Quarantine for contaminated pathogens in transplantable human tumors or infections in tumor bearing mice.

To quarantine human tumor samples for transplantation into immune deficient mice or tumor xenograft lines established and introduced from other institutions, we performed isolated implantation and passaging of tumors in a vinyl isolator, and microbiological examinations of sentinel mice kept together with tumor bearing mice. We examined 105 pairs of sentinel mice used to quarantine 907 tumors, and found six cases of contamination or infection with Staphylococcus aureus, 20 cases with Pseudomonas aeruginosa and one case with mouse hepatitis virus (MHV). It was, however, possible that Mycoplasma pulmonis contamination was overlooked because the microbe had been isolated from tumors passaged after quarantine, even though the results of the quarantine of these tumors showed no sign of pathogens. Direct culture of tumors for the microbe was recommended to improve the quarantine system.