Multidrug-Resistant of Escherichia coli and Salmonella spp. Strains in Chicken Feces Intended for Consumption in Open Spaces of Ouagadougou, Burkina Faso

Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales sites. These strains were then characterized using bacteriological and biochemical methods to identify resistant strains. In a study conducted in Ouagadougou, we systematically collected chicken fecal samples from 20 locations across the city, followed by isolation and identification of Salmonella spp. using specific enrichment and culture methods, as well as Escherichia coli. Bacterial strains were characterized using antibiotic resistance profiles were determined through agar diffusion tests, revealing sensitivity or resistance to a range of antibiotics based on established scientific criteria. The results showed that out of the 400 samples collected, 81.25% and 63.5% were contaminated by Escherichia coli and Salmonella spp., respectively. Among these, 86.15% of identified Escherichia coli and 50.78% of Salmonella spp. displayed resistance to at least one tested antibiotic. Among 280 Escherichia coli isolates identified resistant to at least one antibiotic, 31.07% were resistant to cefotaxime (CTX), 20.35% to ceftazidime (CAZ), 21.07% to ceftriaxone (CTR), 75% to amoxicillin clavulanic acid (AMC), 23.57% aztreoname (ATM) and 27.14% were resistant to imipenem (IMP). In the case of the 129 Salmonella spp. isolates resistant to at least one tested antibiotic, 34.88% were resistant to CTX;41.08% to CAZ;35.65% to CTR, 92% to AMC, 39.53% to ATM and finally 47.28% were resistant to IMP. Our study revealed high prevalence of resistance in bacterial strains isolated from local chickens sold outdoors in Ouagadougou. These findings raise significant public health concerns, due to the possible transmission of these resistant strains to humans through the consumption of contaminated meat, thus complicating the treatment of bacterial infections.

Evaluation of the Microbiological Quality of Poultry Imported into Togo and the Antibiotic Resistance of Salmonella spp. Isolated

In Togo, despite the government’s efforts, food requirements in terms of animal proteins are not covered by national production and are subject to huge imports of meat products. However, the hygienic quality of these imports is not guaranteed for the consumer. The aim of this study was to estimate the frequency of unhygienically unsatisfactory imported poultry and to determine the antibiotic resistance profile of Salmonella spp. strains. A total of 285 samples of imported poultry, including 55 chicken thighs, 10 chicken backbones, 25 chicken wings, 5 whole chickens, 30 sausages, 35 chicken forequarters, 95 chicken drumsticks and 30 guinea fowl wings, were analyzed using standard AFNOR routine methods. The following germs were tested: Total Aerobic Mesophilic Flora (TAMF), Anaerobic-Sulfite-Reducing (ASR), Escherichia coli, Staphylococcus aureus and Salmonella spp. Antibiotic susceptibility testing was carried out on Salmonella spp. strains isolated using the agar disk diffusion method (CA-SFM). Results showed 100% compliance for TAMF, coagulase-positive Staphylococci and Escherichia coli. On the other hand, 3.84% and 2.46% non-compliance were recorded for ASR and Salmonella respectively. Non-compliance with hygiene rules is generally thought to be the cause of meat contamination. Seven 7 strains of Salmonella were isolated, 5 of which were of the OMA serogroup, and the other two of the OMB and HMB groups. Antibiotic susceptibility tests revealed resistance to certain beta-lactam antibiotics and quinolones, in particular: cefalexin (28.57%), cefoxitin (14.28%), cefuroxime (28.57%), ceftazidime (28.57%), ceftriaxone (28.57%) and nalidixic acid (28.57%). This result may be explained by the uncontrolled use of B-lactam and quinolone antibiotics in poultry farming. As Salmonella spp. is a pathogenic enteric bacterium that causes food-borne illness in humans, resistance to third-generation cephalosporins remains a major public health problem.

Potential Risk of Transmission of Escherichia coli and Salmonella spp. Infections by the Musca domestica Fly and the Periplaneta americana Cockroach in the City of Cotonou (South Benin)

Background: The occurrence of bacterial infections sometimes involves synanthropic flies and cockroaches, as mechanical vectors of pathogenic microorganisms. The aim of this study was to identify the different species of flies and cockroaches that cohabit with humans in the city of Cotonou and determine the contribution of Musca domestica and Periplaneta americana in the transmission of bacteria responsible for infections in humans. Methods: Capture sessions during the day for flies and at night for cockroaches were carried out in 4 arrondissements of the city of Cotonou. The insects collected were transported to the Center of Research Entomological of Cotonou for identification, then sent to the Section Hygiene of Water and Food for microbiological analysis, enumeration and testing for human pathogenic bacteria. Results: A total of 351 flies and 26 cockroaches were collected at the sites, including two synanthropic species belonging to two families each. Musca domestica and Periplaneta americana were the most abundant species found after identification in the city of Cotonou. Thermo-tolerant coliforms and Escherichia coli were found on all specimens at varying concentrations. Salmonella spp. bacteria were identified in the fly population from the Dantokpa dump. Conclusion: Flies and cockroaches can transmit microorganisms to humans. The presence of Salmonella spp. among the specimens revealed that infections frequently caused by contaminated food or water are also transmitted to humans by flies. The presence of these germs on flies and cockroaches represents a potential risk of mechanical transmission to humans. It is, therefore, essential to continue investigations in order to assess the species of bacteria propagated, improve control strategies against these troublesome insects and adopt better hygiene conditions for better living.

Monitoring of Escherichia coli, Salmonella spp. and Staphylococci in Poultry Meat-Based Fast Food in Saudi Arabia

An investigation was made to survey the possible presence of Staphylococcus aureus, Escherichia coli and Salmonella spp. from fast-food shops in Al-Ahsa Province, Kingdom of Saudi Arabia (KSA), as potential reservoir of human infection and antimicrobial resistance. A total of 100 samples of shawarma poultry meat were collected from different localities of the province. Conventional, commercial VITEK 2 and molecular techniques were used for isolates’ identification and antibiogram detection. Staph aureus was isolated at a rate of 14% and CNS as Staph. sciuri and Staph. xylosus at 2%. E. coli was identified at a rate of 12% and antibiogram analysis showed 41.67% of isolates to be extended-spectrum β-lactamases (ESBL) with evidence of multi-drug resistance (MDR). Molecular analysis of E. coli revealed presence of sero-groups O1 and O2, entero-toxigenic (ETEC), shiga-toxigenic, ST540 and the prototypical ETEC strain H10407 which are potential public health hazard. Salmonella enterica serovar Enteritidis showed 19% prevalence while S. Typhimurium with 8% prevalence. Anti-microbial sensitivity of 15 strains of S. Enteritidis and 5 strains of S. Typhimurium showed multi-drug resistance (MDR).

Edaphoclimatic seasonal trends and variations of the Salmonella spp. infection in Northwestern Mexico

Currently,Salmonella spp.is the bacterium causing the highest number of food-borne diseases(FADs)in the world.It is primarily associated with contaminated water used to that irrigates crops from intensive livestock farming.However,literature emphasizes that the reservoirs for Salmonella spp.remain in wildlife and there are unconventional sources or secondary reservoirs,such as soil.Human soil-borne diseases have not been modeled in spatial scenarios,and therefore it is necessary to consider soil and other climatic factors to anticipate the emergence of new strains or serotypes with potential threat to public and animal health.The objective of this research was to investigate whether edaphic and climatic factors are associated with the occurrence and prevalence of Salmonella spp.in Northwestern Mexico.We estimated the potential distribution of Salmonella spp.with an interpolation method of unsampled kriging areas for 15 environmental variables,considering that these factors have a seasonal dynamic of change during the year and modifications in longer periods.Subsequently,a database was generated with human salmonellosis cases reported in the epidemiological bulletins of the National System of Epidemiological Surveillance(SIVE).For the Northwest region,there were 30,595 human cases of paratyphoid and other salmonellosis reported have been reported in Baja California state,71,462 in Chihuahua,and 16,247 in Sonora from 2002 to 2019.The highest prevalence was identified in areas with higher temperatures between 35 and 37℃,and precipitation greater than 1000 mm.The edaphic variables limited the prevalence and geographical distribution of Salmonella spp.,because the region is characterized by presenting a low percentage of organic matter(≤4.3),and most of the territory is classified as aridic and xeric,which implies that the humidity comprises≤180 days a year.Finally,the seasonal time series indicated that in the states of Baja California and Chihuahua the rainy quarter of the year is 18.7%and 17.01%above a typical quarter respectively,while for Sonora the warmest quarter is 23.3%.It is necessary to deepen the relationship between different soil characteristics and climate elements such as temperature and precipitation,which influence the distribution of different soil-transmitted diseases.

Effects of Sodium Lactate on the Survival of <i>Listeria Monocytogenes</i>, <i>Escherichia coli</i>O157:H7, and <i>Salmonella</i>spp. in Cooked Ham at Refrigerated and Abuse Temperatures

The objective of this study was to determine the effect of sodium lactate on the survival of Listeria monocytogenes, Escherichia coli O157: H7, and Salmonella spp. in cooked ham during storage at refrigerated and abuse temperatures. Cooked ham was added with 0% - 3% lactate, inoculated with a multiple-strain mixture of L. monocytogenes, E. coli O157: H7, or Salmonella spp. and stored at 4oC - 15oC for up to 35 day. The growth of the three pathogens was inhibited in ham containing 3% lactate, and no growth of E. coli O157: H7 and Salmonella spp. occurred at the lowest storage tem- peratures of 6 and 8oC, respectively. In ham containing no lactate, the average growth rates were 0.256 - 0.380 log CFU/day for L. monocytogenes at 4oC - 8oC, 0.242 - 0.315 log CFU/day for E. coli O157: H7 at 8oC - 15oC, and 0.249 - 0.328 log CFU/day for Salmonella spp. at 10oC - 15oC. The addition of 1% or 2% lactate significantly (P < 0.05) reduced the growth rates of the three pathogens, and the effect was more profound at lower temperatures. Salmonella spp. were more sensitive to the effect of lactate than L. monocytogenes and E. coli O157: H7. Polynomial models were developed to describe the growth rates of the three pathogens as affected by the lactate concentration and storage tem- perature. Results from this study demonstrate the effect of lactate on the growth of L. monocytogenes, E. coli O157: H7, and Salmonella spp. in cooked ham and indicate the effective lactate concentrations and storage temperatures that can be used to enhance the microbiological safety of ready-to-eat ham products.

Presence of Multidrug-Resistant <i>E. coli</i>, <i>Enterococcus</i>spp. and <i>Salmonella</i>spp. in Lakes and Fountains of Porto, Portugal

Urban lakes and fountains provide recreational activities that could facilitate the contact between humans, animals and biological agents. The objective of this work was to assess the water quality and safety of 17 lakes and 13 fountains in the city of Porto (Portugal), by detecting the presence of Escherichia coli, enterococci and Salmonella spp., and analyzing their antimicrobial resistance. (For more information,please refer to the pdf.)

Simultaneous Detection of <i>Salmonella</i>spp., <i>Salmonella</i>Enteritidis and <i>Salmonella</i>Typhimurium in Raw Salad Vegetables and Vegetarian Burger Patties

The health risks posed by Salmonella spp., Salmonella Enteritidis and Salmonella Typhimurium through the consumption of raw vegetables and vegetarian burger patties necessitates the needs for the optimization of analytical approach for their detection and enumeration in the raw vegetables, which served as potential vehicles for transmission of these pathogenic microorganisms. We sought to establish a rapid, economic and sensitive method to detect and determine the load of Salmonella spp., Salmonella Enteritidis and Salmonella Typhimurium using the most probable numbers (MPN) in combination with the multiplex polymerase chain reaction (MPCR). From the naturally contaminated one hundred and seventy five samples tested (n = 175), the overall prevalence of Salmonella spp. was 28%, Salmonella Enteritidis was 20% and Salmonella Typhimurium was 14.3%, respectively. The MPN-MPCR is a quantitative method to determine the density of cell concentration of Salmonella in all the samples (Salmonella spp. ranged from <3 to 53 MPN/g;S. Enteritidis ranged from <3 to 24 MPN/g;and S. Typhimurium ranged from <3 to 15 MPN/g). The combination of the MPN-MPCR is an efficient, simple, fast analytical method for the detection and enumeration of Salmonella spp., Salmonella Enteritidis and Salmonella Typhimurium in vegetables and the vegetarian burger patties since it can significantly reduce time and labour with analysis completed within 2 days, as opposed to the traditional confirmation method that can take up to 5 days for unequivocal identification of species.

混合培养法在检测食品中沙门氏菌中的应用评价

目的通过对标准菌株以及人工污染样品的检测,评价混合培养法在检测食品中沙门氏菌的应用。方法本研究采用混合培养法对3株不同血清型的沙门氏菌和30株非沙门氏菌进行检测,分析该方法的灵敏度和特异性;同时制备人工污染的样品(包括肉制品、乳制品、巧克力)进行检测,评价混合培养法和GB 4789.4—2016《食品安全国家标准食品微生物学检验沙门氏菌检验》方法的一致性。结果混合培养法对3株沙门氏菌的检出限为1 CFU/25 g,而30株非沙门氏菌检测结果均为未检出,说明该方法具有良好的特异性;用混合培养法和GB 4789.4—2016分别对人工污染样品进行检测,对3类加标样品的检测灵敏度为:100%、100%、100%,总体灵敏度为100%;检测特异性为:93.2%、97.8%、93.2%,总体特异性为94.7%;检测假阴性率为:0、0、0,总体假阴性率为0;假阳性率为:6.8%、2.2%、6.8%,总体假阳性率为:5.3%;相对准确度为:97%、99%、97%,总体相对准确度为97.7%;混合培养法与GB 4789.4—2016方法阳性比例显著性差异为:1.33、0、1.33,总体显著性差异为0.89。结论根据SN/T 3266—2012《食品微生物检验方法确认技术规范》的判定规则,混合培养法和GB 4789.4—2016在统计学意义上无显著性差异。该方法具有提高实验效率、降低检测成本的优势,能够快速检测食品中沙门氏菌,在食品中致病性微生物的检测中具有较好的推广性。

Inactivation of Salmonella Species on New Mexico Green Chile Peppers by Flame Roasting

Salmonella spp. have been implicated in foodborne disease outbreaks involving chile peppers, usually in combination foods such as chile rellenos, salsa, pico de gallo, guacamole and others where the source of contamination is uncertain. Salmonella Typhimurium ATCC 14028 was used in this study to artificially inoculate green chile peppers. Green chile peppers were weighed and artificially contaminated by applying the calculated inoculation volumes of 4 o,L per g of pepper. No presumptive salmonellae were found on any of the peppers prior to inoculation with S. Typhimurium. Twenty inoculated chiles were transferred to a custom built lab-scale roaster and then flame roasted for five minutes until they were blistered on the surface, as is commonly at New Mexico supermarkets. The surface temperature of representative chiles was measured with an infrared thermometer. Flame roasting of green chile peppers is effective in reducing bacterial contaminants on fresh green chile peppers. Based on the TSAYE counts where inoculated chile peppers had a mean plate count of 7.21 and the roasted chile peppers 2.71 and 2.75, a 4.5 log reduction was seen. Results reveal the effectiveness of flame roasting on the microbiological safety and quality of roasted green chile peppers.

Assessment of Anti-Salmonella Activity of Aqueous and Ethanolic Extract of Senna siamae, Used in Traditional Management of Salmonellosis in Benin

Recent ethnopharmacological data cited Senna siamea as one of the most widely used medicinal plants in the management of salmonellosis in Benin. However, data related to its activity on non-typhoidal Salmonella spp are limited. This study aimed to assess the antibacterial activity of Senna siamea on multidrug-resistant Salmonella. Ethanolic and aqueous extracts of S. siamea were tested for their antibacterial activity on four multidrug-resistant Salmonella: Salmonella Typhimurium ATCC 14028 and three Salmonella spp. isolated from animals intended for human consumption in Benin. Well diffusion technique combined with the determination by microdilution of Minimum Bactericidal Concentration (MBC) and Minimum Inhibitory Concentration (MIC) were used for antibacterial testing. From antibacterial testing, inhibition diameters of the extracts ranged from 7 to 11 mm, for the susceptible strains. Colistin (reference antibiotic) was active on all Salmonella spp. with inhibition diameters between 18 and 19 mm. The MICs ranged from 3.125 to 25 mg/ml while MBCs of the extracts are greater than 100 mg/ml, so none of the extracts have antibacterial power (p.a). From these results, it appears that the use of Senna siamea in the traditional treatment of salmonellosis is justified. These results must be valued in the development of anti-salmonella phytomedicines.

噬菌体防控沙门氏菌生物被膜的研究进展

沙门氏菌是重要的食源性致病菌,控制食品中沙门氏菌的污染,特别是防止其形成生物被膜交叉污染食品,对保障食品安全具有重要意义。现阶段传统的物理性、化学性控制措施都存在一定的局限性,难以有效将沙门氏菌生物被膜完全去除,因此,亟待开发针对沙门氏菌生物被膜的新型控制和清除策略。近年来噬菌体作为一种安全、有效、无残留的天然抑菌剂受到了普遍关注,与化学消毒剂相比,其具有特异性强、自我增殖快、安全性高、研发时间短等突出优势,在食源性致病菌生物被膜的控制和清除领域已表现出巨大潜力。该文综述了沙门氏菌生物被膜的结构成分与形成过程,并重点介绍了国内外用噬菌体破解沙门氏菌生物被膜的作用机制与应用现状。针对噬菌体的未来研究方向进行了展望,以期为食品加工过程中沙门氏菌生物被膜的有效控制提供新的技术与策略。

Poor hygienic conditions of butcheries and high level of microbiological contamination of meat sold in Nampula city,Mozambique

The present study aimed to evaluate the hygiene practices and the quality of meat sold in butcheries in the city of Nampula,Mozambique.Of the twelve butcheries in the city,only seven participated in the study,which was divided into four categories:hygienic conditions of buildings and facilities,equipment,furniture and utensils,good handling practices for handlers,and microbiological quality of meat products.Results showed that most of the butcheries(71%)had poor hygiene conditions,such as walls with cracks and holes and lack of washbasins in the production area.In addition,the majority(71%)of butcheries used a reusable dirty cloth to clean equipment and utensils,and only 43%had a cold room or refrigerated chamber for meat conservation.Regarding personal hygiene,100%of the handlers washed and changed their clothes daily,but 71%did not properly wash their hands before handling food.Microbiological analysis revealed that 86%of the cutting tables swabs and 43%of the hand blades had E.coli counts above 4 Log,and the presence of Salmonella was observed in 71%of meat samples.Overall,the study highlights the need for improvement in hygiene practices and the quality of meat sold in butcheries in Nampula.

南京地区猪肉源中沙门氏菌分子分型及耐药性分析

沙门氏菌是造成我国食源性疾病的常见细菌之一,也是肉类消费过程中密切监测的重点对象。在2018年~2021年期间,共计采集了南京市545份猪肉源食品样本,利用选择性培养法分离得到44株沙门氏菌,采用血清学方法和分子生物学方法(MLST)对其进行分型鉴定,并分析其耐药性。结果表明,市售样本中共计检出44株沙门氏菌,平均检出率为8.07%,其中内脏样本检出率相对最高(检出率为30.49%);血清型分析表明,检出的菌株中以鼠伤寒沙门氏菌(Salmonella typhimurium)、罗森氏沙门氏菌(Salmonella rissen)、德尔卑沙门氏菌(Salmonella derby)和伦敦沙门氏菌(Salmonella london)4种血清型沙门氏菌最为常见;基因分型表明,ST19型为猪肉源中优势沙门氏菌株,占比为20.45%;检出的沙门氏菌中,38株菌株对四环素具有明显耐药性,占全部检出菌株的86.36%,而对头孢他啶、头孢噻肟和头孢西丁的耐药不超过10%。此外,对检出的1株多重耐药性沙门氏菌耐药基因分析发现,共筛查出了包括7大类抗生素及与耐药相关的基因。该实验详细分析了南京市场猪肉源食品中沙门氏菌污染状况,也为后期沙门氏菌的综合防治提供了理论依据。

四川省猪肉源大肠杆菌和沙门氏菌的分离与耐药性分析

采集四川省鲜猪肉126份,选择性培养基分离大肠杆菌、沙门氏菌,划线纯化后,通过形态特性及16SrDNA序列对菌株进行鉴定,利用K-B法(CLSI)药敏试验检测大肠杆菌和沙门氏菌对17种抗生素的耐药性。结果表明:共获得大肠杆菌105株,沙门氏菌18株,检出率分别为83.33%和14.28%。大肠杆菌对各种抗生素的耐药率在0%～55.3%,对四环素、氨苄西林耐药率最高,分别为55.3%、52.3%,对其他抗菌药物的耐药率依次为卡那霉素(26.7%)>链霉素(19.1%)>环丙沙星(17.1%)>诺氟沙星(14.3%)>头孢噻吩(11.5%)>氨苄西林/舒巴坦(4.8%)>头孢曲松、头孢噻肟、氨曲南、庆大霉素(2.9%)>头孢他啶(1.9%)>阿莫西林/克拉维酸(0.8%)>丁胺卡那霉素(0.1%)>亚胺培南、哌拉西林/他唑巴坦(0%),共产生28种耐药谱,氨苄西林、四环素及氨苄西林/四环素谱型占优势。沙门氏菌对各种抗生素的耐药率在0%～55.5%,其中对四环素、氨苄西林、链霉素的耐药率最高,依次是55.5%、38.9%、27.8%,对其他抗菌药物的耐药率依次是:氨苄西林/舒巴坦、阿莫西林/克拉维酸(11.1%)>头孢噻肟、卡那霉素、头孢噻吩、庆大霉素、环丙沙星、诺氟沙星(5.6%)>头孢曲松、头孢他啶、亚胺培南、氨曲南、哌拉西林/他唑巴坦、丁胺卡那霉素(0%),共产生13种耐药谱。四川省肉源大肠杆菌、沙门氏菌对各类抗生素已表现出一定的耐药性,虽耐药率相对较低,但多重耐药已经成为普遍现象,应引起足够重视,并加强对其监测。

沙门氏菌荧光实时定量PCR检测试剂的研制及应用

荧光实时定量PCR技术是近年来广泛应用于沙门氏菌快速检测的现代方法之一,本研究建立了检测沙门氏菌快速、敏感、特异以及准确定量的FQ-PCR方法。采用沙门氏菌fimY基因序列,设计特异引物和探针,通过对Taq酶、Mg2+和引物探针浓度等反应体系和条件的优化,然后进行特异性和适用性实验。最优化结果为:Taq酶用量2.5U;Mg2+浓度为3.75×10-3mol/L;引物浓度为0.65×10-6mol/L,探针浓度为0.30×10-6mol/L;循环条件为step1:95℃2min,step2:95℃5s,60℃40s,40cycles。结果表明该FQ-PCR检测试剂具有快速、简单、灵敏度高、特异性强和适用范围广等优点,可应用于食品卫生监管、商品检验检疫以及临床诊断等领域。

环介导等温扩增技术快速检测沙门菌

环介导等温扩增(1oop-mediated isothermal amplification,LAMP)是一种在等温条件下高特异、高效、快速地扩增靶序列的DNA扩增新技术。以沙门菌(Salmonellaspp.)为研究对象,根据其特异性的invA基因,设计了一套特异性引物对该基因进行了LAMP,同时优化了其反应条件,建立了沙门菌的LAMP快速检测技术。结果表明,LAMP的最佳反应条件为外引物浓度5pmol/L、内引物浓度40pmol/L,Mg2+浓度6mmol/L,dNTP浓度0.8mmol/L,甜菜碱浓度0.8mmol/L,BstDNA聚合酶8U,反应温度63℃,反应时间1h。在此条件下,LAMP检测沙门菌DNA的敏感度达10fg/反应,且与其他常见的细菌无交叉反应。其对牛奶样品的检出量为102cfu/mL,适合于食品中污染沙门菌的快速检测。

沙门菌、大肠杆菌和金黄色葡萄球菌的多重PCR检测

根据沙门菌invA基因、大肠杆菌phoA基因和金黄色葡萄球菌nuc基因序列，设计3对特异性引物进行多重PCR并对反应条件进行优化。结果表明3对引物能特异地扩增出284bp、622bp、484bp的目的条带；最佳反应条件为沙门菌、大肠杆菌、金黄色葡萄球菌的引物浓度分别为40nmol／L、40nmol／L、80nmol／L，Mg^2＋浓度2．4mmol／L，dNTP浓度2001μmol／L，Taq DNA聚合酶1.5u，退火温度55．0℃-57．4℃之间；在此条件下多重PCR同时检测DNA的敏感性分别是10．2pg、10．2pg、102．0pg，检测时间4h。建立的多重PCR是一种敏感、特异、准确、快速的方法，为同时检测食品中沙门菌、大肠杆菌和金黄色葡萄球菌奠定了基础。

畜禽肉沙门氏菌和大肠杆菌O157多重PCR检测研究

沙门氏菌和大肠杆菌O157都是目前世界公认引起食源性疾病的重要致病菌。本研究针对致病菌传统检测方法耗时长、过程繁琐的缺点,建立了同时检测畜禽肉及其制品中沙门氏菌和大肠杆菌O157的多重PCR分子检测方法。结果表明:分别针对沙门氏菌侵袭基因invA、大肠杆菌O157抗原基因rfbE建立的多重PCR方法可简便、快速、灵敏地实现对沙门氏菌和大肠杆菌O157的同时检测,整个过程在9h^10h内完成,人工污染猪肉检测限分别达到2.4×102cfu/mL(沙门氏菌)和2.2×102cfu/mL(大肠杆菌O157);为食源性致病菌的检测提供了理想手段,有良好的应用前景。

多重PCR检测食品中的金黄色葡萄球菌、志贺菌和沙门菌

目的建立一种能同时检测食品中金黄色葡萄球菌、志贺菌和沙门菌的多重PCR检测方法。方法采用7.5%NaCl肉汤对食品样品中的金黄色葡萄球菌进行增菌,同时采用GN增菌剂对食品样品中的志贺菌和沙门菌进行增菌。根据金黄色葡萄球菌的nuc基因、志贺菌的ipaH基因、沙门菌的invA基因设计引物,通过多重聚合酶链反应(PCR)反应对食品样品中上述三种病原菌的目标基因进行扩增,同时对反应体系进行优化。结果特异性实验表明本方法的特异性良好。对污染金黄色葡萄球菌、志贺菌和沙门菌的牛奶样品进行检测,检出限为1cfu/ml。结论本实验建立的多重PCR检测方法适用于食品中金黄色葡萄球菌、志贺菌和沙门菌的快速检测,具有快速、简便、灵敏的特点。