Evaluation of two commercial, rapid, ELISA kits testing for scrapie in retro-pharyngeal lymph nodes in sheep

AIMS

To estimate the number of cases of scrapie that would occur in sheep of different prion protein (PrP) genotypes if scrapie was to become established in New Zealand, and to compare the performance of two commercially available, rapid ELISA kits using ovine retro-pharyngeal lymph nodes (RLN) from non-infected and infected sheep of different PrP genotypes.

METHODS

Using published data on the distribution of PrP genotypes within the New Zealand sheep flock and the prevalence of cases of scrapie in these genotypes in the United Kingdom, the annual expected number of cases of scrapie per genotype was estimated, should scrapie become established in New Zealand, assuming a total population of 28 million sheep. A non-infected panel of RLN was collected from 737 sheep from New Zealand that had been culled, found in extremis or died. Brain stem samples were also collected from 131 of these sheep. A second panel of infected samples comprised 218 and 117 RLN from confirmed scrapie cases that had originated in Europe and the United States of America, respectively. All samples were screened using two commercial, rapid, transmissible spongiform encephalopathy ELISA kits: Bio-Rad TeSeE ELISA (ELISA-BR), and IDEXX HerdChek BSE-Scrapie AG Test (ELISA-ID).

RESULTS

If scrapie became established in New Zealand, an estimated 596 cases would occur per year; of these 234 (39%) and 271 (46%) would be in sheep carrying ARQ/ARQ and ARQ/VRQ PrP genotypes, respectively. For the non-infected samples from New Zealand the diagnostic specificity of both ELISA kits was 100%. When considering all infected samples, the diagnostic sensitivity was 70.4 (95% CI=65.3-75.3)% for ELISA-BR and 91.6 (95% CI=88.2-94.4)% for ELISA-ID. For the ARQ/ARQ genotype (n=195), sensitivity was 66.2% for ELISA-BR and 90.8% for ELISA-ID, and for the ARQ/VRQ genotype (n=107), sensitivity was 81.3% for ELISA-BR and 98.1% for ELISA-ID.

CONCLUSIONS

In this study, the ELISA-ID kit demonstrated a higher diagnostic sensitivity for detecting scrapie in samples of RLN from sheep carrying scrapie-susceptible PrP genotypes than the ELISA-BR kit at comparable diagnostic specificity.

CLINICAL RELEVANCE

The diagnostic performance of the ELISA-ID kit using ovine RLN merits the consideration of including this assay in the national scrapie surveillance programme in New Zealand.

Flexible dosing with fesoterodine 4 and 8 mg: a systematic review of data from clinical trials

AIMS

To systematically review dose-escalation data from flexible-dose studies of fesoterodine and summarise factors associated with dose-escalation decisions.

METHODS

A PubMed search was conducted using the terms (fesoterodine AND flexible dose), with no limits. Articles were included if they contained fesoterodine dose-escalation data for efficacy or safety outcomes or factors associated with dose-escalation decisions.

RESULTS

Of 13 articles identified by the search, 10 articles (six clinical studies) met inclusion criteria. In flexible-dose trials of fesoterodine, 51-63% of subjects initially receiving fesoterodine 4 mg opted for dose escalation to fesoterodine 8 mg. Escalators generally reported significantly more severe overactive bladder (OAB) symptoms, greater OAB symptom bother and worse health-related quality of life at baseline than non-escalators. Escalators demonstrated less treatment benefit with fesoterodine 4 mg than non-escalators. Non-escalators generally had a higher rate of dry mouth and constipation with fesoterodine 4 mg than escalators. The decision to escalate appeared to be determined by the efficacy/tolerability responses; fesoterodine escalators demonstrated a lower sensitivity (less efficacy and fewer adverse events) before their decision to escalate. By study end (8-11 weeks after escalation decision), the efficacy and tolerability profiles were similar in escalators and non-escalators.

CONCLUSIONS

Data from flexible-dose studies provide strong evidence that fesoterodine provides treatment benefit to individual subjects with OAB because of its true dose-response effect. In clinical practice, it can be worthwhile to escalate to fesoterodine 8 mg in individual subjects who require additional efficacy benefit.

Salmonella serotypes isolated from pet chews in New Zealand

AIMS

To survey the prevalence of Salmonella in imported and domestic pet chews for assessing their potential in introducing novel pathogenic and antimicrobial resistant Salmonella serotype clones into New Zealand, and as vehicles of salmonellosis in the domestic home environment.

METHODS AND RESULTS

Three hundred samples, each of imported and domestic pet chews, were examined bacteriologically for the presence of Salmonella. Salmonella cells in the pre-enrichment culture were concentrated by using Dynabeads, and then selective enrichment and plating were performed by a method described in the Bacteriological and Analytical Manual, USFDA. Salmonella was isolated from 16 (5.3%) of the imported and 20 (6.7%) of the domestic pet chews, but the prevalences of Salmonella in imported and domestic products were not significantly different. All Salmonella isolates were serotyped and genotyped by pulsed-field gel electrophoresis and antimicrobial susceptibility determined by the Clinical and Laboratory Standards Institute disc diffusion methods. Salmonella Borreze has never been recorded earlier in New Zealand and was detected from Australian raw hide. Three isolates of Salmonella London were resistant to ampicillin and gentamicin, and two isolates of Salmonella Infantis were resistant to nalidixic acid, one of which was also resistant to streptomycin.

CONCLUSIONS

Novel pathogenic and antimicrobial-resistant Salmonella are being introduced into New Zealand through the import of pet chews. This indicates that pet chews are a potential source of exposure to Salmonella in the domestic home environment.

SIGNIFICANCE AND IMPACT OF THE STUDY

Contaminated pet chews are potential sources of Salmonella infection for domestic pets, and humans are at risk of exposure either directly by contact through handling or inadvertently by cross-contamination of food or food-contact surfaces in home environments.

The importance of accurate assessment and conservative management of the open bladder neck in patients with post-pelvic fracture membranous urethral distraction defects

OBJECTIVE

To review the pre-operative assessment of bladder neck competence and assess the success of non-operative management of the bladder neck in patients with pelvic fracture membranous urethral distraction defects.

PATIENTS AND METHODS

A series of four patients with long-standing post-pelvic fracture urethral distraction defects and open bladder necks demonstrated on pre-operative investigation are presented.

RESULTS

All four patients were managed by perineal urethroplasty without surgery to the bladder neck. All patients were continent post-operatively despite the injury having ablated the distal sphincter mechanism.

CONCLUSION

We believe that the majority of patients can be managed successfully by a non-operative approach to the bladder neck, sparing them the unnecessary operative morbidity of an abdomino-perineal repair, which should be reserved for those with obviously scarred or distorted bladder necks.

Idiopathic reduced bladder storage versus interstitial cystitis

Idiopathic reduced bladder storage is a term we used to describe a group of patients who have subjective and objective evidence (by cystometrogram) of diminished bladder capacity without a demonstrable cause. We performed a prospective study comparing this condition with interstitial cystitis. We studied the clinical, urodynamic and histological features, and response to therapy in these 2 groups of patients. No statistical difference was found between the incidence of irritative bladder symptoms and/or suprapubic pain. Only minor differences were noted in the maximum cystometric capacity and incidence of bladder instability. Histological and immunofluorescent features were analogous. Also, the reduced bladder storage and interstitial cystitis patients responded similarly to bladder dilation and pharmacological therapy. Augmentation ileocystoplasty used in patients refractory to medical treatment produced comparable results in the short term. Based upon similar findings, it is likely that these 2 conditions represent the same disease entity with the only difference being the cystoscopic findings.