In vitro and in vivo evaluation of a potentiated miconazole aural solution in chronic Malassezia otitis externa in dogs.

This study assessed the in vitro and in vivo activity of an ear solution containing a third-generation chelating agent (Tricide) as an antimicrobial potentiator for miconazole in chronic Malassezia otitis. Thirty-one ears from 20 dogs were enrolled in the study. Fungal culture, minimum inhibitory concentration (MIC), and minimum fungicidal concentration (MFC) testing of miconazole with and without Tricide were performed on all ears.

Identification, antimicrobial resistance profiles, and virulence of members from the family Enterobacteriaceae from the feces of yellow-headed blackbirds (Xanthocephalus xanthocephalus) in North Dakota.

Public pressure to reduce or eliminate antimicrobials as ingredients of feed for poultry and other agricultural animals is mounting, primarily due to the fear of multidrug-resistant bacteria in clinical infections in both animals and humans. Exploration of the occurrence of antibiotic resistance in the gut flora of wildlife avian flocks that presumptively do not receive antimicrobials will determine the rate of resistance in a naïve population. Fecal samples collected from a healthy population of the yellow-headed blackbirds (YHB) (Xanthocephalus xanthocephalus) in North Dakota were cultured to determine what genera and species of gram-negative facultative anaerobic bacteria these wild birds carry in their intestinal flora and to evaluate the antimicrobial susceptibility profiles.

In vitro efficacy of a buffered chelating solution as an antimicrobial potentiator for antifungal drugs against fungal pathogens obtained from horses with mycotic keratitis.

Objective: To determine whether a novel third-generation chelating agent (8 mM disodium EDTA dehydrate and 20 mM 2-amino-2-hydroxymethyl-1, 3-propanediol) would act as an antimicrobial potentiator to enhance in vitro activity of antifungal medications against fungal isolates obtained from horses with mycotic keratitis.

Sample Population: Fungal isolates (3 Aspergillus isolates, 5 Fusarium isolates, 1 Penicillium isolate, 1 Cladosporium isolate, and 1 Curvularia isolate) obtained from horses with mycotic keratitis and 2 quality-control strains obtained from the American Type Culture Collection (ATCC; Candida albicans ATCC 90028 and Paecilomyces variotii ATCC 36257).

Procedure: Minimum inhibitory concentrations (MICs) against fungal isolates for 4 antifungal drugs (miconazole, ketoconazole, itraconazole, and natamycin) were compared with MICs against fungal isolates for the combinations of each of the 4 antifungal drugs and the chelating agent.

Development and evaluation of an experimental model of cutaneous columnaris disease in koi Cyprinus carpio.

A reproducible, experimental model of columnaris disease was developed to study the pathogenesis of cutaneous disease associated with Flavobacterium columnare infection in koi (Cyprinus carpio). In experimental infections, lesions were usually restricted to skin and fins; gill necrosis was not a consistent finding. Cytologic and histopathologic examinations provided a presumptive diagnosis of columnaris disease.

Comparison of several challenge models for studies in avian colibacillosis.

In previous studies, the embryo lethality assay (ELA) discriminated between virulent and avirulent avian Escherichia coli isolates, and also proved to be highly correlated with mortality and morbidity results of the intravenous (IV) challenge model. In the current study, the same 20 avian E. coli isolates were used in subcutaneous (subQ) and intratracheal (IT) chicken challenge models in order to determine whether the results from the prior ELA challenges and/or the IV challenge model correlate with these models.

In vitro effect of a buffered chelating agent and neomycin or oxytetracycline on bacteria associated with diseases of fish.

The antimicrobial agents used to treat bacterial fish diseases are archaic, and their uses may result in the emergence of drug-resistant bacterial strains. This study evaluated the in vitro antimicrobial activity of combinations of Tricide and neomycin or oxytetracycline on common disease-causing bacteria of fish and its possible use as an alternative treatment of these diseases. Tricide solutions containing of 8 mM United States Pharmacopeia (USP) disodium ethylenediaminetetraacetate dehydrate (chelator) and 20 mM USP 2-amino-2-hydroxymethyl-1,3-propanediol (buffer) potentate the antimicrobial action of neomycin and oxytetracycline when reacted in vitro with Aeromonas hydrophila, Streptococcus iniae, Pseudomonas aeruginosa, and Staphylococcus aureus.

Use of potentiated antibiotics in wound management.

Prevention or resolution of microbial colonization of wounds is critical to rapid and uneventful healing. The use and misuse of antimicrobial agents continues to support the evolution of multidrug resistant organisms that can cause severe or life-threatening infections. Chelating agents have been shown to potentiate the effects of antimicrobial compounds.

Characterizing avian Escherichia coli isolates with multiplex polymerase chain reaction.

Colibacillosis caused by Escherichia coli infections account for significant morbidity and mortality in the poultry industry. Yet, despite the importance of colibacillosis, much about the virulence mechanisms employed by avian E. coli remains unknown.

Comparison of the intravenous chicken challenge method with the embryo lethality assay for studies in avian colibacillosis.

In previous studies, the embryo lethality assay (ELA) was able to discriminate between virulent and avirulent avian Escherichia coli isolates and to predict percent mortality of the embryos resulting from an isolate based on three traits. The abilities to resist host complement, presence of Colicin V activity, and presence of the increased serum survival gene cluster (iss), were used together in a logistic regression analysis to predict the percentage of embryo deaths resulting from each of 20 avian E. coli isolates used in the ELA.

Prediction of chicken embryo lethality with the avian Escherichia coli traits complement resistance, colicin V production, and presence of the increased serum survival gene cluster (iss).

Differentiating between virulent and avirulent avian Escherichia coli isolates continues to be a problem for poultry diagnostic laboratories and the study of colibacillosis in poultry. The ability of a laboratory to conduct one simple test that correlates with virulence would simplify studies in these areas; however, previous studies have not enabled researchers to establish such a test. In this study, the occurrence of certain phenotypic and genotypic traits purported to contribute to avian E.

Development of resistant bacteria isolated from dogs with otitis externa or urinary tract infections after exposure to enrofloxacin in vitro.

Minimum inhibitory concentrations for enrofloxacin were determined for 63 bacterial isolates from dogs with otitis externa or urinary tract infections. Development of resistant mutants was determined after exposing the isolates to enrofloxacin in vitro for up to five serial passages. Results indicated that Pseudomonas aeruginosa and Enterococcus spp isolates exposed to enrofloxacin developed resistance rapidly, whereas Klebsiella, Proteus, and Streptococcus spp were less likely to develop resistance.

Virulence factors associated with Escherichia coli present in a commercially produced competitive exclusion product.

In this study, we assessed the pathogenic potential of Escherichia coli associated with a commercial competitive exclusion (CE) product by examining the phenotypic characteristics associated with E. coli virulent for humans and domestic animals. Most E.

In vitro evaluation of the antimicrobial effect of commercially available mastitis medications combined with EDTA-Tris on bacteria that cause mastitis in cattle.

A study was conducted to evaluate the antimicrobial activity of selected commercial mastitis medications with and without EDTA-Tris by comparing minimum inhibitory concentrations and minimum bactericidal concentrations in vitro. Solutions containing 5 mM EDTA/50 mM Tris potentiated the antimicrobial action of seven commercially available mastitis medications when reacted in vitro with Staphylococcus aureus, Streptococcus uberis, and Pseudomonas aeruginosa. Lesser potentiation was observed for Escherichia coli, whereas no potentiation was observed for Klebsiella pneumoniae.

Complement resistance, as determined by viable count and flow cytometric methods, and its association with the presence of iss and the virulence of avian Escherichia coli.

Previous work in our labs has shown that avian Escherichia coli virulence is correlated with resistance to complement. Also, our studies have revealed that the presence of the increased serum survival gene (iss), known to contribute to the complement resistance and virulence of mammalian E. coli, may predict the virulent nature of an avian E.

Location of increased serum survival gene and selected virulence traits on a conjugative R plasmid in an avian Escherichia coli isolate.

Avian colibacillosis is a costly disease for the poultry industry. The mechanisms of virulence employed by the etiologic agent of this disease remain ill defined. However, accumulated evidence suggests that complement resistance and the presence of the increased serum survival gene (iss) in an avian Escherichia coli isolate may be indicative of its ability to cause disease.