泌尿系感染患者病原菌分布及药敏特征分析

目的分析泌尿系统感染病原菌分布及耐药特征,为临床合理使用抗菌药物提供依据。方法对2011-2012年3 879例尿路感染患者尿培养中分离出的病原菌,采用法国生物梅里埃公司VITEK-2全自动细菌鉴定药敏仪和GN鉴定卡进行菌株鉴定,AST-GN16药敏卡进行药敏试验,并对产ESBLs耐药表型的菌株用双纸片法进行确证。结果 3 879份尿培养标本检出病原菌1 066株,检出率为27.5%;其中革兰阴性菌765株占71.8%,革兰阳性菌215株占20.2%,真菌86株占8.0%,检出率最高的前4位病原菌依次为大肠埃希菌、屎肠球菌、肺炎克雷伯菌和粪肠球菌,分别占51.3%、11.3%、7.6%和5.9%;大肠埃希菌和肺炎克雷伯菌产ESBLs检出率分别为64.4%、64.2%,产ESBLs大肠埃希菌和肺炎克雷伯菌对亚胺培南、美罗培南敏感率较高,>99.0%,对其余抗菌药物敏感率较低,<78.0%;肠球菌属耐药增长迅速。结论泌尿系统感染病原菌以革兰阴性菌为主,大肠埃希菌是主要病原菌,产ESBLs菌检出率较高且呈多药耐药特征,临床上应根据药敏结果合理用药。     

Characterization of cephalosporin-resistant clinical Enterobacteriaceae for CTX-M ESBLs in Bahrain

ObjectiveTo detect the presence of specific CTX-M class of extended spectyum β-lactamases (ESBLs) in a collection of cephalosporin-resistant Enterobacteriaceae isolates from Bahrain.MethodsA subset of 80 cephalosporin-resistant Enterobacteriaceae collected from Salmaniya Medical Complex, Bahrain, were characterized further for the presence of specific genogroups of CTX-M β-lactamases by multiplex- and monoplex- PCRs. The primers used for the multiplex and monoplex PCRs were of genogroups- 1, 2, 8, 9 and 25. Sequencing of the representative isolates was performed to find the circulating CTX-M-types.ResultsA total of 93.8% (75/80) isolates showed the amplicons corresponding to any of the genogroups (1, 2, 8, 9, 25) and the remaining 6.2% isolates turned out negative in multiplex PCR. Some of the isolates demonstrated multiple bands corresponding to the sizes of different genogroups. Further confirmation with respective monoplex PCR on these 75 isolates demonstrated that 93.3% (70/75) harbored CTX-M genogroup-1 and 6.7% (5/75) harbored genogroup-9. We did not find the presence of genogroups 2, 8, and 25 in these isolates by monoplex PCR. Sequencing results of genogroup-1 isolates demonstrated the presence of CTX-M-15-like ESBL, however, discrepant results were noticed in genogroup-9 isolates, sequencing showed them as CTX-M-55-like ESBL.ConclusionsThis is the first report from Bahrain characterizing the CTX-M genogroups of ESBLs and reporting the emergence of bla_CTX-M-55-like gene in this region.     

PER extended-spectrum β-lactamases originate from Pararheinheimera spp

To investigate the origin of PER extended-spectrum β-lactamases, publicly available sequence databases were searched for bla_PER-like genes. Three genomes from Pararheinheimera, a genus associated with water and soil environments, were found to carry bla_PER-like genes but lacked the ISCR1/ISPa12/ISPa13 insertion sequences commonly associated with bla_PER in clinical isolates. Sequence analysis revealed 78–96% nucleotide identity and conserved synteny between the clinical mobile genetic elements (MGEs) encoding bla_PER-1 and the bla_PER locus in the Pararheinheimera genomes. Notably, bla_PER genes were only identified in 3 of 21 Pararheinheimera and Rheinheimera genomes, whereas the genetic environment of bla_PER genes as found in clinical MGEs was conserved in all Pararheinheimera and Rheinheimera genomes. These findings indicate that bla_PER genes were likely acquired by a branch of the Pararheinheimera genus long before the antibiotic era. Later, bla_PER genes were mobilised, likely through the involvement of insertion sequences, from one or several Pararheinheimera species, allowing their dissemination into human pathogens.     

Extended-spectrum β-lactamase-producing Enterobacteriaceae,national study of antimicrobial treatment for pediatric urinary tract infection

Objective

To evaluate clinical practices for ESBL-producing urinary tract infection (UTI) in France.

Antimicrobial susceptibility of extended-spectrum beta-lactamase producers and multidrug-resistant Acinetobacter baumannii throughout the United States and comparative in vitro activity of tigecycline, a new glycylcycline antimicrobial

As part of the Tigecycline Evaluation and Surveillance Trial, isolates of Escherichia coli, Klebsiella pneumoniae, and Acinetobacter baumannii were collected in the United States between January 2004 and January 2006. Determinations of antimicrobial susceptibility and extended-spectrum beta-lactamase (ESBL) production were carried out according to the Clinical and Laboratory Standards Institute guidelines. A high percentage of ESBL-producing K. pneumoniae (>or=19.0%) was detected in New Jersey, Massachusetts, New York, and Missouri, and for E. coli, in the District of Columbia (9.5%). Against ESBL-producing isolates, the lowest MIC(90)s were for tigecycline (0.5-2 microg/mL) and imipenem (0.5-8 microg/mL). Overall, 282 (27.5%) A. baumannii isolates were resistant to >or=3 antimicrobial classes. The most common phenotype (33.0%) was resistance to cefepime, ceftazidime, ceftriaxone, levofloxacin, and piperacillin-tazobactam. Against multidrug-resistant A. baumannii, tigecycline and minocycline were the most active agents (MIC(90), 2 and 8 microg/mL, respectively).     

Synergistic and bactericidal activities of mecillinam,amoxicillin and clavulanic acid combinations against extended-spectrum β-lactamase (ESBL)-producing Escherichia coli in 24-h time–kill experiments

This study aimed to evaluate the potential synergistic and bactericidal effects of mecillinam in combination with amoxicillin and clavulanic acid against extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. Eight clinical E. coli isolates with varying susceptibility to mecillinam [minimum inhibitory concentrations (MICs) of 0.125 mg/L to >256 mg/L] and high-level resistance to amoxicillin (MICs > 256 mg/L) were used. Whole-genome sequencing was performed to determine the presence of β-lactamase genes and mutations in the cysB gene. The activities of single drugs and the combinations of two or three drugs were tested in 24-h time–kill experiments. Population analysis was performed for two strains before and after experiments. Only one strain had a mutation in the cysB gene resulting in an amino acid substitution. With the two-drug combinations, initial killing was observed both with mecillinam and amoxicillin when combined with clavulanic acid. Synergy was observed with mecillinam and clavulanic acid against one strain and with amoxicillin and clavulanic acid against three strains. However, following significant re-growth, a bactericidal effect was found only with amoxicillin and clavulanic acid against two strains. Pre-existing subpopulations with elevated mecillinam MICs were detected before experiments and were selected with mecillinam alone or in two-drug combinations. In contrast, the three-drug combination showed enhanced activity with synergy against six strains, a bactericidal effect against all eight strains, and suppression of resistance during 24-h antibiotic exposure. This combination may be of clinical interest in the treatment of urinary tract infections caused by ESBL-producing E. coli.     

Enterobacteriaceae bacteremia: Risk factors for ESBLPE

Objectives

The increasing prevalence of extended spectrum beta-lactamase producing enterobacteriaceae (ESBLPE) requires defining the use of carbapenems in first intention. We analyzed the associations between enterobacteriaceae bacteremia (EbBact) and ESBLPE carriage during 10 years in a 950-bed teaching hospital.

Methods

We analyzed a 10-year (July 2001 to June 2011) prospective collection of bacteremia cases including 2 databases: (1) EbBact and (2) a computerized database of patients carrying EBLSE. Only one episode of EbBact was analyzed per patient and hospital stay. Factors associated with ESBLPE bacteremia were assessed by univariate and multivariate logistic regression analysis.

Results

Overall, 2355 cases of EbBact were identified, among which 135 (5.7%) were ESBLPE (2001–05: 1.4%, 2006–09: 7.6%, 2010–11: 14.2%). ESBLPE bacteremia was observed in 52 of the 88 (59%) patients carrying ESBLPE and in 83/2267 (3.7%) patients not known to be colonized with ESBLPE. Factors associated with ESBLPE bacteremia in patients not known to be colonized were: female gender (ORa = 0.56, CI95% [0.34–0.91]), hospitalization in the ICU (ORa = 2.51 [1.27–5.05]) or medical/surgical wards (ORa = 1.83 [1.04–3.38]), the period (2006–09, ORa = 4.08 [2.21–8.16]; 2010–11, ORa = 8.17 [4.14–17.06] compared to 2001–05), and history of EbBact (ORa = 2.29 [0.97–4.79]).

Conclusion

In case of EbBact, patients known to be colonized with ESBLPE present with ESBLPE bacteremia in more than half of the cases, requiring carbapenems as empirical antibiotic treatment. The global prevalence of ESBLPE among patients presenting with EbBact not known to be colonized with ESBLPE was 3.7%.     

兰州地区呼吸道感染流感嗜血杆菌分布特点及耐药性分析

目的 分析近几年兰州地区呼吸道流感嗜血杆菌感染的人群和季节性分布特点及菌体耐药性.方法 收集2011-2013年兰州市第一人民医院住院急性呼吸道感染病人呼吸道标本,共检出流感嗜血杆菌312株.用K-B法检测药敏结果,头孢硝噻吩纸片检测β-内酰胺酶.将药敏结果用Whonet软件进行分析,得出各种药物流感嗜血杆菌耐药率.结果 流感嗜血杆菌的感染呈现以下特点：明显的季节性,流感嗜血杆菌感染主要集中在11月和12月,占全年感染数的50％以上,10岁以下儿童感染者98％集中在11月或12月;成年人感染流感嗜血杆菌,感染患者年龄50岁以上者占91.4％;细菌耐药性特点：65.4％的分离株产3-内酰胺酶、氨苄西林、氨苄西林/舒巴坦、头孢呋辛、头孢他啶、复方新罗明、氯霉素耐药率依次为66.3％叼1.0％、9.2％～22.8％、17.3％～20.1％、2.0％～4.4％、31.6％～51.7％、16.3％～18.4％,头孢曲松、头孢噻肟、亚胺培南和美罗培南尚未发现耐药株.结论 流感嗜血杆菌的感染呈明显的季节性分布,感染人群主要为婴幼儿及老年人,耐药率呈逐年上升趋势.     

A profile of the GenePOC Carba C assay for the detection and differentiation of gene sequences associated with carbapenem-non-susceptibility

ABSTRACT

The novel GenePOC/Revogene Carba C assay (GenePOC, Québec, Canada; now Meridian Bioscience, Cincinnati, OH, USA) is a CE-IVD marked, FDA-approved qualitative in vitro diagnostic test for the detection of genes associated with carbapenem-non-susceptibility. Colonies of Enterobacterales can be directly tested without prior DNA isolation. The test consists of a fluorescent-based real-time PCR assay that runs on the centripetal micro?uidic revogene platform, providing results within 70 minutes. The assay was evaluated in two studies comprising a total of 294 molecularly characterized clinical Enterobacterales isolates. The overall sensitivity for the detection of carbapenemase gene sequences with the GenePOC assay was 100% (95% CI, 98.4% to 100). Besides the common KPC, VIM, NDM and OXA-48-like carbapenemase genes, also the very variable IMP variants were all detected. The speci?city of the assay was 100% (95% CI, 98.8% to 100%). In this article the performance of the GenePOC/Revogene Carba C assay is evaluated and other currently available methods for the detection of carbapenemases are reviewed.     

转座子tnpU基因在多重耐药革兰阴性杆菌中的分布情况

目的研究转座子tnpU基因和β-内酰胺酶在多重耐药革兰阴性杆菌中的分布情况。方法用纸片扩散初筛试验、扩散确证试验进行超广谱β-内酰胺酶（ESBLs）表型检查,头孢西丁三维试验进行AmpC β-内酰胺酶的表型检查,纸片协同试验筛选产金属β-内酰胺酶（MBL）菌株;用多重聚合酶链反应（PCR）技术扩增转座子tnpU基因,并进行DNA测序;用MIC药敏法分析多重耐药革兰阴性杆菌的药物敏感性。结果转座子tnpU的总检出率为25．5％。在各菌种的检出率分别为大肠埃希菌占6.3％（3株）、肺炎克雷伯菌占8．3％（1株）、鲍曼不动杆菌占33-3％（20株）、铜绿假单胞菌占43．2％（16株）;β-内酰胺酶表型检测中,ESBLs的检出率最高,转座子tnpU基因阳性的菌株大多数B．内酰胺酶表型为阳性;转座子tnpU基因阳性菌株对抗生素的耐药率显著高于转座子阴性菌株（P〈0．05）。结论转座子tnpU基因在非发酵菌中的分布较广泛,可能在多重耐药机制中起重要作用。