Spread of Community-Acquired MRSA Among Household Contacts

社区获得性 MRSA 在家庭接触者中的传播

• 批准号: 7262871
• 负责人: Robert S. Daum
• 金额: $ 60万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-05-15 至 2011-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7262871
• 关键词: Adult; Affect; Anatomy; Antibiotic susceptibility; Antibiotics; Be++ element; Beryllium; Cell Line; Chicago; Child; Chronic Disease; Clinical; Communities; Containment; Cytolysis; DNA Sequence; Development; Disease; Disease Outbreaks; Elements; Emerging Communicable Diseases; Environment; Epidemic; Epidemiology; Evolution; Frequencies; Genes; Genetic; Genotype; Guidelines; Hand; Healthcare; Hospitals; Household; Indium; Individual; Infection; Investigation; Knowledge; Lactams; Locales; Los Angeles; Mammalian Cell; Methicillin; Methicillin Resistance; Methods; Mobile Genetic Elements; Monobactams; Movement; Natural History; Nature; Nose; Numbers; Panton-Valentine leukocidin; Pathogenesis; Patients; Pattern; Personal Satisfaction; Pneumonia; Polymerase Chain Reaction; Predisposition; Prevalence; Pulsed-Field Gel Electrophoresis; Rate; Relative (related person); Reporting; Research Personnel; Resistance; Risk; Risk Factors; Sea; Sepsis Syndrome; Site; Skin; Soft Tissue Infections; Staphylococcus aureus; Syndrome; Testing; Therapeutic; Toxin; United States; Vanadium; antimicrobial; genetic element; indexing; member; methicillin resistant Staphylococcus aureus; molecular size; novel; pathogen; prevent; programs; secondary infection; transmission process

DESCRIPTION (provided by applicant): Epidemic Community-Acquired Methicillin-resistant Staphylococcus aureus (MRSA) is an emerging infectious disease in previously healthy children and adults without risk factors for MRSA acquisition. These new community-acquired MRSA (CA-MRSA) strains differ from hospital-acquired MRSA (HA-MRSA) strains in that they are often susceptible to non-B-lactam antibiotics, cause disease similar to community-acquired methicillin-susceptible S. aureus (CA-MSSA), and contain the genes encoding the cytolytic toxin, Panton- Valentine leukocidin. When the genetic element responsible for the antibiotic susceptibility patterns in these CA-MRSA strains was characterized, now called "staphylococcal chromosomal cassette mec" type IV or SCCmec type IV, it was realized that a distinct phenomenon had occurred not involving spread of HA-MRSA into the community. Outbreaks of skin and soft tissue infections, necrotizing pneumonia, and sepsis syndromes due to CA-MRSA have been reported with increasing frequency. We are seeking crucial information on how to prevent spread of these strains and how to treat infected and colonized individuals. The natural history of CA-MRSA colonization among household members and its association with infection are issues that must be defined in order to develop effective containment, preventative, and therapeutic strategies. In order to define the transmissibility of CA-MRSA strains, household contacts of an index case with CA- MRSA disease will be tested for colonization by CA-MRSA. Rates of CA-MRSA carriage among household contacts will be compared with rates of HA-MRSA carriage among household contacts of an index patient with HA-MRSA. The frequency with which CA-MRSA strains cause disease will be assessed prospectively by determining the secondary attack rate of disease and this will be compared to that of HA-MRSA. The predominant site of CA-MRSA will also be determined by culturing both the nose and the hand. All strains will be genetically characterized by pulsed-field gel electrophoresis, multi-locus sequence typing, SCCmec typing, and lukS-PV/lukF-PV PCR to determine the clonal repertoire of CA-MRSA strains and assess relatedness among household contacts. The knowledge to be gained from this study is crucial to guide further strategies to deal with the CA-MRSA epidemic. Defining the colonization frequency among household contacts of an index case, the secondary attack rate by CA-MRSA, and the predominant site of carriage will aid in development of containment, preventative, and therapeutic management guidelines.

描述（由申请人提供）：流行性社区获得性耐甲氧西林金黄色葡萄球菌 (MRSA) 是一种新出现的传染病，发生在既往健康的儿童和成人中，没有 MRSA 感染的危险因素。这些新的社区获得性 MRSA (CA-MRSA) 菌株与医院获得性 MRSA (HA-MRSA) 菌株不同，因为它们通常对非 B-内酰胺抗生素敏感，引起与社区获得性甲氧西林敏感金黄色葡萄球菌 (CA-MSSA) 类似的疾病，并且含有编码细胞溶解毒素 Panton-Valentine 杀白细胞素的基因。当对这些 CA-MRSA 菌株（现在称为“葡萄球菌染色体盒 mec”IV 型或 SCCmec IV 型）中负责抗生素敏感性模式的遗传元件进行表征时，人们意识到已经发生了一种不涉及 HA-MRSA 传播到社区的独特现象。 CA-MRSA 引起的皮肤和软组织感染、坏死性肺炎和脓毒症综合征的爆发频率不断增加。我们正在寻求有关如何防止这些菌株传播以及如何治疗受感染和定植个体的重要信息。 CA-MRSA 在家庭成员中定植的自然史及其与感染的关系是必须确定的问题，以便制定有效的遏制、预防和治疗策略。为了确定 CA-MRSA 菌株的传播能力，将对 CA-MRSA 疾病指示病例的家庭接触者进行 CA-MRSA 定植检测。将家庭接触者中 CA-MRSA 携带率与 HA-MRSA 指标患者的家庭接触者中 HA-MRSA 携带率进行比较。 CA-MRSA 菌株引起疾病的频率将通过确定疾病的继发发病率进行前瞻性评估，并将其与 HA-MRSA 进行比较。 CA-MRSA 的主要位点也将通过培养鼻子和手来确定。所有菌株都将通过脉冲场凝胶电泳、多位点序列分型、SCCmec 分型和 lukS-PV/lukF-PV PCR 进行遗传表征，以确定 CA-MRSA 菌株的克隆库并评估家庭接触者之间的相关性。从这项研究中获得的知识对于指导应对 CA-MRSA 流行的进一步策略至关重要。确定指示病例家庭接触者的定植频率、CA-MRSA 的继发感染率以及主要携带部位将有助于制定遏制、预防和治疗管理指南。