Antibiotic exposure and bacterial resistance in human and veterinary medicine: a problem-based learning topic for Master's students.

This report describes a problem-based learning activity concerning antibiotic exposure and bacterial resistance in human and veterinary medicine. In addition, learning outcomes and satisfaction of students were recorded by the supervisors of the activity. The students all participated actively in the group work and considered that the small size of the group facilitated interpersonal communication. They believed that working in an interdisciplinary group helped them learn better than if they were following specific courses. They also reported that their mid-term meeting with one of the supervisors was a catalyst for the initiation of a real work group. Concerning the evaluation of the activity itself, the supervisors considered that the group provided a relevant analysis of the issue. These characteristics should encourage teachers to test this method of learning certain aspects of microbiology and infectious diseases with their students.

Integration of microbiology and infectious disease teaching courses in an interdisciplinary training programme (Master level) centred on the 'One world, one health' WHO concept.

This report describes the integration of the microbiology and infectious diseases teaching courses in an international Master's level interdisciplinary programme based on the 'One world, one health' WHO concept, and reports the students and teachers' evaluation related to their feelings of about this innovative programme. The integration was evaluated by recording the positioning of these two topics in the five teaching units constituting the programme, and by identifying their contribution in the interactions between the different teaching units. The satisfaction of students was assessed by a quantitative survey, whereas the feelings of students and teachers were assessed by interviews. The study demonstrated that microbiology and infectious diseases were widely involved in interactions between the teaching units, constituting a kind of cement for the programme. The students assigned a mean score of 3.7 to the topics dealing with microbiology and infectious diseases. According to the qualitative data, students and teachers considered that the interdisciplinary approach provided new insights but reported problems of communication, probably inherent to the multiculturalism of the class.

Efficacy of an oral live vaccine for veterinary use against pseudotuberculosis.

Pseudotuberculosis, an infection caused by the ubiquitous enteropathogenic bacterium Yersinia pseudotuberculosis, is a recurrent veterinary problem in livestock and zoo animals. The only vaccine currently available in zoos is Pseudovac (a mixture of killed strains of various serotypes), but its efficacy is not well established. We show here that Pseudovac does not protect guinea pigs against a severe Y. pseudotuberculosis infection. We thus evaluated the possibility of using a live attenuated Y. pseudotuberculosis strain (IP32680) as an oral vaccine against animal pseudotuberculosis. We report that IP32680 is avirulent for guinea pigs and induces a strong IgG response against various serotypes of Y. pseudotuberculosis. One and two oral inoculations of IP32680 provided 50% and 83% protection, respectively against a severe infection with a highly pathogenic strain. The avirulent Y. pseudotuberculosis IP32680 is therefore much more protective than Pseudovac and may represent a valuable oral vaccine against pseudotuberculosis in zoo animals.

Human susceptibility and resistance to Norwalk virus infection.

Infectious diseases have influenced population genetics and the evolution of the structure of the human genome in part by selecting for host susceptibility alleles that modify pathogenesis. Norovirus infection is associated with approximately 90% of epidemic non-bacterial acute gastroenteritis worldwide. Here, we show that resistance to Norwalk virus infection is multifactorial. Using a human challenge model, we showed that 29% of our study population was homozygous recessive for the alpha(1,2)fucosyltransferase gene (FUT2) in the ABH histo-blood group family and did not express the H type-1 oligosaccharide ligand required for Norwalk virus binding. The FUT2 susceptibility allele was fully penetrant against Norwalk virus infection as none of these individuals developed an infection after challenge, regardless of dose. Of the susceptible population that encoded a functional FUT2 gene, a portion was resistant to infection, suggesting that a memory immune response or some other unidentified factor also affords protection from Norwalk virus infection.

Norwalk virus binds to histo-blood group antigens present on gastroduodenal epithelial cells of secretor individuals.

BACKGROUND & AIMS: Norwalk Virus (NV) is a member of the Caliciviridae family, which causes acute epidemic gastroenteritis in humans of all ages and its cellular receptors have not yet been characterized. Another calicivirus, Rabbit Hemorrhagic Disease Virus, attaches to H type 2 histo-blood group oligosaccharide present on rabbit epithelial cells. Our aim was to test if, by analogy, recombinant NV-like particles (rNV VLPs) use carbohydrates present on human gastroduodenal epithelial cells as ligands. METHODS: Attachment of rNV VLPs was tested on tissue sections of the gastroduodenal junction and on saliva from individuals of known ABO, Lewis, and secretor phenotypes. It was also tested on human Caco-2 cells and on animal cell lines transfected with glycosyltransferases complementary DNA (cDNA). Competition experiments were performed with synthetic oligosaccharides and anticarbohydrate antibodies. Internalization was monitored by confocal microscopy. RESULTS: Attachment of rNV VLPs to surface epithelial cells of the gastroduodenal junction as well as to saliva was detected, yet only from secretor donors. It was abolished by alpha1,2fucosidase treatment, and by competition with the H types 1 and 3 trisaccharides or with anti-H type 1 and anti-H types (3/4) antibodies. Transfection of CHO and TS/A cells with an alpha1,2fucosyltransferase cDNA allowed attachment of VLPs. These transfectants as well as differentiated Caco-2 cells expressing H type 1 structures internalized the bound particles. CONCLUSIONS: rNV VLPs use H type 1 and/or H types (3/4) as ligands on gastroduodenal epithelial cells of secretor individuals.