本文選題：食源性致病菌 + 蠟樣芽孢桿菌　； 參考：《武漢輕工大學(xué)》2013年碩士論文

【摘要】：蠟樣芽孢桿菌是條件致病菌，廣泛存在于自然界，通常引起嘔吐和腹瀉兩種食物中毒。本研究，采用MPN法、鑒別培養(yǎng)基并結(jié)合ITS序列分析，檢測(cè)、分離和鑒定了138份市售大米樣品的蠟樣芽孢桿菌檢出情況。國(guó)內(nèi)134份樣品，109(81.3%)份檢出蠟樣芽孢桿菌群微生物；107份(79.9%)檢出蠟樣芽孢桿菌(含菌量為3.0～1100CFU/g)，均值39.1CFU/g；7(5.2%)份檢出蘇云金芽孢桿菌，含菌量均值3.8CFU/g；1份(0.7%)檢出蕈狀芽孢桿菌，含菌量7.2CFU/g。原料源于泰國(guó)的3份樣品中，蠟樣芽孢桿菌檢出率100%，含菌量16.9CFU/g；蘇云金芽孢桿菌檢出率66.7%，，含菌量4.7CFU/g；而越南1份樣品只檢出蘇云金芽孢桿菌，含菌量150.0CFU/g。 共分離有285株蠟樣芽孢桿菌群微生物，268株蠟樣芽胞桿菌，16株蘇云金芽孢桿菌，1株蕈狀芽孢桿菌。不同氣候區(qū)域、不同加工工藝的大米蠟樣芽孢桿菌含量有顯著差異(P0.05)。蠟樣芽孢桿菌對(duì)有利生長(zhǎng)繁殖的氣候區(qū)域有一定的選擇性。 利用PCR檢測(cè)嘔吐毒素合成相關(guān)基因ces，細(xì)胞毒素K基因cytK1、cytK2，溶血素BL基因hblC；非溶血性腸毒素基因nheB。各地區(qū)蠟樣芽孢桿菌毒素檢出率不等，在不同的氣候區(qū)域，蠟樣芽孢桿菌毒素的分布差異也極為顯著(P0.0001)。nheB(75.0%)在蠟樣芽孢桿菌中普遍存在，其次是cytK2(55.2%)和hblC(43.3%)，cytK1檢出率為零，90.3%(242/268)的菌株至少攜帶一種以上的腸毒素基因，即各地區(qū)蠟樣芽孢桿菌普遍攜帶腸毒素基因。蠟樣芽孢桿菌分離株在8℃～48℃可生長(zhǎng)。18(6.7%)株在低溫如10℃生長(zhǎng)較好，111株(41.4%)可在48℃生長(zhǎng)良好。大部分分離株(82.8%)具有β-溶血環(huán)或微弱局限溶血環(huán),也有46株(17.2%)不溶血。 16株蘇云金芽孢桿菌的ces和cytK1均為陰性，87.5%的蘇云金芽孢桿菌同時(shí)攜帶有cytK2、nheB和hblC。蕈狀芽孢桿菌毒素基因均為陰性，但具有β-溶血環(huán)。 37株(13.8%)蠟樣芽孢桿菌含有ces基因，分布在15個(gè)省市地區(qū)，比國(guó)外的蠟樣芽孢桿菌ces檢出率高許多。這些ces陽(yáng)性株攜帶腸毒素的情況是：cytK1和hblC均為陰性，只攜帶cytK2和/或nheB基因,，值得注意的是有35株(94.6%)ces和nheB同時(shí)存在，高于nheB在蠟樣芽孢桿菌分離株中的檢出率75%。多數(shù)可在10～48℃生長(zhǎng)良好。經(jīng)過(guò)HPLC-MS分析，凡含ces基因陽(yáng)性的蠟樣芽孢桿菌其嘔吐毒素cereulide也能檢出高峰值，反之，ces陰性菌株其cereulide未檢出。化學(xué)定量分析和PCR結(jié)果能互相印證。
[Abstract]:Bacillus cereus, a conditional pathogen, widely exists in nature and usually causes two kinds of food poisoning of vomiting and diarrhea. In this study, the detection, isolation and identification of Bacillus cereus in 138 market rice samples were detected by MPN method, identification medium and ITS sequence analysis. 134 samples in China and 109 (81.3%) samples were detected in wax samples. Bacillus spore microbes; 107 (79.9%) detected Bacillus cereus (3 ~ 1100CFU/g), mean value of 39.1CFU/g; 7 (5.2%) detected Bacillus thuringiensis, the mean value of Bacillus thuringiensis, 1 (0.7%) detection of Bacillus fungoides, the source of bacteria containing bacteria in 3 samples of Thailand, Bacillus cereus detection rate 100%, containing 100% The detection rate of Bacillus thuringiensis was 66.7%, the amount of bacteria was 4.7CFU/g, while that of 1 samples from Vietnam was only detected by Bacillus thuringiensis, which contained 150.0CFU/g. 16.9CFU/g
There were 285 strains of Bacillus cereus, 268 strains of Bacillus cereus, 16 Bacillus thuringiensis and 1 Bacillus mycosis. There were significant differences in the content of Bacillus cereus in different climatic regions (P0.05). Bacillus cereus had a certain selectivity for the climate regions with good growth and reproduction.
PCR was used to detect the gene CES, cytotoxin K gene cytK1, cytK2, and the hblC of the haemolysin BL gene, and the detection rate of Bacillus cereus toxin in each region of non hemolytic enterotoxin gene nheB. was different. In different climate regions, the distribution difference of Bacillus cereus toxin was also very significant (P0.0001).NheB (75%) in the wax like bud. Spores are common, followed by cytK2 (55.2%) and hblC (43.3%), cytK1 detection rate is zero, and 90.3% (242/268) strains carry at least one more enterotoxin gene. That is, Bacillus cereus generally carries the enterotoxin gene. Bacillus cereus isolates can grow.18 (6.7%) at 8 to 48 centigrade and grow better at low temperature, such as 10. 111 strains (41.4%) grew well at 48 C. Most of the isolates (82.8%) had beta hemolytic rings or weak hemolytic rings, and 46 (17.2%) did not hemolysis.
The CES and cytK1 of 16 Bacillus thuringiensis were negative, and 87.5% of Bacillus thuringiensis carried cytK2, nheB and hblC. of Bacillus funcidus were negative, but had beta hemolytic ring.
37 strains (13.8%) of Bacillus cereus contain CES gene, which are distributed in 15 provinces and regions, which are much higher than those of Bacillus cereus CES abroad. These CES positive strains carry enterotoxin, both cytK1 and hblC are negative, only cytK2 and / or nheB genes are carried, and 35 (94.6%) ces and nheB exist simultaneously, higher than nheB. The detection rate of 75%. in Bacillus cereus isolates most can grow well at 10~48 C. After HPLC-MS analysis, the high peak value of the vomit toxin cereulide of Bacillus cereus containing CES gene positive can also be detected. On the contrary, the cereulide of the CES negative strain is not detected. Chemical quantitative analysis and PCR results can confirm each other.
【學(xué)位授予單位】：武漢輕工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：R155.5

【參考文獻(xiàn)】

相關(guān)期刊論文 前5條

1 鄭景云;尹云鶴;李炳元;;中國(guó)氣候區(qū)劃新方案[J];地理學(xué)報(bào);2010年01期

2 陸水英;陳維賢;;細(xì)菌分子生物學(xué)分型技術(shù)進(jìn)展[J];國(guó)際檢驗(yàn)醫(yī)學(xué)雜志;2012年14期

3 畢宇涵;鄭曉華;薛成玉;謝平會(huì);董瑞;閆軍;遇曉杰;;米面制品蠟樣芽孢桿菌污染狀況調(diào)查[J];中國(guó)公共衛(wèi)生管理;2012年06期

4 褚小菊;;米飯中蠟樣芽孢桿菌引起食物中毒的風(fēng)險(xiǎn)分析[J];糧食與飼料工業(yè);2011年03期

5 胡堅(jiān);劉巧瑜;趙思明;;大米生產(chǎn)線上細(xì)菌和霉菌的分布特性[J];農(nóng)業(yè)機(jī)械學(xué)報(bào);2009年05期

本文編號(hào)：2028555