BACTERIAL SURVIVAL ON RESPIRATORFILTERS ANDSURGICAL MASKS

The Centers for Disease Control and Prevention recently developed recommendations for respirators worn to minimize exposures to Mycobacterium tuberculosis.These recommendations include criteria for filters and facial fit, but do not address how respirators are worn or disposed of. Handling may increase the risk ofinfection if loaded organisms remain viable. Respirator filters were challenged with aerosols containing three bacteria: Mycobacterium abscessus, Staphylococcus epidermidis, and Bacillus subtilis subsp. niger. Elution and surface contact sampling were used to recover organisms from filters after loading and following 5 days storage at 85% RH. Almost all filters showed culturable organisms immediately after loading. After storage, filters showed the least culturability for M abscessus (20% of all filters) followed by S. epidermidis (61%), while B. subtilis remained highly culturable (98%). A slimilar trend was seen for the number of organisms recovered before and after storage (M abscessus demonstrated the least survival and B. subtilis the most).