Comparison of Agar Dilution and E-test for antimicrobial susceptibility testing of Campylobacter coli isolates recovered from 80 Ontario swine farms

The primary aim of this study was to evaluate the level of agreement of the E-test for in vitro antimicrobial susceptibility testing of Campylobacter coli using the agar dilution technique, which is the approved method. A convenience sample of 80 Ontario swine farms was chosen for this study; each farm was visited from January to June 2004. A total of 233 isolates of C. coli were tested for susceptibility to 10 antimicrobials by agar dilution and the E-test. Performance of the tests was evaluated using 7 quality control strains: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213, Campylobacter jejuni ATCC 33560, and Campylobacter coli ATCC 33559 for the E-test and E. coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and C. jejuni ATCC 33560 for the agar dilution test. Weighted Cohen's kappa and prevalence-adjusted bias-adjusted kappa (PABAK) tests were used for statistical analysis. The E-test and agar dilution test results had a strong agreement when resistance to streptomycin and tetracycline were evaluated (weighted kappa: 0.68 and 0.66, respectively). However, marked disagreement was detected when testing susceptibility to nalidixic acid and ampicillin (0.15 and 0.22, respectively). Almost perfect agreement was detected by PABAK when testing susceptibility to gentamicin (0.99). Agreement was found to be moderate for ciprofloxacin, azithromycin, clindamycin, erythromycin, and chloramphenicol. Although the level of agreement between the E-test and agar dilution depended on the antimicrobial being tested, the E-test always detected a lower proportion of resistant isolates compared to agar dilution.     

Functional Attributes of Proteins Withdrawn from Different Stages of a Commercial Ethanol Fuel/Distillers Dried Grains with Solubles Process Using a Wheat Feedstock

The functional attributes of proteins withdrawn from different stages of a commercial ethanol fuel/distillers dried grains with solubles (DDGS) process that used a wheat feedstock were investigated. Specifically, protein coproducts were examined postliquefaction (PL), postdistillation (PD), and postdrying (DDGS) and related to those from the native wheat feedstock (WF). Water hydration, oil holding, foaming, and emulsifying properties of all materials were assessed. The WF and the PL coproduct showed similar water hydration capacities (WHCs), ranging between 80 and 110%, whereas WHCs for the PD and DDGS coproducts were significantly higher (ranging between 264 and 356%). WHC for all products was found to be independent over the pH range of 2.00–10.00. A similar trend was found for the oil holding capacities, for which both WF and PL materials showed lower values (≈120%) than both the PD (203%) and DDGS (171%) materials. Foam capacity and stability for the WF were found to be 32.8 and 61.4%, respectively, whereas no coproducts were foam forming. Emulsion stability decreased from ≈45% for the WF to <10% in all other materials. Findings indicated that initial changes to the protein's functional attributes occurred in the PL stage of ethanol/DDGS processing.     

Thrombocytopenia in Newcastle disease: haematological evaluation and histological study of bone marrow

A Newcastle disease virus (NDV) isolated in Mexico and called Chimalhuacan strain was characterised by gene F restriction enzyme analysis and found to be a genotype II velogenic virus. Haematological evaluations and histological studies of bone marrow were conducted on chickens experimentally infected with the Chimalhuacan virus and on control chickens. Within 72 hours post infection (hpi), a 50% decrease in thrombocyte and monocyte counts and a complete cellular depletion in bone marrow islands were evident in the infected group. These findings suggest that the Chimalhuacan strain of NDV causes an early and severe damage of the haematopoietic cells including thrombocyte precursors, which might explain the marked thrombocytopenia detected in early stages of this disease.     

Evaluation of a questionnaire regarding nonphysical aspects of quality of life in sick and healthy dogs

OBJECTIVE: To evaluate the ability of a questionnaire regarding the nonphysical aspects of quality of life (QOL) to differentiate sick and healthy dogs. ANIMALS: 120 dogs. PROCEDURE: The questionnaire was administered by telephone to owners of 120 dogs with appointments at a veterinary teaching hospital. A QOL score was calculated for each dog on the basis of questions relevant to the dog during the 7 days before the interview. Scores were recorded as bar graphs, and linear regression was used to examine the effect of health status and other variables on QOL score. Certain questions were eliminated post hoc, on the basis of defined criteria, and the analyses were repeated. RESULTS: Scores were similar for sick (range, 670% to 93.8%) and healthy (range, 68.0% to 89.8%) dogs. Environment (suburban vs rural) and duration of ownership were significant explanatory variables and accounted for 10.5% of the variation in the QOL score. Eleven questions were eliminated post hoc. The scores derived from the 2 versions of the questionnaire were highly correlated (r = 0.92). CONCLUSIONS AND CLINICAL RELEVANCE: There was no evidence that the QOL questionnaire could differentiate healthy dogs from sick dogs; environmental and owner factors appeared to be more important.     

Morphology and growth characteristics of cultured Leptomonas ctenocephali from Ctenocephalides felis felis (Siphonaptera: Pulicidae) of dogs in Brazil

To confirm the taxonomic identification of a trypanosomatid found in the hindgut, rectum and Malpighian tubules of dog fleas captured in Belo Horizonte, Minas Gerais, Brazil, between April and November of 2005, 910 specimens of Ctenocephalides felis felis were removed from street dogs and dissected, and isolates from their digestive tracts were cultivated in NNN-alpha-MEM medium. Four different morphological forms were observed in culture: long, slender, twisted promastigotes with a long flagellum; short, stubby, non-twisted promastigotes; rounded amastigotes; and cyst-like bodies. Twisted and non-twisted promastigotes were frequently seen forming rosettes, and these two forms presented significant differences (P<0.01) in terms of their morphological characteristics. Unlike the promastigote forms observed throughout the culture period, rounded amastigotes were seen only in the lag phase, and the cyst-like bodies were only seen in the decline phase. The trypanosomatid DNA obtained from the culture was analyzed by the polymerase chain reaction (PCR) method and found to be negative for Leishmania infantum chagasi. Based on the growth pattern, morphological parameters and molecular analysis, the flagellates were confirmed to be Leptomonas ctenocephali. The significance of this infection for animals is also commented.     

Electron microscopic study of leucocytic infiltration of the mammary teat duct during infection with Staphylococcus aureus

Leucocytic response to Staphylococcus aureus infection was observed in the bovine mammary teat duct using transmission electron microscopy. Leucocytes migrating across the stratified squamous epithelium were observed in close association with areas colonised by cocci. Leucocytes gained access across the epithelium to the teat duct lumen by: passage as luminal cells desquamated; migration through degenerate cell cytoplasm; and penetration of cell junctions. The results provide evidence of marked leucocytic infiltration into ductal tissue which may participate in the cellular response to mastitis.     

Resistance mechanisms of the bovine udder: new implications for mastitis control at the teat end

Investigations on bovine teat-end defenses and their role in mastitis control were reviewed. Alteration of teat canal keratin by method of intramammary drug infusion through the teat canal influenced the number of new infections. At the beginning of the nonlactating period, 2 methods of administering antibiotic were studied: full insertion of treatment syringe cannulas into teat cisterns and expelling contents and partial insertion of cannulas into the distal 2 to 3 mm of teat canals and slowly infusing contents. Partial cannula insertion reduced new infections by 50% and is an easily adopted management tool to reduce prevalence of mastitis. Intramammary devices used during lactation and the nonlactating period increased leukocyte concentrations in mammary secretions. An abraded polyethylene coil device reduced clinical mastitis and increased milk yield. Staphylococci colonize teat canal keratin and lacteal secretions of dairy heifers as early as 9 months of age, leading to intramammary infection at time of calving and persisting into lactation. Subsequent somatic cell counts are associated with milk production losses. Previously, such infections were shown to be associated only with older, mature animals.     

Cochliomyia hominivorax myiasis in a colony of stray cats (Felis catus Linnaeus, 1758) in Rio de Janeiro, RJ

Cochliomyia hominivorax infestation in domestic cats of an urban colony in the city of Rio de Janeiro is described. The overall prevalence over the period 2001-2005 was 12.5%. Only adult cats were found infested and among these, most cases were observed in males (28%) (p < or = 0.05). The most frequently infested areas of the cats' bodies were the face and nape of the neck. Most lesions were found on the front part of the body of adult males (80%), suggesting that myiasis occur in consequence of competitive fighting wounds.