Synergistic hemolysis between ß-lysin-producing Staphylococcus species and Rothia nasimurium in primary cultures of clinical specimens obtained from dogs.

Nonhemolytic isolates of catalase-positive, Gram-positive cocci were observed that produced strong synergistic hemolysis with colonies of Staphylococcus pseudintermedius and Staphylococcus schleiferi subsp. coagulans in primary cultures of clinical specimens from dogs. The isolates appeared similar to nonhemolytic staphylococci but were not identified with conventional biochemical tests or commercial biochemical test kits. Partial 16S ribosomal RNA gene sequences from each of 9 tested isolates were nearly identical to that of Rothia nasimurium. The isolates produced positive Christie-Atkins-Munch-Peterson test reactions with Staphylococcus aureus (ATCC strain 25923) and Staphylococcus intermedius Hajek (ATCC strain 49052). The latter was identified in the current study as S. pseudintermedius. Rothia nasimurium appears to be a previously unreported commensal organism in dogs. Its potential significance as an opportunistic contributor to polymicrobial infections in dogs is not known.

A molecular technique for the detection and differentiation of Demodex mites on cats.

BACKGROUND: Demodex gatoi causes a pruritic dermatitis in cats. Diagnosis requires the demonstration of mites using superficial skin scrapings or faecal flotation, which can be insensitive. HYPOTHESIS/OBJECTIVES: The goal of this study was to develop a molecular method to diagnose D. gatoi infection in cats and distinguish these mites from Demodex cati. ANIMALS: Fifty-three shelter cats, 11 cats from a closed research colony and 12 privately owned cats were used. METHODS: Demodex gatoi and D. cati were obtained from scrapings of cat skin. The 16S rRNA DNA was amplified by PCR, sequenced and compared with available Demodex sequences. Hair and skin samples were also collected for microscopic examination and DNA isolation. RESULTS: DNA sequences were obtained from D. gatoi and D. cati. qPCR with D. gatoi specific primers and probe amplified DNA isolated from D. gatoi and not D. cati. Conversely, D. cati qPCR primers and probe amplified D. cati DNA and not D. gatoi. Five of the shelter cats were positive for D. gatoi. Two of these cats were pruritic, and the other three were in contact with these cats. Only one cat was positive for D. gatoi on skin scraping but was negative for D. gatoi or D. cati DNA. CONCLUSION: Results from this study show D. gatoi and D. cati to be distinct species. A novel qPCR test for the identification and differentiation of D. gatoi and D. cati was developed. Once optimized, this test could provide a valuable technique for the diagnosis of D. gatoi infection.

PCR amplification and DNA sequencing of Demodex injai from otic secretions of a dog.

BACKGROUND: The identification of Demodex mites from dogs is usually based on morphology and location. Mites with uncharacteristic features or from unusual locations, hosts or disease manifestations could represent new species not previously described; however, this is difficult to determine based on morphology alone. HYPOTHESIS/OBJECTIVES: The goal of this study was to identify and confirm Demodex injai in association with otitis externa in a dog using PCR amplification and DNA sequencing. METHODS: Otic samples were obtained from a beagle in which a long-bodied Demodex mite was identified. For comparison, Demodex mite samples were collected from a swab and scraping of the dorsal skin of a wire-haired fox terrier and an otic sample from a dog with generalized and otic demodicosis. To identify the Demodex mite, DNA was extracted, and 16S rRNA was amplified by PCR, sequenced and compared with Demodex sequences available in public databases and from separate samples morphologically diagnosed as D. injai and Demodex canis. RESULTS: PCR amplification of the long-bodied mite rRNA DNA obtained from otic samples was approximately 330 bp and was identical to that from the mite morphologically identified as D. injai obtained from the dorsal skin of a dog. Furthermore, the examined mite did not have any significant homology to any of the reported genes from Demodex spp. CONCLUSIONS: These results confirmed that the demodex mites in this case were D. injai.

Detection of human papillomavirus DNA in feline premalignant and invasive squamous cell carcinoma.

Squamous cell carcinoma (SCC) is the most common malignant cutaneous and oral neoplasm of cats. Papillomavirus (PV) DNA has been identified in a proportion of feline Bowenoid in situ carcinomas (BISCs), cutaneous SCCs and a single oral SCC, but its exact role in the pathogenesis remains unknown. In humans, it has been suggested that ultraviolet (UV) light and human PV (HPV) may act as cofactors in cutaneous SCC carcinogenesis. Little is known about the influence of UV light on PV prevalence in feline cutaneous lesions, including actinic keratosis (AK). Additionally, PV prevalence in noncutaneous feline lesions, including oral SCC, is largely not known. This study aimed to determine the presence of PV in 84 cats with premalignant and invasive SCC from cutaneous and noncutaneous sites using polymerase chain reaction and to investigate an association with UV light. Papillomaviral DNA was amplified from two of 12 cases of AK, seven of 22 BISCs, nine of 39 cutaneous SCCs and two of 35 non-cutaneous SCCs. Of the PV DNA sequenced, 50% was most similar to HPV of the genus Betapapillomavirus, while the other 50% was most similar to Felis domesticus PV type 2. Exposure to UV was not associated with an increase in PV for cutaneous SCC. The results of this study suggest that in the cat, HPV DNA may be detectible within a higher percentage of squamous lesions than previously demonstrated, UV exposure may not be a confounder for PV presence, and noncutaneous lesions may have a low prevalence of PV.

Molecular characterization of the L1 gene of papillomaviruses in epithelial lesions of cats and comparative analysis with corresponding gene sequences of human and feline papillomaviruses.

OBJECTIVE: To characterize the L1 gene of papillomaviruses detected in epithelial lesions of cats and to determine the relationship between those L1 gene nucleotide sequences and known L1 gene sequences of human and feline papillomaviruses. SAMPLE POPULATION: 10 tissue samples of epithelial lesions from 8 cats. PROCEDURES: DNA was extracted from tissue samples. Primers were designed to amplify the L1 gene of papillomaviruses. Amplicons of DNA were sequenced; nucleotide sequences were compared with known L1 gene nucleotide sequences of papillomaviruses and used for phylogenetic analysis. RESULTS: Tissue samples were obtained from lesions (diagnosed as dysplasia [n=1], squamous cell carcinoma in situ [3], or squamous cell carcinoma [6]) of the skin (9) and oral mucosa [1]. Two amplicons had 99% homology with the L1 gene nucleotide sequence of human papillomavirus type 38b subtype FA125. Another amplicon had 84% homology with the L1 gene nucleotide sequence of human papillomavirus type 80 and was considered to be a new type of papillomavirus. Phylogenetic tree analysis revealed that these 3 papillomaviruses were grouped into 2 clades that were not similar to the clades of Felis domesticus papillomavirus type 1 or F domesticus papillomavirus type 2 (FdPV2). The remaining 7 amplicons had 98% to 100% homology with the L1 gene nucleotide sequence of FdPV2. Phylogenetic tree analysis revealed that those 7 papillomaviruses were grouped nto a single clade with FdPV2. CONCLUSIONS AND CLINICAL RELEVANCE: Results support the likelihood of transmission of papillomaviruses between humans and cats.