Which genus is vancomycin resistant and associated with septicemia in neonates?

Which genus is vancomycin resistant and associated with septicemia in neonates?

• A. Staphylococcus
• B. Leuconostoc
• C. Streptococcus
• D. Enterococcus

Answer: (B)

Vancomycin targets the cell wall by binding to the D-Ala-D-Ala terminus of peptidoglycan precursors, but some organisms carry a different terminal configuration (D-Ala-D-Lac) that vancomycin cannot bind effectively. Leuconostoc species have this intrinsic alteration, making them vancomycin resistant. In neonates, especially in NICU patients with invasive devices or parenteral nutrition, Leuconostoc is a recognized cause of septicemia. Lab identification can be tricky because these organisms may resemble streptococci, which can lead to ineffective vancomycin therapy if not correctly identified. While vancomycin resistance can occur with Enterococcus in hospital settings, the classic association with vancomycin-resistant septicemia in neonates points to Leuconostoc. Staphylococcus and Streptococcus are not characteristically vancomycin-resistant in this neonatal context.

Vancomycin targets the cell wall by binding to the D-Ala-D-Ala terminus of peptidoglycan precursors, but some organisms carry a different terminal configuration (D-Ala-D-Lac) that vancomycin cannot bind effectively. Leuconostoc species have this intrinsic alteration, making them vancomycin resistant. In neonates, especially in NICU patients with invasive devices or parenteral nutrition, Leuconostoc is a recognized cause of septicemia. Lab identification can be tricky because these organisms may resemble streptococci, which can lead to ineffective vancomycin therapy if not correctly identified. While vancomycin resistance can occur with Enterococcus in hospital settings, the classic association with vancomycin-resistant septicemia in neonates points to Leuconostoc. Staphylococcus and Streptococcus are not characteristically vancomycin-resistant in this neonatal context.