Pseudomonas fluorescens contamination of a feline packed red blood cell unit and studies of canine units

Background: While screening programs have reduced the risk of infectious disease transmission by donors in human and veterinary blood banking, bacterial contamination of blood products has emerged as a major complication in human medicine. Objectives: To describe a Pseudomonas fluorescens (Pf)‐contaminated feline packed RBC (pRBC) unit and experimentally investigate Pf‐contaminated canine pRBCs. Methods: Canine pRBCs were inoculated with Pf‐rich pRBCs from the sentinel feline unit and stored at 4°C or 20°C for 72 hours. Aliquots from the pRBCs were serially evaluated by microscopy, culture, and a eubacterial 16S rRNA real‐time PCR assay. Results: One Pf‐contaminated feline unit turned black after 22 days of storage and was removed from the blood bank; a source was not found, and no other contaminated units were identified. Canine pRBCs spiked with 5 or 25 μL of the sentinel unit became culture‐ and/or 16S PCR‐positive at ≥8 hours at 20°C and 48 hours at 4°C and developed a color change at ≥24 hours. Sensitivity studies indicated that without incubation, inoculation of ≥100 μL Pf‐rich pRBCs was necessary for a positive 16S PCR test result. Conclusions: P. fluorescens grows in stored pRBCs slowly at 4°C and rapidly at 20°C. Screening of blood products for color change, estimating bacterial concentration with microscopy, and 16S PCR testing are simple and fast ways to detect bacteria in stored blood. Aseptic collection, temperature‐controlled storage, and regular visual monitoring of stored units is recommended. Discolored units should not be transfused, but examined for bacterial contamination or other blood product quality problems.     

A real-time PCR assay to detect the Panton Valentine Leukocidin toxin in staphylococci: screening Staphylococcus schleiferi subspecies coagulans strains from companion animals

Recent reports suggest that methicillin-resistant strains of Staphylococcus schleiferi subspecies coagulans are now commonly isolated from dogs. Given the association of a potentially mobile SCCmec type IV element with lysogenic phage-encoded Panton Valentine Leukocidin (PVL) toxin genes in community-acquired methicillin-resistant Staphylococcus aureus strains we hypothesized that methicillin-resistant S. schleiferi ssp. coagulans strains may also encode PVL toxin genes. Forty S. schleiferi ssp. coagulans strains isolated from companion animals were studied. Susceptibility to oxacillin was determined by broth microdilution and all isolates were screened by PCR for the presence of the mecA gene. SCCmec typing was performed on 14 isolates. A real-time PCR assay was developed for the detection of the PVL genes using a SmartCycler. Pulsed-field gel electrophoresis (PFGE) was performed to determine whether S. schleiferi ssp. coagulans strains were homogeneous. Twenty-eight of the 40 isolates (70%) were resistant to oxacillin and 26/28 possessed the mecA gene by PCR. SCCmec IV was identified in seven strains; the other seven isolates were not typable by this technique. All 40 strains were negative for the PVL toxin gene. PFGE showed a heterogeneous population and 13 different profiles were determined. In conclusion, this study showed that PVL toxin genes were not detected in a heterogeneous population of methicillin-resistant S. schleiferi ssp. coagulans strains isolated from companion animals.     

Optimization of a Staphylococcus aureus adhesion assay for equine corneocytes

Meticillin-resistant Staphylococcus aureus (MRSA) causes serious skin and soft-tissue infections of humans and animals. Multiple strains of MRSA have been characterized, and one in particular, designated as strain USA 500, causes infections predominantly of horses and the people who work with them. The purpose of this study was to optimize an assay which could subsequently be used to compare the relative avidity of different S. aureus strains for equine corneocytes. Corneocytes were collected from the perineal skin of 10 healthy horses onto adhesive discs. The discs were then incubated at 37°C with an S. aureus field strain at each of three concentrations [10(7), 10(8) and 10(9) colony forming units (CFU)/mL] and for each of three incubation periods (45, 90 and 180 min). After standardized rinsing and staining procedures, discs were examined at ×1,000 magnification and areas containing confluent corneocytes photographed. The percentage of surface area occupied by adherent bacteria was analysed using image processing and analysis software. Significant colour space image processing was required to distinguish bacteria from the ubiquitous melanin granules present within equine corneocytes. Objective and subjective methods were used to determine optimal conditions for specific adherence without introducing confounding factors. A bacterial concentration of 10(8) CFU/mL incubated with corneocytes for 45 min produced maximal bacterial adhesion with the least amount of interbacterial clumping. Future studies should utilize these conditions for optimal assay performance.     

Effects of 2 different medetomidine infusion rates on selected neurohormonal and metabolic parameters in dogs

The effects of 2 different 8-hour continuous rate infusions (CRIs) of medetomidine on epinephrine, norepinephrine, cortisol, glucose, and insulin levels were investigated in 6 healthy dogs. Each dog received both treatments and a control as follows: MED1 = 2 μg/kg bodyweight (BW) loading dose followed by 1 μg/kg BW per hour CRI; MED2 = 4 μg/kg BW loading dose followed by 2 μg/kg BW per hour CRI; and CONTROL = saline bolus followed by a saline CRI. Both infusion rates of medetomidine decreased norepinephrine levels throughout the infusion compared to CONTROL. While norepinephrine levels tended to be lower with the MED2 treatment compared to the MED1, this difference was not significant. No differences in epinephrine, cortisol, glucose, or insulin were documented among any of the treatments at any time point. At the low doses used in this study, both CRIs of medetomidine decreased norepinephrine levels over the 8-hour infusion period, while no effects were observed on epinephrine, cortisol, glucose, and insulin.     

Evaluating the Importance of Business Location Factors: The Influence of Facility Type

This study examines two important issues concerning the evaluation of business location factors. First, in contrast to many analyses that seek to determine the influence of a single factor or set of factors on site selection, this study aims to measure the relative importance of a wide range of factors. Second, it investigates the extent to which the perceived importance of a given location factor varies based on the type of facility in question. While there is a substantial amount of research devoted to identifying industry‐specific location factors, little is known about the influence that facility type has on the assessment of location criteria. Drawing on original survey data collected from real estate professionals in the U.S., we found significant differences in the mean ratings for more than half of the 39 location factors on the basis of facility type. In particular, “corporate/office” respondents were significantly more likely than “manufacturing” or “retail” respondents to assign higher ratings to “quality‐of‐life” location factors, such as crime rates, amenities, housing, and schools. We discuss the implications of these findings for future research on location theory.     

The Effect of Long Term Storage on Bacterial Soft Rot Resistance in Potato

Bacterial soft rot is a serious disease in potato (Solanum tuberosum L.), causing rapid tuber tissue maceration and, consequently, marketable yield loss. Soft rot bacteria, including Pectobacterium carotovorum subsp. carotovorum (Pbc), are favored by moist conditions, which are prevalent in large potato storage facilities. However, although most potatoes in North America are stored before use, there are no published surveys of soft rot resistance in cultivars exposed to long-term storage conditions. Thus, we tested 65 cultivars and 13 breeding lines for soft rot resistance after 6 months of storage. There was a significant effect of cultivar and production environment on soft rot resistance score. During 6 months of storage, tuber soft rot resistance in resistant clones did not change, while it changed in susceptible clones. The three most resistant cultivars to soft rot were Freedom Russet, Anett, and Alaska Red Eye.     

Relationships among milk urea-nitrogen, dietary parameters, and fecal nitrogen in commercial dairy herds

Our study objective was to determine the ability of milk urea-nitrogen concentrations ([MUN]) to predict fecal nitrogen concentrations ([Fecal N]) in commercial dairy herds. A total of 83 dairy herds were each visited 3 times within 48 h after a monthly herd milk test. For each farm visit, forages were sampled for nutrient analyses, which were entered into a computerized ration evaluator, and fecal samples were taken per rectum from each of 6 cows (2 early-, 2 mid-, and 2 late-lactation). Fecal samples were pooled, mixed, and analyzed for nitrogen content. Fecal nitrogen concentrations were compared with the routinely measured nutritional parameters from the ration evaluation, and the herd average [MUN] for the previous milk test date using mixed linear regression analyses. Total protein supplied in the ration was significantly positively associated with [Fecal N], but herd average [MUN] was not associated (P > 0.10) with [Fecal N].