福氏痢疾杆菌2b血清型菌株基因组中SfII和SfX前噬菌体整合位点及排列方式研究

目的 研究福氏痢疾杆菌2b血清型菌株中SfII和SfX前噬菌体整合位点及排列方式.方法 根据2b血清型菌株基因组中SFII和SfX前噬菌体可能的整合位点及排列方式,设计引物,对50株2b血清型菌株进行PCR扩增,并对扩增产物测序,根据扩增和测序结果判断噬菌体的整合位点和排列方式.结果 在2b血清型菌株中,SfII和SfX前噬菌体前后相连,整合于宿主菌染色体proA和yaiC基因间的thrW tRNA基因上;以SfII在前,SfX在后,或SfX在前,SfII在后两种方式排列;而以后一种方式为主,在共50株检测菌株中,有49株为此方式.结论 福氏痢疾杆菌血清型相关噬菌体的整合位点及排列方式,对研究福氏痢疾杆菌血清型转换及血清型相关噬菌体的整合机制具有重要意义.     

福氏痢疾杆菌2b血清型菌株基因组中SfII和SfX前噬菌体整合位点及排列方式研究

目的 研究福氏痢疾杆菌2b血清型菌株中SfII和SfX前噬菌体整合位点及排列方式.方法 根据2b血清型菌株基因组中SFII和SfX前噬菌体可能的整合位点及排列方式,设计引物,对50株2b血清型菌株进行PCR扩增,并对扩增产物测序,根据扩增和测序结果判断噬菌体的整合位点和排列方式.结果 在2b血清型菌株中,SfII和SfX前噬菌体前后相连,整合于宿主菌染色体proA和yaiC基因间的thrW tRNA基因上;以SfII在前,SfX在后,或SfX在前,SfII在后两种方式排列;而以后一种方式为主,在共50株检测菌株中,有49株为此方式.结论 福氏痢疾杆菌血清型相关噬菌体的整合位点及排列方式,对研究福氏痢疾杆菌血清型转换及血清型相关噬菌体的整合机制具有重要意义.     

儿童122株福氏志贺氏菌菌型分布及耐药性分析

目的:了解儿童感染福氏志贺氏菌菌型分布及耐药性.方法:对2007～2011年在唐山市妇幼保健院就诊的≤14岁腹泻患儿粪便分离的福氏志贺氏菌122株,采用纸片扩散检测其抗菌药物的耐药性,最后对药敏结果进行分析.结果:122株福氏志贺氏菌以F2a为主,占65.6％.122株志贺氏菌属对14种抗生素的药敏结果呈不同程度的耐药现象,对氨苄西林耐药率高达100.0％,对复方磺胺、氨苄西林/舒巴坦、阿莫西林/克拉维酸耐药率分别为88.9％、88.6％和82.2％,对头孢曲松、头孢噻肟耐药率分别为74.7％、66.2％,对环丙沙星、氨曲南、左氧氟沙星耐药率分别为22.4％、22.3％和11.6％,对亚胺培南未发现耐药菌株.结论:儿童福氏志贺氏菌属对某些抗生素产生耐药,而耐药率逐渐呈上升趋势,临床医生应引起高度重视.     

福氏志贺菌O-抗原修饰及血清型转换机制研究进展

该项研究结果说明采用血清型转换噬菌体位点特异性整合系统修饰O-抗原血清型的方法, 可以有效介导外源基因进入细菌染色体的特异性位点, 而不会干扰宿主菌中任何重要基因的表达, 对疫苗的研究具有重要意义。     

Virulence profiling of Shigella flexneri and emergence of serotype 2b as a highly virulent shigellosis causing strain in Pakistan

Bacillary diarrhea caused by Shigella flexneri is mediated by various virulence factors which make it the leading agent of diarrhea in developing countries. Previously, a high prevalence of S. flexneri, associated with diarrhea has been reported in Pakistan but no data is available on their virulence profile. The present study reports for the first time analysis of various virulence factors among S. flexneri serotypes isolated from clinical (diarrheal stool) and non-clinical (retail raw foods and drinking water) sources. A total of 199 S. flexneri (clinical: 155, raw foods: 22, water: 22) belonging to various serotypes were subjected to virulence genes detection and virulence profiling. The most frequent virulence gene was found to be ipaH (100%), followed by sat (98%), ial (71.3%), set1B (65.8%) and set1A (38.7%). A high level of virulence was detected in serotype 2b as compared to other serotypes as 32.3% of all serotype 2b have the entire set of five virulence genes including ipaH (100%), ial (100%), sat (37.7%), set1A (89.3%), and set1B (100%). Seven different virulence gene profiles (V1 - V7) were detected and the most frequently observed to be V1 (ipaH+, ial+, sat+, set1A+, set1B+) followed by V3 (ipaH+, ial+, sat+, set1B+). The predominant virulence gene pattern in serotype 2b isolated from clinical and non-clinical samples were V1 and V3. Furthermore, about 32% strains belonging to serotype 2b contain the complete set of five virulence genes isolated from patients with high disease severity. In conclusion, the current finding revealed for the first times that serotype 2b was the most virulent strains in both clinical and non-clinical samples in Pakistan. In addition, the virulence of serotype 2b was well correlated with high disease severity.     

Identification of newly recognized serotype 1c as the most prevalent Shigella flexneri serotype in northern rural Vietnam

We investigated the identity of 37 Shigella flexneri strains that had previously been isolated from northern rural Vietnam (Son Tay Province) and described as untypable. Twenty-four isolates reacted with MASF 1c, a monoclonal antibody specific for S. flexneri serotype 1c. A further ten untypable isolates were found to be rough mutants (no longer expressing O-antigen) that were derived from serotype 1c strains. Pulsed-field gel electrophoresis demonstrated that these strains consisted of many different clones, indicating serotype 1c was well established in this region in the late 1990s. Serotype 1c was the most prevalent S. flexneri serotype isolated in the Son Tay Province, accounting for about 40% of S. flexneri isolates. Subsequent isolation of S. flexneri serotype 1c in this region and elsewhere in Vietnam confirmed that serotype 1c is of genuine importance in Vietnam.     

4株福志贺菌Ⅱ型不同生物学特性实验研究

[目的]探索福志贺菌Ⅱ型(Shigella flexnn2,F2)菌株间生物学关系，及时发现新菌型。[方法]用同批试剂，对4株福志贺菌Ⅱ型进行生化、噬菌体裂解、药敏及血清学凝集试验。[结果]4株福志贺菌生化反应几乎完全相同；噬菌体裂解试验结果亦完全一样。但药敏试验结果差异较大；血清学凝集结果亦有所不同。[结论]福志贺菌Ⅱ型不同菌株间对抗生素敏感性存在着较大差异；福志贺菌Ⅱ型还存在着新的菌型。     

临床分离 34 株志贺氏菌菌群分布及耐药性分析简

目的了解安徽省近期临床分离志贺氏菌群分布、耐药情况及产生耐药的主要机制,为全省细菌性痢疾的防治工作提供参考资料。方法应用血清凝集法检测志贺氏菌的血清型,K-B法检测志贺氏菌对17种抗生素的敏感性,双纸片扩散法检测超广谱β-内酰胺酶（ESBLs）,PCR法检测ESBL耐药基因型。结果分离的34株菌全部是福氏志贺氏菌,其中2a、1a、4c、4a和X变种分别占47.1%、26.5%、17.6%、2.9%和5.9%;34株菌对氨苄青霉素、四环素、氯霉素和磺胺甲基异恶唑/甲氧氨苄嘧啶的耐药率分别为：100%、97.1%、97.1%和91.2%,对哌拉西林/三唑巴坦和美罗培南的耐药率分别为：29.4%和0.0%;47.1%的志贺氏菌产ESBLs;TEM、SHV、CTX-M-2、CTX-M-14和CTX-M-15检出率分别为：26.5%、0.0%、0.0%、17.6%和26.5%。结论本次分离的志贺氏菌以福氏2a型为主,对常用抗生素耐药情况较严重,其耐药机制主要是产生TEM型和CTX-M-14,15型ESBLs。     

Effect of fermentation of Ghanaian maize dough on the survival and proliferation of 4 strains of Shigella flexneri

Fermented and non-fermented Ghanaian maize dough was seeded with approximately 10(7) colony forming units of 4 strains of Shigella flexneri which had been isolated from patients with dysentery. In the non-fermented maize dough (pH 6.2) the shigellae were detectable in large numbers for up to 24 h after exposure. In the maize dough that had been fermented for 3 d (pH 3.2) 3 strains were detectable in small numbers for up to 6 h after inoculation. Thereafter none was isolated. The fourth strain, though detectable for up to 24 h after inoculation, had its numbers reduced considerably. This suggests that traditional methods of food preparation using fermentation have important anti-diarrhoeal functions and the current decline in popularity of such food technologies in certain developing countries may increase the risk of childhood diarrhoea.     

福氏2c(新菌型)和福氏2a志贺菌生物学关系实验研究

目的：研究福氏志贺菌2c与2a之间的生物学关系。了解新菌型的生物学特性。方法：对前述2株菌进行生化试验、噬菌体裂解试验、药物敏感试验和血清凝集试验。结果：2株菌的生化反应、噬菌体裂解模式均相同。福氏志贺菌2c同时含有群抗原3，4和7，对乙基西羧霉素、庆大霉素、卡那霉素耐药，而福氏志贺菌2a则对以上3种药物敏感。结论：新发现的福氏志贺菌2c与福氏志贺菌2a在药物敏感性上存在较大的差异。