感控干预在控制多重耐药定植菌医院感染的临床研究

目的研究多重耐药定植菌与医院感染的关系以及去定植措施的效果。方法对入住ICU的患者进行多重耐药定植菌筛查,观察阳性患者和阴性患者医院感染发生率;将阳性患者随机分为对照组和试验组,对照组采用常规的预防控制措施,试验组加上安尔碘Ⅲ去鼻腔MRSA、口服金双歧去肠道产ESBLs肠杆菌措施,观察两组患者医院感染发生率以及定植菌与医院感染的关系,对比两组去定植效果。结果ICU多重耐药菌定植率为31. 16% ;多重耐药定植菌筛查阴性患者医院感染率为7. 56%,阳性患者医院感染率为15.47% （P 〈0.01）;对照组医院感染率为20.79%,试验组医院感染率为22. 22% （P 〉0. 05）;对照组定植菌医院感染率为4. 95% ,试验组定植菌医院感染为0（ P 〈0.01）;对照组产ESBLs大肠埃希菌定植自行清除率为26. 31% ,试验组产ESBLs大肠埃希菌去定植率为80. 95% （P 〈 0. 01）。结论ICU患者多重耐药菌定植率高,多重耐药菌定植患者医院感染率高,口服金双歧去肠道产ESBLs细菌干预措施有效,安尔碘Ⅲ去鼻腔MRSA效果需继续研究。     

Type-Specific Human Papillomavirus Biological Features: Validated Model-Based Estimates

Infection with high-risk (hr) human papillomavirus (HPV) is considered the necessary cause of cervical cancer. Vaccination against HPV16 and 18 types, which are responsible of about 75% of cervical cancer worldwide, is expected to have a major global impact on cervical cancer occurrence. Valid estimates of the parameters that regulate the natural history of hrHPV infections are crucial to draw reliable projections of the impact of vaccination. We devised a mathematical model to estimate the probability of infection transmission, the rate of clearance, and the patterns of immune response following the clearance of infection of 13 hrHPV types. To test the validity of our estimates, we fitted the same transmission model to two large independent datasets from Italy and Sweden and assessed finding consistency. The two populations, both unvaccinated, differed substantially by sexual behaviour, age distribution, and study setting (screening for cervical cancer or Chlamydia trachomatis infection). Estimated transmission probability of hrHPV types (80% for HPV16, 73%-82% for HPV18, and above 50% for most other types); clearance rates decreasing as a function of time since infection; and partial protection against re-infection with the same hrHPV type (approximately 20% for HPV16 and 50% for the other types) were similar in the two countries. The model could accurately predict the HPV16 prevalence observed in Italy among women who were not infected three years before. In conclusion, our models inform on biological parameters that cannot at the moment be measured directly from any empirical data but are essential to forecast the impact of HPV vaccination programmes.     

医院内感染422例的微生态学分析

本文对我院在１９９２年６月至１９９３年５月８５２０例出院病人中,参照卫生部医政司院内感染监控协调小组确定的标准分类的４２２例院内感染进行调查和微生态分析。院内感染总发生率为４．９５％,依次以肾移植血液透析中心、血液病科、监护中心较高,分别为５０．８８％、２６．２９％、２４．０７％,按年龄分组以大于５０岁组院内感染率最高,为４４．３９％。院内感染部位以下呼吸道感染最高（３９．６３％）,其次为手术伤口感染（２９．０７％）,泌尿道感染（１１．５８％）。院内感染病医学检查以“Ｇ￣－”杆菌为主（５１．５％）,真菌感染为３３．５３％。药敏试验对抗茵素都有不同程度耐药。提示要高度重视院内感染监测,严格控制抗生素应用,重视对手术室、病区环境净化和对病人的保护性措施,以预防和治疗院内感染。     

Theoretical and empirical derivation of cardiovascular allometric relationships in children.

Basic fluid dynamic principles were used to derive a theoretical model of optimum cardiovascular allometry, the relationship between somatic and cardiovascular growth. The validity of the predicted models was then tested against the size of 22 cardiovascular structures measured echocardiographically in 496 normal children aged 1 day to 20 yr, including valves, pulmonary arteries, aorta and aortic branches, pulmonary veins, and left ventricular volume. Body surface area (BSA) was found to be a more important determinant of the size of each of the cardiovascular structures than age, height, or weight alone. The observed vascular and valvar dimensions were in agreement with values predicted from the theoretical models. Vascular and valve diameters related linearly to the square root of BSA, whereas valve and vascular areas related to BSA. The relationship between left ventricular volume and body size fit a complex model predicted by the nonlinear decrease of heart rate with growth. Overall, the relationship between cardiac output and body size is the fundamental driving factor in cardiovascular allometry.     

Use of nasal mupirocin for Staphylococcus aureus: effect on nasal carriers and nosocomial infections

Staphylococcus aureus is the agent of community-acquired and nosocomial infections. Twenty to 35% of the population permanently carries it in the nose and oropharynx, and additional 50%, carries it intermittently. Topical calcium mupirocin is an antibacterial agent against Staphylococcus aureus recommended to eradicate nasal and hand colonization in patients and health care workers. The prevalence of nasal S. aureus was determined in patients undergoing cardiovascular surgery. In addition, the effect of mupirocine on the number of carriers and rate of nosocomial infections was evaluated. An experimental prospective study was undertaken with two groups of patients: one treated with mupirocin (n = 96), and the other without treatment (n = 95). Tests for presence of nasal S. aureus and nosocomial infections were conducted in all patients. A 34% prevalence of S. aureus carriers was found. A decrease of the prevalence was found in both treated (87%) and untreated patients (33%), but in significantly different proportions (p = 0.0002, RR = 0.22, 95%CI = 0.09-0.054). This result demonstrated the effectiveness of a mupirocin treatment program to decrease numbers of nasal carriers. With regard to nosocomial infection, S. aureus prevalence was 3.6%, occurring mostly in control patients (6 of 7). Total nosocomial infection prevalence was 17.3%, evenly distributed in treated and untreated patients. This suggested that mupirocin use did not decrease the number of nosocomial infections.     

Mathematische Simulation des Elektroretinogramms isolierter Netzhäute glaukomerkrankter Augen

Summary The electroretinogram of isolated retinae of human eyes which had to be enucleated owing to an absolute glaucoma was split into two components: a negative one identified as P III and an oscillating one. By means of electronic computations two corresponding mathematical functions were fit successively to the experimental curve and then added for comparison. Though this synthetisized curve differs markedly from the empirical one in the later part, it shows a close fit in the initial state. Limitations of the mathematical simulation model are discussed.     

院内患者深部真菌感染的流行病学调查

目的 了解长海医院院内患者深部真菌感染的流行病学情况。方法 对2000-2004年间在长海医院住院治疗患者的深部真菌感染进行调查和分析。结果 5年间院内深部真菌感染的发病率上升明显,院内深部真菌感染的主要部位是呼吸道和泌尿道,主要的致病菌为念珠菌。结论 院内深部真菌感染病例近年呈上升趋势。白念珠菌仍是院内深部真菌感染的主要病原菌。     

胃息肉与幽门螺杆菌感染关系研究

目的探讨胃息肉与幽门螺杆菌（Helicobacter pylori,H.pylori）感染关系。方法对1218例胃息肉同时进行H．pylori检查患者进行回顾性分析,分析胃息肉患者H.pylori感染率、胃息肉部位与H.pylori感染关系、胃息肉病理类型与H.pylori感染关系。结果发现胃息肉Hpylori感染患者532例,Hpylori感染率为43．7％。男性胃息肉患者H.pylori感染率为47．5％（216／455）,女性Hpriori感染率感染率为41．4％（316／763）（P〉0．05）,年龄〈20岁、20～39岁、40—59岁和≥60岁胃息肉H.priori感染率分别为41．7％、44．7％、41．6％和47．2％（P〉0．05）;胃窦胃角息肉H.pylori感染率高于其他部位（胃体、胃底和贲门）（P〈0．05）;炎性和增生性胃息肉H.priori感染率高于胃底腺和腺瘤性息肉（P〈0．05）。结论H.pylori感染可能与部分胃息肉发生有一定关系,需要进一步深入研究胃息肉的发生机制。     

Estimation of yield in wheat from measurements of photosynthesis and translocation in the field

The rate of photosynthesis of ears, flag leaves and second leaves of two varieties of wheat, and the proportion of synthesized carbohydrate translocated from them to the grain, were determined in the field using ¹⁴CO₂. The relationship of rate of photosynthesis to changes in age and in incident radiation was expressed by parameters determining hyperbolic functions. These were combined with empirical equations describing the increase with age in the proportion of photosynthate stored in the grain, to form a mathematical model by which yield was determined from physiological parameters. This model gave estimates of yield in reasonable agreement with measured values.     

急性脑梗死患者医院感染临床特点与影响因素分析

目的:探讨急性脑梗死患者医院感染临床特点及影响因素。方法:回顾性分析我院2018年1月至2019年12月诊断为急性脑梗死1175例患者临床资料,通过感染标本的培养及鉴定结果分析,探讨医院感染的病原菌种类及比例,进一步分析引起医院感染的危险因素。结果:1175例急性脑梗死患者中,发生医院感染99例,感染率8.4%;最常见感染部位为呼吸系统和泌尿系统;发生医院感染的99例临床标本微生物学培养及鉴定发现革兰氏阴性菌59例,革兰氏阳性菌37例,真菌3例,分别占比59.60%、37.37%及3.03%;发生医院感染的独立影响因素包括:年龄≥80岁、反复发作史、住院期间行气管插管、血清白蛋白<30 g/L、25-羟维生素D3<20 ng/mL,既往有慢性阻塞性肺病、NIHSS≥6。结论:急性脑梗死患者医院感染发生以呼吸道及泌尿道感染最常见,诸多因素可以引起医院感染发生,重视侵入性操作的管理外,对于营养不良等也要引起重视,从而降低医院感染率。     

Biokinetic models for representing the complete inhibition of microbial activity at high substrate concentrations.

This paper reintroduces the Wayman and Tseng model for representing substrate inhibition effects on specific growth rate by further documenting its potential predictive capabilities. It also introduces a modification to this model in which an Andrews inhibition function is used in place of the Monod noninhibitory substrate function. This modification better represents the relationship between specific growth rate and substrate concentration for those substrates that show Andrews type inhibition at lower substrate concentrations, rather than the Monod type noninhibitory behavior described in the model of Wayman and Tseng. Results from nonlinear, least squares regression analysis are used to evaluate the ability of these models to empirically represent experimental data (both new and from the literature). The statistical goodness of fit is evaluated by comparing the regression results against those obtained using other empirical models. Finally, possible mechanisms of toxicity responsible for the observed inhibition trends are used to further justify use of these empirical models. The dominant mechanism considered to be relevant for conceptually explaining complete inhibition at high concentrations of solvents is the deterioration of cell membrane integrity. Literature citations are used to support this argument. This work should lead to improvements in the mathematical modeling of contaminant fate and transport in the environment and in the simulation of microbial growth and organic compound biodegradation in engineered systems.     

A quantitative test of the relationship between parasite dose and infection probability across different host-parasite combinations

Epidemiological models generally assume that the number of susceptible individuals that become infected within a unit of time depends on the density of the hosts and the concentration of parasites (i.e. mass-action principle). However, empirical studies have found significant deviations from this assumption due to biotic and abiotic factors, such as seasonality, the spatial structure of the host population and host heterogeneity with respect to immunity and susceptibility. In this paper, we examine the effect of the dose level of the bacterial endoparasite Pasteuria ramosa on the infection rate of its host, the water flea Daphnia magna. Using seven host clones and two parasite isolates, we measure the fraction of infected hosts after exposure to eight different parasite doses to determine whether there is variation in the infection process across different host clone-parasite isolate combinations. In five combinations, a pronounced dose-dependent infection pattern was found. Using a likelihood approach, we compare the infection data of these five combinations to the fit of three mathematical models: a mass-action model, a parasite antagonism model (i.e. an increase in the parasite dose leads to an under-proportionate increase in the infection rate per host) and a heterogeneous host model. We found that the host heterogeneity model, in which we assumed the existence of non-inherited phenotypic differences in host susceptibilities to the parasite, provides the best fit. Our analysis suggests that among 5 out of the 14 host clone-parasite isolate combinations that resulted in appreciable infections, non-genetic host heterogeneity plays an important role.     

Regulatory and activated T cells in human Schistosoma haematobium infections

Acquired immunity against helminths is characterised by a complex interplay between the effector Th1 and Th2 immune responses and it slowly manifests with age as a result of cumulative exposure to parasite antigens. Data from experimental models suggest that immunity is also influenced by regulatory T cells (Treg), but as yet studies on Treg in human schistosome infections are limited. This study investigated the relationship between schistosome infection intensity and the two cell populations regulatory T cells (TREG: CD4(+(dim))CD25(+(high))FOXP3(+)CD127(low)), and activated (Tact: CD4(+)CD25(+)FOXP3(-)) T cells in Zimbabweans exposed to Schistosoma haematobium parasites. Participants were partitioned into two age groups, young children (8-13 years) in whom schistosome infection levels were rising to peak and older people (14+ years) with declining infection levels. The relationship between Tact proportions and schistosome infection intensity remained unchanged with age. However Treg proportions rose significantly with increasing infection in the younger age group. In contrast Treg were negatively correlated to infection intensity in the older age group. The relative proportions of regulatory T cells differ significantly between young individuals in whom high infection is associated with an enhanced regulatory phenotype and older infected patients in whom the regulatory response is attenuated. This may influence or reflect different stages of the development of protective schistosome acquired immunity and immunopathogenesis.     

Population dynamics of Trichostrongylus colubriformis in sheep: mathematical model of worm fecundity

A mathematical model was constructed to predict the egg production of Trichostrongylus colubriformis worms as a function of worm age and host experience of infection. The model set egg production at zero until the worm was 14 days old, when a linear increase to maximum egg production levels occurred over 7 days. It was assumed that egg production remained at maximum levels until a threshold total worm burden was exceeded, when an exponential decline in egg production occurred. The rate of decline was assumed independent of worm age or worm burden. The estimated parameters (maximum egg production, threshold, lag and rate of decline) were optimized by fitting values predicted from the model to faecal egg counts observed in continuously infected sheep, giving R2 = 0.80. The model was validated against faecal egg counts obtained in two other continuous infection experiments, one performed at the same laboratory and the other in Britain.     

Hospital-acquired infection: present and future impact and need for positive action

Surveillance of infections at the Ottawa General Hospital between September 1, 1971 and August 31, 1972 showed that the overall infection rate was 13.5% of which 5.6% was community-acquired while 7.9% was of nosocomial origin. These figures are comparable to those for equivalent hospitals in the United States and lower than those reported from the Boston City Hospital, but they nevertheless indicate that over half the infected patients in the hospital were infected after admission. Urinary tract infections accounted for 44.8% of all nosocomial infections and clearly dominated the picture. The postoperative wound infection rate was 3.9% and accounted for only 18% of nosocomial infections. It is probable that these findings are representative of general hospitals throughout Canada and indicate conditions which will not long be tolerated. The knowledge and techniques exist for the prevention of all hospital cross-infection and much autogenous infection. Specific measures are suggested for working towards this goal. These are (1) the replacement of archaic hospitals and hospital facilities, (2) the establishment in every hospital of an efficient surveillance program, (3) the institution of good catheterization and catheter care techniques, and (4) the establishment by hospitals of a quality control program whereby a specific explanation is required for every infection occurring within the hospital.     

Experimental and clinical study of immunomodulators Immunomax and Gepon in complex treatment of acute purulent surgical infection]

The efficacy of the immunomodulators immunomax and gepon in the treatment of acute purulent surgical infection of soft tissues was studied under experimental and clinical conditions. Gepon was used in the form of 0.04% ointment in the phase of the wound infection regeneration vs. the routine use of 10% methyluracil ointment. Immunomax was administered in a dose of 40 units under the experimental conditions and 200 units in the clinical trial 3 times every 2nd day intramuscularly. The experimental investigation was performed on 20 male guinea pigs in a model of a suppurating wound. The animals were divided into 2 groups (main and control) of 10 animals each. Flat wounds were prepared according to the A. V. Nikolaev's method. The clinical trial enrolled 126 patients with acute surgical infection of the soft tissues. The patients were treated in the Hospital of General Surgery of the Faculty of Pediatrics of the Russian State Medical University during the period from 2003 to 2004. The patients were divided into 2 groups (main and control). The structure of the main and control groups was comparable by the sex and age of the patients, nosological forms and severity of the disease. The patients of the main group (65 subjects) were given the immunomodulators in complex with the routine surgical treatment and drug therapy. The patients of the control group (61 subjects) were given the same surgical treatment and drug therapy but without the use of the immunomodulators. General and local manifestations of the purulent infection were considered as the criteria of the treatment efficacy. The qualitative and quantitative composition of the wound bacterial infection was determined and histological examination of the wound bioptates was performed. Planimetry of the wound surface was carried out and the acceleration index of the wound clearing and healing was evaluated. In the total, high therapeutic efficacy of immunomax and gepon, practically no contraindications and adverse reactions to their use, the ease and simplicity of their handling can be stated.     

The Role of Social Contacts and Original Antigenic Sin in Shaping the Age Pattern of Immunity to Seasonal Influenza

Recent serological studies of seasonal influenza A in humans suggest a striking characteristic profile of immunity against age, which holds across different countries and against different subtypes of influenza. For both H1N1 and H3N2, the proportion of the population seropositive to recently circulated strains peaks in school-age children, reaches a minimum between ages 35–65, then rises again in the older ages. This pattern is little understood. Variable mixing between different age classes can have a profound effect on disease dynamics, and is hence the obvious candidate explanation for the profile, but using a mathematical model of multiple influenza strains, we see that age dependent transmission based on mixing data from social contact surveys cannot on its own explain the observed pattern. Instead, the number of seropositive individuals in a population may be a consequence of ‘original antigenic sin’; if the first infection of a lifetime dominates subsequent immune responses, we demonstrate that it is possible to reproduce the observed relationship between age and seroprevalence. We propose a candidate mechanism for this relationship, by which original antigenic sin, along with antigenic drift and vaccination, results in the age profile of immunity seen in empirical studies.     

On the kinetics of anaerobic power

ABSTRACT: BACKGROUND: This study investigated two different mathematical models for the kinetics of anaerobic power. Model 1 assumes that the work power is linear with the work rate, while model 2 assumes a linear relationship between the alactic anaerobic power and the rate of change of the aerobic power. In order to test these models, a cross country skier ran with poles on a treadmill at different exercise intensities. The aerobic power, based on the measured oxygen uptake, was used as input to the models, whereas the simulated blood lactate concentration was compared with experimental results. Thereafter, the metabolic rate from phosphocreatine break down was calculated theoretically. Finally, the models were used to compare phosphocreatine break down during continuous and interval exercises. RESULTS: Good similarity was found between experimental and simulated blood lactate concentration during steady state exercise intensities. The measured blood lactate concentrations were lower than simulated for intensities above the lactate threshold, but higher than simulated during recovery after high intensity exercise when the simulated lactate concentration was averaged over the whole lactate space. This fit was improved when the simulated lactate concentration was separated into two compartments; muscles + internal organs and blood. Model 2 gave a better behavior of alactic energy than Model 1 when compared against invasive measurements presented in the literature. During continuous exercise, model 2 showed that the alactic energy storage decreased with time, whereas model 1 showed a minimum value when steady state aerobic conditions were achieved. During interval exercise the two models showed similar patterns of alactic energy. CONCLUSIONS: The current study provides useful insight on the kinetics of anaerobic power. Overall, our data indicates that blood lactate levels can be accurately modeled during steady state, and suggests a linear relationship between the alactic anaerobic power and the rate of change of the aerobic power.     

Nosocomial infections and risk factors in intensive care units

The present study was performed to describe the incidence and risk factors for nosocomial infections (NIs) in the intensive care units of a University hospital. From January to July 2002, 454 patients from Medical and Surgical Intensive Care Unit (MICU and SICU) were observed in the active, targeted, prospective surveillance study. Risk factors for NIs were found by logistic regression analysis. Two hundred and eighteen NIs were recorded in 149 of 454 screened patients. The overall incidence rate was calculated as 33% in the ICUs. The incidence was 39% in MICU and 29% in SICU. The most frequent nosocomial infection observed in MICU, and SICU was pneumonia (42%), and surgical wound infection (31%), respectively. Extrinsic risk factors were urinary catheter, mechanical ventilation, total parenteral nutrition, entubation, antimicrobial treatment prior to the NI, nasogastric cathater and central catheter. The highest intrinsic risk factor was unconsciousness in MICU, respiratory failure in SICU. This high NI rates may be reduced by timely feedback of data for infection control activities. The recognition of risk factors for NIs is an important tool for the identification and development of interventions to minimize such risks in the ICU's.