Identification of the conjugative mef gene in clinical Acinetobacter junii and Neisseria gonorrhoeae isolates

The mef gene, originally described for gram-positive organisms and coding for an efflux pump, has been identified in clinical isolates of Acinetobacter junii and Neisseria gonorrhoeae. These strains could transfer the mef gene at frequencies ranging from 10(-6) to 10(-9) into one or more of the following recipients: gram-negative Moraxella catarrhalis, Neisseria perflava/sicca and Neisseria mucosa and gram-positive Enterococcus faecalis. Three Streptococcus pneumoniae strains could transfer the mef gene into Eikenella corrodens, Haemophilus influenzae, Kingella denitrificans, M. catarrhalis, Neisseria meningitidis, N. perflava/sicca, and N. mucosa at similar frequencies. The mef gene can thus be transferred to and expressed in a variety of gram-negative recipients.     

Host range of the conjugative 25.2-megadalton tetracycline resistance plasmid from Neisseria gonorrhoeae and related species.

High-level tetracycline resistance in strains of Neisseria gonorrhoeae, Neisseria meningitidis, Kingella denitrificans, and Eikenella corrodens has recently been described. The resistance in each species is due to the acquisition of 25.2-megadalton conjugative plasmids that carry the tetracycline resistance determinant TetM. We examined the ability of commensal Neisseria species to serve as recipients in conjugation for these new plasmids. Most of the recipients (n = 21) tested had detectable conjugation frequencies (greater than 10(-9] with one or more of the donor strains. Transfer was not detected in Branhamella catarrhalis. Transconjugants were able to maintain the plasmids and act as donors in subsequent matings.     

Neisseria lactamica and Neisseria polysaccharea as possible sources of meningococcal beta-lactam resistance by genetic transformation.

We studied the susceptibilities of relatively penicillin G-resistant and -susceptible strains of Neisseria meningitidis, as well as Neisseria lactamica and Neisseria polysaccharea, to penicillin, ampicillin, and several cephalosporins. The MICs of penicillin, ampicillin, cephalothin, and cefuroxime for moderately resistant meningococci have increased two- to sixfold in relation to MICs for susceptible strains. For these strains of meningococci, N. lactamica, and N. polysaccharea, penicillin, ampicillin, cephalothin, and cefuroxime MICs for 50 and 90% of strains were similar. By genetic transformation of a penicillin-susceptible strain of N. meningitidis to low-level penicillin resistance with DNA from penicillin-resistant strains of N. meningitidis, N. lactamica, N. polysaccharea, and N. gonorrhoeae, isogenic strains with the same pattern of resistance to beta-lactams were obtained, suggesting that these commensal Neisseria spp. could be the source of meningococcal resistance genes.     

Susceptibility of Neisseria gonorrhoeae to antimicrobial peptides from amphibian skin, dermaseptin, and derivatives

We evaluated the antimicrobial effect of antimicrobial peptides from frog skin belonging to the dermaseptin family against reference and clinical Neisseria gonorrhoeae strains, including penicillin-resistant strains. Dermaseptin S4 exhibited anti-N. gonorrhoeae activity against all strains with MICs ranging between 10 and 100 microg/mL. We then used derivatives of DS4 and determined the anti-N. gonorrhoeae activity of each of analogs. All the derivatives showed antimicrobial activity. Among the different molecules tested, we found that dermaseptins K4S4 (1-16)a and K4S4 (1-28) were the more potent to inhibit N. gonorrhoeae growth with MIC of 10 microg/mL against all strains.     

Dihydrofolate Reductase from Neisseria sp

Members of the genus Neisseria are relatively nonsusceptible to trimethoprim, an inhibitor of dihydrofolate reductase. For example, the minimal inhibitory concentration (MIC) of trimethoprim for N. gonorrhoeae ranges from 2 to 70 mug/ml, whereas the MIC for Escherichia coli is 0.2 mug/ml or less. In an effort to understand this difference, dihydrofolate reductase was partially purified from five Neisseria species and compared with the enzyme from E. coli. N. gonorrhoeae dihydrofolate reductase was similar to that from E. coli in molecular weight (18,000) and affinity for the substrates reduced nicotinamide adenine dinucleotide phosphate and dihydrofolate (K(m) = 13 and 8 muM, respectively). However, the gonococcal enzyme had a decreased affinity for trimethoprim, with an apparent K(i) of 45 x 10(-9) M, some 30-fold greater than the E. coli value of 1.2 x 10(-9) M. These enzymes also differed in their isoelectric points and pH activity profiles. Within the genus Neisseria, the dihydrofolate reductase isolated from N. meningitidis and N. lactamica resembled the N. gonorrhoeae enzyme, and only small differences were detected for the N. flavescens and Branhamella catarrhalis dihydrofolate reductases. These data indicate that the relatively poor affinity of trimethoprim for the dihydrofolate reductase from these organisms may be largely responsible for the relative nonsusceptibility of Neisseria sp. to trimethoprim. The contribution of other resistance mechanisms to the overall nonsusceptibility was assessed. Strains of N. gonorrhoeae with altered cell envelope permeability had MIC values less than twofold different from those of isogenic wild-type strains. Also, a direct relationship was observed between the affinity of trimethoprim analogs for gonococcal dihydrofolate reductase and the MIC of these compounds for the gonococcus. These observations suggest that the cell envelope of N. gonorrhoeae is not impermeable to trimethoprim. Changes in the amount of dihydrofolate reductase activity could cause alterations in the susceptibility of the gonococcus to trimethoprim, as demonstrated with N. gonorrhoeae strains selected for trimethoprim resistance after chemical mutagenesis. However, the level of dihydrofolate reductase activity in wild-type N. gonorrhoeae was similar to that of E. coli, indicating that the difference in the susceptibility of these organisms is not due to greater amounts of enzyme in N. gonorrhoeae.     

不可分群脑膜炎奈瑟菌PCR基因分型研究

目的对自健康人群鼻咽拭子中分离的74株表型特征为不可分群的脑膜炎奈瑟菌,利用PCR基因分型技术进行基因特征分析。方法用PCR方法扩增脑膜炎奈瑟菌种属特异性基因crgA和A、B、C、W135、Y、Z、X以及29E不同群的特异性基因片段,确定不同菌株的基因型。结果以脑膜炎奈瑟菌crgA基因为靶基因进行PCR扩增,74株不可分群脑膜炎奈瑟菌中,66株脑膜炎奈瑟菌crgA基因扩增阳性,检出率89.19%。66株菌株进行不同血清群的PCR分群鉴定,40株菌株（60.61%）可检测为不同的血清群基因型,B群27株,29E群7株,X、Y群各2株,C、W135各1株。结论不可分群脑膜炎奈瑟菌进行PCR基因分型研究对脑膜炎奈瑟菌的研究具有重要的流行病学意义。     

A DNA sequence for the discrimination of Neisseria gonorrhoeae from other Neisseria species.

A 350 base pair Neisseria gonorrhoeae DNA restriction fragment was cloned after subtractive hybridization to Neisseria meningitidis DNA. This restriction fragment hybridized to 105 out of 106 N. gonorrhoeae strains tested. While three N. meningitidis strains did not hybridize to this probe, Neisseria mucosa DNA exhibited cross-hybridization. This particular clone was used to screen a N. gonorrhoeae genomic DNA library. A positive 2.4 kilobase pair clone was shown by DNA sequencing to contain two long open reading frames. One open reading frame did not hybridize to N. mucosa and other Neisseria species, while it retained specificity for the original 105 N gonorrhoeae strains. This open reading frame also showed significant homology to cytosine DNA methyltransferases.     

杭州市余杭区淋病奈瑟菌血清学分型研究

目的：确定杭州市余杭区淋病奈瑟菌血清型流行特点。方法：采用单克隆抗体分型技术对门诊2000年1月－2001年10月分离的207株淋病奈瑟菌进行了抗原性测定。结果：207株淋病奈瑟菌血清学分型检测显示94株（45．4％）属于WⅠ群；87株（42．0％）属WⅡ/Ⅲ；26株（12．6％）淋病奈瑟菌与WⅠ和WⅡ／Ⅲ两种试剂均产生凝集反应。结论：引起杭州市淋病流行的菌株在血清学上尚未形成优势群，也表明了现阶段本地区淋巴病患传染源的多源性。     

淋球菌流行株对5种抗生素敏感性分析

目的 检测2008年度临床分离的淋球菌对青霉素、四环素、大观霉素、头孢曲松和环丙沙星的敏感性,分析耐药菌株的流行特点.方法 采用琼脂稀释法测定菌株对5种抗生素的最小抑菌浓度(MIC),判断其敏感性并按WHO西太平洋地区淋球菌耐药性监测统一标准.用纸片酸度法检测产β-内酰胺酶淋球菌菌株.结果 107株淋球菌中,检出94株对青霉素耐药(87.9%),产β-内酰胺酶淋球菌43株(40.2%);四环素耐药率为88.8%,其中质粒介导高度耐四环素淋球菌(TRNG)63株(58.9%);环丙沙星耐药率81.3%;未发现对大观霉素和头孢曲松耐药菌株.青霉索、四环素和环丙沙星的MIC50及MIC90均已超过耐药标准,尤以青霉素为甚,其MIC50及MIC90均超过耐药标准1、32倍.结论 淋球菌对大观霉素和头孢曲松的敏感性较高,可作为治疗的首选药物;对青霉素、四环素和环丙沙星耐药率较高,提示对淋病的治疗作用差.     

淋球菌流行株对5种抗生素敏感性分析

目的 检测2008年度临床分离的淋球菌对青霉素、四环素、大观霉素、头孢曲松和环丙沙星的敏感性,分析耐药菌株的流行特点.方法 采用琼脂稀释法测定菌株对5种抗生素的最小抑菌浓度(MIC),判断其敏感性并按WHO西太平洋地区淋球菌耐药性监测统一标准.用纸片酸度法检测产β-内酰胺酶淋球菌菌株.结果 107株淋球菌中,检出94株对青霉素耐药(87.9%),产β-内酰胺酶淋球菌43株(40.2%);四环素耐药率为88.8%,其中质粒介导高度耐四环素淋球菌(TRNG)63株(58.9%);环丙沙星耐药率81.3%;未发现对大观霉素和头孢曲松耐药菌株.青霉索、四环素和环丙沙星的MIC50及MIC90均已超过耐药标准,尤以青霉素为甚,其MIC50及MIC90均超过耐药标准1、32倍.结论 淋球菌对大观霉素和头孢曲松的敏感性较高,可作为治疗的首选药物;对青霉素、四环素和环丙沙星耐药率较高,提示对淋病的治疗作用差.     

淋球菌流行株对5种抗生素敏感性分析

目的 检测2008年度临床分离的淋球菌对青霉素、四环素、大观霉素、头孢曲松和环丙沙星的敏感性,分析耐药菌株的流行特点.方法 采用琼脂稀释法测定菌株对5种抗生素的最小抑菌浓度(MIC),判断其敏感性并按WHO西太平洋地区淋球菌耐药性监测统一标准.用纸片酸度法检测产β-内酰胺酶淋球菌菌株.结果 107株淋球菌中,检出94株对青霉素耐药(87.9%),产β-内酰胺酶淋球菌43株(40.2%);四环素耐药率为88.8%,其中质粒介导高度耐四环素淋球菌(TRNG)63株(58.9%);环丙沙星耐药率81.3%;未发现对大观霉素和头孢曲松耐药菌株.青霉索、四环素和环丙沙星的MIC50及MIC90均已超过耐药标准,尤以青霉素为甚,其MIC50及MIC90均超过耐药标准1、32倍.结论 淋球菌对大观霉素和头孢曲松的敏感性较高,可作为治疗的首选药物;对青霉素、四环素和环丙沙星耐药率较高,提示对淋病的治疗作用差.     

淋球菌流行株对5种抗生素敏感性分析

目的 检测2008年度临床分离的淋球菌对青霉素、四环素、大观霉素、头孢曲松和环丙沙星的敏感性,分析耐药菌株的流行特点.方法 采用琼脂稀释法测定菌株对5种抗生素的最小抑菌浓度(MIC),判断其敏感性并按WHO西太平洋地区淋球菌耐药性监测统一标准.用纸片酸度法检测产β-内酰胺酶淋球菌菌株.结果 107株淋球菌中,检出94株对青霉素耐药(87.9%),产β-内酰胺酶淋球菌43株(40.2%);四环素耐药率为88.8%,其中质粒介导高度耐四环素淋球菌(TRNG)63株(58.9%);环丙沙星耐药率81.3%;未发现对大观霉素和头孢曲松耐药菌株.青霉索、四环素和环丙沙星的MIC50及MIC90均已超过耐药标准,尤以青霉素为甚,其MIC50及MIC90均超过耐药标准1、32倍.结论 淋球菌对大观霉素和头孢曲松的敏感性较高,可作为治疗的首选药物;对青霉素、四环素和环丙沙星耐药率较高,提示对淋病的治疗作用差.     

淋球菌流行株对5种抗生素敏感性分析

目的 检测2008年度临床分离的淋球菌对青霉素、四环素、大观霉素、头孢曲松和环丙沙星的敏感性,分析耐药菌株的流行特点.方法 采用琼脂稀释法测定菌株对5种抗生素的最小抑菌浓度(MIC),判断其敏感性并按WHO西太平洋地区淋球菌耐药性监测统一标准.用纸片酸度法检测产β-内酰胺酶淋球菌菌株.结果 107株淋球菌中,检出94株对青霉素耐药(87.9%),产β-内酰胺酶淋球菌43株(40.2%);四环素耐药率为88.8%,其中质粒介导高度耐四环素淋球菌(TRNG)63株(58.9%);环丙沙星耐药率81.3%;未发现对大观霉素和头孢曲松耐药菌株.青霉索、四环素和环丙沙星的MIC50及MIC90均已超过耐药标准,尤以青霉素为甚,其MIC50及MIC90均超过耐药标准1、32倍.结论 淋球菌对大观霉素和头孢曲松的敏感性较高,可作为治疗的首选药物;对青霉素、四环素和环丙沙星耐药率较高,提示对淋病的治疗作用差.     

淋球菌流行株对5种抗生素敏感性分析

目的 检测2008年度临床分离的淋球菌对青霉素、四环素、大观霉素、头孢曲松和环丙沙星的敏感性,分析耐药菌株的流行特点.方法 采用琼脂稀释法测定菌株对5种抗生素的最小抑菌浓度(MIC),判断其敏感性并按WHO西太平洋地区淋球菌耐药性监测统一标准.用纸片酸度法检测产β-内酰胺酶淋球菌菌株.结果 107株淋球菌中,检出94株对青霉素耐药(87.9%),产β-内酰胺酶淋球菌43株(40.2%);四环素耐药率为88.8%,其中质粒介导高度耐四环素淋球菌(TRNG)63株(58.9%);环丙沙星耐药率81.3%;未发现对大观霉素和头孢曲松耐药菌株.青霉索、四环素和环丙沙星的MIC50及MIC90均已超过耐药标准,尤以青霉素为甚,其MIC50及MIC90均超过耐药标准1、32倍.结论 淋球菌对大观霉素和头孢曲松的敏感性较高,可作为治疗的首选药物;对青霉素、四环素和环丙沙星耐药率较高,提示对淋病的治疗作用差.     

淋球菌流行株对5种抗生素敏感性分析

目的检测2008年度临床分离的淋球菌对青霉素、四环素、大观霉素、头孢曲松和环丙沙星的敏感性,分析耐药菌株的流行特点。方法采用琼脂稀释法测定菌株对5种抗生素的最小抑菌浓度（MIC）,判断其敏感性并按WHO西太平洋地区淋球菌耐药性监测统一标准。用纸片酸度法检测产β-内酰胺酶淋球菌菌株。结果107株淋球菌中,检出94株对青霉素耐药（87．9％）,产β-内酰胺酶淋球菌43株（40．2％）;四环素耐药率为88．8％,其中质粒介导高度耐四环素淋球菌（TRNG）63株（58．9％）;环丙沙星耐药率81．3％;未发现对大观霉素和头孢曲松耐药菌株。青霉素、四环素和环丙沙星的MIC50及MIC90均已超过耐药标准,尤以青霉素为甚,其MIC50及MIC90均超过耐药标准1、32倍。结论淋球菌对大观霉素和头孢曲松的敏感性较高,可作为治疗的首选药物;对青霉素、四环素和环丙沙星耐药率较高,提示对淋病的治疗作用差。     

淋球菌流行株对5种抗生素敏感性分析

目的 检测2008年度临床分离的淋球菌对青霉素、四环素、大观霉素、头孢曲松和环丙沙星的敏感性,分析耐药菌株的流行特点.方法 采用琼脂稀释法测定菌株对5种抗生素的最小抑菌浓度(MIC),判断其敏感性并按WHO西太平洋地区淋球菌耐药性监测统一标准.用纸片酸度法检测产β-内酰胺酶淋球菌菌株.结果 107株淋球菌中,检出94株对青霉素耐药(87.9%),产β-内酰胺酶淋球菌43株(40.2%);四环素耐药率为88.8%,其中质粒介导高度耐四环素淋球菌(TRNG)63株(58.9%);环丙沙星耐药率81.3%;未发现对大观霉素和头孢曲松耐药菌株.青霉索、四环素和环丙沙星的MIC50及MIC90均已超过耐药标准,尤以青霉素为甚,其MIC50及MIC90均超过耐药标准1、32倍.结论 淋球菌对大观霉素和头孢曲松的敏感性较高,可作为治疗的首选药物;对青霉素、四环素和环丙沙星耐药率较高,提示对淋病的治疗作用差.     

淋球菌流行株对5种抗生素敏感性分析

目的 检测2008年度临床分离的淋球菌对青霉素、四环素、大观霉素、头孢曲松和环丙沙星的敏感性,分析耐药菌株的流行特点.方法 采用琼脂稀释法测定菌株对5种抗生素的最小抑菌浓度(MIC),判断其敏感性并按WHO西太平洋地区淋球菌耐药性监测统一标准.用纸片酸度法检测产β-内酰胺酶淋球菌菌株.结果 107株淋球菌中,检出94株对青霉素耐药(87.9%),产β-内酰胺酶淋球菌43株(40.2%);四环素耐药率为88.8%,其中质粒介导高度耐四环素淋球菌(TRNG)63株(58.9%);环丙沙星耐药率81.3%;未发现对大观霉素和头孢曲松耐药菌株.青霉索、四环素和环丙沙星的MIC50及MIC90均已超过耐药标准,尤以青霉素为甚,其MIC50及MIC90均超过耐药标准1、32倍.结论 淋球菌对大观霉素和头孢曲松的敏感性较高,可作为治疗的首选药物;对青霉素、四环素和环丙沙星耐药率较高,提示对淋病的治疗作用差.     

Lipopolysaccharide structure and serum sensitivity of non-serogroupable Neisseria meningitidis

Bactericidal activities of normal human serum for non-serogroupable strains of Neisseria meningitidis were determined. In similar experiments with isolates of Neisseria gonorrhoeae from localized infections, strains with group I lipopolysaccharide (LPS) were uniformly serum resistant and those with group II were serum sensitive. We found no similar association between serum sensitivity of the meningococcal strains and their lipopolysaccharide groups determined by the same pyocin typing system used to classify the gonococcal isolates. Immune mouse sera raised against non-serogroupable meningococci of either LPS group I or II were bactericidal for non-serogroupable strains of the same LPS group and also cross-reactive for strains of the opposite group. They were not bactericidal for the majority (13/17) of the serogroupable strains tested. These findings suggest there are antigens, in addition to the LPS and capsules, that elicit some of the "natural" bactericidal antibodies to pathogenic meningococci.     

脑膜炎奈瑟氏菌对常用抗菌药物敏感性监测

本文就1966～1993年21个省市分离的218株A、B和C群脑膜炎奈瑟氏菌(Nm)对7种常用抗菌药物的敏感性进行了监测。在108株A群Nm中20株(18.5％)对SMZ耐药，其中17.3％的病人菌株，21.2％的带菌者菌株耐药；31株(28.7％)对ASP耐药。在101株B群Nm中40株(39.6％对SMZ耐药，其中43.3％的病人菌株和34.1％的带菌者菌株耐药，17株(16.8％)对ASP，10株(9.9％)对cF耐药。在9株c群Nm巾5株对SMZ，2株对ASP耐药。未发现Nm对Chl耐药。实验结果提示我们今后在流脑治疗和化学预防上应加强Nm对抗菌药物敏感性的监测，这有助于提高这些药物对流脑防治的效果。     

Antimicrobial susceptibilities of Neisseria gonorrhoeae strains representing five distinct resistance phenotypes.

The susceptibilities of 109 strains of Neisseria gonorrhoeae to penicillin G, tetracycline, amoxicillin-clavulanic acid, cefotetan, cefoxitin, ceftriaxone, ciprofloxacin, and fleroxacin were determined. The activities of cefmetazole, cefuroxime, cefixime, and ofloxacin were also determined against 62 of these strains. Strains represented penicillin-susceptible (Pen(s)) N. gonorrhoeae; penicillinase-producing N. gonorrhoeae (PPNG) possessing 2.9-, 3.05-, 3.2-, or 4.4-MDa beta-lactamase plasmids; strains with high-level, plasmid-mediated tetracycline resistance (TRNG); strains with plasmid-mediated resistance to penicillin and tetracycline; and strains with chromosomally mediated resistance to penicillin and tetracycline (CMRNG). Ceftriaxone, cefixime, and ciprofloxacin were the most active agents tested against all strains. Pen(s), TRNG, and PPNG strains possessing a 3.2-MDa beta-lactamase plasmid were more susceptible to amoxicillin-clavulanic acid, extended- and broad-spectrum cephalosporins, and quinolones than were either PPNG strains possessing a 2.9-, a 3.05-, or a 4.4-MDa beta-lactamase plasmid or CMRNG strains.