TY - CHAP M1 - Book, Section TI - Bacterial Infections A1 - Rapini, Ronald P. A2 - Barnhill, Raymond L. A2 - Crowson, A. Neil A2 - Magro, Cynthia M. A2 - Piepkorn, Michael W. A2 - Kutzner, Heinz A2 - Desman, Garrett T. PY - 2020 T2 - Barnhill's Dermatopathology, 4e AB - Definitive diagnosis of most bacterial diseases depends on specific identification of the pathogenic organisms. This must often be accomplished by appropriate cultures or molecular techniques because special bacterial stains frequently fail to detect sparse numbers of bacteria. Studies of infectious cellulitis show that even cultures yield organisms in less than 10% of cases. Cultures from actual biopsies have a higher yield than cultures originating from injected saline aspirates. Swab cultures from pustules, ulcers, or crusted lesions are suitable for only the most superficial infections, such as impetigo. An ideal method for deeper infections is to send half of the biopsy for culture and the other half for hematoxylin and eosin (H&E) and special stains. Before biopsy, excess antiseptic, such as chlorhexidine or povidone-iodine, which may inhibit the culture, should be wiped off the skin. Cultures are best performed on tissue that is rushed to the laboratory before it desiccates. It should be minced and added immediately to the culture medium. If there is a chance that a biopsy might dry during transport, the biopsy should be placed on sterile gauze soaked in normal saline (without preservatives such as benzyl alcohol). SN - PB - McGraw Hill Education CY - New York, NY Y2 - 2024/03/29 UR - dermatology.mhmedical.com/content.aspx?aid=1178393772 ER -