Chapter 28: Infections – Expanded Coverage

🏥 Hospital infection control · Bacteriology lab · Antimicrobial principles · Botulism · Brucellosis · Escherichia coli · Haemophilus influenzae · Neonatal & pediatric infections
Based on Forfar & Arneil's Textbook of Pediatrics 7e. Interactive module: infection prevention, lab stewardship, rational antibiotics, specific bacterial diseases.

📖 Hospital infection control & key bacterial pathogens

🧼 Infection Control
Hand hygiene (ABHR), standard/contact/droplet/airborne precautions, PPE, isolation, environmental cleaning, antimicrobial stewardship, surveillance of HAI (CLABSI, CAUTI, VAP).
🔬 Bacteriology lab for pediatrician
Gram stain, culture (blood, CSF, urine, stool), susceptibility testing (MIC, disk diffusion), molecular (PCR, multiplex panels for meningitis/respiratory), biomarkers (CRP, PCT).
💊 Antimicrobial principles
Empiric vs directed therapy; PK/PD (time-dependent vs concentration-dependent); de-escalation; narrow-spectrum; duration; prevent resistance (MRSA, ESBL, VRE).
🦠 Key pathogens
Botulism (infant: honey, constipation, descending paralysis, antitoxin), Brucellosis (undulant fever, animal exposure, doxycycline+rifampin), E. coli (UTI, neonatal meningitis, STEC-HUS), Hib (epiglottitis, meningitis, bacteremia – vaccine-preventable).
⚠️ Critical alerts: Infant with hypotonia, poor feeding, history of honey → infant botulism (consult public health for BabyBIG). Brucella: prolonged fever, back pain, hepatosplenomegaly; requires serology and blood cultures (extended incubation). STEC O157:H7 → avoid antibiotics, monitor HUS.

🧼 Hospital Infection Control – Pediatric Focus

1
Standard precautions – Hand hygiene (alcohol-based hand rub before/after patient contact), use of gloves, gowns, masks for any procedure with splash risk, safe injection practices, environmental cleaning.
2
Transmission-based precautions – Contact (MRSA, VRE, rotavirus, RSV – gown + gloves); Droplet (meningococcus, influenza, pertussis – surgical mask); Airborne (TB, measles, varicella – N95, negative pressure room).
3
Prevention of device-associated infections – CLABSI (central line checklist, chlorhexidine dressing, remove unnecessary lines); CAUTI (avoid unnecessary catheterization); VAP (head of bed elevation, oral care).
4
Outbreak management & antimicrobial stewardship – Surveillance, cohorting, contact tracing. ASP: prior authorization, prospective audit, feedback, and stopping unnecessary antibiotics.
📌 Key metric: Hand hygiene compliance reduces HAI by 30-50%. Alcohol-based hand rub is preferred except for C. difficile and norovirus (soap and water).

💊 Antimicrobial therapy & the bacteriology laboratory

🔬
Lab tests for pediatrician – Gram stain (rapid orientation), culture & sensitivity (MIC, Kirby-Bauer), serology, antigen detection (urine for pneumococcus/Legionella), PCR panel (meningitis/encephalitis, respiratory viruses). Biomarkers: CRP (infection vs inflammation), procalcitonin (more specific for bacterial).
💊
Antimicrobial stewardship principles – Start empiric based on suspected pathogen and local epidemiology. Narrow as soon as possible. Duration: uncomplicated pneumonia 5-7 days, pyelonephritis 7-10 days, meningitis 10-21 days. Avoid unnecessary antiviral/antibiotic for viral URIs.
⚠️
Resistance concerns – MRSA (vancomycin, linezolid, clindamycin if susceptible), ESBL (carbapenems), VRE (linezolid, daptomycin). Use antibiogram for local guidance.

🦠 Deep dive: Botulism · Brucellosis · E. coli · Haemophilus influenzae

🐝 Botulism
Infant: Clostridium botulinum spores (honey, soil). Descending paralysis, constipation, bulbar weakness. Diagnosis: stool culture/mouse bioassay. Treatment: Human botulism immune globulin (BabyBIG), respiratory support.
🐑 Brucellosis (undulant fever)
Brucella melitensis (goats, unpasteurized dairy). Fever, arthralgia, hepatosplenomegaly. Lab: blood culture (extended incubation), serology (SAT, ELISA). Therapy: doxycycline + rifampin (or gentamicin) for 6 weeks.
🧫 Escherichia coli
Neonatal meningitis (K1 antigen); UTI (most common pathogen); STEC O157:H7 (bloody diarrhea → HUS). Avoid antibiotics in STEC; supportive care. UTI: TMP-SMX or cephalexin; pyelonephritis: ceftriaxone.
🩺 Haemophilus influenzae type b (Hib)
Invasive disease: epiglottitis, meningitis, septic arthritis, pneumonia. Prevented by conjugate vaccine (routine infant immunization). Suspect epiglottitis: airway emergency (do not examine throat). Empiric: ceftriaxone.

🧠 Reflex prompts – Hospital infection control & specific bacteria

👶 2-month-old, constipation, weak cry, poor feeding, ptosis. Honey ingestion. Most likely?
Infant botulism. Notify public health; administer BabyBIG (human antitoxin); monitor respiratory function.
🐐 Teen with fever, night sweats, back pain, history of consuming unpasteurized goat cheese. Likely?
Brucellosis. Blood cultures (hold >4 weeks), serology. Doxycycline + rifampin (or gentamicin).
💩 4-year-old with bloody diarrhea, abdominal cramps, no fever. Lab: E. coli O157:H7. What complication?
Hemolytic uremic syndrome (HUS). Avoid antibiotics; monitor platelets, Hb, creatinine.
🧫 Newborn with sepsis and meningitis. CSF gram-negative rods. Most likely E. coli serotype?
E. coli K1 (encapsulated). Empiric: cefotaxime/ceftriaxone + ampicillin (for Listeria).
😷 Child with stridor, drooling, toxic appearance, thumbprint sign on X-ray. Vaccine-preventable organism?
Haemophilus influenzae type b (Hib). Airway emergency, IV ceftriaxone, dexamethasone.
🧼 What is the most effective measure to prevent healthcare-associated infections?
Hand hygiene (alcohol-based hand rub or soap/water).
🔬 Which biomarker best differentiates bacterial from viral infection?
Procalcitonin (PCT) – high in bacterial, low in viral; CRP also elevated but less specific.
⚠️ A child with meningitis and petechial rash. CSF gram-negative diplococci. Prophylaxis for contacts?
Rifampin (or ciprofloxacin/ceftriaxone).
💊 What is the principle of de-escalation?
Start broad empiric antibiotics, then narrow based on culture/susceptibility to reduce resistance and toxicity.
🚫 Which isolation precautions for pulmonary tuberculosis?
Airborne precautions: N95 respirator, negative pressure room.