本文選題：噬菌體 + 鮑曼不動(dòng)桿菌　； 參考：《吉林大學(xué)》2017年碩士論文

【摘要】：鮑曼不動(dòng)桿菌(Acinetobacter baumannii)是不動(dòng)桿菌屬重要成員之一,為專性需氧的革蘭染色陰性桿菌,廣泛存在于自然界的土壤和水中,也可存在健康人的腸道中。流行病學(xué)資料證實(shí),鮑曼不動(dòng)桿菌是引起醫(yī)院內(nèi)感染重要的條件致病菌之一,鮑曼不動(dòng)桿菌引起感染的對(duì)象主要為接受化療的腫瘤患者、器官移植病人、嚴(yán)重外傷和有慢性病的老年患者。此外,鮑曼不動(dòng)桿菌耐藥菌株和多重耐藥菌株的不斷出現(xiàn)使得抗生素療法的實(shí)際功效明顯下降,同時(shí)鮑曼不動(dòng)桿菌可將其攜帶的耐藥基因通過接合、轉(zhuǎn)化和轉(zhuǎn)導(dǎo)的方式傳遞其他細(xì)菌,造成細(xì)菌耐藥的進(jìn)一步傳播。細(xì)菌耐藥性的日趨嚴(yán)重和普遍性已成為全球的公共衛(wèi)生問題。近年來,利用噬菌體預(yù)防和控制細(xì)菌感染的噬菌體療法重新引起有關(guān)人士的關(guān)注。本項(xiàng)研究的目的是通過分離鑒定鮑曼不動(dòng)桿菌噬菌體并對(duì)其生物學(xué)特征和遺傳信息進(jìn)行分析,為今后噬菌體用于鮑曼不動(dòng)桿菌引起的感染提供依據(jù)。本研究采用常規(guī)方法以鮑曼不動(dòng)桿菌為宿主菌從環(huán)境污水中分離到5株裂解性噬菌體,分別命名為噬菌體LZ12、LZ22、LZ35、LZ57和LZ78。電鏡觀察發(fā)現(xiàn),噬菌體LZ12、LZ22、LZ35和LZ57的形態(tài)學(xué)特征符合肌尾病毒科(Myoviridae family)噬菌體,而LZ78則屬于足尾病毒科(Podoviridae family)噬菌體。在本研究中,我們對(duì)噬菌體LZ35的生物學(xué)特性和基因組序列進(jìn)行了初步的分析。結(jié)果顯示,噬菌體LZ35的頭部呈二十面體立體對(duì)稱、直徑約47 nm,尾部為伸縮性、長約56 nm。噬菌體LZ35的最佳感染復(fù)數(shù)(MOI)為0.01,一步生長曲線表明,LZ35的潛伏期為10 min,爆發(fā)量為149 pfu/cell。LZ35在p H4~10和孵育50℃1h的條件下仍能保持其生物學(xué)活性。酶切電泳顯示,噬菌體LZ35的基因組中含有Eco RⅠ、BglⅡ、Eco RⅤ、HindⅢ、NdeⅠ、PstⅠ和XbaⅠ的酶切位點(diǎn)。提取和純化的噬菌體LZ35基因組提交至金維智基因技術(shù)服務(wù)公司進(jìn)行測(cè)序。結(jié)果表明,噬菌體LZ35基因組呈線性雙鏈DNA、大小為44,885 bp,G+C含量是37.95%,未發(fā)現(xiàn)t RNA�；蜃⑨岋@示,LZ35基因組含有83個(gè)編碼序列(coding sequences,CDS),其中22個(gè)編碼序列可預(yù)測(cè)其功能,61個(gè)編碼序列為未知基因。利用BLASTn軟件分析比對(duì)表明,噬菌體LZ35的基因組與鮑曼不動(dòng)桿菌噬菌體IME-AB2(登錄號(hào):JX976549.1)和鮑曼不動(dòng)桿菌噬菌體YMC-13-01-C62(登錄號(hào):KJ817802.1)具有很高的同源性(分別為97%和99%)。依據(jù)鮑曼不動(dòng)桿菌噬菌體基因組中的RNA聚合酶核苷酸序列所繪制的進(jìn)化樹發(fā)現(xiàn),噬菌體LZ35與鮑曼不動(dòng)桿菌噬菌體YMC11/12/R12的進(jìn)化關(guān)系最近,在同一分支上。噬菌體LZ35的全基因組序列已提交至Gen Bank,登錄號(hào):KU510289.1。
[Abstract]:Acinetobacter Baumannii is one of the most important members of Acinetobacter Baumannii. Acinetobacter Baumannii is a specific aerobic gram-negative bacilli, widely found in the soil and water of nature, and in the intestinal tract of healthy people. Epidemiological data confirm that Acinetobacter baumannii is one of the most important opportunistic pathogens causing nosocomial infection. Acinetobacter baumannii causes infection mainly among cancer patients receiving chemotherapy and organ transplant patients. Elderly patients with severe trauma and chronic disease. In addition, the continuous emergence of Acinetobacter baumannii resistant strains and multidrug resistant strains significantly reduced the actual efficacy of antibiotic therapy, and Acinetobacter baumannii was able to conjugate the drug-resistant genes it carries. The transformation and transduction of other bacteria causes the further spread of drug resistance. The increasing severity and universality of bacterial resistance has become a global public health problem. In recent years, bacteriophage therapy for the prevention and control of bacterial infection has attracted renewed attention. The purpose of this study was to isolate and identify the bacteriophage of Acinetobacter baumannii and to analyze its biological characteristics and genetic information so as to provide the basis for the use of phage in the future infection caused by Acinetobacter baumannii. In this study, five lytic bacteriophages were isolated from environmental sewage with Acinetobacter baumannii as host bacteria and named as LZ12, LZ22, LZ35, LZ57 and LZ78, respectively. The morphological characteristics of the bacteriophage LZ12, LZ22, LZ35 and LZ57 were similar to that of Myoviridae family, while LZ78 belonged to Podoviridae family. In this study, we analyzed the biological characteristics and genomic sequence of phage LZ35. The results showed that the head of bacteriophage LZ35 was icosahedron stereomorphic, with a diameter of 47 nm, and a retractility of the tail with a length of 56 nm. The one step growth curve showed that the incubation period of LZ35 was 10 min, and the explosion amount of 149 pfu/cell.LZ35 could maintain its biological activity at pH 4N 10 and incubated at 50 鈩，

本文編號(hào)：1916137