Genetic characterization of hypervirulent Klebsiella pneumoniae responsible for acute death in captive marmosets.

Klebsiella pneumoniae is a Gram-negative bacterium implicated as the causative pathogen in several medical health issues with different strains causing different pathologies including pneumonia, bloodstream infections, meningitis and infections from wounds or surgery. In this study, four captive African marmosets housed in Thailand were found dead. Necropsy and histology revealed congestion of hearts, kidneys and adrenal glands. Twenty-four bacterial isolates were obtained from these four animals with all isolates yielding identical phenotypes indicative of K. pneumoniae based on classical identification schema. All the isolates show the susceptibility to amikacin, cephalexin, doxycycline, gentamicin, and enrofloxacin with intermediate susceptibility to amoxycillin/clavulanic acid. One isolate (20P167W) was chosen for genome analysis and determined to belong to sequence type 65 (ST65). The genome of 20P167W possessed multiple virulence genes including mrk gene cluster and iro and iuc gene cluster (salmochelin and aerobactin, respectively) as well as multiple antibiotic resistance genes including bla SHV-67, bla SHV-11, oqxA, oqxB, and fosA genes resembling those found in human isolates; this isolate has a close genetic relationship with isolates from humans in Ireland, but not from Thailand and California sea lions. Phylogenetic studies using SNP show that there was no relation between genetic and geographic distributions of all known strains typing ST65, suggesting that ST65 strains may spread worldwide through multiple international transmission events rather than by local expansions in humans and/or animals. We also predict that K. pneumoniae ST65 has an ability to acquire genetic mobile element from other bacteria, which would allow Klebsiella to become an even greater public health concern.

Ventral dermatitis in rowi (Apteryx rowi) caused by cutaneous capillariasis.

In 2013 there was an outbreak of crusting ventral dermatitis among a group of juvenile rowi (Apteryx rowi), a species of the endangered New Zealand kiwi, that were being raised on an off-shore island sanctuary. Biopsies taken at the time found nematodes migrating within the epidermis of affected skin but the specific identity and origin of the organisms was not established, and sporadic cases of similar skin disease continue to occur on the island. On examination of additional sections from the original skin biopsies, adult nematodes and eggs were identified, the histomorphology of which was consistent with Capillaria sensu lato. PCR was performed on DNA extracted from archived formalin-fixed, paraffin-embedded tissue blocks of skin from eight affected rowi, using primers targeting the 18S region of nuclear ribosomal DNA and the COI gene of mitochondrial DNA of capillarid nematodes. The 18S sequences from all rowi samples were identical and matched sequences from members of the genus Eucoleus. In contrast, two distinct capillarid COI sequences were obtained, in one case both from the same rowi skin biopsy. While there were no close matches, both COI sequences also aligned nearest to sequences identified as Eucoleus spp. It is considered unlikely that two different nematode species are involved in the rowi skin lesions and the possible amplification of a COI pseudogene or "numt" is discussed. A species-level identification of the capillarid nematodes causing skin disease in rowi was not obtained, however based on histological evaluation the infections include reproductively-active adult nematodes. This finding indicates the possibility of perpetuation of the skin disease in the absence of the original source, as well as raising potential for the transfer of infection from the island when the juvenile rowi are translocated to their new habitats.

Viral RNA load and histological changes in tissues following experimental infection with an arterivirus of possums (wobbly possum disease virus).

Tissues from Australian brushtail possums (Trichosurus vulpecula) that had been experimentally infected with wobbly possum disease (WPD) virus (WPDV) were examined to elucidate pathogenesis of WPDV infection. Mononuclear inflammatory cell infiltrates were present in livers, kidneys, salivary glands and brains of WPD-affected possums. Specific staining was detected by immunohistochemistry within macrophages in the livers and kidneys, and undefined cell types in the brains. The highest viral RNA load was found in macrophage-rich tissues. The detection of viral RNA in the salivary gland, serum, kidney, bladder and urine is compatible with transmission via close physical contact during encounters such as fighting or grooming, or by contact with an environment that has been contaminated with saliva or urine. Levels of viral RNA remained high in all tissues tested throughout the study, suggesting that on-going virus replication and evasion of the immune responses may be important in the pathogenesis of disease.

Generalized calcinosis cutis associated with probable leptospirosis in a dog.

A 6.5-year-old male German Shepherd acutely developed renal and hepatic disease. Serology revealed high concentrations of antibodies against Leptospira copenhageni, and a presumptive diagnosis of leptospirosis was made. The dog was successfully treated with antibiotics and supportive care over a 12-day period. Sixty-two days after the initial presentation, alopecia predominantly involving the dorsum and perineal areas developed. The skin lesions expanded over a 20-day period. Histology revealed generalized calcinosis cutis with follicular atrophy. An injection of 0.01 mg kg-1 dexamethasone suppressed serum cortisol concentrations. No treatment was given and lesions resolved over the following 30 days. This is the third case of generalized calcinosis cutis that has developed in an adult dog after severe systemic disease. Both previous cases developed calcinosis cutis in association with blastomycosis. To the authors' knowledge, this is the first report of generalized calcinosis cutis in an adult dog in association with a presumptive bacterial infection.