IMPROVING DIAGNOSTIC ACCURACY AND DEFINING THE EPIDEMIOLOGY OF CELLULITIS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 蜂窝织炎是一种常见的皮肤及其下面组织的感染。2004年，美国有24万名成人因蜂窝织炎住院治疗，花费了37亿美元。然而，罗切斯特大学的一项初步研究显示，在入院的推定为蜂窝组织炎的患者中，有20%被错误诊断。我们假设，可视化临床决策支持系统将帮助医生诊断蜂窝织炎，这将有助于避免不必要的住院、抗生素管理和医疗支出。 从历史上看，A组链球菌是蜂窝组织炎最常见的原因，金黄色葡萄球菌导致了少数病例。与这种观点相反，罗兰·米勒博士和他的同事回顾文献发现，在接受针吸培养的蜂窝组织炎患者中，金黄色葡萄球菌与A组链球菌分离株的比例大于3比1。 20世纪40年代，当青霉素被引入治疗葡萄球菌感染时，金黄色葡萄球菌中就出现了抗生素耐药性，它限制和重塑了治疗方案。社区暴发和社区相关MRSA疾病的急剧增加发生在许多人群中，包括：囚犯、军事人员、运动员、日托参与者和家庭。CA-MRSA在洛杉矶县流行，通常会在与所谓的高危人群没有接触的人中引起感染。 蜂窝织炎和CA-MRSA的交叉是很重要的。鉴于蜂窝组织炎最常见的已知原因是金黄色葡萄球菌，而社区大多数金黄色葡萄球菌感染是由CA-MRSA引起的，我们假设蜂窝组织炎的经验性治疗可能需要结合MRSA的治疗。 这项研究的目的是确定疑似蜂窝组织炎或丹毒的患者诊断的准确性，确定与蜂窝组织炎感染相关的危险因素，并分析蜂窝组织炎患者中CA-MRSA定植的分子流行病学。 我们将在1：2配对病例对照研究中招募160名住进港湾-加州大学洛杉矶分校住院病房的患者。首先，我们将招募60名疑似蜂窝织炎患者。我们预计60名患者中有83%会患上蜂窝组织炎。蜂窝织炎病例被定义为住进住院病房的患者，经皮肤科医生确认诊断为无并发症的蜂窝织炎或丹毒。将不会有基于性别或种族/民族的入学限制。对照按1：2的比例匹配，被定义为住进住院病房的未感染的受试者，他们与蜂窝组织炎病例通过3个标准匹配：年龄、性别和种族/民族。 研究协调员将确定急诊科入院的初步诊断为蜂窝织炎或丹毒的患者。如果患者同意，研究协调员将填写一份调查问卷，拍摄皮肤损害的照片，收集鼻部和腹股沟皱折细菌拭子培养，收集相关的过去病史，并进行定向体检。研究协调员还将记录实验室数据，收集住院住院医生使用计算机化临床决策支持工具生成的数据。失去隐私是主要的风险，虽然参与者没有直接的好处，但参与可能会帮助未来的蜂窝组织炎患者。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cellulitis is a common infection of the skin and its underlying tissues. In 2004, $3.7 billion were spent on 240,000 adult hospitalizations for cellulitis in the United States. However, a University of Rochester pilot study showed that 20% of patients admitted to the hospital with a presumed diagnosis of cellulitis were diagnosed incorrectly. We hypothesize that a visual clinical decision support system (VisualDx) will assist physicians in diagnosing cellulitis, which will help avoid unnecessary hospitalizations, antibiotic administration, and healthcare spending. Historically, group A streptococci was the most common cause of cellulitis, with Staph aureus responsible for a minority of cases. Contrary to this view, Dr. Loren Miller (co-investigator) and colleagues' review of the literature found that among patients with cellulitis who undergo needle aspiration cultures, the ratio of Staph aureus to group A streptococcal isolates is greater than three to one. Antibiotic resistance among Staph aureus emerged as soon as penicillin was introduced to treat staphylococcal infections in the 1940s, and it restricts and reshapes therapeutic options. Community outbreaks and dramatic increase of community-associated MRSA (CA-MRSA) disease have occurred in numerous populations including: prisoners, military personnel, athletes, daycare attendees, and families. CA-MRSA is endemic in Los Angeles County and typically causes infections in persons without contact with so-called "at risk" populations. The intersection of cellulitis and CA-MRSA is important. Given the most common known cause of cellulitis is Staph aureus, and the majority of Staph aureus infections from the community are caused by CA-MRSA, we hypothesize that empiric treatment of cellulitis may need to incorporate treatment for MRSA. The aims of this study are to determine the accuracy of diagnosis of patients with suspected cellulitis or erysipelas (a similar superficial infection often caused by Streptococcus pyogenes), to identify risk factors associated with cellulitis infection, and to analyze the molecular epidemiology of CA-MRSA colonization among patients with cellulitis. We will enroll 160 patients admitted to Harbor-UCLA inpatient wards in a 1:2 paired case-control study. First, we will enroll 60 patients with suspected cellulitis. We anticipate 83% of 60 patients (n=50) will have cellulitis. Cellulitis cases are defined as patients admitted to the inpatient wards with a dermatologist-confirmed diagnosis of uncomplicated cellulitis or erysipelas. There will be no gender or racial/ethnic-based enrollment restrictions. Controls, matched at a 1:2 ratio, are defined as uninfected subjects admitted to the inpatient wards who are matched to cellulitis cases by 3 criteria: age (within 5 years), gender, and race/ethnicity. The study coordinator will identify patients admitted from the Emergency Department with a primary diagnosis of cellulitis or erysipelas. If the patient provides consent, the study coordinator will administer a questionnaire, photograph skin lesions, collect nasal and inguinal fold bacterial swab cultures, collect pertinent past medical history, and perform a directed physical exam. The study coordinator will also record laboratory data, collect data generated by inpatient resident physicians utilizing the computerized clinical decision support tool. Loss of privacy is the main risk, and while there are no direct benefits for the participant, participating may help future patients with cellulitis.