肺炎杆菌质粒图谱的研究与分析

本文对临床分离的８９株肺炎杆菌进行了７种抗生素敏感性检测以及质粒图谱分析。结果,９１．２％的菌株均对２种或２种以上抗生素耐药,并呈９个型别的耐药谱。全部被检菌株共分１６种质粒图谱,其中主要为ＰＰⅠ、ＰＰⅡ、ＰＰⅢ、ＰＰⅣ及ＰＰⅤ。这５种主要质粒图谱型别所包含的５６株菌株中,９４．６％的菌株具有共同稳定相似的耐药谱,即耐羧苄青霉素、氨苄青霉素及灭滴灵。另外７６株检出质粒的菌株中,９１．７％的菌株含有分子量１２６×１０￣６的大质粒。     

肾移植术后抗生素预防性使用与绿脓杆菌的定植及感染

本文就肾移植术后的预防性抗生素使用与控制咽部绿脓杆菌的定值及其感染作了前瞻性研究。36例上述病人分为常规抗生素治疗和改进治疗两组各18人。肾移植术后常规治疗组病人咽部定植绿脓杆菌的16人(88.89%),发生绿脓杆菌继发感染的7人,感染率为38.89%。改进治疗组中,18例病人咽部定植绿脓杆菌的5人(27.78%),发生感染的1人,感染率为5.56%,此组患者感染明显低于常规治疗组(P<0.05)。绿脓杆菌的血清型83.15%为第四群6型。质粒分析表明咽部定植绿脓杆菌的同感染灶上的绿脓杆菌具有相同的质粒图谱。作者认为:肾移植术后预防性使用抗生素可以有效地预防术后感染,但必须控制抗生素的疗程和剂量,否则将会导致机体正常菌群微生态平衡失调,耐药性绿脓杆菌定植于局部,极易造成感染的爆发.     

几类快生型根瘤菌质粒的研究

用一种重现性好而较简便的方法,对国内的紫云英、豌豆、三叶草、大豆等快生型根瘤菌及根癌农杆菌共40多号菌进行了质粒分离,所得质粒图谱具有一定的菌株特异性。每株菌有1—3个质粒,其中至少有一个大质粒或巨大质粒。用质粒消除法获得失去结瘤(或致癌)能力的变异株,均缺少一个大质粒。快生型根瘤菌的结瘤基因定位在大质粒或巨大质粒上。用接合法将Rpl：：Tn501等质粒转入根瘤菌中,能诱动根瘤菌的结瘤基因转移给失去结瘤能力的变异株,可表达功能,质粒图谱也发生变化,与供体或受体都不同。     

玉米线立体类质粒的克隆和鉴定

S型细胞质雄性不育玉米的线粒体类质粒S-1为一个长6.4kb的双链线状DNA分子。本文对基本上全长的S-1（只用限制内切酶PstI在两端各切掉128bp）在pUC18和pBR322两种质粒中进行了克隆得到4种杂合的质粒。限制性酶切图谱证明它们分别是S-1以不同方向克隆在两种质粒中的结果,Southern印迹杂交也证明S-1克隆在pBR322中.     

广州地区淋球菌抗生素耐药性及质粒图谱研究

目的：了解广州地区淋球菌对抗生素的耐药性及质粒图谱。方法：用琼脂稀释法测定5种抗生素对167株菌的最低抑菌浓度（MIC）及用破裂解法分析160株菌的质粒图谱。结果：167株淋球菌检出PPN9株（5．4％）,TRNG16株（9．6％）,环丙沙星耐药率达78．4％,头孢三嗪,壮观霉素未发现耐药菌株。160株菌其质粒谱型2．6Md 4.5Md(24.4%),2.6Md 4.5Md 24.5Md(20.6%),2.6Md 24.5Md(20.6%),4.5Md检出率（45％）24.5Md检出率（41．3％）。结论：表明了广州地区淋球菌抗生素的耐药性和质粒图谱,有助于淋病的治疗和防治。     

志贺菌流行株药物敏感性及质粒图谱分析

目的：分析志贺菌流行株的质粒图谱及其与细菌药物敏感性的相关性。方法：从菌痢患者粪便标本中分离6株 福氏志力和4株宋内志贺菌,分别对其质粒图谱与药物敏感性进行检测和对其相关性进行分析。结果：不同菌株的质粒图谱具有明显的差异,各菌株的质粒图谱与其对头孢三嗪、头孢唑林、环丙沙星、诺氟沙星、氯霉素的耐药特性无明显相关性。结论：获自患者的福氏志贺菌和宋内志贺菌具有不同的质粒图谱以及抗菌药物敏感性,提示在我市引起菌痢的志贺菌具有不同的来源。     

TGFα-PE 40的基因克隆、表达和对人癌细胞生长的抑制作用

本文报告了构建人转化生长因子α和绿脓杆菌外毒素融合基因的表达型重组质粒pYX382和pYX 3825,两种质粒转化大肠杆菌BL21后,经IPTG 诱导,表达融合蛋白TGFα-PE 40,表达产物分子量为46 kd,具有和抗TGF a抗体和抗PE 抗体反应的能力,重组质粒pYX 3825带有信号肽顺序,因而在细菌中表达产物大部分被分泌到培基和周质中。TGFa-PE 40具有和细胞表面EGFR 结合的能力,因而,能与过度表达EGFR 的癌细胞结合,将毒素蛋白的活性部分带入细胞而显示对癌细胞蛋白质合成的强烈抑制和对癌细胞的杀伤。     

斑点热群立克次体的PCR／SSCP分型技术研究

本文应用PCR／SSCP技术对斑点热群立克次体国际标准株、国内各参考株及黑龙江立克农作54株、36株进行了分型鉴定。结果显示各株之间SSCP图谱差异明显,国内各参考株的SSCP,图谱与西伯利亚立克次体的图谱完全一致,黑龙江立克次作的图谱与国内各株显著不同。分析表明,我国存在2种斑点热群立克次体,即西伯利亚立克农作种和斑点热群立克次体新种－黑龙江立克次体。同时证明应用PCP／SSCP技术分析斑点热群立克农作型别,具有方法简单、经济省时、结果准确等优点。该分型技术应用于立克次体分型国内外未见报道。     

MRSA感染的血清学分型及质粒研究

探明MRSA感染的血清学特点及质粒分布 ,为其预防和治疗提供科学依据。做血浆凝固抑制试验—中和法和质粒DNA提取用碱裂解法。结果血浆凝固酶Ⅱ型的检出阳性率为 5 4.0 % ( 47/ 87) ,Ⅳ型为 2 7.5 % ( 2 4/ 87) ,其余为Ⅶ和Ⅲ型。按菌株来源分析 :病房工作人员和住院患者的MRSA以Ⅱ型居多 ,Ⅳ型次之 ,有明显的偏重集中趋势 ,而门诊患者MRSA血浆凝固酶型别分布散乱。多数菌株有质粒 ,分布复杂。表明沈阳地区流行的主要血浆凝固酶型别为Ⅱ型和Ⅳ型。     

绿脓杆菌OMP图谱分析

绿脓杆菌ＯＭＰ图谱分析哈尔滨医科大学哈尔滨１５００８６郭晓奎,马佳毓,张丽娟佳木斯医学院佳木斯１５４００２杨景云绿脓杆菌是引起院内感染的主要条件致病菌之一,对多种抗生素不敏感,有“天然耐药菌”之称。其感染症的防治十分困难。因此,绿脓杆菌流行病学研究十...     

Characterization of Salmonella virchow phage types by plasmid profile and IS200 distribution

The type strains of the 57 phage types of Salmonella virchow have been characterized by plasmid profile and by distribution of the insertion sequence IS 200 . Thirty-two strains carried plasmids and 21 profile types were identified; 17 strains were resistant to antimicrobial agents. In contrast only six of the type strains carried IS 200 elements and three patterns were identified. Within Salm. virchow phage type 31, five of 10 wild-type isolates carried plasmids and two plasmid profiles were identified; in contrast, an IS 200 element was identified in the genome of only one of these strains. It is concluded that for Salm. virchow , IS 200 is unlikely to significantly extend the degree of discrimination achieved by phage typing which may be supplemented when appropriate by plasmid profile typing.     

Differentiation of Shigella strains by plasmid profile analysis, serotyping and phage typing

Ninety-one Shigella flexneri and 29 Shigella sonnei strains isolated during 1994 from sporadic cases of shigellosis and healthy carriers were analyzed for plasmid profile in order to compare the discriminating ability of this method with that of serotyping and phage typing. Our study revealed 10 plasmid profiles (PP) among S. sonnei strains. A total of 26 out of 29 (89%) S. sonnei isolates could be placed into two phage types (type 1 and 20) comprising four PP for phage type 1 and seven PP for type 20, respectively. Twenty-three different PP were identified among S. flexneri strains. Each serotype was associated with a specific predominant plasmid profile, except serotype 2a. This serotype, the most frequently isolated in Romania, was still rather homogeneous: 33 out of 39 isolates belonged to phage type 125, 27 of which could be placed into two related PP (F10 and F17). Comparison of plasmid patterns of epidemiologically independent S. flexneri serotype 2a isolates with those exhibited by 45 serotype 2a isolates associated to six independent outbreaks revealed the same homogeneity. Thirty-eight strains, representing 4 of 6 outbreaks, had F10 and F17 plasmid patterns. The discrimination indices (D) for plasmid profile analysis alone (D = 0.890) and for the combination of serotyping and phage typing (D = 0.841) indicate that both typing systems have a nearly similar ability of discriminating among S. flexneri strains. By combining the results of the three typing methods, a total of 42 types are distinguished and the D value is 0.942. Our data suggest that plasmid profile analysis can complement phenotyping methods resulting in a degree of discrimination that cannot be achieved by either system alone.     

Comparison of Pulsed-Field Gel Electrophoresis, Ribotyping, and Plasmid Profiling for Typing of Vibrio anguillarum Serovar O1

A total of 75 Vibrio anguillarum serogroup O1 strains were studied with respect to their plasmid contents, ribotypes, and pulsed-field gel electrophoresis (PFGE) patterns. Eight plasmid profiles and six ribotypes were demonstrated, and one profile was dominant by both typing methods. In contrast, PFGE had very high discriminatory power, demonstrating 35 profiles. On the basis of PFGE patterns, a similarity matrix and a dendrogram were constructed. The results indicated that Scandinavian strains and southern European isolates (with some exceptions) belong to two different clonal lineages. A few strains from the United States and United Kingdom deviated considerably from each other and from Scandinavian and southern European strains.     

BamHI restriction endonuclease analysis of Yersinia ruckeri plasmids and their relatedness to the genus Yersinia 42- to 47-megadalton plasmid

The plasmid profile and BamHI restriction pattern of 17 sorbitol-negative and 1 sorbitol-positive French Yersinia ruckeri strain of the American type strain were studied. The 17 sorbitol-negative strains and the American strain harbored a 62-megadalton (MDa) plasmid with an identical BamHI restriction pattern. Southern hybridization indicated that this 62-MDa plasmid is common among these various strains. The sorbitol-positive strain had four plasmid bands (70, 62, 32, and 25 MDa), and there was no comigration of the DNA fragments of these cleaved plasmids with the fragments of the 62-MDa plasmid. Hybridization of these restricted plasmids with the common 62-MDa plasmid showed a weak DNA homology. The Y. ruckeri plasmid (62 MDa) had a different molecular weight than the virulence plasmid (42 to 47 MDa) of the genus Yersinia, and they had different BamHI restriction patterns. Furthermore, no sequence of the Y. ruckeri plasmid DNA was recognized after Southern hybridization when the 47-MDa plasmid of Y. enterocolitica was used as a probe.     

BamHI restriction endonuclease analysis of Yersinia ruckeri plasmids and their relatedness to the genus Yersinia 42- to 47-megadalton plasmid.

The plasmid profile and BamHI restriction pattern of 17 sorbitol-negative and 1 sorbitol-positive French Yersinia ruckeri strain of the American type strain were studied. The 17 sorbitol-negative strains and the American strain harbored a 62-megadalton (MDa) plasmid with an identical BamHI restriction pattern. Southern hybridization indicated that this 62-MDa plasmid is common among these various strains. The sorbitol-positive strain had four plasmid bands (70, 62, 32, and 25 MDa), and there was no comigration of the DNA fragments of these cleaved plasmids with the fragments of the 62-MDa plasmid. Hybridization of these restricted plasmids with the common 62-MDa plasmid showed a weak DNA homology. The Y. ruckeri plasmid (62 MDa) had a different molecular weight than the virulence plasmid (42 to 47 MDa) of the genus Yersinia, and they had different BamHI restriction patterns. Furthermore, no sequence of the Y. ruckeri plasmid DNA was recognized after Southern hybridization when the 47-MDa plasmid of Y. enterocolitica was used as a probe.     

Occurrence of chromium resistant thermotolerant coliforms in tannery effluent

Twenty six thermotolerant strains resistant to high levels of chromium (50-250 microg/ml) were isolated from treated tannery effluent. They were also found resistant to multiple heavy metals and antibiotics. Majority of them were resistant to copper and bacitracin. Nine strains representing different resistance patterns were selected for plasmid profile and conjugation studies. Agarose gel electrophoresis results revealed that 6 strains harboured a single plasmid, whereas 3 strains exhibited 2 plasmid bands. Among antimicrobials, co-trimazole and bacitracin and among metals, Cu2+, Cd2+, Zn2+ and Ni2+ resistance were transferred most frequently at variable rates. However, chromium resistance was transferred in 6 strains with a frequency ranging 19-49x10(-2). Resistance to Co2+ and Hg2+ did not transfer under environmental conditions. Among the nine strains, three were found predominantly uropathogenic Escherichia coli (UPEC) serotype 04, whereas two strains were untypable. In addition, 4 transconjugants also showed a positive result after serotyping.     

Characterization of Bacillus thuringiensis soil isolates from Cuba, with insecticidal activity against mosquitoes

Chemical insecticides may be toxic and cause environmental degradation. Consequently, biological control for insects represents an alternative with low ecological impact. In this work, three soil isolates (A21, A51 and C17) from different regions of the Cuban archipelago were identified, characterized and evaluated against Aedes aegypti and Culex quinquefasciatus. The new isolates were compared with reference IPS82 strain and two strains isolated from biolarvicides Bactivec and Bactoculicida, respectively. The differentiation was done by morphological, biochemical, bioassays activity and molecular methods (SDS-PAGE, plasmid profile and random amplified polymorphic analysis). All isolates were identified as Bacillus thuringiensis. The A21, A51 and C17 isolates showed higher larvicide activity than Bactivec's isolated reference strain, against both A. aegypti and C. quinquefasciatus. A21 isolate had a protein profile similar to IPS82 and Bactivec strain. A51 and C17 isolates produced a characteristic proteins pattern. A21 and A51 isolates had plasmid patterns similar to IPS82 standard strain, while C17 isolate had different both plasmid profile and protein bands. All the studied isolates showed a diverse RAPD patterns and were different from the strains previously used in biological control in Cuba.     

Intraspecific characterization of Vibrio tapetis strains by use of pulsed-field gel electrophoresis, ribotyping, and plasmid profiling.

A total of twenty-two strains of Vibrio tapetis, the causative agent of brown ring disease affecting cultured clams, were compared and evaluated in an investigation of strain heterogeneity using pulsed-field gel electrophoresis (PFGE), ribotyping, and plasmid profile analysis. A total of 90.9% of V. tapetis strains tested by using NotI showed the same PFGE pattern, consisting of 15 bands. In contrast, the V. tapetis strains showed a low degree of similarity with six reference Vibrio species tested. All V. tapetis strains harbored a large plasmid of 74.5 kb. This plasmid was not detected in any of the other Vibrio species. In addition, endonuclease restriction analysis of the plasmid content of the strains using EcoRI and HindIII clearly showed that all the strains of V. tapetis possessed the same cleavage pattern. The three enzymes used for ribotyping, PvuII, SmaI, and SalI, yielded patterns with 8 to 12 bands ranging in size from 2 to 23 kb. The application of the SalI and SmaI endonuclease rendered the separation of the strains tested in two ribotypes, while all the V. tapetis strains belonged to the same ribotype when the enzyme PvuII was used.     

Genetic Diversity of a Natural Population of Sinorhizobium melilotiRevealed in Analysis of Cryptic Plasmids and ISRm2011-2 Fingerprints

Fifty-six natural strains of alfalfa nodule bacteria were isolated from samples of the soil under wild legume and alfalfa in two different field sites of Irkutsk oblast. Based on the results of analysis of plasmid profile, 11 different types of strains were detected, and 43 types were identified based on the results of hybridization with the insertion sequence element ISRm2011-2. Significant differences were found in the plasmid profile and IS fingerprints between strains isolated from the soil under alfalfa and the soil under legume. In contrast, strains growing at some distance from each other differed only in the IS fingerprints. From a comparison of results obtained in the assessment of plasmid profile and in analysis of IS fingerprints with results of RFLP analysis in strains, the conclusion about the transference of cryptic plasmids between strains and genetic rearrangements in strains of this population was drawn.     

Biotype and macromolecular profiles of cytotoxin-producing strains of Helicobacter pylori from antral gastric mucosa

Biotype, genome, protein and plasmid profile diversity amongst 40 epidemiologically unrelated strains of Helicobacter pylori was studied. Strains were API Zym biotypes II, III and IV but most (87%) were biotype II. Four subsets of strains were defined on a combination of motility (56% positive) and cytotoxin production (44% positive). A close association (P = 0.45) between these two features was observed for 69% of strains. Each strain of H. pylori had a unique DNA type defined by either HaeIII or HindIII total digest patterns and by ribopatterns, except for DNA of the rare strains not cut by these endonucleases. Strain diversity was confirmed by one-dimensional SDS-PAGE electrophoretic protein patterns. No consistent associations between cytotoxin activity and overall ribopattern or band subsets within a ribopattern were detected. Some strains (39%) contained a plasmid but the presence of plasmids was not consistently associated with either cytotoxin activity, biotype, motility or ribopattern. We conclude that the cytotoxin-producing strains of H. pylori were genomically as diverse as the non-cytotoxin producing strains.