一起由两种罕见血清型副溶血性弧菌引起食物中毒事件分析

目的 分析一起由两种罕见血清型混合感染引起的副溶血性弧菌食物中毒病原学的检测结果,为食物中毒病原学检查途径提供依据。方法 对一起在龙门县人民医院就诊食物中毒事件的9例患者采集其肛拭子样本,参照《食品微生物学检验副溶血性弧菌检验》( GB 4789.7—2013) 等标准进行病原学分析鉴定。结果 本次事件出现临床症状者9例,其中≤20岁2例,20~<40岁1例,40~<60岁4例,≥60岁2例;9份肛拭子样本检出8株副溶血性弧菌,血清分型O2:K28构成比占25.00%(2/8);O8:K21构成比占75.00%(6/8);经PFGE分子分型,2株O2∶K28血清型(VP18171、VP18175)相似度为66.7%;3株O8∶K21血清型(VP18172、VP18173、VP18176)相似度为100.0%,与另外3株O8∶K21血清型(VP18177、VP18174、VP18170)相似度为88.4%~95.2%;药敏试验结果显示,除有1株菌株对氨苄西林、头孢唑林二重耐药、1株菌株对氨苄西林耐药、3株菌株对头孢唑林耐药外,其它菌株对所有测试药物均敏感,无多重耐药现象。结论 此次食物中毒是由O2:K28和O8:K21这两种罕见血清型的副溶血性弧菌混合感染引起的。     

RAW TROPICAL OYSTERS AS VEHICLES FOR MULTIDRUG-RESISTANT Vibrio parahaemolyticus

The following study aimed to determine the antimicrobial susceptibility profile of Vibrio parahaemolyticus strains from fresh and frozen oysters Crassostrea rhizophorae sold in Fortaleza-Brazil. An antibiogram was performed on 87 isolates using nine antibiotics: gentamicin (Gen 10 µg), ampicillin (Amp 10 µg), penicillin G (Pen 10U), ciprofloxacin (Cip 5 µg), chloramphenicol (Chl 30 µg), nalidixic acid (Nal 30 µg), tetracycline (Tet 30 µg), vancomycin (Van 30 µg) and erythromycin (Ery 15 µg). All strains were resistant to at least one antibiotic, and 85 (97.7%) were multi-resistant, with predominance of the Van+ Pen+Amp resistance profile (n = 46). Plasmid resistance to Pen, Amp and Ery was detected. Thus, the risk that raw oyster consumption poses to the health of consumers is highlighted, due to the fact that these bivalves may host antibacterial-resistant microorganisms.     

Characteristics of Vibrio cholerae O1 isolated from water of the River Ganga,Varanasi, India

Background: Vibrio cholerae is an autochthonous inhabitant of fresh and brackish water and estuarine system. Investigation of V. cholerae from the River Ganga seems important to find variation in CTX arrangement and genomic diversity. Objectives: To investigate V. cholerae O1 strains for the presence of virulence and regulatory genes, variation in number and organisation of the pre-CTXΦ and/or CTXΦ, and for the genomic diversity. Materials and Methods: Polymerase chain reaction (PCR) was used to detect virulence and regulatory genes, type of rstR and location of CTXΦ on the chromosome. Southern hybridisation was conducted to see the number and arrangement of pre-CTXΦ and CTXΦ. Ribotyping and pulsed-field gel electrophoresis were used to find genetic relatedness. Results: Seven strains gave positive results by PCR for the gene encoding for ctxA, zot, ace, tcpA (El Tor), ompU, and toxR, except one strain that was negative for the ctxA. Three strains were positive for the tcpA (El Tor), ompU and toxR genes. Determination of CTX organisation showed that among the ctx-positive strains, four harboured two copies of CTX^ETΦ arranged in tandem and two harboured one copy of CTX^ETΦ, and one ctx-negative strain harboured only one copy of pre-CTX^ETΦ. Pulsotype and ribotype analysis showed existence of at least three pulsotype and ribotypes indicating diversity in genomic content among them. Conclusion: This study thus indicates that multiple clones (ribotypes/pulsotypes) of V. cholerae O1 carrying pre-CTXΦ and/or CTXΦ and ctx-negative strains were present in the water of the River Ganga, Varanasi, India.     

A new emerging serotype of Vibrio parahaemolyticus in China is rapidly becoming the main epidemic strain

ObjectivesDuring surveillance, we found a new type of Vibrio parahaemolyticus named ‘O4:KUT-recAin’ and studied the phenotypic, pathogenic and epidemiological characteristics of O4:KUT-recAin.MethodsV. parahaemolyticus were isolated from acute diarrhoeal patients in coastal hospitals of China. Serum agglutination test, specific PCR assay, growth curves under different conditions and rabbit diarrhoeal models were using to characterize O4:KUT-recAin.ResultsThe O4:KUT-recAin strain has a new type of K antigen and a 25 043-bp-large fragment encoding 20 proteins inserted in the housekeeping gene recA. Retrospective analysis found that only one O4:KUT-recAin strain was detected in 563 V. parahaemolyticus strains in 2014; then the proportion increased rapidly and reached 17.8% (105/590) in 2016 and 31.1% (224/721) in 2017, making O4:KUT-recAin the second dominant serotype following O3:K6. O4:KUT-recAin strains (100%, 14/14) exhibited increased acid resistance and could reproduce in medium at pH 4.9, while 92.9% (13/14) of the O3:K6 strains could not grow at this pH value. O4:KUT-recAin could cause diarrhoea and small intestinal tissue lesions in infant rabbits, but its diarrhoeal (93.1%, 27/29) and mortality (78.6%, 22/28) rates were slightly lower than those of O3:K6 (100% 16/16, 100% 16/16). Based on diarrhoea patients, there were no significant differences in the two groups for most clinical symptoms and laboratory results, except media age, haemoglobin and the number of red blood cells in stool samples.ConclusionsO4:KUT-recAin had enhanced acid resistance, was capable of causing infectious diarrhoea in both rabbits and humans, and has become widespread during a short period of time in China.     

O139霍乱弧菌生物学特性及药物敏感性分析

为了有效、准确地检测霍乱弧菌，在某地水样泻患者的粪便中分离４株Ｏ１３９霍乱弧菌，经对分离株的生物学特性、血清学及药物敏感性进行研究，并与Ｏ１群霍乱弧菌进行比较。结果表明，Ｏ１３９霍乱弧菌具有Ｏ１群同样的生化特性，但不与Ｏ１群霍乱弧菌抗血清凝集，仅与Ｏ１３９霍乱弧菌抗血清在玻片上呈强凝集，试管凝集滴度为１：６４０～１：２５６０，所有菌株都使鸡红细胞凝集，对羊红细胞溶血的作用可变。所有菌株对霍乱Ｏ１群特异的ｍｕｋｈｅｒｊｅｅ＇ｓ噬菌体有抗性，对Ｏ／１２９多粘菌素Ｂ等药物耐药；而对红霉素、环丙氟哌酸等抗生素敏感。Ｏ１３９与Ｏ１群霍乱弧菌的不同特征，可作为鉴别的参考依据，但由于观察的菌株尚少，有待进一步研究。     

临床分离非O1/O139群霍乱弧菌毒力及耐药特征分析

目的 了解临床分离的非O1/O139群霍乱弧菌毒力及耐药特征。方法 收集2014-2015年北京友谊医院4-10月肠道门诊分离到的非O1/O139群霍乱弧菌,采用微量肉汤稀释法检测霍乱弧菌对15种抗生素的耐药性;PCR检测霍乱弧菌的毒力相关基因。结果 35株非O1/O139群霍乱弧菌对复方新诺明的耐药率(40.0%)最高,其次是氯霉素(28.5%)和磺胺异恶唑(22.6%),对阿莫西林/克拉维酸、头孢曲松、头孢西丁、头孢吡肟及亚胺培南完全敏感。毒力基因检测显示所有菌株均携带hlyA和ompU,hapA(97.1%)、rtxA(91.4%)、Ⅵ型分泌系统T6SS(94.3%~97.1%)、Ⅲ型分泌系统T3SS(80.0%~85.7%)和nanH(62.9%)阳性率较高;主要的毒力基因型为hlyA-rtxA-hapA-ompU-nanH-vasA-vasK-vasH-vcsC-vcsV-vcsN-vspD(40.0%)。结论 临床分离非O1/O139群霍乱弧菌毒力基因多样化,对抗菌药物耐药性较高,需加强腹泻病例中非O1/O139群霍乱弧菌的毒力及耐药监测。     

抗河流弧菌单克隆抗体的建立及初步鉴定

目的 制备高效、特异的抗河流弧菌单克隆抗体(monoclonal antibody,mAb),为海洋致病细菌的快速免疫诊断提供技术支持.方法 选用雌性BALB/c小鼠(8周龄)制备成为灭活河流弧菌免疫小鼠,利用杂交瘤细胞融合技术,制备出抗河流弧菌杂交瘤细胞株,用Giemsa染色对其进行染色体鉴定,并用酶联免疫吸附试验(enzyme linked immunosorbent assay,ELISA)方法筛选其与河流弧菌及其他重要海洋细菌的交叉反应特异性.结果 共获得4株抗河流弧菌mAb,均符合杂交瘤细胞染色体特点,具有良好的特异性和免疫反应性,分别命名为01H10,02F12,05F3和03G10.结论 本研究制备、筛选出抗河流弧菌的mAb,有助于建立抗河流弧菌快速免疫检测试剂盒.     

柳珊瑚共附生真菌Alternaria sp.(WZL003)抑菌化合物的分离及其作用机制初步研究D

目的研究1株柳珊瑚共附生真菌具有抑菌活性次级代谢产物及抑菌作用机制。方法采用活性追踪分离的方法,运用硅胶柱层析、Sephadex LH-20凝胶柱层析和半制备HPLC等手段,对采自中国南海的柳珊瑚Echinogorgia rebekka中分离获得的共附生链格孢霉属真菌Alternaria sp.(WZL003)的发酵产物进行分离和纯化,利用NMR、MS等波谱方法,并与文献对照,确定化合物的结构;以海洋病原菌和污损菌鳗弧菌Vibrio anguillarum为对象研究化合物的抑菌作用机制。结果从该菌发酵液的乙酸乙酯提取物中,分离获得1个对V.anguillarum具有较强抑菌活性的蒽醌类化合物macrosporin。结论初步的抑菌作用机制研究发现,该化合物能破坏鳗弧菌的细胞壁和细胞膜,导致细胞通透性增加,胞内大量内容物外泄,最终导致菌体死亡,从而起到抑菌作用。本研究首次报道了macrosporin对鳗弧菌的抑菌作用及其作用机制。     

2011—2013年北京某城区感染性腹泻患者致病菌检测分析

目的分析北京某城区2011—2013年感染性腹泻患者致病菌分布及脉冲场凝胶电泳(PFGE)图谱特征,为感染溯源提供依据。方法收集2011年1月—2013年12月该区域肠道门诊感染性腹泻患者粪便标本1 179份,对其培养分离的致病菌进行血清分型及PFGE分析。结果 1 179份标本,共培养肠道病原菌330株,其中检出居前4位的肠道致病菌依次为志贺菌属93株(28.18%)、沙门菌属69株(20.91%)、副溶血性弧菌44株(13.33%)及致泻性大肠埃希菌11株(3.33%)。18株宋内志贺菌PFGE分为8个型别,聚类相似度接近88%;69株沙门菌属细菌分为18个血清型,共41种PFGE型别,其中山夫登堡沙门菌和肠炎沙门菌具有明显的优势带型;23株副溶血性弧菌PFGE型别较为分散。结论 3年间感染性腹泻患者致病菌的血清型和PFGE带型分布较为广泛,应注意沙门菌属和志贺菌属细菌的PFGE优势菌型,警惕其引发的感染性腹泻暴发流行。