Organization and nucleotide sequence of the Streptococcus mutans galactose operon

The galactose operon encoding a repressor and genes for the Leloir pathway for galactose metabolism (galactokinase, galactose-1-phosphate-uridyl transferase and UDP glucose-4-epimerase) was located adjacent to the multiple sugar metabolism (msm) operon on the chromosome of Streptococcus mutans Ingbritt (serotype c) and the complete nucleotide sequence of this 5-kilobase region was determined. The Leloir pathway was induced by the presence of galactose in the growth medium or following the release of intracellular galactose after uptake and cleavage of -galactosides by the multiple sugar metabolism system. Analysis of the mechanism of galactose transport confirmed the absence of a galactose-specific phosphotransferase system and suggested the presence of an inducible galactose permease. Evidence is presented that galactose transport is independent of the proton motive force and may be ATP-dependent.     

正常菌群对常见致病菌拮抗作用的研究

生物拮抗作用是微生物种群关系研究的一个侧面,实验中我们使用从皮肤上分离的常住菌——痤疮丙酸杆菌(A14-1)和表皮葡萄球菌(F65)对常见致病菌如金黄色葡萄球菌(C189)、绿脓杆菌(C8514)和埃希氏大肠杆菌(C1356)的体外拮抗试验表明,它们具有明显的拮抗作用,拮抗作用一般从48小时开始,72小时明显。而皮肤常住菌间无拮抗作用,相反它们还有协同作用,这对于皮肤的自净以及维持皮肤的微生态平衡具有重要的作用。此外,实验中还进行了乳杆菌和双歧杆菌等正常菌群分离株与上述常见致病菌的体外拮抗试验,结果表明也     

重症肺炎患者病原菌分布、临床结局分析及血清尿素氮与肌酐比值、尿素氮与白蛋白比值联合检测的临床意义

摘要 目的：分析重症肺炎（SP）患者病原菌分布和临床结局并探讨血清尿素氮与肌酐比值（UCR）、尿素氮与白蛋白比值（UAR）联合检测的临床意义。方法：选取2019年8月～2022年8月三六三医院收治的107例SP患者,根据临床结局分为死亡组和存活组。分析SP患者病原菌分布情况。采用单因素和多因素Logistic回归分析SP患者临床结局的影响因素,采用受试者工作特征（ROC）曲线分析血清UCR、UAR水平对SP患者临床结局的评估价值。结果：107例SP患者痰液标本中培养出122株病原菌,其中革兰阴性菌75株（61.48%）,革兰阳性菌39株（31.97%）,真菌8株（6.56%）。107例SP患者院内死亡率为40.19%（43/107）。多因素Logistic回归分析显示,年龄增加、肺外并发症≥2个和UCR、UAR升高为SP患者临床结局不良的独立危险因素,氧合指数增加为其独立保护因素（P＜0.05）。ROC曲线分析显示,血清UCR、UAR联合评估SP患者临床结局的曲线下面积（AUC）大于各指标单独评估。结论：SP患者病原菌分布以革兰阴性菌为主,血清UCR、UAR升高为SP患者临床结局不良的独立危险因素,可能成为SP患者临床结局的辅助评估指标,且二者联合评估SP患者临床结局的价值较高。     

ICU呼吸机相关性肺炎患者病原菌分布及NLR、血清磷、PCT联合检测对死亡风险的预测价值探讨

摘要 目的：研究重症监护室（ICU）呼吸机相关性肺炎（VAP）患者病原菌分布及中性粒细胞与淋巴细胞计数比值（NLR）、血清磷、降钙素原（PCT）联合检测对死亡风险的预测价值。方法：选取上海市第一人民医院于2020年1月～2022年1月收治的60例VAP患者。采集所有患者呼吸道分泌物并进行细菌培养。此外,将其按照预后的不同分为死亡组21例以及存活组39例,比较两组NLR、血清磷及PCT水平。以单因素及多因素Logistic分析VAP患者死亡的危险因素,并通过受试者工作特征（ROC）曲线分析NLR、血清磷及PCT预测死亡的效能。结果：60例VAP患者呼吸道分泌物检出病原菌共82株,以革兰阴性菌占比最高,共检出革兰阴性菌75.61%、革兰阳性菌21.95%、真菌2.44%。按照占比从高到低的顺序分别为鲍氏不动杆菌20.73%,铜绿假单胞菌18.29%,肺炎克雷伯菌17.07%,金黄色葡萄球菌13.41%,大肠埃希菌12.20%,其他革兰阴性菌7.32%,表皮葡萄球菌4.88%,肠球菌属3.66%,真菌2.44%。死亡组NLR及PCT水平均高于存活组,而血清磷水平低于存活组（P＜0.05）。单因素分析结果显示：急性生理与慢性健康评分（APACHEⅡ）评分及有创机械通气时间均和VAP患者死亡有关（P＜0.05）。多因素Logistic回归分析显示：APACHEⅡ评分较高、有创机械通气时间较长与NLR、PCT水平较高均是VAP患者死亡危险因素,血清磷水平较高是VAP患者死亡的保护因素（P＜0.05）。ROC曲线分析显示：NLR、血清磷及PCT联合预测VAP患者死亡的效能优于上述三项指标单独预测。结论：VAP患者主要病原菌为革兰阴性菌,临床应合理选用抗菌药物治疗,NLR、血清磷及PCT均和患者死亡有关,联合检测对死亡风险的预测价值较高。     

重症急性胰腺炎合并腹腔感染患者病原菌分布、药物敏感性分析及其院内死亡的危险因素探讨

摘要 目的：观察重症急性胰腺炎（SAP）合并腹腔感染（IAI）患者病原菌分布,分析药物敏感性,同时探讨其院内死亡的危险因素。方法：本研究纳入2017年1月~2022年1月期间来解放军联勤保障部队第九二二医院接受治疗并确诊的SAP合并IAI患者100例,采集患者腹水标本,观察其病原菌分布,分析药物敏感性。入院后收集患者人口学特征、实验室检查等资料,探讨患者院内死亡的危险因素。结果：100例SAP合并IAI患者腹水标本中,分离出186株病原菌,其中革兰阴性菌有108株,占比58.06%。革兰阳性菌51株,占比27.42%。真菌27株,占比14.52%。鲍曼不动杆菌对不同抗菌药物的敏感性均较低,大肠埃希菌对厄他培南、亚胺培南、哌拉西林／他唑巴坦、庆大霉素、美罗培南的敏感性较高,肺炎克雷伯菌对亚胺培南、美罗培南的敏感性较高,葡萄球菌属对替加环素、万古霉素、利奈唑胺的敏感性较高,屎肠球菌对替加环素、利奈唑胺的敏感性较高,粪肠球菌对氨苄西林、万古霉素、环丙沙星、替加环素的敏感性较高。单因素分析显示,SAP合并IAI患者院内死亡与器官障碍数目、膀胱压、入院时急性生理学与慢性健康状况评分（APACHE II）评分、白细胞计数（WBC）、血钙、红细胞压积（HCT）、总胆固醇（TC）、甘油三醋（TG）、降钙素原（PCT）、C反应蛋白（CRP）、动脉二氧化碳分压（PaCO₂）、动脉氧分压（PaO2）有关（P<0.05）。多因素Logistic回归分析结果显示：器官障碍数目偏多、血钙偏低、CRP偏高、APACHE II评分偏高、膀胱压偏高、PaO₂偏低、WBC偏高是导致SAP合并IAI患者院内死亡的危险因素（P<0.05）。结论：SAP合并IAI患者病原菌分布以革兰阴性菌为主,主要的革兰阴性菌、革兰阳性菌耐药率高。此外,器官障碍数目偏多、血钙偏低、CRP偏高、APACHE II评分偏高、膀胱压偏高、PaO₂偏低、WBC偏高是影响SAP合并IAI患者院内死亡的危险因素。     

A study of pathogenic factors of Streptococcus pneumoniae strains causing meningitis

Abstract Pneumococcal meningitis in St. Petersburg in the period 1985–1991 occurred in 1.7–2.3 children per 100 000 annually. The most common serotypes among pneumococcal strains isolated from patients with meningitis were 19, 1, 6, 15, and 2, whereas, among the capsulated strains isolated from carriers, type 3 predominated. Only one third of strains from cases of meningitis were highly virulent for mice (types 1, 2, 3). Hyaluronidase was produced by all the 39 studied strains, 22 (84.6±7.1%) out of 26 strains from patients with otitis media, and only by 15 (11.5±2.8%) out of 130 strains isolated from carriers. Non-capsulated strains lacked this enzyme. Results of intranasal inoculation of pneumococcal strains with different hyaluronidase activity and addition of exogenous hyaluronidase to strains which did not produce the enzyme confirm the hypothesis that this enzyme plays an important role in bacterial dissemination and breaching of the blood brain barrier by pneumococci. It was concluded that high hyaluronidase activity, presence of capsule, and pneumolysin or serotype (1, 2, and 19) despite hyaluronidase titer, are the most important factors contributing to the development of pneumococcal meningitis. The role of the mouse toxic factor is unclear.     

致病性暗色霉的浆膜超微结构分类学意义初探

对致病性暗色霉中的着色霉(Fonsecaea Negroni)外瓶霉(Exophiala Charmichael)瓶霉(Phialophoro Medlar)中的五种真菌浆膜超微结构进行了冰冻蚀刻研究,发现裴氏着色霉(Fonsecaea pedrosoi)和紧密着色霉(F.compacta)的内折长而宽,较深,略有弯曲,数量少,多呈平行或垂直排列。皮炎外瓶霉(Exophiala dermatitidis)的内折数量多,密集而分布均匀,呈圆点状或圆棒状。棘状外瓶霉(Exophiala spinifera)的内折少而表浅,多为圆形。疣状瓶霉(Phialophora verrucosa)的内折数量,排列,形状无一定规律。据上述特征,着色霉可以与外瓶霉,疣状瓶霉区别开来,皮炎外瓶霉也可与棘状外瓶霉区分。浆膜超微结构的性状有一定的分类学意义。     

Age dependent alterations in phospholipid composition of a saprophytic and a pathogenic strain of Nocardia

Nocardia polychromogenes (saprophytic) and Nocardia asteroides (pathogenic) showed characteristic patterns in changes of cellular lipids during growth. Total lipids and total phospholipids decreased with the age of the culture in the saprophytic strain, whereas in the pathogenic strain total lipids increased throughout the culture period and the total phospholipids decreased in the late stationary phase. The decrease in total phospholipids in saprophytic strain was reflected in the individual phosphatides. In the pathogenic strain, the phosphatidylinositomannoside content doubled in early stationary phase. Differences were observed in fatty acid composition of phosphatides at various stages of growth, but the ratio of saturated to unsaturated fatty acids remained unaltered.     

NleB/SseKs ortholog effectors as a general bacterial monoglycosyltransferase for eukaryotic proteins

Protein glycosylation is the most common post-translational modification as more than 50% of all human proteins are glycosylated. Pathogenic bacteria glycosylation allows adhesion to host cells and manipulates eukaryotic functions. A variety of acceptor proteins in bacterial glycosylation was recently discovered. Especially NleB/SseKs type III effectors unexpectedly glycosylate a poor nucleophile arginine. Other pathogenic toxins modify the unusual tyrosine, as well as canonical serine/threonine residues. And a huge diversity is found in target proteins; Rho/Ras families, death domains and moreover themselves for autoglycosylation. However, in spite of this acceptor diversity, all their sugar donors are only UDP-Glc/-GlcNAc and structural alignments as liganded show their catalytic cores are geometrically conserved, where DRY and DXD motives and W residues equally position to hold the sugar donors and to π-π bind with a uridine ring, respectively. Therefore, bacterial glycosyltransferases have a key for carbohydrate research problems concerning the sugar donors and target proteins recognition.