High resolution melting PCR to differentiate Mycobacterium avium subsp. paratuberculosis"cattle type" and "sheep type".

In this study, we describe a novel HRM-PCR assay that clearly differentiates the two main types of Mycobacterium avium subsp. paratuberculosis (cattle and sheep) based on the polymorphic variation of a previously described tandem repeat. This modern genotyping technique has several advantages over alternative methods, including cost, ease of use and rapidity.

Isolation and detection of Mycobacterium avium subsp. paratuberculosis (MAP) from cattle in Ireland using both traditional culture and molecular based methods.

BACKGROUND: Mycobacterium avium subsp. paratuberculosis (MAP) causes a chronic gastroenteritis affecting many species. Johne's disease is one of the most widespread and economically important disease of ruminants. Since 1992 and the opening of the European market, the exposure and the transmission of MAP in cattle herds considerably increased. Improvements in diagnostic strategies for Ireland and elsewhere are urgently required. In total, 290 cattle from seven Irish herds with either a history or a strong likelihood of paratuberculosis infection were selected by a veterinary team over 2 years. Faecal samples (290) were collected and screened for MAP by a conventional culture method and two PCR assays. In order to further evaluate the usefulness of molecular testing, a nested PCR was also assessed. RESULTS: M. paratuberculosis was isolated and cultured from 23 faecal samples (7.9%) on solid medium. From a molecular perspective, 105 faecal samples (36%) were PCR positive for MAP specific DNA. A complete correlation (100%) was observed between the results of both molecular targets (IS900 and ISMAP02). Sensitivity was increased by ~10% with the inclusion of a nested PCR for ISMAP02 (29 further samples were positive). When culturing and PCR were retrospectively compared, every culture positive faecal sample also yielded a PCR positive result for both targets. Alternatively, however not every PCR positive sample (n = 105, 36%) produced a corresponding culture isolate. Interestingly though when analysed collectively at the herd level, the correlation between culture and PCR results was 100% (ie every herd which recorded at least 1 early PCR +ve result later yielded culture positive samples within that herd). CONCLUSION: PCR on bovine faecal samples is a fast reliable test and should be applied routinely when screening for MAP within herds suspected of paratuberculosis. Nested PCR increases the threshold limit of detection for MAP DNA by approximately 10% but proved to be problematic in this study. Although slow and impractical, culturing is still regarded as one of the most reliable methods for detecting MAP among infected cattle.

Comparison of complications in transtrochanteric and anterolateral approaches in primary total hip arthroplasty.

Three surgical approaches to primary total hip arthroplasty (THA) have been in use since Charnley popularized the transtrochanteric approach. This study was designed to examine the difference in morbidity between the transtrochanteric approach and the anterolateral approach in primary THA. Information on 891 patients who underwent primary THA performed by a single surgeon was collected prospectively between 1998 and 2003 using a modified SF-36 form, preoperatively, intraoperatively, and at 3 months postoperatively. The transtrochanteric group had higher morbidity and more patients who were dissatisfied with their THA. There was a greater range of motion in the anterolateral group.