微生物學(xué)課件：厭氧性細(xì)菌Anaerobic bacteria

2015/5/16AnaerobicBacteria-Junqi'sLecture1厭氧性細(xì)菌Anaerobicbacteria產(chǎn)芽胞厭氧菌致病菌引起外源性感染無芽胞厭氧菌條件致病菌引起內(nèi)源性感染2015/5/16AnaerobicBacteria-Junqi'sLecture2厭氧芽胞梭菌屬（Clostridium）大多為嚴(yán)格厭氧菌，G＋。芽胞直徑比菌體粗，使菌體膨大呈梭狀，對(duì)熱、干燥和消毒劑均有強(qiáng)大的抵抗力。

除產(chǎn)氣莢膜梭菌等極少數(shù)例外，均有周鞭毛，無莢膜。2015/5/16AnaerobicBacteria-Junqi'sLecture3產(chǎn)芽胞厭氧菌所致疾病

破傷風(fēng)梭菌破傷風(fēng)產(chǎn)氣莢膜梭菌氣性壞疽食物中毒壞死性腸炎肉毒梭菌食物中毒艱難梭菌假膜性腸炎2015/5/16AnaerobicBacteria-Junqi'sLecture4破傷風(fēng)梭菌（C.tetani）破傷風(fēng)（tetanus）的病原菌。發(fā)病后機(jī)體呈強(qiáng)直性痙攣、抽搐，可因窒息或呼吸衰竭死亡。2015/5/16AnaerobicBacteria-Junqi'sLecture5

全世界每年大約100萬人死于破傷風(fēng)病。發(fā)展中國家嬰幼兒死亡率高達(dá)85%。破傷風(fēng)是造成兒童死亡的第二大疾病，僅次于麻疹。1949年前，我國嬰兒死亡率達(dá)20%，其中破傷風(fēng)死亡率為50%，是新生兒死亡的第1、2位病因。雖有免疫接種，發(fā)病率有所下降，但全世界嬰兒和成人破傷風(fēng)患病仍占18/10萬人。2015/5/16AnaerobicBacteria-Junqi'sLecture62015/5/16AnaerobicBacteria-Junqi'sLecture7（一）形態(tài)與染色革蘭陽性菌有芽胞芽胞正圓，位于菌體頂端，使細(xì)菌呈鼓槌狀，抵抗力強(qiáng)有鞭毛根據(jù)鞭毛和菌毛抗原可分為10個(gè)血清型，但產(chǎn)生的毒素?zé)o差異（二）培養(yǎng)特性和生化反應(yīng)

嚴(yán)格厭氧

血平板上，有β溶血

不發(fā)酵糖類，不分解蛋白質(zhì)生物學(xué)性狀2015/5/16AnaerobicBacteria-Junqi'sLecture8致病性與免疫性病例討論

男：54歲，農(nóng)民，入院前五天撒豬糞時(shí)不慎，左手掌被竹簽刺入，當(dāng)時(shí)無特殊處理，傷口表面慢慢結(jié)痂，但稍有腫脹三天后患者自覺乏力，張口進(jìn)食有些阻力，頭頸活動(dòng)稍受限制。當(dāng)?shù)匦l(wèi)生員以落枕處理，給予針灸治療，以后逐漸出現(xiàn)全身肌肉間隙性抽動(dòng)，不久發(fā)展不能張口，頭頸向后強(qiáng)直，四肢強(qiáng)直性抽搐，聲音光線刺激都可加重癥狀，立即送醫(yī)院診治，醫(yī)生通過詢問病史及體格檢查，確定診斷，立即搶救治療。2015/5/16AnaerobicBacteria-Junqi'sLecture9思考題：1.小小一根竹簽刺入皮膚，怎么會(huì)引起破傷風(fēng)？2.醫(yī)生根據(jù)什么立即診斷為破傷風(fēng)？3.根據(jù)微生物學(xué)知識(shí)應(yīng)該如何治療病人？4.如何防止上述病例中患者不患這一疾??？2015/5/16AnaerobicBacteria-Junqi'sLecture101.小小一根竹簽刺入皮膚，怎么會(huì)引起破傷風(fēng)？(致病機(jī)制)破傷風(fēng)芽胞經(jīng)傷口而入傷口深，盲端，有泥土雜物污染其他雜菌共同感染厭養(yǎng)環(huán)境2015/5/16AnaerobicBacteria-Junqi'sLecture11芽胞出芽形成繁殖體沿神經(jīng)纖維間隙血流淋巴液釋放破傷風(fēng)痙攣毒素2015/5/16AnaerobicBacteria-Junqi'sLecture12阻止抑制性神經(jīng)介質(zhì)釋放（甘氨酸，

-氨基丁酸）引起麻痹性痙攣癥狀脊髓前角運(yùn)動(dòng)神經(jīng)元延髓運(yùn)動(dòng)神經(jīng)元1.苦笑面容2.牙關(guān)緊閉

3.角弓反張4.驚厥2015/5/16AnaerobicBacteria-Junqi'sLecture13破傷風(fēng)痙攣毒素作用機(jī)制2015/5/16AnaerobicBacteria-Junqi'sLecture142015/5/16AnaerobicBacteria-Junqi'sLecture152015/5/16AnaerobicBacteria-Junqi'sLecture162015/5/16AnaerobicBacteria-Junqi'sLecture17致病條件

該菌無侵襲力，僅在局部繁殖，致

病作用完全有賴于病菌所產(chǎn)生的毒素。

傷口需形成厭氧微環(huán)境：傷口窄而

深（如刺傷）、有泥土或異物污染大面

積創(chuàng)傷、燒傷，壞死組織多，局部組織

缺血的同時(shí)有需氧菌或兼性厭氧菌混合

感染的傷口。2015/5/16AnaerobicBacteria-Junqi'sLecture18對(duì)氧敏感的破傷風(fēng)溶血毒素(tetanolysin)質(zhì)粒編碼的破傷風(fēng)痙攣毒素(tetanospasmin)屬神經(jīng)毒，毒性極強(qiáng)（小鼠LD50為0.015

ng，對(duì)人致死量<1

μg）；為蛋白質(zhì)，不耐熱；可被蛋白酶破壞。致病因子分子量約150kDa；B鏈（重鏈）是與神經(jīng)節(jié)苷脂結(jié)合的單位；A鏈（輕鏈）具有毒性作用（鋅內(nèi)肽酶）,輕鏈和重鏈之間由二硫鍵連結(jié)。2015/5/16AnaerobicBacteria-Junqi'sLecture19破傷風(fēng)痙攣毒素作用機(jī)制2015/5/16AnaerobicBacteria-Junqi'sLecture202015/5/16AnaerobicBacteria-Junqi'sLecture21破傷風(fēng)痙攣毒素作用機(jī)制1.與神經(jīng)系統(tǒng)的結(jié)合：毒素對(duì)腦干神經(jīng)和脊髓前角神經(jīng)細(xì)胞有高度親和力,結(jié)合非常牢固，一旦結(jié)合，抗毒素便不能中和毒素。毒素重鏈識(shí)別神經(jīng)肌肉結(jié)點(diǎn)處運(yùn)動(dòng)神經(jīng)元上的受體并與之結(jié)合，促使毒素進(jìn)入細(xì)胞內(nèi)形成小泡。2.內(nèi)在化作用小泡從外周神經(jīng)末稍沿神經(jīng)軸突逆行向上，到達(dá)運(yùn)動(dòng)神經(jīng)元胞體，進(jìn)入傳入神經(jīng)末稍，最終進(jìn)入中樞神經(jīng)系統(tǒng)。2015/5/16AnaerobicBacteria-Junqi'sLecture223.膜的轉(zhuǎn)位通過重鏈N端的介導(dǎo)產(chǎn)生膜的轉(zhuǎn)位，使輕鏈進(jìn)入胞質(zhì)溶膠。4.胞質(zhì)溶膠中作用靶的改變輕鏈發(fā)揮毒性作用，阻止抑制性神經(jīng)介質(zhì)γ-氨基丁酸的釋放，使肌肉活動(dòng)的興奮與抑制失調(diào)，造成強(qiáng)直性痙攣。2015/5/16AnaerobicBacteria-Junqi'sLecture23一般不進(jìn)行涂片、鏡檢和分離培養(yǎng)，典型的癥狀和病史即可作出診斷：病史：患者有開放性損傷感染史，或新生兒臍帶消毒不嚴(yán)，產(chǎn)后感染，外科手術(shù)史。典型的癥狀：牙關(guān)緊閉，苦笑面容，角弓反張，驚厥及其它2.醫(yī)生根據(jù)什么診斷為破傷風(fēng)？（病史及臨床表現(xiàn)）2015/5/16AnaerobicBacteria-Junqi'sLecture243.根據(jù)微生物學(xué)知識(shí)應(yīng)該如何治療病人？免疫性：破傷風(fēng)免疫屬外毒素免疫，主要是抗毒素發(fā)揮中和作用。一般病后不會(huì)獲得牢固免疫力（毒素量極低且與神經(jīng)組織牢固結(jié)合，不能有效刺激免疫系統(tǒng)）獲得有效抗毒素的途徑是人工免疫。2015/5/16AnaerobicBacteria-Junqi'sLecture25正確處理創(chuàng)口及清創(chuàng)、擴(kuò)創(chuàng)?？股?，清除局部細(xì)菌。發(fā)病早期可足量使用抗毒素進(jìn)行特異性治療，盡早足量，10～20萬單位。如為馬血清制品，應(yīng)皮試或脫敏。有人抗破傷風(fēng)免疫球蛋白更好（humantetanusimmunoglobulin,HTIG）。2015/5/16AnaerobicBacteria-Junqi'sLecture264.如何防止上述病例中患者不患這一疾??？預(yù)防：人工自動(dòng)免疫：用類毒素或白百破三聯(lián)疫苗（DPT）：軍人，易受外傷成人，兒童等，第一年注射2次，第二年加強(qiáng)一次，可維持免疫力12年。懷孕前婦女：注射類毒素，降低新生兒破傷風(fēng)發(fā)病率。緊急預(yù)防：

清創(chuàng)；

使用用抗生素；

人工被動(dòng)免疫：以往注射過類毒素基礎(chǔ)免疫者，再注射一針類毒素，無需注射破傷風(fēng)抗毒素（tetanusantitoxin,TAT)；無基礎(chǔ)免疫者清創(chuàng)，注射抗毒素，皮試，TAT1500～3000u，同時(shí)注射另一臂類毒素。2015/5/16AnaerobicBacteria-Junqi'sLecture27產(chǎn)氣莢膜梭菌(C．perfringens)兩端平切G＋粗大桿菌體內(nèi)有明顯的莢膜洶涌發(fā)酵（stormyfermentation）雙層溶血Nagler反應(yīng)陽性根據(jù)所產(chǎn)毒素不同分成A-E五個(gè)血清型1892年,美國病理學(xué)家W.H.韋爾奇等自一尸體分出本菌,因而又稱韋氏梭菌2015/5/16AnaerobicBacteria-Junqi'sLecture28產(chǎn)氣莢膜梭菌主要和次要毒素及其分型2015/5/16AnaerobicBacteria-Junqi'sLecture29Stormyfermentation2015/5/16AnaerobicBacteria-Junqi'sLecture30βetatoxinPore-former,functionssimilarlytoα-toxinεpsilontoxinBindstightlytotheplasmamembraneofsensitivecells-doesnotenterthemembrane.Throughanunknownmechanism,theε-toxinisbelievedtoaffectcellmembranepermeability.

ιotatoxinA-Btoxin-consistsofabindingcomponent(Ib)andanenzymaticprotein(Ia),catalyzestheADP-ribosylationofactinmonomers.thetθtoxinbindscholesterolineukaryoticmembranes,causesthecompletehemolysisofredbloodcellsbyformingoligomerswhichsubsequentlyformporesthroughthecellmembrane.κappatoxincollagenase-canhydrolyzecollagenmolecules-destructionofbloodvesselsandconnectivetissuesobservedinclostridialmyonecrosis.δigmatoxinselectivelylysescells,doesnotenterthecellmembrane,thetoxin’sexactmechanismofdisruptionisnotknown.雙層溶血內(nèi)環(huán)：θ毒素，較窄的透明溶血環(huán)外環(huán)：α毒素，不完全溶血環(huán)2015/5/16AnaerobicBacteria-Junqi'sLecture31Nagler反應(yīng)：α毒素分解卵磷脂2015/5/16AnaerobicBacteria-Junqi'sLecture32

致病物質(zhì)侵襲力強(qiáng)的溶血毒素和酶類

1.卵磷脂酶（α毒素）是氣性壞疽最為重要的毒素；

2.腸毒素可引起食物中毒；

3.C型株產(chǎn)生的β毒素是人類壞死性腸炎的致病物質(zhì)。致病性與免疫性2015/5/16AnaerobicBacteria-Junqi'sLecture33所致疾病氣性壞疽（A型為主）食物中毒（A型）壞死性腸炎（C型為主）2015/5/16AnaerobicBacteria-Junqi'sLecture34參考病例：

男，26歲，工人，在架高壓線時(shí)不慎跌落在工地上，立即送醫(yī)院，檢查下肢股骨、脛骨多處開放性骨折。局部用鹽水洗后復(fù)位包扎固定,同時(shí)取材厭氧培養(yǎng)分離細(xì)菌。一天后患者自覺局部繃帶過緊，疼痛劇烈，要求松開繃帶，一小時(shí)后又要求松繃帶。2015/5/16AnaerobicBacteria-Junqi'sLecture35

第二天體溫達(dá)40℃，神志淡漠，面色蒼白，局部肢體高度水腫，壞死組織呈灰黑色，血性滲出物內(nèi)有氣泡，奇臭、傷口邊緣有捻發(fā)音，根據(jù)癥狀及體征作出診斷后，立即截肢，并用多價(jià)抗毒素和抗生素治療才搶救脫險(xiǎn)。2015/5/16AnaerobicBacteria-Junqi'sLecture36肢體創(chuàng)傷戰(zhàn)傷、工傷、大面積開放性骨折、軟組織損傷等缺血、缺氧組織壞死，產(chǎn)生半胱氨酸、色氨酸刺激芽胞出芽繁殖體2015/5/16AnaerobicBacteria-Junqi'sLecture37釋放酶、毒素（α-毒素）分解肌糖原、血糖、破壞機(jī)體組織產(chǎn)生大量氣體及皮下氣腫加重缺血缺氧，肢體壞死，病變迅速，引起全身中毒癥狀氣性壞疽2015/5/16AnaerobicBacteria-Junqi'sLecture38拍攝時(shí)間：1943年6月21日拍攝地點(diǎn)：加拿大紐芬蘭拍攝者：第21陸軍通信兵FortPepperell照片描述：病人正在接受氣性壞疽病治療。2015/5/16AnaerobicBacteria-Junqi'sLecture39

2008年5月20日，地震災(zāi)區(qū)發(fā)現(xiàn)58例氣性壞疽?。换颊咴诟邏貉跖摾餁⒕?015/5/16AnaerobicBacteria-Junqi'sLecture40臨床表現(xiàn)，如損傷或手術(shù)后，傷口出現(xiàn)不尋常的疼痛，局部腫脹迅速加劇，傷口周圍皮膚有捻發(fā)音，并有嚴(yán)重的全身中毒癥狀，如脈搏加速、煩躁不安進(jìn)行性貧血，即應(yīng)考慮有氣性壞疽的可能；傷口內(nèi)的分泌物涂片檢查有大量革蘭染色陽性粗大桿菌；X線檢查傷口肌群間有氣體。臨床主要診斷依據(jù)主要依據(jù)臨床表現(xiàn)、傷口分泌物檢查和X線檢查，是診斷氣性壞疽的三個(gè)重要依據(jù)。2015/5/16AnaerobicBacteria-Junqi'sLecture41Gasgangrene.A.Armofadrugabuserwithulcersandswellingtracedtoneedletracks.B.Radiographsfromthesamepatientdemonstratinggas(clearspaces)inthetissues.(PathologyofInfectiousDiseases.StamfordCT:Appleton&Lange,1997.)2015/5/16AnaerobicBacteria-Junqi'sLecture42主要針對(duì)氣性壞疽直接涂片染色（診斷價(jià)值極大）：

革蘭陽性大桿菌（無芽胞）伴其他雜菌白細(xì)胞少

分離培養(yǎng)

動(dòng)物試驗(yàn)微生物學(xué)檢查法2015/5/16AnaerobicBacteria-Junqi'sLecture43清創(chuàng)，切除感染壞組織早期多價(jià)抗毒素大劑量青霉素，高壓氧艙防治原則2015/5/16AnaerobicBacteria-Junqi'sLecture44食物中毒（A型菌株引起）食入被本菌污染的食物釋放腸毒素作用于十二指腸影響細(xì)胞膜代謝腹痛、腹瀉稍有惡心，無嘔吐、發(fā)熱2015/5/16AnaerobicBacteria-Junqi'sLecture45壞死性腸炎C型菌株所致，致病物質(zhì)為β毒素。

β毒素可引起腸道運(yùn)動(dòng)神經(jīng)麻痹，進(jìn)而發(fā)生壞死。潛伏期不到24小時(shí)，起病急，有劇烈腹痛、腹瀉、腸粘膜出血性壞死，糞便帶血；可并發(fā)周圍循環(huán)衰竭、腸梗阻、腸穿孔、急性腹膜炎等，病死率高達(dá)40％。此病1946年首先在德國發(fā)現(xiàn)數(shù)百例，以后在新幾內(nèi)亞一帶流行，各國也有散發(fā)病例。

兒童多見，常于節(jié)日進(jìn)食大量被該菌污染烹調(diào)不當(dāng)?shù)呢i肉、牛肉所引起。2015/5/16AnaerobicBacteria-Junqi'sLecture46肉毒梭菌

Clostridiumbotulinum所致疾?。菏澄镏卸?/p>

是唯一不表現(xiàn)消化道癥狀而以神經(jīng)系統(tǒng)癥狀為主的食物中毒。嬰兒肉毒癥（污染的蜂蜜）創(chuàng)傷肉毒癥芽胞呈橢圓形，粗于菌體，位于次極端，使細(xì)胞呈湯匙狀或網(wǎng)球拍狀肉毒梭菌2015/5/16AnaerobicBacteria-Junqi'sLecture47

肉毒毒素：肉毒毒素是世界上最毒物，根據(jù)抗原性不同可分A、B、C1、C2、D、E、F、G共8型。各型毒素只能被同型抗毒素中和。為嗜神經(jīng)毒素：阻止膽堿能神經(jīng)釋放乙酰膽堿，影響神經(jīng)沖動(dòng)的傳遞，導(dǎo)致肌肉麻痹。Alltoxinsareheat-labileanddestroyedrapidlyat100℃(destroyedbyboiling),butareresistanttotheenzymesofthegastrointestinaltract.botulinumtoxin："sausagepoison"and"fattypoison"2015/5/16AnaerobicBacteria-Junqi'sLecture482015/5/16AnaerobicBacteria-Junqi'sLecture492015/5/16AnaerobicBacteria-Junqi'sLecture50實(shí)驗(yàn)室診斷：細(xì)菌分離、毒素檢測（最可靠）防治：加強(qiáng)食品的衛(wèi)生管理和監(jiān)督多價(jià)抗毒素血清治療加強(qiáng)護(hù)理，對(duì)癥治療藥物應(yīng)用：美容、肌張力亢進(jìn)難以治愈性疼痛病2015/5/16AnaerobicBacteria-Junqi'sLecture51美國眼力健(Allergan)公司的BOTOX英國Ipsen公司的Dysport我國的BTXAFirstusedforcrossedeyes,Blepharospasmandstrabismus2015/5/16AnaerobicBacteria-Junqi'sLecture523.治療國字臉

經(jīng)常在同一塊肌肉處重復(fù)注射A型肉毒桿菌毒素,可以導(dǎo)致肌肉產(chǎn)生廢用性萎縮。目前,韓國美容界流行采用A型肉毒桿菌毒素治療國字臉,即將肉毒毒素注射到面部的兩側(cè)咬肌,使肌肉萎縮達(dá)到修飾臉部輪廓的效果。

1.除皺2.調(diào)整眉形2015/5/16AnaerobicBacteria-Junqi'sLecture53采用該方法可以修飾小腿、手臂或大腿前側(cè)肌肉的外形……2015/5/16AnaerobicBacteria-Junqi'sLecture54腸道中正常菌群，可因長期使用抗生素引起的偽膜性腸炎。G＋粗大桿菌，有鞭毛，有芽胞。艱難梭菌（

C．difficile）2015/5/16AnaerobicBacteria-Junqi'sLecture55ColonwithdiscreteplaquesofpseudomembraneHistopathologydemonstratesthepseudomembraneabovethemucosaCDAD(C.difficileassociatedDiarrhrea)Metronidazole（甲硝唑）andvancomycin（萬古霉素）areeffectivetreatmentforpatientssufferingfromCDIwhichcanrangefromdiarrheatopseudomembranouscolitisFecalmicrobiotatransplantation，F(xiàn)MTFMThasbeenusedtotreatotherconditions,includingcolitis,constipation,irritablebowelsyndrome,autoimmunedisorders,neurologicalconditions,obesity,metabolicsyndromeanddiabetes,multiplesclerosis,andParkinson'sdisease2015/5/16AnaerobicBacteria-Junqi'sLecture56In2012,ateamofresearchersfromtheMassachusettsInstituteofTechnologyfoundedOpenBiome,thefirstpublicstoolbankintheUnitedStates2015/5/16AnaerobicBacteria-Junqi'sLecture5758“Fleshbug”NewDelhiMetalo-Beta-Lactamase-1:firstdetectedinaKlebsiellapneumoniae

“Flesheating”ClostridiumdifficilebugCarbapenem“Superbug”2015/5/16AnaerobicBacteria-Junqi'sLecture59Sugarhelpsantibioticsworkbetter

Issugartoxic?MousewithurinarytractinfectionWhensugarmeetantibiotics,whatwillbehappened?2015/5/16AnaerobicBacteria-Junqi'sLecture6060Aspoonfulofsugarnotonlymakesmedicineeasiertoswallow,butitalsomightincreaseitspotencyTheresultsshowsugarcanmakecertainantibioticsmoreeffectiveatwipingoutbacterialinfections.Thesugartricksbacteriathatwouldotherwiseplaydeadintoconsumingtheantibioticandthereforeendupreallydead.StaphStrepTB2015/5/16AnaerobicBacteria-Junqi'sLecture6161Sofar,studieshaveonlybeenconductedinanimals,andmoreresearchisneededtoseeifthesameresultsholdtrueinhumans.Iftheydo,it'spossibletheantibioticswealreadyhavecouldbeimprovedwithoutneedingtomakenewdrugs,whichcanbeexpensive.Inaddition,patientsmaynotneedtotakemultipledosesofantibioticstocombatrecurrentinfections.WhyandHowitcouldbehappened?2015/5/16AnaerobicBacteria-Junqi'sLecture62Persistentbacteria:somebacterialinfections,includingstaph,strep,tuberculosis,earinfectionsandurinarytractinfections,becomechronicandreoccurevenwhentheyaretreatedwithantibiotics.Thishappensbecausesomebacteria,calledpersisters,areabletosurviveantibiotictreatment.Infectionswithbacterialpersisterscanlastmonthsandreturnevenafterthepatientappearstorecover.Theseinfectionscanalsospreadtootherpartsofthebody,suchasthekidneys.Thedifferentbetweenbacterialpersistersandantibiotic-resistantbacteria2015/5/16AnaerobicBacteria-Junqi'sLecture63Thesugarwakesthebacteriaupandmakingthemeattheantibiotics.Collinsandhiscolleaguestestedtheirtechniqueonmicewithurinarytractinfections.Treatmentwithantibioticsplussugarwasabletokill99.9percentofthebacteriapersisters(inthiscase,E.colibacteria).Treatmentwiththeantibioticalonehadnoeffect.Thetechniqueonlyworksforaclassofantibioticscalledaminoglycoside,whichincludegentamicinandkanamycin.Thetypeofsugarusedduringtreatmentcanmakeadifference.Forinstance,theresearcherswereonlyabletokillStaphylococcusaureus,whichcausesstaphinfections,byusingthesugarfructoseinadditiontoantibiotics.TB?Strep?2015/5/16AnaerobicBacteria-Junqi'sLecture64Obstacles

Thestudyshowsthetreatmentworksonartificialurinarytractinfectionsinmice,butmoreresearchisneededtodetermineifitwillworkinhumansaswell,Balabansaid.Oneproblemwillbegettingthesugarcompoundstothesiteofinfection,Balabansaid.Sugargiventoahumanwillbebrokendownandwillnotnecessarilytraveltothesiteofinfection,shesaid.Theyhaveyettotesttheirtechniqueondrugsthataregivenorally.Henotesthetypeofsugarusedtotreatthemiceinthestudy,mannitol,isnotmetabolizedbythehumanbodyandmaybeeasiertotransporttothesiteofinfection.

2015/5/16AnaerobicBacteria-Junqi'sLecture65Chaudharietal.JournalofNanobiotechnology(2015)13:23DOI10.1186/s12951-015-0085-52015/5/16AnaerobicBacteria-Junqi'sLecture66Figure4Evaluationoftheminimuminhibitoryconcentrations(MICs)usingtheredoxresazurindye-basedmicrotiterbrothdilutionassay.1×105cfu/mLbacteriawereexposedtodoublingconcentrationsofnanocomposites.(a)SWCNTs-Agwithoutresazurin.(b)SWCNTs-Agwithresazurin.(c)pSWCNTs-Agwithoutresazurin.(d)pSWCNTs-Agwithresazurin.Alltheplateswereincubatedat37°Candtheopticaldensityat600nm(OD600)wasdeterminedafter24h.Allvalueswereconsideredtobesignificantatp≤0.05or0.01versusthecontrols(0μg/mLofSWCNTs-Agpresentinbacterialculture).**p≤0.01indicatinghighlysignificantdifferences.Errorbarsrepresentstandarddeviationsdeterminedfromatleastsixreplicates.2015/5/16AnaerobicBacteria-Junqi'sLecture67Figure10EvaluationofmorphologicalchangesinbacteriaupontheirinteractionwithSWCNTs-AgandpSWCNTs-AgbySEM(a-c)andTEM(d-j).(a)NontreatedSalmonellaTyphimurium.(b)SalmonellaTyphimuriumtreatedwithSWCNTs-Ag.(c)TreatmentwithpSWCNTs-Ag.(d)Non-treatedbacteria.(e-g)BacteriaexposedtoSWCNTs-Ag;(g)ismagnifiedinsetof(f).(h-j)BacteriaexposedtopSWCNTs-Ag;(j)ismagnifiedinsetof(i).Blacksolidarrowsindicatelysisofthecells.Whitesolidblockarrowsindicatedissolvedentities.Whitelinearrowsindicateporeformation.Blackarrow-headsrepresentnanocomposites,whereaswhitearrow-headsindicatecelldebris.Dottedlineblackarrowsshowemptyghostcells.Twoheadedarrowindicatesthepresenceofnanocomposites.2015/5/16AnaerobicBacteria-Junqi'sLecture68Figure9ToxicityevaluationofSWCNTs-AgandpSWCNTs-AginA549cellsbyTEM(a-e)andDNAfragmentationassay(f).(a)non-treatedA549cells.(b)A549cellstreatedwith31.25μg/mLofSWCNTs-Ag.(c)A549cellstreatedwith15.6μg/mLofSWCNTs-Ag.(d)A549cellstreatedwith31.25μg/mLofpSWCNTs-Ag.(e)A549cellstreatedwith15.6μg/mLofpSWCNTs-Ag,N:nucleus;CY:cytoplasm;CO:cellorganelle.(f)DNAfragmentationassay,Lane1:100bpDNAladder;2:nontreatedcontrol;3:cellstreatedwith31.25μg/mLofSWCNTs-Ag;4:cellstreatedwith15.6μg/mLofSWCNTs-Ag;5:cellstreatedwith31.25μg/mLofpSWCNTs-Ag;6:cellstreatedwith15.6μg/mLofpSWCNTs-Ag.2015/5/16AnaerobicBacteria-Junqi'sLecture69Figure12SchematicpresentationofmechanismofactionofSWCNTS-AgandpSWCNTs-Ag.OurresultsdemonstratedthatSWCNTs-Agdown-regulatesomeofthegenesassociatedwithmetabolismandoutermembraneintegrity,howevertheyarestilltoxictohumancellsattheirbactericidalconcentration(62.5μg/mL).Ontheotherhand,pegylationofSWCNTs-Ag(pSWCNTs-Ag)didnotaffecttheirantibacterialactivity(62.5μg/mL),butreducedtheirtoxicitytohumancells.Inaddition,pSWCNTsdown-regulatedtheexpressionofgenesassociatedwithquorumsensing,biofilmformationandvirulenceinSalmonella.2015/5/16AnaerobicBacteria-Junqi'sLecture70無芽胞厭氧菌屬人體內(nèi)的正常菌群，包括革蘭陽性和革蘭陰性的球菌和桿菌；某些特定狀態(tài)下，這些厭氧菌作為條件致病菌可導(dǎo)致內(nèi)源性感染。2015/5/16AnaerobicBacteria-Junqi'sLecture71主要種類、性狀和在感染中的作用1.革蘭陰性厭氧桿菌

脆弱類桿菌（B.fragilis）：臨床上最常見的無芽胞厭氧菌分離株；腹部、會(huì)陰部感染常見。

韋榮菌屬最重要，咽喉部主要厭氧菌，常為混合感染菌之一。2015/5/16AnaerobicBacteria-Junqi'sLecture722.革蘭陽性厭氧球菌消化鏈球菌屬：在臨床厭氧菌分離株

中僅次于脆弱類桿菌，主要寄居于陰道。丙酸桿菌：能發(fā)酵糖類產(chǎn)生丙酸。

痤瘡丙酸桿菌（P.acnes）雙歧桿菌屬：正常腸道菌群，在大腸中起重要的調(diào)節(jié)作用。真桿菌屬2015/5/16AnaerobicBacteria-Junqi'sLecture73（一）致病條件

寄居部位改變

宿主免疫力下降

菌群失調(diào)

厭氧微環(huán)境

（二）感染特征

內(nèi)源性感染；呈慢性

大多為化膿性感染；

分泌物或膿液粘稠；

有惡臭，使用氨基糖

苷類抗生素長期無效；

分泌物直接涂片可見

細(xì)菌，但普通培養(yǎng)法

無細(xì)菌生長。2015/5/16AnaerobicBacteria-Junqi'sLecture74（三）所致疾病

敗血癥

中樞神經(jīng)系統(tǒng)感染

口腔與牙齒感染

呼吸道感染

腹部和會(huì)陰部感染

女性生殖道感染2015/5/16AnaerobicBacteria-Junqi'sLecture751.標(biāo)本采取采取后立刻放入?yún)捬鯓?biāo)本瓶中，迅速送檢。2.直接涂片鏡檢3.分離培養(yǎng)與鑒定微生物學(xué)檢查法2015/5/16AnaerobicBacteria-Junqi'sLecture76破壞其成為條件致病菌的條件合理使用抗生素防治原則2015/5/16AnaerobicBacteria-Junqi'sLecture77與人類疾病相關(guān)的主要無芽胞厭氧菌2015/5/16AnaerobicBacteria-Junqi'sLecture78思考題1.試比較破傷風(fēng)梭菌和產(chǎn)氣莢膜梭菌的致病條件及其致病機(jī)制2.簡述破傷風(fēng)和氣性壞疽的防治原則ClinicalCaseA24-year-oldwomanwasseeninahospitalemergencydepartmentwithahistoryofnausea,vomiting,andnon-bloodydiarrhea,whichprogressedtobloodydiarrhea.Fourdaysearliershehadeatenahamburgeratafast-foodrestaurant.Toreplacefluidlostfromdiarrhea,shewasgiven2litersofIVfluid.Herconditionimprovedandshewassenthomewithanti-nauseamedication.2015/5/16AnaerobicBacteria-Junqi'sLecture79Twodayslater,thesymptomshadnotresolved;thevomiting,nausea,andbloody