Genetic Structure of Mycobacterium avium subsp. paratuberculosis Population in Cattle Herds in Quebec as Revealed by Using a Combination of Multilocus Genomic Analyses

Mycobacterium avium subsp. paratuberculosis is the etiological agent of paratuberculosis, a granulomatous enteritis affecting a wide range of domestic and wild ruminants worldwide. A variety of molecular typing tools are used to distinguish M. avium subsp. paratuberculosis strains, contributing to a better understanding of M. avium subsp. paratuberculosis epidemiology. In the present study, PCR-based typing methods, including mycobacterial interspersed repetitive units/variable-number tandem repeats (MIRU-VNTR) and small sequence repeats (SSR) in addition to IS1311 PCR-restriction enzyme analysis (PCR-REA), were used to investigate the genetic heterogeneity of 200 M. avium subsp. paratuberculosis strains from dairy herds located in the province of Quebec, Canada. The majority of strains were of the “cattle type,” or type II, although 3 strains were of the “bison type.” A total of 38 genotypes, including a novel one, were identified using a combination of 17 genetic markers, which generated a Simpson''s index of genetic diversity of 0.876. Additional analyses revealed no differences in genetic diversity between environmental and individual strains. Of note, a spatial and spatiotemporal cluster was evidenced regarding the distribution of one of the most common genotypes. The population had an overall homogeneous genetic structure, although a few strains stemmed out of the consensus cluster, including the bison-type strains. The genetic structure of M. avium subsp. paratuberculosis populations within most herds suggested intraherd dissemination and microevolution, although evidence of interherd contamination was also revealed. The level of genetic diversity obtained by combining MIRU-VNTR and SSR markers shows a promising avenue for molecular epidemiology investigations of M. avium subsp. paratuberculosis transmission patterns.     

Mupirocin Resistance in Isolates of Staphylococcus spp. from Nasal Swabs in a Tertiary Hospital in France

Mupirocin is a topical antibiotic largely used to eradicate staphylococcal nasal carriage. Here, we investigated the prevalence of mupirocin-resistant Staphylococcus aureus and coagulase-negative staphylococcal isolates recovered from patients in different wards in a hospital (Lyon, France), which were determined both phenotypically with an Epsilometer test (Etest) and genetically by PCR for mupA and mupB.     

Poly(D,L-Lactide) Nanocapsules Containing Non-Steroidal Anti-Inflammatory Drugs: Gastrointestinal Tolerance Following Intravenous and Oral Administration

Pharmaceutical Research -     

A case of retinoblastoma, associated with histiocytosis-X and mosaicism of a deleted D-group chromosome (13q14→q31)

A previously unpublished association of retinoblastoma and histiocytosis-X is described in a girl. In addition, chromosome analysis revealed a mosaicism of normal and abnormal mitoses. A deleted D-group chromosome (13q14-q31) was present.     

Compartmental ordering of cholinergic innervation in the mediodorsal nucleus of the thalamus in human brain

The cholinergic innervation of the mediodorsal (MD) nucleus of the thalamus was visualized immunohistochemically in human brain postmortem, using an antibody against human choline acetyltransferase (ChAT). The ChAT staining of the MD nucleus was more intense than in the surrounding thalamic nuclei but weaker than that of the striatum. No ChAT-positive cell bodies were detected. The ChAT-positive neuropil was unevenly distributed, with patches of dense immunoreactivity contrasting with a weaker surrounding matrix. In adjoining sections stained for ChAT immunoreactivity and for acetylcholinesterase (AChE) activity, the zones enriched in ChAT-immunostained neuropil corresponded to AChE-rich regions. The three-dimensional reconstruction of the richest zone in AChE/ChAT activity evidenced a cylindrical organization throughout the rostrocaudal axis of the MD nucleus. Counts of ChAT-positive varicosities confirmed an inhomogeneous distribution; the density of varicosities was 30% higher in ChAT-rich regions than in surrounding matrix. These findings suggest that the activity of intrinsic neurons within the nucleus may be differentially regulated by cholinergic systems.