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Neonatal Infections. Questions?. Why are infants, especially prematures , more susceptible to infections? What are the clinical manifestations of neonatal infections? Bacterial ? Viral? How to prevent infections?. “ Prematurity is an infectious disease. ”. - James Todd, M.D.
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Questions? • Why are infants, especially prematures, more susceptible to infections? • What are the clinical manifestations of neonatal infections? • Bacterial? Viral? • How to prevent infections?
“Prematurity is an infectious disease.” - James Todd, M.D.
Why are infants, especially premies, more susceptible to infections?
Neonatal Immune System • All neonates relatively immunocompromised • Immature and Ineffective: • Antibodies • Complement • Neutrophils • Skin / mucosal barriers
Antibodies Infectious agent Immunity Figure 1.1 Antibodies (anti- foreign bodies) are produced by host while cells on contact with the invading micro-organism which is acting as an antigen (e.g. generates antibodies). The individual may then be immune to further attacks. (Modified From: Roitt, I: Essential Immunology, 4th edition, Blackwell Scientific Publications, 1980)
Antibodies Infectious agent Immunity x x No contact with infectious agents = no antibody production
Maternal Transfer of Antibodies • Antibody transfer increases with GA • Most during 3rd trimester • No guarantee maternal antibodies present to the infecting organism Remington and Klein, Sixth Edition, 2006
Neonatal Neutrophils • Immature • Chemotaxis • Deformability • Phagocytosis • Storage pool • Adults 14-fold > circulating pool • Neonates only 2-fold
“Normal” VLBW neonates Mouzinho et al, Pediatr 94:76, 1994
“Normal” VLBW neonates Mouzinho et al, Pediatr 94:76, 1994
Neonatal Anatomic Barriers • Immature skin and mucosal surfaces • layers • junctions between cells • secretory IgA • Umbilical cord • Breaches - catheters, tape
Invasive Fungal Dermatitis in a VLBW infant JL Rowen, Sem Perinatal 27:406-413, 2003
Neonatal Sepsis: Incidence • 2/1000 live births with culture proven sepsis • Bacterial / Viral / Fungal • 80% infants develop bacterial sepsis • 20% infants perinatally acquired viral infections • ~ 25% of infected infants have meningitis • Higher rate with preterm birth • 26/1000 preterm infants with BW < 1000g • 8-9/1000 preterm infants with BW 1000-2000g Remington and Klein, Sixth Edition, 2006
Neonatal Infections Sepsis Meningitis Pneumonia Otitis Media Diarrheal Disease UTI Osteomyelitis Suppurative Arthritis Conjunctivitis Orbital Cellulitis Cellulitis - - Omphalitis Bacterial / Viral / Fungal