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Southern sea otters (SSO: Enhydra lutris nereis) are a federally-listed threatened subspecies found almost exclusively in California, USA. Despite their zoonotic potential and lack of host specificity, K. pneumoniae and Klebsiella spp. have largely unknown epizootiology in SSOs. Klebsiella pneumoniae is occasionally isolated at necropsy, but not from live SSOs. Hypermucoviscous (HMV) K. pneumoniae strains are confirmed pathogens of Pacific Basin pinnipeds, but have not been previously isolated from SSOs. We characterized the virulence profiles of K. pneumoniae isolates from necropsied SSOs, evaluated killing of marine mammal K. pneumoniae following in vitro exposure to California sea lion (CSL: Zalophanus californianus) whole blood and serum, and characterized lesion patterns associated with Klebsiella spp. infection in SSOs. Four of 15 SSO K. pneumoniae isolates were HMV and all were recovered from SSOs that stranded during 2005. Many K. pneumoniae infections were associated with moderate to severe pathology as a cause of death or sequela. All HMV infections were assessed as a primary cause of death or as a direct result of the primary cause of death. Klebsiella-infected SSOs exhibited bronchopneumonia, tracheobronchitis and/or pleuritis, enteritis, Profilicollis sp. acanthocephalan peritonitis, septic peritonitis, and septicemia. All SSO HMV isolates were capsular type K2, the serotype most associated with HMV infections in CSLs. Multiplex PCR revealed two distinct virulence gene profiles within HMV isolates and two within non-HMV isolates. In vitro experiments investigating CSL whole blood and serum killing of K. pneumoniae suggest that HMV isolates are more resistant to serum killing than non-HMV isolates.

Hypermucoviscous K. pneumoniae (HMV) are emergent zoonotic pathogens associated with increased invasiveness and pathogenicity in terrestrial and marine mammals. In this study, HMV and non-HMV isolates recovered from stranded pinnipeds were used to investigate: 1) their persistence in sea and fresh water microcosms at 10 and 20°C, 2) their capacity to form biofilms, and 3) the biocide efficacy of four disinfectants on their planktonic and biofilm phenotypes. Results indicated that although HMV isolates were significantly more mucoviscous, non-HMV isolates displayed significantly greater capacity to form biofilms (p < 0.05). Additionally, non-HMV isolates persisted in greater numbers in both sea- and freshwater, particularly at 20°C. These two phenomena could be associated with the greater growth observed for non-HMV isolates in in-vitro growth-curve assays (p < 0.05). Similar susceptibility to disinfectants was detected in HMV and non-HMV isolates when exposed for 24 h; however, the minimal biofilm disinfectant eradication concentration for HMV isolates was significantly higher than that for non-HMV when exposed to disinfectants for 0.5 h. This information should be taken into consideration when developing biosecurity protocols in facilities holding marine mammals in captivity.

Little is known regarding the degree of genotypic relatedness between Streptococcus canis isolates from dogs and cats. The purpose of this study was to determine whether correlations existed between the genotypes of canine and feline S. canis isolates as determined using pulsed-field gel electrophoresis (PFGE) and different clinical manifestations of disease. Eighty-two isolates of S. canis were examined that had been collected from dogs and cats presenting to the University of California, Davis Veterinary Medical Teaching Hospital (VMTH) between 1998 and 2005. Associated clinical manifestations included sepsis, otitis, pyometra, skin infections, necrotizing fasciitis, respiratory disease, and urinary tract infections. In addition, 9 feline isolates from a southern California shelter that experienced an outbreak of S. canis infection manifesting as necrotizing fasciitis and death were examined. Bacterial isolates were characterized by PFGE analysis using the restriction enzyme SmaI. The relationships between banding patterns were analyzed using gel analysis software combined with visual interpretation. The feline shelter isolates of S. canis were 99% similar in bacterial PFGE profile. The remainder of samples had less than 80% similarity in PFGE banding patterns. The relatedness of the PFGE profile in the feline shelter isolates suggested a clonal origin. In the isolates from the VMTH population, there was no relationship between specific disease manifestations and PFGE profile. PFGE typing does not appear to be useful for identifying isolates associated with specific disease presentations; however may be more useful to identify outbreaks of S. canis infections or to detect clonal populations in outbreaks.

The aim of this study was to determine if antimicrobial drug use increases resistance of commensal gastrointensinal Escherichia coli of wild northern elephant seals ( Mirounga angustirostris ) treated in rehabilitation, and, if so, identify the risk factors involved. Minimum inhibitory concentration (MIC) levels of twelve antimicrobial drugs were determined for 289 E. coli isolates from 99 seals sampled at admission and 277 isolates obtained at release from rehabilitation using broth microdilution. Prevalence of E. coli antimicrobial resistance, MIC 50 , MIC 90 , and clustering of MIC values were determined for seals and the data were analyzed using Fisher's exact test, ordinal logistic regression and negative binomial regression. At release from rehabilitation 77.8% of the seals had antimicrobial resistant E. coli compared to 38.4% of the seals at admission. The MIC 90 for amoxicillin-clavulanic acid, chloramphenicol, enrofloxacin, ticarcillin-clavulanic acid, and trimethoprim-saulfamethoxazole were at levels considered to be sensitive at admission but they increased to levels of resistance at release. E. coli were grouped into four clusters by their MIC values, with increasing levels of resistance going from Cluster 1 to 4. A primary risk factor associated with the probability of a seal having E. coli in Clusters 3 and 4 was time in rehabilitation, regardless of whether the animal received treatment with antimicrobial drugs, suggesting nosocomial infection. The results of this study provide evidence that increased levels of hygiene and appropriate use of antimicrobial therapy might be important in the rehabilitation of wild animals to prevent rise in the prevalence of antimicrobial resistant bacteria.

Preliminary analysis of a partial (30% coverage) genome sequence of Rhodococcus equi has revealed a number of important features. The most notable was the extent of the homology of genes identified with those of Mycobacterium tuberculosis. The similarities in the proportion of genes devoted to fatty acid degradation and to lipid biosynthesis was a striking but not surprising finding given the relatedness of these organisms and their success as intracellular pathogens. The rapid recent improvement in understanding of virulence in M. tuberculosis and other pathogenic mycobacteria has identified a large number of genes of putative or proven importance in virulence, homologs of many of which were also identified in R. equi. Although R. equi appears to have currently unique genes, and has important differences, its similarity to M. tuberculosis supports the need to understand the basis of virulence in this organism. The partial genome sequence will be a resource for workers interested in R. equi until such time as a full genome sequence has been characterized.

Since 2002, vegetative valvular endocarditis (VVE), septicemia and meningoencephalitis have contributed to an Unusual Mortality Event (UME) of northern sea otters in southcentral Alaska. Streptococcal organisms were commonly isolated from vegetative lesions and organs from these sea otters. Bartonella infection has also been associated with bacteremia and VVE in terrestrial mammals, but little is known regarding its pathogenic significance in marine mammals. Our study evaluated whether Streptococcus bovis/equinus (SB/E) and Bartonella infections were associated with UME-related disease characterized by VVE and septicemia in Alaskan sea otter carcasses recovered 2004-2008. These bacteria were also evaluated in southern sea otters in California. Streptococcus bovis/equinus were cultured from 45% (23/51) of northern sea otter heart valves, and biochemical testing and sequencing identified these isolates as Streptococcus infantarius subsp. coli. One-third of sea otter hearts were co-infected with Bartonella spp. Our analysis demonstrated that SB/E was strongly associated with UME-related disease in northern sea otters (P

Rhodococcal pneumonia is an important, life threatening disease of foals and immunosuppressed humans. Increased knowledge of the mechanisms of protective immunity are required in order to develop an effective immunoprophylaxis strategy for horses and immunotherapeutic regiments for people. Both humoral and cellular components of the immune system may be involved in immune clearnace of R. equi . The susceptibility of foals less than 4–6 months of age is postulated to reflect waning maternal antibody, and passive transfer of hyperimmune plasma can provide protection on endemic farms. However, effective clearance is likely to require appropriate cellular responses, including the secretion of cytokines. In murine models, both CD4 + and CD8 + T lymphocytes can reduce bacterial counts in the lung. CD4 + cells appear to be both required and sufficient, and IFN-gamma is a primary mediator. Clearance appears to be a type 1 immune response while type 2 responses may lead to a failure to clear and lesion development. It remains to be determined how the cellular immunity experiments reported in mice relate to horses and humans. Likewise, the role of specific R. equi antigens in protective immunity has not been determined.