[Show abstract][Hide abstract] ABSTRACT: Molecular diagnostic tests have augmented the way in which veterinary practitioners approach the diagnosis of infectious disease. The technical bases of these tests are explained in addition to the general clinical applications for which they are most aptly suited, as individual assays are best discussed in the context of their respective diseases. In this article, an emphasis is placed on validation of molecular tests so that practitioners can be educated consumers of molecular diagnostics. The relationships between disease prevalence and positive and negative predictive values are discussed. Finally, examples of the pitfalls of multiplex polymerase chain reaction testing are illustrated.
No preview · Article · Nov 2013 · Veterinary Clinics of North America Small Animal Practice
[Show abstract][Hide abstract] ABSTRACT: Canine ocular onchocerciasis has a worldwide distribution and has been associated in Europe with Onchocerca lupi based on morphologic and molecular analysis. In the United States, canine ocular onchocerciasis is reportedly associated with Onchocerca lienalis. This association is based solely on histopathologic examination of ocular tissues. The purpose of this study was to use molecular analysis of formalin-fixed, paraffin-embedded canine ocular tissue to determine the genetic identity of Onchocerca associated with canine ocular onchocerciasis in the United States. PCR and DNA sequencing of the mitochondrial cytochrome oxidase I (cox1) and NADH hydrogenase 5 (nd5) genes demonstrated >99% similarity between the sequences obtained from canine ocular tissues previously diagnosed with onchocerciasis. The obtained sequences were most similar to O. lupi (>99% similarity). This report confirms for the first time that O. lupi is associated with canine ocular onchocerciasis in the United States, contrary to previously published reports.
No preview · Article · Dec 2012 · Veterinary Parasitology
[Show abstract][Hide abstract] ABSTRACT: We report the recovery of Escherichia coli or Klebsiella pneumoniae containing the extended-spectrum β-lactamase gene blaCTX-M from 24 of 1,495 (1.6%) swine fecal samples in 8 of 50 (16%) finishing barns located in 5 U.S. states. We did not detect
an association between antimicrobial use and recovery of blaCTX-M.
Preview · Article · Nov 2012 · Applied and Environmental Microbiology
[Show abstract][Hide abstract] ABSTRACT: To document whether presumptive bacterial translocation (PBT) occurs in horses with small intestinal strangulation (SIS).
Prospective clinical cohort study.
University tertiary care facility.
Thirty-six adult horses with SIS (clinical cases) and 10 adult horses without gastrointestinal disease (control cases).
Sterile collection and bacterial culture of samples from peripheral venous blood, mesenteric venous blood, mesenteric lymphatic tissue, and intestinal aspirates from horses with SIS and control horses without gastrointestinal disease.
Five of 36 (13.8%) horses with SIS had at least 1 sample yield a positive result. Shorter SIS bowel segments were more likely to yield a positive culture result. (P < 0.01). Two of 10 of control horses had positive culture results with different bacterial species identified compared to horses with SIS. Antimicrobial usage did not influence bacterial culture status (P = 0.31). There were no differences between culture-positive and culture-negative horses with SIS regarding admission, clinical, or clinicopathologic variables.
PBT occurs in normal horses and in horses with SIS. Bacterial genera differed between groups. A low incidence of PBT occurs in horses with SIS suggesting postoperative morbidity in some cases may be due to other factors.
[Show abstract][Hide abstract] ABSTRACT: A 5-year-old spayed female diabetic mixed-breed dog underwent phacoemulsification and intraocular lens implantation to correct bilateral hypermature cataracts. Two months postsurgery, the patient presented with ulcerative keratitis and multifocal stromal abscessation OD, which was controlled, but never resolved, with topical fluoroquinolone therapy. The patient re-presented 2 months later with a new, raised, white gritty corneal opacity associated with hyperemia, chemosis, and blepharospasm OD. Cytology of the right cornea revealed filamentous bacteria, suggestive of Actinomyces spp. Actinomyces bowdenii was subsequently isolated in pure culture and identified via 16s rDNA sequencing. Actinomyces bowdenii has never before been described as a cause of ocular infection. An immunosuppressed corneal environment likely contributed to this opportunistic Actinomycosis. The infection was not controlled with fluoroquinolone therapy, and the isolate, in vitro, was resistant to three fluoroquinolones (ciprofloxacin, ofloxacin, and levofloxacin), which also has not been previously reported for this species of Actinomyces. A superficial keratectomy with conjunctival graft was employed to successfully manage the infection.
No preview · Article · Nov 2012 · Veterinary Ophthalmology
[Show abstract][Hide abstract] ABSTRACT: bla(CTX-M) beta-lactamases confer resistance to critically important cephalosporin drugs. Recovered from both hospital- and community-acquired infections, bla(CTX-M) was first reported in U.S. livestock in 2010. It has been hypothesized that veterinary use of cephalosporins in livestock populations may lead to the dissemination of beta-lactamase-encoding genes. Therefore, our objectives were to estimate the frequency and distribution of coliform bacteria harboring bla(CTX-M) in the fecal flora of Ohio dairy cattle populations. In addition, we characterized the CTX-M alleles carried by the isolates, their plasmidic contexts, and the genetic diversity of the bacterial isolates themselves. We also evaluated the association between ceftiofur use and the likelihood of recovering cephalosporinase-producing bacteria. Thirty fresh fecal samples and owner-reported ceftiofur use data were collected from each of 25 Ohio dairy farms. Fecal samples (n = 747) yielded 70 bla(CTX-M)-positive Escherichia coli isolates from 5/25 herds, 715 bla(CMY-2) E. coli isolates from 25/25 herds, and 274 Salmonella spp. from 20/25 herds. The within-herd prevalence among bla(CTX-M)-positive herds ranged from 3.3 to 100% of samples. Multiple pulsed-field gel electrophoresis (PFGE) patterns, plasmid replicon types, and CTX-M genes were detected. Plasmids with CTX-M-1, -15, and -14 alleles were clonal by restriction fragment length polymorphism (RFLP) within herds, and specific plasmid incompatibility group markers were consistently associated with each bla(CTX-M) allele. PFGE of total bacterial DNA showed similar within-herd clustering, with the exception of one herd, which revealed at least 6 different PFGE signatures. We were unable to detect an association between owner-reported ceftiofur use and the probability of recovering E. coli carrying bla(CTX-M) or bla(CMY-2).
[Show abstract][Hide abstract] ABSTRACT: Norovirus (NoV) RNA was detected in the stools of 6 out 14 (42.8%) 8-12-week-old cats with enteritis from a feline shelter, in New York State. Upon sequence analysis of the complete capsid, the six NoVs were found to be identical, suggesting the spread of a unique NoV strain in the shelter. The full-length genomic sequence (7839 nt) of one feline NoV, CU081210E/2010/US, was determined. In the capsid protein VP1 region, the virus displayed the highest amino acid identity to animal genogroup IV genotype 2 (GIV.2) NoVs: lion/Pistoia-387/06/IT (97.9%) and dog/Bari-170/07/IT (90.4%). These findings document the discovery of a novel feline calicivirus, different from vesiviruses, and extend the spectrum of NoV host range. Epidemiological studies using feline NoV-specific diagnostic tools and experimental infection of cats are required to understand whether NoVs have a pathogenic role in this species.
[Show abstract][Hide abstract] ABSTRACT: Although canine ocular onchocerciasis has been well described as an emerging pathogen of dogs in Europe and North America over the past 20 years, there are no previous reports of feline ocular onchocerciasis. This report details the clinical, histopathologic, and molecular diagnosis of two domestic short hair cats residing in the United States infected with Onchocerca lupi causing episcleritis and orbital cellulitis. The results of this report suggest that O. lupi is a newly recognized disease of domestic cats.
No preview · Article · Sep 2011 · Veterinary Ophthalmology
[Show abstract][Hide abstract] ABSTRACT: A 5-year-old castrated male domestic longhair cat was presented with neurological signs consistent with a central vestibular lesion and left Horner's syndrome. Computed tomography images revealed hyperattenuating, moderately contrast-enhancing material within the left tympanic bulla, most consistent with left otitis media/interna. Marked neutrophilic pleocytosis was identified on cerebrospinal fluid analysis. Streptococcus equi subspecies zooepidemicus (SEZ) was isolated from the cerebrospinal fluid. Intracranial extension of otitis media/interna is relatively infrequent in small animals. There are no reports of otitis media/interna caused by SEZ in dogs or cats. This is the first report of otitis media/interna and presumptive secondary meningoencephalitis caused by SEZ in a cat.
[Show abstract][Hide abstract] ABSTRACT: Mycoplasmas are frequently isolated from many animal species. In domestic cats, mycoplasmas may be isolated from respiratory and ocular mucosae, but other sites are also occasionally colonized by these organisms. No cases of Mycoplasma species-associated neurologic disease have been reported in cats. We describe a case of Mycoplasma felis-associated meningoencephalitis in a 10-month-old domestic shorthair cat.
[Show abstract][Hide abstract] ABSTRACT: CTX-M extended-spectrum β-lactamases are enzymes produced by bacteria that are capable of inhibiting the antimicrobial effects of cephalosporin drugs. Recently, the first domestically acquired Salmonella in the United States expressing bla(CTX-M) was reported. This is a concern because expanded-spectrum cephalosporins are the treatment of choice for invasive Gram-negative infections, including salmonellosis in children. Because Salmonella transmission is primarily foodborne, there is also concern that resistant enteric bacteria from livestock can be transferred through the food supply chain to consumers. bla(CTX-M) has not been previously identified in bacterial isolates from food animal populations in the United States. We report the recovery of CTX-M-type extended-spectrum β-lactamases from fecal Escherichia coli of sick and healthy dairy cattle in Ohio. Four individual fecal samples yielded E. coli isolates representing three clonal strains that carried bla(CTX-M) on transferable plasmids. Two distinguishable plasmids were identified, each encoding bla(CTX-M-1) or bla(CTX-M-79). Transferrable bla(CTX-M) genes in bovine E. coli have the potential to serve as a reservoir of resistance for pathogens and may represent a public health concern.
No preview · Article · Dec 2010 · Foodborne Pathogens and Disease
[Show abstract][Hide abstract] ABSTRACT: The Clinical and Laboratory Standards Institute published in 2008 new interpretive criteria for the identification of methicillin resistance in staphylococci isolated from animals. The sensitivity of the 2008 interpretive criteria for mecA gene-positive Staphylococcus pseudintermedius, compared with the previous criteria of 2004, was investigated. Thirty clinical isolates of methicillin-resistant S. pseudintermedius from dogs were used. The presence of the mecA gene was determined by polymerase chain reaction. The minimum inhibitory concentration for oxacillin was determined by broth microdilution. The 2008 breakpoint of >or=4 microg/ml for methicillin resistance resulted in a diagnostic sensitivity of 73.3% (22/30). The 2004 breakpoint guideline of >or=0.5 microg/ml resulted in a diagnostic sensitivity of 97% (29/30). For oxacillin disk diffusion, the 2008 interpretive criterion of <or=10 mm for methicillin resistance resulted in a sensitivity of 70% (21/30). If intermediate isolates (11 or 12 mm) were considered resistant, the sensitivity was 93% (28/30). If intermediate isolates (11 or 12 mm) were considered resistant, the sensitivity was 93% (28/30). Application of the 2004 interpretive criterion of <or=17 mm resulted in a diagnostic sensitivity of 100% (30/30). For cefoxitin disk diffusion, the interpretive criterion of <or=21 mm for methicillin resistance (as used for Staphylococcus aureus) resulted in a diagnostic sensitivity of 6.7% (2/30). The interpretive criterion of <or=24 mm (as used for coagulase-negative staphylococci) resulted in a diagnostic sensitivity of 43.3% (13/30). With the use of 2008 interpretive criteria, all 3 tests produced what we consider to be an unacceptable level of false negative results. Our findings also suggest that cefoxitin disk diffusion is an inappropriate screening test for methicillin resistance of canine S. pseudintermedius.
Full-text · Article · Sep 2009 · Journal of veterinary diagnostic investigation: official publication of the American Association of Veterinary Laboratory Diagnosticians, Inc