VapB type 8 plasmids in Rhodococcus equi isolated from the small intestine of pigs and comparison of selective culture media.

UNLABELLED: The virulence-plasmid profile of Rhodococcus equi strains isolated from Suidae and humans is similar. Recent evidence suggests that the consumption of pork products contaminated with faeces might be a potential source of R. equi infections in humans, mainly to patients with rhodococcosis without history of contact with pigs or pig farms. This study investigated the virulence-associated genes (vapA and vapB) and plasmid profiles of R. equi among the 150 samples of small intestinal content obtained from slaughtered pigs. In addition, all samples were subjected to microbiological culture in conventional sheep blood agar and CAZ-NB, TCP and TVP selective media. A total of 40 (26·7%) of the samples recovered R. equi, with two samples recovering isolates harbouring the VapB type 8 plasmid. Among the 150 pigs sampled herein, CAZ-NB was considered the best selective medium for the isolation of R. equi from faeces. Our results provide evidence that the contamination of slaughtered pig carcasses with pathogenic R. equi might occur through faeces, representing a public health concern. Furthermore, this study is the first description of R. equi strains carrying the VapB plasmid in the gut of pigs. SIGNIFICANCE AND IMPACT OF THE STUDY: Intermediately virulent (VapB) is a common plasmid-type harboured by R. equi isolated from pigs and humans with AIDS. Curiously, humans with rhodococcosis usually have no history of contact with pigs or pig farms. Virulence-plasmid profile of 40 R. equi isolated among 150 small intestine content samples from pigs revelled two carrying isolates with the VapB type-8 plasmids. Moreover, comparison of three selective culture media shows that CAZ-NB was the best. Our results provide evidence that contamination of slaughtered pig carcasses with pathogenic R. equi might occur through faeces, representing a public health concern. Furthermore, R. equi carrying VapB type-8 plasmids types are described for the first time in the gut of the pig.

A synchrotron computed tomography dataset for validation of longitudinal tensile failure models based on fibre break and cluster development.

We performed in-situ tensile tests on two carbon fibre/epoxy composites with continuous scanning using synchrotron computed tomography (CT). Both composites were cross-ply laminates, and two specimens were tested for each composite. The voxel size was sufficiently small to recognize individual fibres and fibre breaks. For each test, 16-19 volumes were reconstructed, cropped down to the 0° plies and analysed to track fibre break and cluster development. This dataset provides the last CT volume before failure for each of the four specimens as well as the individual fibre break locations in all reconstructed volumes. These data are then plotted against predictions from six state-of-the-art strength models. The target is that these data become a benchmark for the development of new models, inspiring researchers to set up refined experiments and develop improved models.

Population Dynamics of the Swallowtail Butterfly Battus polystictus polystictus (Butler) (Lepidoptera: Papilionidae) with Notes on Its Natural History.

Battus polystictus (Butler) is a butterfly from the Neotropical region, occurring in the Atlantic Forest and Pampa biomes. It is commonly found in forest fragments surrounded by meadow formations, subjected to marked seasonal changes. Here, we report the population dynamics of B. polystictus at a high latitude environment and provide notes on its natural history. Population parameters were estimated on a 12-month mark-recapture program and the seasonality of resources investigated by exhaustive mapping of host-plants and flowers. The number of butterflies per day was not stable during the year, ranging from zero (winter) to 22 (summer); the sex ratio was always male biased (3M:1F). The age structure was not constant, with an increase of older individuals toward summer. The population density was positively correlated with temperature, relative humidity, and day length. The residence time was lower for males, while the vagility was lower for females; the increment of resources at forest edges seems to increase the likelihood of occurrence of both sexes. The results shown here suggest that South Brazilian populations of B. polystictus have high ecological demands for spring and summer conditions, avoiding winter in diapause.