Neonatal Sepsis

Overview & Definition

Neonatal sepsis is a systemic inflammatory response syndrome (SIRS) in response to a documented or suspected infection occurring within the first 28 days of life. It is one of the leading causes of neonatal mortality worldwide, accounting for an estimated 1 million neonatal deaths each year globally, the majority in low- and middle-income countries.[5][10]

The clinical skill is not the diagnosis (which is syndromic) but three things: (1) recognising that an unwell neonate may be septic — the presentation is so non-specific that any deviation from normal feeding, temperature, alertness or breathing pattern in the first 28 days should trigger a sepsis evaluation; (2) stratifying risk by timing (early- vs late-onset), maternal risk factors and gestation; (3) delivering empirical IV antibiotics within 1 hour of suspicion, with cultures drawn beforehand — every hour of delay measurably increases mortality.[4][6]

Neonatal sepsis sits within a broader differential that includes focal neonatal infections (pneumonia, meningitis, osteomyelitis, omphalitis, conjunctivitis, necrotising enterocolitis) and must be distinguished from non-infective mimics — most importantly respiratory distress syndrome (RDS), congenital heart disease, inborn errors of metabolism and congenital (TORCH) infection.[2]

Classification

By timing of onset (the classification that decides empirical antibiotics):[3][1]

• Early-onset sepsis (EOS) — onset within the first 72 hours of life (UK NICE / international convention) or, in the AAP/CDC convention, the first 7 days of life. Caused by organisms acquired vertically, ascending from the maternal genital tract either in utero (after prolonged rupture of membranes, chorioamnionitis) or during passage through the birth canal. The 'big three' organisms are Group B Streptococcus (GBS, Streptococcus agalactiae), E coli (especially K1 capsular type), and Listeria monocytogenes. In low- and middle-income countries, Klebsiella pneumoniae and other Gram-negatives additionally dominate.
• Late-onset sepsis (LOS) — onset after 72 hours (UK) or after 7 days (US convention). Acquired horizontally — from the hands of carers, contaminated equipment, central venous catheters, total parenteral nutrition (TPN), mechanical ventilation, or the community. The predominant organisms are coagulase-negative staphylococci (CoNS, mostly Staphylococcus epidermidis) — classically line-associated, Staphylococcus aureus (including MRSA), Klebsiella, E coli, Pseudomonas, and — in VLBW infants — Candida. [1]

By clinical syndrome — neonatal sepsis may present as: isolated septicaemia; septicaemia with pneumonia, meningitis, osteomyelitis or septic arthritis, omphalitis (umbilical infection), conjunctivitis, or necrotising enterocolitis. Focal signs help direct investigations and broaden empirical cover. [1]

By severity — neonatal septic shock is defined as sepsis plus cardiovascular organ dysfunction (hypotension despite adequate fluid, or need for inotropes, or capillary refill over 3 s, or serum lactate over 2 mmol/L). Severity scoring is by SNAPPE-II (Score for Neonatal Acute Physiology with Perinatal extension II) in NICU. [1]

Epidemiology & Risk Factors

Neonatal sepsis is a leading infectious cause of neonatal death worldwide.[5][10]

Maternal and perinatal risk factors (the EOS risk triad):[3][8]

• Maternal GBS colonisation (5-30% of pregnant women) — single biggest EOS risk factor; addressed by universal screening at 35-37 weeks and intrapartum antibiotic prophylaxis.
• Chorioamnionitis — clinical diagnosis: maternal intrapartum fever over 38°C plus two or more of fetal tachycardia, maternal tachycardia, uterine tenderness, foul-smelling amniotic fluid, maternal leucocytosis over 15,000.
• Prolonged rupture of membranes (PROM) — over 18 hours is the conventional threshold.
• Prematurity — risk is inversely proportional to gestational age.
• Low birth weight (LBW) and very-low-birth-weight (VLBW, under 1500 g).
• Maternal urinary tract infection with GBS in pregnancy.
• Previous infant with invasive GBS disease. [1]

Late-onset risk factors:[4]

• Central venous catheter (umbilical, peripherally inserted central, Broviac/Hickman) — accounts for the dominance of CoNS in LOS.
• Total parenteral nutrition (TPN) including lipid emulsion — promotes coagulase-negative staph and Candida.
• Mechanical ventilation and endotracheal tubes.
• Prolonged hospital stay (NICU, special care baby unit).
• Surgical procedures (NEC, abdominal wall defects).
• Formula feeding (versus breast milk — protects via secretory IgA, lactoferrin, oligosaccharides).
• Invasive procedures, parenteral medications, inadequate hand hygiene. [1]

Pathophysiology

The neonate — particularly the preterm — is immunocompromised by definition. Multiple arms of innate and adaptive immunity are functionally immature:[1][4]

Quantitative and qualitative neutrophil deficiency. Neonatal neutrophils show impaired chemotaxis, reduced phagocytosis, and a defective oxidative (respiratory) burst. Neonatal neutrophil stores in the bone marrow are also small, so a septic neonate quickly exhausts neutrophil reserves — the leukopenia/neutropenia of neonatal sepsis is itself a poor prognostic marker. The immature-to-total (I:T) neutrophil ratio over 0.2 reflects the bone marrow pouring band forms into circulation. [1]

Immunoglobulin deficiency. IgG crosses the placenta actively via FcRn receptor, but most transfer occurs in the third trimester — a baby born before 32-34 weeks has substantially lower IgG than a term baby. IgM does not cross the placenta (it is pentameric), and the neonate cannot mount a brisk IgM response to a new antigen. Secretory IgA is absent from the gut unless breastfed. [1]

Complement immaturity. Neonatal C3, factor B, and alternative pathway activity are approximately half of adult values, limiting opsonisation of organisms such as GBS. [1]

Pattern-recognition receptor immaturity. Toll-like receptor (TLR) expression, particularly TLR2 and TLR4 on neutrophils and antigen-presenting cells, is reduced; downstream signalling (NF-kB activation, cytokine release) is blunted. This hypo-inflammatory early phase can rapidly tip into a hyper-inflammatory late phase as cytokines accumulate.[4]

Barrier immaturity. The skin is thin and easily breached (especially at the umbilicus and around central lines); the gut mucosal barrier is immature, allowing bacterial translocation; the blood-brain barrier is also immature, partly explaining why neonatal sepsis seeds the meninges so readily (meningitis complicates 10-30% of EOS).[3]

Route of acquisition drives the organism: [1]

• EOS — vertical transmission. Organisms ascend from the vagina through ruptured or even intact membranes, colonise the amniotic cavity, and are aspirated or swallowed by the fetus, seeding the lungs and bloodstream. Alternatively, the neonate is colonised during passage through the birth canal and develops bacteraemia shortly after birth. The causative organisms reflect the maternal vaginal/rectal flora — hence GBS, E coli K1, Listeria.[8]
• LOS — horizontal/nosocomial transmission. Organisms reach the neonate via the hands of carers, contaminated equipment, central venous catheters, endotracheal tubes, or feed. The biofilm-forming capacity of CoNS explains its dominance in line-associated sepsis.[4]

Once bacteraemic, organisms multiply, triggering a cytokine cascade — IL-6, IL-1beta, TNF-alpha, IL-8 — that produces vasodilation, capillary leak, myocardial depression, disseminated intravascular coagulation (DIC), and ultimately multi-organ dysfunction syndrome (MODS). The clinical phenotype is shock, respiratory failure, coagulopathy, metabolic acidosis, hypoglycaemia and hypothermia.[1]

Clinical Presentation

The single most important fact about neonatal sepsis is that the presentation is non-specific. A neonate cannot localise symptoms. Any one of the following — alone or in combination — in the first 28 days should trigger a sepsis evaluation:[1][1]

[1]

Atypical presentation in the premature / VLBW neonate — apnoea, temperature instability, glucose instability, feeding intolerance, or an unexplained rise in ventilator/oxygen requirements may be the only signs. Hypothermia in a preterm is more ominous than fever.[4]

Differential Diagnosis

Any one of these can mimic sepsis, and sepsis can mimic any of them. Distinguishing features:[2]

• Respiratory distress syndrome (RDS) — preterm, surfactant deficiency; classic ground-glass / reticulogranular CXR with air bronchograms; onset within minutes of birth; improves with surfactant and CPAP; no maternal risk factors for infection. However, neonatal pneumonia and RDS are radiologically and clinically indistinguishable — empirically treat as sepsis if any infection risk factor exists.
• Transient tachypnoea of the newborn (TTN) — term or near-term, especially after elective caesarean section without labour; self-limiting tachypnoea resolving within 24-72 h; CXR shows fluid in the fissures and perihilar streaking; benign course.
• Congenital heart disease (duct-dependent lesions) — differential cyanosis (right-to-left ductal shunt), abnormal pre- and post-ductal saturations (gap over 5%), murmurs (may be absent), weak or absent femoral pulses (coarctation), responds to prostaglandin E1 (alprostadil); CXR/echocardiography diagnostic.
• Meconium aspiration syndrome (MAS) — meconium-stained liquor, term or post-term, respiratory distress from birth, coarse nodular infiltrates and hyperinflation on CXR.
• Inborn errors of metabolism (IEM) — persistent metabolic acidosis with high anion gap, hyperammonaemia, hypoglycaemia with ketosis, neurological deterioration, family history of consanguinity or neonatal death; Tandem mass spectrometry / plasma amino acids / urine organic acids diagnostic.
• Neonatal abstinence syndrome (NAS) — maternal opiate/SSRI/benzodiazepine history; tremor, high-pitched cry, sneezing, yawning, loose stools, hypertonia; resolves over days-weeks.
• Congenital infection (TORCH — toxoplasma, other [syphilis, varicella, parvovirus], rubella, CMV, HSV) — usually chronic, with hepatosplenomegaly, petechiae (blueberry-muffin rash from extramedullary haematopoiesis), chorioretinitis, intracranial calcifications, intrauterine growth restriction (IUGR), cataracts; specific serology/PCR diagnostic.
• Hypoglycaemia — jitteriness, seizures, apnoea; bedside glucose under 2.6 mmol/L.
• Hypothermia from environmental cause — resolves with warming.
• Necrotising enterocolitis (NEC) — abdominal distension, bloody stools, abdominal wall erythema, pneumatosis intestinalis on AXR; overlaps with sepsis. [1]

Always remember: a septic neonate can present with any combination of these mimics. When in doubt, treat empirically.[1]

Clinical & Bedside Assessment

ABCDE systematic assessment:[1]

• Airway — patency; secretions; meconium.
• Breathing — rate (normal neonate 40-60/min; tachypnoea over 60, apnoea); effort (grunting, nasal flaring, subcostal/intercostal/sternal recession); auscultation (symmetry, crackles, wheeze); SpO2 (target 91-95% in preterm, 95-100% in term; differential pre- and post-ductal if congenital heart disease suspected); work of breathing.
• Circulation — heart rate (normal 110-160; tachycardia over 160, bradycardia under 100 ominous); capillary refill (central sternum, normal under 2 s; peripheral toe, normal under 3 s — over 3 s is abnormal); pulses (bound femorals to exclude coarctation); blood pressure (mean BP approximately gestational age in weeks; hypotension a late sign); skin colour (pallor, mottling, acrocyanosis, central cyanosis).
• Disability — tone, alertness, activity, seizures; anterior fontanelle (flat, sunken, bulging); pupils; AVPU/GCS.
• Exposure — full head-to-toe: skin (pustules, cellulitis, petechiae/purpura suggesting DIC), umbilicus (redness, discharge — omphalitis), eyes (conjunctival discharge), joints and long bones (warmth, swelling, pseudoparalysis — reduced movement of a limb suggests osteomyelitis or septic arthritis), abdomen (distension, tenderness, hepatosplenomegaly). [1]

Look for shock: tachycardia disproportionate to fever, cold peripheries with central pallor, prolonged capillary refill, weak pulses, mottled skin, oliguria, altered sensorium, hypotension. Hypotension is a late sign in neonates — perfusion must be assessed early.[1]

Calculate weight-based doses for every drug; neonatal doses are per kg and often per gestational age. [1]

Investigations

Take the cultures BEFORE antibiotics. Every minute of antibiotic exposure lowers the yield of the blood culture. The minimal septic screen in a suspected neonatal sepsis case consists of:[6][1]

Blood

• Blood culture (gold standard) — aseptic venepuncture, 1 mL of blood, into aerobic and anaerobic paediatric bottles; the single most important diagnostic test. Approximately 1-10% of clinically diagnosed neonatal sepsis is culture-positive.
• CRP (C-reactive protein) — acute-phase reactant; rises after 12-24 hours. A single CRP has limited sensitivity early; serial CRP at 24 and 48 hours improves diagnostic performance (CRP over 10 mg/L supportive, two normal CRPs 24 h apart have high negative predictive value for stopping antibiotics).
• Procalcitonin — rises earlier than CRP (within 6 hours); useful in early EOS.
• Presepsin (sCD14-ST) — novel early marker with high sensitivity for EOS; meta-analysis shows superior diagnostic accuracy to CRP and procalcitonin.[9]
• Full blood count — leukopenia under 5,000 or leukocytosis over 25,000; neutropenia (absolute neutrophil count) under 1,500; thrombocytopenia under 100,000. Hypoproliferative indices suggest bone marrow exhaustion (severe sepsis).
• Immature:Total (I:T) neutrophil ratio — over 0.2 is supportive of sepsis; over 0.3 strongly supportive. Use Manroe / Mouzinho nomograms for gestation-specific reference ranges.
• Blood gas — venous/arterial: metabolic acidosis (base deficit over 10), hypercapnia, hypoxaemia; serum lactate over 2 mmol/L suggests tissue hypoperfusion.
• Glucose — hypoglycaemia common.
• U&E, LFTs, coagulation (PT, aPTT, fibrinogen) — to detect AKI, hepatitis, DIC (prolonged PT/aPTT, low fibrinogen, raised D-dimer).

Lumbar puncture (when stable)

• CSF — microscopy (cell count, differential), protein (raised in neonate over 1.0 g/L), glucose (low, under 0.6 of blood glucose), Gram stain, culture, and where available PCR for HSV and enterovirus.
• Indications: any neonate with EOS, abnormal neurological signs, seizures, bulging fontanelle, or positive blood culture with organism known to seed meninges (GBS, E coli, Listeria).
• Defer if unstable — coagulopathy (platelets under 50,000 or PT over twice normal), cardiorespiratory instability, raised ICP — start antibiotics first, do LP when stabilised. [1]

Urine

• Culture — collected by suprapubic aspirate (SPA) or urethral catheterisation. Bag urine is NOT acceptable (contaminated by skin flora). Any growth from SPA is significant; catheter over 10,000 CFU/mL.
• More important in late-onset sepsis (UTI in neonate often co-presents).

Imaging

• Chest X-ray — pneumonia, RDS, effusion, heart size.
• Abdominal X-ray — if NEC suspected (pneumatosis intestinalis, portal venous gas).

Rapid pathogen tests

• GBS PCR / latex agglutination on CSF or urine; HSV PCR on CSF; enterovirus PCR.

Maternal and perinatal data

• GBS status (vaginal-rectal swab at 35-37 weeks), intrapartum fever, duration of ROM, antenatal antibiotics, gestation, birth weight, Apgars.

Named scoring tools

[1]

Management — Resuscitation

Time-critical. Antibiotics within 1 hour of suspicion is the single most important intervention.[6][1]

1. ABCDE: secure airway; oxygen to maintain SpO2 91-95% (term) or per local unit targets; escalate to nasal CPAP (5-7 cmH2O) or intubation and mechanical ventilation for respiratory failure (rising CO2, recurrent apnoea, severe distress).
2. Vascular access immediately — umbilical venous catheter (UVC) or peripheral cannula; umbilical arterial catheter (UAC) for BP monitoring if unstable.
3. Empirical IV antibiotics within 1 HOUR of suspicion — do not wait for investigations, including LP. Draw blood culture first.
4. Fluid resuscitation for shock: 10 mL/kg 0.9% sodium chloride over 10-20 minutes, reassess (heart rate, perfusion, liver size, chest for gallop, oxygenation); repeat up to total 30 mL/kg in the first hour; avoid over-resuscitation which worsens heart failure in the neonatal myocardium.
5. Inotropes for fluid-refractory shock: dopamine 5-20 mcg/kg/min first-line; dobutamine for myocardial dysfunction; adrenaline 0.05-1 mcg/kg/min or noradrenaline for refractory shock; titrate to mean BP approximately equal to gestational age in weeks and adequate perfusion.
6. Correct hypoglycaemia: 2 mL/kg 10% dextrose bolus, then continuous infusion 60-80 mL/kg/day of 10% dextrose.
7. Correct hypothermia: warm the infant (incubator, radiant warmer, Kangaroo Mother Care if stable).
8. Transfuse platelets for thrombocytopenia under 30,000 (or under 50,000 with bleeding) and fresh frozen plasma / cryoprecipitate for DIC.
9. Phototherapy / exchange transfusion for significant hyperbilirubinaemia (sepsis both causes haemolysis and impairs conjugation).
10. Ventilation, surfactant if secondary RDS/ARDS. [1]

Surviving Sepsis Campaign paediatric 2020: empirical broad-spectrum IV antibiotics within 1 hour for septic shock, within 3 hours for sepsis without shock.[1]

Management — Definitive & Stepwise

Empirical antibiotics are timing- and risk-driven:[1][6][1]

Empirical antibiotic regimens by syndrome

Doses shown are typical starting empirical doses — always verify against current local formulary (BNF for Children / NeoFax / NNF) and adjust for gestational age and renal function. [1]

Duration of therapy

• Culture-negative, clinically well, CRP normal at 48 h — stop antibiotics (antibiotic stewardship).
• Uncomplicated EOS (organism-sensitive) — 7 days.
• Gram-negative sepsis or complicated course — 10-14 days.
• GBS meningitis — 14-21 days.
• Gram-negative meningitis — minimum 21 days (some authorities 28).
• Listeria monocytogenes meningitis — 14-21 days of ampicillin (with gentamicin for synergy in the first week).
• Staphylococcal line sepsis — 7-14 days after line removal; longer if endocarditis/osteomyelitis. [1]

Source control

• Remove infected central venous catheters (especially with CoNS, S aureus, Candida, Gram-negative bacteraemia) — bacteraemia persisting over 24-72 h despite antibiotics is an indication for line removal.
• Drain focal collections (empyema, abscess, septic arthritis). [1]

Adjunctive and supportive therapy

• IVIG: not routinely recommended; reserved for severe disease on case-by-case basis.
• Granulocyte colony-stimulating factor (G-CSF): experimental, not standard; considered in neutropenic shock.
• Hydrocortisone 1 mg/kg 6-hourly for catecholamine-resistant shock with suspected adrenal insufficiency (VLBW).
• Breast milk preferred over formula — confers secretory IgA, lactoferrin, oligosaccharides, and reduces LOS and NEC. [1]

Prevention (key exam topic)

[1]

Maternal intrapartum antibiotic prophylaxis (IAP) for GBS:[7][8]

• Indication: GBS colonisation in current pregnancy, GBS bacteriuria in pregnancy, previous infant with invasive GBS disease, unknown GBS status with risk factors (preterm labour under 37 weeks, ROM over 18 hours, intrapartum fever over 38°C).
• Drug: IV benzylpenicillin G — loading dose 3 g (5 million units) then 1.5 g (2.5 million units) every 4 hours until delivery. Penicillin is preferred because GBS remains universally penicillin-sensitive.
• Penicillin allergy — IV clindamycin 900 mg 8-hourly if low anaphylaxis risk; IV vancomycin 1 g 12-hourly if high anaphylaxis risk or known clindamycin-resistant GBS.
• Effective only if given at least 4 hours before delivery. [1]

Specific Subtypes & Scenarios

• Group B Streptococcal sepsis — the prototype EOS organism; early-onset disease presents as pneumonia and/or septicaemia within 24-72 h, late-onset GBS presents as bacteraemia, meningitis, osteomyelitis or septic arthritis. Maternal IAP has reduced early-onset disease by approximately 80% in countries with universal screening.[8]
• Gram-negative (E coli K1, Klebsiella) sepsis — higher case-fatality; often complicated by meningitis (especially E coli K1); in LMIC these organisms are dominant and frequently ESBL-producing, requiring piperacillin-tazobactam or carbapenem empirical cover.[1]
• Listeria monocytogenes — acquired from unpasteurised dairy, soft cheese, deli meats, contaminated refrigerated foods; causes granulomatosis infantiseptica (disseminated abscesses with characteristic granulomas); treatment is ampicillin with gentamicin synergy; cephalosporins do NOT cover Listeria.
• Coagulase-negative staphylococcal (CoNS) sepsis — typically line-associated in VLBW preterm infants on TPN; biofilm formation makes eradication difficult without line removal; treat with vancomycin and remove the line if persistent bacteraemia.
• Staphylococcus aureus sepsis — including MRSA; more aggressive, may cause pneumatoceles, osteomyelitis, skin/soft tissue abscesses, scalded skin syndrome; cover with vancomycin (MRSA) or flucloxacillin (MSSA).
• Candida sepsis — VLBW/ELBW infants on broad-spectrum antibiotics, TPN and central lines; fluconazole first-line, amphotericin B if resistant; high mortality and neurodevelopmental sequelae — remove central line.
• Omphalitis (umbilical sepsis) — S aureus, S pyogenes, Gram-negatives, rarely Clostridium tetani (neonatal tetanus in unvaccinated communities); signs: redness, discharge, bleeding from cord; can spread rapidly to abdominal wall and peritonitis — treat aggressively.
• Neonatal tetanus — Clostridium tetani via umbilical stump in unhygienic delivery, unvaccinated mother; presents 3-14 days after birth with trismus, spasms, opisthotonos, inability to suck; treat with human tetanus immunoglobulin, IV penicillin / metronidazole, muscle relaxants, ventilation, and prevent with maternal tetanus toxoid vaccination.
• Necrotising enterocolitis (NEC) — overlaps with sepsis; triad of feeding intolerance, abdominal distension, bloody stools; pneumatosis intestinalis on AXR; broad-spectrum antibiotics (ampicillin + gentamicin + metronidazole); surgery for perforation.
• Osteomyelitis and septic arthritis in the neonate — S aureus, GBS; classically presents as pseudoparalysis (refusal to move a limb), swelling, irritability on handling; multi-focal in neonate due to intra-articular metaphyseal blood supply; treat with prolonged IV antibiotics.

Complications & Pitfalls

Acute:

• Septic shock with multi-organ dysfunction syndrome (MODS).
• DIC with petechiae, purpura, bleeding from puncture sites, intracranial haemorrhage.
• ARDS, pulmonary hypertension, respiratory failure.
• Acute kidney injury from shock and nephrotoxic drugs.
• Necrotising enterocolitis.
• Electrolyte and metabolic derangements: hypoglycaemia, hypocalcaemia, metabolic acidosis, SIADH. [1]

Long-term (especially after meningitis):

• Hearing loss (mandatory pre-discharge hearing screen / ABR).
• Cerebral palsy (periventricular leukomalacia).
• Neurodevelopmental delay, cognitive impairment.
• Post-meningitic hydrocephalus, epilepsy, cortical blindness. [1]

Classic pitfalls:[4][1]

• Delaying antibiotics while waiting for cultures or LP — the single biggest cause of preventable mortality.
• Treating the fever, missing sepsis — non-specific signs attributed to "cold", "feeding problem", or "jaundice".
• Accepting a bag urine as a urine culture — contaminated; leads to false-positive cultures and unnecessary antibiotics.
• Forgetting Listeria — covers only with ampicillin, not cephalosporins; consider in maternal ingestion of unpasteurised foods.
• Not removing an infected central line — bacteraemia with CoNS, S aureus, Candida and Gram-negatives often persists until line is out.
• Over-treating with prolonged antibiotics for culture-negative illness — drives resistance and gut dysbiosis.
• Missing meningitis because the fontanelle is soft or LP was deferred — repeat LP / image if clinical suspicion persists.

Prognosis & Disposition

Term infant with early appropriate therapy: excellent — most recover without sequelae. [1]

Adverse prognostic markers:[3][5]

• Prematurity / LBW / VLBW / ELBW.
• Neutropenia (ANC under 1,000) — bone marrow exhaustion; poor outcome.
• Persistent hypotension, acidosis (base deficit over 10), high lactate.
• Multi-organ failure.
• Gram-negative bacteraemia (higher mortality than GBS).
• Delay to antibiotic initiation — every hour of delay beyond the first hour increases mortality.

Mortality: 10-30% overall, 30-50% in VLBW; GBS meningitis approximately 10% mortality, Gram-negative meningitis 20-40% mortality.[5]

Neurological sequelae after neonatal meningitis: approximately 30-50% — hearing loss, cerebral palsy, cognitive impairment, epilepsy, hydrocephalus, blindness.[3]

Disposition: all suspected neonatal sepsis cases require admission to a neonatal unit (special care baby unit or NICU per acuity) for IV antibiotics and monitoring; severe cases to NICU for ventilation and inotropes. Step-down to SCBU when stable, afebrile, feeding, culture-negative at 48 h. Hearing screen before discharge if meningitis. [1]

Special Populations

• Premature / VLBW / ELBW — higher risk, blunted/atypical presentation, lower threshold to evaluate and treat, longer empirical courses, Candida and CoNS frequently implicated, monitor drug levels (gentamicin, vancomycin troughs), consider antifungal prophylaxis with fluconazole in extremely preterm (under 1000 g) on broad-spectrum antibiotics.
• Maternal GBS colonisation / chorioamnionitis / PROM over 18 h — well-appearing neonate: observe closely, use the EOS risk calculator to decide on empirical antibiotics. Ill-appearing neonate: full septic workup and empirical antibiotics.
• Outborn neonate (community delivery, especially in unhygienic settings) — higher risk of EOS and neonatal tetanus; ensure maternal tetanus toxoid status; consider tetanus immunoglobulin if cord stump contaminated.
• Surgical neonate (NEC, gastroschisis, diaphragmatic hernia) — mixed aerobic/anaerobic cover; Candida and resistant Gram-negatives common; prolonged antibiotic courses.
• Outbreak / NICU cluster — institute infection-control measures, screen contacts, identify the index case, perform environmental cultures, consider unit-specific empirical cover.
• Maternal HIV — routine neonatal sepsis approach; consider vertical transmission prophylaxis as per separate protocol; immunisation schedules may need adjustment. [1]

Evidence, Guidelines & Regional Differences

Key landmark guidelines and evidence:[3][6][1]

• AAP (Polin 2012, updated 2018-2019) — risk-factor-based EOS approach with the Kaiser Puopolo EOS risk calculator; culture and treat empirically when indicated; encourage antibiotic stewardship.
• NICE NG195 (UK, 2021) — intrapartum antibiotic and risk-factor-based algorithm; benzylpenicillin + gentamicin for EOS empirical cover; red-flag symptom checklist.
• CDC revised GBS prevention guidelines (Verani 2010) — universal vaginal-rectal GBS screening at 35-37 weeks, intrapartum antibiotic prophylaxis for GBS-positive or risk-factor-positive women; reduced early-onset GBS disease by approximately 80%.[8]
• ACOG Committee Opinion 797 (2020) — reaffirms universal screening, defines antibiotic choices (penicillin first, cefazolin second, clindamycin/vancomycin for allergic mothers).[7]
• Surviving Sepsis Campaign paediatric 2020 (Weiss et al.) — antibiotics within 1 h for septic shock, within 3 h for sepsis without shock; 10-20 mL/kg fluid boluses with reassessment; early inotropes.[1]
• Fleischmann-Struzek 2018; Fleischmann 2021 — global burden of neonatal sepsis: ~3 million cases / ~1 million neonatal deaths per year, with case-fatality 11-19% (high-income) and up to 25-50% (LMIC).[5][10]

Exam Pearls

[1] [1] [1] [1]

Exam application bank (NEET-PG / INICET)

One-line answer

Neonatal sepsis is a systemic inflammatory response to a documented or suspected infection in the first 28 days of life. It is the great mimic of neonatology: presentation is non-specific (temperature instability, poor feeding, lethargy, respiratory distress, apnoea). Divided into early-onset sepsis (EOS, within 72 hours or 7 days) — vertically acquired from the maternal genital tract, organisms Group B Streptococcus (GBS), E coli (K1 capsule), Listeria monocytogenes — and late-onset sepsis (LOS, after 72 hours or 7 days) — horizontally/nosocomially acquired, organisms coagulase-negative staphylococci (CoNS, S epidermidis), S aureus (incl MRSA), Klebsiella, E coli, Pseudomonas, Candida. Mortality 10 to 30% overall, higher in premature and LBW infants. Take a blood culture before antibiotics and start empirical IV antibiotics within 1 hour: UK benzylpenicillin + gentamicin (EOS) or fl

Worked stems (answer without another resource)

Stem 1 — Classic presentation. Map symptoms to mechanism; name the first investigation and first treatment step with dose/route if drug therapy is standard. [1]

Stem 2 — Unstable / complicated. List red flags that force immediate resuscitation, theatre, ICU, antidote, or reperfusion — and what you do in the first 15 minutes. [1]

Stem 3 — Atypical group. Elderly, pregnancy, child, or immunocompromised: how presentation and thresholds change. [1]

Stem 4 — Differential trap. Name the three closest mimics and one discriminator for each. [1]

Stem 5 — Disposition. Who goes home with safety-netting, who is admitted, who needs HDU/ICU/theatre, and what follow-up is mandatory. [1]

Rapid viva checklist

1. Definition + classification
2. Pathophysiology chain
3. Bedside signs / criteria
4. Score with exact components (if any)
5. Emergency bundle
6. Definitive therapy with doses
7. Complications of disease and of treatment
8. Special populations
9. Guideline/trial name if classic
10. Three exam traps

Coverage self-check

If you cannot answer any stem above from this page alone, re-read the matching section — the page is intended to be self-sufficient for final-prof and NEET-PG/INICET questions on Neonatal Sepsis.

References

1. [1]Glaser MA, Urbano M, Al-Rousan T, et al. Neonatal Sepsis: A Review of Pathophysiology and Current Management Strategies Adv Neonatal Care, 2021.PMID 32956076
2. [2]Raturi A, Sharma M, Goyal A, et al. Neonatal Sepsis: Aetiology, Pathophysiology, Diagnostic Advances and Management Strategies Clin Med Insights Pediatr, 2024.PMID 39371316
3. [3]Shane AL, Stoll BJ. Neonatal sepsis Lancet, 2017.PMID 28434651
4. [4]Strunk T, Currie A, Berrington JE, et al. Neonatal bacterial sepsis Lancet, 2024.PMID 38944044
5. [5]Fleischmann C, Konig F, Lissauer T, et al. Global incidence and mortality of neonatal sepsis: a systematic review and meta-analysis Arch Dis Child, 2021.PMID 33483376
6. [6]Polin RA; Committee on Fetus and Newborn. Management of neonates with suspected or proven early-onset bacterial sepsis Pediatrics, 2012.PMID 22547779
7. [7]American College of Obstetricians and Gynecologists (ACOG) Committee on Obstetric Practice. Prevention of Group B Streptococcal Early-Onset Disease in Newborns: ACOG Committee Opinion, Number 797 Obstet Gynecol, 2020.PMID 31977795
8. [8]Verani JR, McGee L, Schrag SJ; CDC. Prevention of perinatal group B streptococcal disease--revised guidelines from CDC, 2010 MMWR Recomm Rep, 2010.PMID 21088663
9. [9]Poggi C, Bianconi M, Perugi S, et al. Presepsin for the Diagnosis of Neonatal Early-Onset Sepsis: A Systematic Review and Meta-analysis JAMA Pediatr, 2022.PMID 35639395
10. [10]Fleischmann-Struzek C, Goldfarb DM, Schlattmann P, et al. The global burden of paediatric and neonatal sepsis: a systematic review Lancet Respir Med, 2018.PMID 29508706