Paediatrics chapters
Neonatal sepsis
Bacterial infection of the blood in the first month of life: early and late onset forms, maternal and baby risk factors, the organisms, the vague clinical signs, the septic screen and first-line antibiotics.
- Neonatal sepsis is systemic bacterial infection in the first 4 weeks: early onset (first 3 days, from the mother's genital tract) and late onset (day 4 to 1 month, from the environment and hospital).
- Signs are vague: poor feeding, lethargy, temperature instability, apnoea, grunting, poor perfusion, jaundice, bulging fontanelle; prematurity is the strongest risk factor.
- Take a blood culture (and LP if well enough) and start ampicillin plus gentamicin at once; use cefotaxime for meningitis and vancomycin for line-related late-onset infection.
On this page
Overview
Neonatal sepsis is a clinical syndrome of systemic illness caused by bacterial infection in the first four weeks of life, confirmed by a positive blood culture. It is one of the biggest killers of newborns: Akbar attributes about 40% of neonatal deaths in Pakistan to sepsis.
The signs are often subtle, so a low threshold for suspicion, early cultures and early antibiotics save lives.
Definition and classification
| Feature | Early onset sepsis | Late onset sepsis |
|---|---|---|
| Onset | First 3 days of life (Akbar; Nelson uses the first 7 days) | Day 4 to 1 month (Nelson: days 8-28) |
| Source | Maternal genital tract (before or during birth) | Environment: hands, equipment, lines, home |
| Typical organisms | E. coli, group B streptococcus (GBS), Listeria, Klebsiella | Klebsiella, Pseudomonas, Staphylococcus (aureus and coagulase-negative), E. coli, Candida |
| Presentation | Often respiratory distress and shock, pneumonia | Often meningitis, focal infection |
| Link | Maternal risk factors | Prematurity, lines, ventilation, poor hygiene |
Why newborns get sepsis
- Cellular immunity is weak: neutrophils move, engulf and kill poorly; few reserve neutrophils.
- Humoral immunity is weak: only IgG crosses the placenta, mostly in the last trimester, so preterm babies get little. IgM and IgA do not cross; low secretory IgA lets bacteria stick to the gut.
- Complement levels are low.
- Thin skin and mucosa, plus cannulas, tubes and catheters, open portals of entry.
Risk factors
Maternal (mainly early onset)
- Prolonged rupture of membranes: more than 18 hours (Akbar; Nelson uses more than 24 hours).
- Maternal fever in labour of 38°C or more.
- Chorioamnionitis (fever, uterine tenderness, foul liquor).
- Prolonged labour (more than 18 hours) and many vaginal examinations.
- Maternal colonisation with GBS or E. coli; maternal UTI.
- Poor socioeconomic status.
Baby and environment
- Prematurity: the single most important risk factor.
- Low birth weight, birth asphyxia.
- Home delivery, unclean delivery practices and poor cord care.
- Bottle-feeding instead of breastfeeding.
- Hospital factors: poor hand washing, IV lines and umbilical catheters, endotracheal tubes, TPN, long antibiotic courses.
Prematurity is the factor most strongly linked to neonatal sepsis; PROM over 18 hours and maternal fever of 38°C or more are the classic maternal risk factors.
Organisms
| Organism | Points |
|---|---|
| E. coli | Common in early onset sepsis and meningitis; Akbar lists it first |
| Group B streptococcus | With E. coli and Listeria, the main cause in Nelson (Western data); early onset pneumonia and late onset meningitis; colonises the maternal genital tract |
| Klebsiella | Nelson notes that gram-negative organisms such as Klebsiella are more common in less developed countries; often resistant |
| Listeria monocytogenes | Early onset; mother may have had a flu-like illness; ampicillin covers it (cephalosporins do not) |
| Staphylococcus aureus | Skin pustules, umbilicus, bones and joints |
| Coagulase-negative staphylococci | Line-related late onset sepsis in preterm babies |
| Pseudomonas | Hospital infection, ventilated babies |
| Candida | Long antibiotics, TPN, very low birth weight |
Cephalosporins do not cover Listeria. That is why ampicillin is part of first-line treatment of early onset sepsis.
Clinical presentation
Early signs are non-specific; the mother may simply say the baby is "not right".
| System | Signs |
|---|---|
| General | Refusal to feed, "not looking well", temperature instability (fever or hypothermia), oedema, sclerema |
| Neurological | Lethargy, irritability, hypotonia, jitteriness, high-pitched cry, seizures, bulging fontanelle, poor Moro |
| Respiratory | Apnoea, tachypnoea, grunting, flaring, recession, cyanosis |
| Cardiovascular | Tachycardia or bradycardia, mottling, cold peripheries, prolonged capillary refill, hypotension |
| Gastrointestinal | Vomiting, diarrhoea, abdominal distension, large gastric aspirates, hepatomegaly |
| Haematological and skin | Jaundice, pallor, petechiae, purpura, bleeding, splenomegaly; pustules, omphalitis |
| Metabolic | Hypoglycaemia or hyperglycaemia, metabolic acidosis |
- Sclerema (hard, cold, waxy skin) is a sign of severe sepsis.
- Hypothermia is more common than fever in septic preterm babies.
IMNCI: possible serious bacterial infection in a young infant
Any one of these in an infant under 2 months means very severe disease: give the first dose of IM antibiotics, prevent low blood sugar, keep warm and refer urgently.
- Not feeding well
- Convulsions
- Fast breathing (60 or more per minute)
- Severe chest indrawing
- Fever (37.5°C or more) or low temperature (below 35.5°C)
- Moves only when stimulated, or not at all
A red umbilicus with pus or skin pustules alone is a local bacterial infection, treated with oral antibiotics and home care.
Investigations
Take samples before antibiotics, but never delay antibiotics in a sick baby to collect them.
Definitive tests
- Blood culture: the gold standard. Take at least 1 mL with strict asepsis; sensitivity is only about 50-80%, so a negative culture does not exclude sepsis.
- Lumbar puncture (CSF): about one third of septic newborns have meningitis (Akbar; Nelson gives about 30% in early onset and up to 75% of late onset cases), which changes the drug and duration. Delay only if the baby is too unstable.
- Urine culture: mainly useful in late onset sepsis (little value in the first days).
- Tracheal aspirate in ventilated babies.
Septic screen (supportive tests)
| Test | Suggests sepsis |
|---|---|
| Total white count | Very high or low (Akbar: above 30,000 or below 4,000/mm3) |
| Absolute neutrophil count | Neutropenia (below 2,000/mm3); a bad sign |
| Immature to total neutrophil (I/T) ratio | 0.2 or more |
| Platelets | Below 150,000/mm3 |
| C-reactive protein | Raised; serial values help decide when to stop antibiotics |
| Procalcitonin | Raised |
| ESR | Raised (micro-ESR) |
Other tests: chest X-ray (respiratory signs), blood glucose, blood gases, electrolytes, bilirubin, coagulation screen.
Neutropenia is more worrying than a high count in a septic newborn, and a low platelet count is a common clue.
Management
Antibiotics
Start empirical antibiotics as soon as sepsis is suspected, then adjust to the culture result.
| Situation | First choice (Akbar doses) |
|---|---|
| Early onset sepsis | Ampicillin 100-300 mg/kg/day IV in 8-hourly doses plus gentamicin 5 mg/kg/day IV (every 8-12 hours) |
| Meningitis | Add or switch to a third-generation cephalosporin: cefotaxime 100 mg/kg/day IV (8-12 hourly) |
| Late onset or hospital sepsis, especially with long lines | Vancomycin 15 mg/kg/dose 8-hourly plus an aminoglycoside (for example amikacin 15 mg/kg/day) |
| Pseudomonas | Ceftazidime or a carbapenem |
| Resistant gram-negatives or recent cephalosporin use | Carbapenem |
| Anaerobes (for example NEC) | Add metronidazole or clindamycin |
| Fungal sepsis | Amphotericin B |
| Listeria | Ampicillin alone is adequate once confirmed |
| GBS | Penicillin alone is adequate once confirmed |
Duration:
| Infection | Duration |
|---|---|
| Bacteraemia | 10 days |
| GBS and uncomplicated meningitis | 14 days |
| Complicated gram-negative meningitis | 21-28 days |
Ceftriaxone displaces bilirubin from albumin and can raise the risk of kernicterus; cefotaxime is the cephalosporin of choice in newborns.
Antibiotic resistance is a growing problem in Pakistani neonatal units; follow your unit's antibiogram and the current national guidance.
Supportive care
- Neutral thermal environment; avoid hypothermia.
- Monitor vital signs, oxygen saturation, glucose and urine output.
- Fluids and electrolytes; correct hypoglycaemia, hypocalcaemia and acidosis.
- Oxygen and ventilation for respiratory failure or apnoea.
- Shock: fluid boluses and inotropes (dopamine); hydrocortisone for refractory shock.
- DIC: fresh frozen plasma and platelets.
- Treat seizures (phenobarbitone) and jaundice aggressively, because sepsis lowers the bilirubin level at which kernicterus occurs.
- Transfuse if anaemic; parenteral nutrition if feeds are not tolerated.
- Breast milk as soon as feeds are possible.
Complications
- Septic shock, DIC, multi-organ failure, death.
- Meningitis: acute ventriculitis, brain abscess; later hearing loss, hydrocephalus, cerebral palsy, epilepsy, developmental delay.
- Osteomyelitis and septic arthritis with residual deformity.
- Endocarditis, septic emboli, abscesses.
- Necrotising enterocolitis.
- Candidaemia after long antibiotic courses.
Case fatality is high, about 20-50% in Akbar.
Late complications of neonatal meningitis include sensorineural hearing loss, so every survivor needs a hearing test.
Prevention
- Hand washing: the single simplest measure in nurseries.
- Clean delivery: clean hands, clean surface, clean blade, clean cord tie; promote facility births.
- Exclusive breastfeeding and chlorhexidine cord care in home births.
- Intrapartum antibiotic prophylaxis for mothers colonised with GBS or with risk factors, and prompt treatment of chorioamnionitis.
- Maternal immunisation (tetanus, hepatitis B, rubella).
- Careful asepsis with lines; remove lines early; sensible antibiotic use.
- Kangaroo mother care for small babies.
"Hands, Breast, Clean cord": the three cheapest ways to stop neonatal sepsis.
Expect: early onset sepsis in the first 3 days versus late onset from day 4; PROM over 18 hours, maternal fever and chorioamnionitis as risk factors; prematurity as the strongest risk factor; E. coli, GBS and Listeria in early onset; vague signs such as poor feeding, temperature instability and apnoea; blood culture as gold standard; I/T ratio, neutropenia, low platelets and CRP in the septic screen; LP because one third have meningitis; ampicillin plus gentamicin as first-line; cefotaxime for meningitis and avoidance of ceftriaxone; IMNCI danger signs in young infants; hand washing and breastfeeding for prevention.
Quick revision
- Early onset: first 3 days, maternal organisms (E. coli, GBS, Listeria).
- Late onset: day 4 to 1 month, hospital and environment (Klebsiella, staphylococci, Pseudomonas).
- Risks: prematurity, PROM over 18 h, maternal fever 38°C or more, chorioamnionitis, home delivery.
- Signs: poor feeding, temperature instability, apnoea, lethargy, jaundice, mottling.
- Blood culture is the gold standard; LP in all who are stable enough.
- Septic screen: I/T 0.2 or more, low neutrophils, platelets below 150,000, raised CRP.
- Ampicillin + gentamicin; cefotaxime for meningitis; vancomycin for line sepsis.
- 10 days bacteraemia; 14 days GBS and meningitis; 21-28 days complicated gram-negative meningitis.
Written by The House Job from standard references (Basis of Paediatrics by Pervez Akbar; Nelson Essentials of Paediatrics).
FAQ
What is the difference between early and late onset neonatal sepsis?
Early onset starts in the first 3 days and comes from the mother's genital tract; late onset starts from day 4 and comes from the environment or hospital.
Why is ampicillin included in first-line treatment?
It covers Listeria and GBS, and Listeria is not covered by cephalosporins.
Why do a lumbar puncture in a septic newborn?
About a third of septic newborns have meningitis, which needs a cephalosporin and a longer course.
Does a negative blood culture rule out sepsis?
No; blood culture picks up only about half to four fifths of cases, so a sick baby is treated on clinical grounds.