广州地区老年人肺炎链球菌临床分离株的青霉素耐药研究与分子分型

目的调查广州地区老年患者肺炎链球菌分离株对青霉素的敏感性，并分析其亲缘关系。方法K—B纸片法对33株分离自老年住院病人的肺炎链球菌进行青霉素药敏试验；应用PCR技术检测青霉素结合蛋白基因pbp1a，pbp2x，pbp2b；用盒式PCR（BOX—PCR）分析菌株间亲缘关系。用多位点测序分型技术（multilocus sequence typing，MLST）检测青霉素耐药菌株的分子分型。结果青霉素的耐药率为3．03％（1／33）：用PCR方法鉴定PSSP的准确率为68．75％；BOX-PCR可将这33株肺炎链球菌分为21型。MIST分型显示，青霉素耐药菌株属ST271型。结论广州地区老年患者肺炎链球菌对青霉素耐药率较低．用PCR方法检测PSSP有一定的可行性。BOX—PCR显示了较高的分辨率，能快速可靠地检测菌株间的亲缘关系。广州地区流行的耐药克隆与Taiwan^19F-14株同源。     

murM基因变异与肺炎链球菌青霉素高度耐药及头孢曲松耐药的相关性

目的　研究肺炎链球菌murM基因变异与青霉素及头孢曲松耐药的相关性。方法　应用PCR技术扩增肺炎链球菌murM基因并进行基因测序。选取肺炎链球菌株 5 5株 ,包括青霉素敏感株 10株 (MIC≤ 0 .0 6 μg/ml) ;青霉素耐药株 4 5株 ,其中低水平耐药 10株 (MIC 0 .12～ 1μg /ml) ,高水平耐药 35株 (MIC≥ 2 μg/ml) ,在青霉素高水平耐药菌株中 ,对头孢曲松耐药 13株 (MIC≥ 2 μg/ml)。用敏感株R36AmurM基因序列作为比较标准。结果　 5 5株肺炎链球菌murM基因PCR产物测序结果 ,16株murM基因发生显著变异 (变异率≥ 3% ) ,1株青霉素MIC 3μg/ml、头孢曲松MIC 2 μg/ml的菌株 ,其murM基因变异率 3.4 % ;15株青霉素MIC≥ 8μg/ml或头孢曲松MIC≥ 2 μg/ml的菌株 ,murM基因变异率达 10 % ,呈嵌合式变异。murM基因变异与肺炎链球菌青霉素及头孢曲松MIC显著相关 (χ2 =36 .5 32 ,P <0 .0 1;χ2 =37.116 ,P <0 .0 1)。结论　肺炎链球菌murM基因变异与青霉素高度耐药 (MIC≥8μg/ml)及头孢曲松耐药 (MIC≥ 2 μg/ml)有显著的相关性。     

黏液型肺炎链球菌的表型和遗传学特征

目的了解儿童临床标本中分离的黏液型肺炎链球菌的表型和遗传学特点。方法用奥普托欣试验、乳胶凝集试验和菊糖发酵试验鉴定肺炎链球菌,用纸片扩散法(KirbyBauer法)和Etest法完成菌株的药敏试验,用BOXPCR技术和青霉素结合蛋白基因PCR扩增及限制性内切酶消化分析菌株的遗传学特点。结果分离到黏液型肺炎链球菌5株,占同期肺炎链球菌临床株的2.1%。5株菌株均对青霉素、氨苄西林、头孢噻肟、甲氧苄啶磺胺异唑、红霉素、氯霉素、利福平、氧氟沙星和万古霉素敏感,仅3株对四环素中介。5株菌株的BOX图谱各不相同,其中1例同时分离到黏液型和非黏液型菌落,两者具有相同的BOX图谱。5株黏液型菌株3种青霉素结合蛋白基因指纹图谱均彼此相同。结论黏液型肺炎链球菌在儿科临床不常见,且对常用抗生素往往敏感,5株黏液型菌株系不同的克隆。     

上颌窦炎及咽炎患者肺炎链球菌带菌及耐药性调查

目的 调查急慢性上颌窦炎及咽炎患者肺炎链球菌带菌及耐药情况。方法 用E—test法及纸片扩散法测定耐药情况．结果 86株肺炎链球菌中，对青霉素敏感64株(74.4％)，低度耐药18株(20．9％)，高度耐药4株(4．7％)，青霉素耐药菌株对红霉索、氯霉素、复方新诺明及四环素的耐药率比青霉素敏感株高，所有菌株对万古霉素敏感．结论 了解细菌耐药性的变化是合理应用抗生素的重要依据。     

肺炎链球菌青霉素结合蛋白基因pbp2x新的变异与青霉素及头孢噻肟耐药

目的 调查研究肺炎链球菌临床分离株的pbp2x基因和氨基酸序列的变异特点,探讨本地区的肺炎链球菌对青霉素及头孢噻肟的耐药机制.方法 2006年1月-2007年2月收集肺炎链球菌临床分离株34株,进行青霉素及头孢噻肟药敏试验,对青霉素不敏感的肺炎链球菌(PNSP)的青霉素结合蛋白pbp2x基因进行PCR扩增和测序,并进行BLAST分析.结果 有12株PNSP(青霉素及头孢噻肟MIC≥0.5 mg/L)发生了2个重要位点的氨基酸的替换:第一个保守基序STMK内Thr338→Ala及第三个保守基序KSG之前的Leu546→Val氨基酸替换.另外,菌株15发生了第二个保守基序SSN之前的His394→Leu氨基酸替换,而且本研究首次发现了紧邻第一个保守基序STMK后,Met342→Ile位点的氨基酸替换.有17个菌株的pbp2x基因的核苷酸及氨基酸序列出现了新的变异,已向GenBank提交,获得序列号:EU044831、EU089706-EU089709、EU106881-EU106884、EU124672.结论 本地区大多数PNSP的pbp2x核苷酸及氨基酸变异序列高度相似,提示肺炎链球菌对青霉素及头孢噻肟的耐药与pbp2x基因变异相关.     

79株肺炎链球菌的耐药性测定

目的调查北京地区肺炎链球菌对青霉素等抗生素的耐药率。方法用Ｅｔｅｓｔ及琼脂稀释法测定临床分离的７９株肺炎链球菌１５种抗生素的最低抑制浓度（ＭＩＣ）。结果Ｅｔｅｓｔ测得１０株（１２．７％）低耐青霉素（ＭＩＣ０．１２５～１μｇ／ｍｌ），１株（１．３％）高耐青霉素（ＭＩＣ４μｇ／ｍｌ）；仅１株处于头孢曲松、头孢噻肟中介范围（ＭＩＣ１μｇ／ｍｌ）．琼脂稀释法测得阿莫西林、阿莫西林／棒酸、头孢呋肟、环丙沙星、氯霉素、四环素、红霉素的耐药率分别为１．３％、１．３％、２．５％、２．５％、１６．５％、４９．４％、４０．５％，所有菌株对头孢曲松、万古霉素敏感。结论北京地区１４％的肺炎链球菌耐青霉素，耐三代头孢菌素及多重耐药株罕见。     

肺炎链球菌pbp2B基因突变与耐药表型关系的研究

肺炎链球菌主要通过青霉素结合蛋白基因突变，从而改变细胞壁上高相对分子质量青霉素结合蛋白（PBP）的结构，降低了其对抗生素分子的亲和性而产生对青霉素等B内酰胺类抗生素的耐药性。我们对分离自本院的30株肺炎链球菌（青霉素敏感4株，中介5株，耐药21株）用聚合酶链反应（PCR）扩增p6p2B基因，对PCR产物直接进行DNA测序，并与青霉素敏感的SpR6株序列（GenBank登录号NC003098）相比较。     

上颌窦炎及咽炎患者肺炎链球菌带菌及耐药性调查

目的调查急慢性上颌窦炎及咽炎患者肺炎链球菌带菌及耐药情况. 方法用E-test法及纸片扩散法测定耐药情况. 结果 86株肺炎链球菌中,对青霉素敏感64株(74.4%),低度耐药18株(20.9%),高度耐药4株(4.7%),青霉素耐药菌株对红霉素、氯霉素、复方新诺明及四环素的耐药率比青霉素敏感株高,所有菌株对万古霉素敏感. 结论了解细菌耐药性的变化是合理应用抗生素的重要依据.     

肺炎链球菌青霉素耐药相关基因研究

目的　了解我国肺炎链球菌 (Streptococcuspneumoniae,Sp)青霉素耐药相关基因的存在与突变状况。方法　设计、优化pbp1a、TEM基因PCR检测体系及扩增产物全自动DNA序列测定体系 ,对 3株分离自苏州地区患儿呼吸道的Sp(青霉素低耐株SR0 17、SR0 19;青霉素敏感株SR0 2 8,3株均苯唑青耐药 ,且SHV基因均为阴性 )进行检测 ,测得的pbp1aDNA序列与SpR6株 (青霉素敏感株 )DNA序列相比较 ;测得的TEM基因DNA序列与同院原分离的产超广谱 β内酰胺酶大肠埃希菌中检出的TEM 1DNA序列及已在GenBank登录的TEM基因序列相比较。结果　SR0 17、SR0 19、SR0 2 8之pbp1a基因均有突变 ,突变率为 2 1%、2 1%、0 .4 %。SR0 19株TEM基因阴性 ,SR0 17和SR0 2 8TEM基因阳性 ,测得DNA序列分别被证实为TEM 12 9和TEM 1,前者且是新型TEM ,作为新发现的菌种耐药基因均已登录美国国立生物信息中心GenBank ,登录号AY4 5 2 6 6 2、AY392 5 31;二者DNA序列与产超广谱 β内酰胺酶大肠埃希菌中检出的TEM高度同源 (99.7%、99.8% )。结论　我国Sp青霉素耐药可能存在产 β内酰胺酶 (获得TEM基因 )和pbp基因突变两种机制 ,TEM耐药质粒可能在不同种菌株间传播。     

广州地区肺炎住院患儿感染肺炎链球菌的血清型分布及耐药性研究

目的了解广州地区肺炎住院的患儿感染肺炎链球菌的耐药性及血清型分布情况。方法用吸痰法采集患儿痰标本进行涂片，革兰氏染色镜检，合格痰标本划线接种血平板，用E-test法检测分离到的肺炎链球菌对青霉素、阿莫西林、头孢曲松、头孢呋辛、亚胺培南、氧氟沙星、万古霉素、红霉素和克林霉素9种药物的耐药性，采用K-B法检测四环素、复方新诺明的耐药性，并采用荚膜肿胀技术对分离到的79株肺炎链球菌进行血清分型。结果79株肺炎链球菌中青霉素耐药肺炎链球菌（PRSP）11．4％，青霉素中介肺炎链球菌（PISP）77．2％，青霉素敏感肺炎链球菌（PSSP）11．4％，对红霉素、克林霉素的耐药率分别为100％和93．7％，对阿莫西林、氧氟沙星、万古霉素的耐药率均为0，对头孢曲松、头孢呋辛、亚胺培南的耐药率分别为3．8％、72．2％、2．5％。79株肺炎链球菌中只有1株PSSP仅对红霉素耐药．78株肺炎链球菌对两种以上药物耐药．多重耐药率为98．7％（78／79），同时对克林霉素、红霉素、四环素、复方新诺明耐药的菌株65株，占82．3％（65／79）。79株肺炎链球菌血清型分别为19F（70．9％），23F（16．5％），6B（5．1％），4（2．5％），15B（2．5％），不能分型（2．5％），7价疫苗涵盖率为94．9％（75／79）。结论广州地区肺炎住院患儿肺炎链球菌对大环内脂类抗生素红霉素和林可酰胺类抗生素克林霉素耐药情况严重，对二代头孢菌素头孢呋辛耐药率居高，临床治疗儿童肺炎链球菌感染的肺炎应首选阿莫西林和三代头孢菌素。7价疫苗覆盖率高。预防儿童肺炎链球菌感染所致的肺炎，采用7价疫苗可以达到很好效果。     

氯吡格雷抵抗

氯吡格雷抵抗是临床上广泛使用的一个词汇,用来描述服用氯吡格雷而不能提供充分抗血小板作用的一种现象。氯吡格雷抵抗的存在促进了血栓事件的反复发生,在亚急性支架内血栓的形成中也发挥了主要作用。氯吡格雷抵抗分为生物化学抵抗和临床抵抗二种,受多方面因素的影响,包括外部因素和内部因素。但是抵抗的确切原因尚未完全阐明。本文讨论了目前有关氯吡格雷抵抗的证据,以期提供一全面的认识。     

Variable resistance training promotes greater fatigue resistance but not hypertrophy versus constant resistance training

Loading using variable resistance devices, where the external resistance changes in line with the force:angle relationship, has been shown to cause greater acute neuromuscular fatigue and larger serum hormone responses. This may indicate a greater potential for adaptation during long-term training. Twelve (constant resistance group) and 11 (variable resistance group) men completed 20 weeks of resistance training with 10 men as non-training controls. Training-induced adaptations were assessed by bilateral leg press one repetition maximum, a repetition to failure test using 75 % 1RM, lower limb lean mass and vastus lateralis cross-sectional area. Only the variable resistance training group improved the total number of repetitions (41 ± 46 %) and volume load (52 ± 37 %) during the repetition to failure test (P < 0.05). Similar improvements in maximum strength and hypertrophy of the lower limbs were observed in both training groups. Also, constant and variable resistance 5 × 10RM leg press loadings were performed before and after training in a crossover design. Acute loading-induced responses were assessed by concentric and isometric force, serum hormone concentrations and phosphorylation of intramuscular signalling proteins (0–30 min post-loading). Greater acute decreases in force (P < 0.05–0.01), and greater increases in serum testosterone and cortisol concentration (P < 0.05) and ERK 1/2 phosphorylation (P < 0.05) were observed following variable resistance loadings before and after training. Greater training-induced improvements in fatigue resistance occurred in the variable resistance training group, which may be due to greater acute fatigue and physiological responses during variable versus constant resistance loadings.     

Diuretic resistance

Resistance to diuretic action is frequently encountered in the clinical setting. This is best managed by systematically optimizing the pharmacodynamic-pharmacokinetic factors that may be involved. Important pharmacodynamic measures include improving the underlying disease state, restriction of salt intake, limiting the use of vasodilators which may cause hypotension, lowering protein excretion, and eliminating drugs which may modify the response to the diuretic. Pharmacokinetic measures include using doses which result in diuretic excretion rates which fall on the steep part of the dose-response curve, sustaining diuretic excretion in this range by frequent drug administration, or constant infusion, using more bioavailable drugs and drugs which have less hepatic elimination, and by increasing the diuretic concentration in blood by coadministration with albumin. Using diuretic combinations to systematically inhibit absorption in the proximal tubule, Henle's loop, distal convoluted tubule, and connecting/collecting tubule will usually effect diuresis in all but the most refractory of cases.     

Variable resistance versus constant resistance strength training in adult males

Summary Intramuscular triglycerides mobilization during prolonged physical exercise was examined in rats fed ad libitum, in rats fasted for 24 h and in rats treated with nicotinic acid. It has been found that during exercise the intramuscular triglyceride level was markedly reduced only in the red muscle but not in the white and intermediate muscles. Fasting significantly augmented the utilization of triglycerides in the red muscle during exercise. The post-exercise triglyceride level in the red muscle of the rats treated with nicotinic acid was similar to that in the control group whereas blood FFA level, in the nicotinic acid-treated group was much lower than in the control group. Nicotinic acid increased glycogen utilization in the liver and in the skeletal muscles during exercise.It may be concluded that the major cause of the reduction of the triglyceride level in the red muscle during exercise is a developing shortage of available carbohydrates. The greatly elevated blood FFA level during exercise does not seem to have a sparing effect on the intramuscular triglyceride level during exercise. However, it does spare glycogen content in the liver and the skeletal muscles.This work was supported by the Polish Academy of Sciences. project 10.4.2.01.3.2     

Computer-controlled flow resistance

A computer-controlled flow resistance (CCR), to be used in a computer-controlled lung model, is presented. Flow is forced through a slit between a cylinder and a sleeve around the cylinder. The resulting flow resistance depends on the width, circumferences and the variable length of the slit. The variation in the length is computer-controlled by the position of the sleeve with respect to the cylinder. The total flow resistance also depends on inlet and outlet resistance at both sides of the slit and on flow. The dependence on flow is primarily due to the shape of the inlet of the slit. The resistance of the slit itself is almost independent of flow. The resistance is calculated during a calibration phase at different positions of the sleeve, for flow values from 0.05 to 1.0 litre.s-1 (inflow) and from -0.05 to -1.0 litre.s-1 (outflow). To simulate a required resistance pattern, as, for instance, will occur during breathing, at each moment the set position of the sleeve is calculated by means of an interpolation from the relationship between flow resistance and position of the sleeve. The internal diameter of the sleeve is fixed. To tune the resistance range for a specific simulation, the cylinder is changed for one with different diameter, changing the width of the slit.