慢性根尖周炎的细菌学研究

本文对14例慢性根尖周炎患者16个感染根管细菌培养检查的结果发现:以厌氧菌为优势的混合菌感染是慢性根尖周炎感染根管细菌学的主要特点。穿髓根管由于敞开的髓腔,同一根管内4—9种细菌混合感染者占87.5％;未穿髓的感染根管2—3种细菌混合感染的占62.5％,4种以上细菌混合感染的占37.5％。优势的感染菌包括产黑色素类杆菌、口腔类杆菌、口类杆菌、具核梭杆菌、干酪乳杆菌、内氏放线菌等6种厌氧菌;血液链球菌、变链球菌和酿脓链球菌为最常见的兼性厌氧菌。本文指出口腔正常菌群是感染根管的机会病原菌。     

感染根管的厌氧菌培养结果分析

从64只感染根管中的58只根管分离到144株无芽胞厌氧菌,其中类杆菌54株,厌氧性链球菌23株,韦荣氏球菌17株,真杆菌11株,梭杆菌10株,放线菌8株,双岐杆菌2株,消化链球菌和消化球菌19株。40只根管为厌氧菌和兼性厌氧菌或需氧菌混合感染,18只根管和6只根管分别为单独厌氧菌和兼性厌氧菌感染。33只根尖周炎根管分别采集牙髓和根尖渗出物样本进行培养,实验结果表明牙髓样本中革兰氏阳性厌氧杆菌检出率较高,根尖渗出物中以产黑素类杆菌属的细菌检出率较高。根尖周炎和牙槽脓肿患者的感染根管中产黑素类杆菌属的细菌检出率明显高于蜂窝组织炎患者。     

慢性前列腺炎患者病原学必药敏试验的研究

对３００例慢性前列腺炎患者以无菌手续取得前列腺液进行需氧菌及厌氧菌培养和药敏试验,结果证明慢性前列腺炎为混合感染,其中,需氧菌主要为表皮葡萄球菌（１２０株占４０％）,其次是棒状杆菌（５２株占１７．３３％）。厌氧培养主要是痤疮丙酸杆菌（８８株占２９．３３％）。消化链球菌（７０侏占２３．３３％）,表皮葡萄球菌（５５株占１８．３３％）。因而兼性厌氧菌是该病主要的病原菌。药敏试验证明：使用时间长、频繁的抗     

40例腹部感染患者的厌氧菌分析

对我院４０例腹部感染进行了厌氧菌和需氧菌培养,结果３３例培养阳性,总检出率８２．５％,其中单纯厌氧菌和单纯需氧菌检出率,分别占阳性标本的２７．３％和３３．３％,混合阳性占３９．４％,厌氧菌中以革兰氏阴性杆菌多见６０．７％（１７／２８）,需氧菌中同样以革兰氏阴性杆菌多见６０．６％（２０／３３）,这些细菌是人体肠道内的正常菌群,提示腹部感染主要为内源性感染。     

健康青少年口腔正常菌群的初步研究

本文采用非选择性培养基对22名健康青少年的唾液、沟裂菌斑、龈上菌斑及龈下菌斑中的需氧菌、兼性厌氧菌及专性厌氧菌进行了分离培养,并计算其在不同标本中占可培养菌的百分比及检出率。结果共分离到包括18个菌属的35种细菌。其中,链球菌、放线菌、奈瑟氏球菌、二氧化碳噬纤维菌、类杆菌、梭杆菌,奴卡氏菌及棒状杆菌在口腔4个部位的检出率及所占比例均较高,是健康青少年口腔中的优势菌群.通过比较还发现,其中一些菌在口腔4个部位的分布存在一定差异.本文还采用刚果红负性染色涂片法,镜下观察龈上、龈下菌斑中的螺旋体,并计算其相对比例.结果龈下菌斑中螺旋体的相对比例明显高于龈上菌斑.     

子宫颈炎的厌氧菌培养结果分析

报告５３例子宫颈炎症患者厌氧菌和需氧菌培养,结果全部阳性,阳性率１００％,其中厌氧菌和需氧菌阳性率分别为２８．３％和１５．１％,混合阳性率５６．６％。分离出厌氧菌８５株,需氧菌５９株。前者以消化链球菌多见,占３２．９％,次为类杆菌（２８．２％）;后者以葡萄球菌具多,占２３．７％,次为链球菌和大肠埃希氏菌（１８．６％和１６．９％）。并对细菌种类和药敏试验进行了讨论。     

临床厌氧菌的分离和鉴定

我们从口腔、胸部、腹部和盆腔等处采集了110份临床感染标本,以自制的输送培养基立即送实验室,在厌氧手套箱(霍尔玛厌氧系统1029型)或Gas-pak罐中,行厌氧菌的分离和培养,其中64份标本检出厌氧菌,阳性率为58％。临床标本中牙周炎标本厌氧菌检出率高达100％,牙髓炎标本为85％,阑尾脓肿和腹膜炎标本为83％,胆道标本为39％,脓胸标本为57％,盆腔标本为33％,早期单纯性阑尾炎和甲状腺囊肿合并感染的标本各5份,都未检出厌氧菌。从64份阳性分离的标本中共分离到厌氧菌370株,经鉴定分别属于11个菌属32个菌种(未定种的有74株),其中类杆菌最多占45.9％(类杆菌属中脆弱类杆菌占37.6％),次为梭杆菌属和消化链球菌属,各占15.1％。革兰氏阳性无芽胞厌氧菌占8％左右,而梭菌属为8.9％,其余是二氧化碳噬纤维菌属(2.9％)、韦荣氏球菌属(1.3％)、链球菌属和纤毛菌属(1.5％)等。在厌氧菌鉴定中,我们使用了微量生化直接酶测定技术和代谢产物的气相色谱分析技术,这些方法在厌氧菌鉴定中比常规方法敏感且有较大的价值。     

肺切除术患者下呼吸道细菌L型培养及其临床研究

本文在５０例行肺切除术中,分别采集病肺、支气管切缘、健侧支气管内分泌物４５０份,做常规细菌和细菌Ｌ型培养及药敏试验。分离出需氧菌和真菌６０株,厌氧菌１２株、细菌Ｌ型４２株。菌群主要分布在病肺内约占５０％。需氧菌种中Ｇ＋球菌占６１．７％,葡萄球菌多见;其次Ｇ￣＋杆菌占２３．３％,以肠杆菌科细菌为主。厌氧菌占细菌型１６．７％。细菌Ｌ型特点与细菌型一致。围术期选择作用于细胞壁和细胞质的抗生素,以杀灭细菌型及细菌Ｌ型感染。     

慢性化脓性中耳炎的细菌学分析

报告７１例慢性化脓性中耳炎细菌培养和药敏试验,总阳性率９１．５％,需氧菌和厌氧菌阳性率各为６９．０％和５９．１％。其中纯需氧菌和纯厌氧菌各占３２．４％和２２．５％,需氧菌和厌氧菌混合阴性３６．６％。共检出细菌１２０株,其中以铜绿假单胞菌和厌氧消化链球菌多见。表明厌氧菌感染占有重要地位,并对感染机理,细菌分布和药敏试验进行了讨论。     

腹内感染的细菌学研究

本文对外科腹内感染150例进行了需氧与厌氧的细菌学研究。结果表明腹内感染的病原菌都是消化道内的正常菌群,需氧菌以大肠杆菌等革兰氏阴性杆菌为主,而厌氧菌则以吉氏拟杆菌等脆弱群拟杆菌多见。感染多为几种细菌的混合感染,尤其是需氧菌与厌氧菌的混合感染。并对内源性细菌引起感染的致病机理进行了讨论。     

Genome sequence of Victivallis vadensis ATCC BAA-548, an anaerobic bacterium from the phylum Lentisphaerae, isolated from the human gastrointestinal tract

Victivallis vadensis ATCC BAA-548 represents the first cultured representative from the novel phylum Lentisphaerae, a deep-branching bacterial lineage. Few cultured bacteria from this phylum are known, and V. vadensis therefore represents an important organism for evolutionary studies. V. vadensis is a strictly anaerobic sugar-fermenting isolate from the human gastrointestinal tract.     

Selective enrichment and characterization of a phosphorus-removing bacterial consortium from activated sludge

Under alternating aerobic/anaerobic conditions and without additional carbon sources, a bacterial consortium consisting initially of 18 bacterial strains was obtained in a sequence batch reactor. The phosphorus removal capability could only be maintained using sterile filtrate of activated sludge as medium. The addition of calcium and magnesium salts, as well as vitamins and trace elements, to autoclaved sterile filtrate of activated sludge was not sufficient to achieve stable phosphorus removal. A further enrichment by subcultivation on solid, agar, freezing, and shortening of the aerobic and anaerobic phases led to a defined bacterial consortium consisting of four strains. On the basis of physiological and chemotaxonomic characterization, and partial 16S rRNA sequencing, one of the organisms was identified as Delftia acidovorans. A further isolate belonged to the Bacillus cereus group, and the third isolate was identified as Microbacterium sp.. The remaining strain seems to represent a new genus within the Flavobacteriaceae. Under continuous chemostat conditions, this consortium was able to remove up to 9.6 mg P/l phosphate in the aerobic phase and released up to 8.5 mg/l in the anaerobic phase. Up to 25 mg P-polyphosphate/g dry mass was stored under aerobic conditions.     

北衙金矿矿石内部可培养细菌多样性初步研究

目的对北衙金矿矿石样品内部的可培养细菌进行分离并对其多样性进行研究。方法采集云南北衙金矿矿石样品,采用固体肉汤培养基、卵黄培养基及厌氧琼脂培养基分离矿石内部的可培养细菌,并利用16SrRNA基因序列构建系统发育树,初步评估细菌多样性。结果北衙金矿矿石内部细菌的主要种群包括厚壁菌门和放线菌门的不同菌属,包括芽孢杆菌属、类芽孢杆菌属、考克菌属及节杆菌属的菌株,其中抗逆性较强的优势菌群为放线菌门的细菌。结论本研究证实北衙金矿矿石内部的确存在大量可培羔±田萧．并且右种群名样件．     

Comparative metagenomic analysis of bacterial populations in three full-scale mesophilic anaerobic manure digesters

While the use of anaerobic digestion to generate methane as a source of bioenergy is increasing worldwide, our knowledge of the microbial communities that perform biomethanation is very limited. Using next-generation sequencing, bacterial population profiles were determined in three full-scale mesophilic anaerobic digesters operated on dairy farms in the state of Vermont (USA). To our knowledge, this is the first report of a metagenomic analysis on the bacterial population of anaerobic digesters using dairy manure as their main substrate. A total of 20,366 non-chimeric sequence reads, covering the V1-V2 hypervariable regions of the bacterial 16S rRNA gene, were assigned to 2,176 operational taxonomic units (OTUs) at a genetic distance cutoff value of 5 %. Based on their limited sequence identity to validly characterized species, the majority of OTUs identified in our study likely represented novel bacterial species. Using a naïve Bayesian classifier, 1,624 anaerobic digester OTUs could be assigned to 16 bacterial phyla, while 552 OTUs could not be classified and may belong to novel bacterial taxonomic groups that have yet to be described. Firmicutes, Bacteroidetes, and Chloroflexi were the most highly represented bacteria overall, with Bacteroidetes and Chloroflexi showing the least and the most variation in abundance between digesters, respectively. All digesters shared 132 OTUs, which as a “core” group represented 65.4 to 70.6 % of sequences in individual digesters. Our results show that bacterial populations from microbial communities of anaerobic manure digesters can display high levels of diversity despite sharing a common core substrate.     

Distinct and effective biotransformation of hexavalent chromium by a novel isolate under aerobic growth followed by facultative anaerobic incubation

A bacterial isolate (G161) with high Cr(VI)-reducing capacity was isolated from Cr(VI)-contaminated soil and identified as Leucobacter sp. on the basis of 16S rRNA gene sequence analysis. The isolate was a Gram-positive, aerobic rod. The hexavalent chromate-reducing capability of the isolate was investigated under three conditions of oxygen stress. The isolate was found to reduce Cr(VI) under all conditions but performed most effectively during aerobic growth followed by facultative anaerobic incubation. Under these conditions, the isolate tolerated K₂Cr₂O₇ concentrations up to 1,000 mg/l and completely reduced 400 mg/l K₂Cr₂O₇ within 96 h. The strain reduced Cr(VI) over a wide range of pH (6.0–11.0) and temperatures (15–45 °C) with optimum performance at pH?8.0 and 35 °C. The presence of other metals, such as Ca²⁺, Co²⁺, Cu²⁺, Mn²⁺, Ni²⁺, and Zn²⁺, induced no effect or else played a stimulatory role on Cr(VI)-reduction activity of the strain. The strain was tested for Cr(VI) removal in wastewaters and proved capable of completely reducing the contained Cr(VI). This is the novel report of a bacterial growth and Cr(VI)-reduction process under sequential aerobic growth and facultative anaerobic conditions. The study suggested that the isolate possesses a distinct capability for Cr(VI) reduction which could be harnessed for the detoxification of chromate-contaminated wastewaters.     

Microbial diversity of the brine-seawater interface of the Kebrit Deep, Red Sea, studied via 16S rRNA gene sequences and cultivation methods.

The brine-seawater interface of the Kebrit Deep, northern Red Sea, was investigated for the presence of microorganisms using phylogenetic analysis combined with cultivation methods. Under strictly anaerobic culture conditions, novel halophiles were isolated. The new rod-shaped isolates belong to the halophilic genus Halanaerobium and are the first representatives of the genus obtained from deep-sea, anaerobic brine pools. Within the genus Halanaerobium, they represent new species which grow chemoorganotrophically at NaCl concentrations ranging from 5 to 34%. The cellular fatty acid compositions are consistent with those of other Halanaerobium representatives, showing unusually large amounts of Delta7 and Delta11 16:1 fatty acids. Phylogenetic analysis of the brine-seawater interface sample revealed the presence of various bacterial 16S rRNA gene sequences dominated by cultivated members of the bacterial domain, with the majority affiliated with the genus Halanaerobium. The new Halanaerobium 16S rRNA clone sequences showed the highest similarity (99.9%) to the sequence of isolate KT-8-13 from the Kebrit Deep brine. In this initial survey, our polyphasic approach demonstrates that novel halophiles thrive in the anaerobic, deep-sea brine pool of the Kebrit Deep, Red Sea. They may contribute significantly to the anaerobic degradation of organic matter enriched at the brine-seawater interface.     

Identification and cultivation of anaerobic, syntrophic long-chain fatty acid-degrading microbes from mesophilic and thermophilic methanogenic sludges

We investigated long-chain fatty acid (LCFA)-degrading anaerobic microbes by enrichment, isolation, and RNA-based stable isotope probing (SIP). Primary enrichment cultures were made with each of four LCFA substrates (palmitate, stearate, oleate, or linoleate, as the sole energy source) at 55 degrees C or 37 degrees C with two sources of anaerobic granular sludge as the inoculum. After several transfers, we obtained seven stable enrichment cultures in which LCFAs were converted to methane. The bacterial populations in these cultures were then subjected to 16S rRNA gene-based cloning, in situ hybridization, and RNA-SIP. In five of seven enrichment cultures, the predominant bacteria were affiliated with the family Syntrophomonadaceae. The other two enrichment cultures contained different bacterial populations in which the majority of members belonged to the phylum Firmicutes and the class Deltaproteobacteria. After several attempts to isolate these dominant bacteria, strain MPA, belonging to the family Syntrophomonadaceae, and strain TOL, affiliated with the phylum Firmicutes, were successfully isolated. Strain MPA converts palmitate to acetate and methane in syntrophic association with Methanospirillum hungatei. Even though strain TOL assimilated [(13)C]palmitate in the original enrichment culture, strain TOL has not shown the ability to degrade LCFAs after isolation. These results suggest that microbes involved in the degradation of LCFAs under methanogenic conditions might not belong only to the family Syntrophomonadaceae, as most anaerobic LCFA-degrading microbes do, but may also be found in phylogenetically diverse bacterial groups.     

<Emphasis Type="Italic">Rubribacterium polymorphum</Emphasis> gen. nov., sp. nov., a novel alkaliphilic nonsulfur purple bacterium from an Eastern Siberian soda lake

An alkaliphilic nonsulfur purple bacterial (NPB) strain “Green” was isolated from sediments of the littoral zone of the soda lake (mineralization 22 g/l, pH 9.5) in the Barguzin River valley (Eastern Siberia). The cells of the new isolate are ovoid or polymorphic at latter stages. The photosynthetic membrane structures are of vesicular type. Bacteriochlorophyll a and carotenoids of both spheroidene and spirilloxanthin type are the photosynthetic pigments. Two light-harvesting systems (LH1 and LH2) are present. The new isolate is a photoheterotroph and a facultative aerobe. It grows well in the dark on organic substrates; anaerobic phototrophic growth is poor. The isolate is alkaliphilic with pH optimum of 8.5–9.5. The most abundant cell growth occurred at 5–40 g/l NaCl (optimum at 10 g/l) and 30 °C. The DNA G+C base content was 69.9 mol %. Analysis of 16S rRNA gene sequences revealed a 10% difference with the most closely related NPB (Rhodobacter species). Rubrimonas cliftoensis, a bacteriochlorophyll a-containing bacterium, is the closest relative (93.3% similarity). It is proposed that strain “Green” should be placed in the new genus and new species Rubribacterium polymorphum gen. nov., sp. nov. GenBank accession number: 16S rRNA-EU857676.     

A bioprocess for the remediation of anaerobically digested molasses spentwash from biogas plant and simultaneous production of lactic acid

A bacterial isolate LAB-1 identified as Lactobacillus casei was cultivated in a fermentation medium containing biogas plant effluent. This effluent was generated after anaerobic digestion of molasses spentwash in biogas fermenters. In the bioremediation process of this very dark coloured effluent through the cultivation of L. casei, decrease in effluent's colour of 49 and 52% and reduction in COD level up to 54 and 57% were achieved using bacterial cells in free and immobilised system, respectively, in 5 days batch cultivation. During this process of bioremediation, a metabolite lactic acid was produced by this bacterial isolate with the yield of 10.9 and 11.3 mg/ml, in free and immobilised cells fermentation, respectively.     

Biodegradation of atrazine under denitrifying conditions

Anaerobic biodegradation of atrazine by the bacterial isolate M91-3 was characterized with respect to mineralization, metabolite formation, and denitrification. The ability of the isolate to enhance atrazine biodegradation in anaerobic sediment slurries was also investigated. The organism utilized atrazine as its sole source of carbon and nitrogen under anoxic conditions in fixed-film (glass beads) batch column systems. Results of HPLC and TLC radiochromatography suggested that anaerobic biotransformation of atrazine by microbial isolate M91-3 involved hydroxyatrazine formation. Ring cleavage was demonstrated by ¹⁴CO₂ evolution. Denitrification was confirmed by detection of ¹⁵N₂ in headspace samples of K¹⁵NO₃-amended anaerobic liquid cultures. In aquatic sediments, mineralization of uniformly ring-labeled [¹⁴C]atrazine occurred in both M91-3-inoculated and uninoculated sediment. Inoculation of sediments with M91-3 did not significantly enhance anaerobic mineralization of atrazine as compared to uninoculated sediment, which suggests the presence of indigenous organisms capable of anaerobic atrazine biodegradation. Results of this study suggest that the use of M91-3 in a fixed-film bioreactor may have applications in the anaerobic removal of atrazine and nitrate from aqueous media. Received: 3 September 1997 / Received revision: 4 December 1997 / Accepted: 2 January 1998