Scientific Publications by FDA Staff

J Allergy Clin Immunol 2005 Dec;116(6):1296-1300

Bacterial 16S ribosomal DNA in house dust mite cultures.

Valerio CR, Murray P, Arlian LG, Slater JE

Slater JE, Ctr Biol Evaluat & Res, US FDA, HFM 422,1401 Rockville Pike, Rockville, MD 20852 USA Ctr Biol Evaluat & Res, US FDA, Rockville, MD 20852 USA Natl Inst Hlth, Bethesda, MD USA Wright State Univ, Dayton, OH 45435 USA

BACKGROUND: Allergen extracts prepared from Dermatophagoides farinae contain significantly more endotoxin than Dermatophagoides pteronyssinus extracts, and extracts from both mite extracts contain more endotoxin than pollen extracts. Attempts to culture bacteria from mite cultures have failed to establish the sources of the endotoxin. OBJECTIVE: To determine the bacterial sources of endotoxin in mite extracts. METHODS: Live mites of both species were obtained from 2 sources, DNA was extracted from the mites, and DNA encoding bacterial 16S ribosomal RNA was amplified by using specific primers. The amount of bacterial DNA in each mite DNA sample was determined by quantitative PCR using an internal standard, and sequence homologies were determined from amplifications performed by using a high-fidelity DNA polymerase. RESULTS: DNA from D farinae appeared to contain between 11-fold and 24-fold more 16S ribosomal gene copies than the genomic DNA from D pteronyssinus (P