Facts read from nccwebsite.org · last checked Nov 7, 2026
Infection is the second-largest system, 11 of the scored questions. The outline runs from normal neonatal immunity through a long list of organisms to sepsis, meningitis and infection control, and the hard questions are about whom to evaluate and when to stop.
Practice questions
60 questions written to the NNP-BC outline; each choice is explained once you pick.
Prevention: infection control and standard precautions.
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15 neonatal infection questions
0 / 15 answered15 questions
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Neonatal infectious diseases · 11 items
A 3-week-old former 33-week infant fed reconstituted powdered formula develops meningitis. MRI shows several brain abscesses with cystic change. The most likely organism is
Listeria meningitis comes from maternal food exposure in pregnancy and rarely produces multiple cystic abscesses.
Powdered formula is not sterile, and Cronobacter contaminating it causes meningitis in young and preterm infants with a high rate of abscess, infarction and cyst formation.
Klebsiella causes late-onset NICU sepsis and meningitis, but it is not the organism tied to contaminated powdered formula and cystic abscesses.
A septic, hypothermic 29-week infant in shock develops diffuse, cold, board-like hardening of the skin that cannot be pinched up, starting on the thighs and buttocks. The MOST likely diagnosis is
Cellulitis is warm, red, tender and localized; a cold, symmetric hardening spreading from the buttocks is not an infection of the skin itself.
Sclerema is diffuse, non-pitting, board-like hardening of the skin in a critically ill, cold, often septic preterm infant; it signals a poor prognosis and is treated through the underlying illness.
Edema in a sick preterm infant is common, but it pits and stays soft, whereas this skin cannot be pinched up at all.
A neonate has microphthalmia, cataracts, and a patent ductus arteriosus. The mother had a febrile illness with a rash in the first trimester and no prenatal care. Which congenital infection is most likely?
Congenital CMV causes microcephaly, periventricular calcifications and hearing loss, but not cataracts with a PDA.
Toxoplasmosis brings chorioretinitis, hydrocephalus and diffuse calcifications; the eye lesion is in the retina, not the lens.
Cataracts or microphthalmia with a PDA after a first-trimester maternal rash illness is the classic congenital rubella picture, often with sensorineural deafness.
A 24-week infant receiving IV lipid through a central catheter develops fever and thrombocytopenia. The blood culture grows yeast only on media supplemented with olive oil. The MOST likely organism is
Cryptococcus is an encapsulated yeast of immunocompromised hosts, rarely seen in neonates, and it does not need lipid to grow.
Candida causes most catheter fungemia in the NICU, but it grows readily on routine media without lipid supplements.
Malassezia is a lipid-dependent yeast that causes catheter fungemia in preterm infants on IV lipid and grows only when long-chain fatty acids such as olive oil are added to the medium.
A mother who ate unpasteurized cheese has fever in labor. Her 34-week infant develops early-onset sepsis with a granulomatous skin rash. The empiric regimen must include
Listeria, suggested by unpasteurized cheese, maternal fever and a granulomatous rash, is intrinsically resistant to cephalosporins, so ampicillin, usually with gentamicin, is essential.
Vancomycin targets resistant gram-positive cocci such as MRSA; it is not the drug relied on for Listeria.
Meropenem is a broad-spectrum reserve agent, not first-line empiric therapy, and using it here bypasses the standard ampicillin-based regimen.
A 26-week, 850-g infant in the NICU is exposed on day 10 to a visiting sibling with chickenpox. The mother had varicella as a child and is immune. The BEST action is to
Infants born before 28 weeks or at 1,000 g or less may not have received maternal IgG, which crosses mostly in the third trimester, so after exposure they get VariZIG whatever the mother's immunity.
Acyclovir treats or may back up prophylaxis when VariZIG is unavailable; it is not the standard first step for an exposed extremely preterm infant.
Varicella vaccine is a live vaccine licensed from 12 months and does not provide timely protection in a neonate.
A 12-day-old with meningitis has Citrobacter koseri growing from the CSF and is improving on cefepime and gentamicin. Which evaluation is MOST important?
Echocardiography is the follow-up for persistent Staphylococcus aureus bacteremia; it is not the key step in gram-negative meningitis.
EEG is ordered when seizures occur; it does not find the abscesses that make this organism dangerous.
Citrobacter koseri meningitis forms brain abscesses in a large share of neonates, so contrast neuroimaging is needed even with clinical improvement because an abscess changes duration and may need drainage.
On day 4, a well, afebrile term female develops crops of vesicles on a red base in linear streaks along the limbs. The CBC shows 20% eosinophils, and HSV PCR of the vesicles is negative. The most likely diagnosis is
Erythema toxicum also contains eosinophils, which tempts the choice, but its pustules are scattered on blotchy red skin, not arranged in linear streaks.
Vesicles along the lines of Blaschko with marked blood eosinophilia in a girl is the first stage of incontinentia pigmenti, an X-linked dominant disorder that needs eye and neurologic follow-up.
Bullous impetigo forms flaccid, crusting bullae with Staphylococcus aureus on culture, not linear vesicle streaks with eosinophilia.
A 900-g infant is born at 26 weeks after preterm labor with intra-amniotic infection; the mother received intrapartum antibiotics. Early-onset sepsis in this infant is MOST likely caused by
In very low birth weight infants E. coli has overtaken GBS as the main cause of early-onset sepsis, and intrapartum antibiotics further select for resistant gram-negative organisms.
Coagulase-negative staphylococci cause late-onset, catheter-related sepsis in the NICU, not infection acquired before birth.
Listeria is a classic early-onset pathogen, but it is now an uncommon cause of sepsis in very low birth weight infants.
An infant born to a mother treated for syphilis before pregnancy had a normal exam and a low RPR at birth. At 9 months the RPR is nonreactive, but the treponemal test (TP-PA) is still reactive. The BEST interpretation is
Response is judged by the nontreponemal titer; a falling-to-nonreactive RPR is the opposite of treatment failure.
Maternal treponemal IgG can persist in an uninfected infant until about 15 to 18 months, while passive RPR fades by about 6 months, so this pattern is expected.
Treponemal tests cannot separate passive antibody from infection in infancy; only a reactive treponemal test after 18 months suggests true infection.
A newborn has severe microcephaly with overlapping sutures and redundant scalp skin, subcortical calcifications, and arthrogryposis. The mother had a mild rash illness while living in Brazil in the first trimester. The MOST likely diagnosis is
CMV is the most common congenital infection and tempts the choice, but its calcifications are periventricular and it seldom causes joint contractures.
Toxoplasmosis gives diffuse calcifications, often with hydrocephalus and chorioretinitis, rather than a collapsed skull with arthrogryposis.
Zika causes a partially collapsed skull with overlapping sutures and redundant scalp, cortical–subcortical calcifications and joint contractures after a mild maternal rash in an endemic area.
A 3-week-old boy has fever and a red, swollen, tender area under the left jaw. The blood culture grows gram-positive cocci in chains. The most likely organism is
S. aureus also causes neonatal adenitis, but it grows in clusters on Gram stain, not chains.
Enterococcus does form chains, but it mainly causes line-related or urinary infection in the NICU, not submandibular cellulitis in a 3-week-old at home.
Cellulitis-adenitis of the face or submandibular area, mostly in boys aged 2 to 7 weeks, is a classic late-onset GBS presentation, often with bacteremia, so an LP is also needed.
A term infant with congenital toxoplasmosis (chorioretinitis and intracranial calcifications) starts pyrimethamine, sulfadiazine and folinic acid. The usual total duration of this therapy is
In the United States congenital toxoplasmosis is treated for about 12 months with pyrimethamine and sulfadiazine, plus folinic acid, with CBC monitoring for neutropenia.
Three months is far too short to prevent new chorioretinal lesions during infancy.
Six months is the valganciclovir course for symptomatic congenital CMV, the usual source of the mix-up.
A 12-day-old has fever, focal seizures and a few vesicles on the scalp. Empiric therapy must include
Fluconazole treats invasive candidiasis; vesicles with focal seizures in a 12-day-old point to a virus, not a yeast.
Fever, seizures and scalp vesicles in the second week mean neonatal HSV until proven otherwise, treated with high-dose IV acyclovir, 60 mg/kg/day, after HSV PCR testing.
Oral acyclovir is used only for suppression after a full IV course; it cannot reach adequate CNS levels for active disease.
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Sepsis and prevention traps
One approach for every gestational age. AAP's two 2018 clinical reports split early-onset sepsis risk: at 35 weeks or more you can use categorical criteria, the multivariate sepsis calculator or enhanced observation; below 35 weeks the circumstances of delivery set the risk, and a cesarean for a maternal reason without labor or rupture of membranes is low risk.
Starting antibiotics on a CBC or CRP. Those tests predict infection poorly in the first hours, and the same reports advise against letting them decide whether to start treatment. If the blood culture is still sterile at 36 to 48 hours in a well infant, antibiotics stop.
Hepatitis B in a small baby. With an HBsAg-positive mother, vaccine and hepatitis B immune globulin go in within 12 hours whatever the weight. Below 2,000 g that birth dose does not count toward the series, so the infant needs three more (ACIP 2018). The birth dose for infants of HBsAg-negative mothers became contested in December 2025, when ACIP and AAP diverged; we do not key questions on it.
RSV prevention from older sources. Current CDC and AAP guidance protects infants entering their first season with a long-acting monoclonal antibody, nirsevimab (50 mg under 5 kg, 100 mg at 5 kg or more) or clesrovimab, unless the mother received RSV vaccine at 32 to 36 weeks at least 14 days before birth. AAP's 2025 guidance no longer recommends palivizumab routinely.
Fungal prophylaxis for everyone. IDSA's 2016 candidiasis guideline reserves fluconazole prophylaxis for infants under 1,000 g in nurseries with high rates of invasive candidiasis.