DNA intercalating drugs inhibit positive supercoiling induced by novobiocin in halophilic archaea

Abstract The major outer membrane protein of Neisseria gonorrhoeae , Por, functions as a porin and is thought to occur as one gene with two alleles. The immunologically distinct epitopes of the two subclasses, IA and IB, have allowed the development of serotyping schemes. Clinical isolates of N. gonorrhoeae are believed to express only a single type of Por, either IA or IB. We have encountered two clusters of isolates that react with antibodies to both IA and IB Por. Isolates within the clusters are indistinguishable by the phenotypic characteristics tested. In addition, the amplification of the por gene in representative isolates showed that the por gene of the hybrids gave similar restriction digest patterns within but not between the clusters.     

Lethal activity of miconazole in Neisseria gonorrhoeae grown in pure and mixed cultures

Abstract Low concentrations (e.g. 2 × 10⁻⁶ M) of an imidazole derivative anti-fungal agent, miconazole, were lethal for the Gram-negative, facultative aerobic pathogen Neisseria gonorrhoeae grown either alone or in mixed culture with the yeast Candida albicans . Electron microscopic observation of Neisseria cells exposed to miconazole showed the presence of blebs in the outer wall and areas of separation between the wall and the cytoplasmic membrane. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of cell lysates did not reveal differences in major outer membrane proteins between the treated and the untreated cells of any one strain. Imidazole derivatives are frequently used in the treatment of candidiasis. Our in vitro results show that low concentrations of one of them, miconazole, can be bactericidal for N. gonorrhoeae , a bacterium that can colonise sites of the human body where Candida is often found.     

Sequence analysis and relationships between meningococcal class 3 serotype proteins and other porins from pathogenic and non-pathogenic Neisseria species

The presence of highly conserved regions within previously determined porin gene sequences from Neisseria meningitidis and Neisseria gonorrhoeae permitted the construction of oligonucleotide primers for PCR amplification of other neisserial porin genes. Although two separate porin genes (porA and porB) are present in N. meningitidis only a single fragment, corresponding to porB, could be amplified from this species. The amplified porB genes from four different meningococcal serotypes, which express the class 3 outer membrane protein, were sequenced. Amplified fragments corresponding to porin genes from N. lactamica and N. sicca were also sequenced. In common with the known neisserial porins, models of the organisation of the predicted proteins indicated trans-membrane structures with eight surface exposed loops. In the meningococcal class 3 proteins the main regions of sequence variation, which must be responsible for serotype specificity, were located on loops 5 and 7. A phylogenetic analysis of the family of porins from the Neisseria confirmed the close relationship of the meningococcal class 3 protein with the gonococcal PIA protein, while the gonococcal PIB protein was shown to be closely related to the N. lactamica porin. The close relationship seen between porins of the pathogenic and non-pathogenic Neisseriae identified no obvious virulence-associated regions in the proteins, but did suggest that the current nomenclature for neisserial porin genes may need reviewing.     

淋球菌耐药性与耐药质粒的研究

为了解湛江地区淋球菌耐药现状及耐药质粒的分布,并初步探讨其相互关系,对１９９８￣１９９９年广东省湛江地区健康鉴定出的９８株淋球菌流行株,应用纸片扩散法测定细胞对１０种抗生素的敏感性,并采用碱裂解法进行质粒抽提,分析耐药质粒的分布情况,选取ＮＧ４、ＮＧ３１、ＮＧ４３、ＮＧ７０进行细菌的接合试验,以观察耐药质粒能否通过接合进行传递以及传递后受体菌耐药性的变化。结果显示６．１２％菌株对全部抗生素敏感,４８．９６％的菌株对３种及３种以上的抗生素耐药;共检出四种不同分子量的质闰,７．４ｋｂ和４．２ｋｂ质粒检出率较高,分别为５９．１６％和６７．３２％,质粒谱型１２种,以７．４ｋｇ＋４．２ｋｇ和３９．５ｋｇ＋７．４ｋｇ＋４．２ｋｇ为主,占３８．７６％。在细菌的接合传递试验中,ＮＧ４３可通过接合传递将其耐药性传递给淋球菌及大肠     

耐药淋球菌相关核苷酸序列的克隆与初步分析*

为克隆淋球菌染色体耐药相关核苷酸序列,我们利用抑制性消减杂交技术构建耐药性淋球菌与标准参考菌株差异DNA消减库,从中筛选淋球菌耐药相关核苷酸序列。通过初步筛选,对克隆得到的DNA片段进行测序,经GenBank和淋球菌基因组序列库检索分析,发现5个未知新核苷酸序列。这些核苷酸序列可能与淋球菌染色体耐药性相关,将为研究淋球菌耐药性提供新的实验对象。     

Competition between Neisseria gonorrhoeae and Staphylococcus epidermidis during iron-limited or replete continuous culture

Neisseria gonorrhoeae strain P9-2 was grown in iron-limited or replete continuous culture at a dilution rate of 0.05 h-1, in the presence and absence of Staphylococcus epidermidis. Gonococci maintained expression of pili (P+) and the transparent colony phenotype in pure culture during transitions of iron- and cystine-limited growth. They competed well with staphylococci during iron-limited co-culture and comprised greater than 95% of the population. Transition to cystine-limited growth allowed the staphylococcus to predominate but the gonococcus did not wash out. Furthermore, the gonococcal opaque colony phenotype (O+), indicating synthesis of outer membrane proteins II, was now expressed. Restoration of iron limitation returned the co-culture to its original composition but with P+O+ gonococci dominating. These results suggest that environments might exist in Man where gonococci can compete successfully with normal indigenous bacteria during infection.     

杭州市淋病奈瑟菌质粒酶切图谱分析研究

目的 :了解杭州市淋病奈瑟菌质粒携带及质粒谱型分布情况。方法 :采用碱裂解法对门诊 2 0 0 0年 1月～ 2 0 0 1年 10月分离的 2 0 7株淋病奈瑟菌进行了质粒抽提及质粒谱分型研究 ,并对菌株的青霉素耐药现象和耐药性质粒的关系进行探讨。结果 :2 0 7株淋病奈瑟菌中 194株 (93 .7% )检见质粒带 ,其中含一条质粒带的 112株 (5 4.11% ) ,含两条质粒带的 12株 (5 .8% ) ,含三条带的 70株 (3 3 .82 % ) ,尚有 13株(6.2 8% )未检测到质粒。以 E.coli V5 17细菌质粒作分子量标准 ,测得这些分子量分别为 2 .6、4.5、和 2 4.5Md。质粒谱型以 2 .6 4.5 2 4.5 Md(3 3 .82 % )多见。结论 :杭州地区质粒酶切图谱的分析研究有助于淋病的治疗和防治 ,这将对该地区淋病奈瑟菌的分子流行病学调查和淋病监控提供依据     

1998～2002年广州地区淋球菌对抗生素耐药性的变迁

目的 :了解 1998～ 2 0 0 2年广州地区淋球菌对 5种抗生素的耐药性的变迁及产青霉素酶淋球菌(PPNG)和高水平耐四环素淋球菌 (TRNG)的流行状况。方法 :用琼脂稀释法测定最低抑菌浓度 (MIC)以及用纸片碘量法检测β-内酰胺酶。结果 :60 3株淋球菌检出 PPNG 64株 (10 .6% )、TRNG 83株 (13 .7% ) ,1998～ 2 0 0 2年 ,PPNG、TRNG流行率及环丙沙星耐药率 ,经μ检验 ,P<0 .0 1,差异有显著性。头孢曲松、壮观霉素未发现耐药菌株 ,壮观霉素抗菌活性最强。结论 :持续监测淋球菌的耐药性十分重要     

淋病奈瑟球菌的耐药性检测

目的了解淋病奈瑟球菌对临床常见药物的耐药性。方法采用琼脂稀释法测定13种抗菌药物对35株淋病奈瑟球菌的MICs;Nitrocefin(头孢硝噻酚)纸片检测β-内酰胺酶,并采用PCR测定其基因型。结果淋病奈瑟球菌对青霉素、四环素、环丙沙星与头孢呋辛的耐药率分别为65．7％、60．0％、88．6％与14．3％,对第3、4代头孢菌素、大观霉素非常敏感,耐药率均为0％;42．9％的菌株产生TEM型β-内酰胺酶。结论淋病奈瑟球菌对青霉素、四环素类和氟喹诺酮类的耐药性高,治疗宜选用第3、4代头孢菌素和大观霉素等,同时加强耐药性监测。     

Determination of the number of tuf genes in Chlamydia trachomatis and Neisseria gonorrhoeae

Restriction endonuclease fragments of DNA from Neisseria gonorrhoeae and Chlamydia trachomatis (mouse pneumonitis biovar) were hybridized to probes from the N-terminal and C-terminal portions of the Escherichia coli tufA gene. In common with other Gram-negative bacteria, the genome of N. gonorrhoeae was found to contain two homologous sequences (presumptive tuf genes). The C. trachomatis genome contained a single tuf sequence.     

淋病奈瑟菌感染实验室检测技术的进展

细菌培养是诊断淋病奈瑟菌(NG)感染的\"金标准\",也是目前诊断淋病最可靠的方法.但淋病奈瑟菌在人体外抵抗力极弱,不易培养;仅做细菌形态学检查,诊断意义有限.随着淋病奈瑟菌耐药性不断增强,多重耐药菌出现并广泛传播.高敏感性、高特异性、操作简便的分子生物学检验技术,如单管多重聚合酶链反应(PCR)技术等,已开始用于淋病奈瑟...     

A fully defined, clear and protein-free liquid medium permitting dense growth of Neisseria gonorrhoeae from very low inocula

Neisseria gonorrhoeae is difficult to cultivate in liquid medium. Currently there are no liquid media, defined or undefined, that reliably permit growth of this bacterium from low inocula. Standard clinical laboratory broths may allow multiplication of some strains of gonococci from large inocula, but such media incorporate infusates, extracts or digests and are therefore undefined. In this study, 20 gonococci of ten auxotypes were tested in various experimental media in the development of an easily prepared chemically defined, clear and protein-free liquid medium. The final medium - GW medium - allowed the growth of three clinical isolates of gonococci from inocula of <10(3) CFU mL(-1) to >10(8) CFU mL(-1) by 24 h. None of four commercially-available broths (nutrient broth, brain heart infusion, tryptone soya broth, and Mueller-Hinton broth) tested in parallel reliably supported growth of these isolates to the same extent. GW medium should be useful for studies of the growth of gonococci under different conditions and, as the medium is clear and colorless, this can be monitored turbidometrically. GW medium may be suitable as a basal medium for biochemical identification tests, antimicrobial susceptibility determinations and antimicrobial synergy studies.     

Neisseria gonorrhoeae possesses two nicotinamide adenine dinucleotide-independent lactate dehydrogenases

Abstract An important metabolic capability of Neisseria gonorrhoeae is the utilization of host-derived lactate. Two isoenzymes of the membrane-associated, pyridine dinucleotide-independent type of lactate dehydrogenase (iLDH) participate in lactate assimilation, but exhibit distinctive properties. Isoenzyme iLDH-I utilized lactate exclusively as substrate, exhibiting a preference for the D-isomer. In contrast, isoenzyme iLDH-II exhibited broad substrate specificity (lactate, phenyllactate, and 4-hydroxyphenyllactate), but was stereospecific for the L-isomers. These results explain the difficulty in isolating mutants unable to utilize lactate.     

淋病奈瑟菌对hCD46基因转染COS-1细胞的黏附

为研究hCD46在菌毛介导的淋病奈瑟菌宿主特异性黏附过程中的作用。用连接PCR技术扩增出启动子与cDNA相连的hCD46小基因,并将其置换出pcDNA3.1载体中的CMV启动子,构建成重组真核表达载体pCD46。转染COS-1细胞后用间接免疫荧光法检测到hCD46 cDNA在其自身启动子的指导下可在COS-1细胞膜表面有效表达,Western blotting检测表明表达产物的分子正确,用流式细胞术分选表达hCD46的基因转染细胞COS-1-46。细菌黏附实验显示菌毛阳性淋病奈瑟菌临床分离株对COS-1-46细胞有较强的黏附性。提示hCD46是菌毛介导的淋病奈瑟菌特异性黏附于人黏膜细胞的一种重要受体,hCD46小基因可用于淋病奈瑟菌感染转基因小鼠模型的制备。     

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。