• 【美罗培南,大肠菌素和替加环素的三重组合在动态模型中具有杀菌作用,尽管在棋盘试验中仅对产生碳青霉烯酶的肺炎克雷伯菌分离株进行了加性相互作用。】 复制标题 收藏 收藏
    DOI:10.1093/jac/dky422 复制DOI
    作者列表:Tsala M,Vourli S,Georgiou PC,Pournaras S,Daikos GRL,Mouton JW,Meletiadis J
    BACKGROUND & AIMS: Background:Combination schemes are commonly used for the treatment of infections due to carbapenemase-producing Klebsiella pneumoniae (CP-Kp). We therefore investigated the in vitro effectiveness of double and triple combinations of meropenem, colistin and tigecycline against CP-Kp isolates with different resistance mechanisms in a static broth microdilution model and a pharmacokinetic-pharmacodynamic model. Methods:One WT isolate and seven CP-Kp isolates with different carbapenem resistance mechanisms and increasing MICs of meropenem (4-512 mg/L), colistin (0.5-32 mg/L) and tigecycline (0.25-4 mg/L) were tested with a 3D chequerboard microdilution method. Combinations were then assessed in an in vitro pharmacokinetic-pharmacodynamic model simulating 50 and 100 mg of tigecycline q12h as a 1 h infusion, 4.5 million units of colistin q12h as a 1 h infusion and 1 g of meropenem q8h as 1 and 0.5 h infusions for 2 days. Results:In the chequerboard assay, interactions within the triple combination were mainly additive with a median (range) fractional inhibitory index of 0.66 (0.22-1.26). In the dynamic model, meropenem alone was bactericidal against isolates with MICs up to 4 mg/L, whereas bactericidal activity was found with the double combination meropenem + colistin and the triple combination meropenem + colistin + tigecycline against CP-Kp isolates with meropenem MICs of 16 and 256 mg/L, respectively. A high dose (100 mg) of tigecycline and a prolonged infusion (1 h) of meropenem increased the efficacy of the triple combination. Conclusions:Despite the merely additive interactions in the chequerboard assay, the triple combination of meropenem, tigecycline and colistin was bactericidal in the dynamic model against highly resistant CP-Kp isolates. This effect was more pronounced if prolonged infusion of meropenem and high tigecycline dosing were used.
    背景与目标: 背景:联合方案通常用于治疗因产生碳青霉烯酶的肺炎克雷伯菌(CP-Kp)引起的感染。因此,我们在静态肉汤微稀释模型和药代动力学-药效学模型中研究了美罗培南,大肠菌素和替加环素的双重和三重组合对具有不同耐药机制的CP-Kp分离株的体外有效性。
    方法:选择1个WT分离株和7个CP-Kp分离株,它们具有不同的碳青霉烯耐药机制,并具有美罗培南(4-512 mg / L),粘菌素(0.5-32 mg / L)和替加环素(0.25-4 mg / L)的MIC增加。使用3D棋盘格微量稀释方法进行了测试。然后在体外药代动力学-药效学模型中评估组合,模拟50mg / 100mg的替加环素q12h的剂量为1µh输注,450万单位的粘菌素q12h的剂量为1µh输注,以及1µg美罗培南的q8h剂量为1µh和0.5µh输注。 2天。
    结果:在棋盘实验中,三重组合内的相互作用主要是累加的,中位(范围)分数抑制指数为0.66(0.22-1.26)。在动态模型中,单独的美罗培南对具有高达4 mg / L MIC的分离株具有杀菌作用,而美罗培南大肠粘菌素的双重组合和美罗培南大黄素三联素tigecycline的三联组合对美罗培南MIC分别为16和256的CP-Kp分离株具有杀菌活性。分别为mg / L。高剂量(100μmg)的替加环素和长时间输注(1μh)的美洛培南可提高三联组合的疗效。
    结论:尽管在棋盘实验中仅存在加性相互作用,但美罗培南,替加环素和粘菌素的三重组合在动态模型中对高抗性CP-Kp分离株具有杀菌作用。如果长期输注美洛培南和使用高剂量的替加环素,则这种作用更为明显。
  • 【菲律宾医院污水和河水中产生碳青霉烯酶的肠杆菌科的环境存在和遗传特征。】 复制标题 收藏 收藏
    DOI:10.1128/AEM.01906-19 复制DOI
    作者列表:Suzuki Y,Nazareno PJ,Nakano R,Mondoy M,Nakano A,Bugayong MP,Bilar J,Perez M 5th,Medina EJ,Saito-Obata M,Saito M,Nakashima K,Oshitani H,Yano H
    BACKGROUND & AIMS: :This study aimed to evaluate the prevalence and genetic characteristics of carbapenemase-producing Enterobacteriaceae (CPE) in hospital sewage and river water in the Philippines, which has a typical tropical maritime climate. We collected 83 water samples from 7 hospital sewage and 10 river water sites. CPE were identified using CHROMagar mSuperCARBA, and Gram-negative strains were identified using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) or 16S rRNA gene sequencing. Resistance genes in Enterobacteriaceae strains were identified using PCR and DNA sequencing, and transferability of carbapenemase genes from the CPE was investigated with conjugation experiments. Genotyping was performed using multilocus sequence typing (MLST) for Escherichia coli and Klebsiella pneumoniae Out of 124 Enterobacteriaceae isolates, we identified 51 strains as CPE and divided these into 7 species, 11 E. coli, 14 Klebsiella spp., 15 Enterobacter spp., and 11 others, including 4 additional species. Conjugation experiments via broth mating and using E. coli J53 revealed that 24 isolates can transfer carbapenemase-encoding plasmids. MLST analysis showed that 6 of 11 E. coli isolates belonged to clonal complex 10 (CC10). Of 11 K. pneumoniae strains, 9 unique sequence types (STs) were identified, including ST147. Five types of carbapenemase genes were identified, with the most prevalent being NDM (n = 39), which is epidemic in clinical settings in the Philippines. E. coli CC10 and K. pneumoniae ST147, which are often detected in clinical settings, were the dominant strains. In summary, our results indicate that hospital sewage and river water are contaminated by CPE strains belonging to clinically important clonal groups.IMPORTANCE Carbapenemase-producing Enterobacteriaceae (CPE) cause severe health care-associated infections, and their increasing prevalence is a serious concern. Recently, natural ecosystems have been recognized as important reservoirs of antibiotic resistance genes. We investigated the prevalence and genetic characteristics of CPE isolated from the environment (hospital sewage and river water) in the Philippines and found several CPE, including Escherichia coli and other species, with different carbapenemases. The most prevalent carbapenemase gene type was NDM, which is endemic in clinical settings. This study revealed that isolates belonging to carbapenemase-producing E. coli CC10 and K. pneumoniae sequence type 147 (ST147), which are often detected in clinical settings, were dominant in the natural environment. Our work here provides a report on the presence and characteristics of CPE in the environment in the Philippines and demonstrates that both hospital sewage and river water are contaminated by CPE strains belonging to clinically important clonal groups.
    背景与目标: :这项研究旨在评估菲律宾的医院污水和河水中产生碳青霉烯酶的肠杆菌科(CPE)的流行和遗传特征,菲律宾是典型的热带海洋性气候。我们从7个医院污水和10个河水站点收集了83个水样。使用CHROMagar mSuperCARBA鉴定CPE,并使用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)或16S rRNA基因测序鉴定革兰氏阴性菌株。利用PCR和DNA测序鉴定肠杆菌科细菌的抗性基因,并通过缀合实验研究了来自CPE的碳青霉烯酶基因的可转移性。使用多基因座序列分型(MLST)对大肠杆菌和肺炎克雷伯菌进行基因分型,从124株肠杆菌科细菌中分离出51株CPE,并将其分为7种,分别为11种大肠杆菌,14种克雷伯菌,15种肠杆菌,其他11种,包括另外4种。通过肉汤交配和使用大肠杆菌J53进行的缀合实验表明,有24种分离株可以转移编码碳青霉烯酶的质粒。 MLST分析显示11株大肠杆菌中有6株属于克隆复合物10(CC10)。在11株肺炎克雷伯菌中,鉴定出9种独特的序列类型(ST),包括ST147。鉴定出五种碳青霉烯酶基因,其中最流行的是NDM(n = 39),这在菲律宾的临床环境中很流行。在临床环境中经常检测到的大肠杆菌CC10和肺炎克雷伯菌ST147是主要菌株。总而言之,我们的结果表明,医院污水和河水被属于临床上重要的克隆群体的CPE菌株污染。近来,自然生态系统已被认为是抗生素抗性基因的重要储存库。我们调查了菲律宾从环境(医院污水和河水)中分离出的CPE的流行和遗传特征,发现了几种CPE,包括大肠杆菌和其他物种,具有不同的碳青霉烯酶。最流行的碳青霉烯酶基因类型是NDM,在临床环境中很流行。这项研究表明,在临床环境中经常发现属于产碳青霉烯酶的大肠杆菌CC10和肺炎克雷伯菌序列类型147(ST147)的分离株。我们在这里的工作提供了有关菲律宾环境中CPE的存在和特征的报告,并证明了医院污水和河水均被临床上重要的克隆组的CPE菌株污染。
  • 【使用eazyplex SuperBug CRE系统在临床大肠杆菌分离物中快速检测编码广谱β-内酰胺酶和碳青霉烯酶的基因。】 复制标题 收藏 收藏
    DOI:10.1089/mdr.2019.0311 复制DOI
    作者列表:Zalas-Więcek P,Gospodarek-Komkowska E,Smalczewska A
    BACKGROUND & AIMS: : Objectives: This study evaluated the diagnostic performance of the eazyplex® SuperBug CRE (eSBCRE) system, based on a loop-mediated isothermal amplification (LAMP), for the detection of the most common extended-spectrum beta-lactamases (ESBL) and carbapenemase genes in 140 clinical isolates of Escherichia coli. Materials and Methods: ESBL (blaCTX-M-1group and blaCTX-M-9group) and carbapenemase (blaKPC, blaVIM, blaNDM, blaOXA-48, and blaOXA-181) genes were detected using the eSBCRE test and compared with the results obtained by PCR, real-time PCR, and phenotypic methods. Results: Concordant results of 100% between PCR/real-time PCR and eSBCRE assays were observed. Two of 140 E. coli isolates were positive for both ESBL and carbapenemase genes according to eSBCRE, PCR, and real-time PCR assays, whereas they were negative in double-disk synergy test. Of 16 E. coli isolates suspected of producing carbapenemase, 9 were positive for 48-oxacillinases (OXA-48) by 30 μg temocillin test, whereas the blaOXA-48 was found only in 1 E. coli isolate by all molecular methods. Maximum threshold time values (minutes:seconds) in the eSBCRE test were 6:00, 11:15, 11:00, and 9:00 for the blaCTX-M-1group, blaCTX-M-9group, blaVIM, and blaOXA-48 genes, respectively. Conclusions: The eSBCRE test based on LAMP method is a reliable, easy-to-use, and timesaving molecular system, which can be successfully used in the routine diagnostic for the rapid detection of the most common ESBL and carbapenemase genes among clinical E. coli isolates.
    背景与目标:
    目标:
    这项研究基于回路介导的等温扩增(LAMP),评估了eazyplex®SuperBug CRE(eSBCRE)系统的诊断性能,以检测140种最常见的广谱β-内酰胺酶(ESBL)和碳青霉烯酶基因大肠杆菌的临床分离株。
    材料和方法:
    使用eSBCRE测试检测了ESBL(blaCTX-M-1组和blaCTX-M-9组)和碳青霉烯酶(blaKPC,blaVIM,blaNDM,blaOXA-48和blaOXA-181)基因,并将其与PCR结果进行了比较,时间PCR和表型方法。
    结果:
    观察到PCR /实时PCR和eSBCRE分析之间100%的一致结果。根据eSBCRE,PCR和实时PCR分析,在140株大肠杆菌中,有2株ESBL和碳青霉烯酶基因均为阳性,而在双盘协同试验中则为阴性。在30μg替莫西林试验中,在怀疑产生碳青霉烯酶的16株大肠杆菌中,有9株对48-氧杂环菌酶(OXA-48)呈阳性,而通过所有分子方法仅在1株大肠杆菌中发现了blaOXA-48。对于blaCTX-M-1组,blaCTX-M-9组,blaVIM和blaOXA-48,eSBCRE测试中的最大阈值时间值(分钟:秒)为6:00、11:15、11:00和9:00。基因分别。
    结论:
    基于LAMP方法的eSBCRE测试是可靠,易于使用且省时的分子系统,可成功用于常规诊断中,以快速检测临床大肠杆菌分离物中最常见的ESBL和碳青霉烯酶基因。
  • 【高效液相色谱-质谱联用法检测肠杆菌中肺炎克雷伯菌肺炎克雷伯菌的方法。】 复制标题 收藏 收藏
    DOI:10.1007/s42770-019-00222-y 复制DOI
    作者列表:Lovison OA,Rau RB,Lima-Morales D,Almeida EK,Crispim MN,Barreto F,Barth AL,Martins AF
    BACKGROUND & AIMS: :Carbapenem-resistant Enterobacterales (CREs) have been recognized as an important threat to global health. CRE cause the majority of the difficult-to-treat infections in health-care settings and are associated with high mortality. Klebsiella pneumoniae carbapenemase (KPC)-producing CREs, in particular Klebsiella pneumoniae, are globally disseminated and responsible for a large number of outbreaks. Development of rapid methods for KPC detection can provide great clinical and epidemiological benefits to prevent KPC dissemination. The aim of this study was to standardize and validate a LC-MS/MS method to detect KPC. This method was also tested against a broad variety of species, including CRE with other carbapenemase genes and the recently reported mcr-1. For validation, 111 isolates with reduced susceptibility to carbapenems were selected (49 KPC-positive and 62 KPC-negative). The presence of four tryptic peptides related to the KPC enzyme was evaluated, and the identification of at least two of them classified the isolate as "KPC-positive." The LTLGSALAAPQR and LALEGLGVNGQ peptides were both detected in 47 of 49 isolates with the blaKPC gene. The other two peptides, GFLAAAVLAR and APIVLAVYTR, were detected in 46 and 19 isolates with the blaKPC gene, respectively. The method correctly classified 47 of 49 KPC-positive and all KPC-negative isolates yielding 96.07% of sensitivity and 100% of specificity. In conclusion, our results demonstrate that the KPC peptide markers were robustly detected by the method which presented high sensitivity and full specificity and therefore can be used as a reliable method to identify this resistance mechanism.
    背景与目标: :耐碳青霉烯的肠杆菌(CRE)被认为是对全球健康的重要威胁。在医疗机构中,CRE导致大多数难以治疗的感染,并与高死亡率相关。产生肺炎克雷伯菌的碳青霉烯酶(KPC),特别是肺炎克雷伯菌,在全球传播,并导致大量爆发。快速检测KPC的方法的开发可以提供巨大的临床和流行病学益处,以防止KPC传播。这项研究的目的是标准化和验证检测KPC的LC-MS / MS方法。还针对多种物种测试了该方法,包括带有其他碳青霉烯酶基因的CRE和最近报道的mcr-1。为了进行验证,选择了对碳青霉烯敏感性降低的111个分离株(49 KPC阳性和62 KPC阴性)。评估了与KPC酶有关的四种胰蛋白酶肽的存在,并且鉴定出其中至少两种将分离物归类为“ KPC阳性”。 LTLGSALAAPQR和LALEGLGVNGQ肽均在blaKPC基因的49个分离株中的47个中检测到。另外两个肽GFLAAAVLAR和APIVLAVYTR,分别在blaKPC基因的46个和19个分离物中检测到。该方法正确分类了49个KPC阳性分离株和所有KPC阴性分离株中的47个,可产生96.07%的敏感性和100%的特异性。总之,我们的结果表明,该方法能可靠地检测KPC肽标记物,具有较高的灵敏度和全特异性,因此可作为鉴定该耐药机制的可靠方法。
  • 【产生碳青霉烯酶的肠杆菌科的家庭传播:一项前瞻性队列研究。】 复制标题 收藏 收藏
    DOI:10.1093/jac/dkaa561 复制DOI
    作者列表:Marimuthu K,Mo Y,Ling ML,Hernandez-Koutoucheva A,Fenlon SN,Bertrand D,Lye DC,Ang BSP,Perencevich E,Ng OT,Cooper BS,Nagarajan N,Chen SL,Barkham T
    BACKGROUND & AIMS: OBJECTIVES:To estimate the transmission rate of carbapenemase-producing Enterobacteriaceae (CPE) in households with recently hospitalized CPE carriers. METHODS:We conducted a prospective case-ascertained cohort study. We identified the presence of CPE in stool samples from index subjects, household contacts and companion animals and environmental samples at regular intervals. Linked transmissions were identified by WGS. A Markov model was constructed to estimate the household transmission potential of CPE. RESULTS:Ten recently hospitalized index patients and 14 household contacts were included. There were seven households with one contact, two households with two contacts, and one household with three contacts. Index patients were colonized with blaOXA-48-like (n = 4), blaKPC-2 (n = 3), blaIMP (n = 2), and blaNDM-1 (n = 1), distributed among divergent species of Enterobacteriaceae. After a cumulative follow-up time of 9.0 years, three family members (21.4%, 3/14) acquired four different types of CPE in the community (hazard rate of 0.22/year). The probability of CPE transmission from an index patient to a household contact was 10% (95% CI 4%-26%). CONCLUSIONS:We observed limited transmission of CPE from an index patient to household contacts. Larger studies are needed to understand the factors associated with household transmission of CPE and identify preventive strategies.
    背景与目标: 目的:估算在最近住院的携带CPE携带者的家庭中产生碳青霉烯酶的肠杆菌科(CPE)的传播率。
    方法:我们进行了一项前瞻性病例确诊队列研究。我们确定了规律性时间间隔中,来自索引受试者,家庭接触者和伴侣动物的粪便样本以及环境样本中存在CPE。 WGS确定了链接的传输。建立了一个马尔可夫模型来估计CPE的家庭传播潜力。
    结果:包括十名最近住院的索引患者和14位家庭成员。有7个家庭的1个联系人,2个家庭的2个联系人和1个有3个联系人的家庭。索引患者定植于不同肠杆菌科的blaOXA-48-like(n = 4),blaKPC-2(n = I3),blaIMP(n = 2)和blaNDM-1(n = 1)。经过9.0年的累积随访时间,三名家庭成员(21.4%,3/14)在社区中获得了四种不同类型的CPE(风险率为0.22 /年)。 CPE从索引患者传播到家庭成员的可能性为10%(95%CI 4%-26%)。
    结论:我们观察到CPE从索引患者到家庭接触者的传播有限。需要更大的研究来了解与CPE家庭传播相关的因素并确定预防策略。
  • 【奇异变形杆菌中广谱β-内酰胺酶,AmpC和碳青霉烯酶生产的流行病学。】 复制标题 收藏 收藏
    DOI:10.7883/yoken.67.44 复制DOI
    作者列表:Datta P,Gupta V,Arora S,Garg S,Chander J
    BACKGROUND & AIMS: :Proteus mirabilis strains that produce extended-spectrum β-lactamase (ESBL), AmpC β-lactamase, and carbapenemase pose potential threats to patient care because most clinical diagnostic laboratories may not attempt to detect these three major groups of enzymes. Therefore, the objective of this study was to ascertain if P. mirabilis isolates collected from our heathcare facility possess various mechanisms of resistance to β-lactams (i.e., ESBL, AmpC, and carbapenemases) and to additionally arrive at conclusions regarding concurrent testing for these three mechanism of drug resistance in order to reduce cost and time in routine diagnostic testing. Between January 2011 and June 2011, 60 consecutive non-repeated strains of P. mirabilis were evaluated for production of ESBLs, AmpC β-lactamases, and carbapenemases. Of these, 36 isolates were found to be ESBL producers, and 7 (12%) were positive for production of AmpC β-lactamases and ESBLs. Therefore, 19.4% of ESBL-producing Proteus strains coproduced AmpC enzymes. The modified Hodge test confirmed carbapenemase production in only 1 isolate (1.7%), which was also ESBL- and AmpC-positive. The clinical impact of additional AmpC expression in ESBL-producing P. mirabilis results in a newly acquired resistance to β-lactamase inhibitors. In addition, to save time and costs, we recommend the use of cefepime/cefepime-clavulanate or boronic acid for the ESBL detection but in only those strains that were positive for ESBL by screening and negative by confirmatory tests.
    背景与目标: :产生超广谱β-内酰胺酶(ESBL),AmpCβ-内酰胺酶和碳青霉烯酶的奇异变形杆菌菌株对患者的护理构成潜在威胁,因为大多数临床诊断实验室可能不会尝试检测这三大类酶。因此,本研究的目的是确定从我们的医疗卫生设施中收集的奇异假单胞菌分离株是否具有多种对β-内酰胺类药物的抗药性(即ESBL,AmpC和碳青霉烯酶),并得出关于同时检测这些细菌的结论。三种耐药机制是为了减少常规诊断测试的成本和时间。在2011年1月至2011年6月之间,对60株连续的非重复性狂犬疟原虫菌株进行了ESBLs,AmpCβ-内酰胺酶和碳青霉烯酶生产的评估。在这些菌株中,发现有36株是ESBL的产生者,其中7株(占12%)的AmpCβ-内酰胺酶和ESBLs阳性。因此,产生ESBL的变形杆菌菌株中有19.4%共同产生AmpC酶。改良的Hodge测试确认只有1个分离株(1.7%)中碳青霉烯酶的产生,而ESBL和AmpC也是阳性的。在产生ESBL的奇异假单胞菌中额外的AmpC表达的临床影响导致新获得的对β-内酰胺酶抑制剂的耐药性。此外,为节省时间和成本,我们建议使用头孢吡肟/头孢吡肟-克拉维酸盐或硼酸进行ESBL检测,但仅适用于通过筛选而对ESBL呈阳性而经确认试验呈阴性的菌株。
  • 【在产生大光谱β-内酰胺酶和碳青霉烯酶的肠杆菌的粪便中检测大肠杆菌ST131克隆复合体(ST705)和肺炎克雷伯菌ST15。】 复制标题 收藏 收藏
    DOI:10.1099/jmm.0.000399 复制DOI
    作者列表:Ríos E,López MC,Rodríguez-Avial I,Culebras E,Picazo JJ
    BACKGROUND & AIMS: PURPOSE:The objective of the present study was to evaluate the prevalence of intestinal colonization with extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae (ESBL-E) and carbapenemase-producing Enterobacteriaceae (CPE) in non-selected hospitalized and non-hospitalized patients from the same geographic area of Madrid. METHODOLOGY:A total of 501 fecal samples were screened. Diluted samples in saline were cultured in MacConkey agar plates with ceftazidime, cefotaxime, imipenem and meropenem disks. Colonies growing within the inhibition zone of either disk were selected. Characterization of ESBLs and CPEs were performed by PCR and sequencing. The Wider system was used for the bacterial identification. In addition, clonal analysis was carried out for species predominant among the fecal carriage. KEY FINDINGS:Among the 501 patients enrolled, 43 (8.6 %) carried ESBL-E and 8 (1.6 %) patients exhibited CPE. The main intestinal colonizer among ESBL-E was CTX-M-producing Escherichia coli isolates in both settings (community and hospital). ST131 clonal complex was the most common among faecal ESBL-producing E. coli. All gut carriers of CPE were hospitalized patients, Klebsiella pneumoniae being the most prevalent species. Two OXA-48-producing K. pneumoniae isolates belonging to ST15 were detected. CONCLUSION:Present study reveals that faecal carriage of ESBL is common among inpatients and outpatients, whereas carbapenemase producers are only present in the hospital setting. Therefore, active surveillance will be useful for reducing transmission of antimicrobial-resistant bacteria and preventing infection.
    背景与目标: 目的:本研究的目的是评估在非选择住院和非选择医院中,产生超广谱β-内酰胺酶(ESBL)的肠杆菌科(ESBL-E)和产生碳青霉烯酶的肠杆菌(CPE)在肠道菌落中的患病率。来自马德里同一地理区域的住院患者。
    方法:总共筛选了501份粪便样品。盐水稀释后的样品在MacConkey琼脂平板中用头孢他啶,头孢噻肟,亚胺培南和美洛培南圆盘培养。选择在任一盘的抑制区内生长的菌落。通过PCR和测序对ESBL和CPE进行表征。 Wider系统用于细菌鉴定。此外,对粪便运输中的主要物种进行了克隆分析。
    主要发现:在入选的501例患者中,有43例(8.6%)携带ESBL-E,8例(1.6 %%)表现为CPE。在两种环境(社区和医院)中,ESBL-E中主要的肠道菌落是产生CTX-M的大肠杆菌分离株。 ST131克隆复合体是在粪便中产生ESBL的大肠杆菌中最常见的一种。所有的CPE肠道携带者都是住院患者,肺炎克雷伯菌是最普遍的物种。检测到两个属于ST15的产生OXA-48的肺炎克雷伯菌分离株。
    结论:目前的研究表明,ESBL的粪便运输在住院和门诊病人中很普遍,而碳青霉烯酶生产者仅在医院就诊。因此,主动监测对于减少抗微生物细菌的传播和预防感染将是有用的。
  • 【中国山东省,产生碳青霉烯酶的肺炎克雷伯菌的特征。】 复制标题 收藏 收藏
    DOI:10.3892/etm.2017.4070 复制DOI
    作者列表:Jin Y,Song X,Liu Y,Wang Y,Zhang B,Fan H,Shao C
    BACKGROUND & AIMS: :The goal of the present study was to examine the characteristics of carbapenem-resistant Klebsiella pneumoniae as a cause of neonatal infection. A total of 37 carbapenem-resistant Klebsiella pneumoniae-positive newborns hospitalized in Shandong Provincial Hospital, China between April 2011 and October 2013 were examined. Antibiotic susceptibility testing was performed using the agar dilution method and the Etest. Resistance genes were assessed by polymerase chain reaction (PCR) and sequencing. Pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) were used to determine the genotypes and homology of these isolates. Plasmids were analyzed by PFGE and conjugation experiments. The outer membrane proteins were examined by PCR and SDS-PAGE. All of the isolates were revealed to be resistant to the third and fourth generation cephalosporins and piperacillin-tazobactam. Tigecycline, colistin, levofloxacin and amikacin were successful against all of the isolates. The antibiotic resistance rates of aztreonam, gentamicin, trimethoprim-sulfamethoxazole and fosfomycin were 13.51, 48.64, 78.38 and 86.49%, respectively. Of the 37 cases, 25 isolates (67.57%) were blaNDM-1 positive, 13 isolates (35.14%) were blaIMP-4 positive and 1 isolate (2.70%) was blaIMP-8 positive. Two isolates carried both blaNDM-1 and blaIMP-4. The isolate carrying 2-4 plasmids and blaNDM-1 and blaIMP-4 was transferable between strains. SDS-PAGE data indicated that outer membrane proteins remained present. PFGE revealed 7 distinct clusters, and MLST reported the presence of ST20, ST17, ST54, ST705 and ST290 sequences, which indicated that there was clone and plasmid spread between newborns. The main resistance mechanism of carbapenem-resistant Klebsiella pneumoniae was that the isolates expressed the carbapenemase resistance of blaNDM-1 and blaIMP-4 genes. The current study indicates that early detection of these genes may be helpful in infection prevention and control.
    背景与目标: :本研究的目的是检查耐碳青霉烯类肺炎克雷伯菌的特征,以作为新生儿感染的原因。 2011年4月至2013年10月,在中国山东省立医院共住院治疗了37例对碳青霉烯耐药的肺炎克雷伯菌阳性婴儿。使用琼脂稀释法和Etest进行抗生素敏感性测试。通过聚合酶链反应(PCR)和测序评估抗性基因。脉冲场凝胶电泳(PFGE)和多位点序列分型(MLST)用于确定这些分离株的基因型和同源性。通过PFGE和缀合实验分析质粒。外膜蛋白通过PCR和SDS-PAGE检查。所有分离株均显示对第三代和第四代头孢菌素和哌拉西林-他唑巴坦有抗药性。替加环素,粘菌素,左氧氟沙星和丁胺卡那霉素对所有分离株均成功。氨曲南,庆大霉素,甲氧苄氨磺胺甲基异恶唑和磷霉素的耐药率分别为13.51%,48.64%,78.38%和86.49%。在这37例病例中,有25株(67.57%)blaNDM-1阳性,13株(35.14%)blaIMP-4阳性,1株(2.70%)blaIMP-8阳性。两种分离株均携带blaNDM-1和blaIMP-4。带有2-4个质粒以及blaNDM-1和blaIMP-4的分离株可在菌株之间转移。 SDS-PAGE数据表明外膜蛋白仍然存在。 PFGE揭示了7个不同的簇,并且MLST报告了ST20,ST17,ST54,ST705和ST290序列的存在,这表明在新生儿之间存在克隆和质粒传播。对碳青霉烯类耐药的肺炎克雷伯菌的主要耐药机制是分离株表达了blaNDM-1和blaIMP-4基因对碳青霉烯酶的耐药性。当前的研究表明,这些基因的早期检测可能有助于预防和控制感染。
  • 【2013年至2018年,通过全基因组测序追踪生产碳青霉烯酶的肺炎克雷伯菌ST512的局部和区域簇。】 复制标题 收藏 收藏
    DOI:10.2807/1560-7917.ES.2019.24.38.1800522 复制DOI
    作者列表:van Beek J,Räisänen K,Broas M,Kauranen J,Kähkölä A,Laine J,Mustonen E,Nurkkala T,Puhto T,Sinkkonen J,Torvinen S,Vornanen T,Vuento R,Jalava J,Lyytikäinen O
    BACKGROUND & AIMS: :BackgroundTwo epidemiologically-unrelated clusters of Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae were detected among several healthcare facilities (HCF) in Finland by routine surveillance using whole genome sequencing (WGS).AimThe objective was to investigate transmission chains to stop further spread of the responsible strain.MethodsIn this observational retrospective study, cases were defined as patients with K. pneumoniae KPC-3 sequence type (ST)512 strain detected in Finland from August 2013 to May 2018. Environmental specimens were obtained from surfaces, sinks and toilets in affected wards. WGS was performed on K. pneumoniae cultures using Illumina MiSeq platform and data were analysed using Ridom SeqShere software K. pneumoniae core genome multilocus sequence typing (cgMLST) scheme. Epidemiological information of the cases was provided by HCFs.ResultsWe identified 20 cases in six HCFs: cluster 1 included 18 cases in five HCFs and cluster 2 two cases in one HCF. In cluster 1, a link with a foreign country was unclear, 6/18 cases without overlapping stay had occupied the same room in one of the five HCFs within > 3 years. In cluster 2, the index case was transferred from abroad, both cases occupied the same room 8 months apart. A strain identical to that of the two cases in cgMLST was isolated from the toilet of the room, suggesting a clonal origin.ConclusionsThe clusters were mostly related to case transfer between facilities and likely involved environmental transmission. We show that CPE surveillance using WGS and collaboration between hospitals are crucial to identify clusters and trace transmission chains.
    背景与目标: 背景:通过全基因组测序(WGS)的常规监测,在芬兰的几个医疗机构(HCF)中发现了两个与流行病学无关的产肺炎克雷伯菌肺炎克雷伯菌(KPC)的肺炎克雷伯菌。方法在此观察性回顾性研究中,病例定义为2013年8月至2018年5月在芬兰检测到的肺炎克雷伯氏菌KPC-3序列型(ST)512菌株患者。受影响病房的厕所。使用Illumina MiSeq平台在肺炎克雷伯菌培养上进行WGS,并使用Ridom SeqShere软件对肺炎克雷伯菌核心基因组多基因座序列分型(cgMLST)方案进行数据分析。结果我们从6个HCF中获得了20例病例的流行病学信息。结果我们在6个HCF中确定了20例:1组中包括5个HCF中的18例,2组中1个HCF中的2例。在集群1中,与外国的联系尚不清楚,在3年内,有5/6个HCF中有6/18个没有重叠逗留的案件占据了同一房间。在第二类集群中,索引案例是从国外转移的,这两个案例相隔8个多月位于同一房间。从房间的洗手间中分离出与cgMLST的两例相同的菌株,表明是克隆起源。结论簇主要与设施之间的病例转移有关,可能涉及环境传播。我们表明,使用WGS和医院之间的协作进行的CPE监视对于识别集群和跟踪传输链至关重要。
  • 【革兰氏阴性杆菌中是否存在多种β-内酰胺酶,是否会影响抗菌药敏试验以及超广谱β-内酰胺酶和碳青霉烯酶确认方法的结果?】 复制标题 收藏 收藏
    DOI:10.1016/j.jgar.2020.08.011 复制DOI
    作者列表:Tenover FC,Dela Cruz CM,Dewell S,Le VM,Tickler IA
    BACKGROUND & AIMS: OBJECTIVES:Many multidrug-resistant Gram-negative bacilli (MDR-GNB) harbour multiple β-lactamases. The aim of this study was to assess the impact of multiple β-lactamase carriage on the accuracy of susceptibility tests and extended-spectrum β-lactamase (ESBL) and carbapenemase confirmation methods. METHODS:A total of 50 MDR-GNB, of which 29 carried multiple β-lactamases, underwent broth microdilution (BMD) and disk diffusion (DD) testing as well as confirmation tests for ESBLs and carbapenemases. Whole-genome sequencing (WGS) was used for β-lactamase gene identification. RESULTS:Categorical agreement of BMD and DD testing results ranged from 86.5 to 97.7% for 10 β-lactam agents. BMD and DD algorithms for ESBL detection were highly variable; 6 of 8 positive strains carried an ESBL plus a carbapenemase or an AmpC enzyme, which may confound antimicrobial selection. The sensitivity and specificity of the modified carbapenem inactivation method (mCIM) were both 100%, whilst mCIM and EDTA-modified carbapenem inactivation method (eCIM) when used together to differentiate serine from metallo-β-lactamase carriage were both 96%. Xpert® Carba-R results (in vitro diagnostic test) were consistent with WGS results. Predicting phenotypic carbapenem resistance from WGS data overall showed 100% specificity but only 66.7% sensitivity for Enterobacterales isolates that were non-susceptible to imipenem and meropenem. CONCLUSIONS:Multiple β-lactamases in MDR-GNB does not impact DD results, the utility of mCIM/eCIM tests, or Xpert Carba-R results. However, ESBL algorithms produced inconsistent results and predicting carbapenem resistance from WGS data was problematic in such strains.
    背景与目标: 目的:许多具有多重耐药性的革兰氏阴性杆菌(MDR-GNB)都带有多种β-内酰胺酶。这项研究的目的是评估多重β-内酰胺酶运输对药敏试验,超广谱β-内酰胺酶(ESBL)和碳青霉烯酶确认方法准确性的影响。
    方法:总共50个MDR-GNB,其中29个带有多种β-内酰胺酶,进行了肉汤微稀释(BMD)和圆盘扩散(DD)测试以及ESBL和碳青霉烯酶的确认测试。全基因组测序(WGS)用于β-内酰胺酶基因鉴定。
    结果:对于10种β-内酰胺类药物,BMD和DD检测结果的分类一致性在86.5%至97.7%之间。用于ESBL检测的BMD和DD算法变化很大。 8株阳性菌株中有6株带有ESBL加碳青霉烯酶或AmpC酶,可能会混淆抗菌药物的选择。修饰的碳青霉烯灭活方法(mCIM)的敏感性和特异性均为100%,而mCIM和EDTA修饰的碳青霉烯灭活方法(eCIM)一起用于区分丝氨酸和金属β-内酰胺酶携带,两者的敏感性和特异性均为96%。 Xpert®Carba-R结果(体外诊断测试)与WGS结果一致。从WGS数据总体预测表型碳青霉烯耐药性显示100%的特异性,但对亚胺培南和美洛培南不敏感的肠杆菌分离株的敏感性仅为66.7%。
    结论:MDR-GNB中的多个β-内酰胺酶不会影响DD结果,mCIM / eCIM测试的实用性或Xpert Carba-R结果。然而,ESBL算法产生的结果不一致,并且从WGS数据预测碳青霉烯类耐药性在此类菌株中存在问题。
  • 【碳青霉烯酶生产者在全世界肠杆菌科中的传播难以控制。】 复制标题 收藏 收藏
    DOI:10.1111/1469-0691.12719 复制DOI
    作者列表:Nordmann P,Poirel L
    BACKGROUND & AIMS: :The spread of carbapenemase producers in Enterobacteriaceae has now been identified worldwide. Three main carbapenemases have been reported; they belong to three classes of β-lactamases, which are KPC, NDM, and OXA-48. The main reservoirs of KPC are Klebsiella pneumoniae in the USA, Israel, Greece, and Italy, those of NDM are K. pneumoniae and Escherichia coli in the Indian subcontinent, and those of OXA-48 are K. pneumoniae and Escherichia coli in North Africa and Turkey. KPC producers have been mostly identified among nosocomial isolates, whereas NDM and OXA-48 producers are both nosocomial and community-acquired pathogens. Control of their spread is still possible in hospital settings, and relies on the use of rapid diagnostic techniques and the strict implemention of hygiene measures.
    背景与目标: :碳青霉烯酶生产者在肠杆菌科中的传播现已在全球范围内确定。已经报道了三种主要的碳青霉烯酶。它们属于三类β-内酰胺酶,分别是KPC,NDM和OXA-48。 KPC的主要储层是美国,以色列,希腊和意大利的肺炎克雷伯菌,NDM的储层是印度次大陆的肺炎克雷伯菌和大肠埃希菌,OXA-48的储层是北非的肺炎克雷伯菌和大肠埃希菌。和土耳其。 KPC生产者主要是在医院分离株中鉴定的,而NDM和OXA-48生产者既是医院病原体,又是社区获得性病原体。在医院中仍然可以控制它们的传播,这取决于使用快速诊断技术和严格执行卫生措施。
  • 【在意大利的一个新生儿重症监护病房,成功控制了产肺炎克雷伯菌肺炎克雷伯菌酶的克雷伯菌肺炎克雷伯菌序列类型258的定殖暴发。】 复制标题 收藏 收藏
    DOI:10.1016/j.jhin.2013.08.004 复制DOI
    作者列表:Giuffrè M,Bonura C,Geraci DM,Saporito L,Catalano R,Di Noto S,Nociforo F,Corsello G,Mammina C
    BACKGROUND & AIMS: :This article reports an outbreak of colonization by Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp) sequence type (ST) 258 in a neonatal intensive care unit (NICU) in Palermo, Italy. KPC-Kp ST258 was detected by an active surveillance culture programme. Between 18th September and 14th November 2012, KPC-Kp was isolated from 10 out of 54 neonates admitted in the outbreak period. No cases of infection were recorded. Male sex was associated with colonization, whereas administration of ampicillin- sulbactam plus gentamicin was protective. Infection control interventions interrupted the spread of KPC-Kp without the need to close the NICU to new admissions.
    背景与目标: :本文报道了意大利巴勒莫市新生儿重症监护病房(NICU)产肺炎克雷伯菌肺炎克雷伯菌酶(KPC-Kp)序列类型(ST)258的定殖事件。 KPC-Kp ST258已通过积极的监视文化计划检测到。在2012年9月18日至11月14日期间,KPC-Kp与爆发期间入院的54例新生儿中的10例分离。没有记录到感染病例。男性与定植有关,而氨苄西林舒巴坦加庆大霉素的使用具有保护性。感染控制干预措施可以中断KPC-Kp的传播,而无需关闭重症监护病房(NICU)以接受新的入院治疗。
  • 【新德里金属β-内酰胺酶-1抑制剂肽的发现和表征,该肽增强了美罗培南依赖性的产生碳青霉烯酶的肠杆菌科细菌的杀伤。】 复制标题 收藏 收藏
    DOI:10.1093/jac/dkaa242 复制DOI
    作者列表:Kazi MI,Perry BW,Card DC,Schargel RD,Ali HB,Obuekwe VC,Sapkota M,Kang KN,Pellegrino MW,Greenberg DE,Castoe TA,Boll JM
    BACKGROUND & AIMS: OBJECTIVES:Metallo-β-lactamases (MBLs) are an emerging class of antimicrobial resistance enzymes that degrade β-lactam antibiotics, including last-resort carbapenems. Infections caused by carbapenemase-producing Enterobacteriaceae (CPE) are increasingly prevalent, but treatment options are limited. While several serine-dependent β-lactamase inhibitors are formulated with commonly prescribed β-lactams, no MBL inhibitors are currently approved for combinatorial therapies. New compounds that target MBLs to restore carbapenem activity against CPE are therefore urgently needed. Herein we identified and characterized novel synthetic peptide inhibitors that bound to and inhibited NDM-1, which is an emerging β-lactam resistance mechanism in CPE. METHODS:We leveraged Surface Localized Antimicrobial displaY (SLAY) to identify and characterize peptides that inhibit NDM-1, which is a primary carbapenem resistance mechanism in CPE. Lead inhibitor sequences were chemically synthesized and MBCs and MICs were calculated in the presence/absence of carbapenems. Kinetic analysis with recombinant NDM-1 and select peptides tested direct binding and supported NDM-1 inhibitor mechanisms of action. Inhibitors were also tested for cytotoxicity. RESULTS:We identified approximately 1700 sequences that potentiated carbapenem-dependent killing against NDM-1 Escherichia coli. Several also enhanced meropenem-dependent killing of other CPE. Biochemical characterization of a subset indicated the peptides penetrated the bacterial periplasm and directly bound NDM-1 to inhibit enzymatic activity. Additionally, each demonstrated minimal haemolysis and cytotoxicity against mammalian cell lines. CONCLUSIONS:Our approach advances a molecular platform for antimicrobial discovery, which complements the growing need for alternative antimicrobials. We also discovered lead NDM-1 inhibitors, which serve as a starting point for further chemical optimization.
    背景与目标: 目的:金属-β-内酰胺酶(MBLs)是一类新兴的抗微生物耐药性酶,可降解β-内酰胺类抗生素,包括最后一种碳青霉烯。由产生碳青霉烯酶的肠杆菌科(CPE)引起的感染越来越普遍,但治疗选择有限。尽管几种丝氨酸依赖性β-内酰胺酶抑制剂与通常处方的β-内酰胺一起配制,但目前尚无MBL抑制剂被批准用于组合疗​​法。因此,迫切需要靶向MBL的新化合物,以恢复针对CPE的碳青霉烯活性。本文中,我们鉴定并表征了与NDM-1结合并抑制NDM-1的新型合成肽抑制剂,NDM-1是CPE中新兴的β-内酰胺抗性机制。
    方法:我们利用表面局部抗菌素置换(SLAY)来鉴定和表征抑制NDM-1的肽,这是CPE中主要的碳青霉烯耐药机制。化学合成先导抑制剂序列,并在碳青霉烯存在/不存在下计算MBC和MIC。用重组NDM-1和选择的肽进行的动力学分析测试了直接结合和支持的NDM-1抑制剂的作用机理。还测试了抑制剂的细胞毒性。
    结果:我们鉴定了大约1700个序列,可增强碳青霉烯类药物对NDM-1大肠杆菌的杀伤作用。一些还增强了对其他CPE的美洛培南依赖性杀伤。子集的生化特征表明,肽穿透细菌周质并直接结合NDM-1以抑制酶活性。另外,每个都表现出最小的针对哺乳动物细胞系的溶血作用和细胞毒性。
    结论:我们的方法为抗菌药物发现提供了分子平台,从而补充了对替代抗菌药物日益增长的需求。我们还发现了NDM-1铅抑制剂,可作为进一步化学优化的起点。
  • 【在瑞士伴侣动物诊所中,不良的感染预防和控制标准与产生碳青霉烯酶的肠杆菌和其他耐多药细菌的环境污染有关。】 复制标题 收藏 收藏
    DOI:10.1186/s13756-020-00742-5 复制DOI
    作者列表:Schmidt JS,Kuster SP,Nigg A,Dazio V,Brilhante M,Rohrbach H,Bernasconi OJ,Büdel T,Campos-Madueno EI,Gobeli Brawand S,Schuller S,Endimiani A,Perreten V,Willi B
    BACKGROUND & AIMS: BACKGROUND:Intensive medical care in companion animal clinics could pose a risk for the selection and dissemination of multidrug-resistant organisms (MDROs). Infection prevention and control (IPC) concepts are key measures to reduce the spread of MDROs, but data on IPC standards in companion animal clinics is sparse. The study assessed IPC standards in seven companion animal clinics and practices in Switzerland by structured IPC audits and combined results with environmental MDRO contamination and MDRO carriage of the personnel. METHODS:IPC audits were held between August 2018 and January 2019. The observations in 34 IPC areas were scored based on predefined criteria (not fulfilled/partially fulfilled/fulfilled = score 0/1/2). Environmental swabs and nasal and stool samples from veterinary personnel were tested for methicillin-resistant (MR) staphylococci and macrococci and for colistin-resistant, extended-spectrum β-lactamase- and carbapenemase-producing (CP) Enterobacterales (CPE). Species was identified by MALDI-TOF MS, antimicrobial resistance determined by microdilution and β-lactam resistance gene detection, and genetic relatedness assessed by REP-/ERIC-PCR and multilocus sequence typing. RESULTS:Of a maximum total IPC score of 68, the institutions reached a median (range) score of 33 (19-55). MDROs were detected in median (range) 8.2% (0-33.3%) of the sampling sites. Clinics with low IPC standards showed extensive environmental contamination, i.e. of intensive care units, consultation rooms and utensils. CPE were detected in two clinics; one of them showed extensive contamination with CP Klebsiella pneumoniae (ST11, blaOXA-48) and MR Staphylococcus pseudintermedius (ST551, mecA). Despite low IPC scores, environmental contamination with MDROs was low in primary opinion practices. Three employees were colonized with Escherichia coli ST131 (blaCTX-M-15, blaCTX-M-27, blaCTX-M-14). Two employees carried CP E. coli closely related to environmental (ST410, blaOXA-181) and patient-derived isolates (ST167, blaNDM-5). MR Staphylococcus aureus (ST225, mecA) and MR S. pseudintermedius (ST551, mecA) of the same sequence types and with similar resistance profiles were found in employees and the environment in two clinics. CONCLUSIONS:The study indicates that IPC standards in companion animal clinics are variable and that insufficient IPC standards could contribute to the evolution of MDROs which can be transferred between the environment and working personnel. The implementation of IPC concepts in companion animal clinics should urgently be promoted.
    背景与目标: 背景:在伴侣动物诊所进行的深入医疗可能会带来选择和传播耐多药生物(MDRO)的风险。感染预防和控制(IPC)概念是减少MDRO传播的关键措施,但伴侣动物诊所中有关IPC标准的数据很少。该研究通过对IPC进行结构化审核,评估了瑞士7家伴侣动物诊所和诊所的IPC标准,并将结果与​​环境MDRO污染和人员MDRO运送相结合。
    方法:IPC审核于2018年8月至2019年1月进行。在34个IPC区域中的观察结果是根据预定义的标准进行评分的(未实现/部分实现/完成=得分0/1/2)。对来自兽医人员的环境拭子以及鼻和粪便样本进行了耐甲氧西林(MR)葡萄球菌和大球菌检测,以及大肠菌素抗性,广谱β-内酰胺酶和碳青霉烯酶生产(CP)肠杆菌(CPE)测试。通过MALDI-TOF MS鉴定物种,通过微稀释和β-内酰胺抗性基因检测确定抗药性,并通过REP- / ERIC-PCR和多基因座序列分型评估遗传相关性。
    结果:在最高IPC总分中,这些机构的平均分(范围)为33(19-55),最高得分为68。在采样点的中位数(范围)8.2%(0-33.3%)中检测到MDRO。 IPC标准较低的诊所显示出广泛的环境污染,即重症监护室,诊疗室和用具。在两家诊所中检测到了CPE;其中之一显示广泛感染了肺炎克雷伯氏菌(ST11,blaOXA-48)和MR假单胞菌葡萄球菌(ST551,mecA)。尽管IPC得分较低,但在主要舆论实践中,MDRO对环境的污染仍然较低。三名员工被大肠杆菌ST131(blaCTX-M-15,blaCTX-M-27,blaCTX-M-14)定殖。两名员工携带与环境(ST410,blaOXA-181)和患者分离株(ST167,blaNDM-5)密切相关的CP大肠杆菌。在两家诊所的员工和环境中发现了具有相同序列类型和相似耐药性的金黄色葡萄球菌(ST225,mecA)和假单胞菌(pseudintermedius)(ST551,mecA)。
    结论:该研究表明,伴侣动物诊所的IPC标准是可变的,IPC标准不足可能会导致MDRO的进化,MDRO可以在环境和工作人员之间转移。迫切需要在伴侣动物诊所中实施IPC概念。
  • 【一步突变后,可以表达脆弱拟杆菌(Bacteroides fragilis)菌株中的沉默碳青霉烯酶基因。】 复制标题 收藏 收藏
    DOI:10.1016/0378-1097(92)90557-5 复制DOI
    作者列表:Podglajen I,Breuil J,Bordon F,Gutmann L,Collatz E
    BACKGROUND & AIMS: :High-level carbapenem-resistant (CpmR) mutants, with MICs for imipenem and carbapenem of greater than 128 micrograms/ml, were selected in vitro from four carbapenem-susceptible (CpmS) clinical isolates of Bacteroides fragilis. The CpmS strains produced very low levels of beta-lactamase activity, which was increased approx. 50- to 100-fold in the CpmR mutants. Isoelectric focussing and enzyme kinetic analysis (Km and Vrel) of the 'carbapenemases' from the CpmR mutants and similarly resistant clinical isolates suggested a close relatedness of the enzymes. A probe covering most of the cfiA gene encoding such an enzyme (Thompson, J.S. and Malamy, M.H. (1990) J. Bacteriol. 172, 2584-2593) hybridized with DNA from the CpmR mutants, their CpmS parental strains as well as clinical CpmR isolates, but not from randomly chosen carbapenem-susceptible strains. The possibility is considered that mutations leading to expression of the silent carbapenemase gene, and thereby to clinically relevant carbapenem resistance, may also occur in the clinical setting.
    背景与目标: :从四个脆弱类拟杆菌细菌临床分离株中筛选出高抗碳青霉烯(CpmR)突变体,亚胺培南和碳青霉烯的MIC均大于128微克/毫升。 CpmS菌株产生非常低水平的β-内酰胺酶活性,其活性大约增加。 CpmR突变体的50到100倍。等电点聚焦和酶动力学分析(Km和Vrel)来自CpmR突变体和具有类似抗药性的临床分离株的“卡宾碳烯”,表明这些酶具有密切的相关性。一种探针,覆盖了大多数编码这种酶的cfiA基因(Thompson,JS和Malamy,MH(1990)J. Bacteriol。172,2584-2593),与来自CpmR突变体,其CpmS亲本菌株以及临床CpmR的DNA杂交分离株,但不是随机选择的碳青霉烯敏感株。据认为,在临床环境中也可能发生导致沉默碳青霉烯酶基因表达并由此引起临床相关的碳青霉烯耐药性的突变。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录