title: Identification by real-time PCR with SYBR Green of Leishmania spp. and Serratia marcescens in canine 'sterile' cutaneous nodular lesions.
abstract: BACKGROUND
  Noninfectious, non-neoplastic, nodular to diffuse, so-called 'sterile' granulomatous/pyogranulomatous skin lesions (SGPSLs) are infrequently identified in dogs and may represent a diagnostic challenge. Their correct identification is based on history, histopathology and absence of intralesional foreign bodies and micro-organisms.
  
  
  OBJECTIVE
  The aim of this study was to investigate the presence of Leishmania spp., Mycobacterium spp., Serratia marcescens and Nocardia spp. by real-time PCR in canine nodular skin lesions histologically diagnosed as putatively sterile.
  
  
  METHODS
  Formalin-fixed skin biopsies were collected from 40 dogs. All samples were associated with an SGPSL diagnosis characterized by multifocal, nodular to diffuse, periadnexal and perifollicular pyogranulomas/granulomas. Neither micro-organisms nor foreign bodies were detected with haematoxylin and eosin staining, under polarized light. Further analyses included periodic acid Schiff, Ziehl-Neelsen, Fite Faraco, Giemsa and Gram histochemical stains; anti-Bacillus Calmette-Guérin (BCG) and Leishmania spp. immunohistochemistry; and real-time PCR analysis for Leishmania spp., Mycobacterium spp., S. marcescens and Nocardia spp.
  
  
  RESULTS
  Special stains and BCG/immunohistochemistry were negative in all samples. Real-time PCR was positive for Leishmania spp. in four of 40 biopsies and for S. marcescens in two of 40 samples. Real-time PCR for Mycobacterium spp. and Nocardia spp. was negative. No correlation between real-time PCR positivity and a specific histological pattern was identified.
  
  
  CONCLUSIONS
  Leishmania spp. have been previously identified as possible agents of certain SGPSLs, while the involvement of S. marcescens has not been investigated previously. According to our findings, Serratia spp. should be included in the list of agents possibly associated with a subgroup of granulomatous/pyogranulomatous skin lesions in dogs.
authors.affiliation: Department of Veterinary Sciences and Public Health DIPAV, Faculty of Veterinary Medicine, University of Milan, via Celoria 10, 20133, Milan, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Cornegliani
authors.affiliation: Ambulatorio Veterinario Associato, c.so Traiano 99/d, 10135, Turin, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Corona
authors.affiliation: Ambulatorio Veterinario Associato, c.so Traiano 99/d, 10135, Turin, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Vercelli
authors.affiliation: Department of Veterinary Sciences and Public Health DIPAV, Faculty of Veterinary Medicine, University of Milan, via Celoria 10, 20133, Milan, Italy.
authors.forename: Paola
authors.initials: P
authors.lastname: Roccabianca
mesh_terms: D000818:Animals; D052160:Benzothiazoles; D001706:Biopsy / Q000662:veterinary; D003959:Diamines; D004283:Dog Diseases / Q000175:diagnosis* / Q000382:microbiology / Q000469:parasitology / Q000473:pathology; D004285:Dogs; D005456:Fluorescent Dyes; D007891:Leishmania; D007896:Leishmaniasis / Q000175:diagnosis / Q000473:pathology / Q000662:veterinary*; D009161:Mycobacterium; D009615:Nocardia; D009930:Organic Chemicals; D011804:Quinolines; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary*; D016868:Serratia Infections / Q000175:diagnosis / Q000662:veterinary*; D012706:Serratia marcescens; D012867:Skin / Q000382:microbiology / Q000469:parasitology / Q000473:pathology*
chemical_list: D052160:Benzothiazoles; D003959:Diamines; D005456:Fluorescent Dyes; D009930:Organic Chemicals; D011804:Quinolines; C098022:SYBR Green I