Paediatric Microbiology

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Paediatric Microbiology

• Dr Amy Chue
• ID/Microbiology Registrar
• Dr Peter Munthali
• Consultant Microbiologist

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Objectives

• By the end of this session you should be able to
• Distinguish between the common causes of
  infections in the neonate and older children
• Relate maternal infections to neonates
• Interpret CSF findings in relation to clinical
  presentation in neonates
• Demonstrate rational use of antibiotics in
  neonatal sepsis with regard to possible causative
  organisms

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Case One

• 3 week old baby born at 39/40
• Normal vaginal delivery
• Healthy and feeding well initially
• Upset and crying
• Bulging fontanelle noted by parents
• Taken to ED
• Hx admitted a week earlier with bronchiolitis
  and discharged with no antibiotic treatment

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Results

• CSF
• Clear and colourless
• RBC 84x106/L
• WCC 236x106/L
• Gram stain organisms not seen
• Glucose 3.1 mmol/L
• Protein 1.4 g/L (0.15 0.45)
• FBC
• Hb 101g/L (111 141g/L)
• WCC 24.85 x 109/L (6 18.0 x 109/L)
• CRP 46mg/L (lt11mg/L)

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Questions

• What is the possible microbiological diagnosis?
• What antibiotics would you consider commencing
  and why?

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Microbiology
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Management

• Amoxicillin based regime for 14 days
• Vaccination (2/12, 4/12, 12/12)

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Case Two

• 1 day old baby born at 365
• Floppy at birth
• Mother had fever during labour and received some
  antibiotics
• Baby started on Cefotaxime and Amoxicillin

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Investigations

• LP
• Gram
• Turbid CSF
• RBC 6x106/L
• WCC 1046x106/L 90 Poly
• Glucose 1.9mmol/L
• Protein 1.30g/L (0.15 0.45g/L)
• No organism seen
• CRP 164
• FBC
• HB 93g/l
• WCC 13.09x109/L (6.0 18.0)
• Blood culture Gram positive cocci ?type

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Questions

• What is the diagnosis?
• What is the possible microbiological diagnosis?
• Is this infection preventable?
• Should antibiotics regime be changed?
• If so, how?

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Organisms

• Group B Streptococcus
• Streptococcus agalactiae

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Management

• Penicillin based regime (Benzylpenicillin Vs
  Amoxicillin)
• Prophylactic antibiotics given during labour
• Cefotaxime as blind treatment for neonate

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Case Three

• 7 day old baby born at term
• Normal vaginal delivery
• Presents with fever, irritability and poor feeding

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Investigations

• FBC
• Hb 115g/l
• WCC 24.85x109/L
• CRP 12
• Blood cultures Gram positive bacilli

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Questions

• What is your microbiological diagnosis?
• How would you manage the case
• Antibiotics
• Infection control

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Diagnosis

• Listeria monocytogenes

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Listeria monocytogenes

• Gram positive bacillus
• Pregnant women particularly at risk
• Certain at risk foods
• Inherently resistant to cephalosporins

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Management

• Amoxicillin for 14 - 21 days
• Infection control isolation

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Case Four

• Baby born at 38 wks, 2.6Kg
• Mother had episiotomy
• Baby discharged well on day 2
• Readmitted on day 7 with
• Wt loss
• Poor feeding
• Abnormal limb movements
• EEG no seizure activity

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Investigations

• CRP 158
• CSF
• Cell count normal
• Glucose normal
• Protein 0.85g/L (0.15-0.45g/L)
• Clotting deranged
• Low platelets
• LFTs deranged
• CT extensive bleeding on brain and evidence of
  hypoxic injuries

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Treatment

• Initial treatment Benzylpenicillin and
  Gentamicin
• Modified treatment Meropenem and Vancomycin

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Further investigations and treatment

• What further investigations should be done
• On CSF
• On Blood
• What is the possible diagnosis?
• Is the current antibiotic regime adequate?

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Further Results

• CSF PCR HSV 1 positive
• Blood PCR HSV 1 positive

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HSV infection in neonates

• Usually peri natal and post natal
• 45 skin, eyes and mouth infections
• 20 CNS infection
• 25 disseminated HSV
• Symptoms
• Irritability
• Seizures
• Respiratory distress
• Jaundice
• Coagulopathy
• Pneumonitis

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HSV in neonates

• Rx high dose aciclovir
• Rx women with lesions
• Suppressive therapy
• Consideration of C-section
• BASHH guidelines

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Key points

• Possible organisms causing neonatal sepsis
• Group B Streptococcus
• Group A Streptococcus
• E.coli
• Listeria monocytogenes
• Antibiotic treatment
• If Listeria is suspected, must consider
  penicillin based regime
• Important to consider maternal infection