Occurrence of K1 and K2 serotypes and genotypic characteristics of extended spectrumβ-lactamases-producing Klebsiella pneumoniae isolated from selected hospitals in Malaysia

Objective:To determine the distribution,phenotypic and genetic background of extended spectrumβ-lactamases(ESBL)-producing Klebsiella(K.)pneumoniae clinical isolates associated with K1 and K2 serotypes in two selected hospitals in Malaysia.Methods:A total of 192 K.pneumoniae isolates were collected and subjected to antibiotic susceptibility,hypermucoviscosity test and multiplex PCR to detect the presence of K1-and K2-serotype associated genes.Multilocus sequence typing(MLST)was performed on ESBL-producing K.pneumoniae isolates presented with K1 and K2 serotypes,followed by phylogenetic analysis.Results:A total of 87 out of 192(45.3%)of the K.pneumoniae isolates collected were ESBL producers.However,only 8.3%(16/192)and 10.9%(21/192)of the total isolates were detected to carry K1-and K2-serotype associated genes,respectively.Statistical analysis showed that K1 and K2 capsular serotypes were not significantly associated with ESBL phenotype(P=0.196).However,they were significantly associated with hypervirulent,as demonstrated by the positive string test(P<0.001).MLST analysis revealed that ST23 as the predominant sequence type(ST)in the K1 serotype,while the ST in the K2 serotype is more diverse.Conclusions:Although the occurrence of ESBL-producing isolates among the hypervirulent strains was low,their coexistence warrants the need for continuous surveillance.MLST showed that these isolates were genetically heterogeneous.

Appendical Perforation by Infection with Extended-Spectrum Beta-Lactamase (ESBL)-Producing <i>Escherichia coli</i>: Case Report

We report the very rare case of a huge appendical abscess with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli (E. coli) as the pathogen. There have been several reports of appendical infections such as appendicitis and appendical abscess caused by ESBL-producing bacteria in adults. The treatment of ESBL-producing E. coli infection is specific, and ESBL-producing bacteria have recently been reported as pathogens associated appendicitis in children. To the best of our knowledge, this is the second report of perforated appendicitis with abscess due to ESBL-producing E. coli. We discuss the diagnostic modalities and treatments for appendical abscess with ESBL-producing E. coli. and propose that the patients with perforated appendicitis and abscess formation due to ESBL-producing E. coli should be administered the antibiotic MEPM within 2 weeks to treat the abscess more effec-tively without producing other multidrug-resistant bacteria.

Diagnostic Validity of Cica Beta Test 1 for the Detection of Extended Spectrum Beta-Lactamase (ESBL) Producing Gram Negative Bacteria by Comparing with Phenotypic Method

Background: Detection of extended spectrum beta lactamase producing bacteria is an important issue in the clinical settings. Objective: The purpose of the present study was to validate the Cica Beta Test 1 for detection of extended spectrum beta-lactamase (ESBL) producing bacteria. Method: This analytical type of cross-sectional study was carried out in the Department of Microbiology and Immunology at Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka from January 2006 to December 2006 for a period of one (01) year. All the patients presented with the clinical features of urinary tract infection and surgical as well as burn wound infection at any age with both sexes were selected as study population. All bacteria were isolated and identified by their colony morphology, staining characters, pigment production, motility and other relevant biochemical tests. Phenotypic confirmation of ESBLs producing isolates were done by inhibitor potentiated disc diffusion test according to CLSI recommendation. The Cica Beta Test 1 was performed according to the manufacturer’s instructions. Result: A total number of 288 Gram negative bacteria were isolated. Among these isolates Cica Beta test 1 was positive in 97 strains and phenotypic confirmatory test was positive in 89 strains. The test sensitivity of Cica Beta Test 1 was 100% (95% CI 95.9% to 100.0%). Specificity of the test was 96.0% (95% CI 92.2% to 98.2%). The positive predictive value (PPV) and negative predictive value (NPV) were 92.7% (95% CI 84.5% to 95.7%) and 100.0% (95% CI 98.0% to 100.0%) respectively. The accuracy of the test was 97.2% (95% CI 95.1% to 99.1%). Area under ROC curve = 0.980 (95% CI 0.964 to 0.996);p value 0.0001. Conclusion: In conclusion, Cica Beta Test 1 is very high sensitivity and specificity for the detection of ESBL from Gram negative bacteria.

Prevalence and characteristics of extended spectrum β-lactamase-producing Escherichia coli from bovine mastitis cases in China

The aim of the study was to investigate the prevalence and characterization of extended-spectrum β-lactamase （ESBL）- producing Escherichia coli isolated from bovine mastitis cases in China. ChromID ESBL agar was used to confirm ESBL-producing E. coli. PCR and DNA sequencing were employed to characterize the genotype of ESBL-producers. Antimicrobial susceptibility was measured by disc diffusion. Overall, 73 of 318 E. coli isolates （22.96％） were identified as ESBL-producers. Of these ESBL-producing E. coli, the prevalence of blaCTX-M and blaTEM-1 was 97.26 and 71.23％, respectively. The predominant CTX-M-type ESBL was CTX-M-15 （65.75％）, followed by CTX-M-14 （10.96％）, CTX-M-55 （9.59％）, CTX-M-64 （5.48％）, CTX-M-65 （4.11％） and CTX-M-3 （1.37％）. This study is the first report of CTX-M-64 and CTX-M-65 in E. coli isolated from bovine mastitis. Furthermore, 72 ESBL-producing E. coli isolates （98.63％） were found to be multidrug-resistance. This study noted high prevalence and rates of antimicrobial resistance of ESBL-producing E. coli isolates from bovine mastitis cases in China.

Phenotypic Detection and Susceptibility Pattern for the Detection of Extended Spectrum β-Lactamase-Producing <i>Klebsiella pneumonia </i>Isolates in Nairobi, Kenya

Klebsiella pneumoniae is an opportunistic pathogen that is an important cause of nosocomial infections. Detection of ESBL producers’ poses a special challenge for clinical microbiology laboratories, although ESBL producing pathogens are able to hydrolyze extended-spectrum penicillins, cephalosporins, and aztreonam, the minimum inhibitory concentrations (MIC) of some and perhaps even all of these agents may be within the susceptible range. The third generation cephalosporins have the reputation for being useful against a broad range of bacterial infections. However, resistance to these agents is something that must still be considered and creates obstacles for their clinical use. A total of 80 multi drug resistant clinical isolates of Klebsiella pneumoniae were obtained from a study on anaerobes associated with Pelvic Inflammatory disease (P.I.D), KEMRI S.S.C No.495. The isolates were identified by standard microbiological procedures. Antimicrobial susceptibility testing was carried out by Kirby-Bauer method. Upon identification, the antibiogram profiles of the isolates were determined and those resistant to third-generation cephalosporins were tested for production of ESBL. ESBL production among the multi drug resistant isolates was detected using the phenotypic confirmatory disc diffusion test (PCDDT) and double disk synergy test (DDST). While using standard double disk synergy test (DDST) as screening method for identifying potential ESBL producers, ceftriaxone was the most efficient antimicrobial in screening isolates as potential ESBL producers followed by cefotaxime.

Intestinal carriage of methicillin resistant Staphylococcus aureus and extended-spectrum β-Lactamase-producing Enterobacteriacae in hospitalized and nonhospitalized patients and their clinical implications

Objective:To determine the clinical implication of and intestinal carriage with methicillin resistant Staphylococcus aureus(MRSA) and extended spectrumβ-lactamase(ESBL)-producing Enterobacteriacae.Methods: A total of 180 stool specimens were screened for MRSA and ESBL-producing enterobacteria.Identification of ESBL- producing Enterobacteriacae was done by MicroScan Walk Away 96 system(Dade Behring Inc.,West Sacramento,CA 95691,USA ) and confirmation by double-disc synergy test.MRSA was identified by disc diffusion using 30μg cefoxitin disc and the MicroScan.Results:The rate of fecal MRSA carriage was 7.8% (14/180),35.7%(5 /14) were recovered from surgical wards.Three patients(21,4%) had MRSA recovered from other body sites,and 2(14.2%) had in addition ESBL -producing Escherichia coli(E.coli) and Klebsiella pneumoniae(K.pneumoniae) respectively.Four(28.5%) patients with MRSA fical carriage died. MRSA fecal carriage was recovered from both inpatients and outpatients.Four(2.2%) cases carried ESBL-producing Enterobacteriacae in feces.Three(75%) were from intensive care unit(ICU).One patient had both ESBL-producing E.coli and K.pneumoniae from stool as well as E.coli from tracheal aspirate.Two ICU patients with fecal ESBL died.Conclusion:Fecal screening for MRSA and ESBL of all patients at high risk admitted to different hospital wards and ICUs and implementing infection control measures were recommended.

Multidrug resistance extended spectrum β-lactamase and AmpC producing Escherichia coli isolated from the environment of Bogor Slaughterhouse,Indonesia

To determine the multidrug resistance extended spectrum β-lactamase and AmpC (ESBL/AmpC producing) Escherichia coli (E. coli) isolated from the environment of Bogor slaughterhouse, Indonesia.MethodsA total of 35 samples from 7 locations in slaughterhouse i.e., source of water, slaughtering floor, swab of carcass area floor, swab of evisceration area floor, untreated waste water, treated waste water, drinking water for cattle were collected from March to April 2016. Presence of ESBL/AmpC producing E. coli and susceptibility testing against 8 antimicrobial agents (penicillin G, streptomycin, gentamycin, ciprofloxacin, enrofloxacin, tetracycline, trimethoprim-sulfamethoxazole, and polymyxin B) were detected by disk diffusion test according to Clinical and Laboratory Standards Institute.ResultsESBL/AmpC producing E. coli were identified in 14.3% (5/35) of the collected samples from the environment of Bogor slaughterhouse. ESBL/AmpC-producing E. coli isolates were detected in untreated waste water (n = 3), slaughtering floor (n = 1), and carcass area floor (n = 1). Most of ESBL/AmpC-producing E. coli isolates (80%) showed multidrug resistance phenotypes against at least three classes of antibiotics. The highest incidence of antibiotics resistance was against penicillin G (100.0%) and streptomycin (100.0%), followed by gentamicin (60.0%), trimethoprim-sulfamethoxazole (60.0%), tetracycline (40.0%), ciprofloxacin (40.0%), enrofloxacin (20.0%), and polymyxin B (0.0%).ConclusionsThe transmission of antimicrobial resistant bacteria into the environment may be a potential risk for human health.

Prevalence and Potential Risk Factors of Hospital Acquired Extended-Spectrum Beta-Lactamase—Producing <i>Proteus</i>Species

Background: Multidrug resistance and production of extended spectrum β-lactamases (ESBLs) by a large group of bacterial agents in hospitals are to be a matter of scientific concern. Objective: This cross-sectional study was aimed to investigate the prevalence of ESBL producing Proteus species and risk factors associated with hospital acquired infection in addition to study the antibiotics susceptibility patterns of all bacterial isolates from inpatients of four Yemeni general hospitals. Methods: A total of 740 consecutive non-repeat culture isolates were obtained from admitted patients of Al-Kuwait University Hospital, Al-Thowra General Hospital, Al-Jumhori Teaching Hospital, and Military General Hospitals Sana’a city. We used Kirby-Bauer disk diffusion method to detect antimicrobial susceptibility and establish the presence of ESBLs-producing bacteria according to the Clinical and Laboratory Standards Institute guidelines. Results: Out of 740 isolate, 233 (31.5%) were Escherichia coli followed by Staphylococcus aureus 188 (25.4%), Pseudomonas aeruginosa 149 (20.1%), Klebsiella sp. 107 (14.5%), Enterococcus faecalis 25 (3.4%) and Proteus spp. 38 (5.1%). The highest frequencies of ESBLs producing among Proteus sp. were Proteus mirabilis 26 out 38 (68.4%) and Proteus vulgaris 12 out 38 (31.6%). The most effective of antimicrobial susceptibility pattern among Proteus spp. were Imipenem (100%) followed by Pipracillin-Tazobactam (92.3%) for P. mirabilis and (83.3%) for P. vulgaris, while the Amikacin (80.8%) for P. mirabilis and P. vulgaris with (91.7%). Amoxicillin and Cefotaxime were the highest for both species (100%). Conclusion: The prevalence of ESBL-producing Proteus spp. detected in this study is of great concern for public health authorities and a strict adherence of infection control policies and procedures with continuous antibiotics resistance surveillance including antimicrobial management and routine detection of ESBL-producing isolates are very important to prevent nosocomial infections.

Unravelling Antimicrobial Resistance Phenotypes and Carriage of Extended-Spectrum β-Lactamase Genes in Escherichia coli Isolated from Dairy Farms in Kiambu County, Kenya

The use of antibiotics for prophylaxis and growth enhancement in livestock farming is on the increase globally. This practice has led to the emergence and spread of antimicrobial-resistant bacteria in livestock. Only limited research has been done to establish the role of cattle farming in antimicrobial resistance. The current study sought to establish the carriage of multi-drug resistance and extended-spectrum beta-lactamase genes in Escherichia coli from farmers, their cattle, and cattle slurry within Kiambu County. A total of 286 (81%) E. coli isolates were recovered from 352 samples analysed. Antibiotic resistance profiles showed 114 (40%) isolates were resistant to ≥3 antimicrobial classes and were considered multidrug-resistant. Among multidrug-resistant (MDR) E. coli strains, 40 (14%) were resistant to 3 different antimicrobial classes, while 71 (25%) were resistant to between 4 and 7 antibiotic classes. Extended-spectrum β-lactamase resistance was found in 18 isolates: human (n = 14), cattle (n = 2), and environmental (n = 2). Both the blaCTX-M and blaTEM genes were detected in 10 and 15 strains, respectively. Sequence analysis showed that the isolates carried the blaTEM-116 (n = 7), blaTEM-1 (n = 5), and blaCTX-M-15 (n = 8) genes. Genotyping MDR isolates using (GTG) 5 PCR demonstrated that the isolates were not clonal. This data shows antimicrobial resistance profiles and different types of resistance genes in the E. coli population on dairy farms. As a result, more effective, targeted public health policies and measures need to be put in place to control and prevent the emergence and spread of resistant bacteria.

Antimicrobial resistance, genotypic characterization and pulsed-field gel electrophoresis typing of extended spectrum β-lactamases-producing clinical Escherichia coli strains in Macao, China

Background The rise of the production of CTX-M class extended spectrum β-lactamases （ESBLs） has been well documented in traveling countries but no data are found for Macao, an international travel city. The objectives of this study were to identify the antimicrobial resistance pattern, and determine the prevalence, genotype and clonal relationship of ESBLs in 209 clinical Escherichia coli strains from Macao, China. Methods Antimicrobial susceptibility test was performed to determine the resistance patterns of the isolates using the disk diffusion method with 17 antimicrobial agents. Phenotypic detection was screened and confirmed according to the Clinical and Laboratory Standards Institute. Genotypic characterization was detected by isoelectric focusing analysis, polymerase chain reaction and sequencing. The clonal relationship between the different ESBL isolates was studied by pulsed-field gel electrophoresis （PFGE）. Results Imipenem and meropenem exhibited 100% susceptible among 209 strains. Overall, 82.3%, 67.3%, 52.9%, 51.2% and 51.0% of the isolates displayed resistance to ampicillin, tetracylcline, ciprofloxacin, sulfamethoxazole trimethoprin and gentamycin. The prevalence rate of ESBLs was 30.1%. Antibiotic resistances were found to be significantly higher among the ESBL producing group compared to non-ESBL producing group. We detected CTX-M-14 to be the major genotypic characterization of ESBLs （76.2%）. Two strains showed indistinguishable patterns by PFGE. Conclusions The prevalence of antimicrobial resistance is alarming high in Macao. Antimicrobial resistance is significantly higher among the ESBL producing group. This study documented CTX-M-14 as the predominant ESBL type. Although indistinguishable pattern was found between two strains, it was too small to decide whether any of the investigated strains was epidemic. Our findings may be also pertinent for other geographic areas undergoing similar travel characteristics to understand the corresponding effects on bacterial populations.

临床产ESBLs细菌的耐药特征和基因分型的研究

目的了解产超广谱β-内酰胺酶(ESBLs)细菌的流行和耐药特点,初步对产ESBLs细菌进行基因分型,确立耐药基因的位点和种类.方法收集分离鉴定菌株,通过K-B法药敏实验初筛以确认产ESBLs菌株,并对ESBLs基因进行初步分型.结果分离到产ESBLs细菌88株,检出率为38.9%,其中肺炎克雷伯菌阳性率为43.1%、大肠埃希菌阳性率为33.3%;产ESBLs细菌对青霉素类、氨曲南及头孢菌素类耐药率约为90%～100%,加用酶抑制剂克拉维酸或他唑巴坦后耐药率降为18.7%～46.8%;PCR初步分型结果表明:大多数产ESBLs细菌携带TEM型和SHV型β-内酰胺酶基因,其中单独携带TEM型基因的占42%,单独携带SHV型基因的占12.5%,携带两种基因的占31.8%.结论产ESBLs细菌具有多重耐药的特点;产ESBLs的大肠埃希菌和肺炎克雷伯菌大都携带TEM和(或)SHV型β-内酰胺酶基因,其中绝大部分产TEM型β-内酰胺酶.

多重耐药性大肠埃希菌质粒谱与ESBLs基因型分析

目的分析临床耐药大肠埃希菌质粒谱与基因型间关系,确定超广谱β-内酰胺酶e(xtended spectrum bata lactarnase,ESBLs)基因在细菌质粒谱上的座位。方法分离鉴定菌株,通过KB-法药敏实验确认产ESBLs菌株。凝胶电泳检测菌体质粒,并应用PCR技术扩增ESBLs基因。结果分离到产ESBLs细菌128株,检出率为78.0%,针对12种抗生素,产ESBLs细菌的耐药率在29%～71%之间;128株大肠埃希菌含11类不同谱型的质粒群,其中较大质粒(23kb、9.4kb)出现频率高(71.1%、26.6%);PCR分型结果显示,单独携带TEM型ESBLs基因的菌株比例为24.2%,SH V型为19.5%,CTXM-型为53.1%,携带两种基因型以上的占18.8%。CTXM-型中三个亚型CTXM--24、CTXM--22型和CTXM--3型比例分别是32.0%、28.1%和17.2%。结论质粒谱中,某些分子量相同或相近的较大质粒能稳定存在于菌体内并能导致相应耐药性的产生和播散。定位这类质粒上ESBLs基因的差异导致了菌株耐药性的不同。

产ESBLs鲍曼不动杆菌的耐药特性、质粒谱及耐药基因型

目的了解并研究产超广谱β-内酰胺酶(ESBLs)鲍曼不动杆菌的流行、耐药特点及质粒图谱,对产ESBLs菌株进行基因分型。方法先后用nitrocefin纸棒、最低抑菌浓度(M IC)初筛法和纸片扩散确认法从临床分离的鲍曼不动杆菌中检测产ESBLs菌株,用凝胶电泳分析其质粒图谱,并用聚合酶链反应(PCR)对产ESBLs基因进行分型。结果93株鲍曼不动杆菌中,对β-内酰胺酶类抗菌药物耐药47株(79.66%),中度敏感12株(20.34%);产ESBLs菌株有16株,占17.20%。产ESBLs鲍曼不动杆菌对头孢曲松、头孢他啶、头孢唑肟、头孢吡肟、氨曲南、庆大霉素、妥布霉素、磺胺甲唑、环丙沙星和阿米卡星的耐药率均显著高于非产ESBLs菌株(P<0.05)。保留的15株产ESBLs菌具有4种质粒谱,主要为Ⅰ型和Ⅲ型;它们均携带1～2种TEM型或SH V型或PER型β-内酰胺酶基因,且80%携带OXA-23型碳青霉烯酶基因。结论产ESBLs鲍曼不动杆菌常为多重耐药菌,耐药率与产ESBLs密切相关;同一克隆株在同一病房有流行趋势;本院流行株均携带2～3种耐药基因型,主要为TEM型、PER型β-内酰胺酶基因和OXA-23型碳青霉烯酶基因。

210株肠杆菌科细菌产ESBLs检测及耐药性调查

目的调查分析三种肠杆菌科细菌产ESBLs情况及其对11种抗生素的耐药性与耐药特点.方法对四川大学华西医院2003年7月～2004年1月从临床分离的210株对第三代头孢菌素(头孢他啶、头孢噻肟、头孢曲松)任一种MIC值≥2μg/ml的肠杆菌科细菌(主要为大肠埃希菌、肺炎克雷伯菌和阴沟肠杆菌)采用琼脂二倍稀释法测定11种抗菌药物的最低抑菌浓度(MIC).结果三种肠杆菌科细菌对环丙沙星的耐药率(以中敏和耐药合并计算)均超过50%;有90%的分离株对亚胺培南敏感.在氨基糖苷类抗生素中,以阿米卡星和依替米星的抗菌活性最强,阴沟肠杆菌对阿米卡星和依替米星耐药率较高,分别为56.77%和65.38%.结论肠杆菌科细菌对临床常用抗菌药物的耐药率均较高,多重耐药现象普遍,仅亚胺培南对其抗菌活性最强.

临床产ESBLs细菌耐药特性及其基因分型的研究

目的 了解并研究产超广谱 β-内酰胺酶 (ESBL s)细菌流行及耐药特点 ,应用聚合酶链反应(PCR)对产 ESBL s细菌进行初步分型。方法 先后用 nitrocefin及纸片扩散初筛法、纸片扩散确认法从临床分离的肺炎克雷伯氏菌及大肠埃希氏菌中检测产 ESBL s菌株 ,用微量稀释法测定不同类抗生素对产 ESBL s菌株的 MIC值 ,并用聚合酶链反应对 ESBL s基因进行初步分型。结果 我院临床分离肺炎克雷伯氏菌产ESBL s率为 16 .7%、大肠埃希氏菌产 ESBL s率为 12 .4%。产 ESBL s细菌对青霉素类及第三代头孢菌素类耐药率约为 70 %～ 10 0 % ,加用酶抑制剂后它们的耐药率降为 2 %～ 6 0 %。它们对磺胺甲口恶唑 /甲氧苄氨嘧啶、环丙沙星及头孢吡肟的耐药率分别为 6 9.2 3%、5 6 .41%和 2 0 .5 1% ,但它们对阿米卡星的耐药率为 12 .82 %。而非典型 β-内酰胺类抗生素头孢西丁、头孢美唑及拉氧头孢对产 ESBL s菌株的敏感率分别为 94.88%、92 .32 %和 97.44 %。碳青霉烯类的亚胺培南和美罗培南表现了最高的敏感率未发现耐药菌株。 ESBL s对单独头孢哌酮的水解率为 43.93% ,而当结合了舒巴坦、克拉维酸及三唑巴坦时对头孢哌酮的水解率分别下降为2 0 .91%、18.13%及 15 .2 7%。产 ESBL s肺炎克雷伯氏菌中产 SHV型、TEM型、SHV和

产ESBL肺炎克雷伯菌医院感染分子流行病学研究

目的 明确产 ESBL 肺炎克雷伯菌医院感染发生率及其流行病学特征。方法 收集、鉴定分离菌株 ,进行药敏实验和 ESBL 检测 ;PCR扩增 bla TEM和 bla SHV基因 ;等电聚焦测定 β-内酰胺酶的等电点 ( p I)、染色体 DNA的PFGE分型以及进行病例资料分析。结果 共分离到 10 4株非重复肺炎克雷伯菌 ,产 ESBL 株占 13 .5 %。医院感染株 ESBL 阳性率 ( 2 8.3 % )明显高于院外感染株 ( 3 .6% ) ;ESBL 阳性菌对 CPD、CTX、CAZ、CTR、ATM、FOX、CIP和 GEN的中敏或耐药率分别为 92 .9%、92 .9%、3 5 .7%、92 .8%、78.6%、7.1%、2 8.6%和 4 2 .9% ,但对IMP10 0 %敏感 ;β-内酰胺酶等电聚焦分析及 bla TEM和 bla SHV基因检测结果 ,提示该院流行的 ESBL 主要为 SHV类 ;PFGE分析证实在干部 1病区、SICU和 RICU存在产 ESBL 菌株流行。结论 该医院存在产 ESBL 肺炎克雷伯菌医院感染流行 ;合理使用抗生素 ,加强消毒隔离措施 ,严格遵守无菌操作规程和屏障护理 ,是控制医院感染流行的重要措施。

产ESBLs肠杆菌科细菌中整合子参与多重耐药机制研究

目的 观察产超广谱 β-内酰胺酶 (ESBL s)菌株的多重耐药情况 ,并分析产 ESBL s菌株中整合子的存在 ,同时对整合子的特性进行了初步研究。方法 采用 VITEK GNS药敏板测定庆大霉素等 13种抗菌药物对 12 6株产 ESBL s的肠杆菌属细菌的最低抑菌浓度 (MIC)。PCR技术检测整合子基因 ,应用 PCR定位技术和 DNA测序研究整合子插入耐药基因的情况。结果产 ESBL s的菌株对第三代头孢菌素、氨基糖苷、喹诺酮、磺胺类代表药如头孢噻肟、庆大霉素、培氟沙星、磺胺甲口恶唑 /甲氧苄氨嘧啶 (SMZ/ TMP)的耐药率分别为76 .2 %、6 7.5 %、76 .2 %、6 3.5 % ,对碳青霉烯类的亚胺培南全部敏感。产 ESBL s菌株质粒上存在三种大小不同的整合子 (扩增片段 94 0、180 0、2 6 0 0 bp) ,含有二氢叶酸还原酶基因和 β-内酰胺酶基因和核苷转移酶基因。结论 产 ESBL s菌株和非产 ESBL s菌株相比呈多重耐药 ,产 ESBL s菌株存在不同类型的整合子结构 ,含有多种耐药基因。整合子可以在细菌种内和种间引起多重耐药的水平传播。

下呼吸道感染产ESBLs肺炎克雷伯菌基因型分析

目的了解引起下呼吸道感染产 ESBLs 肺炎克雷伯菌的耐药性及 ESBLs 和 AmpC 基因型,指导临床合理用药。方法收集产 ESBLs 肺炎克雷伯菌36株。用纸片扩散法进行药敏性试验,表型筛选法检测出同时产 AmpC 酶的菌株,PCR 法检测 ESBLs 和 AmpC 酶的基因型。结果产 ESBLs 肺炎克雷伯菌对亚胺培南和美罗培南全部敏感,对所测试的其他药物呈不同程度耐药。36株产 ESBLs 肺炎克雷伯菌中,20株扩增出 CTX-M-Ⅲ群基因,15株扩增出 TEM 基因,SHV 和 OXA 基因各1株,ACT-1(MIR-1)和 DHA-1(DHA-2)各4株,12株细菌同时携带2种以上的基因型。结论本院下呼吸道感染患者中分离的产 ESBLs 肺炎克雷伯菌主要携带 CTX-M 和 TEM 基因型,少数携带 ACT、DHA、SHV 和 OXA 基因型,可介导对β内酰胺类药物的耐药。本研究未对 TEM 和 SHV 基因型作进一步分析。

鸭大肠杆菌超广谱β-内酰胺酶检测(ESBLs)及药物敏感性测定

对国内7个省份临床分离的32株鸭大肠杆菌进行超广谱β-内酰胺酶(ESBLs)检测及药物敏感性研究。结果表明,32株分离的鸭大肠杆菌中产ESBLs菌株7株,阳性检出率为21.87%;产ESBLs菌株对常用头孢三代及半合成青霉素类药物的敏感率低于42.9%,耐药率则高于28.6%,对阿莫西林、氨苄西林、头孢噻呋的耐药率高达100%。产酶菌株和非产酶菌株对新型头孢四代产品头孢吡肟及碳青霉烯类药物亚胺培南、美罗培南的敏感率高于96%。加酶抑制剂的β-内酰胺类抗生素如阿莫西林/棒酸、氨苄西林/舒巴坦、头孢哌酮/舒巴坦等对产酶菌株和非产酶菌株的敏感率全部高于未加酶抑制剂的单方药物。产ESBLs菌株存在多重耐药现象,酶抑制剂能够部分解决此类耐药性问题。

铜绿假单胞菌ESBLs检测及其流行病学分析

目的 为了解本地铜绿假单胞菌的耐药性及其分布情况 ,为控制和预防其流行提供科学依据。 方法 采用双纸片琼脂扩散法 ,测定 2 0 0 0～ 2 0 0 3年从临床标本分离的铜绿假单胞菌的ESBLs检测及药敏结果 ,比较该菌在病房、标本间的检出率、ESBLs阳性率、耐药性差异及年间变化。 结果 铜绿假单胞菌在各年检出的革兰氏阴性病原菌中均居第二位或第三位 ,住院标本检出率为 15 9%是门诊标本检出率 6 1%的 2 6倍 ,以五官耳鼻喉科、放疗科、康复科、心血管内科、老干病房、呼吸内科、心胸外科的呼吸道、伤口创面分泌物检出率较高。ESBLs总阳性率为 3 6 3 % ,前三年逐年下降 ( 5 7 1%～ 6 7% ) ,2 0 0 3年又呈上升趋势 ( 71 4% ) ( χ2 =3 3 163 ,P <0 0 5 )。对临床常用的氯霉素、丁胺卡那霉素、环丙沙星等均产生了很高的耐药性 ,最高达 10 0 % ,且ESBLs阳性菌株的耐药率明显高于阴性菌 (P <0 0 5或 0 0 1) ;对复合抗生素优力欣也已产生了较高的耐药性 ,对碳青霉烯类抗生素———泰能 ,复合抗生素舒普深、特治星的耐药性目前较低。 结论 铜绿假单胞菌ESBLs阳性菌在医院广泛存在 ,对临床常用的抗生素有很高的抗药性 ;应加强重点科室物表、空气和ESBLs监测及常住病人痰标本的送检 。