Can the association of athymic mice (Han:NMRI-nu) with Staphylococcus sciuri prevent infection with Staphylococcus aureus? Experiences from a field study.

An attempt was made to prevent the introduction of Staphylococcus aureus into a newly established colony of Han:NMRI-nu mice by means of preassociation with the rodent-specific Staphylococcus sciuri. Despite the successful colonization of the mice with S. sciuri the establishment of S. aureus into the colony was not impeded, and abscesses were observed with an increasing frequency until the end of the study. Random samples revealed the phage pattern 3A/3C/55/71 or very similar ones. A caretaker was identified as a possible vector of transmission, since he was found to be colonized with this S. aureus phage type previous to the outbreak. Finally, the later occurrence of Citrobacter freundii and Pseudomonas aeruginosa serovar P10 in the colony led to the decision to give it up after 21 months of existence.