大肠埃希菌AmpC酶及ESBLs检测与耐药性分析

目的了解重庆医科大学第二临床学院2003年1～12月分离191株大肠埃希菌产AmpC酶和超广谱β-内酰胺酶（ESBLs）及对常用抗生素的耐药情况，揭示其主要耐药机制，指导临床合理用药。方法采用头孢西丁和头孢曲松改良酶提取物三维试验法，对191株大肠埃希菌分别进行AmpC和ESBLs测定。结果大肠埃希菌单产AmpC酶、ESBLs、同时产AmpC酶＋ESBLs检出率分别为1．1％、23．0％、2．6％。产酶菌株（单产AmpC酶、ESBLs及同时产AmpC酶＋ESBLs）对18种抗生素，除亚胺培南全部敏感外耐药率均高于平均水平。结论大肠埃希菌对头孢菌素类抗生素耐药的主要原因是产生AmpC酶和ESBLs，对产酶菌株临床经验用药只可选用碳青霉烯类抗生素。     

生物被膜大肠埃希菌AmpC酶、超广谱β-内酰胺酶的检测

目的探讨大肠埃希菌生物被膜(biofilm,BF)的耐药情况,为临床合理应用抗生素提供理论依据。方法应用改进的平板培养法建立大肠埃希菌BF模型,用银染法和扫描电镜观察鉴定。采用改良三维试验法检测超广谱β-内酰胺酶(ESBLs)及AmpC酶。结果浮游大肠埃希菌(A组)单产AmpC,单产ESBLs酶及同时产ESBLs和AmpC酶的菌株分别为5.0%(2/40)、30.0%(12/40)和12.5%(5/40);BF大肠埃希菌(B组)单产AmpC酶,单产ESBLs及同时产ESBLs和AmpC酶的菌株分别为10.0%(4/40)、45.0%(18/40)和22.5%(9/40)。对A组和B组的检出率两两分别进行χ2检验,结果均为P<0.05。产酶有BF大肠埃希菌对10种抗生素(除亚胺培南全部敏感外)的耐药率均较高。结论BF的形成和产生ESBLs及AmpC酶的协同作用是大肠埃希菌耐药的主要原因之一。     

Dissemination and diversity of metallo-beta-lactamases in Latin America: report from the SENTRY Antimicrobial Surveillance Program

Carbapenem resistance among Pseudomonas aeruginosa and Acinetobacter spp. is becoming a critical therapeutic problem worldwide. The SENTRY Antimicrobial Surveillance Program monitors pathogen frequency and antimicrobial resistance patterns of nosocomial and community-acquired infections through sentinel hospitals on five continents. Pseudomonas spp. and Acinetobacter spp. strains resistant to imipenem (MIC, ≥16 mg/l), meropenem (MIC, ≥16 mg/l), and ceftazidime (MIC, ≥32 mg/l) collected from January 2001 to December 2003 were routinely screened for antimicrobial resistance genes. Resistant isolates were initially tested for metallo-β-lactamase (MβL) production by phenotypic tests (disk approximation or MβL Etest strip) and then characterization of the MβL (hydrolysis assays, PCR for bla_IMP, bla_VIM, bla_SPM, gene sequencing). Eighty-nine isolates (33 Acinetobacter spp., 54 Pseudomonas aeruginosa, and 2 P. fluorescens) had positive phenotypic screening tests. Among those, 34 isolates producing MβL were identified, including 7 Acinetobacter spp., 25 P. aeruginosa and 2 P. fluorescens. The MβLs identified were IMP-1, VIM-2 and two newly described enzymes: SPM-1 and IMP-16. The greatest concentration of MβL strains was in Brazil, where imipenem-resistant P. aeruginosa increased significantly in the time period evaluated by the SENTRY Program. MβL-producing P. aeruginosa was detected in São Paulo (SPM-1) and Brasilia (SPM-1 and IMP-16), Brazil and Caracas, Venezuela (VIM-2); while MβL-producing Acinetobacter spp. isolates were detected in São Paulo, Brazil (IMP-1). P. fluorescens isolates producing IMP-1 and VIM-2 were detected in São Paulo, Brazil and Santiago, Chile, respectively. The emergence and dissemination of mobile MβL-producing isolates represent an alarming factor for increasing resistance to carbapenems in several medical centres evaluated by the SENTRY Program in Latin America.     

Assessment of pathogen occurrences and resistance profiles among infected patients in the intensive care unit: report from the SENTRY Antimicrobial Surveillance Program (North America, 2001)

Originating from 25 selected intensive care units (ICUs) in North America, a total of 1,321 bacterial strains from blood, respiratory tract, urine and wound sites were processed at a central laboratory as part of the SENTRY Antimicrobial Surveillance Program (2001) to assess their occurrence rates and antimicrobial susceptibility profiles. The rank order of pathogens recovered was Staphylococcus aureus (24.1%), Pseudomonas aeruginosa (12.2%), Escherichia coli (10.1%), Klebsiella spp. (8.9%), Enterococcus spp. (7.2%), coagulase-negative staphylococci (7.0%) and Enterobacter spp. (7.0%). Although oxacillin resistance among S. aureus was 51.4%, no resistance was detected to vancomycin, linezolid and quinupristin/dalfopristin. The most active agents tested against P. aeruginosa were amikacin, cefepime, tobramycin, meropenem and piperacillin/tazobactam (3.1-13.0% resistance). Among agents tested against the Enterobacteriaceae, amikacin, cefepime, imipenem and meropenem showed greatest in vitro activity (0.0-3.4% resistance). Extended-spectrum beta-lactamase-producing phenotype rates were 11.2 and 16.2% in E. coli and Klebsiella spp., respectively. Linezolid was most active against enterococci (1.1% resistance; G2576U ribosomal mutation) whereas 28.4% of isolates were resistant to vancomycin. Cefepime and the carbapenems (imipenem or meropenem) for Gram-negative isolates and linezolid for Gram-positive isolates, provided the broadest spectrum of in vitro activity against contemporary ICU pathogens in North America.     

尿液标本中大肠埃希菌的耐药性分析及其产超广谱β-内酰胺酶监测

目的分析清远地区2003年9月至2004年4月间门诊住院患者尿液标本中大肠埃希菌的耐药性及其产超广谱β-内酰胺酶(ESBLs)情况,以便更好地指导临床用药。方法应用微生物分析系统MicroScanAutoScan-4进行鉴定,并用仪器专家系统判断可疑ESBLs菌株,用纸片扩散法表型确证试验检测ESBLs。结果尿液标本中的大肠埃希菌对亚胺培南、哌拉西林/三唑巴坦、头孢西丁的耐药性最低,分别为3%、5%、8%,而对氨苄西林/舒巴坦、头孢噻吩、哌拉西林的耐药性均>70%,产ESBLs的大肠埃希菌对亚胺培南、哌拉西林/三唑巴坦、头孢西丁的耐药性均<10%,对氨苄西林、氨苄西林/舒巴坦、头孢噻吩、环丙沙星均表现出很强的耐药性。结论尿路感染应根据抗生素敏感试验选择敏感药物进行合理用药并检测相应的产ESBLs情况。     

Salmonella bloodstream infections: report from the SENTRY Antimicrobial Surveillance Program (1997-2001)

Salmonella spp. are significant bloodstream pathogens and are routinely monitored for antimicrobial resistance by the SENTRY Antimicrobial Surveillance Program. Six hundred and one bloodstream infection (BSI) isolates of Salmonella spp., collected over a 5-year period (1997-2001) were tested for their susceptibility against 20 antimicrobial agents, comparing year and geographical region. Salmonella enterica serotype Typhi was the most frequently identified 'species' (43% of identified strains), although 'unspeciated' strains predominated overall (54.2%). The rank order for six selected drugs tested by their MIC(90) values and percentage susceptibility was: ceftriaxone (< or =0.25 mg/l; 99.5% susceptible)>ciprofloxacin (0.12 mg/l; 99.3%)> trimethoprim/sulphamethoxazole (< or =0.5 mg/l; 92.7%)>amoxycillin/clavulanate (16 mg/l; 89.7%)>ampicillin (>16 mg/l; 81.0%)>tetracycline (>8 mg/l; 79.4%). Most isolates remained highly susceptible to all 20 agents examined, with the exception of Salmonella Typhimurium (only 35.3% susceptible to tetracycline, 41.2% to ampicillin, and 61.8% to amoxycillin/clavulanate). DT104 resistance phenotypes were noted in 3.4 and nearly 60.0% of unspeciated Salmonella and S. Typhimurium, respectively. Unexpectedly, the highest overall susceptibility rates were recorded in Latin America. Fluoroquinolone resistance was observed and nalidixic acid screening MICs (< or =8 mg/l) predicted full susceptibility to ciprofloxacin. Five-year results from the SENTRY Program show no clear trend toward greater resistances in Salmonella spp. BSIs for the commonly used antimicrobial classes. With the exception of S. Typhimurium DT104, most Salmonella spp. remain highly susceptible to the tested antimicrobials that maybe utilized for Salmonella BSI.     

Antibiotic resistance in Escherichia coli outpatient urinary isolates: final results from the North American Urinary Tract Infection Collaborative Alliance (NAUTICA)

The North American Urinary Tract Infection Collaborative Alliance (NAUTICA) study determined the antibiotic susceptibility to commonly used agents for urinary tract infections of outpatient Escherichia coli urinary isolates obtained from various geographic regions in the USA and Canada. NAUTICA involved 40 medical centres (30 from the USA and 10 from Canada). From April 2003 to June 2004 inclusive, each centre submitted up to 50 consecutive outpatient midstream urine isolates. All isolates were identified to species level by each laboratory's existing protocol. Susceptibility testing was determined using the Clinical and Laboratory Standards Institute (CLSI) microdilution method. Ampicillin (resistant ≥32 μg/mL), sulphamethoxazole/trimethoprim (SMX/TMP) (resistant ≥4 μg/mL), nitrofurantoin (resistant ≥128 μg/mL), ciprofloxacin (resistant ≥4 μg/mL) and levofloxacin (resistant ≥8 μg/mL) resistance breakpoints used were those published by the CLSI. Of the 1142 E. coli collected, 75.5% (862) were collected from the USA and 280 (24.5%) were from Canada. Patient demographics revealed a mean age of 48.1 years (range, 2 months to 99 years), with female patients representing 79.4% of patients and males representing 20.6%. Overall, resistance to ampicillin was 37.7%, followed by SMX/TMP (21.3%), nitrofurantoin (1.1%), ciprofloxacin (5.5%) and levofloxacin (5.1%). Resistance rates for all antimicrobials were higher in US medical centres compared with Canadian centres (P < 0.05). Fluoroquinolone resistance was highest in patients ≥65 years of age (P < 0.05). Resistance rates demonstrated considerable geographic variability both in the USA and Canada. This study reports higher rates of antibiotic resistance in US versus Canadian outpatient urinary isolates of E. coli and demonstrates the continuing evolution of resistance to antimicrobial agents.     

Activity of tigecycline against clinical isolates of Staphylococcus aureus and extended-spectrum beta-lactamase-producing Escherichia coli in Granada, Spain

We evaluated the in vitro activity of tigecycline using the Etest and disk diffusion method according to Clinical and Laboratory Standards Institute guidelines against clinical isolates of methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) as well as for CTX-M-9 extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and SHV ESBL-producing E. coli. All isolates were susceptible to tigecycline according to US Food and Drug Administration cut-off points. There were no differences in the activity of tigecycline between MSSA and MRSA isolates or between the presence of either type of ESBL. For each type of microorganism studied, we established the equation relating the minimum inhibitory concentration to the diameter of the zone of inhibition.     

Prevalence and antimicrobial susceptibility patterns among gastroenteritis-causing pathogens recovered in Europe and Latin America and Salmonella isolates recovered from bloodstream infections in North America and Latin America: report from the SENTRY Antimicrobial Surveillance Program (2003)

Gastroenteritis-causing pathogens are the second leading cause of morbidity and mortality worldwide. Complicating the clinical diarrhoea syndrome is the emergence of antimicrobial resistance among the responsible bacterial pathogens. The reported increases in fluoroquinolone resistance in Salmonella, Shigella and Campylobacter have been extremely worrisome considering the primary role of ciprofloxacin as a treatment. In this study, 1479 bacterial isolates from gastroenteritis infections were collected in Europe and Latin America, which included Salmonella spp. (834; 56%), Shigella spp. (311; 21%), Campylobacter spp. (182; 12%) and Aeromonas spp. (72; 5%). The fluoroquinolones displayed the greatest activity against these pathogens, with only three non-Campylobacter spp. strains being non-susceptible using current Clinical and Laboratory Standards Institute (CLSI) breakpoint criteria. Whilst ciprofloxacin resistance in European and Latin American Salmonella was only 0.2% and 0.0%, respectively, a total of 16.2% and 12.9% of isolates were resistant to nalidixic acid, indicating possible first-step gyrA mutations. Among confirmed extended-spectrum beta-lactamase-producing Salmonella strains, CTX-M genes were detected in 15 originating from Russia. Erythromycin and azithromycin were the most potent agents tested against Campylobacter spp. (values of minimum inhibitory concentration for 90% of the organisms, 0.5 mg/L and 0.12 mg/L, respectively), with erythromycin displaying the highest susceptibility (91.1%). Salmonella isolates from bloodstream infections displayed antibiograms that were nearly identical to strains causing gastroenteritis. Considering the role that antimicrobial therapy plays in the management of moderate to severe bacterial gastroenteritis, global surveillance and local/national public health programmes can provide critical data illuminating the dissemination of resistance and guidance for empirical therapy.     

Prevalence,Antimicrobial Resistance,and Whole Genome Sequencing Analysis of Shiga Toxin-Producing Escherichia coli (STEC) and Enteropathogenic Escherichia coli (EPEC) from Imported Foods in China during 2015–2021

Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic Escherichia coli (EPEC) are foodborne pathogens that cause hemolytic uremic syndrome and fatal infant diarrhea, respectively, but the characterization of these bacteria from imported food in China are unknown. A total of 1577 food samples from various countries during 2015–2021 were screened for STEC and EPEC, and the obtained isolates were tested for antimicrobial resistance and whole genome sequencing analysis was performed. The prevalence of STEC and EPEC was 1.01% (16/1577) and 0.51% (8/1577), respectively. Antimicrobial resistances to tetracycline (8%), chloramphenicol (8%), ampicillin (4%), ceftazidime (4%), cefotaxime (4%), and trimethoprim-sulfamethoxazole (4%) were observed. The antimicrobial resistance phenotypes corresponded with genotypes for most strains, and some resistance genes were related to mobile genetic elements. All 16 STEC isolates were eae negative, two solely contained stx1 (stx1a or stx1c), 12 merely carried stx2 (stx2a, stx2d, or stx2e), and two had both stx1 and stx2 (stx1c + stx2b, stx1a + stx2a + stx2c). Although they were eae negative, several STEC isolates carried other adherence factors, such as iha (5/16), sab (1/16), and lpfA (8/16), and belonged to serotypes (O130:H11, O8:H19, and O100:H30) or STs (ST297, ST360), which have caused human infections. All the eight EPEC isolates were atypical EPEC; six serotypes and seven STs were found, and clinically relevant EPEC serotypes O26:H11, O103:H2, and O145:H28 were identified. Two STEC/ETEC (enterotoxigenic E. coli) hybrids and one EPEC/ETEC hybrid were observed, since they harbored sta1 and/or stb. The results revealed that food can act as a reservoir of STEC/EPEC with pathogenic potential, and had the potential ability to transfer antibiotic resistance and virulence genes.     

Age-related trends in pathogen frequency and antimicrobial susceptibility of bloodstream isolates in North America: SENTRY Antimicrobial Surveillance Program, 1997-2000

We report age-related trends in pathogen frequency and antimicrobial susceptibility from 25,745 bloodstream infections (BSI) due to bacterial pathogens reported from medical centres participating in the North American SENTRY Antimicrobial Surveillance Program between January 1997 and September 2000. Staphylococcus aureus, Escherichia coli and coagulase-negative staphylococci (CoNS) were the most common pathogens, together accounting for 55% of all BSI pathogens during this time period. Among nosocomial BSI, CoNS were the most frequently isolated pathogens in infants less than 1 year of age, but S. aureus increased in frequency with increasing age. Among community-onset BSI pathogens, Streptococcus pneumoniae was the most frequently reported pathogen causing BSI in patients aged 1–5, S. aureus among those aged 6–64, and E. coli predominated at the extremes of age (less than 1 year and ≥65 years of age). Among key organism: antimicrobial agent combinations evaluated, oxacillin resistance in S. aureus increased with increasing age; conversely, oxacillin resistance among CoNS was highest among children 5 years of age or younger. Penicillin resistance among S. pneumoniae BSI was highest in children younger than 5 years, while vancomycin resistance among Enterococcus spp. predominated among nosocomial BSI in patients over 50 years of age. Important age-related differences exist in species distribution and antimicrobial susceptibility of pathogens causing BSI. This information should be helpful for clinicians as they consider empirical antimicrobial therapy for patients with suspected BSI across the age continuum.     

动物及健康人肠道共生的大肠埃希菌耐药性及产生原因分析

目的了解目前动物和人肠道共生的大肠埃希菌耐药性,分析其产生的原因。方法从甘肃、湖北、北京、山东、四川等地相对封闭的养殖场及养殖场附近的健康人群采集鸡、猪、鱼、人粪便样本,分离大肠埃希菌。用AP I20E鉴定条鉴定怀疑为大肠埃希菌的菌种,采用KB纸片法检测生化鉴定为大肠埃希菌的菌株的耐药性,利用WHONET 5.3软件进行药敏试验数据分析。用脉冲场凝胶电泳技术检测具有相似耐药谱型的大肠埃希菌菌株间的同源性。结果①共收集571株大肠埃希菌,其中从海水养殖鱼类和淡水养殖鱼类分离31株,另从海水养殖鱼类和淡水养殖鱼类分离嗜水气单胞菌株57株;②来源鸡的大肠埃希菌对所有检测的抗菌药物的耐药率最高;③除β-内酰胺类抗生素和阿米卡星外,鸡、猪和人来源菌株的耐药率表现为高、中、低现象,对老的一些抗菌药物和喹诺酮类抗菌药物尤其明显;不同地区分离株的耐药性也有较大的差异;④本次调查首次在国内养鸡场发现产ESBL大肠埃希菌,并且非常多见;⑤嗜水气单胞菌和大肠埃希菌的耐药性有较大的差异,47株耐药谱型相近的菌株中发现了三组基因水平同源性菌株(相似度大于95%)。结论①从不同地区、不同种类动物分离菌株的耐药性不同,与抗生素的使用情况相关。目前我国家禽养殖业滥用喹诺酮类和β-内酰胺类尤其是三代头孢菌素类抗生素的现象较为普遍,应该加以严格控制;②不同菌种的生物学特性不同,导致耐药性不同;③同源性分析发现耐药菌株可在同一种类动物间传播,不同类动物的大肠埃希菌之间可能存在耐药基因的水平传播;④应当加强养殖动物分离的大肠埃希菌耐药性监测。     

阿奇霉素对生物被膜菌产AmpC酶、超广谱β-内酰胺酶的影响

目的探讨生物被膜(biofilm,BF)菌的耐药机制及阿奇霉素对BF菌产AmpC酶、超广谱β-内酰胺酶(extended-spectrumβ-lactamases,ESBLS)的影响。方法应用改进的平板培养法建立大肠埃希菌BF模型,扫描电镜鉴定细菌BF。采用改良三维试验法检测ESBLS及AmpC酶。结果浮游大肠埃希菌(A组)单产AmpC,单产ESBLS酶及同时产ESBLS和AmpC酶的菌株分别占总菌株的5.0%(2/40)、20.0%(8/40)、5.0%(2/40);BF大肠埃希菌(B组)产酶菌株分别占总菌株的15.0%(6/40)、47.5%(19/40)、22.5%(9/40);阿奇霉素诱导BF菌(C组)产酶菌株分别占总菌株的7.5%(3/40)、25%(10/40)、12.5%(5/40)。对A组和B组、B组和C组的检出率两两分别进行χ2检验,结果均为P<0.05。结论阿奇霉素能够明显抑制BF大肠埃希菌产生ESBLS及AmpC酶。     

(His)6-Arg-Arg-人胰岛素原在大肠杆菌中的高效表达

为了提高胰岛素原的表达量，用pQE-40质粒构建了(His)6-Arg-Arg-人胰岛素原[(His)6-Arg-Arg- human Proinsulin，RRhPI]的大肠杆菌表达系统。通过培养条件的优化，在摇瓶培养的条件下，目标产物：RRhPI以包涵体形式获得了高效表达，每升培养基收获湿菌体约27g，包涵体6g(干重1．8g)，RRhPI约540mg。该水平已超过现有文献报道的摇瓶培养的最高水平。     

尿液标本中大肠埃希菌耐药基因BlaKPC-2及BlaNDM-5检测及耐药性分析

目的：分析尿液标本中大肠埃希菌耐药基因BlaKPC-2及BlaNDM-5表达情况并分析其耐药性。方法：所有菌株均参照2011年美国临床实验室标准化研究所纸片扩散法对21种抗菌药物耐药性结果进行检测判读；采用PCR法检测BlaKPC-2及BlaNDM-5基因表达情况；分析耐药基因BlaKPC-2及BlaNDM-5与耐药性的关系。结果：在全部送检的样本中普外科、肾脏病科及呼吸科送检的大肠埃希菌占比较高，大肠埃希菌耐药株共336例，占96.00%；自2015-2017年某院大肠埃希菌检出构成比呈逐年降低趋势；BlaKPC-2阳性大肠埃希菌百分比15.43%，BlaNDM-5阳性大肠埃希菌百分比8.86%；BlaKPC-2阳性及BlaNDM-5阳性大肠埃希菌百分比均逐年降低；BlaKPC-2阳性大肠埃希菌对哌拉西林、头孢吡肟、头孢噻肟、头孢他啶、头孢呋辛钠、头孢克洛、头孢唑啉、舒巴坦、他唑巴坦、阿米卡星、环丙沙星、诺氟沙星、萘啶酸及左旋氧氟沙星的耐药率明显高于BlaKPC-2阴性大肠埃希菌，且差异有显著性（P<0.05）；BlaNDM-5大肠埃希菌对头孢吡肟、头孢噻肟、头孢他啶、头孢呋辛钠、头孢克洛、头孢唑啉、他唑巴坦及阿米卡星的耐药率均显著高于阴性大肠埃希菌，且差异有显著性（P<0.05）。结论：治疗后BlaKPC-2及BlaNDM-5阳性表达与其耐药密切相关，且表达阳性菌耐药率多高于阴性菌。     

不同感染途径CREC分子分型特点及耐药分析#br#

目的 探讨我院不同感染途径耐碳青霉烯大肠埃希菌(carbapenem-resistant Escherichia coli, CREC)分子分型特点以及耐药情况,为临床预防和治疗提供依据。方法 收集我院2017年9月—2018年12月间不同感染途径获得的CREC共14株;菌株鉴定及药敏采用VITEK2-Compact全自动细菌鉴定/药敏系统,联合纸片扩散法(KB法)、E-Test方法进行药敏试验;用PCR技术分别对碳青霉烯类耐药基因(blaKPC、blaNDM、blaIMP、blaVIM和blaOXA-48)、超广谱β-内酰胺酶基因(blaSHV、blaTEM、blaCTX和blaOXA-1)、AmpC酶耐药基因(blaFOX、blaMOX和blaDHA)、膜孔蛋白基因(ompk35和ompk36)进行检测,同时进行质粒接合试验,掌握我院CREC耐药基因分布及流行情况;采用PFGE对14株不同感染途径CREC进行同源性分析,分析我院CREC分子流行特点。结果 临床资料：14株CREC主要来自重症医学科,占57.14%(8/14);痰标本检出5株,尿标本检出4株,血液标本检出2株,灌洗液、脑脊液、导管尖端各检出1株。耐药基因检出情况：14株CREC有12株携带blaNDM-5、1株携带blaKPC-2和1株携带blaNDM-1;我院CREC通常携带blaNDM-5以及ESBLs耐药基因,并伴有ompk36基因的缺失。接合试验结果：仅1株CREC接合试验成功。PFGE分型结果：14株CREC分为4个PFGE分型,其中PT03为优势型别,包含11株菌。菌株耐药情况：CREC耐药情况十分严重,对单环β-内酰胺类、头孢类、左氧氟沙星、碳青霉烯类药物均表现耐药;而对氨基糖苷类以及磺胺类药物也达到92.86%的耐药率;对替加环素和多黏菌素均表现为敏感。结论 我院CREC主要来自呼吸道标本,且存在克隆的流行,其优势型别的菌株多携带blaNDM-5以及ESBLs耐药基因,并伴有Ompk36基因的缺失,且表现对多种抗生素呈高度耐药,提示我们应加大对CREC的管控,需密切监测并采取控制措施,阻断CREC在院内的传播和暴发。     

Pathogen occurrence and antimicrobial resistance trends among urinary tract infection isolates in the Asia-Western Pacific Region: report from the SENTRY Antimicrobial Surveillance Program, 1998-1999

Worldwide surveillance of antimicrobial resistance among urinary tract pathogens is useful to determine important trends and geographical variation for common Gram-positive and -negative species. The most common causative uropathogens often have intrinsic or acquired resistance mechanisms which include ESBL production among enteric bacilli, multi-drug resistant staphylococci and non-fermentative Gram-negative bacilli such as Pseudomonas aeruginosa and Acinetobacter spp. and vancomycin-resistant Enterococcus spp. This study evaluates pathogen frequency and the resistance rates among urinary tract infection (UTI) pathogens in 14 medical centres in the Asia-Pacific region between 1998 and 1999. The isolates were referred to a central monitor for reference NCCLS broth microdilution testing, identification confirmation and patient demographic analysis. Over 50% of the 958 pathogens were Escherichia coli and Klebsiella spp. followed by P. aeruginosa, Enterococcus spp. and Enterobacter spp. Susceptibility for the three enteric bacilli was high for carbapenems (100%), 'fourth-generation' cephalosporins (cefepime 94.9-98.6%) and amikacin (> or = 93.0%). Beta-lactamase inhibitor compounds were more active against E. coli (piperacillin/tazobactam; > 90% susceptible) than the other two enteric species and all other tested agents had a narrower spectra of activity. The rank order of anti-pseudomonal agents was amikacin (91.5% susceptible)> imipenem > piperacillin/tazobactam > tobramycin > ceftazidime and cefepime (77.4 and 76.4% susceptible, respectively). Susceptibility to quinolones for the P. aeruginosa isolates was only 63.2-67.0%. Only one vancomycin-intermediate Enterococcus spp. (van C phenotype) was detected among the 103 strains tested. Newer fluoroquinolones (gatifloxacin; MIC(50), mg/l) were more potent against enterococci than ciprofloxacin (MIC(50), 2 mg/l) and high-level resistance to aminoglycosides was common (41.7%). The data presented are compared to studies of similar design from other areas which are part of the SENTRY surveillance network.     

不同感染途径CREC分子分型特点及耐药分析#br#

目的 探讨我院不同感染途径耐碳青霉烯大肠埃希菌(carbapenem-resistant Escherichia coli, CREC)分子分型特点以及耐药情况,为临床预防和治疗提供依据。方法 收集我院2017年9月—2018年12月间不同感染途径获得的CREC共14株;菌株鉴定及药敏采用VITEK2-Compact全自动细菌鉴定/药敏系统,联合纸片扩散法(KB法)、E-Test方法进行药敏试验;用PCR技术分别对碳青霉烯类耐药基因(blaKPC、blaNDM、blaIMP、blaVIM和blaOXA-48)、超广谱β-内酰胺酶基因(blaSHV、blaTEM、blaCTX和blaOXA-1)、AmpC酶耐药基因(blaFOX、blaMOX和blaDHA)、膜孔蛋白基因(ompk35和ompk36)进行检测,同时进行质粒接合试验,掌握我院CREC耐药基因分布及流行情况;采用PFGE对14株不同感染途径CREC进行同源性分析,分析我院CREC分子流行特点。结果 临床资料：14株CREC主要来自重症医学科,占57.14%(8/14);痰标本检出5株,尿标本检出4株,血液标本检出2株,灌洗液、脑脊液、导管尖端各检出1株。耐药基因检出情况：14株CREC有12株携带blaNDM-5、1株携带blaKPC-2和1株携带blaNDM-1;我院CREC通常携带blaNDM-5以及ESBLs耐药基因,并伴有ompk36基因的缺失。接合试验结果：仅1株CREC接合试验成功。PFGE分型结果：14株CREC分为4个PFGE分型,其中PT03为优势型别,包含11株菌。菌株耐药情况：CREC耐药情况十分严重,对单环β-内酰胺类、头孢类、左氧氟沙星、碳青霉烯类药物均表现耐药;而对氨基糖苷类以及磺胺类药物也达到92.86%的耐药率;对替加环素和多黏菌素均表现为敏感。结论     

近3年分离大肠埃希菌耐药性的分析

目的 了解我院2014年1月1日-2016年12月31日3年间分离的1584株大肠埃希菌耐药性,指导临床用药。方法 常规培养分离细菌,用法国梅里埃Vitek2-CompactT全自动鉴定药敏分析仪及配套试剂。结果 1584株大肠埃希菌中来自尿液710株(44.8%);血液197株(12.4%);分泌物193株(12.1%);痰液169株(10.6%);胸腹水30株(1.9%)。其科室分布列前3位的分别为：泌尿外科326株(22.4%);肾内科180株(11.4%);重症监护室(ICU)165株(10.4%)。3年间产ESBLs大肠埃希菌的检出率分别为63.9%、58.7%和60.5%。产ESBLs大肠埃希菌对大多数抗菌药物的耐药率明显高于非产ESBLs大肠埃希菌,其对临床常用抗菌药物的耐药率呈逐年上升趋势,2016年发现3株对亚胺培南耐药的大肠埃希菌。结论 产ESBLs大肠埃希菌对绝大部分抗生素的耐药率居高不下,应密切关注大肠埃希菌耐药性变迁,防止多重耐药菌株的传播流行。     

质粒介导的喹诺酮耐药基因在中国大陆尿液分离的大肠埃希菌中的广泛分布

目的分析中国大陆20家三甲医院尿来源大肠埃希菌的耐药特点并调查质粒介导的喹诺酮类耐药基因的分布情况和流行特点。方法收集卫生部全国耐药监测网2007年1月至2008年3月非重复298株尿液分离大肠埃希菌;琼脂稀释法测定其对20种抗菌药物的敏感性,多聚酶链反应和DNA测序分析qn-rA,qnrB,qnrS,aac(6’)-ib和qepA基因的流行性;接合实验分析质粒的转移性;Eric-PCR分析喹诺酮基因阳性菌株之间的遗传相关性;卡方检验用于分析耐药基因与氟喹诺酮耐药之间的相关性。结果 298株大肠埃希菌对20种抗菌药物耐药现象严重,其中对环丙沙星和左氧氟沙星有很高的耐药性,耐药率高达78.5%和74.2%。经基因比对分析,62株(20.8%)细菌携带aac(6’)-Ib基因;45株(15.1%)细菌携带喹诺酮耐药基因,1株(0.3%)检测出qnrA基因,3株(11.4%)检出qnrB基因,5株(1.7%)检出qnrS基因,25株(8.4%)确定为aac(6’)-Ib-cr基因,12株(4.7%)检出qepA基因;此外,有3株细菌分别发现aac(6’)-Ib-cr和qepA1基因aac(6’)-Ib-cr和qnrB1基因,qepA和qnrS1基因共存。45株喹诺酮基因阳性菌株之间具有很大的遗传差异,并且其中有16株细菌携带的基因具有可转移性。aac(6’)-Ib的流行性与细菌的环丙沙星和左氧氟沙星不敏感性相关(P<0.05);喹诺酮耐药基因的流行性与细菌的氟喹诺酮不敏感性相关(P<0.05)。结论尿液分离的大肠埃希菌耐药严重,质粒介导的喹诺酮耐药基因主要以aac(6’)-ib-cr为主,qepA1次之,这些潜在播散的喹诺酮耐药基因对于临床尿路感染的治疗有很大的挑战。