Clostridium difficile is recognized as an important cause of nosocomial diarrhoea in humans especially in association with administration of antibiotics. In pigs, C. difficile can cause neonatal... Show moreClostridium difficile is recognized as an important cause of nosocomial diarrhoea in humans especially in association with administration of antibiotics. In pigs, C. difficile can cause neonatal enteritis and can be isolated from faeces from both diseased and healthy animals. The presented prospective study describes how soon C. difficile can be isolated from newborn piglets after normal parturition and how C difficile spreads within a pig farm. Six sows, their farrowing crates and their litters at one farm were sampled until C. difficile was found in all piglets. Within 48 h after birth, all 71 piglets became positive for C. difficile (two piglets were already positive within 1 h post partum), all sows became positive within 11311 after parturition and the farrowing crates were found intermittently positive. C. difficile could also be detected in air samples and in samples of teats of the sows. All isolates belonged to PCR ribotype 078. Twenty-one C. difficile ribotype 078 isolates, found at the farm, were further analyzed by MLVA (multiple-locus variable-number tandem repeat analysis) and belonged to one clonal complex, except one isolate. To be sure that piglets were not born already infected with C. difficile ribotype 078, 38 caesarean derived piglets were sampled immediately after surgery. All piglets tested negative at delivery and stayed negative for C difficile ribotype 078 during the 21 days in which they were kept in sterile incubators. This study shows that C. difficile ribotype 078 spreads easily between sows, piglets and the environment. Vertical transmission of C. difficile ribotype 078 was not found and is very unlikely to occur. (C) 2010 Elsevier B.V. All rights reserved. Show less
Herpesviruses have evolved several effective strategies to counter the host immune response. Chief among these is inhibition of the host MHC class I antigen processing and presentation pathway,... Show moreHerpesviruses have evolved several effective strategies to counter the host immune response. Chief among these is inhibition of the host MHC class I antigen processing and presentation pathway, thereby reducing the presentation of virus-derived epitopes on the surface of the infected cell. This review summarizes the mechanisms used by herpesviruses to achieve this goal, including shut-down of MHC class I molecule synthesis, blockage of proteasome-mediated peptide generation and prevention of TAP-mediated peptide transport. Furthermore, herpesvirus proteins can retain MHC class I molecules in the endoplasmic reticulum, or direct their retrograde translocation from the endoplasmic reticulum or endocytosis from the plasma membrane, with subsequent degradation. The resulting down-regulation of cell surface MHC class! peptide complexes thwarts the ability of cytotoxic T lymphocytes to recognize and eliminate virus-infected cells. The subversion of the natural killer cell response by herpesvirus proteins and microRNAs is also discussed. (C) 2010 Elsevier B.V. All rights reserved. Show less
