Effect of mucin 4 allele on susceptibility to experimental infection with enterotoxigenic F4 Escherichia coli in pigs fed experimental diets.

BACKGROUND: This study investigated the validity of the DNA-marker based test to determine susceptibility to ETEC-F4 diarrhoea by comparing the results of two DNA sequencing techniques in weaner pigs following experimental infection with F4 enterotoxigenic Escherichia coli (ETEC-F4). The effects of diet and genetic susceptibility were assessed by measuring the incidence of piglet post-weaning diarrhoea (PWD), faecal E. coli shedding and the diarrhoea index. RESULTS: A DNA marker-based test targeting the mucin 4 gene (MUC4) that encodes F4 fimbria receptor identified pigs as either fully susceptible (SS), partially or mildly susceptible (SR), and resistant (RR) to developing ETEC-F4 diarrhoea. To further analyse this, DNA sequencing was undertaken, and a significantly higher proportion of C nucleotides was observed for RR and SR at the XbaI cleavage site genotypes when compared to SS. However, no significant difference was found between SR and RR genotypes. Therefore, results obtained from Sanger sequencing retrospectively allocated pigs into a resistant genotype (MUC4-), in the case of a C nucleotide, and a susceptible genotype (MUC4+), in the case of a G nucleotide, at the single nucleotide polymorphism site. A total of 72 weaner pigs (age ~ 21 days), weighing 6.1 ± 1.2 kg (mean ± SEM), were fed 3 different diets: (i) positive control (PC) group supplemented with 3 g/kg zinc oxide (ZnO), (ii) negative control (NC) group (no ZnO or HAMSA), and (iii) a diet containing a 50 g/kg high-amylose maize starch product (HAMSA) esterified with acetate. At days five and six after weaning, all pigs were orally infected with ETEC (serotype O149:F4; toxins LT1, ST1, ST2 and EAST). The percentage of pigs that developed diarrhoea following infection was higher (P = 0.05) in MUC4+ pigs compared to MUC4- pigs (50% vs. 26.8%, respectively). Furthermore, pigs fed ZnO had less ETEC-F4 diarrhoea (P = 0.009) than pigs fed other diets, however faecal shedding of ETEC was similar (P > 0.05) between diets. CONCLUSION: These results confirm that MUC4+ pigs have a higher prevalence of ETEC-F4 diarrhoea following exposure, and that pigs fed ZnO, irrespective of MUC4 status, have reduced ETEC-F4 diarrhoea. Additionally, sequencing or quantifying the single nucleotide polymorphism distribution at the XbaI cleavage site may be more reliable in identifying genotypic susceptibility when compared to traditional methods.

Antimicrobial Resistance in Leptospira, Brucella, and Other Rarely Investigated Veterinary and Zoonotic Pathogens.

Leptospira, Brucella, and Borrelia are major agents of zoonotic disease, causing high morbidity and, in some cases, significant mortality in humans. For all three genera, prompt diagnosis and appropriate antimicrobial therapy are required to prevent the development of chronic, debilitating illness. Leptospira spp. are intrinsically resistant to several antimicrobial classes; however, there is little evidence in the literature for development of acquired resistance to antimicrobial agents used for clinical treatment of acute leptospirosis. For Brucella infections, there are numerous reports of relapses following therapy, but it is unclear whether this is due to sequestration within infected sites (e.g., bone) or the development of acquired resistance. Brucella have maintained their susceptibility to doxycycline and rifampicin, which in combination remain the most common treatments of brucellosis in humans. In vitro induced point mutations are described as imparting resistance to rifampicin (rpoB) and fluoroquinolones (gyrA). The clinical significance of these mutations is unclear. For Borrelia burgdorferi, although acquired resistance to some antimicrobial agents has been described, resistance due to bacterial persister cells surviving in the presence of antimicrobial, with no apparent increase in the MIC of the organism, have been recently described. Of the remaining veterinary fastidious pathogens, Lawsonia intracellularis is the most interesting from an antimicrobial resistance perspective because it can only be grown in cell culture, making in vitro susceptibility testing challenging. MIC testing has been undertaken on a small number of isolates, and some differences in susceptibility to macrolides have been demonstrated between isolates obtained from different regions.

Giardia duodenalis mouse model for the development of novel antigiardial agents.

This study describes a neonatal mouse model of Giardia infection for development of novel antigiardials. Mice were infected with the axenically cultured Assemblage A BAH2c2 strain, with 105 trophozoites per animal recovered. This model proved to be robust and consistent for use in preliminary drug efficacy trials and drug development.

A Correlational Study of Spiritual Well-being and Depression in the Adult Cancer Patient.

Depression in adult cancer patients has been widely studied, along with spiritual effects of traumatic events and even spiritual growth after a diagnosis of cancer. There has been limited research determining a direct correlation between spiritual well-being and depression in adult cancer patients. The purpose of this research study was to examine the relationship between spiritual well-being and depression in adult cancer patients. This was a descriptive correlational study using 59 patients older than 18 years from an outpatient cancer center. The researchers hypothesized that patients with a low spiritual well-being score would be more likely to have a high depressive symptom score, thus providing support for a correlation between cancer patient's spiritual well-being and risk of depression. Implications of this study lead to evidence for better screening processes for cancer patients regarding spiritual well-being.