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101.
The ability of many bacteria to adapt to stressful conditions may later protect them against the same type of stress (specific adaptive response) or different types of stresses (multiple adaptive response, also termed cross-protection). Arcobacter butzleri and Campylobacter jejuni are close phylogenetic relatives that occur in many foods of animal origin and have been linked with human illness (mainly diarrhoea). In the present study, sublethal stress adaptation temperatures (48 °C and 10 °C) and mild and lethal acid conditions (pH 5.0 and pH 4.0) were determined for A. butzleri and C. jejuni. In addition, it was evaluated whether these sublethal stress adaptations cause specific adaptive responses or cross-protection against subsequent mild or lethal acid stresses in these bacteria. The studies were conducted in broth adjusted to the different conditions and the results were determined by the dilution series plating method. It was shown that heat stress adapted A. butzleri (incubated for 2 h at 48 °C) were significantly more resistant to subsequent lethal acid stress (pH 4.0) than non-adapted cells at the 1 h time-point (p < 0.01 in Wilcoxon rank sum test). No specific adaptive responses against the stresses in A. butzleri or C. jejuni and no cross-protection in C. jejuni were found. The ability of heat stressed A. butzleri to tolerate later lethal acid conditions should be taken into account when designing new food decontamination and processing strategies. 相似文献
102.
目的研究北京市顺义区鸡胴体中弯曲菌分布和分子特征,为顺义区弯曲菌防控提供科学依据。方法采集批发市场和零售店鸡胴体60份,采用滤膜法分离培养弯曲菌,对分离菌株进行多位点序列分型分析并构建最小生成树。结果鸡胴体中弯曲菌检出率为75.0%(45/60),空肠弯曲菌与结肠弯曲菌占比分别为38.0%(19/50)和62.0%(31/50)。批发市场和零售店弯曲菌检出率分别为86.0%(37/43)和47.1%(8/17),差异有统计学意义(χ~2=9.877,P0.05);5~7月空肠弯曲菌检出率分别为10.0%(2/20)、40.0%(8/20)和45.0%(9/20),差异有统计学意义(χ~2=6.624,P0.05)。19株空肠弯曲菌共分为13个ST型;28株结肠弯曲菌共分为16个ST型。空肠弯曲菌耐药率前五位由高至低依次为四环素(100.0%,19/19)、萘啶酸(100.0%,19/19)、环丙沙星(94.7%,18/19)、氟苯尼考(57.9%,11/19)、庆大霉素(36.8%,7/19);结肠弯曲菌耐药率前五位由高至低依次为萘啶酸(100.0%,31/31)、环丙沙星(100.0%,31/31)、四环素(93.5%, 29/31)、链霉素(93.5%, 29/31)、庆大霉素(83.9%,26/31)。空肠弯曲菌和结肠弯曲菌多重耐药率分别为68.4%(13/19)和93.5%(29/31)。结论北京市顺义区市场零售鸡胴体中弯曲菌污染水平较高,结肠弯曲菌为污染的优势菌种。批发市场鸡胴体污染弯曲菌的情况比零售店严重。 相似文献
103.
目的 比较国标法和双孔滤膜法在生禽肉中弯曲菌的检测率,探索生禽肉中弯曲菌分离鉴定的有效检测方法.方法 随机采集冷冻和新鲜禽肉产品共102份,通过国标法和双孔滤膜法2种方法检测,观察2种方法从样品处理、增菌和分离培养过程中的不同,并比较2种方法检测弯曲菌检出率的差异.结果 102份样品中国标法检出弯曲菌的检出率为28.4... 相似文献
104.
目的 分析北京市腹泻患者弯曲菌(Campylobacter spp.)分离株的抗生素敏感性和脉冲场凝胶电泳(pulsed field gel electrophoresis,PFGE)分子分型特征.方法 2016—2018年,对北京市19家医院肠道门诊分离的弯曲菌采用琼脂稀释法进行抗生素敏感性检测,按照PulseNet... 相似文献
105.
目的 调查分析浙江金华地区肉鸡屠宰加工过程中空肠弯曲菌的污染现状及规律.方法 选择金华地区6家肉鸡屠宰加工企业,通过直接计数法对空肠弯曲菌定性定量检测,分析其流行病学规律.结果 采集的2139份样品中,泄殖腔、脱毛、取内脏、消毒预冷、包装和速冻等环节样品的空肠弯曲菌阳性率分别为92.48%、83.39%、98.12%、... 相似文献
106.
目的建立含内标的多重实时荧光PCR法同时检测空肠弯曲菌和结肠弯曲菌。方法针对空肠弯曲菌特有hipO基因和结肠弯曲菌特有ceuE基因设计引物探针,设计并优化内标DNA添加量。测试了方法的特异性、灵敏度以及在鸡肉中的检出限。结果内标的最适添加量为10~4copies/PCR。所建立方法对空肠弯曲菌和结肠弯曲菌的灵敏度分别达到4.7copies/PCR和5.23copies/PCR;对115株空肠弯曲菌、49株结肠弯曲菌和42株非目标菌株在3种不同类型的实时荧光PCR仪上的特异性均达到100%;对鸡肉中空肠弯曲菌和结肠弯曲菌的检出限达到10CFU/25g,与传统检测方法一致。采用所建立的方法对50份市售生鲜鸡肉进行检测发现,空肠弯曲菌阳性率为12%(6/50),结肠弯曲菌阳性率为4%(2/50);传统国标检测方法除了1份空肠弯曲菌阳性样品未得到分离确认,其余PCR阳性样品均在平板上分离确认。结论该方法特异性强、灵敏度高、开放性好、含有内标可防止\"假阴性\",可应用于食品中2种重要致病性弯曲菌的快速同步检测。 相似文献
107.
108.
L.A.P. Hoogenboom J.G. Bokhorst M.D. Northolt L.P.L. van de Vijver N.J.G. Broex D.J. Mevius 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2013,30(10):1195-1207
Organic products were analysed for the presence of contaminants, microorganisms and antibiotic resistance and compared with those from conventional products. No differences were observed in the Fusarium toxins deoxynivalenol and zearalenone in organic and conventional wheat, during both a dry period and a very wet period which promoted the production of these toxins. Nitrate levels in head lettuce produced organically in the open field were much lower than those in conventional products. In iceberg lettuce and head lettuce from the greenhouse, no differences were detected. Organically produced carrots contained higher nitrate levels than conventional products. Both organic and conventional products contained no residues of non-polar pesticides above the legal limits, although some were detected in conventional lettuce. Organic products contained no elevated levels of heavy metals. Salmonella was detected in 30% of pig faeces samples obtained from 30 organic farms, similar to the incidence at conventional farms. At farms that switched to organic production more then 6 years ago no Salmonella was detected, with the exception of one stable with young pigs recently purchased from another farm. No Salmonella was detected in faeces at the nine farms with organic broilers, and at one out of ten farms with laying hens. This is comparable with conventional farms where the incidence for Salmonella lies around 10%. Campylobacter was detected in faeces at all organic broiler farms, being much higher than at conventional farms. One of the most remarkable results was the fact that faeces from organic pigs and broilers showed a much lower incidence of antibiotic resistant bacteria, except for Campylobacter in broilers. It is concluded that the organic products investigated scored as equally well as conventional products with regard to food safety and at the same time show some promising features with respect to antibiotic resistance. 相似文献
109.
Abstract: Campylobacter spp. is recognized as one of the most common cause of food‐borne bacterial gastroenteritis in humans. Campylobacter infection causes campylobacteriosis, which can range from asymptomatic to dysentery‐type illnesses with severe complications, such as Guillian‐Barre syndrome. Epidemiological studies have revealed that consumption of poultry products is an important risk factor of this disease. Adherence and cytotoxic activity of the bacteria to host mucosal surfaces have been proposed to be critical steps in pathogenesis. Innovative tools for controlling Campylobacter, such as natural products from plants, represent good alternatives for use in foods or as therapeutic agents. In this study, 28 edible or medicinal plants species were analyzed for their bactericidal effects on the growth of Campylobacter jejuni and C. coli. The extracts of Acacia farnesiana, Artemisia ludoviciana, Opuntia ficus‐indica, and Cynara scolymus were the most effective against these microorganisms at minimal bactericidal concentrations (MBCs) of 0.3, 0.5, 0.4, and 2.0 mg/mL, respectively. No effect on growth was detected with lower concentrations of extract (25%, 50%, or 75% of the MBC) added to the media. The effect of each extract (75% of the MBC) on adherence and cytotoxicity of C. jejuni and C. coli was evaluated in Vero cells. Adherence of Campylobacter to Vero cells was significantly affected by all the extracts. Cytotoxic activity of bacterial cultures was inhibited by A. farnesiana and A. ludoviciana. These plant extracts are potential candidates to be studied for controlling Campylobacter contamination in foods and the diseases associated with this microorganism. Practical Application: Innovative tools for controlling Campylobacter, such as natural products from plants, represent good alternatives for use in foods or as therapeutic agents. The extracts of Acacia farnesiana, Artemisia ludoviciana, Opuntia ficus‐indica, and Cynara scolymus were the most effective against these microorganisms. Adherence and cytotoxic activity of the bacteria to host mucosal surfaces which are critical steps in pathogenesis were decreased by these extracts. Our results point to these plants as potential candidates for the control of Campylobacter contamination in foods, the treatment of the diseases associated with this microorganism, and as feed supplements to reduce on‐farm prevalence of Campylobacter. 相似文献
110.