Tunnelled central venous catheters yield a low incidence of septicaemia in interleukin-2-treated patients

 A retrospective study on the incidence of catheter-related complications and catheter indwelling time (t _CI) during treatment with continuous interleukin-2 (IL-2) infusion in patients with metastatic renal cell cancer, who were equipped with tunnelled central venous catheters (CVC). A group of 72 patients were treated with IL-2-based immunotherapy. Two induction treatment cycles of 35 days each were used. Treatment consisted of IL-2 as a continuous intravenous infusion (c.i.v.) with lymphokine-activated killer cells and interferon α intramuscularly. A tunnelled CVC was inserted at the start of treatment and was kept in place for the duration of the therapy or until the occurrence of complications. Out of 72 CVC, 30 (42%) functioned uneventfully for a median t _CI of 64 days. In another 12 clinically uncomplicated cases (16%), catheter tips were positive in routine culture after a median t _CI of 33 days. In 18 patients (25%), CVC-related infections were noted, including 8 (11%) local tunnel infections and 10 (14%) septic episodes. These complications occurred at a median t _CI of 28 and 20 days respectively. In 15 (83%) of these 18 catheter infections, Staphylococcus aureus was isolated, whereas in the remaining 3 (17%) Staphylococcus epidermidis was found. Subclavian vein thrombosis was noted in 12 (17%) CVC at a median t _CI of 31 days; 5 (36%) of these were diagnosed in the first 14 patients. This prompted us to administer prophylactic heparin 15 000 IU c.i.v. daily during IL-2 treatment. Thereafter the incidence of thrombosis dropped to 7 (12%) in the subsequent 58 CVC inserted (P = 0.03). In conclusion, in contrast to previous reports on the high incidence of CVC-related septicaemia and thrombosis, we observed a relatively low incidence of these complications, which we ascribe to the use of tunnelled catheters and prophylactic heparin. Received: 9. January 1997 / Accepted: 13. March 1997     

Meningitis,pathogenicity near criticality: the epidemiology of meningococcal disease as a model for accidental pathogens

We formulate and analyse a model for infectious diseases transmitted by asymptomatic carriers finding, that if harmless and pathogenic strains of the infected agent compete, frequent outbreaks of the pathogenic strains can occur. A counterintuitively high number of clustered outbreaks at low pathogenicity in our model compares well with observations in diseases with severe and often fatal results for the host, as for example in meningitis. These clustered outbreaks can be described by the typical scaling behaviour around criticality. The epidemic model is a susceptible-infected-recovered system (SIR) for the harmless infective agent, acting as a background to a mutant strain Y which occasionally creates severely affected hosts X. The full system of SIRYX is described in the master equation framework, confirming limiting assumptions about a reduced YX-system with the SIR-system in stationarity. In this limiting case we can analytically show convergence to power law scaling typical for critical states, as well as the divergence of the variance of outbreaks near criticality. These large fluctuations of outbreaks of accidental pathogens as mutants of otherwise harmless commensal organisms is the challenging new feature of our model for future epidemiology of diseases like meningococcal disease.     

Rapid and quantitative detection of blood Serratia marcescens by a real-time PCR assay: its clinical application and evaluation in a mouse infection model

Large-scale nosocomial outbreaks of Serratia marcescens septicaemia in Japan have had a fatality rate of 20-60% within 48 h. As a countermeasure, a real-time PCR assay was constructed for the rapid diagnosis of S. marcescens septicaemia. This assay indeed detected S. marcescens in clinical blood specimens (at ca. 10(2)CFU ml(-1)), at a frequency of 0.5% in suspected cases of septicaemia. In mice, the assay provided estimates of blood S. marcescens levels at various infectious stages: namely, 10(7) to 10(8)CFU ml(-1) at a fatal stage (resulting in 100% death), 10(4)-10(5)CFU ml(-1) at a moderately fatal stage (resulting in 50% or more death), and <10(3)CFU ml(-1) at a mild stage (resulting in 100% survival), consistent with actual CFU measurements. Blood bacterial levels could be an important clinical marker that reflects the severity of septicaemia. The simultaneous detection of S. marcescens and the carbapenem resistance gene was also demonstrated.     

蝮蛇毒蛋白C激活物对败血症大鼠血小板聚集性的影响

目的观察蝮蛇毒蛋白C激活物(PCA)对败血症大鼠血小板聚集性的影响。方法将健康雄性SD大鼠30只,随机分为3组,即正常对照(NC)组,内毒素(LPS)模型组和PCA预处理组,每组10只。采用大剂量腹腔注射LPS复制大鼠败血症模型,观察和对比各组大鼠的临床表现、血小板聚集性和凝血酶原时间(PT)。结果与NC组相比较LPS模型组可使血小板聚集性显著下降(P<0.01),PT明显延长(P<0.01);PCA预处理组与LPS模型组相比较血小板聚集性明显升高(P<0.01),PT较LPS模型组明显缩短(P<0.01),而与NC组比较统计学差异无显著性,同时PCA预处理组可使大鼠临床症状较LPS模型组明显减轻。结论蝮蛇毒蛋白C激活物(PCA)可明显改善败血症大鼠的血液低凝状态。     

欧洲鳗鲡红头病病原的研究

我国南方各省欧洲鳗鲡养殖过程中,在黑仔及幼鳗期易发生一种以头部充血发红为主要特征的严重疾病,被称为“红头病”。本文描述了欧鳗红头病的症状,从病鳗血液中分离到３株菌,肌注和口服人工感染试验出现与自然发病相似的症状,死亡率分别９ ８３％和６７％,从病鳗身上重新分离到性状的菌株。４株分离菌的特性完全一致。均为革兰氏阴性杆菌,以周鞭毛运动,兼性压氧,发酵葡萄糖产酸,氧化酶阴性,过氧化氢酶阳性,还原硝酸盐Ｖ