acyl-tRNA biosynthesis, nucleotide metabolism, and glycolysis. We further validated our system by comparing fitness assignments of homologous genes in GBS and a close bacterial relative, Streptococcus pyogenes, which demonstrated 93 % concordance. Finally, we used our fitness assignments to identify signal transduction pathway components predicted to be essential or critical in GBS. CONCLUSIONS We believe that our baseline fitness assignments will be a valuable tool for GBS researchers and that our system has the potential to reveal key pathogenesis gene networks and potential therapeutic/preventative targets.
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Affiliation(s)
- Thomas A Hooven
- Department of Pediatrics, Columbia University, New York, NY, USA
| | - Andrew J Catomeris
- Department of Pediatrics, Division of Pediatric Infectious Diseases, New York University School of Medicine, 550 First Avenue (MSB 223), New York, NY, 10016, USA
| | - Leor H Akabas
- Department of Pediatrics, Columbia University, New York, NY, USA
| | - Tara M Randis
- Department of Pediatrics, Division of Pediatric Infectious Diseases, New York University School of Medicine, 550 First Avenue (MSB 223), New York, NY, 10016, USA
| | - Duncan J Maskell
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Sarah E Peters
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Sandra Ott
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Ivette Santana-Cruz
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Luke J Tallon
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Hervé Tettelin
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Adam J Ratner
- Department of Pediatrics, Division of Pediatric Infectious Diseases, New York University School of Medicine, 550 First Avenue (MSB 223), New York, NY, 10016, USA. .,Department of Microbiology, New York University School of Medicine, New York, NY, USA.
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20
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Hooven TA, Hooper EM, Wontakal SN, Francis RO, Sahni R, Lee MT. Diagnosis of a rare fetal haemoglobinopathy in the age of next-generation sequencing. BMJ Case Rep 2016; 2016:10.1136/bcr-2016-215193. [PMID: 27095814 DOI: 10.1136/bcr-2016-215193] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Neonatal cyanosis resulting from a fetal methaemoglobin variant is rare. Most such variants are only described in a few published case reports. We present the case of a newborn with unexplained persistent cyanosis, ultimately determined to have a γ-chain mutation causing Hb FM-Fort Ripley. This neonatal haemoglobinopathy can be challenging to diagnose, as significant oxygen desaturation may result from barely detectable levels of the mutant haemoglobin and co-oximetry studies may show a falsely normal methaemoglobin level. Our analysis of the infant's haemoglobin included high-performance liquid chromatography, cellulose acetate electrophoresis and citrate agar electrophoresis, which showed trace amounts of a suspected variant. Ultimately, the diagnosis was made through a novel application of next-generation sequencing (NGS). NGS-based diagnostic approaches are becoming increasingly available to clinicians, and our case provides a framework and evidence for the utilisation of such testing paradigms in the diagnosis of a rare cause of neonatal cyanosis.
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Affiliation(s)
- Thomas A Hooven
- Department of Pediatrics, New York University Langone Medical Center, New York, New York, USA Department of Pediatrics, Columbia University, New York, New York, USA
| | - Ellen M Hooper
- Department of Pediatrics, Columbia University, New York, New York, USA
| | | | - Richard O Francis
- Department of Pathology, Columbia University, New York, New York, USA
| | - Rakesh Sahni
- Department of Pediatrics, Columbia University, New York, New York, USA
| | - Margaret T Lee
- Department of Pediatrics, Columbia University, New York, New York, USA
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21
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Abstract
Healthcare-associated infections in the neonatal intensive care unit add considerably to hospital stays and costs, and contribute to numerous adverse outcomes, including death. The relatively high prevalence of healthcare-associated infections among neonates is secondary to the newborn's underdeveloped immune system, the need for frequent invasive procedures, and generally prolonged hospitalization. Central line associated bloodstream infections (CLABSI) are the most common form of healthcare-associated infection, with coagulase-negative Staphylococcus species (CONS) being the most commonly cultured microorganism. Interpretation of culture results in the setting of any suspected healthcare-associated infection can be made difficult by the possibility that a recovered organism represents a commensal contaminant, rather than an actual cause of infection. This is especially true in the case of a blood culture that grows CONS during evaluation for suspected CLABSI. This article provides an overview of the epidemiology, diagnosis, prevention, and treatment of healthcare-associated infections in the NICU.
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Affiliation(s)
- Thomas A Hooven
- Division of Neonatology, Morgan Stanley Children's Hospital, Columbia University Medical Center, New York, USA
| | - Richard A Polin
- College of Physicians and Surgeons, Columbia University, New York, USA.
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22
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Randis TM, Gelber SE, Hooven TA, Abellar RG, Akabas LH, Lewis EL, Walker LB, Byland LM, Nizet V, Ratner AJ. Group B Streptococcus β-hemolysin/cytolysin breaches maternal-fetal barriers to cause preterm birth and intrauterine fetal demise in vivo. J Infect Dis 2014; 210:265-73. [PMID: 24474814 DOI: 10.1093/infdis/jiu067] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Maternal vaginal colonization with Streptococcus agalactiae (Group B Streptococcus [GBS]) is a precursor to chorioamnionitis, fetal infection, and neonatal sepsis, but the understanding of specific factors in the pathogenesis of ascending infection remains limited. METHODS We used a new murine model to evaluate the contribution of the pore-forming GBS β-hemolysin/cytolysin (βH/C) to vaginal colonization, ascension, and fetal infection. RESULTS Competition assays demonstrated a marked advantage to βH/C-expressing GBS during colonization. Intrauterine fetal demise and/or preterm birth were observed in 54% of pregnant mice colonized with wild-type (WT) GBS and 0% of those colonized with the toxin-deficient cylE knockout strain, despite efficient colonization and ascension by both strains. Robust placental inflammation, disruption of maternal-fetal barriers, and fetal infection were more frequent in animals colonized with WT bacteria. Histopathologic examination revealed bacterial tropism for fetal lung and liver. CONCLUSIONS Preterm birth and fetal demise are likely the direct result of toxin-induced damage and inflammation rather than differences in efficiency of ascension into the upper genital tract. These data demonstrate a distinct contribution of βH/C to GBS chorioamnionitis and subsequent fetal infection in vivo and showcase a model for this most proximal step in GBS pathogenesis.
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Affiliation(s)
- Tara M Randis
- Department of Pediatrics, Columbia University, New York, New York
| | - Shari E Gelber
- Department of Obstetrics and Gynecology, Weill-Cornell Medical Center, New York, New York
| | - Thomas A Hooven
- Department of Pediatrics, Columbia University, New York, New York
| | - Rosanna G Abellar
- Department of Pathology and Cell Biology, Columbia University, New York, New York
| | - Leor H Akabas
- Department of Pediatrics, Columbia University, New York, New York
| | - Emma L Lewis
- Department of Pediatrics, Columbia University, New York, New York
| | - Lindsay B Walker
- Department of Pediatrics, Columbia University, New York, New York
| | - Leah M Byland
- Department of Pediatrics, Columbia University, New York, New York
| | - Victor Nizet
- Department of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California
| | - Adam J Ratner
- Department of Pediatrics, Columbia University, New York, New York
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Hooven TA, Randis TM, Hymes SR, Rampersaud R, Ratner AJ. Retrocyclin inhibits Gardnerella vaginalis biofilm formation and toxin activity. J Antimicrob Chemother 2012; 67:2870-2. [PMID: 22855857 DOI: 10.1093/jac/dks305] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Retrocyclins are cyclic antimicrobial peptides that have been shown to be both broadly active and safe in animal models. RC-101, a synthetic retrocyclin, targets important human pathogens and is a candidate vaginal microbicide. Its activity against microbes associated with bacterial vaginosis is unknown. METHODS We investigated the effect of RC-101 on toxin activity, bacterial growth and biofilm formation of Gardnerella vaginalis in vitro. RESULTS RC-101 potently inhibits the cytolytic activity of vaginolysin, the Gardnerella vaginalis toxin, on both erythrocytes and nucleated cells. RC-101 lacks inhibitory activity against planktonic G. vaginalis but markedly decreases biofilm formation. CONCLUSIONS These dual properties, toxin inhibition and biofilm retardation, justify further exploration of RC-101 as a candidate agent for bacterial vaginosis prevention.
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Affiliation(s)
- Thomas A Hooven
- Department of Pediatrics, Division of Infectious Diseases, Columbia University, New York, NY 10032, USA
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Hooven TA, Yamamoto Y, Jeffery WR. Blind cavefish and heat shock protein chaperones: a novel role for hsp90alpha in lens apoptosis. Int J Dev Biol 2005; 48:731-8. [PMID: 15558465 DOI: 10.1387/ijdb.041874th] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Lens apoptosis plays a central role in cavefish eye degeneration. Heat shock proteins (hsps) can regulate apoptosis; therefore, we examined the relationship between constitutive hsp70 and hsp90 expression and lens apoptosis. The model system is Astyanax mexicanus, a teleost species consisting of an eyed surface-dwelling (surface fish) form and numerous blind cave-dwelling (cavefish) forms. Optic primordia are formed in the cavefish embryo but they subsequently undergo lens apoptosis, arrest in development and degenerate. Astyanax hsp90 and hsp70 DNAs were isolated to use as probes to compare gene expression during surface fish and cavefish development. Hsp90beta, which encodes one of two hsp90 isoforms, was not expressed in the surface fish or cavefish lens, whereas hsp70 was expressed in the lens of both forms, suggesting that neither is directly involved in lens apoptosis. In contrast, hsp90alpha, the other hsp90 isoform, was expressed in the cavefish but not the surface fish lens. Hsp90alpha expression peaked shortly before the beginning of lens apoptosis in three convergent cavefish populations, suggesting a close relationship with lens apoptosis. The absence of hsp90beta in the lens allowed us to use geldanamycin and radicicol, specific inhibitors of hsp90 chaperone function, to determine whether lens cell death requires hsp90alpha expression. Both inhibitors blocked TUNEL labeling in the cavefish lens, suggesting that hsp90alpha is required for apoptosis. In contrast to their effects on the lens, these inhibitors induced TUNEL labeling in the surface epidermis, presumably due to effects on hsp90beta function, implying that the two-hsp90 isoforms may have contrasting roles in cell survival. We conclude that hsp90alpha plays a novel role in lens apoptosis and cavefish eye degeneration.
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Affiliation(s)
- Thomas A Hooven
- Department of Biology, University of Maryland, College Park, MD 20742, USA
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Abstract
The integration of visual, lexical, and oculomotor information is a critical part of reading. Mr. Chips is an ideal-observer model that combines these sources of information optimally to read simple texts in the minimum number of saccades. This model provides a computational framework for interpreting human reading saccades in both normal and low vision. The purpose of this paper is to report performance of the model for conditions emulating reading with normal vision--a visual span of nine characters, multiplicative saccade noise with a standard deviation of 30%, and texts based on three full-length children's books. Comparison of fixation locations by humans and Mr. Chips revealed: (1) that both exhibit very similar word-skipping behavior; (2) both show initial fixations near the center of words, but with a systematic difference suggestive of an asymmetry in the human visual span; and (3) differences in the pattern of refixations within words that may uncover non-optimal lexical inference by human readers. A human context effect--30% difference in mean saccade size between continuous text and random sequences of words--was very similar to the 25% effect for the model associated with a corresponding difference in the predictability of text words. Overall, our findings show that many of the complicated aspects of human reading saccades can be explained concisely by early information-processing constraints.
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Affiliation(s)
- Gordon E Legge
- Minnesota Laboratory for Low-Vision Research, Department of Psychology, University of Minnesota, 75 East River Road, Minneapolis, MN55455, USA.
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