Surgical Site Infections in Trauma and Orthopaedics at Bouaké Teaching Hospital (Côte d’Ivoire)

Background: Surgical site infections are serious healthcare problems. The aim was to describe the epidemiological, diagnostic, therapeutic, and prognostic aspects of surgical site infections in Trauma and Orthopaedics at Bouaké Teaching Hospital. Method: This retrospective, descriptive, and analytical study was conducted from January 2019 to December 31, 2021. The data studied included prevalence, initial lesions, type of surgical intervention, type of SSI, bacteria involved, treatment, and outcomes. Results: Forty-four (11%) of the 399 patients included in the study developed a surgical site infection. The mean age was 27 years, with 36 male and 8 female. Initial lesions were predominantly open fractures (n = 31;70%), with a mean delay of 48 hours for surgical management. Emergency interventions accounted for 70% (n = 31) of cases. The NNISS infection risk score was 1 in 80% (n = 35) of cases. Superficial infections (n = 34;77%) appeared early, on a mean 6 days postoperatively. Bacteriological analysis primarily identified Pseudomonas aeruginosa (n = 10;23%), sensitive to Imipenem and Chloramphenicol but resistant to Amoxicillin-clavulanic acid, Ceftriaxone, Gentamicin, and Ciprofloxacin. Multidrug-resistant bacteria were found in 89% (n = 8) of cases, with all bacteria resistant to Ceftriaxone. Surgical revision was performed in 10 patients (23%), primarily involving debridement with hardware retention (n = 7;70%). Chloramphenicol was the most commonly used antibiotic post-antibiogram (61%). Outcomes were favourable in 98% of cases. Identified risk factors included the type of lesion according to NRC classification, the delay in managing open fractures, and the NNISS score. Conclusion: The prevalence of surgical site infection was 11%, favoured by the delayed operation of open fractures.

Analysis of Clinical Characteristics and Risk Factors of Pseudomonas aeruginosa Bloodstream Infection in 55 Cases

Objective: Pseudomonas aeruginosa bloodstream infection presents a severe challenge to hospitalized patients. To investigate the clinical characteristics, risk factors and drug resistance of Pseudomonas aeruginosa bloodstream infection. Methods: Clinical data and laboratory results of patients with Pseudomonas aeruginosa bloodstream infection in the First Affiliated Hospital of Yangtze University from January 2019 to December 2022 were retrospectively analyzed. The factors associated with infection and death were analyzed by univariate analysis. Results: A total of 55 patients were enrolled in this study, The 28-day mortality rate was 14.5%. Univariate analysis showed that high procalcitonin, low albumin, ICU admission, central venous catheterization, indwelling catheter, and mechanical ventilation were associated with death. Multivariate Logistic regression analysis showed that hypoproteinemia and central venous catheters were independent risk factors for death in patients with Pseudomonas aeruginosa bloodstream infection. Conclusions: The drug resistance of P. aeruginosa bloodstream infection is not high, but the fatality rate is high. The combination of hypoalbuminemia after the onset of the disease and the use of central vein catheters can lead to increased mortality, suggesting that clinical identification of high-risk patients as early as possible, reducing the use of catheters, preventing the occurrence of P. aeruginosa bloodstream infection and improving the prognosis.

A Study on Isolation and Antibiotic Sensitivity Testing of Pseudomonas aeruginosa Isolated from Patients with Respiratory Tract Infection with Special Reference to Phenotypic and Genotypic Characterization of Extended Spectrum Beta Lactamases (ESBL)

Backgrounds: Pseudomonas aeruginosa is a classic opportunistic pathogen with innate resistance to many antibiotics and disinfectants. The lung is a main target for colonization and infection by the bacteria either in the context of a chronic, progressively deteriorating infectious and inflammatory pulmonary disease such as cystic fibrosis (CF) or in a more acute setting such as severe pneumonia in immunocompromised patients [1]. Aim and Objectives: To study the prevalence, virulence and the resistance pattern, phenotypic and genotypic characterization of P. aeruginosa from sputum samples. Materials and Methods: The present study was carried out with a total of 500 clinical sputum samples, which were received from patients, admitted to the various departments of Rajah Muthiah Medical College & Hospital, Annamalai University, Chidambaram. Result: Of the 500 samples subjected for isolation and identification of P. aeruginosa, 116 (23.20%) were positive. The isolated strains were tested for antibiotic sensitivity patterns. 93.10% of P. aeruginosa showed a maximum sensitivity to Ofloxacin, Norfloxacin and 86.20% of strains were highly resistant to Cefotaxime. The same isolates were also tested for phenotypic characterization of Extended Spectrum of Beta Lactamases by double disc synergy method against Cefotaxime and Clavulanic acid, according to the criteria of Hi-Media [2]. Of the resistant strains of P. aeruginosa isolated from sputum, 59% were positive for ESBL. The genotype characterization of ESBL P. aeruginosa showed 40% of CTX-M and 46.66% SHV gene. Conclusion: The present study strongly recommends for further checking of the antibiotic resistant strains of P. aeruginosa for phenotypic characterization of ESBL for effective treatment.

Role of MexA-MexB-OprM Efflux Pump System in Chronic Pseudomonas Aeruginosa Pulmonary Infection in Mice

In order to investigate the role of the MexA-MexB-OprM efflux pump system in the pathogenesis of Pseudomonas aeruginosa(PA)-induced pulmonary infection,pulmonary infection models were established by intratracheal injection of K767(wild type),nalB(MexA-MexB-OprM up-regulated mutant),and △m exB(knockout) strains,separately.All mice were treated with Meropenem(intraperitoneal injection,100 mg/kg body weight,twice every day),and strain-related pathology,bacteria count,cytokine level,myeloperoxidase(MPO,indicator of neutrophil recruitment) activity,and macrophage inflammatory protein-2(MIP-2) expression were evaluated at early(3rd day post-infection) and late(7th and 14th day post-infection) stages of infection.E-test showed that △mexB was more significantly sensitive to panipenan(ETP),meropenem(MP) and imipenem(IP) than K767 and nalB strains.There was no significant difference in sensitivity to cefepime(TM) among the three stains.In contrast to the K767 and nalB groups,the △ mexB group showed decreased bacteria burden over time and less extensive pathological change.Additionally,MPO activity and levels of inflammatory cytokines(IL-1b,IL-12,and TNF-α) were increased at the early stage(day 3) and decreased at the later stage(day 14).Serum MIP-2 expression level was steadily increased in all three groups from early to late stages,but significantly higher in △m exB group than in K767 and nalB groups(P<0.05).In conclusion,the MexA-MexB-OprM efflux pump system might play an important role in PA-induced chronic pulmonary infection.High expression of the MexA-MexB-OprM efflux pump could increase antibacterial resistance and promote infection.

Antibiotic resistance pattern of Pseudomonas aeruginosa wound isolates among Chinese burn patients:A systematic review and meta analysis

Objective:To investigate the resistance profiles to antimicrobial agents of wound-isolated Pseudomonas(P.)aeruginosa among Chinese burn patients.Methods:Electronic databases and manual search were used to identify eligible studies published since 2010.The objectives were pooled resistance rates for eleven common antimicrobial agents,estimated by a random-effects model.Subgroup analyses were conducted by stratifying the studies into three four-year periods based on year of isolation.Results:A total of 35 studies were included.Gentamicin had the highest pooled resistance rate(56%,95%CI 48%-64%),while meropenem had the lowest pooled resistance rate(29%,95%CI 20%-40%).There was an increasing trend of resistance to common antimicrobial agents of wound-isolated P.aeruginosa over a span of twelve years(2009-2020).There remained the highest risk of gentamicin resistance over time in China.Subgroup analyses indicated significantly higher resistances to ceftazidime and levofloxacin from 2017 to 2020.Conclusions:Enhanced resistance to common antimicrobial agents in wound-isolated P.aeruginosa presents a challenge in burn wound management in China's Mainland.Effective stewardship programs should be established based on corresponding resistance profiles,thereby optimizing treatment options for hospitalized burn patients.

Resistant patterns of Pseudomonas aeruginosa in a Malaysian teaching hospital

Objective:Pseudomonas aeruginosa is an opportunistic pathogen and the leading cause of nosocomial infections. Currently a notable increase in the prevalence of multidrug-resistant P.aeruginosa worldwide has been reported in hospitalized patients and was associated with high morbidity and mortality.Methods:A retrospective laboratory based analysis regarding the spectrum and distribution of P.aeruginosa from a wide range of clinical samples in Hospital Universiti Sains Malaysia since January 2003 to December 2007 was done.Results: Altogether,there were 2 308 clinical isolates analyzed.The main sources of P.aeruginosa were from swab,respiratory,urine and blood specimens which accounted for 28.2%,21.8%,13.2%and 12.8% respectively.Results showed significant reduction in percentage of resistant towards three antibiotic namely ciprofloxacin,ceftazidime and imipenem.However the percentage of pan-resistant P.aeruginosa increased steadily over these years.Conclusion:This data is helpful to the clinician in guiding the choice of appropriate antibiotic to treat P.aeruginosa infection.At the same time,it warrants a more aggressive infection control activity to be implemented to control the spread of pan resistant strain in this centre.

Other Possible Causes of a Well-Publicized Outbreak of <i>Pseudomonas aeruginosa</i>Following Arthroscopy in Texas

Background: Seven patients at a hospital in Houston, TX, were diagnosed during a two-week period in 2009 with joint space infection of pansusceptible P. aeruginosa following arthroscopic procedures of the knee or shoulder. Tosh et al. (2011), who investigated and published the principal report discussing this bacterial outbreak, conclude that its most likely cause was the improper reprocessing of certain reusable, physically-complex, heat-stable arthroscopic instruments used during these arthroscopic procedures. These reusable instruments reportedly remained contaminated with remnant tissue, despite diligent efforts by the hospital to clean their internal structures. This retained bioburden presumably shielded the outbreak’s strain of embedded P. aeruginosa from contact with the pressurized steam, reportedly resulting in ineffective sterilization of these arthroscopic instruments and bacterial transmission. Objectives: First, to clarify which specific sterilization methods, in addition to steam sterilization, Methodist Hospital employed to process its reusable arthroscopic instrumentation at the time of its outbreak, in 2009;second, to evaluate Tosh et al.’s (2011) conclusion that ineffective steam sterilization due to inadequate cleaning was the most likely cause of this hospital’s outbreak;third, to consider whether any other hitherto unrecognized factors could have plausibly contributed to this outbreak;and, fourth, to assess whether any additional recommendations might be warranted to prevent disease transmission following arthroscopic procedures. Methods: The medical literature was reviewed;some of the principles of quality assurance, engineering and a root-cause analysis were employed;and Tosh et al.’s (2011) findings and conclusions were reviewed and compared with those of other published reports that evaluated the risk of disease transmission associated with the steam sterilization of physically-complex, heat-stable, soiled surgical instruments. Results and Conclusion: Reports documenting outbreaks of P. aeruginosa or another vegetative bacterium associated with the steam sterilization of inadequately cleaned surgical or arthroscopic instruments are scant. This finding—coupled with a number of published studies demonstrating the effective steam sterilization of complex instruments contaminated with vegetative bacteria mixed with organic debris, or, in one published series of tests, with resistant bacterial endospores coated with hydraulic fluid—raises for discussion whether Methodist Hospital’s outbreak might have been due to one or more factors other than, or in addition to, that which Tosh et al. (2011) conclude was its most likely cause. An example of such a factor not ruled out by Tosh et al. (2011) findings would be the re-contamination of the implicated arthroscopic instruments after sterilization. The specific methods that Methodist Hospital employed at the time of its outbreak to sterilize some of its arthroscopic instrumentation remain unclear. A number of additional recommendations are provided to prevent disease transmission following arthroscopic procedures.

Multidrug resistant Psudomonas aeruginosa infections complicating surgical wounds and the potential challenges in managing post-operative wound infections:University of Calabar Teaching Hospital experience

Objective:To ascertain the antimicrobial susceptibility profile of Pseudomonas aeruginosa(P. aeruginosa) recovered from surgical site infections(SSIs).Methods:The study was retrospective in nature and was compiled for a period of five years(1st February,2004-31st January,2009).Data were generated from the culture of post-operative wound swab specimens by the microbiology laboratory of University of Calabar Teaching Hospital,Relevant information from the patients’ records was compiled,such as age,gender,type of surgical procedure,microorganisms recovered and their antibiotic sensitivity patterns.Obtained data was analysed by using Epi Info 6 statistical software.Results:Of the 4 533 wound swab specimens processed,673 were culture positive and P. aeruginosa was recovered from 13.1%of the culture positive specimens with its rate of recovery decreasing with age progression(P【0.05) but with no gender difference(P】0.05).Most of the P. aeruginosa isolates were from general surgery wards and least from orthopaedic wards.Ofloxacin, ceftriaxone and augmentin were the most active antibiotics while ampicillin,tetracycline and cotrimoxazole were the least active antibiotics,with no antibiotic having a 100%activity against the organism.Conclusions:In view of the high resistance displayed by P.aeruginosa recovered from SSIs,adequate antiseptic procedures should be entrenched to avoid colonization of surgical wounds by this microorganism as well as others with similar sensitivity profile.Ofloxacin, ceftriaxone and augmentin may be considered for prevention of P.aeruginosa infection.

Pseudomonas aeruginosa ventilator associated pneumonia: improved outcomes with earlier follow-up

It is not clear what is the appropriate timing to follow-up patients with ventilator-associated pneumonia (VAP) and Clinical Pulmonary Infe- ction Score >6 between days 3-5 of an appro- priate antibiotic treatment. We studied 122 patients with Pseudomonas aeruginosa VAP. A follow-up respiratory sample was collected on days three or five ( “day-three” and “day-five” group ) and treatment was modified 48h later. Molecular typing identified super-infections or persistence. For serial data another respiratory sample was collected, on day three from the “day-five” group and on day five from the “day-three” group. Sixty patients, in the “day- three” group compared to 62 in the “day-five” group, had reduced fourteen-day mortality ( 18.3% and 38.7%;p=0.01 ) and fewer days in intensive care unit (17.2 ± 4.3 compared to 27.3 ± 4.7, p6, improved fourteen-day mortality and shorter duration of stay in health-care facilities were observed with earlier follow-up.

Choroidal metastatic mucinous abscess caused by Pseudomonas aeruginosa:A case report

BACKGROUND Pseudomonas aeruginosa(P.aeruginosa)is considered a common pathogenic bacterium.Choroidal metastatic mucinous abscess caused by P.aeruginosa is rarely reported.CASE SUMMARY We describe the diagnostic and treatment processes of a case involving a complex choroidal space-occupying lesion.Our analyses of early clinical manifestations revealed a high possibility of choroidal melanoma,as indicated by the choroidal space-occupying lesion and uveitis.Further magnetic resonance imaging results revealed no positive evidence for the diagnosis of choroidal melanoma.The exact properties of the space-occupying lesion could not be ascertained prior to surgery.However,the lesion was subsequently confirmed as a metastatic abscess by diagnostic vitrectomy.The occupying lesion was found to occupy 75%of the vitreous cavity in the surgery.The entire white viscous tissue was completely removed,and the necrotic retina was cleaned up.After surgery,microbiological culture revealed mucoid P.aeruginosa,which was sensitive to a variety of antibiotics.The bacterial infection grew and disseminated towards the outside of the eye.After the fifth injection,the left eye was successfully retained.CONCLUSION This is a peculiar case because a huge,local,space-occupying lesion had formed due to the dissemination of low-toxic mucinous P.aeruginosa in the blood from the lungs to the choroid.After surgical removal,the bacteria were able to re-grow;thus,local infection re-spread following surgery.The patient lost vision,but we managed to retain the full structure of the eyeball and eliminated the focus of infection.

Pseudomonas aeruginosa-related effusive-constrictive pericarditis diagnosed with echocardiography:A case report

BACKGROUND Effusive-constrictive pericarditis(ECP)is an uncommon pericardial syndrome.Careful echocardiographic examination may provide helpful information not only for diagnosing but also for managing ECP.ECP has various etiologies;however,Pseudomonas aeruginosa(P.aeruginosa)infection has not been reported as a cause to date.Herein,we present a rare case of ECP caused by P.aeruginosa infection,which was followed up using echocardiography.CASE SUMMARY A 30-year-old man was admitted to our hospital with a 2-mo history of cough,dyspnea,bloating,palpitations,and lower-extremity edema.The patient was initially diagnosed with pericardial effusion by transthoracic echocardiography.Drainage of pericardial effusion was performed to relieve the clinical symptoms.A follow-up echocardiogram showed that the pericardial effusion had decreased;however,the right atrial pressure continued to increase,and signs of constrictive pericarditis were observed upon a more comprehensive inspection.Therefore,the diagnosis of ECP was established based on the comprehensive pre-and postpericardiocentesis echocardiographic findings.An urgent pericardectomy was subsequently performed,which significantly relieved the patient's clinical symptoms,and the signs of pericardial constriction on echocardiography improved.Pericardial effusion and pericardial culture showed growth of P.aeruginosa.CONCLUSION ECP induced by P.aeruginosa infection remains a rare disease.The presence of echocardiographic features of constrictive pericarditis after pericardiocentesis therapy is highly indicative of ECP.

重症医学科铜绿假单胞菌血流感染的危险因素分析及风险预测模型

目的研究重症医学科(intensive care unit,ICU)铜绿假单胞菌血流感染的危险因素及构建风险预测模型。方法回顾调查铜绿假单胞菌血流感染患者资料。使用logistic回归分析进行单因素和多因素筛选出独立危险因素,构建铜绿假单胞菌血流感染风险预测评分模型。结果合并其他疾病、入住ICU时间、机械通气、APACHEⅡ评分是ICU铜绿假单胞菌血流感染的独立危险因素。Logistic回归模型Logit(P)=-69895+1.616×合并其他疾病+2.610×入住ICU时间+1.846×机械通气+2.831×APACHEⅡ评分。ROC曲线下面积为0.712,灵敏度为88.2%,特异度为75.2%,95%CI为[0.612,0.854],最佳截断值为13.412。结论合并其他疾病、入住ICU时间、机械通气、APACHEⅡ评分是ICU铜绿假单胞菌血流感染的独立危险因素。Logistic回归模型便于感染风险的预测。

铜绿假单胞菌-甘露糖敏感血细胞凝集素抗肿瘤的作用机制及临床应用

铜绿假单胞菌-甘露糖敏感血细胞凝集素(PA-MSHA)在抗肿瘤领域的应用不断增加。PA-MSHA可以通过抑制表皮生长因子受体(EGFR)通路促进肿瘤细胞凋亡、抑制肿瘤细胞侵袭和迁移、分化以及改变耐药和细胞上皮-间充质转化(EMT)状态,同时PA-MSHA也通过Toll样受体(TLR)增强巨噬细胞和T细胞对肿瘤细胞的免疫杀伤和抑制。该文梳理并综述关于PA-MSHA抗肿瘤的机制及临床应用,认为PA-MSHA通过作用于细胞甘露糖基的调节过程改变了EGFR和TLR蛋白的糖基化。PA-MSHA可能作用的细胞膜蛋白包括更多的高甘露糖基信号通路受体,阐明PA-MSHA和甘露糖基之间的深层次关系对PA-MSHA的机制研究及临床应用意义重大。

支气管扩张症合并铜绿假单胞菌感染:2012-2022年的文献计量学分析及可视化研究

目的探讨支气管扩张症(支扩症)合并铜绿假单胞菌(PA)感染领域过去十年的研究现状及发展趋势,为该领域的科学研究提供新的思路和策略。方法以“bronchiectasis”or“cystic fibrosis”or“non-cystic fibrosis bronchiectasis”and“Pseudomonas aeruginosa”检索2012—2022年Web of Science Core Collection(WoSCC)发表类型为论著和综述的英文文献,利用HisCite、VOSviewer和Citespace软件对文献发文量、期刊、作者和关键词等进行文献计量学及可视化分析。结果全球共5824篇支扩症合并PA感染的文章发表在1103种期刊上,年均发文量较稳定,以呼吸系统和微生物学期刊为主。共96个国家和地区、5005个机构、21769名作者在该领域发表文章,美国发表文章最多并构建了全球最大合作网络。该领域研究主要集中在肺囊性纤维化,聚类主题包括PA在宿主的适应和进化、炎症反应、抗生素耐药、临床结局和预后。慢性气道感染及各类临床评分标准是近年较为突出的主题。结论支扩症合并PA感染是呼吸系统和微生物学的关注重点,研究主要集中在细菌-宿主相互作用和临床影响,建议中国学者未来更多参与这一领域的基础和临床研究。

Two bacterial infection models in tree shrew for evaluating the efficacy of antimicrobial agents

Animal models are essential for the development of new anti-infectious drugs.Although some bacterial infection models have been established in rodents,small primate models are rare.Here,we report on two bacterial infection models established in tree shrew（Tupaia belangeri chinensis）.A burnt skin infection model was induced by dropping 5×106 CFU of Staphylococcus aureus on the surface of a wound after a third degree burn.This dose of S.aureus caused persistent infection for 7 days and obvious inflammatory response was observed 4 days after inoculation.A Dacron graft infection model,2×106 CFU of Pseudomonas aeruginosa also caused persistent infection for 6 days,with large amounts of pus observed 3 days after inoculation.These models were used to evaluate the efficacy of levofloxacin（LEV） and cefoperazone（CPZ）,which reduced the viable bacteria in skin to 4log10 and 5log10 CFU/100 mg tissue,respectively.The number of bacteria in graft was significantly reduced by 4log10 CFU/mL treatment compared to the untreated group（P0.05）.These results suggest that two bacterial infection models were successfully established in tree shrew using P.aeruginosa and S.aureus.In addition,tree shrew was susceptible to P.aeruginosa and S.aureus,thus making it an ideal bacterial infection animal model for the evaluation of new antimicrobials.

铜绿假单胞菌噬菌体PaP1生物学特性的研究

目的 确定铜绿假单胞菌噬菌体PaP1的形态大小、核酸类型、裂菌特性、最佳感染复数和一步生长曲线等基本生物学特性。方法 对CsCl梯度离心纯化后的噬菌体PaP1颗粒进行电镜观察;提取PaP1基因组核酸,通过限制性内切酶图谱分析其核酸类型;制备PaP1的单个噬斑,观察噬斑特点;按照感染复数(MOI)分别为0 0 0 0 1、0 0 0 1、0 0 1、0 1、1和10加入噬菌体纯培养液和宿主菌,3 7℃160r/min培养3 5h后测定噬菌体滴度;加入噬菌体及宿主菌使MOI =10 ,3 7℃温育15min后进行一步生长实验,于0时刻和每隔10min取样5 0 μl测定上清中噬菌体滴度。结果 PaP1噬菌体头部呈多面体立体对称,直径约70nm ,无囊膜,有一个约60nm长的尾;PaP1噬斑直径约2mm ,圆形透明;当MOI为0 0 1时PaP1感染其宿主菌产生的子代噬菌体滴度最高;根据一步生长实验结果绘制出了一步生长曲线。结论 PaP1属于肌尾科裂菌性噬菌体,其基因组为双链DNA分子;最佳感染复数为0 0 1,感染宿主菌的潜伏期是2 0min ,爆发期是40min ,平均爆发量约为65。

铜绿假单胞菌噬菌体PaP2生物学特性的研究

目的 确定铜绿假单胞菌噬菌体PaP2的形态与大小、裂菌特性、最佳感染复数、一步生长特性等基本的生物学特性。方法 电镜观察纯化噬菌体颗粒 ;制备PaP2噬斑 ,观察其特点 ;提取噬菌体感染的细菌基因组 ,用SmaⅠ酶切 ,通过脉冲场电泳观察酶切产物的带型特点 ;测定不同感染复数 ,培养 3 5h后细菌 噬菌体液中的噬菌体滴度 ;加入宿主菌及噬菌体使MOI =10 ,进行一步生长实验 ,在 0时刻和每隔 15min测定噬菌体滴度。结果 噬菌体PaP2头部直径约为 5 2nm ,无囊膜 ,有一短尾 ;噬斑雾状半透明 ,直径约 1～ 2mm ;被噬菌体感染的宿主菌基因组的SmaⅠ酶切产物带型 ,比未感染宿主菌的多出了 1条大于噬菌体基因组的片段 ;当MOI =10时宿主菌产生的子代噬菌体滴度最高 ;绘制出了一步生长曲线。结论 PaP2属短尾噬菌体科 ,是溶原性噬菌体 ;最佳感染复数是 10 ;感染宿主菌的潜伏期是 75min ,裂解期是 90min ,平均裂解量是 3

PA-MSHA疫苗对严重创伤患者并发肺部感染的预防作用

目的研究绿脓杆菌菌毛株(PA-MSHA)疫苗对严重创伤患者免疫功能影响和对并发肺部感染的预防作用。方法选择ICU住院严重创伤患者共55例,随机分为两组:①对照组:27例,给予常规治疗;②疫苗组:28例,除常规救治外,从入院当天给予皮下注射PA-MSHA疫苗1．0 mL,1次/d,连续注射14 d。分别在入院当天和入院第14天取静脉血测定免疫功能指标,并统计入院第14天内并发肺部感染的发生率。结果疫苗组在入院第14天时血清IgG、补体C3和C4、NK(自然杀伤细胞)活性、CD3、CD4和CD4/CD8比值均比入院当天有明显升高(P＜0．01),而对照组仅有补体C3值在入院第14天出现明显升高(P＜0．05);对照组在入院第14天内并发肺部感染发生率为44．4%,疫苗组为21．4%,疫苗组肺部感染发生率明显低于对照组(P＜0．01)。结论PA-MSHA疫苗能够明显提高严重创伤患者机体免疫功能,并且能一定程度预防肺部感染的发生率。

铜绿假单胞菌噬菌体PaP3生物学特性的研究

目的测定铜绿假单胞菌噬菌体PaP3的最佳感染复数、一步生长曲线和吸附K值及交叉吸附K值等基本生物学特性。方法按照感染复数(MOI)分别为0·0001、0·001、0·01、0·1、1和10加入噬菌体纯培养液和宿主菌,充分裂解细菌后,测定噬菌体滴度;以MOI=10的比例加入噬菌体及宿主菌,进行一步生长实验;纯化PaP3颗粒,免疫家兔,获得抗血清,通过中和反应实验测定PaP3和其抗血清之间的吸附反应常数K值。同时,利用抗血清交叉中和试验确定本室分离的三株噬菌体之间的血清学关系。结果当MOI=0·001时PaP3感染其宿主菌产生的子代噬菌体滴度最高;根据一步生长实验结果绘制一步生长曲线;通过血清交叉中和反应得出不同的吸附常数。结论PaP3最佳感染复数为0·001,感染宿主菌的潜伏期是20min,爆发期是60min,平均爆发量约为31,其抗血清反应的吸附常数K值为262。

PA-MSHA抗肿瘤效应的免疫机制研究

目的研究铜绿假单胞菌甘露糖敏感血凝菌毛株(pseudomonas aeruginosa-mannose sensitive hemagglutinin,PA-MSHA)处理树突状细胞(dendritic cells,DCs)后对其功能及激活T细胞杀伤肿瘤细胞效应的影响。方法取小鼠骨髓来源的DC,观察PA-MSHA体外处理后对DC表面分子、吞噬功能及T细胞杀伤功能的影响。结果 PA-MSHA处理的DC其表面分子CD40、I-E表达显著上升,吞噬功能显著下降,由DC诱导的活化T细胞对肿瘤细胞的杀伤效应显著高于对照组。结论 PA-MSHA能有效促进DC成熟并增强抗肿瘤免疫效应。