Immunogenetic, pharmacological and neurodevelopmental aspects of nosocomial sepsis and meningitis in preterm infants.

Nosocomial sepsis is a major contributor to risk of death, poor
neurodevelopment and growth impairment in preterm and small for gestational age
(SGA) infants. The immunological basis for the increased susceptibility to
severe bacterial infections in preterm infants is only partially understood.
Their immature innate immune system is characterized by decreased neutrophil
and monocyte activity, reduced concentrations of complement factors, and
decreased production of pro-inflammatory cytokines. Furthermore, toll-like
receptors (TLRs) may play an important role in recognition of microbes. Reduced
expression of the TLRs surface proteins may impair VLBW infants to boost
initial immune response and contribute to the susceptibility to infections with
bacteria. Also, genetic variation in the innate immune system of the host may
play a role in susceptibility to infection or poor outcome after infection. It
is postulated that exposure of the preterm brain to inflammatory mediators
during infectious episodes contributes to brain injury and poor
neuropsychodevelopmental outcome, including cerebral palsy.
For the analysis of bacterial sepsis, bacterial blood culture is the gold
standard for many years. Broad spectrum antibiotic therapy is given while
awaiting the 48 hours preliminary result of culture. A real-time PCR with high
specificity and sensitivity is currently available to identify and quantify
bacterial DNA, which is a rapid diagnostic tool that even can be used to
identify pathogens which are under the detection limit by culture techniques.
Most currently recommended dosing guidelines for antibiotics in neonates are
not based on the level of evidence. Future prospective studies are warranted in
order to improve our current knowledge on early detection of neonatal sepsis
and treatment, particularly drug dosing and drug safety in preterm infants.
This may not only lead to a decrease in short-term morbidity and mortality, but
may also improve long-term future outcome substantially.


Supplement 27-09-2013:
Sepsis also has adverse effects on autoregulation and possibly on cerebral
activity. This combined with the effects of inflammatory mediators may cause
white matter injury and thereby influence longterm outcome.

1. To identify and specify bacteria by using RT-PCR on blood and cerebrospinal
fluid (CSF) in preterm infants, having nosocomial sepsis and meningitis.
2. To compare RT-PCR (see aim 1) with the gold standard bacterial culture in
preterm infants, having nosocomial sepsis and meningitis.
3. To study the inflammatory response (cytokines, TLR's) of preterm infants in
relation to different bacteria and bacterial load, measured by RT-PCR, and in
relation to different polymorphisms.
4. To study antibiotic concentrations in plasma of preterm infants having
nosocomial sepsis and/or meningitis, and to describe the relationships between
plasma concentration and pharmacodynamic effects.
5. To investigate the influence of specific co-variates on pharmacodynamics and
pharmacokinetics of antibiotics in preterm infants.
6. To investigate the association between nosocomial sepsis and meningitis on
neuropsychodevelopmental outcome during the first 2 years of life, and growth
and body composition in preterm infants.

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Objectives:
1. To investigate the changes in cerebral perfusion/ oxygenation during
nosocomial sepsis/ meningitis in preterm infants.
2. To investigate the effect of nosocomial sepsis/ meningitis in preterm
infants on electroencephalographic background patterns and seizure activity.
3. To relate changes in the cerebral perfusion during nosocomial sepsis/
meningitis in preterm infants to ultrasound findings (normal or abnormal).
4. To relate changes in ultrasound examination to microorganisms (by
bloodculture or PCR) and/or cytokine release.
5. To relate neuropsychodevelopmental outcome at two years of age (corrected
for prematurity) to changes in cerebral perfusion and the encephalographic
background patterns and/ or epileptic activity in preterm infants with
established nosocomial sepsis/ meningitis.

Prospective observational study during a consisting intervention.

Each participant will be studied for 2 days after the onset of the
sepsis/meningitis. At fixed time points (8 in number) blood will be collected
from an indwelling arterial catheter, which is routinely inserted during
sepsis/meningitis. In rare cases in which an arterial catheter is not inserted,
blood will be collected by puncture, which will be combined with punctures for
routine treatment if possible. In total, a minimum of 1.9 mL and a maximum of
3.9 mL of blood per patient will be collected, depending on which antibiotics
are administered to the patient. Cerebrospinal fluid (CSF) is collected by
lumbar puncture as a part of routine sepsis-workup. For the study 0.2 mL of
extra CSF is collected during the same procedure. Buccal mucosa scraping is
performed once for detection of genetic polymorphisms. After discharge from the
department follow up is performed according to routine follow up of preterms in
the VU University Medical Center.

Addendum 19/10/2012: to validate the PCR's on bacteria we want to use residual
material from patients who are or were in the ICU Neonatology and do not
participate in the study. This material (blood / CSF) is no longer used for
clinical purposes and is normally discarded.

Supplement 27-09-2013:
During 72 hours 6 needle-elctrodes will be placed subcutaneously on the head
and a non-invasive sensor will be placed on the forehead. This will be a
minimal burden for the patient and induce no risk.