不同生长性能苏姜猪保育猪肠道菌群差异分析

【背景】苏姜猪是优质瘦肉型新品种猪,断奶仔猪受到多方面应激影响会出现生长性能差异。【目的】研究不同生长性能的苏姜猪保育猪肠道菌群结构的异同。【方法】试验选取了同日龄、体重相近、健康情况良好的的保育仔猪100头,在相同的饲养条件下饲养42 d,试验结束选取体重较轻的为弱仔猪,3头弱仔猪体重为18.43±2.37 kg;体重较大的为健康仔猪,3头健康仔猪体重为27.37±1.36 kg。屠宰后,采集其空肠和盲肠内容物,提取微生物基因组DNA进行高通量测序分析其菌群结构。【结果】苏姜猪仔猪空肠和盲肠在菌群丰度、多样性上有极显著的差异(P<0.01)。苏姜猪仔猪空肠菌群优势菌群为变形菌门(Proteobacteria)假单胞菌属(Pseudomonas)的非致病性菌株,占比超过90%。苏姜猪仔猪盲肠优势菌门依次为拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)。门水平组成结构存在差异,弱仔猪厚壁菌门丰度低于健康仔猪、变形菌门丰度高于健康仔猪。苏姜猪盲肠中普雷沃氏菌属(Prevotella)、疣微菌科UCG-005 (Ruminococcaceae_UCG-005)、拟普雷沃菌属(Alloprevotella)等与纤维消化有关的菌属丰度较高。弱仔猪与健康仔猪盲肠菌群在属水平结构存在显著差异(P<0.05),弱仔猪盲肠中普雷沃氏菌-9 (Prevotella_9)、埃希菌-志贺菌属(Escherichia-shigella)、疣微菌科UCG-005 (Ruminococcaceae_UCG-005)、Norank_f_普雷沃氏菌(norank_f_ Prevotellaceae)高于健康仔猪,健康仔猪盲肠中乳酸杆菌属(Lactobacillus)、普雷沃氏菌-2 (Prevotella_2)、土孢杆菌属(Terrisporobacter)、狭义梭菌属1 (Clostridium_sensu_stricto_1)高于弱仔猪。其中乳酸杆菌属和土孢杆菌属与仔猪健康相关,埃希菌-志贺菌属与疾病相关。【结论】不同生长性能仔猪肠道菌群构成存在显著差异,研究结果为进一步研究苏姜猪肠道菌群的功能提供依据。     

基于16S rDNA扩增子测序技术揭示真胃左方变位对奶牛粪便微生物的影响

【目的】本试验旨在测定产后健康奶牛和罹患真胃左方变位(left displacement of the abomasum,LDA)奶牛粪便中微生物菌群的变化,以期探讨LDA发生与菌群的关联性,评估其对机体代谢的潜在影响。【方法】采用16S rDNA高通量测序技术,测定10头健康奶牛(Health)、10头真胃左方变位奶牛(LDA)粪便中微生物16SrDNAV3–V4区序列,并对菌群群落结构和多样性进行比较,分析其与LDA发生的相关性。【结果】多样性分析表明,Health组与LDA组奶牛的粪便中微生物多样性和群落组成存在较大的差异,其中LDA奶牛粪便微生物具有较高的物种丰度和种群差异性。对门、科、属3个分类水平上最大丰度排名前10的物种进行分析发现,LDA奶牛疣微菌门、蓝菌门、变形菌门、梭杆菌门、拟杆菌科、p-2534-18B5菌科、艰难杆菌科、梭杆菌科、螺旋菌属、5-7N15菌属和梭杆菌属的丰度显著升高(P<0.05),而螺旋体门、TM7菌门、瘤胃球菌科、理研菌科、密螺旋体属的丰度显著下降(P<0.05)。功能预测分析表明,LDA奶牛碳水化合物代谢和脂质代谢通路相关功能基因显著上调,而遗传信息处理相关功能基因显著下调。【结论】本试验研究了健康奶牛和LDA奶牛粪便微生物的变化,为LDA的致病机理、早期诊断提供了理论依据与研究基础。     

规模化牛场犊牛直肠细菌多样性分析

【目的】研究腹泻犊牛直肠细菌多样性,以及与健康犊牛直肠细菌多样性的差异。【方法】通过建立直肠菌群16S rRNA基因克隆文库,分别用限制性内切酶MspⅠ和HhaⅠ对阳性克隆的PCR产物进行限制性酶切片段长度多态性(RFLP)分析,通过测定16S rRNA基因序列,绘制系统发育树,确定犊牛直肠菌群的组成。【结果】腹泻组克隆阳性率达98.75%(474/480),优势菌群以乳杆菌属(14%)、肠球菌属(10%)和埃希菌属(8%)等需氧和兼性厌氧菌为主,健康组克隆阳性率达96.45%(488/506),优势菌群以梭菌属(13%)、双歧杆菌属(8%)和巨型球菌属(5%)等专性厌氧菌为主。【结论】2周龄犊牛直肠菌群复杂多样,并且具有自己的独特性菌群,且腹泻时乳杆菌属、肠球菌属、埃希氏菌属等显著增加。     

应用PCR-DGGE和Real-Time PCR分析健康与腹泻獭兔盲肠菌群

【目的】研究獭兔腹泻发生后盲肠菌群结构的变化情况,为微生态防治断奶兔腹泻提供理论基础。【方法】分别提取5只健康和腹泻獭兔盲肠内容物总DNA,应用PCR-DGGE及Real-Time PCR技术比较分析獭兔盲肠中菌群结构的差异。【结果】腹泻獭兔PCR-DGGE图谱条带丰富度、均匀度、多样性指数与健康獭兔相比差异均不显著,但聚类分析和主成分分析(PCA)能够将腹泻组和健康组区分开。Real-Time PCR检测显示,腹泻獭兔盲肠正常菌群普雷沃氏菌、梭菌类群Ⅰ数量与健康獭兔相比没有变化(P0.05);链球菌属、梭菌类群Ⅳ和ⅩⅣa、白色瘤胃球菌、溶纤维丁酸弧菌、普拉梭杆菌等有益微生物数量显著降低(P0.01),而埃希氏大肠杆菌数量却显著升高(P0.05)。【结论】獭兔腹泻发生后盲肠有益微生物数量降低,有害微生物数量升高;菌群结构有差异但不显著(P0.05),腹泻獭兔盲肠菌群结构有复杂化的趋势。     

~(137)Cs辐照对橘小实蝇雄虫肠道菌群多样性的影响

【目的】为研究137Cs辐照前后橘小实蝇雄虫肠道菌群多样性和丰度的变化及其肠道菌群在不同分类阶元上的显著差异物种。【方法】本研究利用IlluminaHiSeq高通量测序技术对辐照组和对照组共6个样品进行测序分析。【结果】变形菌门和厚壁菌门分别以60.38%、24.33%的比例作为橘小实蝇肠道中的优势菌门和次优势菌门,肠杆菌科和肠球菌科分别以60.38%和15.69%作为优势菌科和次优势菌科。米勒氏菌属(Moellerella)、摩根氏菌属(Morganella)、Cosenzaea属、链球菌科未知属和酸热菌属(Acidothermus)是组间显著差异的菌属。【结论】本研究发现橘小实蝇在辐照后的肠道菌群多样性和丰度均有显著性降低,并在目至属等3个分类阶元上找到辐照后具有显著差异的物种,为后期利用差异菌群来改善辐照对橘小实蝇的消极影响及修复辐照损伤提供理论基础。     

七氟菊酯和溴氰菊酯对棉铃虫肠道菌群的影响

【目的】本研究旨在探究拟除虫菊酯类杀虫剂对棉铃虫Helicoverpa armigera幼虫肠道菌群结构及代谢的影响,丰富对杀虫剂作用机理的认识。【方法】分别对棉铃虫2和3龄幼虫饲喂普通人工饲料(对照组, SS)、含2%七氟菊酯(Ⅰ型拟除虫菊酯)粉剂饲料(七氟菊酯处理组,Te)和含2.5%溴氰菊酯(Ⅱ型拟除虫菊酯)乳油饲料(溴氰菊酯处理组, DM),然后提取3龄幼虫肠道菌群基因组DNA;利用Illumina MiSeq二代高通量测序技术对肠道细菌的16S rDNA的V3-V4变异区进行测序,分析其肠道细菌的多样性和丰富度;利用qPCR验证16S rDNA测序分析结果。取2和3龄幼虫肠道,匀浆后进行Biolog-Eco实验,分析肠道细菌对Eco板上31种碳源的代谢情况。【结果】16S rDNA测序结果表明,棉铃虫3龄幼虫肠道细菌主要是厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)和蓝藻菌门(Cyanobacteria)。与对照组相比,溴氰菊酯处理组和七氟菊酯处理组的棉铃虫幼虫肠道细菌的α多样性指数没有显著性改变,但是菌群结构发生了变化：在门水平,拟杆菌门的相对丰度减少,厚壁菌门和蓝藻菌门的相对丰度增加,qPCR验证结果亦支持16S rDNA测序分析的这个结果;在属水平,拟杆菌属Bacteroides、普氏菌属Prevotella和假单胞菌属Pseudomonas等的相对丰度降低,狭义梭菌属Clostridium sensu stricto 1、埃希菌属-志贺氏菌属Escherichia-Shigella和盐单胞菌属Halomonas等的相对丰度增加,其中盐单胞菌属Halomonas的相对丰度显著增加。Biolog-Eco结果表明,与对照组相比,溴氰菊酯处理组中2龄幼虫对羧酸类碳源的代谢能力下降;溴氰菊酯处理组和七氟菊酯处理组中3龄幼虫对DL-α-磷酸甘油、肝糖和L-苯丙氨酸等碳源的利用能力下降。【结论】结果显示,拟除虫菊酯类杀虫剂对棉铃虫肠道菌群的结构和代谢能力有明显影响,拟除虫菊酯类杀虫剂使棉铃虫肠道有益菌的相对丰度下降,而使致病菌的相对丰度增加。短时间拟除虫菊酯处理未造成抗药性菌群的丰度增加。qPCR检测结果与16S rDNA测序分析结果相似。Ⅰ型和Ⅱ型拟除虫菊酯类杀虫剂对棉铃虫肠道菌群结构和代谢功能的影响不同。     

基于高通量测序的不同虫态洋虫内共生微生物群落分析

【目的】为分析不同虫态下洋虫内共生微生物菌群组成情况,以成虫和幼虫两种虫态为研究对象。【方法】通过对洋虫内共生微生物提取及高通量测序分析,获得不同样品中微生物组成结构及变化情况。【结果】不同虫态下,随着生长发育的进行,洋虫体内细菌在丰度和多样性两个方面都有很大变化,成虫中的菌群数量相对较少,多样性较幼虫也明显降低。在几种特定微生物组成上不同虫态也存在着较大的差异,成虫中,漫游球菌属和乳酸菌菌属为优势菌属;幼虫体内乳酸菌菌属为优势菌属。真菌变化不明显,孢囊线黑粉酵母菌属为其优势菌属。【结论】研究结果将为后继洋虫生物资源的研究提供相关信息,为洋虫内共生微生物资源开发与利用提供理论依据。     

黄粉虫及其肠道微生物对聚氯乙烯的生物降解作用

【背景】塑料废物的累积是越来越严重的环境污染问题,其中聚氯乙烯(polyvinyl chloride,PVC)作为最常用的塑料之一,其生产与消耗量极大。【目的】基于黄粉虫(Tenebriomolitor)幼虫自然取食塑料的现象,探究黄粉虫及其肠道微生物对聚氯乙烯类塑料的生物降解作用。【方法】通过观测黄粉虫取食聚氯乙烯过程的重量变化、傅里叶变换红外光谱(fouriertransforminfrared spectroscopy,FTIR)、黄粉虫肠道微生物的筛选和高通量测序等方法研究黄粉虫幼虫及其肠道微生物对聚氯乙烯的降解作用。【结果】研究结果表明:仅以PVC作为碳源类营养来源,每200条黄粉虫为一组,共3组,喂养32d后,每组平均取食了0.499±0.023gPVC,黄粉虫平均体重增长0.015±0.002 g。采用傅里叶变换红外光谱检测发现虫粪组分中PVC官能团中的C-C骨架峰明显减弱,表明PVC长链有断裂现象。高通量测序黄粉虫幼虫肠道微生物菌群的结果显示肠道菌群以哈夫尼菌属(Hafnia)、摩根氏菌属(Morganella)、大肠埃希氏杆菌属(Escherichia coli)和未培养肠杆菌属(unclassifiedEnterobacteriaceae)为优势菌群。肠道菌群中哈夫尼菌属(Hafnia)和摩根氏菌属(Morganella)的丰度分别比常规饲养对照增加了35.20%和16.42%。【结论】证明了黄粉虫及其肠道微生物对PVC塑料具有一定的降解作用,且其肠道菌群中哈夫尼菌属(Hafnia)和摩根氏菌属(Morganella)菌株对PVC的利用效率最高,研究结果为"白色污染"的生物降解提供了科学证据。     

16S rRNA基因高通量测序方法检测奶牛场常用干草表面微生物群落结构及多样性

【目的】随着中国奶牛业的发展,干草需求量与日俱增。作为天然牧草,干草可以成为家畜传播病原体的载体。以干草表面附着物为研究对象,了解干草中细菌群落结构以及致病菌属特征。【方法】对来自6个不同奶牛场饲草舍的干草样本,应用Illumina Mi Seq高通量测序技术测定干草表面附着物细菌的16S r RNA基因V3-V4变异区序列,分析不同干草样本细菌群落组成。【结果】干草样本中的细菌在97%的相似水平下共得到OTU个数为15 416,涵盖了29门87纲144目219科323属的细菌。微生物多样性分析表明,干草样本具有很高的细菌多样性,不同样本多样性存在差异。对干草样本菌群中丰度较高的14种病原菌属进行分析,发现相较于人工种植牧草制备的干草,天然牧草制备的干草中病原菌属丰度较高。【结论】研究解析了干草样本中微生物的多样性、丰度及主要病原菌属的特征,对奶牛场疾病防控有一定指导意义。     

吸烟对健康人群唾液微生物组的影响

【背景】吸烟是重要的公共健康问题,可能通过改变唾液微生物组影响口腔健康甚至全身健康。【目的】探究吸烟对中国健康人群唾液微生物组的影响,为研究吸烟在疾病发展中的作用提供线索。【方法】收集167位健康个体的唾液样本,利用HiSeq高通量测序技术对样品中16S rRNA基因V3-V4区进行测序,分析比较吸烟者和非吸烟者的唾液微生物组的多样性、群落结构和物种丰度,并预测功能组成,探究吸烟对唾液微生物组的影响。【结果】吸烟对唾液微生物组的α多样性影响较小,但是在微生物组组成上,吸烟组中奈瑟菌属、艾肯菌属、二氧化碳嗜纤维属等细菌明显减少,而普雷沃氏菌属、韦荣氏球菌属、放线菌属、奇异菌属和巨球型菌属等细菌明显增加。在功能上,PICRUSt的预测结果显示吸烟组富集不依赖氧气的代谢功能,非吸烟组富集需要氧气参与的代谢功能。【结论】吸烟可能会通过改变唾液微生物组,造成微生物组功能途径的变化,进而引发与吸烟相关的疾病。     

IgA肾病与膜性肾病患者肠道微生物菌群结构分析

【背景】越来越多的证据表明肠道失衡与免疫介导的疾病相关,但肠道菌群和免疫介导的肾脏疾病之间的关系仍不清楚。【目的】通过Illumina高通量测序方法对IgA肾病(immunoglobulin A nephropathy, IgAN)、膜性肾病(membranous nephropathy, MN)患者和健康人群的肠道菌群进行比较。【方法】回顾性选择2020年9月–2021年12月期间,在甘肃省人民医院肾内科行肾穿刺活检并诊断为IgAN及MN患者的新鲜粪便标本,分别编号为IgAN组和MN组,收集体检中心健康人群粪便标本作为健康对照组,每组样本为10例。采用高通量测序技术对粪便样本中所有细菌的16S rRNA基因V3-V4区进行DNA测序,然后进行分类操作单元(operational taxonomic units, OTU)、物种分类、α多样性、β多样性等分析,比较3组之间的肠道菌群差异。【结果】与健康对照组相比,门水平上IgAN组的变形菌门(Proteobacteria)和放线菌门(Actinobacteria)比例明显增高,分别为18%vs. 4%和18.3%vs. 5%;属水平上I...     

The effects of implementing management practices on somatic cell count levels in bovine milk

Somatic cell count (SCC) can be used as a proxy for the prevalence of mastitis in a herd, reflecting the hygiene conditions and management practices on dairy farms, and thus an indicator of milk quality. In this study, we investigated how the adoption of management practices in milking systems can contribute to the reduction of SCC levels and improve milk quality. We collected data regarding management practices from 91 dairy farms in three municipalities of southeastern Pará: Parauapebas, Curionópolis, and Eldorado dos Carajás. Fifty milliliters of milk from each farm were collected in bottles containing bronopol, to preserve SCC. An exploratory factorial analysis (EFA) was performed to reduce the number of variables (management techniques) on dairy farms to some latent factors. We then used the selected factors to estimate the bovine mastitis management index to classify farms according to their use of technology and management techniques. Our results showed that most of the farmers (65.9%) used management techniques inefficiently in their systems, resulting in a significant loss of product quality, while only 3.3% had adopted the full set of techniques. The EFA results demonstrated that simple management practices including regular cleaning of the milking lines, a strip cup test, the California mastitis test, and washing teats with water before milking could be adopted to improve milk quality. However, in scenarios where the regulations become more rigorous, most farmers are unable to meet the maximum allowable SCC requirements, necessitating management innovations to reduce SCC. Therefore, the dissemination of knowledge, technical assistance, and access to new technologies is essential for improving management practices, and thus milk quality.     

Changes in bovine milk bacterial microbiome from healthy and subclinical mastitis affected animals of the Girolando,Gyr, Guzera,and Holstein breeds

Raw milk samples were collected from 200 dairy cows belonging to Girolando 1/2, Gyr, Guzera, and Holstein breeds, and the bacterial diversity was explored using 16S rRNA amplicon sequencing. SCC analysis showed that 69 animals were classified as affected with subclinical mastitis. The milk bacterial microbiome was dominated by Firmicutes, Proteobacteria, and Actinobacteria, with an increase of Firmicutes in animals with subclinical mastitis and Proteobacteria in healthy animals. At the family and genus level, the milk bacterial microbiome was dominated by Staphylococcus, Acinetobacter, Pseudomonas, members of the family Enterobacteriaceae, Lactococcus, Aerococcus, members of the family Rhizobiaceae, Anaerobacillus, Streptococcus, members of the family Intrasporangiaceae, members of the family Planococcaceae, Corynebacterium, Nocardioides, and Chryseobacterium. Significant differences in alpha and beta diversity analysis suggest an effect of udder health status and breed on the composition of raw bovine milk microbiota. LEfSe analysis showed 45 and 51 discriminative taxonomic biomarkers associated with udder health status and with one of the four breeds respectively, suggesting an effect of subclinical mastitis and breed on the microbiota of milk in cattle.

     

耐碳青霉烯类肺炎克雷伯菌对C57BL/6小鼠肺部菌群的扰动

【背景】肺部菌群与宿主健康和呼吸道疾病密切相关,耐碳青霉烯类肺炎克雷伯菌(carbapenem-resistantKlebsiella pneumonia,CRKP)是临床常见的条件致病菌,感染后对肺部菌群的影响尚不清楚。【目的】探究耐碳青霉烯类肺炎克雷伯杆菌CRKP2对C57BL/6小鼠肺部菌群的扰动。【方法】将C57BL/6小鼠随机分为3组,分别用CRKP2、碳青霉烯类敏感肺炎克雷伯菌KP2044和无菌PBS溶液滴鼻,利用16S rRNA基因的高通量测序技术分析肺部菌群结构。【结果】与健康小鼠相比,菌株KP2044和CRKP2感染后小鼠肺部菌群α多样性和β多样性均显著改变,变形菌门相对丰度显著增加,乳酸杆菌属相对丰度明显下降。与KP2044相比,CRKP2生物膜形成能力较弱,感染后小鼠死亡率较低,对肺部菌群的扰动较小。【结论】虽然肺炎克雷伯菌是条件致病菌,但高剂量耐碳青霉烯类肺炎克雷伯菌CRKP2仍对健康小鼠肺部菌群造成显著影响;尽管菌株CRKP2具有多重耐药性,但与菌株KP2044相比对肺部菌群的扰动较小,因此推测KP菌株感染对肺部菌群的扰动程度可能与菌株毒力有关。     

Genetic diversity and population structure of <Emphasis Type="Italic">Escherichia coli</Emphasis> from neighboring small-scale dairy farms

The genetic diversity and population structure of Escherichia coli isolates from small-scale dairy farms were used to assess the ability of E. coli to spread within the farm environment and between neighboring farms. A total of 164 E. coli isolates were obtained from bovine feces, bedding, cow teats and milk from 6 small-scale dairy farms. Ward’s clustering grouped the isolates into 54 different random amplified polymorphic DNA (RAPD) types at 95% similarity, regardless of either the sample type or the farm of isolation. This suggests that RAPD types are shared between bovine feces, bedding, cow teats, and milk. In addition, transmission of RAPD types between the studied farms was suggested by the Ward grouping pattern of the isolates, Nei’s and AMOVA population analyses, and genetic landscape shape analysis. For the first time, the latter analytical tool was used to assess the ability of E. coli to disseminate between small-scale dairy farms within the same producing region. Although a number of dispersal mechanisms could exist between farms, the genetic landscape shape analysis associated the flow of E. coli RAPD types with the movement of forage and milking staff between farms. This study will aid in planning disease prevention strategies and optimizing husbandry practices.     

Prevalence of Prototheca spp. on dairy farms in Poland – a cross-country study

The Prototheca algae have recently emerged as an important cause of bovine mastitis globally. Here, we present results of a first large-scale, cross-country survey on the prevalence of Prototheca spp. in dairy cows, and their environment in Poland. A total of 1211 samples were collected and microbiologically analysed. Included within this number were milk (n = 638), body swabs (n = 374) and environmental samples (n = 199), originating from 400 dairy cows and their surroundings, on 16 dairy farms, based in all major provinces of the country. Prototheca spp. were the third, after Streptococcus and Staphylococcus spp., most common mastitis pathogens. The overall prevalence of protothecal mastitis was 8.3% (33/400), with the majority (75.8%) of cases having a subclinical course, and all but one attributable to P. zopfii genotype 2. Prototheca spp. were cultured from body swabs of both healthy and mastitic cows, yet the isolation rate among the latter was conspicuously lower (12.3% vs. 17.8%). Forty-two (21.2%) environmental samples yielded growth of Prototheca spp. However, no clear association between Prototheca mastitis in dairy cows and the algal isolation from the herd environment was found. Nor was there any association between the environmental recovery of the algae and farm management practices.     

Whole-genome analysis of Klebsiella pneumoniae from bovine mastitis milk in the U.S.

Dairy cattle mastitis has long been one of the most common and costly diseases in the dairy industry worldwide, due to its significant impact on milk production and animal welfare. Among all mastitis causing bacterial pathogens, Klebsiella pneumoniae causes the largest milk loss. To better understand the genomic features of this population, 180 K. pneumoniae strains isolated from dairy cattle mastitis milk in 11 U.S. states were sequenced. The phylogenetic analysis classified all mastitis-causing K. pneumoniae into two major phylogroups, with exclusive predominance in phylogroup KpI. Analysis of more than 61 sequence types, 51 capsular types and 12 lipopolysaccharide O-antigen types revealed great genomic diversity of this K. pneumoniae population. Approximately 100 gene units in accessory genomes were detected with significantly higher prevalence in bovine mastitis strains, compared to human-sourced or dairy environmental strains. The most notable genes were identified associated with ferric citrate uptake, lactose fermentation and resistance to heavy metals. The acquired antimicrobial resistance genes were identified in sporadic mastitis strains. This comprehensive genomic epidemiological study provides insights for a better understanding of the virulence of mastitis-causing K. pneumoniae strains and may lead to the development of novel diagnostic tools and preventive strategies.     

患子宫内膜炎母猪产道致病菌谱分析及卟啉单胞菌的分离鉴定

【背景】子宫内膜炎是规模化养殖场母猪常患的生殖道疾病之一,对养殖业造成的经济损失较大,细菌感染是常见的病因之一,但具体病原及致病机制尚未完全明确。【目的】探究产道菌群对母猪子宫内膜炎的影响。【方法】采用第三代细菌16S rRNA基因全长高通量测序技术进行对比,研究健康和患有子宫内膜炎母猪产道菌群差异,并依据菌群分析结果对子宫内膜炎母猪产道分泌物进行细菌分离。建立荧光定量PCR计数方法测定母猪产道样品中的卟啉单胞菌数。【结果】健康和患子宫内膜炎母猪产道菌群的丰富度和多样性差异显著;与健康组母猪相比,患子宫内膜炎母猪产道菌群变形菌门(Proteobacteria)、拟杆菌门相对丰度显著增加(P<0.05)。在属分类水平上,健康母猪产道的主要优势菌属为金黄杆菌属、芽孢杆菌属、毛螺菌属等,这些优势属在患子宫内膜炎母猪产道丰度降低,患子宫内膜炎母猪产道丰度最高的菌属为埃希氏菌属(Escherichia)、Rodentibacter和卟啉单胞菌属(Porphyromonas)。在种水平上,Porphyromonas somerae是患子宫内膜炎母猪产道的主要条件性致病菌。依据菌群分析结果,本研究从子宫内膜炎母猪产道分泌物中分离到一株卟啉单胞菌,经鉴定该菌16S rRNA基因与Porphyromonas somerae DSM 23386 strain JCM 13867(NR_113090.1)相似性达99.04%。荧光定量PCR计数方法测定,子宫内膜炎母猪产道卟啉单胞菌数量显著高于健康母猪(P<0.05),推测卟啉单胞菌与该批次母猪子宫内膜炎病因有关。【结论】本研究为子宫内膜炎母猪的病因和发病机制奠定基础,并为其治疗提供理论依据。     

Microbiological quality of raw milk produced in Estonia

Aims: The microbial quality of farm bulk‐tank raw milk produced in Estonia during years 2004–2007 was investigated. Methods and Results: Bulk‐tank milk samples were analysed for lactic acid bacteria count (LABC), psychrotrophic bacteria count (PBC), aerobic spore‐forming bacteria count (ASFBC), total bacterial counts using BactoScan and somatic cell count (SCC) using Fossomatic. Randomly selected psychrotrophic isolates were subjected to 16S–23S PCR‐ribotyping. LABC remained below 10⁴ CFU ml^?1 in most samples, while psychrotrophic micro‐organisms dominated in 60% of farms. PBC ranged from 4·2 × 10² to 6·4 × 10⁴ CFU ml^?1, and ASFBC varied from 5 to 836 CFU ml^?1. Conclusions: In general, the microbiological quality of the farm bulk‐tank milk was good – more than 91% of samples contained <50 000 CFU ml^?1, and SCC in the majority of samples did not exceed the internationally recommended limits. Genus Pseudomonas spp. was the dominating spoilage flora with Pseudomonas fluorescens as the prevailing species. Significance and Impact of the Study: Specific bacterial groups (LABC, PBC and ASFBC), not analysed routinely by dairies, were determined in bulk‐tank raw milk of numerous dairy farms during 4‐year period. Based on the survey, dairy plants can better control their supply chains and select farms (milk) for the production of specific products, i.e. milk with low PBC and high LABC for cheesemaking.