产超广谱β-内酰胺酶肺炎克雷伯菌的耐药性分析

肺炎克雷伯菌是医院和社区感染的重要病原菌，近年来因其能产生大量的超广谱p内酰胺酶（ESBLs）而对抗生素的耐药性不断增强，给临床治疗带来困难。2003年3月～2004年3月，我们用纸片协同法检测了87株肺炎克雷伯菌的产ESBLs情况及其耐药性。现报告如下。     

下呼吸道产超广谱β-内酰胺酶肺炎克雷伯氏菌及大肠埃希氏菌的耐药性分析

目的分析临床分离的下呼吸道产超广谱β-内酰胺酶肺炎克雷伯菌及大肠埃希菌的耐药特点,从而掌握耐药菌株的流行状况。方法按常规方法进行细菌分离、培养和菌种鉴定。采用微量液体稀释与K—B法分别对常用抗生素和头孢哌酮／舒巴坦的耐药性进行检测。结果产ESBLs肺炎克雷伯菌和大肠埃希菌对AMP、AMP／SB、PIP、CF、CFZ、CRM、CPD、CAX、CAZ、CTX、CPE和AZT的耐药率高达90％以上;对含β-内酰胺酶抑制剂的复合制剂（PIP／TB和SCF）的耐药率分别是52．6％、34．6％和39．7％、19．8％;对环丙沙星、庆大霉素、妥布霉素的耐药率较高,分别是64％、88．8％,96．2％、75％和96％、87．9％,具有多重耐药特点,但对亚胺培南敏感。结论产ESBLs肺炎克雷伯菌和大肠埃希菌对多种不同种类抗生素耐药,且具有多重耐药的特点。尤其是对青霉素、头孢菌素类耐药率高,但对碳青霉烯类抗生素敏感。     

肺炎克雷伯菌产超广谱β-内酰胺酶检测及耐药性分析

目的探讨产超广谱β-内酰胺酶(ESBLs)肺炎克雷伯菌感染的分布状况及耐药特点。方法对我院临床标本分离出的肺炎克雷伯菌用美国临床实验室标准化委员会(NCCLS)推荐的表型确证法检测ESBLs,K-B纸片琼脂扩散法进行药敏试验。结果肺炎克雷伯菌产ESBLs的检出率为34.4%,其主要以呼吸道感染为主。产ESBLs菌株对亚胺培南耐药率为0。产ESBLs菌株对抗生素的耐药率明显高于非产ESBLs菌株。结论产ESBLs菌对常用抗生素的耐药率明显高于非产ESBLs菌株,碳青霉烯类抗生素亚胺培南是治疗产ESBLs菌株感染的理想药物。     

产超广谱β-内酰胺酶大肠埃希菌和肺炎克雷伯菌的分布及耐药性分析

目的了解医院产超广谱β-内酰胺酶（ESBLs）大肠埃希菌和肺炎克雷伯菌的分布及耐药性特点。方法对我院2004年7月～2006年7月间各类临床标本分离出的大肠埃希菌307株和肺炎克雷伯菌202株，用CLSI／NCCLS推荐的表型确证法检测其ESBLs，采用K-B纸片琼脂扩散法进行药敏试验，分析产ESBLs菌株的分布及耐药性。结果大肠埃希菌和肺炎克雷伯菌产ESBLS菌株的检出率分别为38．4％（118／307）和31．7％（64／202），主要分布于尿和痰、咽拭子中，病区主要集中于肺科、神经外科、感染科、泌尿外科、ICU室。产ESBLs菌株对亚胺培南和美罗培南呈高度敏感，对哌托西林／三唑巴坦、头孢哌酮／舒巴坦、头孢西丁耐药率较低，对其他抗菌药物均出现较高耐药。结论产ESBLS的大肠埃希菌和肺炎克雷伯菌分布在不同病区的不同标本中，碳青霉烯类抗生素亚胺培南和美罗培南是治疗产ESBLS菌株感染的较佳药物。     

产超广谱β内酰胺酶大肠埃希菌和肺炎克雷伯菌的耐药性研究

超广谱β内酰胺酶（ESBLs）主要由肠杆菌科细菌产生,以大肠埃希菌（EF）、肺炎克雷伯菌（KP）为代表。2004年6月～2005年6月,我们对我院临床分离的产ESBLs的EF和KP的耐药情况进行了分析。现报告如下。     

尿路感染患者产超广谱β-内酰胺酶大肠埃希菌的耐药性分析

目的了解尿路感染患者中产超广谱β-内酰胺酶(extended-spectrumβ-lactamase,ESBLs)大肠埃希菌的耐药现状,指导临床合理用药。方法从我院2015年1月—2016年1月间尿路感染患者的尿液中分离出大肠埃希菌株。所有菌株采用法国梅里埃公司VITEK2 Compact分析仪进行细菌鉴定,纸片扩散法检测大肠埃希菌产ESBLs的产生情况及耐药特点。结果从尿路感染患者中共检出大肠埃希菌432株,其中有226株产ESBLs,检出率为52.31%,药物敏感性试验结果显示产ESBLs菌株对亚胺培南耐药率仅为0.88%;其次为呋喃妥因,耐药率为19.91%;耐药率最高的为氨苄西林,为98.23%;对含酶抑制剂的药物其耐药率也明显增加。与非产ESBLs菌株耐药性相比,产ESBLs株的耐药率显著增高。结论尿路感染患者中分离得到产ESBLs大肠埃希菌的比例较高,积极检测和监测产ESBLs大肠埃希菌及其耐药情况对于临床合理用药、院内感染控制及流行病学调查极为重要。     

肺炎克雷伯菌产超广谱β-内酰胺酶研究进展

产超广谱β-内酞胺酶（ESBLs）是肺炎克雷伯菌产生耐药的主要机制。ESBLs大多源于TEM、SHV位的基因突变,由1~4个氨基酸替换而形成新的酶蛋白,它的基因型主要包括TEM、SHV、CTX-M、OXA及其他少见类型,其中以TEM、SHV、CTX-M最常见,并呈全球分布[1]。下面分述ES-BLs的生物学特点。     

大肠埃希菌和肺炎克雷伯菌超广谱β-内酰胺酶基因型及耐药性研究

超广谱β-内酰胺酶（ESBLs）是革兰阴性细菌对新型广谱β-内酰胺类抗生素耐药最重要的机制，主要由大肠埃希菌和肺炎克雷伯菌等肠杆菌科细菌产生。随着第三代头孢菌素在临床上的大量应用，产ESBLs的细菌种类不断增加，ESBLs基因表型也不断增加，成为细菌耐药机制研究的热点。     

产超广谱β-内酰胺酶大肠埃希菌和肺炎克雷伯菌院内感染调查

目的 分析我院产超广谱β-内酰胺酶(ESBLs)大肠埃希菌和肺炎克雷伯菌院内感染情况。方法 调查我院2002年1月～2003年10月产ESBLs大肠埃希菌和肺炎克雷伯菌感染情况，分析其院内感染的特点及相关因素。结果 49例感染产ESBLs大肠埃希菌和肺炎克雷伯菌患者中社区获得性感染8例占16％，院内获得性感染42例占84％，院内感染科室有9个，主要是呼吸科、神经外科、消化科；院内感染部位主要是：呼吸道、泌尿道。院内感染患者100％前期应用抗菌素。结论 社区获得性感染产ESBLs大肠埃希菌和肺炎克雷伯菌患者入院，介入性操作，不合理应用抗菌素与我院产ESBLs大肠埃希菌和肺炎克雷伯菌院内感染有关，为控制其传播，应采取相应的消毒隔离措施，合理使用抗菌素，防止院内感染的暴发和流行。     

浙江省产超广谱β-内酰胺酶大肠埃希菌和肺炎克雷伯菌流行情况及耐药性

目的 调查浙江省产超广谱β-内酰胺酶（ESBLs)的大肠埃希菌（E.coli）和肺炎克雷伯菌（K.pneumoniae）的流行情况及耐药性。方法 收集各地区临床分离的E.coli和K.pneumoniae共362株,经抑制剂增强的肉汤稀释法筛选出产ESBLs细菌,并用浓度梯度法（E-test）检测其对9种抗菌药物的耐药性。结果 浙江省E.coli和K.pneumoniae中ESBLs检出率分别为37.9%和41.2%,总检出率为39.2%。产ESBLs细菌对头孢他啶（CAZ）、头孢噻肟（CTX）、头孢西丁（FOX）、头孢吡肟（FEP）、头孢哌酮/舒巴坦（CFP/SUL）、哌拉西林/他唑巴坦（PZP/TAE）、阿米卡星（AMC）、环丙沙星（CIP）的耐药率比不产酶株都有不同程度地增加,所有菌株对亚胺培南（IMP）都敏感。结论 浙江各地区ESBLs在E.coli和K.pneumoniae中的检出率高。产ESBLs菌对所测试的8种抗菌药物的耐药程度比不产酶株为高,但所有菌株对亚胺培南均敏感。     

产超广谱β内酰胺酶肺炎克雷伯菌医院获得性肺炎临床危险因素分析

目的探讨产超广谱β内酰胺酶(ESBLs)肺炎克雷伯菌医院获得性肺炎的临床危险因素。方法选取2001-07~2004-12武汉大学人民医院收治的肺炎克雷伯菌医院获得性肺炎101例,38例产ESBLs肺炎克雷伯菌医院获得性肺炎作为病例组,63例非产ESBLs肺炎克雷伯菌医院获得性肺炎作为对照组。对产ES-BLs肺炎克雷伯菌肺炎的危险因素进行病例对照研究。结果ESBLs阳性组对12种抗生素的耐药性远远高于ESBLs阴性组。单因素分析发现住院时间大于20d、入住重症监护病房(ICU)、气管插管或切开、留置导管、机械通气、头孢噻肟的使用是产ESBLs肺炎克雷伯菌引起医院获得性肺炎的主要危险因素。多因素非条件lo-gistic回归分析表明,头孢噻肟的使用是产ESBLs肺炎克雷伯菌医院获得性肺炎的独立危险因素。结论长程住院、入住ICU等是ESBLs肺炎克雷伯菌医院获得性肺炎发生的危险因素,尤以头孢噻肟的使用是主要危险因素。     

In vitro activity of antimicrobial agents against extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae at a tertiary care center in Lebanon

Looking for therapeutic options, we assessed the minimum inhibitory concentrations (MICs) of 7 antimicrobial agents against extended-spectrum beta-lactamase-producing Klebsiella pneumoniae (n = 58) and Escherichia coli (n = 84) isolates. High rates of susceptibility were shown for both E coli and K pneumoniae against ertapenem (100% for both), piperacillin/tazobactam (83% and 91%, respectively) and amikacin (96% and 82%, respectively). In addition, most K pneumoniae isolates were susceptible to quinolones (72%-75%) and cefepime (88%). However, clinical correlation is warranted.     

Comparison of Escherichia coli and Klebsiella pneumoniae liver abscesses

BACKGROUND: Escherichia coli and Klebsiella pneumoniae are the most common causative pathogens of pyogenic liver abscesses. The objective of this study was to compare outcome between patients with liver abscesses due to E coli and those with liver abscesses caused by K pneumoniae; we also aimed to identify separately the predictors of mortality in the 2 groups. METHODS: We conducted a retrospective study of 202 patients who presented with pyogenic liver abscesses caused by either E coli or K pneumoniae from July 2000 to June 2005. Outcome of the patients was analyzed by exact logistic regression with adjustment for baseline and clinical covariates. Significant predictors of mortality in the E coli and the K pneumoniae groups were investigated by multivariate analysis of demographic and clinical variables in each group. RESULTS: Of the 202 patients (128 men and 74 women; age range, 19 to 89 years), pyogenic liver abscess was due to E coli infection in 55 patients and K pneumoniae in 147 patients. In contrast to patients with K pneumoniae, patients with E coli liver abscess were more likely to be older and female, have a biliary abnormality or malignancy, pleural effusion, polymicrobial infection with anaerobic or multi-drug-resistant organisms, a higher APACHE II score, and to have been treated initially with ineffective antibiotics; they were also less likely to have diabetes mellitus. The cause of K pneumoniae liver abscess was often cryptogenic. The sensitivity, specificity, positive predictive value, and likelihood ratio of the presence of biliary disorders and coexisting malignancy as a predictive parameter of E coli liver abscess were 25%, 96%, 67%, and 5.45/1, respectively. The sensitivity, specificity, positive predictive value, and likelihood ratio of the presence of diabetes mellitus with an abscess of cryptogenic origin as a predictive parameter of K pneumoniae liver abscess were 39%, 84%, 81%, and 2.36/1, respectively. There was no significant difference in mortality between patients with E coli and those with K pneumoniae infections (26% vs 4%; adjusted OR, 4.2; 95% CI, 0.63 to 27; P = 0.105). However, for patients with liver abscess caused by E coli, the APACHE II score at admission (OR, 1.7; 95% CI, 1.1 to 2.6; P = 0.021), malignancy (OR, 26; 95% CI, 1.8 to 370; P = 0.016), and right-lobe abscess (OR, 0.0029; 95% CI, 0.00010 to 0.15; P = 0.004) were significant predictors of death, whereas uremia (OR, 52; 95% CI, 3.5 to 750; P = 0.004) and multi-drug-resistant isolates (OR, 26; 95% CI, 2.3 to 290; P = 0.009) were significant predictors of death in the K pneumoniae group. CONCLUSIONS: A higher APACHE II score at admission and a higher frequency of coexisting malignancy may have contributed to the higher, although not significant, mortality rate in patients with liver abscess caused by E coli infection. Clinicians should begin with broad antibiotic coverage such as a second-generation cephalosporin and an aminoglycoside with metronidazole when treating liver abscesses with E coli as the likely pathogen due to the high frequency of multi-drug-resistant isolates among E coli isolates.     

医院感染肺炎克雷伯菌的临床分布及耐药性调查

[摘要]目的：探讨医院感染肺炎克雷伯菌（KPN）的临床分布及耐药性，为I躏床医师合理用药提供实验室依据。方法：对187株肺炎克雷伯菌的标本来源和l临床科室分布进行调查，细菌培养与鉴定严格按照《全国临床检验操作规程》，采用常规方法进行；药敏试验采用K-B法，结果依据CLSI最新折点进行评价。结果：医院感染肺炎克雷伯菌对碳青霉烯类抗生素亚胺培南、美罗培南敏感率为100％，但对其他常用抗菌药物均产生了不同程度的耐药性，对氨苄西林耐药率最高，达到95．2％（178／187）。结论：各级医院应加大细菌耐药性监测力度，遏制细菌耐药性迅速增长的不良趋势。     

产超广谱β内酰胺酶菌株中质粒头孢菌素酶的研究

目的 调查产超广谱β内酰胺酶(ESBLs)的大肠埃希菌和肺炎克雷伯菌中质粒头孢菌素酶(AmpC酶)的发生率及其基因型。方法 收集北京朝阳医院2001年1～12月头孢西丁耐药的产ESBLs的24株大肠埃希菌、8株肺炎克雷伯菌,采用等电聚焦电泳测定β内酰胺酶的等电点;接合试验证实酶基因有无可转移性;脉冲场凝胶电泳(PFGE)确定耐药株的亲缘关系;对AmpC酶基因进行多重PCR及序列分析确定其基因型。结果 2001年北京朝阳医院ESBLs的发生率,大肠埃希菌为16.8％(49／292),肺炎克雷伯菌为160.5％(35／212);ESBLs株中质粒AmpC酶的发生率,大肠埃希菌为2．0％(1／49),肺炎克雷伯菌为17．1％(6／35)。这7株菌均产生DHA-1型AmpC酶;1株肺炎克雷伯菌可将头孢西丁耐药性传给受菌体。该7株菌都产TEM-1酶、5株产CTX-M-3型ESBL、2株产SHV-12型ESBL;该7株菌携带质粒2～5个,且都有约33～36kb的大质粒。PFGE发现这7株菌来自多个不同的克隆株。结论 北京朝阳医院ESBL阳性的大肠埃希菌和肺炎克雷伯菌中,有7株既产DHA-1型质粒AmpC酶,又产CTX-M-3或SHV-12 ESBL。这7株菌来自多个不同的克隆株。     

278株痰肺炎克雷伯菌耐药性分析

目的分析痰肺炎克雷伯菌的耐药性。方法使用VITEK-32全自动微生物分析系统进行细菌的鉴定、药物敏感性试验及ESBLs检测。结果278株痰肺炎克雷伯菌对AMP的耐药率98．56％。对IMI耐药率为0,对TZP耐药率为9．7％,AMK为12．23％,对AMPS、CIP、CTR、FD、FEP、GM、TOB耐药率均在30％以下,对CZ、SXT、ROX、ROXA、LEV耐药率均在30％～40％之间。产ESBLs株占19．06％,产ESBLs株对多种抗生素的耐药率高于不产ESBLs株,差异有统计学意义。结论痰肺炎克雷伯菌多种抗生素耐药,对IMI均敏感,对AMP耐药率最高,产ESBLs株耐药率高于不产ESBLs株。     

Defining principles that influence antimicrobial peptide activity against capsulated Klebsiella pneumoniae

The extracellular polysaccharide capsule of Klebsiella pneumoniae resists penetration by antimicrobials and protects the bacteria from the innate immune system. Host antimicrobial peptides are inactivated by the capsule as it impedes their penetration to the bacterial membrane. While the capsule sequesters most peptides, a few antimicrobial peptides have been identified that retain activity against encapsulated K. pneumoniae, suggesting that this bacterial defense can be overcome. However, it is unclear what factors allow peptides to avoid capsule inhibition. To address this, we created a peptide analog with strong antimicrobial activity toward several K. pneumoniae strains from a previously inactive peptide. We characterized the effects of these two peptides on K. pneumoniae, along with their physical interactions with K. pneumoniae capsule. Both peptides disrupted bacterial cell membranes, but only the active peptide displayed this activity against capsulated K. pneumoniae. Unexpectedly, the active peptide showed no decrease in capsule binding, but did lose secondary structure in a capsule-dependent fashion compared with the inactive parent peptide. We found that these characteristics are associated with capsule-peptide aggregation, leading to disruption of the K. pneumoniae capsule. Our findings reveal a potential mechanism for disrupting the protective barrier that K. pneumoniae uses to avoid the immune system and last-resort antibiotics.

Multidrug-resistant (MDR) bacterial infections have become a major threat to human health (1–3). Mortality rates from infections caused by gram-negative bacteria, specifically Klebsiella pneumoniae, are on the rise owing to the lack of effective antibiotics to treat the emergent MDR strains (4–7). The capsule of K. pneumoniae is composed of extracellular polysaccharides that promote infection by masking the bacteria from immune recognition and provide an especially potent barrier against peptide-based antimicrobials, including innate host defense peptides and last-resort polymyxin antibiotics (8–14).Antimicrobial peptides are commonly amphipathic, with both a charged and a hydrophobic character (15). The anionic nature of the bacterial capsule promotes an electrostatic attraction to cationic antimicrobial peptides, and peptide hydrophobicity has been proposed to enhance capsule binding through nonionic interactions (9, 12, 16). Interaction with the bacterial capsule is thought to induce structural changes that cause sequestration of antimicrobial peptides to prevent them from reaching their bacterial membrane target (16, 17). While the bacterial capsule inhibits host defense peptides and polymyxins, a few amphipathic antimicrobial peptides have been identified that can retain activity against capsulated K. pneumoniae (18–21). However, it is not known what enables some peptides to avoid sequestration by the capsule of K. pneumoniae while the capsule effectively neutralizes our innate host defense peptides with similar physicochemical properties. This lack of knowledge prevents us from understanding how to bypass the capsule barrier that K. pneumoniae uses to avoid our innate immune response and last-resort treatment options.Here we characterize the synthetic evolution of a peptide inhibited by capsule to a peptide with potent activity against capsulated K. pneumoniae. Remarkably, our results indicate that rather than reduced interactions, our active peptide retains binding to capsule and undergoes conformational changes associated with capsule aggregation. We present a model in which peptide-driven sequestration of capsule disrupts this barrier and reduces its ability to protect K. pneumoniae against antimicrobial attack. These findings provide insight into improving antimicrobial peptide activity against K. pneumoniae and may help strengthen our understanding of the inability of innate host defense peptides to act on capsulated bacteria.     

Plasmid-mediated Extended-spectrum beta-Lactamases in Organisms Other Than Klebsiella pneumoniae and Escherichia coli: A Hidden Reservoir of Transferable Resistance Genes

Conclusions Resistance due to AmpC β-lactamases and ESBLs in gramnegative bacillary pathogens is a growing and important problem and is tied to extensive use of extended-spectrum cephalosporins The emergence of these β-lactamases is then amplified by spread of resistant clones or resistant genes among patients within institutions or among patients who move between institutions within a region. Genes encoding β-lactamases are frequently linked to resistance genes for other classes of antibiotics. Thus, use of any one class of antibiotic may select for emergence of resistance to another. Treatment of infections caused by these multidrug-resistant pathogens is often problematic. One strategy to circumvent β-lactamase production has been use of β-lactam/β-lactamase inhibitor combinations, but AmpC β-lactamases and hyperproduction of ESBLs evade this therapeutic strategy. Use of carbapenems and cefepime, which are the most stable of all β-lactam antibiotics to hydrolysis by ESBLs and AmpC β-lactamases, can be expected eventually to select for emergence of resistance to these drugs as well. Traditional isolation precautions that include use of gloves and gown have been shown to be effective during contact with the patient infected or colonized with ESBLproducing K. pneumoniae or E. coli. However, if infection control efforts are directed only at those isolates that the laboratory is capable of identifying as ESBL-producers, the presence in an institutional setting of undetected plasmidencoded ESBLs in Enterobacteriaceae, other than K. pneumoniae and E. coli, will likely be an epidemiologic hazard. A patient infected with these organisms is a hidden reservoir of plasmid-encoded resistance genes that can spread among different species of Enterobacteriaceae. Development of rapid assays to detect the presence of these resistance genes would be a major asset. Control measures that may be effective include early detection of ESBLs in any Enterobacteriaceae, especially Enterobacter species or P. aeruginosa; universal glove use and hand hygiene; cohorting of colonized or infected patients; implementation of control measures simultaneously in all health care facilities linked by patient transfers; and of greatest importance, control of unnecessary and inappropriate antibiotic use.     

Resistance to antimicrobial agents, hemolytic activity and plasmids in Aeromonas species

A total of 174 Aeromonas isolates consisting of 100 strains from patients with diarrhea being mainly overseas travellers nd healthy subjects, and 74 strains from environmental sources including foods, fish, fresh water, sea water and river soil collected in the area of Tokyo Metropolis and Kanagawa Prefecture was examined for the antimicrobial resistance, presence of plasmids and hemolytic activity. Almost all the isolates (99.4%) were resistant to aminobenzyl penicillin. The isolation frequency of chloramphenicol- or tetracycline-resistant strain was low. Most environmental isolates of A. hydrophila were resistant to multiple antimicrobial agents. Thirty-seven percent of environmental isolates and 39% of human fecal ones carried plasmids. In environmental isolates, seven A. hydrophila and three A. sobria strains carried 63- to 150-kilobase pair (kb) conjugative R plasmids. Two A. hydrophila strains from both the healthy subject and domestic case with diarrhea carried 58- to 90-kb conjugative R plasmids, respectively. None of the isolates from the feces of overseas traveller's diarrhea carried the plasmid. Irrespective of the sources. A. hydrophila showed the highest hemolytic activity among three Aeromonas species. Eighty percent or more of A. hydrophila isolates were of hemolysin positive. The hemolytic titer of A. hydrophila strains from human feces was higher than that of the strains from environmental sources.