Occurrence of Salmonella Enteric Serovar Typhi Antibodies among Blood Donors in Ghana

Background: Donated blood contaminated with S. Typhi can cause post-transfusion sepsis. This study aimed to determine the correlation between some risk factors of typhoid fever and seroprevalence of antibodies against S. Typhi among blood donors. Methodology: Following informed consent, socio-demographic and information on risk factors of typhoid infection was obtained using pre-structured questionnaires from 400 apparently healthy blood donors at the Tema General Hospital. Blood was also collected for serology and cultured for identification of pathogens by standard bacteriological method. Results: Blood culture did not reveal any S. Typhi isolate out of the tested 400 (348 males and 52 females) samples from apparently healthy blood donors. However, IgM and IgG antibody seroprevalence of 9.3% and 3.5% were detected. Age group of 17 - 24 years was the highest risk group, persons with a history of typhoid infection, and sources of drinking water were major risk factors for typhoid infection. It was also observed that prevalence of IgM was highest among new donors (62.2%), but lower in donors with a history of 1 to 3 blood donations (32.4%) and least among regular donors (>3 donations (5.4%)). In addition, typhoid prevention awareness and typhoid knowledge (knowledge about typhoid transmission) among the donors were poor (4.3% and 5.9% respectively). Conclusions: This study has shown an overall seroprevalence of 9% and 3.5% for IgM and IgG antibodies respectively among blood donors in the Tema area in Ghana. We advocate for the mandatory screening of donor units intended for transfusion for S. Typhi. Furthermore, there is an urgent need for the health education of all persons in Ghana on preventive measures and the spread of S. Typhi.

A Review of <i>Staphylococcus aureus</i>and the Emergence of Drug-Resistant Problem

There are various bacteria living in this world. The most common one is Staphylococcus aureus. Almost everyone has heard of it. It is easy to find their habitats, such as hospitals, homes, parks, schools etc. Some of them are difficult to be eliminated because of drug-resistant mutations. Hence, lots of researchers devoted their efforts to eliminate them. This review illustrates the characteristics of the Staphylococcus aureus and the main threat of their drug-resistant strains, especially methicillin-resistant S. aureus. What’s more, the article also highlights the plight in the drug development.

Isolation of Multi-Drug Resistant (MDR) and Extensively Drug Resistant (XDR) <i>Salmonella typhi</i>from Blood Samples of Patients Attending Tertiary Medical Centre in Dhaka City, Bangladesh

Objective: Almost all year round occurrence of typhoid fever remains a major public health issue in Bangladesh. In recent years, there has been a significant rise in the prevalence of multi-drug resistance Salmonella typhi in Dhaka city. The major objective of this study was to observe the prevalence of multi-drug and Extended drug-resistant patterns of typhoidal Salmonella typhi among the patients attending a tertiary medical center by conventional culture and serologic test. Materials and Methods: Blood was collected by syringe and equally divided between aerobic & anaerobic BacT Alert bottle, 10 mL for paediatrics. Post isolation Salmonella strains were identified and were tested for antibiotic resistance. Results: A total of 600 blood samples of typhoid suspected patients were tested, where 32.5% came out positive, which were identified as Salmonella typhi. These isolates were susceptible to carbapenem drugs but highly resistant to Fluoroquinolones and Aminoglycosides antibiotics. Discussion: It was seen that 73.23% of isolates among male patients were extensively drug-resistant (XDR) meaning that isolates were sensitive against only one or two antibiotics while in the female it was 58.46%. Isolates from Female patients showed higher multi-drug resistant (MDR) (26.15%) isolates resistance to multiple antibiotics in comparison to isolates from the male (16.54%). 87.19% of the strains showed high drug resistance (XDR and MDR). Conclusion: The emergence of XDR and MDR strains of S. typhi in recent years is becoming a significant threat. Although no PAN-Drug resistance (resistant against all tested drugs) was observed in the current study, a high level of XDR and MDR isolates are indicating that the scenario might take place sooner than later.

伤寒沙门氏菌SOD的提取及抗原性研究

经硫酸铵分级沉淀，ＤＥＡＥ纤维素柱层析提取了伤寒沙门氏菌ＳＯＤ。提取后酶的比活性为３２７０Ｕ／ｍｇ，经聚丙烯酰胺凝胶电泳，蛋白质染色及酶活性染色显示提取的ＳＯＤ达到了电泳纯。酶活性染色法和原子吸收分光光度法测定结果表明提取的ＳＯＤ为Ｆｅ－ＳＯＤ。双向琼脂扩散试验结果显示抗伤寒沙门氏菌Ｆｅ－ＳＯＤ血清与牛红细胞ＳＯＤ不形成沉淀线，提示伤寒沙门氏菌Ｆｅ－ＳＯＤ与牛红细胞ＳＯＤ无交叉反应，抗体对酶活性抑制试验结果显示抗Ｆｅ－ＳＯＤ血清可抑制伤寒沙门氏菌及鼠伤寒沙门氏菌的Ｆｅ－ＳＯＤ和Ｆｅ／Ｍｎ－ＳＯＤ活性，对Ｍｎ－ＳＯＤ活性无抑制作用，说明伤寒沙门氏菌和鼠伤寒沙门氏菌的ＳＯＤ之间有共同抗原，也提示ＳＯＤ的辅基似乎决定了其抗原特异性。

鼻腔接种伤寒杆菌Fe-SOD的抗体应答及对鼠伤寒杆菌攻击的免疫保护作用

目的 探讨鼻腔接种伤寒杆菌Fe SOD后血液和粘膜系统的抗体应答及免疫保护作用。方法 用IL - 1作为佐剂 ,将伤寒杆菌Fe SOD经鼻腔接种小鼠 ,检测小鼠血液及肠液中的抗体应答 ,并用鼠伤寒杆菌攻击小鼠 ,观察小鼠的存活情况 ,以确定免疫保护作用。结果 当用IL - 1作为佐剂时 ,经鼻腔接种伤寒杆菌Fe SOD的小鼠血液和肠液中可产生高水平特异性IgG和IgA ;而腹腔注射仅在血液中产生高水平特异性IgG。另外发现经鼻腔接种伤寒杆菌Fe SOD的小鼠在 2LD50 鼠伤寒杆菌攻击后 ,3d和 7d的存活率均明显高于对照组 (P <0 0 5 ) ,且以 5LD50 鼠伤寒杆菌攻击时 ,小鼠 7d的存活率明显高于对照组 (P <0 0 1)。结论 结果说明伤寒杆菌Fe SOD经鼻腔接种后可引起小鼠粘膜系统和血液中的抗体应答 ;对鼠伤寒杆菌的攻击可产生一定的免疫保护作用 ,也进一步说明了Fe SOD是沙门菌的共同保护性抗原。

Fis对伤寒沙门菌基因表达的系统调节作用

目的:探讨伤寒沙门菌调节因子fis对基因表达的系统调节作用。方法:用自杀质粒介导的同源重组方法制备伤寒沙门菌fis基因缺陷变异株,用脉冲场凝胶电泳分析fis缺陷变异株的基因组结构。利用伤寒沙门菌全基因组DNA芯片分析技术,比较伤寒沙门菌野生株和fis基因缺陷变异株的基因表达谱差异。用重组载体pBADfis回补fis缺陷变异株,选择部分差异表达基因进行qRT-PCR验证,用半固体平板培养观察野生株、fis缺陷变异株和回补株的动力。结果:fis基因缺陷变异株含有二相鞭毛素编码基因的线性质粒缺失,且动力消失;基因表达谱比较分析结果表明,伤寒沙门菌fis基因缺陷变异株在对数生长期94个基因出现表达差异;qRT-PCR分析所选基因表达的结果与芯片分析结果相符;fis缺陷变异株在回补fis基因后,动力及差异表达基因都获得明显恢复。结论:Fis在伤寒沙门菌中对动力、侵袭及多种代谢相关基因的表达发挥重要调节作用。

脉冲凝胶电泳分型在伤寒暴发中的应用

目的:探讨深圳市某区伤寒暴发在不同厂区,不同来源的伤寒沙门菌之间的遗传相关性,建立分子流行病学研究,进行同源性分析,并与表型分型比较。方法:对深圳市某街道社区10个工厂的伤寒患者分离的28株伤寒沙门菌,根据不同厂区、不同来源的伤寒菌株,采用传统的生化分型、血清学分型,肥达反应,药物敏感分型,荧光PCR及脉冲场凝胶电泳(PFGE)分子生物学分型的技术进行研究。结果:从93例发热现症病人的血和粪便中分离出28株伤寒沙门菌,肥达反应阳性(“O”≥1∶80;“H”≥1∶160;)59例,分离出伤寒沙门菌患者中,肥达反应阳性19例。从伤寒沙门菌菌株中抽取4个工厂患者中分离的11株伤寒沙门菌和1株乙型副伤寒沙门菌,进行了荧光PCR和脉冲场凝胶电泳(PFGE)全基因DNA指纹图谱分析,12株伤寒沙门菌的指纹图谱完全相同,有高度的同源性。对12株伤寒沙门菌荧光PCR检测均呈阳性,28株伤寒沙门菌生化表型相同,血清学分型相同,药敏结果有差异,肥达实验抗体滴度与健康人群比较,差异有统计学意义。结论:生化表型和血清学分型不能进行同源性分析,而通过脉冲场凝胶电泳(PFGE)全基因DNA指纹图谱分析,可追溯其同源性,通过12株伤寒菌株的PFGE分型图谱分析,菌株之间有高度的同源性,确认是由相同病原菌引起的一宗伤寒疫情。

小鼠肠上皮内淋巴细胞在粘膜免疫应答中的形态学研究

采用免疫组织化学和电镜方法，观察了ＢＡＬＢ／ｃ小鼠灌服伤寒杆菌后回肠及集合淋巴小结圆顶区肠上皮内淋巴细胞（ｉｎｔｒａｅｐｉｔｈｅｌｉａｌｌｙｍｐｈｏｃｙｔｅ，ＩＥＬ）的形态和分布特征，以探讨ＩＥＬ在抗原诱导下的粘膜免疫应答中的作用。经免疫组织化学方法证实灌服伤寒杆菌后回肠及集合淋巴小结圆顶区肠上皮内含Ｂ和Ｔ两种淋巴细胞，以Ｂ淋巴细胞为主；电镜下可见上皮内淋巴细胞主要由小和中等淋巴细胞组成，且后者有两种形态。一种细胞器较少，与上皮微绒毛之间有紧密接触。另一种细胞器丰富，内质网呈扩张状态。同时观察到ＩＥＬ有的位于上皮细胞内，有的位于相邻的上皮细胞间隙内。本研究提示，小肠上皮不仅为粘膜免疫效应部位，而且也是免疫诱导部位。提示伤寒杆菌能诱导淋巴细胞向小肠上皮和圆顶区上皮迁移，且圆顶区上皮比小肠上皮更易接受抗原刺激。

1998-2000年沙门菌属耐药性变迁

目的 :调查 1998— 2 0 0 0年伤寒、副伤寒和非伤寒沙门菌耐药性的变迁。方法 :纸片扩散法 (K B法 ) ,依照美国临床实验室标准化委员会制定的 2 0 0 0年版的标准。结果 :1.1998— 2 0 0 0年伤寒和副伤寒沙门菌 2 37株 (其中伤寒沙门菌 191株 ,甲、乙、丙副伤寒沙门菌 46株 )对临床常用抗菌药的耐药性变化不大 ;而 12 2株非伤寒沙门菌则增长较快 ,其中对氨苄西林的耐药率从 1998年的 2 6 .6 %增加到 2 0 0 0年的 46 .3%,复方磺胺甲唑从 2 0 .0 %到 5 9.3%,环丙沙星从 10 .0 %到 2 9.6 %。2 0 0 0年氯霉素和四环素的耐药率分别为 31.5 %和 5 0 .0 %。 2 .在非伤寒沙门菌分离株中 ,肠炎沙门菌和鼠伤寒沙门菌为主要血清型。 3.此次分析中发现 3株多重耐药谱为ACTStCp的鼠伤寒沙门菌。 结论 :除复方磺胺甲唑外 ,伤寒、副伤寒沙门菌对临床常用抗菌药仍很敏感。非伤寒沙门菌对临床常用抗菌药耐药率逐渐增加 ,加强其耐药性监测是非常必要的。

耐药伤寒流行菌株的耐药谱及质粒图谱分析

1989～1990年从四川达县地区分离的63株流行性伤寒沙门氏菌中,55株(87.3％)为多重耐药菌,仅对头孢呋肟、丁胺卡那霉素和新型氟喹诺酮类抗菌药物敏感。多重耐药的类型以SMKMABPCCPTCSUGMCET和SMKMABPCCPTCSUCET为主。同期收集的散发性伤寒沙门氏菌43株,有9株(21％)为多重耐药菌。质粒图谱显示,多重耐药菌都有1条分子量约为98Md的大质粒。其中1株还带有 3条质粒带。质粒消除试验证明,98Md的大质粒与多重耐药性有关。

重庆地区沙门氏菌耐药变迁及临床疗效观察

本文报道了重庆地区1984～1988年沙门氏菌对32种抗菌药的敏感度试验、30年来的耐药变迁及伤寒与耐药伤寒的临床疗效观察。表明耐药伤寒杆菌对常用于治疗伤寒的抗生素如氯霉素、SMZ/TMP、氨苄青霉素及其它药物产生了不同程度的耐药性。

伤寒临床表现及抗菌素反应观察

目的 评价伤寒临床表现和伤寒沙门菌对各种抗菌素的反应。方法 对1996～2001年住院的44例成人伤寒患者进行了回顾性分析。结果 伤寒沙门菌对氯霉素、复方新诺明、氨苄青霉素、阿莫西林耐药性很高，对环丙沙星有一定耐药性。结论 在伤寒治疗中不要滥用药物，应通过药敏试验来选择适当的抗菌素以阻止伤寒沙门菌耐药株出现。

江苏省M_1型伤寒沙门氏菌的分子流行病学特征

选择江苏省各地 1988～ 1997年分离到的 2 6株M1型伤寒菌进行AP -PCR分析。结果 2 6株M1型伤寒菌被引物 2 2 732、2 2 733和 2 2 734共同划分为 7种不同的基因型别。将菌株的基因型别与流行病学资料分析相结合 ,发现在江苏省伤寒呈现高强度流行的 80年代末至 90年代初 ,M1型菌株呈现高度的基因多态性表现 ,而在江苏省伤寒流行强度较低的近几年 ,M1型菌株的基因多态性表现则明显减弱。

PmrA对伤寒沙门菌高渗应激后期基因表达调节初探

目的:探讨伤寒沙门菌调节因子PmrA在高渗应激后期对基因表达调节的影响。方法:应用自杀质粒介导的同源重组方法制备伤寒沙门菌pmrA基因缺陷变异株;利用伤寒沙门菌全基因组芯片分析技术,比较伤寒沙门菌野生株和pmrA基因缺陷变异株在高渗应激后期的基因表达谱差异,并选择部分差异表达基因进行RT-RCR验证。结果:经PCR及序列分析证实,伤寒沙门菌pmrA基因缺陷变异株制备成功;基因表达谱比较分析结果表明伤寒沙门菌pmrA基因缺陷变异株在高渗应激后期有81个基因表达上调,有22个基因表达下调。结论:PmrA在伤寒沙门菌高渗应激后期的基因表达调节中发挥重要作用。

Molecular Analysis and Identification of Virulence Gene on pR_(ST98) from Multi-Drug Resistant Salmonella typhi

pR_(ST98) is a large and conjugative resistant plasmid(R plasmid)of 98.6 mega-dalton from multi-drug resistant Salmonella typhi(S.typhi),which was classified to incompatibility group C(Inc C).It has been found that pR_(ST98) made its host bacteria not only antibiotic resistant but also more virulent.In this study we explored the possibility of plasmid pR_(ST98) in S.typhi carrying the Salmonella plasmid virulence gene-spv.The plasmid pR_(ST98) was isolated, purified and then digested by nine restriction endonucleases to make the plasmid enzyme profile.Spv-specific PCR and Southern blot were applied to identify the virulence gene on pR_(ST98).The amplified spv fragments spvR and spvB were cloned into pGEM-T EASY and then the DNA sequences were analysed.The fragments of pR_(ST98) digested by endonucleases Bgl Ⅱ,Pst Ⅰ and Sac Ⅱ were identified,which may be useful for molecular analysis and further epidemiological surveillance of pR_(ST98).The results of PCR and Southern blot showed that spv homologous genetic sequence which had been found in all pathogenesis Salmonella spp.except S.typhi was also presented on pR_(ST98).The ORF of spvR and spvB of pR_(ST98) were 894 bp and 1,776 bp,respectively.They have more than 99% homology with that of spvR and spvB on virulence plasmid in S.typhmurium.The genotype research on pR_(ST98) revealed that there is a plasmid carrying genes responsible for drug resistance and virulence in S.typhi.This is the first report for such kind chimerical plasmid in S.typhi.Cellular & Molecular Immunology.2005;2(2):136-140.

伤寒沙门氏菌特异性θ诊断血清的应用

应用新的特异性θ诊断血清和传统商品血清与434株伤寒沙门氏菌地方株作玻片凝集平行试验，两者诊断符合率为100％。θ血清与0．1％酚琼脂斜面上的所有伤寒沙门氏菌呈迅速清晰的阳性凝集反应。鉴于θ血清与大多数D群沙门氏菌不凝集，因此，大大提高诊断的正确性。

Antibiotic resistome of Salmonella typhi:molecular determinants for the emergence of drug resistance

Resistome is a cluster of microbial genes encoding proteins with necessary functions to resist the action of antibiotics.Resistome governs essential and separate biological functions to develop resistance against antibiotics.The widespread clinical and nonclinical uses of antibiotics over the years have combined to select antibiotic-resistant determinants and develop resistome in bacteria.At present,the emergence of drug resistance because of resistome is a significant problem faced by clinicians for the treatment of Salmonella infection.Antibiotic resistome is a dynamic and ever-expanding component in Salmonella.The foundation of resistome in Salmonella is laid long before;therefore,the antibiotic resistome of Salmonella is reviewed,discussed,and summarized.We have searched the literature using PubMed,MEDLINE,and Google Scholar with related key terms(resistome,Salmonella,antibiotics,drug resistance)and prepared this review.In this review,we summarize the status of resistance against antibiotics in S.typhi,highlight the seminal work in the resistome of S.typhi and the genes involved in the antibiotic resistance,and discuss the various methods to identify S.typhi resistome for the proactive identification of this infection and quick diagnosis of the disease.

伤寒、甲、乙、丙型副伤寒沙门菌多重荧光PCR方法的评估及临床应用

目的建立和评估多重荧光PCR方法快速鉴定伤寒、甲、乙、丙型副伤寒沙门菌的方法,并应用于临床血培养样品的检测。方法收集留取医院的可疑伤寒患者的血培养标本,用多重实时荧光PCR法和传统分离培养法同时进行分离鉴定,分析比较双盲实验结果,评价多重实时荧光PCR方法的灵敏度、特异度等检测性能指标。结果共检测临床样本538例,多重荧光PCR法检出阳性218例,比传统培养法多检出6例;阴性320例,与传统培养法一致。以传统检测方法为金标准,多重荧光PCR方法的灵敏度为100%,特异度为98.2%。结论建立的多重荧光PCR检测方法操作简便,可快速、特异、灵敏地检测出伤寒、甲、乙、丙型副伤寒沙门菌,可以应用于临床标本的早期快速分型诊断,提升重大传染病的应急处置能力和监测能力。

Co-administration of rlpaB domain of Shigella with rGroEL of s. Typhi enhances the immune responses and protective efficacy against Shigella infection

Shigella species cause severe bacillary dysentery in humans and are associated with high morbidity and mortality. The Invasion plasmid antigen （IpaB） protein, which is conserved across all Shigella spp., induces macrophage cell death and is required to invade host cells. The present study evaluates the immunogenicity and protective efficacy of the recombinant （r） domain region of IpaB （rlpaB） of S. flexneri, rlpaB was administered either alone or was co-administered with the rGroEL （heat shock protein 60） protein from S. Typhi as an adjuvant in a mouse model of intranasal immunization. The IpaB domain region （37 kDa） of S. flexneriwas amplified from an invasion plasmid, cloned, expressed in BL21 Escherichia colicells and purified. Immunization with the rlpaB domain alone stimulated both humoral and cell-mediated immune responses. Furthermore, robust antibody （IgG, IgA） and T-cell responses were induced when the rlpaB domain was co-administered with rGroEL. Antibody isotyping revealed higher IgG 1 and IgG2a antibody titers and increased interferon-gamma （IFN-γ） secretion in the co-administered group. Immunization of mice with the rlpaB domain alone protected 60%-70% of the mice from lethal infection by S. flexneri, S. boydiiand S. sonnei, whereas co-administration with rGroEL increased the protective efficacy to 80%-85%. Organ burden and histopathological studies also revealed a significant reduction in lung infection in the co-immunized mice compared with mice immunized with the rlpaB domain alone. This study emphasizes that the co-administration of the rlpaB domain and rGroEL protein improves immune responses in mice and increases protective efficacy against Shigella infection. This is also the first report to evaluate the potential of the GroEL （Hsp 60） protein of S. Typhi as an adjuvant molecule, thereby overcoming the need for commercial adjuvants.

伤寒杆菌耐药质粒pRST98介导细菌毒力的研究

目的 研究伤寒杆菌耐药质粒pRST98能否介导细菌毒力。方法 将pRST98导入鼠伤寒杆菌低毒株RIA ,经口和腹腔感染小鼠 ,测定半数致死量 (LD50 ) ;口饲细菌后检测在体内播散、繁殖及引起脏器的组织学改变 ;在体外对其进行细胞的粘附和侵袭试验。分别用含pRST98的野生伤寒杆菌、消除pRST98的突变体菌株及pRST98再重新导入突变体的菌株 ,研究对人、兔及豚鼠血清杀菌的抵抗力。结果 导入pRST98的鼠伤寒杆菌口服和腹腔注射组LD50 比阴性对照分别降低约 70 0倍和75倍 ;在小鼠肠系膜淋巴结、脾和肝脏内增殖 (P <0 .0 5 )并引起脏器严重病变 ;但在体外不影响鼠伤寒杆菌对HEp 2、CHO和HeLa细胞的粘附和侵袭。携带pRST98的伤寒杆菌在血清中的抵抗力显著高于无此质粒的菌株 (P <0 .0 5 )。结论 伤寒杆菌耐药质粒pRST98不但介导对药物的抗性 ,同时还能使宿主菌的毒力增强。