Ⅰ类整合子与鲍曼不动杆菌耐药性相关性研究

目的 了解鲍曼不动杆菌整合子分布情况,探讨Ⅰ类整合子与其耐药性的关系.方法 琼脂稀释法检测65株鲍曼不动杆菌耐药率,聚合酶链反应(PCR)检测Ⅰ～Ⅲ类整合子基因;对Ⅰ类整合子阳性菌株进行可变区扩增及序列分析.结果 Ⅰ类整合子检出率为60%(39/65),未检出Ⅱ、Ⅲ类整合子;Ⅰ类整合子阳性菌株对14种抗菌药物的耐药率高于阴性菌株(P＜0.05);92%(36/39)的Ⅰ类整合子阳性菌株可变区扩增阳性,序列分析显示携带3种耐药基因aacA4、aadA1和catB8.结论 Ⅰ类整合子与鲍曼不动杆菌耐药性密切相关,在鲍曼不动杆菌多药耐药性形成机制中起重要作用.     

整合子在鲍曼不动杆菌耐药中的作用研究

目的调查本院鲍曼不动杆菌耐药谱并了解其整合子流行情况;检测鉴定整合子类型并分析其与耐药的相关性。方法收集本院2007年临床分离鲍曼不动杆菌85株,KB法测定其药敏结果。PCR法扩增整合子的整合酶基因,并进一步鉴定整合子种类。分析鲍曼不动杆菌整合子携带与其耐药之间的关系。PCR法扩增整合子开放阅读框,观测其多态性并挑选个别产物测序。结果 85株鲍曼不动杆菌除对亚胺培南、头孢哌酮/舒巴坦耐药率低于10%,其他15种常用抗菌药物的耐药率均超过30%。67.1%(57/85)的鲍曼不动杆菌中检出整合子;进一步鉴定结果显示均为Ⅰ类整合子,未检出Ⅱ类和Ⅲ类整合子。携带整合子鲍曼不动杆菌株对14种抗菌药物耐药率高于不携带整合子鲍曼不动杆菌株耐药率。开放阅读框可变区扩增产物为0.3～2.5 KB不等条带,测序结果证实含有多药耐药基因编码。结论本院鲍曼不动杆菌耐药率高,以多药耐药菌株为主,携带Ⅰ类整合子率较高;携带整合子鲍曼不动杆菌对14种抗菌药的耐药率明显增高,整合子与鲍曼不动杆菌的多重耐药性具有密切相关性。     

鲍曼不动杆菌的耐药性与Ⅰ类整盒子的相关研究

目的了解该院鲍曼不动杆菌的流行趋势以及鲍曼不动杆菌与Ⅰ类整合子的耐药关系。方法用该院临床常用22种抗菌药物来检测临床分离的鲍曼不动杆菌的敏感性。用PCR检测鲍曼不动杆菌Ⅰ类整合子酶基因,再扩增部分Ⅰ类整合子酶基因的可变区,对整合子可变区进行基因测序分析。结果鲍曼不动杆菌的耐药现象十分严重,呈多重耐药性。鲍曼不动杆菌对CPZ/SB耐药率为1.2%,对替加环素、左旋氧氟沙星、亚胺培南、比阿培南、阿米卡星等几种抗菌药物的耐药率为15.4%~69.5%,对其他抗菌药物均在71%以上。102株中有72株菌株含Ⅰ类整合子(阳性率为70.2%),Ⅰ类整合子阳性株的耐药性均高于阴性株,对Ⅰ类整合子可变区采用双酶切分析产生类似的酶切条带,说明该院鲍曼不动杆菌具有同源性。Ⅰ类整合子基因盒序列分析表明该院鲍曼不动杆菌Ⅰ类整合子携带aacA4、catB8和aadA1 3种耐药基因。结论该院2010~2013年,鲍曼不动杆菌对头孢菌素类、广谱青霉素、氨基糖苷类和氟喹诺酮类呈高度耐药及严重的多重耐药现状,说明治疗鲍曼不动杆菌所致感染的抗菌药物选择已十分有限。Ⅰ类整合子与鲍曼不动杆菌多重耐药性密切相关。     

南京地区鲍曼不动杆菌中整合子流行现状及携带的耐药基因分析

目的研究南京地区鲍曼不动杆菌中整合子的流行现状、与耐药的相关性及携带的耐药基因。方法收集106株南京地区鲍曼不动杆菌,纸片扩散法测定其药敏情况;PCR-限制性片段长度多态性(RFLP)筛查整合子并分类;PCR法扩增整合子可变区;联合RFLP和DNA测序技术分析整合子携带的耐药基因。结果52.8%(56/106)鲍曼不动杆菌检出整合子,PCR—RFLP结果显示均为Ⅰ类整合子;94.6%(53/56)整合子阳性菌株可变区扩增阳性,扩增片段大小为0.15～2.8kb;共检出7种不同的可变区,含有编码对氨基糖苷类抗生素(aadA1、aadA2、aadA5、aadB、aacA4)、磺胺类抗菌药(dfrⅫ、dfr17)、β内酰胺类抗生素(bla_(axa-10))和氯霉素(catB-like、catB8)耐药的基因及2个功能不清的开放阅读框(orfF、orfI);发现1例新型基因盒组合形式orfI—aadA1,GenBank基因号为DQ092497。结论Ⅰ类整合子广泛存在于南京地区鲍曼不动杆菌中;整合子与鲍曼不动杆菌的耐药和多重耐药有关;鲍曼不动杆菌整合子主要携带氨基糖苷类耐药基因。     

Ⅰ类整合子在多重耐药鲍曼不动杆菌中的作用研究

目的了解我院多重耐药鲍曼不动杆菌临床分离株中Ⅰ类整合子的流行情况,建立一种快速简便的Ⅰ类整合子聚合酶链反应（PCR）检测方法。方法收集我院2008年9月至2010年9月临床分离的鲍曼不动杆菌63株,用MIC法检测耐药性,PCR技术检测Ⅰ类整合子基因。结果 63株鲍曼不动杆菌中Ⅰ类整合子基因阳性率56%（35株）。Ⅰ类整合子阳性和阴性的鲍曼不动杆菌对各种抗生素的耐药性存在明显差异。结论我院多重耐药鲍曼不动杆菌中Ⅰ类整合子携带率高,携带的耐药基因为aaeA4、catB8和aadA1。PCR技术可以方便快速地检出Ⅰ类整合子。     

苏州地区鲍曼不动杆菌中Ⅰ类和Ⅱ类整合子的分布及其基因盒结构分析

摘要：目的: 分析Ⅰ类和Ⅱ类整合子在苏州地区临床分离的鲍曼不动杆菌中分布情况及其基因盒结构。 方法：用PCR法检测69株鲍曼不动杆菌中Ⅰ类和Ⅱ类整合酶基因及整合子携带率,基因测序技术对其可变区进行分析;重复序列引物聚合酶链反应（REP-PCR）对Ⅰ类整合子阳性菌株进行基因分型,分析其同源性。 结果：69株鲍曼不动杆菌中Ⅰ类整合子阳性29株,占42.0%,未检测到Ⅱ类整合子;基因盒结构分析共检出6种基因盒,分别为aacA4,aacC1,catB8,aadA1,orfX和orfX′,以5′CS-aacA4-catB8-aadA1-3′CS基因盒排列为主;REP-PCR法将29株Ⅰ类整合子阳性菌株分成I~V型,其中Ⅲ型为主要流行型别。 结论：苏州地区鲍曼不动杆菌中的整合子携带率较高,主要以Ⅰ类Ⅲ型为主。     

鲍曼不动杆菌整合子与耐药性的相关性研究

目的调查鲍曼不动杆菌中Ⅰ类、Ⅱ类和Ⅲ类整合子的存在情况,分析整合子与鲍曼不动杆菌耐药性的关系。方法测定93株鲍曼不动杆菌对抗菌药物的敏感性;应用简并引物PCR方法,同时扩增整合子5’保守区的I类、Ⅱ类和Ⅲ类整合酶基因,对阳性PCR产物用限制性内切酶Hinf I作限制片段长度多态性（RFLP）分析进行整合子分类。结果 22株鲍曼不动杆菌检测出Ⅰ类整合子,未检出Ⅱ类和Ⅲ类整合子。Ⅰ类整合子阳性的菌株对抗菌药物的耐药率普遍比整合子阴性的菌株高。结论鲍曼不动杆菌临床分离株的耐药性强,细菌的多重耐药性与Ⅰ类整合子的存在相关。     

多重耐药鲍曼不动杆菌对氨基糖苷类药物耐药机制分析

目的了解本院多重耐药鲍曼不动杆菌(MDRAB)分子流行病学特征和氨基糖苷类耐药机制,为临床合理用药及控制院内感染提供依据。方法用纸片扩散法和琼脂稀释法检测泛耐药株对抗菌药物的敏感性,特异性PCR检测氨基糖苷类耐药基因、intI 1、intI 2基因及可变区。基因外重复回文序列(REP)-PCR分析菌株同源性。结果 67株MDRAB对多种抗菌药物广泛耐药,对阿米卡星100%耐药。PCR检测结果显示64株分离菌株携带Ⅰ类整合酶基因,其中61株可变区扩增阳性,分别为携带aacA4-catB-aadA1(2 300 bp)基因盒44株和携带aacC1-orfX-orfX-orfX’-aadA1基因盒(3 000 bp)17株;59株携带armA甲基化酶基因。REP-PCR分析显示耐药菌株属于6个克隆型,主要为A1～A3和B2型。结论甲基化酶介导本院鲍曼不动杆菌临床分离株对氨基糖苷类药物耐药。本院存在以A型和B型克隆株为主的感染流行,必须加强院内感染防控,切断克隆菌株的传播。     

多重耐药鲍曼不动杆菌整合子及菌株同源性分析

目的了解该院多重耐药鲍曼不动杆菌(MDRAB)整合子携带情况及菌株同源性,为临床合理用药及控制院内感染提供依据。方法收集多重耐药鲍曼不动杆菌101株,K-B纸片法测定其对12种抗菌药物的敏感性,琼脂稀释法测定其对多粘菌素B的MIC;PCR检测intlⅠ、intlⅡ和intlⅢ基因及可变区;基因外重复回文序列(REP)-PCR分析菌株同源性。结果 101株MDRAB仅对米诺环素和阿米卡星呈现出敏感性,敏感率分别为36.6%和33.7%,对其他10种药物的敏感率均为0;对多粘菌素B的MIC≤2μg/mL;96.0%(97/101)菌株携带Ⅰ类整合酶基因,DNA测序分析整合子可变区携带基因盒为aacA4-catB-aadA1(2 300bp)菌株47株,携带基因盒为aacC1-orfX-orfX-orfX′-aadA1(3 000bp)菌株44株;REP-PCR分析显示耐药菌株分为A～F型,A型中又分为A1～A4,分别为21、24、11和2株;B型分为B1～B2,分别为21和12株,C型和D型各2株,F型5株,E型1株。结论本院MDRAB主要携带Ⅰ类整合子,阳性菌株大多可扩增出可变区耐药基因盒;本院存在以A型和B型克隆株为主的感染流行,必须加强院内感染防控,切断克隆菌株的传播。     

鲍曼不动杆菌整合子与耐药性的相关性研究

目的 调查鲍曼不动杆菌中Ⅰ类、Ⅱ类和Ⅲ类整合子的存在情况,分析整合子与鲍曼不动杆菌耐药性的关系.方法 测定93株鲍曼不动杆菌对抗菌药物的敏感性;应用简并引物PCR方法,同时扩增整合子5’保守区的Ⅰ类、Ⅱ类和Ⅲ类整合酶基因,对阳性PCR产物用限制性内切酶HinfⅠ作限制片段长度多态性(RFLP)分析进行整合子分类.结果 ...     

Epidemiology of rifampin ADP-ribosyltransferase (arr-2) and metallo-beta-lactamase (blaIMP-4) gene cassettes in class 1 integrons in Acinetobacter strains isolated from blood cultures in 1997 to 2000

We characterized two new gene cassettes in an Acinetobacter isolate: one harbored the metallo-beta-lactamase (IMP-4) gene bla(IMP-4), the other harbored the rifampin ADP-ribosyltransferase (ARR-2) gene arr-2, and both arrayed with the aminoglycoside acetyltransferase [AAC(6')-Ib(7)] gene cassette aacA4 in two separate class 1 integrons. The epidemiology of these gene cassettes in isolates from blood cultures obtained from 1997 to 2000 was studied. Isolates bearing either the bla(IMP-4) or the arr-2 gene cassette or both represented 17.5% (10 of 57) of isolates in 1997, 16.1% (10 of 62) in 1998, 2.5% (1 of 40) in 1999, and 0% (0 of 58) in 2000. These two gene cassettes, probably borne on two separate integrons, were found in at least three genomic DNA groups, with evidence of clonal dissemination in the intensive care unit during 1997 to 1998. Seventeen of the 52 Acinetobacter baumannii (genomic DNA group 2) isolates from 1997 to 2000 harbored intI1, but only one was positive for these gene cassettes, whereas 20 of the 21 intI1-positive isolates of all other genomic DNA groups were positive for either or both of them. Reduced susceptibility to imipenem and rifampin was seen only in isolates harboring the bla(IMP-4) and arr-2 cassettes, respectively. The aminoglycoside phosphotransferase [APH(3')-VIa] gene aph(3')-VIa was detected in all 21 isolates for which the MIC of amikacin was >/=8 micro g/ml, with or without aacA4, whereas aacA4 alone was found in isolates for which the MIC of amikacin was 0.5 to 2 micro g/ml. Significant differences between the 17 intI1-positive and 47 intI1-negative isolates belonging to genomic DNA group 3 from 1997 to 1998 in the MICs of amikacin, gentamicin, imipenem, sulfamethoxazole, and ceftazidime were observed (Mann-Whitney test, P < 0.001 to 0.01).     

Molecular characterization of integrons in Acinetobacter baumannii: description of a hybrid class 2 integron

Twenty Acinetobacter baumannii strains resistant to various antibiotics were analyzed for integron content and sequences of the amplification products. Sixteen clinical isolates had a class 1 integron, 2 contained an additional class 1 or class 2 integron, but no class 3 integron was detected. Thirteen strains had integrons with a single cassette: aac(3)-Ia (9 strains), ant(2")-Ia (2 strains), or aac(6')-Ib (2 strains); 1 had aac(6')-Ib and oxa20 cassettes and an unknown gene; and 1 had an integron containing ant(2")-Ia and an oxa3 cassette truncated by IS6100. The remaining strains harbored class 1 integrons with gene cassettes previously found in Enterobacteriaceae. One integron had a hybrid structure composed of intI2 and the 3' conserved segment of class 1 integrons. These data indicate that integrons play a major role in multidrug resistance in Acinetobacter.     

耐亚胺培南鲍曼不动杆菌碳青霉烯酶及整合子分布

目的 了解耐亚胺培南鲍曼不动杆菌碳青霉烯酶及整合子分布情况.方法 收集天津医科大学总医院2008年1月至2010年3月期间,103株亚胺培南耐药鲍曼不动杆菌临床标本.用Vitek-2系统鉴定细菌,并进行药敏试验,通过改良Hodge试验、改良三维试验和2-巯基丙酸协同试验初筛碳青霉烯酶,多重PCR同时检测4种OXA型碳青霉烯酶基因、2种金属酶基因及整合酶基因,对整合子可变区进行PCR检测及序列分析.结果 103株鲍曼不动杆菌中,改良Hodge试验检出碳青霉烯酶阳性75株(72.8%),改良三维试验检出产碳青霉烯酶菌株80株(77.7%),未检出产金属酶菌株.PCR检出blaOXA-51-like+bsaOXA-23-like+int11基因84株,blaOxA-51-like+blaOXA-23-like阳性5株,blaOXA-51-like+intll阳性8株,blaOXA-51-like+blaOXA-24-like阳性2株,仅blaOXA-51-like阳性4株,blaOXA-58-like、金属酶基因(IMP-1、VIM-2)及Ⅱ类整合酶基因(intI2)均阴性.89株(96.7%)Ⅰ类整合酶阳性株均扩增出可变区,检出2种耐药基因盒组合形式:aacA4-catB8-aadAl(2 300 bp)81株,aacCl-orfX-orfX-orfX'-aadAla(3 000 bp)8株.结论 鲍曼不动杆菌对碳青霉烯类耐药及多重耐药主要与其携带的OXA-23型碳青霉烯酶和Ⅰ类整合子有关.

Abstract：

Objective To investigate the carbapenemases and integrons in imipenem-resistant Acinetobacter baumannii. Methods One hundred and three Acinetobacter baumannii were collected from Janurary 2008 to March 2010 in Tianjin Medical University General Hospital. The identification of strains and antimicrobial susceptibility test were performed by using Vitek-2 compact automatic system. Isolates of imipenem-resistant A. baumannii were screened for carbapenemases by modified Hodge test, improved threedimensional test and 2-mercaptopropionic acid synergy test. Isolates were then subjected to the multiplex PCR targeting genes encoding for OXA type carbapenemases, metallo-β-lactamases (MBLs) and integrases. The variable regions of integrons were amplificated and sequenced. Results Among the 103 isolates, 75 (72. 8% ) demonstrated positive in the modified Hodge test, 80 (77.7%)were positive in the improved three-dimensional test. No MBLs was found in the 2-mercaptopropionic acid synergy test. Eightyfour isolates were positive for blaOXA-51-like, blaOXA-23-like, and intI1; five were positive for blaOXA-51-like and blaOXA-23-like ;eight were positive for blaOXA-51-like and int11 ;two were positive for blaOXA-51-like and blaOXA-24-like ;four were only found positive for blaOXA-51-like. The blaOXA-58-like, IMP-1, VIM-2 and intI2 genes were all negative. Eighty-nine(96. 7% )of the intI1 positive strains owned the variable region. Two different cassettes arrangements were identified within class 1 integrons:81 isolates harbored aacA4-catB8-aadAI (2 300 bp) and 8 harbored aacCl-orX-orfX-orX'-aadAla (3 000 bp ) . Conclusion The presence of OXA-23 carbapenermase and class Ⅰ integrons are correlated with Acinetobacter baumannii resistant to carbapenems and multi-drug resistance.     

革兰阴性菌中整合子携带氨基糖苷类耐药基因的分布

目的研究湖南地区革兰阴性菌中整合子的流行现状及其携带的耐药基因的特点。方法收集183株革兰阴性菌,MIC法检测其药敏活性,利用不同的引物PCR筛查整合子的种类及整合子可变区,RFLP分析可变区,并测序确定其所携带的耐药基因盒内容。结果细菌均为多重耐药菌;整合子检出率为54.6%,均为Ⅰ类整合子;携带5种整合子可变区,分别是0.75 kb,1.0 kb,1.8 kb,2.0 kb,3.0 kb;可变区内容为intI1-dfr15-aadA2-qacE△1-ampR,dhfrⅫ-orfF-aadA2,aacA4-catB8-aadA1,dhrfⅫ-aadA2,intI1-dfrA12-aadA2-qacE△1-sul1-ISCR1-blaCTX-M-14-IS903。结论Ⅰ类整合子广泛分布于我院分离的革兰阴性菌中,广泛携带氨基糖苷类和磺胺类耐药基因。氨基糖苷类耐药基因盒的高频出现与抗生素选择性压力无关。     

Identification and characterization of class 1 integrons in bacteria from an aquatic environment.

In a survey of 3000 Gram-negative bacteria isolated from an estuarine environment over a 2 month period, the incidence of class 1 integrons was determined to be 3.6%. Of 85 integrons studied further, 11 lacked both the qacEdelta1 and sull genes usually present in the 3' conserved segment of the integron. The qacEdelta1 and sull genes were identified in the 3' conserved segment of 36 integrons. The remaining 38 integrons lacked a sull gene but contained a qacE gene. The variable region of 74 integrons was characterized by PCR and sequence analysis. Forty of the integrons were found to lack integrated gene cassettes, although 21 of these 'empty' integrons were shown to contain inserted DNA which has been tentatively identified as a novel insertion sequence (IS) element. Of the 34 integrons which contained inserted gene cassettes, the aadA1a gene was found to be the most prevalent (74%). Nineteen integrons contained additional or other gene cassettes in their variable region, including those encoding resistance to trimethoprim (dfr1a, dfrIIc, dfrV, dfrVII, dfrXII), chloramphenicol (catB3, catB5), aminoglycosides (aadA2, aacA4, aacC1), beta-lactamases (oxa2) and erythromycin (ereA). This study confirms the occurrence of integrons in bacteria from a natural habitat and suggests that in the absence of continued antibiotic selective pressures, integrons which persist appear to preferentially exist without integrated antibiotic resistance gene cassettes.     

多重耐药铜绿假单胞菌整合子中发现2种新基因盒组合形式

目的研究多重耐药铜绿假单胞菌携带整合子的类型及耐药基因组合。方法 PCR检测多重耐药铜绿假单胞菌整合酶基因intI 1、intI 2、intI 3,Ⅰ类整合子恒定区基因qacEΔ1-sul1及可变区基因,扩增产物经胶回收、限制性片段长度多态性(RFLP)分析及基因测序分析。结果 30株临床分离铜绿假单胞菌中16株(53.3%)Ⅰ类整合酶基因及恒定区qacEΔ1-sul1基因扩增阳性,未检出Ⅱ、Ⅲ类整合酶基因。Ⅰ类整合子可变区共检出5种不同的耐药基因组合形式,含有对氨基糖苷类、β-内酰胺类和喹诺酮类抗菌药耐药的基因,其中有2种为新型基因盒组合形式,包括aacA4-VIM2和aadA2-OXA10-aacA4-blaIMP-9-aatI1,GenBank登录号分别为GQ890658和GU122165,另外3种与GenBank登录号分别为FJ917747、FJ817423、GU367339的序列基本吻合。结论多重耐药铜绿假单胞菌携带的整合子主要为Ⅰ类整合子,在Ⅰ类整合子上首次发现2种新型基因盒组合形式。     

携带新型耐药基因盒组合形式Ⅰ类整合子的铜绿假单胞菌耐药特性分析

目的分析1株临床分离携有多重耐药基因盒整合子的铜绿假单胞菌的耐药特性。方法应用PCR-限制性片段长度多态性（PCR—RFLP）对整合子进行检测及分型，用长片段PCR（Long—PCR）扩增整合子的可变区并进行DNA测序，分析整合子可变区含有的耐药基因。同时应用PCR扩增金属酶基因和oprD2基因。结果该株铜绿假单胞菌PA27携带Ⅰ类整合子，其可变区大小为3.0kb，含有编码对氨基糖苷类、氯霉素和β内酰胺类抗生素耐药的基因，经与GenBank数据库进行同源性分析（BLAST），确定为一种新型基因盒组合形式：aac（6’）-Ⅱ-cm1A8-OXA-10，GenBank登录号为EU708817。oprD2基因检测阳性，未检出IMP-1、VIM-2和IMP-2型金属酶基因。结论该地区首次报道携带新型基因盒组合形式的Ⅰ类整合子的铜绿假单胞菌，并携有多重耐药基因，应引起临床高度重视。     

烟台地区嗜麦芽窄食单胞菌整合子分布及其可变区所携带耐药基因盒的研究

目的：分析嗜麦芽窄食单胞菌对临床常用抗菌药物的耐药性,探讨明确嗜麦芽窄食单胞菌Ⅰ、Ⅱ、Ⅲ类整合子的存在情况以及所携带的耐药基因盒,为本地区更好地预防和控制嗜麦芽窄食单胞菌感染性疾病提供帮助。方法收集临床分离的51株嗜麦芽窄食单胞菌采用微量肉汤稀释法测定嗜麦芽窄食单胞菌对17种抗菌药物的最低抑菌浓度（MIC）。根据 GenBank 注册的基因序列设计引物,PCR 扩增Ⅰ、Ⅱ、Ⅲ类整合子。对整合子阳性菌株扩增其可变区产物进行测序分析,所得结果在 GenBank数据库中进行同源性比对,了解可变区中含有基因盒的信息。结果（1）51株嗜麦芽窄食单胞菌标本来源分布以痰液最多,为41株,占80．39％,感染人群主要以60岁以上年龄段为主,为38株,占74．5％。病房分布：重症监护室（ICU）20株,占39．22％;呼吸内科13株,占25．49％;干部病房6株,占11．76％,所占比例较大。（2）药敏结果显示嗜麦芽窄食单胞菌对多数常用抗菌药物耐药性较高,部分菌株表现出对9种以上抗菌药物的多重耐药。（3）51株嗜麦芽窄食单胞菌 PCR 基因扩增结果7株菌Ⅰ类整合子阳性（13．7％）,没有检测到Ⅱ、Ⅲ类整合子,Ⅰ类整合子可变区携带的耐药基因包括 aacA4、aadA1、catB8、dfrA17和 aphA15五种。结论嗜麦芽窄食单胞菌对多数常用抗菌药物耐药性较高,部分菌株表现出多重耐药性。Ⅰ类整合子是嗜麦芽窄食单胞菌多重耐药的重要因素之一。