title: Muramic and dipicolinic acids in atmospheric particulate matter as biomarkers of bacteria and bacterial spores.
abstract: Airborne bacteria are components of the atmospheric aerosol particles and can be responsible of allergic disease, regardless of their viability. In this paper, we report a method for the determination of total (viable and nonviable) bacterial content in airborne particles, using muramic and dipicolinic acids as biomarkers of bacteria and bacterial spores, respectively. The analytical procedure was optimized with bacteria and spores of Bacillus subtilis. After extraction and purification, the two biomarkers were analyzed by HPLC-ESI-MS/MS and their percentage was evaluated to be used as conversion factor. The present method for the determination of the total bacterial content was then applied to environmental samples, after a proper collection in an urban site. Thanks to the use of a low pressure impactor, capable of fractionating particles into the range of 0.03-10 μm, it was also possible to study the bacterial content in ultrafine, fine, and coarse particulate matter. The results from this study showed that muramic and dipicolinic acids can be determined together in one chromatographic run in reversed phase ion pair chromatography. Bacteria were more abundant than bacterial spores in the urban atmosphere, both showing a higher concentration in the coarse fraction of particles, although bacteria and bacterial spore amounts per unit mass of ultrafine particles were higher than in fine and coarse particles.
authors.affiliation: DIT, INAIL, Via di Fontana Candida 1, 00040, Monteporzio Catone, Rome, Italy. p.difilippo@inail.it.|Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy. p.difilippo@inail.it.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Di Filippo
authors.affiliation: DIT, INAIL, Via di Fontana Candida 1, 00040, Monteporzio Catone, Rome, Italy.|Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Donatella
authors.initials: D
authors.lastname: Pomata
authors.affiliation: DIT, INAIL, Via di Fontana Candida 1, 00040, Monteporzio Catone, Rome, Italy.|Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Carmela
authors.initials: C
authors.lastname: Riccardi
authors.affiliation: Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Buiarelli
authors.affiliation: Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Uccelletti
authors.affiliation: Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Zanni
mesh_terms: D000336:Aerosols / Q000032:analysis; D000391:Air Microbiology; D001272:Atmosphere / Q000032:analysis; D001412:Bacillus subtilis / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D057230:Limit of Detection; D009112:Muramic Acids / Q000032:analysis / Q000302:isolation & purification*; D052638:Particulate Matter / Q000032:analysis*; D010848:Picolinic Acids / Q000032:analysis / Q000302:isolation & purification*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013171:Spores, Bacterial / Q000302:isolation & purification*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D000336:Aerosols; D009112:Muramic Acids; D052638:Particulate Matter; D010848:Picolinic Acids; C004860:dipicolinic acid
keywords: Bacteria; Bacterial spores; Bioaerosol; Conversion factors; Dipicolinic acid; Muramic acid