吳亦斐,劉 偉,謝 捷,吳琍敏,王 樂,陸 敏,孫愛華,謝 立
杭州地區流行非結核分枝桿菌鑒定、易感因素和耐藥性分析
吳亦斐1,劉 偉1,謝 捷1,吳琍敏1,王 樂1,陸 敏1,孫愛華2,謝 立1
目的了解近年杭州地區非結核分枝桿菌(NTM)感染、優勢菌種及其耐藥性。方法采用PNB/TCH生長試驗對1 972例患者分枝桿菌陽性培養物標本中NTM進行初步鑒定。采用分枝桿菌分子線性探針法和16S rRNA基因PCR產物測序鑒定NTM菌種。分析性別和年齡對NTM易感性的影響。采用濃度比例法檢測NTM分離菌株對異煙肼(INH)、利福平(RFP)、鏈霉素(SM)、乙胺丁醇(EMB)、氧氟沙星(OFX)、卡那霉素(KM)的敏感性。結果9.8%(193/1 972)分枝桿菌陽性培養物標本PNB/TCH生長試驗結果陽性。分子線性探針法和16S rRNA基因PCR產物測序結果顯示,193例PNB/TCH生長試驗陽性標本中,66.3%為單一NTM、18.1%為2種分枝桿菌、8.3%為結核分枝桿菌、7.3%為非分枝桿菌屬細菌感染。173株NTM(單一感染128株+混合感染45株)中,胞內分枝桿菌占57.8%,其次為膿腫分枝桿菌、堪薩斯分枝桿菌、龜分枝桿菌和鳥分枝桿菌(12.1%、9.8%、9.8%和5.8%)。35例分枝桿菌混合感染標本中,28.5%和20.0%分別為胞內分枝桿菌或龜分枝桿菌與結核分枝桿菌混合感染。NTM感染者男性多于女性(1.67∶1),50歲以上人群感染率(80.4%)高于50歲以下人群(P<0.01),肺部感染比例(95.1%)遠高于其他部位(P<0.01)。NTM分離株對INH耐藥率為100%,對其他5種抗結核藥物的耐藥率也高達70.3%~90.6%。結論胞內分枝桿菌是杭州地區近年優勢流行的NTM菌種,NTM主要引起肺部感染且中老年人易感,NTM臨床菌株對常用抗結核藥物有很高的耐藥性。
非結核分枝桿菌;分離與鑒定;優勢流行;易感因素;耐藥性
非結核分枝桿菌(nontuberculous mycobacteria,NTM)是指結核分枝桿菌復合群結核分枝桿菌(Mycobacteriumtuberculosis)、牛分枝桿菌(M.bovis)、非洲分枝桿菌(M.africanum)和田鼠分枝桿菌(M.microti)以及麻風分枝桿菌(M.leprae)以外的分枝桿菌屬其他分枝桿菌。NTM可侵犯人體各種器官和組織,但主要引起肺部感染,其致病過程和臨床表現與肺結核極為相似,且又多見于原發慢性肺部疾病愈后患者,故未進行NTM分離培養及鑒定時,常被誤診為肺結核病[1]。近年來,NTM感染性疾病的發病率不斷增高,但NTM分離鑒定有一定難度且NTM往往對多種抗結核藥物耐藥,故NTM感染性疾病診治成為臨床難點之一[1-5]。本研究中,我們對近年收集的1 972例杭州地區分枝桿菌陽性培養物進行了NTM分離鑒定及其藥物敏感試驗,以期了解本地區NTM流行現狀、致病特點及其耐藥性。
1.1臨床標本來源 2015年1月-2016年12月來自杭州地區各區縣結核病定點醫院1 972例患者臨床標本分枝桿菌陽性培養物。
1.2NTM初步鑒定 采用硝基苯甲酸(PNB)和噻吩-2-羧酸肼(TCH)鑒別培養法對上述分枝桿菌陽性培養物進行初篩及鑒定,若該菌在PNB鑒別培養基上能生長,則初步判定為NTM[6]。PNB和TCH培養基均購自杭州市創新生物技術有限公司。
1.3細菌DNA模板制備 刮取NTM菌苔懸于0.01 mol/L、pH7.4磷酸緩沖鹽水(PBS)中,95 ℃水浴滅活20 min,室溫冷卻后12 000 r/min離心5 min(4 ℃),取菌體沉淀用細菌基因組DNA提取試劑盒(OMEGA)提取DNA,紫外分光光度法測定其純度和濃度[7]。
1.4寡核苷酸探針雜交試驗 采用分枝桿菌分子線性探針法菌種鑒定試劑盒(GenoType Mycobacterium CM/AS Kit, Hain Lifescience GmbH)對初篩判定為NTM菌株進行菌種鑒定。根據該試劑盒操作說明書,分別采用PCR擴增靶基因片段、擴增產物與膜條上線性排列的寡核苷酸探針雜交、雜交條帶顯色和結果判讀。
1.516S rRNA基因檢測與產物測序 不同分枝桿菌16S rRNA引物由上海生工生物工程技術有限公司(Sangon)提供,Ex-Taq高保真PCR試劑盒由大連寶生物技術有限公司(TaKaRa)提供,16S rRNA基因擴增產物由Sangon公司測序,對初篩判定為NTM菌株進行菌種再次鑒定。
1.6藥物敏感試驗 根據我國《結核病實驗室檢驗規程》采用間接比例法檢測獲得純培養的NTM菌株藥物敏感性[8]。接種環刮取一環各NTM菌株對數生長期培養物,無菌磨砂管碾磨后用PBS配制成1.0麥氏濃度菌液,然后用PBS分別稀釋成10-2和10-4CFU/mL菌液,取0.01 mL各稀釋菌液均勻密集劃線接種于不同含藥培養基上,37 ℃培養4~8周觀察結果。含藥培養基所用異煙肼(INH)、利福平(RFP)、鏈霉素(SM)和乙胺丁醇(EMB)購自杭州市創新生物技術有限公司,氧氟沙星(OFX)和卡那霉素(KM)購自珠海貝索生物技術有限公司
2.1NTM菌株初步鑒定結果 上述1 972例分枝桿菌陽性培養物中,193例在PNB和TCH鑒別培養基上均有分枝桿菌生長,初步判定為NTM。
2.2分子線性探針法和16S rRNA基因測序法鑒定結果 分子線性探針法檢測結果顯示,上述193例初步判定為NTM標本中,8.3%(16/193)為結核分枝桿菌、7.3%(14/193)為非分枝桿菌屬細菌、66.3%(128/193)檢出單一NTM、18.1%(35/193)同時檢出兩種分枝桿菌。16S rRNA基因PCR產物測序法對193例初步判定為NTM標本的鑒定結果與分子線性探針法完全相同。128例單一NTM感染標本中,65.5%(84/128)為胞內分枝桿菌(Mycobacteriumintracellulare),14.8%(19/128)、7.8%(10/128)和5.5%(7/128)分別為膿腫分枝桿菌(Mycobacteriumabscessus)、堪薩斯分枝桿菌(Mycobacteriumkansasii)和鳥分枝桿菌(Mycobacteriumavium),其余8例鑒定出6種NTM(表1)。35例分枝桿菌混合感染標本中,28.5%(10/35)為胞內分枝桿菌+結核分枝桿菌混合感染,20.0%(7/35)、14.3%(5/35)和14.3%(5/35)分別為龜分枝桿菌+結核分枝桿菌、堪薩斯分枝桿菌+結核分枝桿菌和胞內分枝桿菌+龜分枝桿菌混合感染,其余8例分屬6種混合感染模式(表2)。檢出的173株NTM(單一感染128株+混合感染45株)中,57.8%(100/173)為胞內分枝桿菌,12.1%(21/173)、9.8%(17/173)、9.8%(17/173)和5.8%(10/173)分別為膿腫分枝桿菌、堪薩斯分枝桿菌、龜分枝桿菌和鳥分枝桿菌(表3)。
2.3NTM感染標本類型與分布 163例NTM感染標本(單一感染128例+混合感染35例)中,93.3%(152/163)為痰液,其余6.7%(11/163)標本分別為血液(3例)、支氣管肺泡灌洗液(3例)、尿液(2例)、胸腹水(1例)、腸淋巴結穿刺液(1例)和頸部淋巴結穿刺液(1例),肺部感染比例95.1%(155/163)遠高于其他部位4.9%(8/163)(P<0.01)。
表1 128例單一NTM感染標本鑒定結果
Tab.1 Identification results of 128 cases with single NTM infection

非結核分枝桿菌NTM例數(n)Case百分率(%)Percentage胞內分枝桿菌M.intracellulare8465.5膿腫分枝桿菌M.abscessus1914.8堪薩斯分枝桿菌M.kansasii107.8鳥分枝桿菌M.avium75.5龜分枝桿菌M.chelonei21.6草分枝桿菌M.phlei21.6偶然分枝桿菌M.fortuitum10.8瘰疬分枝桿菌M.scrofulaceum10.8下出分枝桿菌M.shimoidei10.8膿毒分枝桿菌亞種M.stomatepiae10.8合計Total128100
表2 35例分枝桿菌混合感染標本鑒定結果
Tab.2 Identification results of 35 cases with Mycobacteria-mixed infection

混合感染模式Mixedinfectionmode例數(n)Case百分率(%)Percentage胞內分枝桿菌+結核分枝桿菌M.intracellulare+M.tuberculosis1028.5龜分枝桿菌+結核分枝桿菌M.chelonei+M.tuberculosis720.0堪薩斯分枝桿菌+結核分枝桿菌M.kansasii+M.tuberculosis514.3胞內分枝桿菌+龜分枝桿菌M.intracellulare+M.chelonei514.3偶然分枝桿菌+結核分枝桿菌M.fortuitum+M.tuberculosis25.7鳥分枝桿菌+龜分枝桿菌M.avium+M.chelonei25.7膿腫分枝桿菌+結核分枝桿菌M.abscessus+M.tuberculosis12.9胞內分枝桿菌+鳥分枝桿菌M.intracellulare+M.avium12.9龜分枝桿菌+堪薩斯分枝桿菌M.chelonei+M.kansasii12.9堪薩斯分枝桿菌+膿腫分枝桿菌M.kansasii+M.abscessus12.9合計Total35100
表3 不同類型NTM感染標本綜合結果
Tab.3 Combined results of cases with different NTM-infected types

非結核分枝桿菌NTM感染類型Infectiontype單一感染Singleinfection混合感染Mixedinfection例數(n)Case百分率(%)Percentage胞內分枝桿菌M.intracellulare841610057.8膿腫分枝桿菌M.abscessus1922112.1堪薩斯分枝桿菌M.kansasii107179.8龜分枝桿菌M.chelonei215179.8鳥分枝桿菌M.avium73105.8偶然分枝桿菌M.fortuitum1231.7草分枝桿菌M.phlei2021.2瘰疬分枝桿菌M.scrofulaceum1010.6下出分枝桿菌M.shimoidei1010.6膿毒分枝桿菌亞種M.stomatepiae1010.6合計Total12845173100
2.4NTM感染患者性別和年齡分布 163例NTM感染標本(單一感染128例+混合感染35例)中,62.6%(102/163)為男性,37.4%(61/163)為女性,男女比例為1.67∶1,年齡范圍19~96歲,80.4%(131/163)患者年齡為50歲以上(表4),其感染率顯著高于50歲以下人群(P<0.01)。
表4 163例NTM感染患者性別和年齡分布
Tab.4 Distribution of sex and age of 163 NTM-infected patients

年齡(歲)Age例數/百分率(n/%)Case/Percentage男性Male女性Female合計(n/%)Total19~304/2.55/3.09/5.530~403/1.84/2.57/4.340~5010/6.16/3.716/9.850~6013/8.012/7.425/15.360~7026/16.015/9.241/25.270~8028/17.214/8.642/25.880~18/11.05/3.023/14.1合計(Total)102/62.661/37.4163/100
2.5NTM藥敏試驗結果 從128例單一感染NTM患者標本中獲得純培養的128株NTM臨床菌株均對異煙肼耐藥,對利福平、鏈霉素、乙胺丁醇、氧氟沙星和卡那霉素總耐藥率分別為90.6%(116/128)、82.8%(106/128)、84.4%(108/128)、86.7%(111/128)和70.3%(90/128)(表5)。
近年來,NTM感染所致疾病的發病率呈上升趨勢,全國不少地區分枝桿菌陽性培養物標本中NTM檢出率升高[3,9-10]。本研究中,我們檢測了2015年1月~2016年12月杭州地區1 972例患者臨床標本分枝桿菌陽性培養物,最終確定128例單一感染NTM、35例兩種分枝桿菌混合感染,NTM總感染率或分離率為8.3%(163/1972),遠低于全國20%~25%的感染率或分離率[9-11]。PNB/TCH生長試驗是經典的鑒別結核分枝桿菌復合群和NTM初篩試驗,一般認為該法簡便、價廉,主要缺點為耗時、不能確定菌種。我們的PNB/TCH生長試驗結果顯示,1 972例分枝桿菌陽性培養物中,193例能在PNB鑒別培養基上生長,但有15.5%(30/193)經分子線性探針法和16S rRNA基因測序法檢測后確定非為NTM,其中16例為結核分枝桿菌、14例為非分枝桿菌屬細菌感染。此外,分子線性探針法和16S rRNA基因測序法檢測結果顯示,兩種方法對193例PNB/TCH生長試驗陽性NTM標本鑒定結果完全相同。上述PNB/TCH生長試驗所鑒定的NTM中存在結核分枝桿菌和非分枝桿菌屬細菌的情況以往也有報道[12]。上述資料提示,耐PNB結核分枝桿菌或非分枝桿菌屬細菌是PNB/TCH生長試驗初篩NTM誤差較大的主要原因,PNB/TCH生長試驗必須聯合分子線性探針法或16S rRNA基因測序法才能確定NTM。
表5 128株NTM對6種抗結核藥物的耐藥率
Tab.5 Resistance rates against 6 antituberculosis drugs of 128 NTM isolates

非結核分枝桿菌NTM株數(n)Case耐藥株數/耐藥率(n/%)Resistantstrains/Resistancepercentage異煙肼INH利福平RFP鏈霉素SM乙胺丁醇EMB氧氟沙星OFX卡那霉素KM胞內分枝桿菌M.intracellulare8484/10083/98.865/77.471/84.578/92.956/66.7膿腫分枝桿菌M.abscessus1919/10018/94.718/94.719/10017/89.515/78.9堪薩斯分枝桿菌M.kansasii1010/1005/50.09/90.05/50.03/30.09/90.0鳥分枝桿菌M.avium77/1005/71.46/85.77/1007/1003/42.9龜分枝桿菌M.chelonei22/1000/02/1002/1002/1002/100草分枝桿菌M.phlei22/1002/1002/1002/1002/1002/100偶然分枝桿菌M.fortuitum11/1000/01/1001/1001/1001/100瘰疬分枝桿菌M.scrofulaceum11/1001/1001/1000/01/1001/100下出分枝桿菌M.shimoidei11/1001/1001/1000/00/00/0膿毒分枝桿菌亞種M.stomatepiae11/1001/1001/1001/1000/01/100合計Total128128/100116/90.6106/82.8108/84.4111/86.790/70.3
本研究中共檢出173例NTM(單一感染128例+混合感染45例)感染病例,引起混合感染NTM均在單一感染10個NTM種范圍內。值得關注的是,高達57.8%(100/173)的分離菌株為胞內分枝桿菌,其次為膿腫分枝桿菌12.1%(21/173)、堪薩斯分枝桿菌9.8%(17/173)、龜分枝桿菌9.8%(17/173)和鳥分枝桿菌5.8%(10/173),其余5種NTM合計僅占4.6%(8/173),表明本地區以胞內分枝桿菌為優勢致病NTM,與臨近上海地區龜分枝桿菌感染率最高(26.7%)明顯不同[13]。在NTM中,鳥胞內分枝桿菌復合群(MAC)和快速生長型分枝桿菌(RGM)感染最常見[1]。Hoefsloot等(2013)報道,約50%NTM感染者的病原體為MAC[14]。澳大利亞和日本NTM感染者的病原體為MAC的比例分別高達90%和74%[15]。我國福建和山東地區NTM感染的病原體也以MAC為主[10,16],但上海和廣州地區以RGM為主要,其次為MAC[3,13]。本研究中,屬于MAC的胞內分枝桿菌、堪薩斯分枝桿菌和鳥分枝桿菌共檢出127例,占73.4%(127/173),屬于RGM的膿腫分枝桿菌、龜分枝桿菌和偶然分枝桿菌共檢出41例,占23.7%(41/173),與福建和山東地區相似而與上海和廣州地區不同。不同地區優勢流行NTM與地理、氣候及環境差異有關[1]。
NTM為條件致病菌,其致病性遠低于結核分枝桿菌,免疫力下降是NTM主要易感因素[1]。我們的研究結果也顯示,50歲以上人群感染率顯著高于50歲以下人群(P<0.01),提示中老年人群可因免疫力下降而導致NTM感染率增高。此外,本研究中發現35例患者為兩種分枝桿菌混合感染,提示混合感染可能是NTM致病另一重要途徑。Simons等(2011)報道,67.2%東亞地區NTM引起肺部感染,其次為淋巴結病變[17]。本研究中,95.1%患者為NTM肺部感染,其比例不僅遠高于其他感染部位(P<0.01),同時也高于Simons等報道的肺部感染率(P<0.05)。
異煙肼、鏈霉素、利福平和乙胺丁醇是臨床一線抗結核藥物,氧氟沙星和卡那霉素也用于治療結核病。如前所述,NTM通常對多種抗結核藥物耐藥[1-5]。本研究中,我們從單一NTM感染者標本中分離獲得了128株NTM菌株并對其耐藥性進行了檢測。藥物敏感試驗結果顯示,上述NTM菌株對6種抗結核藥物有很高的耐藥率,對異煙肼耐藥率為100%,對其他5種抗結合藥物耐藥率也高達70.3%~90.6%。上述資料提示,臨床診斷為NTM感染性疾病后,應分離菌種進行藥物敏感試驗,根據藥物敏感試驗結果選擇多種抗結核藥物進行治療以提高療效。
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IdentificationofpredominantprevailingnontuberculosismycobacteriainHangzhouandanalysisoftheirpredisposingfactorsanddrugresistance
WU Yi-fei1, LIU Wei1, XIE Jie1, WU Li-min1, WANG Le1, LU Min1, SUN Ai-hua2, XIE Li1
(1.HangzhouCenterforDiseasesControlandPrevention,Hangzhou310021,China;2.HangzhouMedicalCollege,Hangzhou310053,China)
This study is aim to determine the predominant prevailing nontuberculosis mycobacteria (NTM) in Hangzhou and to understand the predisposing factors and drug resistance of NTM. PNB/TCH growth tests were used to preliminarily identify the NTM in the mycobacterium-positive culture samples from 1 972 patients. The species of NTM isolates were confirmed using mycobacterium molecular linear probe method and sequencing of PCR product of 16S rRNA gene. The influence of sex and age on predisposing factors of NTM was subsequently analyzed. Concentration proportional method was applied to detect the susceptibility of NTM isolates to armazide, rifampicin, streptomycin, ethambutol, ofloxacin and kanamycin. Results of PNB/TCH growth tests showed that 9.8% (193/1 972) of the 1 972 mycobacterium-positive culture samples were positive. The mycobacterium molecular linear probe hybridization and PCR product sequencing confirmed that in the 193 samples with positive results of PNB/TCH growth tests, 66.3%, 18.1%, 8.3% and 7.3% were infected with NTM alone, two mycobacteria,Mycobacteriumtuberculosisand bacteria that not belonging to the genus ofMycobacteria, respectively. In the 173 NTM isolates (128 with single infection and 45 with mixed infection), 57.8% were identified asMycobacteriumintracellulare, followed byMycobacteriumabscessus(12.1%),Mycobacteriumkansasii(9.8%),Mycobacteriumchelonei(9.8%) andMycobacteriumavium(5.8%). In the 35 mixed infection samples, 28.5% and 20.0% were the co-infection ofM.intracellulareandM.cheloneiwithM.tuberculosis, respectively. Male patients infected with NTM were more than female patients (1.67∶1) and the infection rate (80.4%) of populations with age over 50 years old was significantly high than that with lower than 50 years old (P<0.01). Pulmonary infection proportion (95.1%) of NTM was significantly higher than other positions of body (P<0.01). 100% of NTM isolates were resistant to armazide while the resistance rates of the isolates against the other 5 antituberculosis drugs were as high as 70.3%-90.6%. As the conclusion of this study,M.intracellulareis the predominant prevailing NTM species in the recent years in Hangzhou, NTM mainly causes pulmonary infection and middle-aged and old people are easily infected by NTM. Moreover, NTM isolates have high resistance against commonly used antituberculosis drugs.
nontuberculosis mycobacteria; isolation and identification; predominant prevalence; predisposing factors; drug resistance
Xie Li, Email: hbxieli@yeah.net
10.3969/j.issn.1002-2694.2017.10.006
浙江省衛生高層次創新人才培養工程項目(No.2012-241)資助
謝立,Email:hbxieli@yeah.net
1.杭州市疾病預防控制中心,杭州 310021;
2.杭州醫學院,杭州 310053
378
A
1002-2694(2017)10-0882-06
Supported by Zhejiang Provincial Program for the Cultivation of High-level Innovative Health Talents (No.2012-241)
2017-05-03編輯李友松