广州市2例人感染猪链球菌病的流行病学调查

目的查明广州市2例人感染猪链球菌病的感染来源、流行特征,为预防控制疫情提供依据。方法采用流行病学调查方法进行回顾性调查和现场调查,采集脑脊液标本进行细菌培养、分离,用PCR进行鉴定。结果患者均有明显的生猪接触史且首例患者手部有伤口,起病急,全身中毒症状明显,病程进展迅速,均为脑膜炎型。患者脑脊液分离培养出猪链球菌经生化和PCR检测结果为猪链球菌Ⅱ型,病人经及时治疗均痊愈出院。结论2例病例均为人感染猪链球菌病（Ⅱ型）实验室确诊病例,为散发疫情,相互间无流行病学关联,传播途径可能为接触被猪链球菌污染的生猪肉。     

深圳市2起人感染猪链球菌病疫情的流行病学调查

目的查明我市2起人感染猪链球菌病的感染途径和流行特征，为制定预防控制措施提供依据。方法开展流行病学调查，采集脑脊液标本，用血平板进行细菌培养、分离，用PCR鉴定。结果患者手部有外伤且有生猪肉接触史，临床上潜伏期短，病程进展迅速，均为脑膜炎型。患者脑脊液中分离的细菌经生化和PCR检测结果为猪链球菌Ⅱ型。病人经过及时抢救均脱离了危险。结论2起疫情为散发疫情，相互间无流行病学联系。传播途径为接触被猪链球菌污染的生猪肉经破损皮肤而传染。应加强卫生知识宣传和教育，提高肉食品加工人员的自我保护能力，同时要提高医务人员的诊治水平。     

一株副猪链球菌的鉴定及生物学特征分析

目的对从一患者脑脊液中分离的副猪链球菌菌株进行病原学鉴定, 并了解其生物学特征。方法对该菌株使用分离培养、生化鉴定、16S rRNA和管家基因recN基因分析、平均核苷酸一致性分析(ANI)、药敏实验、耐药基因、毒力基因分析等方法进行分析。结果该菌为革兰阳性球菌、在血平板上草绿色溶血, 经16S rRNA、recN基因及全基因组序列分析为副猪链球菌, 对多种抗生素敏感, 并携带有黏附类等多种毒力基因。结论副猪链球菌可导致人类感染, 可通过基因测序方法进行诊断。     

四川资阳猪源猪链球菌病病原的分离与鉴定

目的四川省部分地区发生的不明原因的猪源人畜共患病病原菌的分离与鉴定。方法采用普通RT-PCR和实时荧光PCR相结合的方法对流感和尼帕病毒的RNA进行检测，在Vero细胞和SPF鸡胚同时进行病毒分离，用血清平板对病料进行细菌分离，同时用革兰染色、生化试验、血清凝集试验和PCR进行鉴定，并对分离到的细菌进行药敏试验。结果排除了流感病毒和尼帕病毒感染的可能性。从病料组织中成功分离到3株链球菌，证实为猪链球菌Ⅱ型。通过对其毒力因子进行鉴定，结果发现溶菌酶释放蛋白（MRP）和细胞外蛋白因子（EF）均为阳性。进一步的药敏试验证实：分离菌株对氨苄青霉素、先锋霉素Ⅵ、羧苄青霉素、复方新诺明、头孢呋肟等抗菌药高度敏感。结论病原为猪链球菌Ⅱ型。     

广东省2例城市型人感染高致病性禽流感（H5N1）病例的流行病学调查

目的通过对2例城市人禽流感病例的流行病学调查、分析，探讨无直接病死禽暴露情况下的可能感染来源，为进一步防控禽流感提供科学依据。方法采用现场流行病学、血清学调查的方法；荧光定量PCR、ELISA、RT—PCR和应急监测等方法进行调查、诊断。结果2例感染高致病性禽流感病毒（H5NI）确诊病例未发现有明确病死禽接触史，但发病前到过甚至多次到过农贸市场；密切接触者中没有发生不明原因肺炎病例，未发现人一人传播证据。结论2例人感染高致病性禽流感病例均属城市型感染个案，非人传人病例，感染来源可能与农贸市场环境有关。     

2006年1至8月份我国克雅病监测病例分析

目的了解我国克雅病（Creutzfeldt-Jakob disease，CJD）的发病情况及分布特征。方法对2006年1至8月份我国克雅病监测网络获得的可疑CJD病例的l临床及流行病学资料进行分析；收集患者脑脊液及血液样品，利用Western Blot方法对脑脊液中14—3—3蛋白进行检测；利用PCR及测序方法对脚基因进行序列分析。结果共发现CJD临床诊断病例10例，疑似诊断病例8例。均为散发型CJD病例，病例的地理分布及职业没有明显的聚集性。发病年龄平均为60岁，男女比例接近1：1。首发症状中以快速进行性痴呆所占比例最多，占44％。临床诊断病例比疑似诊断病例出现更多的典型临床表现。结论我国监测到的CJD病例主要以散发型为主，地理、职业、男女比例以及平均年龄均符合散发型CJD的分布特点。     

27例结核性脑膜炎的脑脊液细胞学观察

结核性脑膜炎（简称结脑）是中枢神经系统常见的感染性疾病,其脑脊液细胞学改变具有一定的规律性特征,许事学者主张将脑脊液细胞学检查列为结脑的常规检查项目。本文对刀削结脑的脑脊液细胞学变化进行了观察,现总结报告如下。临床资料刀例给脑患者均为本科住院病人,其中男性19例,女性8例,年龄对一63岁,平均34．2岁,病程均在1个月以内。都有典型的脑膜炎临床症状和体征,有明确的结核病史或接触史,对抗密治疗均有效,部分病例结核杆菌培养或涂片检查呈阳性。本组病例均经异烟讲等治疗至少1个月以上,临床好转出院。检查方法常规腰椎…     

北京市2010年一起手足口病聚集性死亡疫情分析

目的 探讨北京市2010年一起EV71引起的手足口病聚集性死亡疫情处置中发现的防控薄弱环节.方法 对病例、密切接触者和病例生活环境进行现场流行病学调查并采样,开展病毒分离和RT-PCR检测,并对流行株进行VP1基因测序,结果用描述流行病学方法进行分析.结果 该起聚集性死亡疫情由至少两个EV71病毒链引起,两名患儿死亡.死亡患儿有共用餐具史及延迟就医现象.两名死亡患儿的儿童直接接触者咽拭子阳性率为66.67％,粪便阳性率为42.86％;成人直接接触者咽拭子阳性率为25.00％,粪便阳性率为33.33％;间接接触者咽拭子及粪便阳性率均为零.结论 应加强重症病例早期预警指征、安全用药常识及一般卫生知识的宣教,以减少手足口病的传播,降低病死率.     

503例残留麻痹急性弛缓性麻痹病例病原流行病学特征分析

目的 分析广东省1994-2007年间残留麻痹病例的病原流行病学特征.方法 对1994-2007年广东省503例残留麻痹病例的粪便标本进行病毒分离、血清型鉴定和脊髓灰质炎(脊灰)病毒型内鉴定,并使用统计学方法,综合分析病原学结果与残留麻痹病例的免疫史、性别、年龄等流行病学资料之间的关系.结果 收检了503例残留麻痹病例的粪便标本,其中150例分离到脊灰病毒(PC),均为疫苗类似株,59例分离到非脊灰肠道病毒(NPEV),PV和NPEV的年度分离率分别在18.92%.47.06%和4.17%～25.00%之间浮动.PV分离率随年龄组的增大而降低,0岁组最高,为61.11%;0～2次免疫的病例的PV分离率远高于全程免疫者,差异有统计学意义;残留麻痹病例中的PV和NPEV分离率均高于无残留麻痹的病例.结论 1994-2007年广东省未发现由脊灰野病毒引起的残留麻痹病例,2岁以下年龄组和0～1剂次免疫者中的PV分离率与残留麻痹有相关性.NPEVs也可能是儿童出现残留麻痹病例的病原之一.     

一起诺如病毒感染性腹泻爆发的流行病学调查

目的分析深圳市某区一起诺如病毒感染性腹泻爆发的流行病学特征,为防治诺如病毒感染性腹泻提供科学依据。方法采用病例对照研究相关方法开展此次疫情调查,比较病例与对照之间不同危险因素的暴露比例,采用RT—PCR检测诺如病毒抗原。结果共报告46例诺如临床诊断病例。病例分布在该片区的3个单位,平均罹患率为12．64％。在危险因素的单因素分析中,只有A单位中饭前用自来水洗碗（0R=7．14．95％CI：1．83-27．88）、接触病人（OR=7．64,95％CI：1．33～43．76）结果具有统计学意义。在20份患者肛拭子样本中,有15份分离到诺如病毒。结论此宗诺如病毒感染性腹泻爆发可能是由于水污染和接触病人导致传播的。采取加强饮食卫生管理、隔离治疗病人及带菌者、整改清洁饮用水管道等措施后疫情中止。     

Streptococcus suis infection.

A recent outbreak of Streptococcus suis infection associated with the slaughter, preparation or consumption of pigs in Sichuan, China has led to concerns that similar outbreaks could occur in other Asian countries. Although the pig farming industry is flourishing in Taiwan, reports of S. suis infection remain rare. We report 2 cases of S. suis meningitis successfully treated with ceftriaxone and penicillin. Previous reports of S. suis infection from the English literature are reviewed and the clinical data of cases reported in Asian and European countries are summarized. In Europe, there was good correlation between clinical disease and porcine contact, while few cases in Asia reported this association. Meningitis remained the most common presentation of infection in both areas (84.6% and 75.2%, respectively), followed by sepsis (15.4% and 18.6%, respectively), which had a higher mortality rate, particularly for splenectomized patients. Other clinical presentations included enteritis, arthritis, endocarditis, pneumonia, spondylodiscitis, endophthalmitis, uveitis and peritonitis. Deafness was a distinct sequelae (50.5% in Europe and 51.9% in Asia) after recovery from S. suis infection, especially in patients with meningitis. Not all commercial identification systems for streptococci could offer adequate speciation for S. suis. When viridans group streptococci are isolated from patients with meningitis and sepsis, prompt and correct identification of isolates to the species level should be performed, especially in areas with a high prevalence of S. suis diseases.     

Streptococcus suis infections in birds

Four cases of Streptococcus suis infection were diagnosed in psittacine birds and four others in zebrafinches, bullfinches, canaries and a duck. The main clinical and pathological manifestation was septicaemia with multiple sudden deaths in nestlings, young and adults. Other cases were solitary, with evidence for secondary involvement of S. suis. Four serotypable strains all belonged to serotype 9.     

Development of Rapid Serotype-Specific PCR Assays for Eight Serotypes of Streptococcus suis

Streptococcus suis is an emerging zoonotic pathogen causing severe infections in pigs and humans. Thirty-three serotypes of S. suis have been identified using serum agglutination. The capsular polysaccharides synthesis (cps) locus is usually conserved among different strains of the same serotype. The cps loci of 15 serotypes have been sequenced, while the loci of the other serotypes remain unknown. In the present study, two to six serotype-specific genes of each of eight serotypes, i.e., serotypes 3, 4, 5, 8, 10, 19, 23, and 25, were identified using cross-hybridization with 93 nucleic acid probes specific to genes in the cps locus, and serotype-specific PCR assays for rapid and sensitive detection of the eight serotypes were then developed. The PCR typing results of the 148 serologically typeable isolates were completely consistent with agglutination results. Furthermore, some autoagglutinating, acapsular, and multiagglutinating strains which could not be differentiated by traditional serum agglutination assays were positive in the PCR assays. Use of the PCR assays with clinical tonsillar specimens showed that the assays are sensitive and able to identify samples with autoagglutinating isolates. To our knowledge, this is the first study to identify the serotype-specific genes of the eight Streptococcus suis serotypes and develop rapid and sensitive PCR assays for the eight serotypes which can be identified only by serum agglutination.     

Phagocytosis and killing of Streptococcus suis by porcine neutrophils

Streptococcus suis serotype 2 is an important swine pathogen responsible for diverse infections, mainly meningitis. Virulence factors and the pathogenesis of infection are not well understood. Neutrophils may play an important role in the pathogenesis of infection given that infiltration by neutrophils and mononuclear cells are frequently observed in lesions caused by S. suis. The objective of this work was to study the interactions between S. suis serotype 2 and porcine neutrophils. Results showed that suilysin is toxic to neutrophils and this could help S. suis evade innate immunity. Moreover, suilysin appears to affect complement-dependent killing by decreasing the opsonization of S. suis and the bactericidal capacity of neutrophils. Our results confirm that capsule polysaccharide protects S. suis against killing and phagocytosis by neutrophils. We also showed that the presence of specific IgG against S. suis serotype 2 promoted killing by neutrophils, indicating that the induction of a strong humoral response is beneficial for clearance of this pathogen.     

Diagnosis and surveillance of herpes simplex virus infection of the central nervous system

Herpes simplex viruses (HSV) are responsible for neurological disorders that require rapid diagnostic methods and specific antiviral therapy. During 1997, 1431 cerebrospinal fluid samples (CSF) collected from 1339 patients with neurological disorder presentations were processed for HSV detection. Eleven patients were positive for HSV, seven presenting with encephalitis (6/7 due to HSV1) and 4 with aseptic meningitis (4/4 due to HSV2). The incidence of HSV encephalitis was 2.33 cases / 10(6) inhabitants/year. Among encephalitis (HSV encephalitis) cases, 1 patient died due to the late implementation of antiviral therapy, and sequelae were observed in 4 cases. No sequelae were observed in aseptic meningitis cases. Four HSV encephalitis cases were monitored by PCR detection in CSF. Despite acyclovir therapy, PCR remained positive in CSF up to 20 days in 2 cases. This result suggest that the antiviral treatment for HSV encephalitis should be monitored by PCR detection of HSV in CSF.     

Prevalence of tuberculous meningitis in Niamey's Hospital, Niger

Tuberculosis is hyperendemic in Niger. In Niamey between June 2002 and May 2004, 996 cerebro-spinal fluids (CSF) collected from meningitis suspected patients have been analysed by PCR for the detection of Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae: the aetiologic diagnosis was obtained for 208 cases (20.9%). The Mycobacterium tuberculosis PCR assay performed on the negative samples was positive for 4 CSF: 0.4% prevalence among suspected cases of meningitis or 1.9% among confirmed bacterial meningitis.     

Comparison of broad-range bacterial PCR and culture of cerebrospinal fluid for diagnosis of community-acquired bacterial meningitis

Appropriate, rapid and reliable laboratory tests are essential for the diagnosis and optimal antibiotic therapy of acute bacterial meningitis. Broad-range bacterial PCR, combined with DNA sequencing, was compared with culture-based methods for examining cerebrospinal fluid (CSF) samples from patients with suspected meningitis. In total, 345 CSF specimens from 345 patients were analysed, with acute community-acquired bacterial meningitis being diagnosed in 74 patients. The CSF of 25 patients was positive by both PCR and culture; 26 patients had CSF specimens positive by PCR only, and 14 patients had specimens positive by culture only. The sensitivity of PCR and culture for clinically relevant meningitis was 59% (44/74) and 43% (32/74), respectively, while the specificity was 97% (264/271) and 97% (264/271), respectively. The commonest bacterial rRNA gene sequences detected by PCR only were those of Streptococcus pneumoniae and Neisseria meningitidis (n = 12). PCR failed to detect the bacterial rRNA gene in seven specimens from patients with symptoms compatible with acute bacterial meningitis. Overall, the results demonstrated that PCR in conjunction with sequencing may be a useful tool in the diagnosis of bacterial meningitis. PCR is particularly useful for analysing CSF from patients who have been treated with antibiotics before lumbar puncture.     

Identification of the gene encoding a 38-kilodalton immunogenic and protective antigen of Streptococcus suis

In our continued effort to search for a Streptococcus suis protein(s) that can serve as a vaccine candidate or a diagnostic reagent, we constructed and screened a gene library with a polyclonal antibody raised against the whole-cell protein of S. suis type 2. A clone that reacted with the antibody was identified and characterized. Analysis revealed that the gene encoding the protein is localized within a 2.0-kbp EcoRI DNA fragment. The nucleotide sequence contained an open reading frame that encoded a polypeptide of 445 amino acid residues with a calculated molecular mass of 46.4 kDa. By in vitro protein synthesis and Western blot experiments, the protein exhibited an electrophoretic mobility of approximately 38 kDa. At the amino acid level the deduced primary sequence shared homology with sequences of unknown function from Streptococcus pneumoniae (89%), Streptococcus mutans (86%), Lactococcus lactis (80%), Listeria monocytogenes (74%), and Clostridium perfringens (64%). Except for strains of serotypes 20, 26, 32, and 33, Southern hybridization analysis revealed the presence of the gene in strains of other S. suis serotypes and demonstrated restriction fragment length differences caused by a point mutation in the EcoRI recognition sequence. We confirmed expression of the 38-kDa protein in the hybridization-positive isolates using specific antiserum against the purified protein. The recombinant protein was reactive with serum from pigs experimentally infected with virulent strains of S. suis type 2, suggesting that the protein is immunogenic and may serve as an antigen of diagnostic importance for the detection of most S. suis infections. Pigs immunized with the recombinant 38-kDa protein mounted antibody responses to the protein and were completely protected against challenge with a strain of a homologous serotype, the wild-type virulent strain of S. suis type 2, suggesting that it may be a good candidate for the development of a vaccine that can be used as protection against S. suis infection. Analysis of the cellular fractions of the bacterium by Western blotting revealed that the protein was present in the surface and cell wall extracts. The functional role of the protein with respect to pathogenesis and whether antibodies against the antigen confer protective immunity against diseases caused by strains of other pathogenic S. suis capsular types remains to be determined.