ICU耐亚胺培南铜绿假单胞菌的耐药性及危险因素分析

目的探讨重症监护病房(ICU)耐亚胺培南铜绿假单胞菌(IRPA)耐药性以及感染的危险因素。方法对ICU临床分离的铜绿假单胞菌标本,采用标准纸片扩散法进行药敏试验。用PCR法检测外膜孔蛋白OprD2基因、金属β-内酰胺酶(MBL)IMP、VIM、GIM和SPM耐药基因和Ⅰ类整合子,并回顾性分析引起IRPA感染的危险因素。结果共检出60株铜绿假单胞菌,其中对亚胺培南敏感20株,耐亚胺培南40株,其中OprD2基因缺失36株,是耐亚胺培南的主要原因。产MBL 4株,Ⅰ类整合子阳性36株。单因素分析发现患者住院时间>2周、气管插管(或切开)、机械通气以及2周内接受过碳青酶烯类抗生素治疗与IRPA感染有关。结论 ICU IRPA的耐药率维持较高水平,OprD2基因缺失及其产MBL是细菌对亚胺培南抗菌药物耐药的重要机制,对IRPA感染应以预防为主,建立耐药监控体系,控制耐药的发展。     

铜绿假单胞菌耐药情况和携带耐药基因分析

目的：分析铜绿假单胞菌（ PA）的耐药情况和携带耐药基因的情况。方法选择2012年6-12月在我院不同来源的50株PA,收集其药敏结果统计分析耐药情况,并用PCR方法检测其携带耐药基因的情况。结果50株细菌中检出7株有TEM基因,6株有OXA-10基因,4株外膜孔蛋白基因OprD2缺失。50株PA菌株对药物的耐药率情况为：亚胺培南6．00％,美罗培南6．52％,多黏菌素7．89％,哌拉西林／他唑巴坦10．42％,左旋氧氟沙星12．77％,阿米卡星14％,环丙沙星14．29％,头孢他啶26．00％,头孢吡肟28．57％,哌拉西林29．55％,庆大霉素30．00％,氨曲南38．00％。结论50株PA菌株中,耐亚胺培南可能是因为OprD2蛋白表达缺失,但并非所有的OprD2缺失均导致亚胺培南耐药。携带TEM和（或） OXA-10基因则可能耐β内酰胺类抗菌药。     

一株耐亚胺培南肺炎克雷伯菌耐药的分子机制探讨

目的研究肺炎克雷伯菌(KP)对亚胺培南耐药的分子机制。方法用KB法对KP进行常规药敏试验,选取该株对亚胺培南耐药的KP,并用PCR扩增方法检测其耐药基因:TEM、SHV、PER、VEB、CARB、VIM、IMP、GIM、SPM、DHA、GES、OXA、aac(6′)-Ⅰ、aac(6′)-Ⅱ、ant(3′)-Ⅰ、ant(2″)-Ⅰ、qacE△1-sulⅠ、int-Ⅰ、CTX-M、acc(3′)-Ⅱ、KPC。结果耐药基因TEM、DHA、aac(6′)-Ⅰ、ant(3″)-Ⅰ、qacE△1-sulⅠ为阳性,其他耐药基因均为阴性。结论该菌对亚胺培南耐药并非KPC所致,主要是TEM、DHA型β-内酰胺酶合并其他原因共同作用所致。     

ICU病房29株铜绿假单胞菌的耐药表型及基因型分析

目的探讨ICU铜绿假单胞菌(PA)耐药表型及基因型特征。方法采用K-B法测定29株PA对15种抗生素的药敏结果。用PCR检测21种耐药基因,分析从ICU分离的29株PA的耐药表型及其基因型。结果 29株PA对15种抗生素的耐药率都较高。其中,对比阿培南、左氧氟沙星、环丙沙星的耐药率分别为27.59%、51.72%、55.17%,对其他常用抗生素的耐药率均在60.00%以上。29株PA耐药基因阳性率较高的有aac(6′)-Ⅱ、ant(3″)-Ⅰ、qacE△1-sul1及intⅠ1,阳性率分别为79.31%、72.41%、75.86%及51.72%。结论该组PA携带多种耐药基因;其耐药主要与Ⅰ类整合子、aac(6′)-Ⅱ、ant(3″)-Ⅰ有关。     

亚胺培南耐药铜绿假单胞菌消毒剂及β内酰胺类抗生素耐药相关基因研究

目的 了解临床分离的对亚胺培南耐药的铜绿假单胞菌消毒剂及G内酰胺类抗生素耐药相关基因存在状况。方法 自临床分离28株对亚胺培南耐药铜绿假单胞菌,采用聚合酶链反应(PCR)及序列分析的方法检测耐药基因。结果28株中,qacE△1、TEM、OXA基因阳性株数(％)分别为24株(85．7％)、20株(71．4％)、1株(3．6％),此株0XA基因经序列分析确认为OXA-10型超广谱β内酰胺酶(GenBank注册号：AY841859)。25株(89．3％)oprD基因缺失,IMP、V1M、SHV、PER、VEB、GES、MIR、DHA基因均阴性。结论临床分离的对亚胺培南耐药的铜绿假单胞菌耐消毒剂基因qacEA1及TEM基因携带率均很高,至少存在TEM、OXA-10两种β内酰胺酶基因,oprD基因缺失突变是对亚胺培南耐药的重要原因。     

铜绿假单胞菌“泛耐株”耐药相关基因研究

目的 研究"泛耐"铜绿假单胞菌中多种耐药基因的存在情况及耐药机制.方法 采用聚合酶链反应(PCR)法检测22株"泛耐"铜绿假单胞菌的β-内酰胺酶基因、氨基糖苷类修饰酶(AMEs)基因、喹诺酮类耐药基因、耐消毒剂基因(qacE△l-sull)和整合酶基因.结果 PCR扩增结果显示22株菌中oprD2、blaCAEB、gyrA、aac(6')-Ⅰb、ant(2")-Ⅰ和qacE △ J-sull基因均阳性;blaSHV、blaSPM、blaGIM、blaDHA、blaOXA-10、blaGES、blaPER、aac(3')-Ⅰ和aac(6')-Ⅱ基因均阴性;blaIMP、blaTEM、blaVEB、aac(3')-Ⅱ、ant(3")-Ⅰ、int Ⅰ1和blaVIM阳性率分别为95.5%、77.3%、13.6%、4.5%、4.5%、4.5%和4.5%.结论 oprD2基因阳性说明这些泛耐菌株中外膜蛋白并未缺失,多种耐药基因同时存在是本研究中铜绿假单胞菌"泛耐"的根本原因.     

耐亚胺培南铜绿假单胞菌对β-内酰胺类抗菌药物耐药相关基因的研究

目的:研究耐亚胺培南铜绿假单胞菌(IMPRPa)β-内酰胺类抗菌药物耐药相关基因的存在情况。方法:对60株临床分离的IMPRPa,采用聚合酶链(PCR)方法检测β-内酰胺类抗菌药物耐药相关基因IMP、VIM、OprD2,并对部分IMP、VIM基因的PCR扩增产物进行序列分析。结果:60株受试菌中,β-内酰胺类抗菌药物耐药相关基因检测阳性为:IMP7株,VIM18株,有3株菌同时携带IMP、VIM基因,IMP、VIM基因序列分析为IMP-1型和VIM-2型,OprD2基因缺失29株。结论:OprD2蛋白通道缺失和产金属β-内酰胺酶是IMPRPa耐亚胺培南的主要机制。     

耐亚胺培南铜绿假单胞茵的耐药机制研究

目的 对临床分离的14株耐亚胺培南铜绿假单胞菌的耐药机制进行研究.方法药敏试验检测对15种常用抗菌药物的耐药情况;协同试验筛选产金属酶菌株和聚合酶链反应检测金属酶基因及oprD基因;氰氯苯腙检测主动外排情况及其对亚胺培南最低抑菌浓度(MIC)的影响.结果耐亚胺培南的铜绿假单胞菌对其它常用抗菌药物耐药率也很高,其中,5株产VIM-2型金属酶,11株oprD基因检测阴性.2株在有氰氯苯腙存在时对亚胺培南的MIC降低至原值的1/4,表明这2株有主动外排系统参与对亚胺培南的耐药.结论 OprD2蛋白表达缺失是本研究中铜绿假单胞菌对亚胺培南耐药的主要原因,其次为产VIM-2型金属酶和主动外排系统,且至少有4株存在两种以上耐亚胺培南的机制.     

呼吸道分泌物铜绿假单胞菌的耐药性研究

目的了解呼吸道感染铜绿假单胞菌PA的耐药性变化,指导临床合理使用抗生素。方法用autoscan-4细菌鉴定仪对166株PA进行菌种鉴定、药敏试验及诱导型β-内酰胺酶(IB)检测,统计耐药率,做统计学分析。结果PA产酶率为89.2%;哌拉西林/三唑巴坦、头孢他啶、阿米卡星、环丙沙星、亚胺培南、安曲南、哌拉西林、头孢曲松和庆大霉素等抗生素耐药率较低,为15.1%～45.8%。产IB株对阿米卡星、安曲南、头孢唑肟和头孢曲松等的耐药性与不产IB株相比无显著性差异(P>0.05),其余均有显著性差异(P<0.01)。结论PA产IB株呼吸道感染严重,因此加强耐药性监测,根据分离株的耐药特点合理用药非常重要。     

耐头孢菌株的糖尿病肾病临床特点的研究

目的 研究耐头孢他啶的糖尿病肾病患者对β-内酰胺酶(EsBIJs)携带情况及对常用抗菌药物的耐药情况.方法 筛选出耐头孢他啶的菌株,PCR扩增基因TEM、SHV、CTX-M.进而进行对头孢他啶、庆大霉素、环丙杀星、头孢西丁、头孢哌酮/ 舒巴坦和亚胺培南的药敏性检验.结果 有89%糖尿病肾病患者出现耐头孢他啶的情况,在耐头孢他啶菌株中有68%表现产ESBLs 阳性菌对头孢类抗生素高度耐药,对庆大霉素、环丙杀星的耐药率为69%～88%,对头孢西丁、头孢哌酮/ 舒巴坦耐药率为20%～30%,对亚胺培南高度敏感(100%).结论 耐头孢他啶的糖尿病肾病患者易携带β-内酰胺酶基因,并表现多重耐药性.     

Antimicrobial susceptibility of Pseudomonas aeruginosa isolated in Fukushima Prefecture

We investigated the susceptibility of Pseudomonas aeruginosa (isolated from the sputum of patients with respiratory infection in 4 medical institutions in Fukushima Prefecture) to 8 beta-lactam antibiotics including three carbapenems and relationships among MICs of antibiotics tested. The MIC90 values for a total of 216 strains were 6.25 micrograms/ml for meropenem, 12.5 micrograms/ml for imipenem and ceftazidime, 25 micrograms/ml for panipenem and cefsulodin, 50 micrograms/ml for cefpirome and over than 200 micrograms/ml for cefoperazone and piperacillin. The frequency of resistance of these strains to each antibiotic was as follows: The resistant strains were 19 (8.8%) for meropenem, 34 (15.7%) for imipenem and ceftazidime, 50 (23.1%) for cefsulodin, 72 (33.3%) for panipenem, 76 (35.2%) for piperacillin and 90 (41.7%) for cefpirome. Eighteen strains (18.3%) of 19 meropenem resitant straisn were resistant to imipenem and panipenem, but 16 strains of the 34 imipenem-resistant strains and 54 strains of the 72 panipenem-resistant strains were susceptible to meropenem. In investigation of isolation of multi-resistant Pseudomonas aeruginosa, the susceptibility of strains tested to 7 antibiotics except cefoperazone was as follows: The strains susceptible to all the 7 antibiotics were 92 strains (42.6%), and 33 strains (15.2%) were resistant to 2 antibiotics, 31 strains (14.4%) were resistant to 1 antibiotic, 21 strains (9.7%) were resistant to 3 antibiotics, 13 strains (6.0%) were resistant to 5 antibiotics, 9 (4.2%) were resistant to 4 and 7 antibiotics, and 8 strains (3.7%) were reistant to 6 antibiotics. Since the emergence of these multi-resistant strains is closely related to frequent use of antibiotics for nosocomial infections, special attention should be paid to the antimicrobial susceptibility of Pseudomonas aeruginosa and the situation of antibiotic resistant strains.     

耐碳青霉烯酶铜绿假单胞菌外膜蛋白OprD2基因型的研究

目的分析耐亚胺培南铜绿假单胞菌携带耐药基因,为临床合理选用抗菌药物提供依据,为降低细菌的耐药性和控制医院感染提供参考依据。方法收集临床标本分离出的耐亚胺培南铜绿假单胞菌的耐药性;聚合酶链式反应(PCR)检测碳青霉烯类相关基因及外膜蛋白基因OprD2的携带情况。结果 PCR法检测出携带OprD2基因5株(33.3%);携带blaVIM基因4株(26.7%);携带blaOXA-10基因8株(53.3%)。blaGES、blaIMP、blaGIM、blzSIM、blaTEM、blaPER、blaVEB基因均未检出。结论铜绿假单胞菌感染以上呼吸道为主,其耐药性高,应规范临床用药,加强铜绿假单胞菌耐药性监测,有效控制院内感染。     

Pseudomonas aeruginosa infections in the Intensive Care Unit: can the adequacy of empirical beta-lactam antibiotic therapy be improved?

Inadequate empirical antibiotic therapy for serious Pseudomonas aeruginosa infections has been linked to increased mortality. We performed a retrospective cohort study of consecutive patients with ventilator-associated pneumonia, bacteraemia or other sterile-site infections caused by P. aeruginosa occurring during Intensive Care Unit admissions. One hundred and fifty-eight episodes of serious infection with P. aeruginosa occurred in 140 patients. Empirical antibiotic therapy was microbiologically adequate in 67% of episodes of infection. Patients with P. aeruginosa isolates resistant to piperacillin/tazobactam or cefepime were more likely to have received these antibiotics in the month prior to the P. aeruginosa infection or to have had a Gram-negative bacillus resistant to these antibiotics isolated in the month prior to the P. aeruginosa infection. From these data, we have developed simple algorithms for empirical antibiotic choice in seriously ill patients with suspected P. aeruginosa infections based on prior antibiotic exposure and prior isolation of antibiotic-resistant organisms. Application of these algorithms would have improved the adequacy of empirical antibiotic therapy from 67% to 80-84%. Routine empirical addition of amikacin to the beta-lactam would have increased the adequacy of the antibiotics to 96%. We conclude that knowledge of the prior receipt of beta-lactam antibiotics with activity against P. aeruginosa and the isolation of Gram-negative bacilli resistant to such antibiotics in the recent past can readily increase the adequacy of empirical antibiotic therapy for suspected P. aeruginosa infections.     

铜绿假单胞菌对亚胺培南的耐药性分析及机制探讨

目的:研究铜绿假单胞菌对亚胺培南的耐药性及其机制。方法:取痰液中培养分离的铜绿假单胞菌55株,经K-B法检测耐药性。采用外膜蛋白图谱,对其外膜蛋白OprD2进行SDS-PAGE分析,双纸片增效法检测金属β-内酰胺酶。结果:根据耐药性分为铜绿假单胞菌亚胺培南菌耐药36株和敏感19株。铜绿假单胞菌亚胺培南耐药株不同程度OprD2减少,耐药组OprD2相对含量明显低于敏感组(P<0.01);产金属β-内酰胺酶6株,检出率10.9%。结论:OprD2的减少和产金属β-内酰胺酶是铜绿假单胞菌对亚胺培南耐药的主要原因。     

鲍曼不动杆菌Ⅰ类整合子与多重耐药相关性研究

目的 了解临床分离鲍曼不动杆菌的耐药状况、Ⅰ类整合子的分布情况,探讨Ⅰ类整合子与多重耐药的关系.方法 检测20种临床常用抗菌药物对鲍曼不动杆菌临床分离株的最低抑菌浓度(MIC).PCR扩增Ⅰ类整合酶基因.对部分Ⅰ类整合酶阳性菌株进行耐药基因盒序列分析.结果 鲍曼不动杆菌呈现多重耐药,鲍曼不动杆菌对IMP和MRP耐药率分别为0.9%和1.8%,对CPZ/SB的耐药率为35.7%,对其它抗菌药物的耐药率均大于60%,多重耐药率为76.8%(86/112),但对COL和MIN均敏感.80.4%(90/112)的菌株检测出Ⅰ类整合子.Ⅰ类整合子阳性株对多种药物的耐药率均高于阴性株,且Ⅰ类整合子阳性株多重耐药率(90%)明显高于阴性株(22.7%)(P<0.01).Ⅰ类整合子基因盒序列分析显示,Ⅰ类整合子携带aacA4,catB8和aadA13种耐药基因.结论 Ⅰ类整合子在鲍曼不动杆菌中检出率很高并与其多重耐药性关系密切.     

Antibacterial activity of aztreonam: a synthetic monobactam. A comparative study with thirteen other antibiotics

The in vitro activity of aztreoman (SQ 26, 776), a new monocyclic beta-lactam antimicrobial agent, was determined against 1720 bacteria, all clinical isolates, and compared with that of thirteen beta-lactam and aminoglycoside antibiotics. Aztreonam inhibited 90% of Citrobacter diversus, Citrobacter freundii, Enterobacter agglomerans, E. coli, Klebsiella pneumoniae, Proteus mirabilis, Proteus morganii, Proteus rettgeri, Proteus vulgaris and Salmonella sp. by less than or equal to 0.4 micrograms ml-1. This activity was superior to moxalactam, piperacillin, cefamandole, cefoperazone, cefoxitin, cefsulodin, ceftazidime and aminoglycoside antibiotics. Aztreonam was as active as moxalactam against Enterobacter aerogenes, Enterobacter cloacae and Shigella species. Pseudomonas aeruginosa strains resistant to moxalactam, piperacillin, cefamandole, cefoperazone, cefotaxime, cefoxitin, cefsulodin and ceftazidime were inhibited by aztreonam 50% by 6.3 micrograms ml-1 and 90% by 16 micrograms ml-1. Aztreonam was as active as ceftazidime against Serratia marcescens, all strains were inhibited by 3.1 micrograms ml-1 and 90% by 1.6 micrograms ml-1. There was no major difference between MBC and MIC values of aztreonam and the effect of inoculum size upon MIC values was observed at 10(7) CFU.     

Evaluation of genetic determinants involved in beta-lactam- and multiresistance in a surgical ICU

Antibiotic resistance is a major and well-known problem in intensive care units (ICUs) world-wide and previously susceptible isolates become resistant through the acquisition of resistance determinants from other bacteria or the development of mutations, as is the case in beta-lactam resistance. We evaluated the presence of resistance determinants involved in beta-lactam resistance and multi-resistance in order to establish the contribution of horizontal gene transfer to the spread of resistance in a surgical ICU during an antibiotic rotation study. Pseudomonas aeruginosa and Enterobacteriaceae isolates were selected and iso-electric focusing (IEF), DNA-typing methods such as specific beta-lactamase and specific integron PCRs were performed to determine the presence of beta-lactamases. The PCRs specific for IMP-1, OXA-1, and VIM-type beta-lactamases performed on the selected P. aeruginosa and Enterobacteriaceae isolates with MICs for cephalosporins >1 mg/l did not demonstrate any of these beta-lactamases. IEF for 14 pseudomonads, representing 7 genotypes from 9 patients, showed a beta-lactamase with a pI larger than 8.5 in 13 of the isolates. The integrase PCR was positive for only five isolates from three patients and conserved segment PCR showed integrons of variable sizes (700, 900, 1,400 and 1,500 bp). Each patient had its own integron types. It can be concluded that integrons and associated resistance determinants played only a minor role in the surgical ICU and beta-lactam resistance among P. aeruginosa isolates was most likely due to the derepression of its AmpC gene.     

铜绿假单胞菌I类整合子相关基因的解析和定位

目的对4株铜绿假单胞菌临床菌株携带的I类整合子相关基因进行解析和定位，探讨I类整合子相关基因在细菌耐药性形成和耐药基因播散中的作用。方法采用PCR扩增、DNA测序、DNA序列比对的方法对4株铜绿假单胞菌临床菌株携带的I类整合子相关基因进行解析，采用接合试验对该类整合子进行定位分析。结果4株铜绿假单胞菌I类整合子都含有耐药基因．该耐药基因在相应菌株中发挥耐药作用；该菌整合子位于质粒上。结论I类整合子耐药基因在铜绿假单胞菌耐药性形成和耐药基因的播散中发挥作用。