Abstract 1612 Poster Session II, Sunday, 5/2 (poster 115)

Aim: Nosocomial infections are a major problem in neonatal intensive care units (NICUs). Pilot studies with DNA markers in the NICU indicate that the markers move by patterns consistent with contact transmission. We hypothesize that the movement of the DNA probe correlates well with the movement of bacteria and viruses via direct and indirect transmission pathways.

Methods: A DNA probe designed from regions of the cauliflower mosaic virus 35S promoter DNA was used as a surrogate marker of bacterial and viral transmission. Experiments simulating direct and indirect transmission were performed by placing a suspension of either Staphylococcus aureus / DNA probe or Primate Calivirus (PrCV) / DNA probe on a countertop. The inoculated area was rubbed with a dry paper towel, moist paper towel, or hand (gloved hand was used for the viral studies), and the paper towel or hand then was rubbed on an uninoculated area of the counter. The newly inoculated area was rubbed with a clean hand or new paper towel, which then was rubbed on a third area of the counter. Samples were collected from each of the surfaces and tested for S. aureus by plating on LB media, and for DNA probe and PrCV by polymerase chain reaction (PCR) or reverse transcription-PCR, respectively.

Results: 579 samples were collected and analyzed. The overall correlation coefficient (r2) between S. aureus and DNA probe was 0.83 (0.63 for dry paper towel, 0.94 for moist paper towel, and 0.91 for hand) and between PrCV and DNA probe was 0.99 (0.98 for dry paper towel, 0.99 for moist paper towel, and 1.00 for gloved hand).

Conclusions: The DNA probe is an excellent surrogate marker for direct and indirect transmission of bacteria and viruses. The DNA probe should be useful for studying pathogen transmission pathways in NICUs and for development of effective strategies for control of nosocomial infections.