鲍曼不动杆菌临床分离株的耐药性及同源性分析

目的 通过对重庆医科大学附属第二医院近4年临床分离的103株鲍曼不动杆菌的耐药性和同源性分析,了解该院鲍曼不动杆菌的耐药性特点及院内感染流行状况.方法 2008年至2011年间该院临床科室分离的103株鲍曼不动杆菌,进行药敏试验并对耐药性分析;提取细菌基因组DNA,以随机扩增DNA多态性(RAPD)方法进行基因分型.结果 药敏试验结果显示分离出的103株菌呈现出高耐药率及多重耐药率的特点,其中对左氧氟沙星和亚胺培南的耐药性最低,分别为69.9％和57.3％.103株多重耐药鲍曼不动杆菌用RAPD分型共分为16种基因型:A～P,其中A型84株,为主要流行型别;B型3株;C型、G型各2株;其余12型各1株.结论 该院鲍曼不动杆菌具有多重耐药及高耐药率,可能存在以A型鲍曼不动杆菌克隆株传播方式的院内流行,临床上应加强对A型鲍曼不动杆菌的监控,采取有效的措施以预防院内感染的爆发流行.     

鲍曼不动杆菌耐药程度与其主动外排泵蛋白的相关性研究

目的:探讨鲍曼不动杆菌耐药程度与其主动外排泵蛋白的相关性。方法:首先用纸片扩散法检测64株临床鲍曼不动杆菌对8种抗菌药物的敏感性;将其分为A组(0～2种抗生素耐药)、B组(对3～5种抗生素耐药)和C组(对6～8种抗生素耐药);检测64株临床鲍曼不动杆菌对罗丹明6G的外排情况,筛选出罗丹明6G外排明显增加的菌株;并用逆转录-聚合酶链反应(RT-PCR)方法检测主动外排泵基因AdeABC的表达水平。结果:64株鲍曼不动杆菌中有4株对0～2种抗生素耐药(A组),对3～5种抗生素耐药的有33株(B组),对6～8种抗生素耐药的有27株(C组);多重耐药组鲍曼不动杆菌罗丹6G外排明显增高,外排程度A组相似文献   

鲍曼不动杆菌的基因分型及耐药性分析

目的分析上海某综合性医院不同科室来源的鲍曼不动杆菌菌株的同源性及耐药状况,了解鲍曼不动杆菌院内感染流行情况。方法采用重复序列PCR技术（REP-PCR）,对51株临床分离的鲍曼不动杆菌菌株进行基因分型,并用纸片扩散法进行药敏试验。结果51株鲍曼不动杆菌分为13个基因型,其中A型16株,为主要流行型别;C型、D型各6株;M型有5株;E型、F型和G型各3株;B型、H型和K型各2株;I型、J型、L型各1株。药敏试验结果显示分离出的菌株对常用抗菌药呈现出多重耐药的现象。其中对阿米卡星和亚胺培南的耐药性最低,均为33.3%;对头孢唑啉耐药性最高,为100%。结论鲍曼不动杆菌基因的同源性分析表明,该院存在着以A型鲍曼不动杆菌为主的感染流行,估计该型菌株可能以克隆株的形式播散。鲍曼不动杆菌的耐药性很强,应加强其耐药性监测,合理使用抗菌药物。     

2006-2010年舟山地区鲍曼不动杆菌感染动态观察

目的 了解舟山地区近5年鲍曼不动杆菌(Acinetobacter baumanii,Ab)的感染状况及对常见抗菌药物的耐药情况,为有效控制感染和治疗提供依据.方法 对2006年1月至2010年12月临床送检的血、尿及痰等各类标本进行细菌培养、分离与鉴定和药物敏感试验,细菌鉴定采用ATB-expression细菌鉴定仪,药敏试验采用其配套的PSE-5条.结果 2006-2010年共检出鲍曼不动杆菌696株.Ab主要分布于ICU (301,43.4％)和呼吸内科(132,19.0％)的送检标本.痰标本检出率最高,为524株(75.3％).Ab对除妥布霉素以外抗生素的耐药性呈逐年上升的趋势(P＜0.01).多重耐药鲍曼不动杆菌比例也逐渐增加.结论 鲍曼不动杆菌对临床常用抗菌药物的耐药性呈逐年上升趋势,多重耐药菌比例明显增加.碳青霉烯类抗生素仍是治疗Ab感染最敏感的药物.应加强鲍曼不动杆菌细菌耐药监测,进一步合理有效使用抗生素,以防止鲍曼不动杆菌的传播,降低多重耐药鲍曼不动杆菌交叉感染的发生.     

鲍曼不动杆菌IRS-PCR基因分型研究

目的 用低频限制性位点聚合酶链反应(IRS-PCR)对鲍曼不动杆菌进行基因分型,分析基因型与鲍曼不动杆菌耐药谱的关系,并初步探讨其在分子流行病学中的作用.方法 随机收集2008年8月至2009年8月临床分离的73株鲍曼不动杆菌,采用K-B法进行药物敏感试验确定鲍曼不动杆菌耐药谱;同时利用IRS-PCR对此73株鲍曼不动杆菌进行基因分型;并分析IRS-PCR分型与鲍曼不动耐药谱的关系;结合IRS-PCR分型结果与73株鲍曼不动杆菌感染病例的临床资料,分析在此时间段鲍曼不动杆菌在我院流行感染的情况.结果 药物敏感试验将73株鲍曼不动杆菌菌株分为A1(19株全耐药型)和A2 ～ A31(54株耐药谱型)31个药敏谱.IRS-PCR法将其分为A～W共23个基因型,其中A、C、B、D和E型为5种优势菌株,分别为14、11、10、8和6株.对比研究发现A1型菌株(15/19)主要集中在基因型A、C、D内,而基因型B包含A15型耐药菌株9株(69.2％),基因型E包含A3型耐药菌株3株(42.9％).A基因型在院内特别是ICU中心引起2次爆发流行,而C和D型主要在呼吸内科引起感染.结论 IRS-PCR基因分型与药敏分型有较高的一致性,且IRS-PCR基因分型在早期发现和预防感染暴发流行方面优于药敏分型.     

鲍曼不动杆菌对碳青霉烯类抗生素的耐药性分析

目的了解鲍曼不动杆菌的耐药情况,并检测耐碳青霉烯类鲍曼不动杆菌的耐药基因,为指导临床合理用药、控制院内感染提供依据。方法利用K-B法检测45株鲍曼不动杆菌临床分离株的耐药情况,通过改良Hodge试验、Carba NP试验和EDTA协同试验对多重耐药鲍曼不动杆菌的碳青霉烯酶进行表型检测,并采用PCR技术检测鲍曼不动杆菌携带OXA-23和NDM-1型耐药基因的情况。结果 45株鲍曼不动杆菌临床分离株中共筛出42株多重耐药菌株;利用改良Hodge试验和Carba NP试验检出36株碳青霉烯酶阳性菌株;采用PCR扩增出OXA-23,未扩增出NDM-1。结论鲍曼不动杆菌耐药情况严重,且耐药基因OXA-23携带率高,治疗时应根据药敏试验结果合理用药。     

临床分离鲍曼不动杆菌的外排泵基因检测及同源性分析

目的探讨临床分离鲍曼不动杆菌主动外排基因的分布和菌株克隆相关性,为指导临床合理用药和制定恰当的感染控制措施提供理论依据。方法对临床分离的80株鲍曼不动杆菌采用琼脂稀释法检测对抗菌药物的敏感性,聚合酶链反应(PCR)检测adeB、adeG、adeJ外排泵基因的携带情况,脉冲场凝胶电泳法分析多重耐药鲍曼不动杆菌的同源性。结果 80株临床分离鲍曼不动杆菌中,57株为多重耐药株(MDRAB),且对多粘菌素B、头孢哌酮/舒巴坦和美罗培南较为敏感,对其他临床常用抗生素普遍耐药。adeB、adeG、adeJ外排泵基因分布广泛,在敏感菌株中存在率也很高;PFGE分型结果显示57株MDRAB菌株共分为四大群(A、B、C、D),并以流行克隆A为主。结论临床分离鲍曼不动杆菌耐药形式严峻,其临床分离株普遍存在外排泵编码基因adeB、adeG、adeJ,携带外排泵阳性MDRAB菌株的克隆播散是温州地区鲍曼不动杆菌发生耐药的机制之一。     

重症监护病房呼吸机相关性肺炎中鲍曼不动杆菌耐药性的动态分析

目的探讨重症监护病房呼吸机相关性肺炎(VAP)中鲍曼不动杆菌(Acinetobacter baumannii,Ab)的分布特点和耐药性,为临床防治鲍曼不动杆菌感染提供依据。方法对机械通气>48 h的79例患者的气管抽吸物(ETA)进行细菌定量培养和药敏测定。结果回顾性分析79例VAP患者ETA培养出病原菌214株,其中鲍曼不动杆菌79株(36.9%)。鲍曼不动杆菌对常见抗菌药物的耐药率呈上升趋势,出现较多多重耐药和泛耐药菌株。头孢哌酮/舒巴坦和亚胺培南的耐药率分别是55.6%和68.4%,均呈上升趋势。结论鲍曼不动杆菌是VAP常见病原菌之一,鲍曼不动杆菌的耐药性呈上升趋势,特别是多重耐药和泛耐药菌株,应引起高度重视。     

多重耐药鲍曼不动杆菌氨基糖苷类修饰酶与16S rRNA甲基化酶基因的研究

了解氨基糖苷类修饰酶、16S rRNA甲基化酶基因在多重耐药鲍曼不动杆菌中的流行情况。收集2014年12月至2015年3月厦门大学附属成功医院住院患者临床分离的多重耐药鲍曼不动杆菌共28株,采用VIKET Compact 2全自动细菌鉴定系统进行细菌鉴定,应用纸片扩散法(K-B法)检测鲍曼不动杆菌对抗菌药物的耐药性,采用聚合酶链反应(PCR)法检测氨基糖苷类修饰酶、16S rRNA甲基化酶基因。结果显示,多重耐药鲍曼不动杆菌除对头孢哌酮/舒巴坦耐药率为21.4%外,对其他所测药物耐药率均50%,本组28株多重耐药鲍曼不动杆菌共检出5种氨基糖苷类修饰酶基因aac(3)-Ⅰ、aac(3)-Ⅱ、aac(6')-Ⅰb、ant(3")-Ⅰ、aph(3')-Ⅰ和1种16S rRNA甲基化酶基因arm A,阳性率分别为85.7%(24株)、7.14%(2株)、67.8%(19株)、92.9%(26株)、53.6%(15株)和82.1%(23株)。氨基糖苷类修饰酶、16S rRNA甲基化酶耐药基因是多重耐药鲍曼不动杆菌对氨基糖苷类耐药的重要原因。     

2002-2004年鲍曼不动杆菌临床感染分布和耐药性分析

目的了解白求恩国际和平医院临床分离的鲍曼不动杆菌临床感染分布和耐药现状。方法收集2002年1月至2004年12月白求恩国际和平医院鲍曼不动杆菌临床分离株,采用Kirby-Bauer法对19种抗菌药物进行药敏试验;用WHONET5分析试验结果;分析感染患者基础疾病特征。结果3年间共分离鲍曼不动杆菌267株．96．25％分离自住院患者。3．75％分离自门诊患者。该菌对亚胺培南高度敏感,对其他药物呈多重耐药。多重耐药菌株在逐年上升。它主要引起住院老年人和严重外伤患者的下呼吸道感染。结论鲍曼不动杆菌耐药性有逐年上升趋势。     

Building a better neonatal mouse model to understand infant respiratory syncytial virus disease

Background

Respiratory syncytial virus (RSV) is the number one cause of lower respiratory tract infection in infants; and severe RSV infection in infants is associated with asthma development. Today, there are still no vaccines or specific antiviral therapies against RSV. The mechanisms of RSV pathogenesis in infants remain elusive. This is partly due to the fact that the largely-used mouse model is semi-permissive for RSV. The present study sought to determine if a better neonatal mouse model of RSV infection could be obtained using a chimeric virus in which the F protein of A2 strain was replaced with the F protein from the line 19 clinical isolate (rA2-19F).

Methods

Five-day-old pups were infected with the standard laboratory strain A2 or rA2-19F and various immunological and pathophysiological parameters were measured at different time points post infection, including lung histology, bronchoalveolar lavage fluid (BALF) cellularity and cytokines, pulmonary T cell profile, and lung viral load. A cohort of infected neonates were allowed to mature to adulthood and reinfected. Pulmonary function, BALF cellularity and cytokines, and T cell profiles were measured at 6 days post reinfection.

Results

The rA2-19F strain in neonatal mice caused substantial lung pathology including interstitial inflammation and airway mucus production, while A2 caused minimal inflammation and mucus production. Pulmonary inflammation was characterized by enhanced Th2 and reduced Th1 and effector CD8⁺ T cells compared to A2. As with primary infection, reinfection with rA2-19F induced similar but exaggerated Th2 and reduced Th1 and effector CD8⁺ T cell responses. These immune responses were associated with increased airway hyperreactivity, mucus hyperproduction and eosinophilia that was greater than that observed with A2 reinfection. Pulmonary viral load during primary infection was higher with rA2-19F than A2.

Conclusions

Therefore, rA2-19F caused enhanced lung pathology and Th2 and reduced effector CD8⁺ T cell responses compared to A2 during initial infection in neonatal mice and these responses were exacerbated upon reinfection. The exact mechanism is unknown but appears to be associated with increased pulmonary viral load in rA2-19F vs. A2 infected neonatal lungs. The rA2-19F strain represents a better neonatal mouse model of RSV infection.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-015-0244-0) contains supplementary material, which is available to authorized users.     

Pneumocystis carinii infection sensitizes lung to radiation-induced injury after syngeneic marrow transplantation: role of CD4+ T cells

A murine model of bone marrow transplant (BMT)-related lung injury was developed to study how infection sensitizes lung to the damaging effects of total body irradiation (TBI) at infectious and TBI doses that individually do not cause injury. Mice infected with Pneumocystis carinii exhibited an asymptomatic, rapid, and transient influx of eosinophils and T cells in bronchoalveolar lavage fluid (BALF). In contrast, mice infected with P. carinii 7 days before receiving TBI and syngeneic BMT (P. carinii/TBI mice) exhibited severe pulmonary dysfunction, surfactant aggregate depletion, and surfactant activity reductions at 17 days post-BMT. BALF from P. carinii/TBI mice contained a disproportionate initial influx of CD4(+) T cells (CD4(+):CD8(+) ratio of 2.7) that correlated with progressive lung injury (from 8 to 17 days post-BMT). Levels of TNF-alpha in BALF were significantly increased in P. carinii/TBI mice compared with mice given either insult alone, with peak values found at 11 days post-BMT. In vivo depletion of CD4(+) T cells in P. carinii/TBI mice abrogated pulmonary dysfunction and reduced TNF-alpha levels in BALF, whereas depletion of CD8(+) T cells did not affect lung compliance or TNF-alpha. Lung injury was not attributable to direct P. carinii damage, since CD4-depleted P. carinii/TBI mice that exhibited no injury had higher average lung P. carinii burdens than either mice given P. carinii alone or undepleted P. carinii/TBI mice. Together, these results indicate that P. carinii infection can sensitize the lung to subsequent TBI-mediated lung injury via a process dependent on non-alloreactive CD4(+) T cells.     

禽流感H5N1亚型病毒对五个不同品系小鼠致病性的比较(英文)

目的比较了不同遗传背景小鼠对禽流感H5N1亚型病毒的致病敏感性,为H5N1禽流感模型制作和机理研究提供依据。方法近交系BALB/c、C57BL/6和封闭群ICR、NIHSwiss和KMSwiss共五个不同品系小鼠。每个品系实验动物30只,分接毒组20只,空白对照组10只,每组雌雄各半。病毒株为A/Goose/Guangdong/NH/2003(H5N1),经测定TCID50为10-4.875/mL。接毒组通过鼻腔接种0.1mL病毒液,对照组接种正常鸡胚尿囊液。小鼠接毒后连续观察14d,观察记录临床症状、体温、体重变化,对在实验期间死亡和实验14d结束后仍然存活的小鼠均进行组织器官病理取材,进行RT-PCR病毒分离检测、HE染色及H5N1抗原特异性免疫组化染色。结果①临床症状:H5N1禽流感病毒能感染五个品系的小鼠,引起呼吸急促等症状和一过性体重、体温下降。②死亡情况:小鼠在接毒后第1天即出现死亡,死亡的高峰期集中在接毒后第3～6天。五个品系小鼠死亡率存在差异,BALB/c为70%,ICR为50%,NIHSwiss为40%,C57BL/6为25%,KMSwiss为10%;③病毒分离:各组接毒小鼠在死亡后均进行了病毒分离,死亡小鼠的肺脏均分离到病毒,其他脏器未分离到病毒。④病理变化:实验期间五个品系死亡小鼠肺脏病理改变相近。大体观:死亡小鼠肺部淤血,呈暗红色,体积增大,局部肺组织实变。镜下观:死亡小鼠的共同病理改变为间质性肺炎,具体表现为肺泡腔及间质出血、炎性细胞浸润;间质增生,肺泡隔增宽;肺泡腔中见纤维素性渗出,透明膜形成。⑤免疫组化结果 :在死亡小鼠的气管上皮细胞和肺巨噬细胞可观察到H5N1禽流感病毒阳性表达。结论小鼠作为H5N1禽流感病毒模型具有普适性,不同品系小鼠感染鹅源H5N1禽流感病毒的临床症状、病程和病理变化与人禽流感病例相似。不同品系小鼠的死亡比例有明显差别,可以根据不同的实验目的 ,选择不同品系的小鼠制作H5N1禽流感动物模型。不同品系的遗传特性对禽流感易感性产生明显的影响,遗传背景可能与H5N1禽流感病毒感染应答机理存在联系:BALB/c和C57BL/6均为近交系,其中BALB/c小鼠的品系特征之一表现为干扰素产量低,接种H5N1病毒后表现为高死亡率(70%),而C57BL/6小鼠的干扰素产量高,接种H5N1病毒后表现为低死亡率(25%),提示不同遗传背景小鼠的干扰素水平与H5N1感染致死具相关性。为进一步研究H5N1禽流感病毒易感性相关基因以及其与宿主免疫反应的关系提供了一个研究基础。     

小檗碱改善流感病毒性肺炎小鼠肺血管通透性的作用及机制

目的:观察小檗碱对流感病毒感染所致病毒性肺炎小鼠肺血管通透性的影响,并探讨其作用机制。方法:BALB/c小鼠108只随机分为3组,正常组、模型组、小檗碱组,25μL 50LD50病毒液滴鼻建立流感病毒感染的小鼠肺炎模型,感染后1 h,正常组和模型组予以双蒸水灌胃,小檗碱组予药物0.005 g.kg-1d-1腹腔注射;各组均给药2次/d,连续给药5 d。感染后的2 d、4 d、6 d,处死小鼠,肺组织称重以检测肺含水量;1%伊文氏兰5 mL/kg尾静脉注射检测肺血管通透性;Bicinchoninic acid(BCA)法检测肺泡灌洗液(BALF)中蛋白含量;放免法或酶免法测定肺组织中PGE2、PLA2及LT-B4含量。结果:病毒感染后,模型组肺含水量持续升高,肺血管通透性及BALF蛋白含量在感染后第4天开始明显升高,小檗碱降低了肺含水量、肺血管通透性及BALF蛋白含量(P<0.01);模型组肺组织中PGE2、PLA2、LT-B4的含量明显升高,小檗碱不同程度地抑制了PGE2、PLA2、LT-B4的表达。结论:小檗碱通过抑制流感病毒感染后肺组织中PGE2、PLA2、LT-B4的释放,降低了肺血管通透性及肺含水量,对病毒性肺炎中肺水肿的形成,起到一定的治疗作用。     

Bacillus thuringiensis serotype H34 isolated from human and insecticidal strains serotypes 3a3b and H14 can lead to death of immunocompetent mice after pulmonary infection

In 1995, we isolated a strain of Bacillus thuringiensis serotype H34 from severe human tissue necrosis. This bacterium was able to induce myonecrosis in immunosuppressed mice after cutaneous infection. Its potential pathogenicity for immunocompetent hosts was investigated in a mouse model of pulmonary infection. Mice infected intranasally by a suspension containing 10(8) spores died within 8 h in a clinical toxic-shock syndrome. In the same conditions, infection with a mutant without crystalline toxin, with the supernatant from a culture containing 10(8) bacteria ml(-1) and by the insecticidal strain serotypes 3a3b or H14 led to identical results. Lower inocula simply induced a local inflammatory reaction with bacterial persistence observed during the course of 10 days.     

Lipoolygosaccharide indirectly enhances inflammatory lesions in lungs as a primary infection site by non-encapsulated and type B Haemophilus influenzae through production of cytokines

We investigated the role of cytokines in differences in histopathologic changes in the lung between bronchopneumonia caused by non-encapsulated Haemophilus influenzae strain 770235f(0)b(0)and systemic disease caused by type b H. influenzae strain 770235f(0)b(+). Tumour necrosis factor-alpha (TNF-alpha), interleukin-(IL)-6 and IL-1 beta levels in bronchoalveolar lavage fluid (BALF) samples of mice infected with strain 770235f(0)b(0)were higher than in those infected with strain 770235f(0)b(+)until 24 h post-infection. Serum IL-6 rapidly increased in strain 770235f(0)b(0)infection after 72 h post-infection. Serum TNF-alpha level in strain 770235f(0)b(0)infection appeared earlier than in strain 770235f(0)b(+)infection. IL-1 beta production in strain 770235f(0)b(+)infection was later than in strain 770235f(0)b(0)infection. Moreover, a biphasic concentration pattern of TNF-alpha and IL-6 was noted in BALF of mice with strain 770235f(0)b(0)infection.     

貂源绿脓杆菌的分离鉴定及其致病性

为了揭示绿脓杆菌对水貂的致病性,本研究采用细菌分离培养方法、形态学观察、生化试验、药敏试验与16S rDNA测序等技术,对2013年在山东省诸城、文登与临沂采集的43份发病水貂肺组织进行了细菌分离鉴定。结果分离到的5株细菌均为绿脓杆菌（分别命名为F1、F5、F6、F8、F10）,分离率为11.6%。所分离的5株绿脓杆菌之间的核酸同源性为 98.9 %～99.7 %; F5、F6、F8、F10与F1在一个大的分支上。用F1株对小鼠与水貂分别进行接种攻毒,建立绿脓杆菌对小鼠与水貂的致病性研究动物模型。F1在小鼠肺部含量较高,半数致死量（LD₅₀）为 1.6×10⁶CFU/mL,对小鼠有较强的致病力;F1对水貂的LD₅₀为3.2×10⁷CFU/mL,接种3.2×10⁸CFU/mL菌液的水貂在接种后的20-44h内全部死亡,其他感染组的水貂仅表现一过性的精神不振、食欲稍有下降,这表明绿脓杆菌对水貂具有一定的致病力。     

Multidrug-resistant genes are associated with an 86-kb island in Acinetobacter baumannii

A strain of multidrug-resistant Acinetobacter baumannii that caused a 26% mortality rate in a French epidemic was characterized and compared with an antibiotic-susceptible strain of A. baumannii. The multiresistant strain carries many of its antibiotic-resistance genes on an 86-kb region, whereas the susceptible strain lacks these genes in a homologous region. Characterization of this multidrug-resistant A. baumannii strain highlights the limited options for current therapy and raises concerns for future treatment options in an era in which few novel antibiotics are being developed.     

Therapeutic effect of anti-macrophage inflammatory protein 2 antibody on influenza virus-induced pneumonia in mice

We investigated the effect of anti-macrophage inflammatory protein 2 immunoglobulin G (aMIP-2 IgG) on the progression of influenza virus-induced pneumonia in mice. When mice were infected with a mouse lung-adapted strain of influenza A/PR/8/34 virus by intranasal inoculation, neutrophil counts in the bronchoalveolar lavage fluid (BALF) increased in parallel with the kinetics of MIP-2 production, which peaked 2 days after infection. After intracutaneous injection of a dose of 10 or 100 microg of aMIP-2 IgG once a day on days 0 and 1, neutrophil counts in BALF on day 2 were reduced to 49 or 37%, respectively, of the value in the control infected mice administered anti-protein A IgG. The antibody administration also improved lung pathology without affecting virus replication. Furthermore, by prolonged administration with a higher or lower dose for up to 5 days, body weight loss became slower and finally 40% of mice in both treatment groups survived potentially lethal pneumonia. These findings suggest that MIP-2-mediated neutrophil infiltration during the early phase of infection might play an important role in lung pathology. Thus, MIP-2 was considered to be a novel target for intervention therapy in potentially lethal influenza virus pneumonia in mice.