Prevention of Aspergillosis in Bone Marrow

data suggest that the expression of different O antigens in E. coli or not these patients still were in a high efficiency particulate air (HEPA)–filtered environment. Indeed, in an LAF room, the patient from patient TB135 is not the result of plasmid-mediated serotype conversion, the common electrophoretic type, H antigen, eae genonot only breathes in air that is filtered through HEPA filters but also air that is forced in a laminar unidirectional pattern from one type, and patient origin of these organisms notwithstanding. wall to the opposite one. In addition, to live in an LAF room means to live in a room that is equipped with sleeved gloves Phillip I. Tarr, Carla R. Clausen, Thomas S. Whittam, hanging from a plastic wall and to be kept in a ‘‘sterile’’ environand Richard A. Wilson ment, which usually includes sterilization of every item entering Children’s Hospital and Regional Medical Center, Seattle, Washington the room, a sterile diet, skin disinfection, and so on. The reduction in the level of circulating spores seen in this environment, which References is likely to be responsible for the reduction in the incidence of 1. Bokete TN, Whittam TS, Wilson RA, et al. Genetic and phenotypic analysis aspergillosis [2, 3], is unlikely to be affected either by the laminar of Escherichia coli with enteropathogenic characteristics isolated from flow or by the isolation and sterilization procedures, but rather by Seattle children. J Infect Dis 1997;175:1382–9. the air filtration through the HEPA filters [3]. One can use HEPA 2. Keenleyside WJ, Whitfield C. Lateral transfer of rfb genes: a mobilizable filters without laminar flow and other isolation procedures and ColE1-type plasmid carries the rfbO:54 (O:54 antigen biosynthesis) gene still obtain a reduction in circulating spores (and consequently cluster from Salmonella enterica serovar Borreze. J Bacteriol 1995;177: aspergillosis) [4]. 5247–53. In conclusion, even if the multivariable analysis showed that 3. Bachmann BJ. Derivations and genotypes of some mutant derivatives of LAF rooms were associated with a reduced risk of early aspergilloEscherichia coli K-12. In: Neidhardt FC, ed. Escherichia coli and Salmonella—cellular and molecular biology. Washington, DC: ASM Press, sis, it is unlikely that this benefit resulted from the use of the LAF 1996:2460–88. room system as a whole, but rather by the air filtration through the HEPA filters. This point is extremely important because LAF Correspondence: Dr. Phillip I. Tarr, Dept. of Pediatrics, CH-24, Children’s rooms are uncomfortable for the patient and expensive for the Hospital and Regional Medical Center, Seattle, WA 98105-0371. health care system, as pointed out several years ago [5]. In my