True
The statement is TRUE: Oral candidiasis (thrush) in infants can occur through acquisition of Candida albicans during passage through the birth canal of a mother with vaginal candidiasis.
Evidence Supporting Vertical Transmission
The ESCMID guidelines explicitly recognize this transmission route, stating that "treatment of maternal vaginal candidiasis prior to delivery may prevent subsequent neonatal colonization" 1. This recommendation would not exist unless vertical transmission during delivery was an established mechanism.
Direct Molecular Evidence
Multiple research studies have confirmed mother-to-neonate transmission using sophisticated molecular typing:
DNA fingerprinting studies demonstrate that 76% of infants colonized with C. albicans by 1 week of age were born to C. albicans-colonized mothers 2. When molecular analysis was performed on 13 mother-infant pairs, 11 pairs (85%) showed identical DNA band patterns, confirming vertical transmission.
A case report using chromosomal karyotyping and restriction endonuclease analysis found that C. albicans isolates from a neonate's mouth, groin, and bloodstream were "visually indistinguishable" from the mother's vaginal isolate, providing direct molecular evidence of congenital transmission 3.
Another molecular study confirmed that C. albicans from a neonate's bloodstream and oral cavity shared a common genotype with the mother's vaginal isolate 4.
Transmission Dynamics
The epidemiology is well-established:
- At the end of pregnancy, 25-30% of women have C. albicans in vaginal secretions
- 70-85% of these colonized mothers transmit the yeast to their infants during delivery
- This results in approximately 22-24% of all infants acquiring C. albicans during birth 5
Important Caveats
While vertical transmission is a significant route, it's not the only mechanism:
- Among all infants colonized with C. albicans at any time point, only 41% acquired it through vertical transmission 2
- Horizontal transmission in the NICU also contributes substantially to colonization, particularly in very low birth weight infants
- The presence of white oral patches (clinical thrush) doesn't always correlate with C. albicans isolation—one recent study found no C. albicans in infants with clinical thrush 6
Clinical Implications
The recognition of vertical transmission has led to preventive strategies:
- Prepartal antifungal prophylaxis with intravaginal polyene or azole antimycotics at the end of pregnancy can reduce neonatal colonization 5
- This is particularly important for high-risk neonates (premature, very low birth weight) who are susceptible to invasive candidiasis
Bottom line: Vertical transmission during vaginal delivery is a well-documented and clinically significant route for neonatal oral candidiasis, though not the exclusive mechanism.