404株大肠埃希菌耐药性变迁分析

目的:监测我院3a间分离的大肠埃希菌的耐药情况,了解其耐药性的发展规律,以指导临床用药。方法:用VITEK-2全自动微生物鉴定药敏仪对我院2004年至2006年临床分离的404株大肠埃希菌进行监测分析。结果:大肠埃希菌产超广谱β-内酰胺酶(ESBLs)株检出率维持在很高的水平(49%～53%)。3a间分离的大肠埃希菌对广谱青霉素、第一、二代头孢菌素、复方新诺明及氟喹诺酮类的耐药率一直很高;对氨曲南、氨苄西林、三种加酶抑制剂复合青霉素和头孢噻肟耐药率逐年上升较快(P<0.05);对碳青酶烯类仍呈高度敏感。结论:大肠埃希菌对绝大部分抗生素的耐药率均逐年增加,积极加强耐药监测,合理、规范选用抗生素,才能控制耐药菌株的出现和传播。     

In vitro activity of fosfomycin against ciprofloxacin-resistant or extended-spectrum beta-lactamase-producing Escherichia coli isolated from urine and blood

In this study, we evaluated the in vitro activity of fosfomycin and 7 other comparator agents against 307 Escherichia coli isolates including ciprofloxacin-resistant or extended-spectrum beta-lactamase (ESBL)-producing isolates. Bacterial isolates were collected from urine and blood from patients at a Korean tertiary-care hospital. Among 307 E. coli isolates, 30.3% were resistant to ciprofloxacin (MIC(90), >32 mg/L) and 7.8% produced ESBLs. The highest resistance rate was observed in ampicillin (69.7%), followed by trimethoprim-sulfamethoxazole (43.0%), and then amoxicillin-clavulanate (32.2%). All isolates were susceptible to imipenem (MIC(90), 0.125 mg/L). All but 1 isolate was susceptible to fosfomycin (MIC(90), 16 mg/L), regardless of the collected sources, ciprofloxacin resistance, and ESBL production. The data showed excellent activity of fosfomycin against E. coli isolates including fluoroquinolone-resistant strains. The clinical usefulness of fosfomycin, as a 1st-line therapy for urinary tract infection, should be evaluated further, especially in regions where ciprofloxacin resistance rates are high.     

Current options for the treatment of infections due to extended-spectrum beta-lactamase-producing Enterobacteriaceae in different groups of patients

BackgroundExtended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E) are a frequent cause of invasive infections worldwide. Carbapenems are nowadays the most used drugs to treat these infections. However, due to the increasing rates of resistance to these antimicrobials, carbapenem-sparing alternatives are being investigated.Objectives and sourcesThe aim of this narrative literature review is to summarize the published information on the currently available antibiotics for the treatment of ESBL-E infections, providing specific information on three subgroups of patients: Group 1, patients with severe infections or infections from high-risk sources or in severely immunocompromised patients; Group 2, patients with non-severe infections from intermediate-risk source; and Group 3, patients with non-severe urinary tract infection.Content and implicationsFor patients in Group 1, the current data would support the use of carbapenems. For milder infections, however, particularly urinary tract infections, other non-carbapenem antibiotics can be considered in selected cases, including beta-lactam/beta-lactam inhibitor combinations, cephamycins, temocillin and aminoglycosides. While specific studies should be performed in these situations, individualized decisions may be taken in order to avoid overuse of carbapenems.     

Cefepime versus carbapenems for the treatment of urinary tract infections caused by extended-spectrum β-lactamase-producing enterobacteriaceae

The aim of this study was to evaluate the effectiveness of cefepime compared with carbapenems for the management of urinary tract infections (UTIs) caused by extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae. This was a single-centre, retrospective study among patients with a documented ESBL-producing Enterobacteriaceae UTI between 1 July 2014 and 31 January 2017. Adult patients who received either cefepime or a carbapenem for symptomatic UTI were included in the analysis. The primary endpoint was clinical failure, defined by persistence of initial UTI symptoms that required escalation of therapy. Secondary endpoints included microbiological failure and relapse within 30 days. Of a total of 106 patients included in the study, 17 received cefepime and 89 received a carbapenem. None of the patients in either group experienced clinical or microbiological failure. Relapse occurred in six patients in the carbapenem group and none in the cefepime group. In conclusion, cefepime was comparable with carbapenems in the treatment of UTIs caused by ESBL-producing Enterobacteriaceae. Its use as a carbapenem-sparing agent for this indication should be further explored.     

Travel and acquisition of multidrug-resistant Enterobacteriaceae

Bacterial resistance to antibiotics is considered a major threat to health. Enterobacteriaceae have increasingly become resistant to antibiotics through the acquisition and dissemination of extended-spectrum beta-lactamases (ESBL) that confer resistance to most beta-lactams. While ESBL-producing Enterobacteriaceae were formerly restricted to hospitals, they have now spread to community settings, especially in developing countries. The tremendous expansion of international travels contributed to the importation of multidrug-resistant Enterobacteriaceae (MRE) to low prevalence countries. Several studies reported that 21 to 51% of healthy travelers acquire a MRE when travelling abroad, depending on the visited region (Asia, and especially South Asia being associated with the highest risk – up to 85%). Traveling to Africa or the Middle East is associated with lower but still disturbing rates (13–44%). In addition, the occurrence of digestive disorders and/or diarrhea and antibiotic intake increase the risk of MRE acquisition by 2–3 folds. After traveling though, the length of MRE carriage seems to be short (< 1 month) and the risk of transmission within the household appears to be low. Nonetheless and beyond the intestinal carriage of MRE, traveling to endemic areas has also been pointed as a risk factor for infections involving MRE, mainly urinary tract infections.     

头孢美唑和头孢西丁对产与非产超广谱β内酰胺酶菌株体外抗菌活性比较

目的测定头孢美唑和头孢西丁对产ESBLs菌株的体外抗菌活性，并与非产ESBLs菌株的体外抗菌活性相比较。方法收集2004年112月华西医院各临床科室分离出的大肠埃希菌和肺炎克雷伯菌520株，采用Kirby-Bauer琼脂扩散法进行体外药敏试验并用表型确证试验检测ESBLs。结果筛选出产ESBLs菌226株，产酶菌检出率为43．5％，其中323株大肠埃希菌的ESBLs检出率为45．8％，197株肺炎克雷伯菌的ESBLs检出率为39．6％。头孢美唑对我院产ESBLs菌株体外抗菌活性优于头孢西丁。结论头霉素类抗生素可作为治疗产ESBLs菌株引起的感染的可选药物，但仍应参考药敏试验结果。我院分离的产ESBLs大肠埃希菌和肺炎克雷伯菌对头孢美唑的敏感性略优于头孢西丁。     

Characterization of carbapenemases,extended spectrum β-lactamases and molecular epidemiology of carbapenem-non-susceptible Enterobacter cloacae in a Chinese hospital in Chongqing

Carbapenem-resistant Enterobacteriaceae, including strains from multiple species harboring metallo-β-lactamases (IMP, NDM or VIM) and non-metallo (KPC) carbapenemases, as well as those combining an extended-spectrum β-lactamase (ESBL) enzyme with porin loss, present an increasingly urgent clinical danger. The aim of this study was to characterize the carbapenemases and ESBLs in carbapenem-non-susceptible (CNS) Enterobacter cloacae (E. cloacae) isolates from a Chinese teaching hospital. A total of 986 non-duplicated E. cloacae isolates collected between September 2009 and February 2012 were analyzed via antimicrobial susceptibility testing. Carbapenemase and ESBL genes were examined using PCR amplification and DNA sequencing. Clonal relatedness was investigated by pulsed-field gel electrophoresis (PFGE) and dendrogram analysis. We demonstrated that CNSs were prevalent (35/986, 3.55%) in E. cloacae. Phenotypes of carbapenemases and ESBLs were respectively found in 9 (25.7%) and 23 (65.7%) of the 35 CNS E. cloacae strains. KPC-2, IMP-8, IMP-26, NDM-1, TEM-6, CTX-M-3′, CTX-M-14′ and SHV-12 type β-lactamases were identified in 3 (8.6%), 5 (14.3%), 1 (2.9%), 1 (2.9%), 13 (37.1%), 9 (25.7%), 8 (22.9%) and 9 (25.7%) isolates, respectively. Importantly, multiple resistance genes were found to be co-expressed in the same CNS E. cloacae isolates. PFGE and dendrogram analysis showed clonal diversity among these isolates. Our study suggested that over-production of carbapenemases and ESBLs contributed together to the CNS of E. cloacae in China. Furthermore, the decreased susceptibility to carbapenems in E. cloaca in the hospital might arise via stepwise accumulations of multiple drug-resistance determinants in different clones. The prevalence of CNS E. cloacae isolates was not caused by clonal dissemination. Most importantly, we identified a CNS E. cloacae isolate co-expressing IMP-26 and NDM-1, which is the first reported to the best of our knowledge. This is also the first report of NDM-1-producing Enterobacteriaceae in mainland China.     

Emergence and spread of carbapenem-resistant Acinetobacter baumannii sequence type 191 in a Korean hospital

Emergence and spread of specific carbapenem-resistant Acinetobacter baumannii (CRAB) clones cause a serious therapeutic problem. This study was aimed to investigate the clonal diversity and genetic basis of antimicrobial resistance among the 69 CRAB isolates from 2009 to 2010 in a Korean hospital. All CRAB isolates were found to be sequence type (ST) 2 using the Institute Pasteur’s multilocus sequence typing (MLST) scheme, but classified into two sequence groups and nine pulsotypes. Fifty-six CRAB isolates belonging to two main pulsotypes were found to be ST191 using the Bartual’s MLST scheme. All CRAB isolates showed an extensively drug-resistant phenotype. The bla_OXA-51/bla_OXA-23, bla_AmpC/bla_PER-1 and armA genes were largely responsible for resistance to carbapenems, extended-spectrum β-lactams and aminoglycosides, respectively. The first CRAB strains identified in 2005 in this hospital were found to be ST2 using the Institute Pasteur’s MLST scheme, but showed ST353 using the Bartual’s MLST scheme and different pulsotypes from the CRAB isolates from 2009 to 2010. In conclusion, this is the first report of emergence and spread of A. baumannii ST191 in Korea, as well of the genetic basis of its antimicrobial resistance.     

2011年第四季度天津市细菌耐药性监测

目的 建立天津市细菌耐药监测网(TJARSN),了解天津市细菌耐药现状,为卫生行政部门制定抗菌药物政策,指导临床抗菌药物合理应用提供依据.方法 选择天津市有代表性的22所三级和区县级医院,药敏测定采用自动化方法,收集2011年第四季度临床分离细菌情况,以WHONET5.4软件进行数据分析,药敏判断采用CLSI 2008年标准.结果 共分离细菌15880株,革兰阳性菌4376株占27.6％,葡萄球菌属为主要菌属,共分离出2724株占62.2％;肠球菌属997株占22.8％;链球菌属575株占13.1％;革兰阴性菌11 504株占72.4％,排第1位是肺炎克雷伯菌2507株占21.8％,其后依次为大肠埃希菌、铜绿假单胞菌,分别为占21.6％、14.2％;耐甲氧西林金黄色葡萄球菌( MRSA)与耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)检出率分别为38.8％和71.1％;非颅内感染肺炎链球菌对青霉素不敏感率成人(18.7％)低于儿童(43.8％),对左氧氟沙星耐药率成人与儿童均＜5.0％,对大环内酯类耐药率为85.3％～99.1％,对万古霉素无耐药;肠球菌属中已出现对糖肽类耐药株,粪肠球菌和屎肠球菌对万古霉素耐药率分别为0.4％和3.6％,对替考拉宁的耐药率分别为1.1％和4.6％;大肠埃希菌对喹诺酮类药物耐药率约53.0％,大肠埃希菌、肺炎克雷伯菌产超广谱β内酰胺酶检出率分别为34.4％和19.7％,肠杆菌科细菌对碳青霉烯类抗菌药物仍高度敏感,总耐药率＜1.0％;铜绿假单胞菌和鲍氏不动杆菌对亚胺培南和美罗培南耐药率分别为20.1％和18.6％、18.9％和19.9％.结论 初步建立了天津市细菌耐药监测网,以了解天津市临床分离菌株及细菌耐药现状;细菌耐药呈增长趋势,细菌耐药监测工作应引起足够的重视.