Spatial Clustering of Escherichia coli with Reduced Susceptibility to Cefotaxime and Ciprofloxacin among Dairy Cattle Farms Relative to European Starling Night Roosts.

European starlings (Sturnus vulgaris) have been implicated in the dispersal of zoonotic enteric pathogens. However, their role in disseminating antimicrobial-resistant organisms through their home range has not been clearly established. The aim of this study was to determine whether starling night roosts served as foci for spreading organisms with reduced susceptibility to antimicrobials among dairy cattle farms. Bovine faecal pats were collected from 150 dairy farms in Ohio. Each farm was visited twice (in summer and fall) between 2007 and 2009. A total of 1490 samples (10 samples/farm over two visits) were tested for Escherichia coli with reduced susceptibility to cefotaxime and ciprofloxacin. Using a spatial scan statistic, focal scans were conducted to determine whether clusters of farms with a high prevalence of organisms with reduced susceptibility to cefotaxime and ciprofloxacin surrounded starling night roosts. Faecal pats 13.42% and 13.56% of samples carried Escherichia coli with reduced susceptibility to cefotaxime and ciprofloxacin, respectively. Statistically significant (P < 0.05) spatial clusters of faecal pats with high prevalence of Escherichia coli showing reduced susceptibility to cefotaxime and ciprofloxacin were identified around these night roosts. This finding suggests that the risk of carriage of organisms with reduced susceptibility to antimicrobials in cattle closer to starling night roosts was higher compared to cattle located on farms further from these sites. Starlings might have an important role in spreading antimicrobial-resistant E. coli to livestock environments, thus posing a threat to animal and public health.

Right Ventricular Epicardial Fibrosis in Mice With Sternal Segment Dislocation.

We report coincident sternal segment dislocation and focally extensive right ventricular epicardial fibrosis observed during routine histopathology evaluation of C57BL/6N mice as part of a high throughput phenotyping screen conducted between 4 and 16 weeks of age. This retrospective case series study was conducted to determine whether cardiac fibrosis was a pathological consequence of sternal segment dislocation. We identified sternal segment dislocation in 51 of the total 1103 mice (4.6%) analyzed at 16 weeks of age. Males were more frequently affected. In all cases but 2, the dislocation occurred at the fourth intersternebral joint. In 42 of the 51 cases (82.4%), the dislocation was encased by regenerative cartilaginous callus that protruded internally into the thoracic cavity (intrathoracic callus) and/or externally to the outer aspect of the sternum (extrathoracic callus). Displacement of dislocated ends of the sternum into the thoracic cavity was present in 19 of 51 cases (36.5%). Coincident minimal or mild right ventricular epicardial and subepicardial fibrosis was observed in 22 of the 51 cases (43%) but was not observed in any of the mice in the absence of sternal segment dislocation. Our data suggest that right ventricular fibrosis was likely caused by direct injury of the right ventricle by the dislocated ends of the sternum and/or by intrathoracic callus that develops post dislocation. Potential pathogenesis for the sternal and cardiac lesions and their implication for the interpretation of phenotypes in mouse models of cardiopulmonary and skeletal disease are discussed.

A longitudinal study of feed contamination by European starling excreta in Ohio dairy farms (2007-2008).

The objectives of this study were to understand the temporal pattern of contamination of cattle feed by starling excrement on dairy farms and to evaluate the temporal pattern in recovering Escherichia coli O157:H7 or Salmonella in relation to the absolute mass of excrement recovered. A longitudinal study was conducted on 15 dairy farms in Ohio from July 2007 to October 2008. One open-topped tray filled with bird feed was placed near a cattle feeding site; bird excrement from the tray was weighed monthly for 12 consecutive months. Linear regression models with a random intercept for farm were computed to examine the association between the absolute weight of excrement recovered each month or the farm-specific standard score for weight of excrement, and month or season. Exact logistic regression was used to determine whether an association between recovering E. coli O157:H7 or Salmonella was present and the amount of excrement recovered and season. A spatial scan statistic was used to test for evidence of space-time clustering of excrement, based on the standard score for the weight of the excrement, among our study farms. A total of 5 of 179 excrement samples (2.79%) were positive for E. coli O157:H7 and 2 (1.12%) were positive for Salmonella. A significantly higher level of contamination with excrement was observed during the winter. The odds of recovering a pathogen increased with the amount of excrement recovered and decreased if the excrement was collected in the winter. A spatio-temporal cluster of contamination with excrement was detected. These findings provide basic information for future quantitative microbial risk assessments concerning the role of starlings in spreading enteric pathogens on dairy farms.