Molecular epidemiology and antibiotic resistance of Enterobacter spp. from three distinct populations in Grampian,UK

The distribution of Enterobacter spp. within the population of Aberdeen Royal Infirmary was compared with the outpatient population with regard to molecular epidemiology and antibiotic resistance. Enterobacter spp. from 60 patients and one environmental site were characterised as ITU, non ITU and outpatients’ isolates. Thirty-five percent were blood culture isolates. Cefotaxime resistant strains in the hospital were frequent. Cefotaxime (64%) sensitive isolates were inducible for hyperproduction of Bush group 1 β-lactamase. Isolates were further investigated by PFGE. Isolates (27%) were clonally related and typed in four clusters. Consecutive isolates were studied in selected patients showing minor genomic changes. One environmental isolate from a deep sink at ITU was related to a patient's isolate.     

ESBLs在大肠埃希菌、肺炎克雷伯菌和阴沟肠杆菌中的检出率及耐药情况比较

目的检测我国大肠埃希菌、肺炎克雷伯菌和阴沟肠杆菌中超广谱β-内酰胺酶(ESBLs)产生及耐药情况。方法对2000-2001年中国细菌耐药监测研究所收集的来自9座城市13家医院的大肠埃希菌、肺炎克雷伯菌和阴沟肠杆菌采用平皿二倍稀释法测定抗菌药物对各种致病菌的MIC值，计算MIC50与MIC90，并按NCCLS2002规定的临界浓度，求出各类细菌对所测定的各种抗菌药物的耐药率(R％)。以纸片扩散法确证试验检测产ESBLs大肠埃希菌和肺炎克雷伯菌，以三维试验检测产ESBLs和AmpC酶的阴沟肠杆菌。结果在总共341株大肠埃希菌和212株肺炎克雷伯菌中共检测到产ESBLs菌100株，检出率18．1％(100／553)。其中产ESBLs大肠埃希菌63株，检出率18．5％(63／341)；产ESBLs肺炎克雷伯菌37株，检出率17．5％(37／212)。产ESBLs菌株对β-内酰胺类抗生素的耐药率明显高于非ESBLs菌株。酶抑制剂联合制剂头孢哌酮／舒巴坦、第四代头孢菌素头孢吡肟和碳青霉烯类对产ESBLs菌株有较好作用。81株阴沟肠杆菌中，28株产ESBLs，检出率34．6％；31株产AmpC酶，检出率38．3％；14株同时产生此二类酶，检出率17．3％。在对头孢曲松中介的14株阴沟肠杆菌中，AmpC酶检出率为42．9％(6／14)，而ESBLs的检出率高达92．9％(13／14)，是AmpC酶检出率的两倍多。但在对头孢曲松耐药的27株阴沟肠杆菌中．情况刚好相反，AmpC酶的检出率为88．9％(24／27)，是ESBLs检出率(40．7％，11／27)的两倍多。头孢噻肟中介和耐药株中两酶的检出情况与头孢曲松相似。头孢他啶只有1株中介株，耐药株中AmpC酶检出率(78．4％，29／37)约是ESBLs检出率(56．8%，21／37)的1．4倍。若将敏感和中介株合并计算可见，头孢他啶敏感和中介株中两酶的检出率明显低于头孢曲松和头孢噻肟。结论①细菌耐药研究显示ESBLs在大肠埃希菌和肺炎克雷伯菌中的检出率为18．1％；②ESBLs在我国阴沟肠杆菌中有很高的检出率；③在阴沟肠杆菌中，对头孢曲松和头孢噻肟中介的菌株，以产ESBLs为主，而耐药菌株以产AmpC酶为主。     

某院2015-2019年肺炎克雷伯菌的耐药性及耐药基因分析

摘要：目的 分析某院临床分离的肺炎克雷伯菌(Klebsiella pneumoniae,KP)耐药情况及耐药基因,指导临床规范使用抗菌药物。方法 收集该院2015-2019年临床分离的2416株肺炎克雷伯菌,使用VITEK-2 Compact系统对临床分离株进行细菌鉴定,药敏试验采用MIC法和K-B纸片扩散法,采用WHONET 5.6软件对菌株的标本来源、科室分布、检出率及耐药率进行统计,采用SPSS 26.0软件对5年期间菌株的检出率、耐药率进行比较及趋势分析,选取2019年内科重症监护病房(Intensive care unit,ICU)的19株耐碳青霉烯肺炎克雷伯菌(carbapenem-resistant Klebsiella pneumoniae,CR-KP),通过二代测序平台对其进行全基因组测序(whole genome sequencing, WGS),运用丹麦技术大学(DTU)基因组流行病学中心(CGE)(https://cge.cbs.dtu.dk/services/ResFinder/)的ResFinder 4.0工具进行耐药基因筛查,运用MORPHEUS(https://software.broadinstitute.org/morpheus/)在线制作耐药基因热图。结果 2015-2019年临床标本共分离出2416株KP,主要来自痰液、尿液,分别占51.7%(1249/2416)、11.3%(273/2416),科室主要分布于内科ICU、外科ICU,分别占23.2%(561/2416)、19.1%(461/2416)。每年KP的分离率呈上升趋势(χ2趋势=18.190,P＜0.001),其对常用抗菌药物的耐药率呈逐年升高趋势,除对替加环素的耐药率无法统计外,对其他各类抗菌药物的耐药率差异均有统计学意义(P＜0.001),对亚胺培南、美罗培南耐药率分别从2015年的2.9%、3.0%上升至2019年的16.0%、13.7%。5年间共检出354株CR-KP,主要来自痰液、尿液,分别占43.8%(155/354)、10.7%(38/354),分布较高的科室为外科ICU、内科ICU,分别占14.4%(51/354)、10.2%(36/354),每年的检出率呈上升趋势(χ2趋势=46.176,P＜0.001),其对各类抗菌药物的耐药率呈逐年升高趋势,除对庆大霉素的耐药率差异无统计学意义(P=0.105)、对替加环素的耐药率差异无法统计外,对其他各类抗菌药物的耐药率差异均有统计学意义(P＜0.05)。采用WGS技术对19株CR-KP进行分析,共筛查出15种耐药基因,主要包括β-内酰胺酶耐药基因(blaKPC-2)、喹诺酮类耐药基因(qnrS1)、磷霉素耐药基因(fosA)、四环素耐药基因(tetA)、氯霉素耐药基因(catA2)以及氨基糖苷类耐药基因(aadA2b、rmtB)等。结论 该院KP、CR-KP的耐药情况日趋严重,CR-KP同时携带多种耐药基因,耐药表型多样化。运用WGS结合生物信息学分析技术研究细菌耐药机制,有助于耐药菌防控措施的精准实施,未来将成为耐药菌研究的主流技术之一。     

Prevalence and mechanisms of fosfomycin resistance among KPC-producing Klebsiella pneumoniae clinical isolates in China

The threat of antibiotic resistance has increased dramatically in recent years. Fosfomycin, an old antibiotic agent, has been re-introduced to fight infections caused by Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-KP). However, the trend of fosfomycin resistance among KPC-KP strains is increasing. In this study, 80 KPC-KP clinical isolates were collected from three teaching hospitals during 2014–2017 in China and were subjected to whole-genome sequencing (WGS). The fosfomycin resistance phenotype and resistance mechanisms were investigated by antimicrobial susceptibility testing and carbon source growth test, respectively. Among all KPC-KP strains, 80.0% (64/80) were resistant to fosfomycin and 36.3% (29/80) were positive for the mobile fosfomycin resistance gene fosA3. Among the 63 strains that were unable to grow in M9 basic medium with glycerol-3-phosphate (G3P) as the sole carbon source (mediated by mutation of the target gene glpT), there was no significant difference regarding the MIC distribution of fosfomycin between fosA3-positive and fosA3-negative strains (P = 0.577). Among the 50 strains that were negative for fosA3 but positive for fosA, the fosfomycin MICs of strains unable to grow in M9 basic medium with G3P as the sole carbon source were significantly higher (P < 0.001) than in strains that were able to grow in M9 basic medium with G3P as the sole carbon source. Our findings indicate that fosfomycin resistance among KPC-KP in China is an emerging problem and the two major mechanisms of resistance identified were plasmid-mediated fosfomycin resistance gene fosA3 and mutation of the target gene glpT.     

Trends in penicillin and macrolide resistance among pneumococci in the UK and the Republic of Ireland in relation to antibiotic sales to pharmacies and dispensing doctors

It is widely believed that reducing antimicrobial usage should reduce resistance, although observational evidence is mixed. Pneumococci make ideal subjects to test this belief as they are widely surveyed and lack an animal reservoir. Accordingly, susceptibility data for pneumococci in the UK and Ireland were retrieved from the Health Protection Agency's LabBase/CoSurv system and from the European Antimicrobial Resistance Surveillance System (EARSS) and British Society for Antimicrobial Chemotherapy (BSAC) databases. The BSAC surveillance examines respiratory pneumococci; the other systems focus upon invasive organisms only, with the LabBase/CoSurv system being the most comprehensive, capturing data on most bacteraemias in England and Wales. National pharmacy sales data were obtained from the IMS Health MIDAS database and were modelled to the resistance data by logistic and linear regression analysis. All systems except for the BSAC respiratory surveillance data indicated that penicillin resistance has fallen significantly since 1999 in the UK, whereas macrolide resistance has been essentially stable, or has risen slightly. The data for Ireland were based on smaller sample sizes but suggested a fall in penicillin non-susceptibility from 1999 to 2004, with conflicting evidence for macrolide resistance. The recent decreasing trend in penicillin resistance is in contrast to a rising trend in England and Wales until (at least) 1997 and strongly rising macrolide resistance from 1989 to 1993. UK pharmacy sales of macrolides and oral beta-lactams fell by ca. 30% in the late 1990s following increased concern about resistance, before stabilising or rising weakly; sales in Ireland were stable or rose slightly in the study period. We conclude that falling penicillin resistance in pneumococci followed reduced sales of oral beta-lactams to pharmacies in the UK, but a similar fall in macrolide sales was not associated with any fall in resistance. Stabilisation or decline in penicillin resistance has occurred in Ireland despite stable or increasing oral beta-lactam sales.     

产AmpC酶阴沟肠杆菌耐药的基础与临床

目的 对四川大学华西医院阴沟肠杆菌产AmpC酶菌株的检出率、耐药性及ampC结构基因序列进行分析．探讨阴沟肠杆菌产AmpC酶菌株的耐药性及临床特点。方法 采用琼脂稀释法对临床标本中分离的阴沟肠杆菌进行产AmpC酶株的筛选，用酶粗提物头孢西丁三维试验结合PCR法检测AmpC酶．并测定产AmpC酶菌株对9种抗菌药物的MIC值。对3株高度耐药阴沟肠杆菌产AmpC酶的结构基因和1株敏感菌进行PCR扩增并对产物序列进行分析，测序的菌株与E。cloacae p99进行核苷酸序列比较和推导的氨基酸序列比较。结果 阴沟肠杆菌产AmpC酶株的检出率为24．6％。产AmpC酶菌株多呈多重耐药，产AmpC酶耐药菌对9种抗菌药物的耐药率由高至低为头孢西丁、头孢噻肟、阿米卡星、氨曲南、头孢他啶、头孢哌酮／舒巴坦、环丙沙星、头孢吡肟、亚胺培南。阴沟肠杆菌耐药株ampC结构基因的核苷酸序列与E.cloacae p99的同源性为99％．推导的氨基酸序列仅Ala-58→Pro发生点突变。结论 四川大学华西医院阴沟肠杆菌产AmpC酶细菌检出率较高。产AmpC酶细菌多呈多重耐药，亚胺培南是治疗产AmpC酶细菌感染的较可靠的药物。阴沟肠杆菌产AmpC酶是其对β-内酰胺类抗生素耐药的原因之一，其ampC结构基因突变可能与其耐药性有关。     

2012-2017年某院耐碳青霉烯肺炎克雷伯菌变迁及耐药性

目的 分析医院耐碳青霉烯肺炎克雷伯菌(CRKP)的流行趋势、分布特点及耐药性,为CRKP的防治提供临床依据。方法 调查某院2012-2017年住院患者抗菌药物使用情况及CRKP分离率和耐药数据,采用χ2检验、Spearman相关性检验等进行分析。结果 6年共分离肺炎克雷伯菌1911株,其中280株为CRKP。CRKP检出率由2012年的0.4%上升至2017年的29.5%;重症监护病房(ICU)CRKP的分离率明显高于普通病房(P<0.05);CRKP检出与碳青霉烯类、第三代头孢菌素和青霉素酶抑制剂复方制剂的使用强度呈明显的正相关(P<0.05)。CRKP株对大多数抗菌药物的耐药率超过90%。结论 该院CRKP分离率较高,与入住ICU及广谱β-内酰胺类、碳青霉烯类的用量有关,呈现多重耐药性。应加强抗菌药物管理,强化消毒、隔离等医院感染控制措施,以减少耐药株的播散和流行。     

Ionized magnesium and calcium concentration and their ratio in equine plasma samples as determined by a regulatory laboratory compared to a clinical reference laboratory

Magnesium sulfate (MgSO₄) was administered to calm competition horses. We evaluated the impact of regulatory requirements for the handling of blood samples on plasma ionized magnesium (iMg), ionized calcium (iCa), the iMg to iCa ratio, and pH. We hypothesized that iCa, iMg. and iMg/iCa would be similar among storage and collection methods. Four blood samples were collected from each of 50 horses on the same day: Group 1 – collection in a heparinized syringe and processed within hours in a clinical laboratory; Group 2 – collection into a plasma separator tube (PST) centrifuged just prior to analysis, and plasma processed as in (1); Group 3 – collection into a PST, refrigerated, shipped via overnight carrier to the United States Equestrian Federation (USEF) Equine Drug Testing and Research laboratory, centrifuged just prior to analysis, and plasma processed; and Group 4 – as in Group 3, but stored frozen at ?80°C for 90 days, thawed, and plasma processed as in Group 3. Results for iMg/iCa are unit‐less, adjusted iMg for potential influence of plasma protein and iCa, and highly correlated with iMg pH (r = ?.933; P < 0.01). Samples processed immediately in a clinical reference laboratory had the greatest iMg/iCa. Both iMg/iCa and pH predictably decreased after freezing (P < 0.001). These data suggest that the iMg/iCa mirrors alterations in iMg regardless of storage and collection methods. This understanding can facilitate the development of a regulatory threshold for the control of the nefarious use of magnesium sulfate in competing horses, and an understanding of potential changes to iMg/iCa with storage of B samples.     

一株特殊耐药表型肺炎克雷伯菌的耐药机制研究

目的 研究对氨基糖苷类抗生素产生特殊耐药现象（双抑菌圈）的肺炎克雷伯菌的耐药表型和耐药机制.方法 用K-B法、E-test法、三维试验等方法对其耐药表型进行研究.采用聚合酶链反应（PCR）技术对7种氨基糖苷类钝化酶基因、2种核糖体甲基化基因和Ⅰ类整合子进行检测,并对PCR产物测序.结果 细菌的这种特殊耐药表型是稳定的;PCR结果表明：这株菌含有Aac（3）-Ⅱ钝化酶基因、armA核糖体甲基化耐药基因和1000bp左右的Ⅰ类整合子.结论 这株菌对氨基糖苷类抗生素的耐药是多种耐药机制相互作用的结果.但是这尚不能满意地解释这种特殊的耐药现象,其机理有待进一步研究.     

2016—2018年成都某院耐碳青霉烯肺炎克雷伯菌耐药变迁#br# 及耐药机制分析

目的 分析2016—2018年四川省中医医院临床分离的耐碳青霉烯肺炎克雷伯菌(carbapenem resistant Klebsiella pneumoniae, CRKP)的耐药性变迁及耐药机制。方法 收集本院临床分离的CRKP菌株,PCR扩增碳青霉烯酶基因A类(blaKPC、blaGES、blaSME、blaIMI和blaNMC),B类(blaNDM、blaVIM、blaIMP、blaSPM、blaGIM、blaSIM)和D类(blaOXA)。结果 近3年分离的CRKP对临床常用抗生素呈高水平耐药。经PCR扩增及测序确认,74株CRKP中,82.43%携带blaKPC-2型,10.81%携带blaNDM-1型,5.41%携带blaKPC-19型。结论 3年间本院分离的CRKP对临床常用抗生素呈高度耐药,菌株产blaKPC-2和blaNDM-1是本院CRKP最主要的耐药机制。     

20株阴沟肠杆菌耐药性及耐复方磺胺甲噁唑相关基因研究

目的 探讨临床分离的阴沟肠杆菌耐药性和耐复方磺胺甲噁唑（SMZ／TMP）相关基因存在状况。方法 采用ATB药敏试验板微量肉汤法测定临床分离的20株阴沟肠杆菌对20种抗菌药物的敏感性，采用PCR检测耐复方磺胺甲略唑相关基因sull、dfrAl和dfrA17。结果 20株菌对亚胺培南和美罗培南均敏感，对其他抗菌药物的不敏感率在25．0％～100％之间。sull、dfrA1和dfrA17基因阳性率为85．0％（17／20）、5．0％（1／21）、60．0％（12／20）。结论 阴沟肠杆菌具明显的多重耐药特征。耐复方磺胺甲口恶唑相关基因携带率很高。     

20株阴沟肠杆菌耐药性及耐复方磺胺甲(口恶)唑相关基因研究

目的 探讨临床分离的阴沟肠杆菌耐药性和耐复方磺胺甲(口恶)唑(SMZ/TMP)相关基因存在状况.方法 采用ATB药敏试验板微量肉汤法测定临床分离的20株阴沟肠杆菌对20种抗菌药物的敏感性,采用PCR检测耐复方磺胺甲(口恶)唑相关基因sull、dfrA1和dfrA17.结果 20株菌对亚胺培南和美罗培南均敏感,对其他抗菌药物的不敏感率在25.0%～100%之间.sulⅠ、dfrA1和dfrA17基因阳性率为85.0%(17/20)、5.0%(1/21)、60.0%(12/20).结论 阴沟肠杆菌具明显的多重耐药特征.耐复方磺胺甲(口恶)唑相关基因携带率很高.     

Multidrug resistance in Klebsiella pneumoniae MGH78578 and cloning of genes responsible for the resistance

Klebsiella pneumoniae MGH78578, a clinical isolate, showed high level of resistance to many antimicrobial agents. We cloned genes responsible for drug resistance from chromosomal DNA of K. pneumoniae MGH78578 by shotgun method using Escherichia coli KAM32, a drug hypersensitive strain, as host. We obtained 43 hybrid plasmids that made host cells resistant to several antimicrobial agents. We classified them into 17 groups based on growth properties in the presence of each one of 9 antimicrobial agents and on restriction patterns of each hybrid plasmid. Analysis of the cloned genes must be very useful for investigation of major parts of multidrug resistance systems including multidrug efflux pumps in K. pneumoniae MGH78578 in which genome sequence is available.     

Differences in the changes in resistance patterns to third- and fourth-generation cephalosporins and piperacillin/tazobactam among Klebsiella pneumoniae and Escherichia coli clinical isolates following a restriction policy in a Greek tertiary care hospital

The aim of the present study was to investigate whether replacement of broad-spectrum cephalosporins (CEPs) by piperacillin/tazobactam (TZP) as first-line empirical therapy may have an effect on beta-lactam resistance among Klebsiella pneumoniae and Escherichia coli in a tertiary care hospital. Data regarding CEP and TZP consumption and resistance were collected on a bimonthly basis during an open-label 2-year (1 year observational and 1 year interventional) study. Consumption of ceftazidime was reduced by 64.5%. In contrast, consumption of the other third-generation CEPs (cefotaxime and ceftriaxone) remained almost stable, whereas an increase in consumption of TZP by 2.8-fold was observed. A significant decrease in resistance to third-generation cephalosporins among K. pneumoniae isolates was observed, and the incidence of extended-spectrum beta-lactamase-producing isolates was notably reduced. These findings were less evident among E. coli isolates. Despite the significant increase in TZP consumption, the respective resistance rates of both bacterial species examined have remained almost unchanged.     

Adverse influence of diazepam upon resistance to Klebsiella pneumoniae infection in mice

Male and female mice, IOPS OF1 strain, received an i.p. injection of diazepam 1,2,4 or 8 mg/kg daily for 3 days prior to i.p. challenge with Klebsiella pneumoniae. Diazepam pretreatment increased mortality due to Klebsiella pneumoniae indicating that diazepam alters natural resistance to infection. The mechanism has not been elucidated but would appear to involve T cells and/or macrophages.     

一种新的数学模型在肺炎克雷伯菌氨基糖甙类耐药指数拟合与推测中的应用

目的 构建派生于灰色模型与神经网络模型的灰色神经网络模型,探讨其在肺炎克雷伯菌氨基糖甙类耐药指数拟合及推测的应用.方法 收集中国期刊全文数据库(CNKI)及国内相关数据库文献报道的1995-2009年期间肺炎克雷伯菌氨基糖甙类药物的耐药性数据,分别应用灰色模型GM(1,1)、BP神经网络模型进行拟合推测,最后构建派生于这两种模型的GBP神经网络模型.以x2拟合优度检验及平均绝对误差(MAE)、误差标准差(RSE)、平均绝对百分误差(MAPE)衡量拟合及推测结果的合理性及准确性.结果 1995-2009年期间肺炎克雷伯菌氨基糖甙类药物的耐药指数经三种模型拟合,显示拟合优度检验结果均为x2＜x2 0.995,P＞0.995,且对比2007-2009年推测值各精度衡量标准MAE、SDE、MAPE值以GBP模型最小,提示其推测效果最佳.结论 灰色神经网络模型能以较高精度(MAPE＜5％)拟合细菌耐药性发展趋势,提高了拟合与推测结果的稳定性及可靠性,有利于为抗菌药物的选择应用及细菌耐药性控制提供参考依据.     

Cardiovascular adaptations in rats submitted to a resistance-training model

1. The present study sought to evaluate cardiovascular adaptations, such as blood pressure (BP), heart rate (HR) and cardiac hypertrophy, to resistance training (RT) in a rat model. 2. The training protocol consisted of four sets of 10-12 repetitions of the squat exercise performed at 65-75% of one repetition maximum (1RM) over 4 weeks. Animals were randomly divided into three groups: control (n = 8, CO), electrically stimulated (n = 8, ES) and trained (n = 8, TR; also electrically stimulated). Blood pressure and HR were measured by a direct method in conscious rats after the training period. 3. All groups began with similar 1RM and 1RM/bodyweight (BW) ratio, however, at the end of the protocol only the TR group was different from the beginning (56% and 50%, respectively; both P < 0.01). The CO and ES groups had similar values for cardiac chambers weight/BW ratio, HR and diastolic, systolic and mean BP. Left ventricular hypertrophy (LVH) determined by the left ventricle (LV) weight/BW ratio was increased in the TR group (12%) when compared to CO (P < 0.01) or ES groups (P < 0.01). No changes were found in the weights of the atrium or right ventricle. Diastolic (14%) and mean BP (13%) were lower in the TR group (P < 0.05), whereas systolic BP and HR remained unchanged. 4. Collectively these results demonstrate that the rat RT model used is associated with significant development of cardiac hypertrophy and lowering of resting BP. These cardiovascular adaptations seem to a result of the training exercise and not influenced by stress since circulating catecholamine levels and adrenal gland weights remained unchanged in all groups.