Nicole Kemper

Shiga toxin producing Escherichia coli: identification of non-O157:H7-Super-Shedding cows and related risk factors

BackgroundShiga toxin producing Escherichia coli (STEC) are an important cause of human gastro-enteritis and extraintestinal sequelae, with ruminants, especially cattle, as the major source of infection and reservoir. In this study, the fecal STEC shedding of 133 dairy cows was analyzed over a period of twelve months by monthly sampling with the aim to investigate shedding patterns and risk factors.ResultsOverall, 24.7% (in total 407) of 1,646 fecal samples were tested positive for stx by PCR with inner-herd prevalences on the different farms of 11.1% to 32.3%. At individual levels, cows were stx-positive on zero to eight consecutive samplings. According to a strictly longitudinal definition of Super-Shedding, in the present study 14 cows were identified as Super-Shedders of non-O157 serotypes.Significant risk factors for the shedding of STEC were the month of sampling, the number of lactations and days in lactation, the nutritional condition, the somatic cell count and the content of protein in milk. Most notably, the presence of STEC Super-Shedding cows in the herd was a significant risk factor, revealing that STEC Super-Shedding is not restricted to STEC O157:H7 alone.ConclusionsThese data have implications for possible interventions, as removing single non-O157:H7 STEC Super-Shedding cattle from farms would significantly reduce STEC burden.

Campylobacter spp., Enterococcus spp., Escherichia coli, Salmonella spp., Yersinia spp., and Cryptosporidium oocysts in semi-domesticated reindeer (Rangifer tarandus tarandus) in Northern Finland and Norway

The specific aim of this study was to assess the faecal shedding of zoonotic enteropathogens by semi-domesticated reindeer (Rangifer tarandus tarandus) to deduce the potential risk to human health through modern reindeer herding. In total, 2,243 faecal samples of reindeer from northern regions of Finland and Norway were examined for potentially enteropathogenic bacteria (Campylobacter species, Enterococcus species, Escherichia coli, Salmonella species and Yersinia species) and parasites (Cryptosporidium species) in accordance with standard procedures. Escherichia coli were isolated in 94.7%, Enterococcus species in 92.9%, Yersinia species in 4.8% of the samples and Campylobacter species in one sample only (0.04%). Analysis for virulence factors in E. coli and Yersinia species revealed no pathogenic strains. Neither Salmonella species nor Cryptosporidium oocysts were detected. The public health risk due to reindeer husbandry concerning zoonotic diseases included in this study has to be considered as very low at present but a putative epidemiological threat may arise when herding conditions are changed with respect to intensification and crowding.

Bacteria of pathogenic importance in faeces from cadavers of free-ranging or corralled semi-domesticated reindeer in northern Norway.

There is little information on bacteria that have the potential to cause disease in reindeer husbandry. In this project, faecal samples from 35 free-ranging or corralled reindeer, adults and calves, that died in the winter of 2000 in northern Norway, were examined for the occurrence of Campylobacter spp., Clostridium perfringens, Listeria spp., Salmonella spp. and Yersinia spp. to evaluate the role of these microrganisms in loss and mortality in reindeer husbandry. In addition, 31 of these samples were examined for the occurrence of bacteria producing shigatoxin-1 and 2. C. perfringens was isolated in 20 (57.1%) of the faecal samples. In the free-ranging reindeer, 44% were positive carriers of C. perfringens and 90% of the corralled ones were positive for C. perfringens. In addition, the gene encoding for shigatoxin-1 was detected in one of the samples derived from a corralled reindeer. The other bacteria investigated were not found. Shigatoxin-1-producing bacteria were isolated for the first time from reindeer in Norway. However, no correlation between C. perfringens or shigatoxin-1-producing bacteria and mortality in the reindeer could be established.

Risk factors for Salmonella infection in fattening pigs - an evaluation of blood and meat juice samples.

The main objective of this study was to analyse potential herd‐level factors associated with the detection of Salmonella antibodies in fattening pigs. Two independent datasets, consisting of blood and meat juice samples respectively, were used. Additional information about husbandry, management and hygiene conditions was collected by questionnaire for both datasets. The serological analysis showed that 13.8% of the blood samples and 15.7% of the meat juice samples had to be classified as Salmonella‐positive. Logistic‐regression models were used to assess statistically significant risk factors associated with a positive sample result. The results of the statistical blood sample analysis showed that the application of antibiotics increased the odds ratio (OR) by a factor of 5.21 (P < 0.001) compared to untreated pigs. A fully slatted floor decreased the prevalence of Salmonella as well as the use of protective clothing or the cleaning of the feed tube (ORs 0.35–0.54, P < 0.001). It was shown that a distance of less than 2 km to other swine herds increased the chance of a positive Salmonella result (OR = 3.76, P < 0.001). The statistical analysis of the meat juice samples revealed the importance of feed aspects. The chance of obtaining a positive meat juice sample increased by a factor of 3.52 (P < 0.001) by using granulated feed instead of flour. It also became clear that liquid feeding should be preferred to dry feeding (OR = 0.33, P < 0.001). A comparison of the blood sample analysis to the meat juice model revealed that the latter was less powerful because data structure was less detailed. The expansion of data acquisition might solve these problems and improve the suitability of QS monitoring data for risk factor analyses.

Bacteria in milk from anterior and posterior mammary glands in sows affected and unaffected by postpartum dysgalactia syndrome (PPDS)

BackgroundThe performance of piglet weight gain is strongly dependent on the sows ability to meet the demand for adequate milk. Postparturient disorders, especially those subsumed under the term postpartum dysgalactia syndrome (PPDS), can alter or reduce the milk production sensitively, resulting in starving piglets. The aim of this study was to gather further information about the prevalence of different bacterial species in the anterior and posterior mammary glands of sows with respect to the clinical appearance of PPDS.MethodsIn this study, the health status of 56 sows after farrowing was determined with special regard to mastitis and dysgalactia. Pooled milk samples from anterior and posterior glands were taken from both affected and non-affected animals and analysed bacteriologically for the presence of a wide spectrum of different pathogens.ResultsMainly Escherichia coli, staphylococci and streptococci were detected in high percentages but without significant differences in healthy and diseased animals and anterior and posterior glands. However, the large percentages of coliform bacteria suggested a transmission route via faecal contamination.ConclusionIn this study, the prevalence of different bacteria in anterior and posterior glands in PPDS positive and negative sows was analysed. No significant differences in bacteria of healthy and diseased sows were assessed. Therefore, the development of clinical PPDS and actual infection seems to be largely dependant on individual resistance in single sows.

In vitro evaluation of aspirin-induced HspB1 against heat stress damage in chicken myocardial cells.

To understand the potential association of heat stress resistance with HspB1 induction by aspirin (ASA) in chicken myocardial cells, variations of HspB1 expression and heat stressed-induced damage of myocardial cells after ASA administration were studied in primary cultured myocardial cells. Cytopathological lesions as well as damage-related enzymes, such as creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH), indicated the considerable protective ability of ASA pre-treatment against acute heat stress. Immunostaining assays showed that heat stress caused HspB1 to relocate into the nucleus, while ASA did not. ELISA analysis, revealed that HspB1 expression induced by ASA averaged 45.62-fold higher than that of the control. These results indicated that the acute heat-stressed injuries were accompanied by comparatively lower HspB1 expression caused by heat stress in vitro. ASA pre-treatment induced a level of HspB1 presumed to be sufficient to protect myocardial cells from acute heat stress in the extracorporal model, although more detailed mechanisms will require further investigation.

Behavioral phenotyping of minipigs transgenic for the Huntington gene.

BACKGROUND While several novel therapeutic approaches for HD are in development, resources to conduct clinical trials are limited. Large animal models have been proposed to improve assessment of safety, tolerability and especially to increase translational reliability of efficacy signals obtained in preclinical studies. They may thus help to select candidates for translation to human studies. We here introduce a battery of novel tests designed to assess the motor, cognitive and behavioral phenotype of a transgenic (tg) HD minipig model. NEW METHODS A group of tgHD and wildtype (wt) Libechov minipigs (n=36) was available for assessment with (1) a gait test using the GAITRite(®) automated acquisition system, (2) a hurdle-test, (3) a tongue coordination test, (4) a color discrimination test, (5) a startbox back and forth test and (6) a dominance test. Performance of all tests and definition of measures obtained is presented. RESULTS Minipigs were able to learn performance of all tests. All tests were safe, well tolerated and feasible. Exploratory between group comparisons showed no differences between groups of tgHD and wt minipigs assessed, but low variability within and between groups. COMPARISON WITH EXISTING METHOD(S) So far there are no established or validated assessments to test minipigs in the domains described. CONCLUSIONS The data shows that the tests presented are safe, well tolerated and all measures defined can be assessed. Prospective longitudinal application of these tests is warranted to determine their test-retest reliability, sensitivity and validity in assessing motor, cognitive and behavioral features of tg and wt minipigs.

Aspirin-induced heat stress resistance in chicken myocardial cells can be suppressed by BAPTA-AM in vitro

Our recent studies have displayed the protective functions of aspirin against heat stress (HS) in chicken myocardial cells, and it may be associated with heat shock proteins (HSPs). In this study, we further investigated the potential role of HSPs in the aspirin-induced heat stress resistance. Four of the most important HSPs including HspB1 (Hsp27), Hsp60, Hsp70, and Hsp90 were induced by aspirin pretreatment and were suppressed by BAPTA-AM. When HSPs were induced by aspirin, much slighter HS injury was detected. But more serious damages were observed when HSPs were suppressed by BAPTA-AM than those cells exposed to HS without BAPTA-AM, even the myocardial cells have been treated with aspirin in prior. Comparing to other HSPs, HspB1 presented the largest increase after aspirin treatments, 86-fold higher than the baseline (the level before HS). These findings suggested that multiple HSPs participated in aspirin’s anti-heat stress function but HspB1 may contribute the most. Interestingly, during the experiments, we also found that apoptosis rate as well as the oxidative stress indicators (T-SOD and MDA) was not consistently responding to heat stress injury as expected. By selecting from a series of candidates, myocardial cell damage-related enzymes (CK-MB and LDH), cytopathological tests, and necrosis rate (measured by flow cytometry assays) are believed to be reliable indicators to evaluate heat stress injury in chicken’s myocardial cells and they will be used in our further investigations.

HSP90 gene expression induced by aspirin is associated with damage remission in a chicken myocardial cell culture exposed to heat stress

Abstract To understand the potential protection of heat shock protein 90 (HSP90) induced by aspirin against heat stress damage in chicken myocardial cells, enzyme activities related to stress damage, cytopathological changes, the expression and distribution of HSP90, and HSP90 mRNA levels in the myocardial cells exposed to heat stress (42°C) for different durations with or without aspirin administration (1 mg/ml, 2 h prior) in vitro were investigated. Significant increase of enzyme levels in the supernatant of heat-stressed myocardial cells and cellular lesions characterised by acute degeneration, karyopyknosis and karyorrhexis were observed, compared to non-treated cells. However, the lesions of cells treated with aspirin were milder, characterised by earlier recovery of enzyme levels to the control levels and no obvious heat stress-related cellular necrosis. Stronger positive signals in the cytoplasm and longer retention of HSP90 signal in nuclei were observed in aspirin-treated myocardial cells than those of only heat-stressed cells. HSP90 level in the aspirin-treated myocardial cells was 11.1-fold higher than that in non-treated cells, and remained at a high level at the early stage of heat stress, whereas it was just 4.1-fold higher in only heat-stressed cells and returned rapidly to a low level. Overexpression of HSP90 mRNA in aspirin-treated cells was observed throughout the experiment, whereas HSP90 mRNA decreased significantly only in heat-stressed cells. The early higher HSP90 expression induced by aspirin during heat stress was accompanied by decreased heat stress damage, suggesting that aspirin might play an important role in preventing myocardial cells from heat stress damage in vitro.

Prevalence of enteropathogenic bacteria and Cryptosporidium species in moose (Alces alces) in Norway

MENG, X. J., PAUL, P. S., HALBUR, P. G. & LUM, M. A. (1995) Phylogenetic analysis of the putative M (ORF6) and N (ORF7) genes of porcine reproductive and respiratory syndrome virus (PRRSV): implication for the existence oftwo genotypes of PRRSV in the USA and Europe. Archives of Virology 140, 745-755 PRIETO, C., SANCHEZ, R., MARTIN-RILLO, S., SUAREZ, P., SIMARRO, I. & CASTRO, J. M. (1996a) Exposure of gilts in early gestation to porcine reproductive and respiratory syndrome virus. Veterinary Record 138,536-539 PRIETO, C., SUAREZ, P., BAUTISTA, J. M., SANCHEZ, R., RILLO, S. M., SIMARRO, I., SOLANA,A. & CASTRO, J. M. (1996b) Semen changes in boars after experimental infection with porcine reproductive and respiratory syndrome (PRRS) virus. Theriogenology 45, 383-395 ROSSOW, K. D. BAUTISTA, E. M., GOYAL, S. M., MOLITOR, T. W., MURTAUGH, M. P., MORRISON, R. B., BENFIELD, D. A. & COLLINS, J. E. (1994) Experimental porcine reproductive and respiratory syndrome virus infection in one-, four-, and 10-week-old pigs. Journal of Veterinary Diagnostic Investigation 6, 3-12 SWENSON, S. L., HILL, H. T., ZIMMERMAN, J. J., EVANS, L. E., LANDGRAF, J. G., WILLS, R. W., SANDERSON, T. P., MCGINLEY, M. J., BREVIK, A. K., CISZEWSKI, D. K. & FREY, M. L. (1994) Excretion of porcine reproductive and respiratorysyndrome virus in semen after experimentally induced infection in boars. Journal of theAmerican Veterinary Medical Association 204, 1943-1948 WAGSTROM, E. A., CHANG, C. C., YOON, K. J. & ZIMMERMAN, J. J. (200 1) Shedding of porcine reproductive and respiratory syndrome virus in mammary gland secretions of sows. American Journal of Veterinary Research 62, 1876-1880 WILLS, R. W., ZIMMERMAN, J. J., YOON, K. J., SWENSON, S. L., HOFFMAN, L. J., MCGINLEY, M. J., HILL, H. T., PLATT, K. B., CHRISTOPHER-HENNINGS, J. & NELSON, E. A. (1997a) Porcine reproductive and respiratory syndrome virus: a persistent infection. Veterinary Microbiology 55, 231-240 WILLS, R. W., ZIMMERMAN, J. J., YOON, K. J., SWENSON, S. L., MCGINLEY, M. J., HILL, H. T. & PLATT, K. B. (1997b) Porcine reproductive and respiratory syndrome virus: routes of excretion. Veterinary Microbiology 57, 69-81 YOON, K. J., JOO, H. S., CHRISTIANSON, W. T., MORRISON, R. B. & DIAL, G. D. (1993) Persistent and contact infection in nursery pigs experimentally infected with porcine reproductive and respiratory syndrome (PRRS) virus. Swine Health and Production 1, 5-8