Campylobacter spp., Salmonella spp., Verocytotoxic Escherichia coli,and Antibiotic Resistance in Indicator Organisms in Wild Cervids

Faecal samples were collected, as part of the National Health Surveillance Program for Cervids (HOP) in Norway, from wild red deer, roe deer, moose and reindeer during ordinary hunting seasons from 2001 to 2003. Samples from a total of 618 animals were examined for verocytotoxic E. coli (VTEC); 611 animals for Salmonella and 324 animals for Campylobacter. A total of 50 samples were cultivated from each cervid species in order to isolate the indicator bacterial species E. coli and Enterococcus faecalis/E. faecium for antibiotic resistance pattern studies. Salmonella and the potentially human pathogenic verocytotoxic E. coli were not isolated, while Campylobacter jejuni jejuni was found in one roe deer sample only. Antibiotic resistance was found in 13 (7.3%) of the 179 E. coli isolates tested, eight of these being resistant against one type of antibiotic only. The proportion of resistant E. coli isolates was higher in wild reindeer (24%) than in the other cervids (2.2%). E. faecalis or E. faecium were isolated from 19 of the samples, none of these being reindeer. All the strains isolated were resistant against one (84%) or more (16%) antibiotics. A total of 14 E. faecalis-strains were resistant to virginiamycin only. The results indicate that the cervid species studied do not constitute an important infectious reservoir for either the human pathogens or the antibiotic resistant microorganisms included in the study.     

Surveillance of verocytotoxigenic Escherichia coli in Irish bovine dairy herds

Verocytotoxigenic Escherichia coli (VTEC) are highly significant zoonotic threats to public health, and have been the causative agent implicated in numerous high-profile outbreaks affecting large numbers of people. Serovar O157 is most frequently linked with human illness; however, other serovars, such as O26, O103, O111 and O145, have also been implicated. This study aimed to characterize the prevalence and virulence determinants of these five serovars in Irish dairy farm herds, and their milk. Using real-time PCR (RTi-PCR), bovine rectal faecal swabs and raw milk samples, along with milk filters, were screened for the presence of vt genes. Positive samples were then screened for the five serovars using sero-specific PCR. Serovar-positive samples were subjected to immunomagnetic separation, to isolate viable VTEC strains. These isolates were subsequently screened for four virulence factors: vt1, vt2, eaeA and hlyA. Three hundred and eighty six of the 600 rectal faecal swabs, 85 of the 117 milk-filters and 43 of the 120 bulk-tank milk samples, were positive for vt genes. From these 514 total vt-positive samples, 58 O26, 162 O103, 1 O111, 324 O145 and 26 O157 positives were detected by sero-specific RTi-PCR. Immunomagnetic separation yielded 12 O26, 26 O103, 0 O111, 19 O145 and 10 O157 isolates. Ten of these isolates contained at least one of the four virulence determinants screened for (i.e. vt1, vt2, eaeA and hlyA). Of these 10 isolates, pulsed-field gel electrophoresis showed that two of the O26 isolates from different farms were indistinguishable. Two O157 isolates were also indistinguishable. This study found serovars O103 and O145 to be the most prevalent in samples tested. Apart from the occurrence of VTEC in dairy herds, this study shows a high occurrence of vt genes in the environment, creating the possibility of horizontal gene transfer and emergence of new VTEC strains.     

Longitudinal study to investigate VTEC O157 shedding patterns in young cattle

Individual animal samples were collected from ten VTEC O157 positive farms approximately monthly over 11 months to investigate the shedding of VTEC O157 by youngstock. VTEC O157 was isolated from 7.7% of the 6266 samples and 28.9% of the 1383 animals. On six of the farms VTEC O157 was isolated at multiple visits from several animals, whereas the remaining four farms had one or two positive animals at any one visit, with VTEC isolated from a maximum of four visits. A total of 92 animals were positive more than once (up to four sampling occasions) with a maximum of four negative samples between positive isolations. The results reveal a large variation in individual animal shedding patterns; the proportion of shedding animals on positive farms; and over time within the same farm. The lack of consistent shedding restricts the ability to target potential interventions to specific positive animals/groups or herds.     

多重荧光PCR检测肠出血性大肠杆菌（VTEC）方法的研究

为寻找一种能广泛应用于食品检验、临床诊断的快速、简便、灵敏度高、特异性较好、价格低廉的肠出血性大肠杆菌（VTEC）的检测方法;对VTEC致病相关基因VT1和VT2基因序列进行分析,并设计2对特异引物,通过SYBR GreenⅠ多重荧光PCR反应法结合熔链曲线分析,实现对VTEC的检测;结果表明该方法具有较高的灵敏度及特异性,能够对肠出血性大肠杆菌（VTEC）进行有效检测,其最低检出限可达10cfu/g。利用该技术检测VTEC,具有快速、方便、准确、高效的特点,是一种适于检验检疫和兽医临床检验等领域的快速检测的有效方法。     

断奶仔猪源产Vero细胞毒素大肠杆菌eaeA基因的检测

根据文献合成了一对引物,利用PCR方法检测了84株来自断奶仔猪水肿病例的产Vero细胞毒素大肠杆菌(VerotoxigenicEscherichiacoli,VTEC)的LEE(locusofenterocyteeffacement)毒力岛的eaeA基因,以了解携带LEE毒力岛的大肠埃希菌在江苏省断奶仔猪群VTEC中的流行状况。结果发现:从其中17株中可扩增到预期的DNA片断,证实它们携带LEE毒力岛,携带率为20.24%。数据分析提示:LEE毒力岛的分布不仅限于EPEC和EHEC,在断奶仔猪源VTEC中也有一定的分布,并可能成为重要的毒力因子。     

Prevalence of VTEC O157 in dairy and veal herds and risk factors for veal herds

The aim of this study was to determine the herd prevalence of veal and dairy herds and to identify risk factors for VTEC O157 positive veal herds. The study was based on monitoring data from November 1996 through July 2005 of 1051 dairy herds and 930 veal herds. The herd level prevalence (95% CI) was 8.0% (6.4–9.6) for dairy herds and 12.6% (10.5–14.7) for veal herds. Within the population of veal herds, a prevalence of 39.8% (33.9–45.6) was found for pink veal herds (n = 269) and 1.5% (0.7–2.8) for white veal herds (n = 661).Multivariable logistic regression showed that the type of veal (pink vs. white; OR = 21.6; 95% CI: 10.4–45.0), ventilation (mechanical vs. natural; OR = 0.4; 95% CI: 0.2–0.8), time between arrival in the herd and sampling (3–5 months vs. 0–2 months: OR = 2.33; 95% CI: 1.1–5.1, ≥6 months vs. 0–2 months: OR = 4.11; CI: 1.9–8.9), other feed than the 7 most common (yes vs. no; OR = 2.1; 95% CI: 1.2–3.7) and at least one dog present in the stable (yes vs. no; OR = 2.6; 95% CI: 1.5–4.6) were significantly (P < 0.05) associated with the presence of VTEC O157. The large difference in the VTEC O157 prevalences for pink veal and white veal production might have been caused by a very different management of these type of herds. However, this could not be studied with the data collected.     

Treatment of problem behaviour in dogs and cats by castration and progestagen administration: A review

Summary

Treatment of problem behaviour in companion animals by castration and progestagen administration is reviewed. In male dogs castration is effective in eliminating roaming and, to a lesser extent, mounting, urine marking and intermale agression. Spraying, roaming and fighting behaviour in cats disappear almost completely after castration. In the latter species prepubertal castration does not seem to be more effective in preventing this problem behaviour than postpubertal castration is in eliminating it.

In dogs, intermale aggression, urine marking, mounting and roaming have been treated successfully with progestagens; in cats the same treatment has been successful in decreasing fighting and roaming. There are no reports on the ethical aspects or on adverse side effects of castration. For progestagens a wide range of undesirable side effects have been described. The results of both castration and progestagen therapy differ in the various studies. The underlying mechanism(s) of progestagen influence on behaviour are not understood. Therefore, future research on this topic is necessary.     

An investigation of factors associated with the prevalence of verocytotoxin producing Escherichia coli O157 shedding in Scottish beef cattle

The prevalence of verocytotoxin-producing Escherichia coli (VTEC) O157 in 12-30-month-old beef finishing cattle in Scotland was determined using 1g faeces samples enriched in buffered peptone water, followed by immunomagnetic separation (IMS) and isolation on sorbitol MacConkey agar with cefixime and tellurite supplement (CT-SMAC). A validated questionnaire was used to collect information that could be associated with the samples. Generalised Linear Models and Generalised Linear Mixed Models were used to identify factors associated with shedding both between and within groups. A total of 14,856 samples were collected from 952 farms, of which 1231 were positive for VTEC O157. Prevalence levels were calculated with 95% confidence intervals as follows: 7.9% (6.5%, 9.6%) of animals sampled were estimated to be shedding VTEC O157, while 22.8% (19.6%, 26.3%) of farms were estimated as having at least one animal shedding in the group sampled. The median percentage of animals shedding in positive groups was 25% (20%, 32%). An increased probability of a group containing a shedding animal was associated with larger numbers of finishing cattle, the presence of pigs on the farm, or the farm being classed as a dairy unit stocking beef animals. Farms that spread slurry on grazing land were more likely to have shedding animals, while those that spread manure were at lower risk. Groups with older animals were less likely to be identified as positive. There was no significant regional difference in group shedding probabilities, but the proportion of positive groups dropped over two successive years of the study. Higher mean levels of shedding in positive groups were associated with animals being housed rather than at pasture, and this effect was stronger in groups which had recently had a change in housing or diet. Farms with animals at pasture had lower mean prevalence where water was supplied from a natural source, as had farms with higher numbers of finishing cattle. There remained unexplained variability in mean prevalence levels on positive farms in different areas of Scotland.     

多重荧光PCR检测肠出血性大肠杆菌（VTEC）方法的研究

为寻找一种能广泛应用于食品检验、临床诊断的快速、简便、灵敏度高、特异性较好、价格低廉的肠出血性大肠杆菌(VTEC)的检测方法;对VTEC致病相关基因VT1和VT2基因序列进行分析,并设计2对特异引物,通过SYBR GreenⅠ多重荧光PCR反应法结合熔链曲线分析,实现对VTEC的检测;结果表明该方法具有较高的灵敏度及特异性,能够对肠出血性大肠杆菌(VTEC)进行有效检测,其最低检出限可达10cfu/g。利用该技术检测VTEC,具有快速、方便、准确、高效的特点,是一种适于检验检疫和兽医临床检验等领域的快速检测的有效方法。