Analysis of AmpC β-lactamase Gene in Pseudomonas aeruginosa

The gene and the amino acid sequence of the structural and regulatory region of the Pseudomonas aeruginosa with different resistance patterns were analyzed. Six strains with different resistance patterns were selected and the AmpC β-lactamase was identified. The objective gene fragment was amplified by colonies PCR. The sequences of the PCR-products were analyzed. The DNA sequence of the structural gene ampC and the regulatory genes ampR, ampD and ampE was detected. The 6 strains and the wild-type Pseudomonas aeruginosa are highly homogeneous in structural and regulatory region. Some new mutant points were found.

Phenotypic and Genotypic Characterization of Extended Spectrum Beta-Lactamases Producing Bacteria Causing Urinary Tract Infections among Expectant Women Attending Antenatal Clinic at Ruiru Sub County Hospital, Kenya

Background: Urinary tract infection (UTI) is a bacterial infection affecting males and females but is more prevalent in expectant women. ESBLs are bacteria with enzymes that make them resistant to many antibiotics, posing a significant health challenge. This study aims to determine the characteristics of ESBL-producing bacteria causing UTIs in expectant women. Methodology: A self-administered survey was carried out;300 expectant women were recruited using a random sampling method. A questionnaire was used to collect socio-demographic information. Urine samples were collected in sterile universal bottles and processed at the JKUAT Zoology laboratory. Urine samples were analyzed using urinalysis, microscopy, culture, and sensitivity testing. ESBL-producing bacteria were identified phenotypically using the double-disc synergy test (DDST) and genotyped for specific resistant genes using PCR. Results: UTI prevalence was 32.7% (98/300). UTI was significantly associated with the history of previous UTI (OR = 0.84, p = 0.02) and multigravida (OR = 0.14 p = 0.01). UTI was common in women aged between 28-37 years in their second trimester. Bacteria isolated were E. coli 57.1% (56/98), S. aureus 21.4% (21/98) K. pneumonia 11.2% (11/98) and Proteus spp 10.4% (10/98). Bacteria antibiotic resistance patterns were E. coli-tetracycline (91.1%), sulfamethoxazole (55.4%), cefotaxime (53.4%) and augmentin (53.4%). S. aureus-sulfamethozaxole (100%) and augmentin (71.4%), K. pneumoniae-sulfame-thoxazole (72.2%) cefotaxime (63.6%), chloramphenicol and tetracycline (54.5%). Proteus spp: tetracycline (100%), nitrofurantoin (90%), cefotaxime and chloramphenicol (50%). The proportion of ESBLs bacterial producers was 37.6% (29/77) and 44.8% (13/29) possessed ESBLs resistant genes;Bla CTX-M 53.8% (7/13), Bla SHV and Bla TEM 23.1% (3/13) each, Bla OXA (0%) was not detected. Conclusion: The study revealed a high proportion of ESBLs producing bacteria responsible for UTI in expectant women. ESBLs screening, routine culture and sensitivity testing will guide on proper management and empirical treatment of UTI patients thus reducing multi-drug resistance.

Antimicrobial Susceptibility and Genotyping of Plasmid Mediated- Extended Spectrum β-lactamase, AmpC β-lactamase and Aminoglycoside Modifying Enzymes in Klebsiella pneumoniae

The antimicrobial susceptibility and genotyping of plasmid mediated-extended spectrum β-lactamase (ESBLs), AmpC β-lactamase (pAmpC) and aminoglycoside modifying enzymes (AMES) in Klebsiella pneumoniae isolated in Tianjin, China were investigated in the present study. Sixty strains of Klebsiella pneumoniae isolated from Huanhu Hospital were tested against 21 antimicrobial agents by Microscan MIC method, and the PCR and DNA sequencing were used to determine the genotypes of ESBLs, pAmpC and AMES. The result in antimicrobial susceptibility testing showed that all the 60 strains of bacteria tested were proved to be multi-resistant, and that of genotyping demonstrated different genotypes among these bacterial strains, in which 60 strains belonged to the TEM type; 25 strains to the CTX-M type and 54 strains to the DNA pAmpC type. The AMES genes were found in 59 strains, while the CTX-M type of ESBLs, DHA pAmpC type AMES genes were detected in 22 strains simultaneously. It concludes that the problem of drug-resistance of Klebsiella pneumoniae on hospital in Tianjin is a serious issue, and at least 3 kinds of β-lactamase and 3 AMES genes exist.

Molecular Detection of Extended-Spectrum Beta Lactamase and Carbapenemase Genes in Escherichia coli and Salmonella spp. Isolated from Chickens Consumed Outdoors in Ouagadougou, Burkina Faso

This study was carried out to assess the prevalence of resistance genes in strains of Escherichia coli and Salmonella spp. isolated from free-range chickens in Ouagadougou, where resistant bacteria can be transmitted to humans via faeces or contaminated meat. A total of 280 strains of Escherichia coli and 129 strains of Salmonella spp. resistant to at least one beta-lactam or carbapenem antibiotic were used in this study. PCR analyses revealed the presence of ESBL (extended spectrum beta lactamase) resistance genes in Escherichia coli isolates, with 3.21% (9/280) possessing the CTX-M (Cefotaximase) gene, 15.35% (43/280) had the SHV (Sulfhydril Variable) gene, and 11.42% (32/280) had carbapenemase resistance genes, more specifically IMP (Imipenemase metallo-beta-lactamase). As regards Salmonella spp. strains, only the presence of the SHV (Sulfhydril Variable) gene was identified in 2.32% (3/129) of isolates belonging to the ESBL family, while 26.35% (34/129) and 13.95% (18/129) of isolates respectively possessed the IMP (Imipenemase metallo-beta-lactamase) and NDM (New Delhi metallo-β-lactamase) genes, both of the carbapenemase type. The significant prevalence of resistance genes in bacterial strains isolated from chickens sold outdoors in Ouagadougou raises major public health concerns, due to the possible transmission of these resistant strains to humans through the consumption of contaminated meat, thus complicating the treatment of bacterial infections.

Phenotypic Characterization of Extended Spectrum Beta-Lactamase, Class C Cephalosporinase and Carbapenemase-Producing Klebsiella Species Isolated from Patients Consulted at Four Yaounde-Based Hospitals

Background: Klebsiella spp. are bacteria of medical importance for their role in opportunistic infections which are often difficult to treat because of resistance to one or several antimicrobials. The aim of this study was to determine antimicrobial resistance due to Extended Spectrum Beta-lactamase (ESBL), Class C cephalosporinase (AmpC) and carbapenemase enzymes in Klebsiella spp. isolated from patients consulted at four hospitals. Methodology: The study was cross-sectional and descriptive. A total of 4190 non-repetitive patients specimens from 13 types of clinical specimens were analysed from February to November 2020. Two hundred and twenty-five (225) Klebsiella spp isolates were identified using API 20E and antimicrobial susceptibility testing done according to the Kirby Bauer disc diffusion method. ESBL and AmpC phenotypes were determined by the combination disc method and carbapenemases by double disc synergy method, referenced by EUCAST guidelines for the resistance testing. Results: The frequency of the species was Klebsiella pneumoniae (69%, 155/255), K. oxytoca (14%, 31/255), K. ozaenae (12%, 27/225) and K. rhinoscleromatis (5%, 11/225). Isolates were most resistant to sulphomethoxazole trimethoprim (84%, 189/225), cepaholosporins (80%, 180/225), and least resistant to carbapenems (10.7%, 24/225). Two K. oxytoca and one K. pneumoniae were resistant to all antibiotics tested. Klebsiella pneumoniae had the most multidrug resistant isolates (59.4%, 134/225). Most isolates (83.6%, 188/225) expressed at least one enzyme, while 63.6% (143/225) of the isolates expressed at least two enzymes. Some isolates were ESBL (71.6%, 161/225), carbapenemase (10.7%, 24/225) and AmpC (6.6%, 15/225) producers. Three carbapenemases (Klebsiella pneumoniae carbapenemase-KPC, Metallo-Beta Lactamase-MBL and OXA-48) were detected. Conclusion: These results revealed that resistance of Klebsiella spp. to cephalosporins is high and this may be exacerbated by co-expression of AmpC and carbapenemases aggravating associated patient morbidity and mortality. Monitoring of antimicrobial resistance of local strains is necessary for informed decisions on empirical treatment. .

Characterization of Extended Spectrum Beta-lactamase and Carbapenamase Producing Enterobacteriaceae Causing Urinary Tract Infection among Children in Kenya: A Cross-Sectional Study

Introduction: Enterobacteriaceae causing urinary tract infections (UTI) have developed resistance to the commonly used antibiotics due to emergence of Extended Spectrum Beta-Lactamases (ESBLs) and Carbapenamase producing Enterobactericeae which are a public health problem worldwide. This study aims to determine the prevalence and characterize ESBLs and carbapenamase producing Enterobactericeae. Method: A cross-sectional study was carried out in Gertrude’s Children’s Hospital, Nairobi. 238 urine samples were collected from patients with urinary symptoms attending the outpatient department within the period 2020-2021. The urine were examined macroscopically and microscopically. Identification and antimicrobial susceptibility testing were done using VITEK® 2 Compact system (BioMérieux). Double disc synergy test and modified hodge tests were done as confirmatory tests for ESBLs and Carbapenamase phenotypes respectively. Polymerase Chain Reaction was used for the detection of blaCTX-M, blaTEM, blaSHV, blaKPC and blaOXA-48 genes. Results: From the 238 children sampled the prevalence of UTI caused by Enterobactericeae was 22.3%. The Enterobacteriaceae species isolated were Escherichia coli (84.9%), Klebsiella pneumoniae (5.66%), Proteus mirabillis (5.66%), Enterobacter aerogenes (1.89%) and Morganella morganii (1.89%). The isolated species were resistant to ampicillin. Meropenem had the highest susceptibility. Only E. coli species had the ESBLs (26.4%) and carbapenamase (1.9%) phenotypes. 100% had BlaCTX-M while 50% had blaTEM resistant gene. There was a significant association (p Conclusion: Ampicillin resistance resulted to use of alternative drugs and Meropenem was the drug of choice where increased resistance to the recommended drugs was noted. Further research on resistant genes is recommended.

Microbiologic and Clinical Comparison of Patients Harboring <i>Escherichia coli</i>Blood Isolates with and without Extended-Spectrum <i>β</i>-Lactamases

The clinical and microbiologic characteristics of 34 patients with extended-spectrum β-lactamase (ESBL) positive E. coli isolated from blood were compared to 66 bacteremic patients with ESBL negative E. coli, from January 2007 through December 2009. Of the 21 ESBL positive isolates available for PCR analysis, 13 were positive for CTX-M, 8 for TEM, 4 for SHV β-lactamases, with 6 possessing multiple enzymes. Twenty of 34 (59%) ESBL-positive and 41 of 66 (62%) ESBL-negative blood isolates were considered community-associated. All but one isolate in both groups had MICs of ≤1.0 μg/ml to meropenem. However, when compared to ESBL-negative isolates, ESBL-positive isolates were more frequently resistant to levofloxacin, trimethoprim/sulfamethoxazole and had higher MICs to gentamicin, tobramycin and piperacillin/tazobactam. The use of intravenous and urinary catheters was strongly associated with the isolation of E. coli bloodstream isolates in both groups of patients. Although hospital stay was similar in both groups, appropriate therapy was given in 87% of patients with ESBL positive vs. 98% of patients with ESBL negative isolates and mortality was greater for patients with ESBL positive isolates (26% vs. 17%). Since a large proportion of E. coli blood isolates were ESBL-positive and community-associated, carbapenems should be considered as initial empiric therapy for such infections in our locale.

Activity of Fosfomycin in Extended-Spectrum Beta-Lactamases Producing Klebsiella pneumonae from Hospital Acquired Urinary Tract Infections

Treatment of hospital acquired urinary tract infections (UTIs) caused by extended-spectrum beta-Lactamases producing Klebsiella pneumonae is a major problem. This organism expresses a high level of resistance to many groups of antibiotics. Fosfomycin is an agent which is recommended for treatment of UTIs caused by ESBLs producers. The aim of this study is to determine the sensitivity pattern of ESBLs producing urinary K. pneumonae to antimicrobial agents including fosfomycin in patients of MUHs and determine the prevalence of fosfomycin resistance mediated by plasmid mediated fosfomycin modifying enzymes fosA, fosB and fosA3. Methods: Klebsiella pneumonae urinary isolates were collected from patients with hospital acquired UTIs in Mansoura University Hospitals (MUHs). The susceptibility pattern was determined by Kirby Baur method. Isolates resistant to extended spectrum cephalosporins were tested for ESBLs production by double disc diffusion method. Fosfomycin resistance was determined by broth dilution method. Isolates resistant to fosfomycin were tested for fosA, fosB and fosA3 by PCR. Results: A total of 128 ESBLs producing K. pneumonae isolates were collected. The highest sensitivity was to imipenem (94.5%). The lowest was to trimethoprime-sulphamethoxazole (21.8%). Co-resistance of ESBLs isolates with fosfomycin was 23.2%. Eighteen fosfomycin resistant isolates (18/30) were positive to fosA. Conclusion: ESBLs producing urinary Klebsiella pneumonae express moderate sensitivity to fosfomycin. Resistance is mainly mediated by plasmid mediated fosfomycin modifying enzymes fosA.

Characteristics of β-Lactamase Synthesis in E. coli and K. pneumanie Strains in Nosocomial Infections

Background: Recently micro-organisms that synthesize extended-spectrum β-lactamase (ESBLs) were increased. The peculiarities of ESBL synthesis of Escherichia coli and Klebsiella pneumoniae strains that cause nosocomial urinary tract infections, surgical site infections and pneumonia in surgical clinic were studied. ESBL synthesis were observed 38.9% of E. coli strains obtained from urine, 92.3% of strains obtained from surgical site infections, and 50% of strains obtained from sputum. ESBL synthesis were observed 37.5% of K. pneumoniae strains obtained from urine, 85.7% of strains obtained from surgical site infections, and 60% of strains obtained from sputum. Different levels of ESBL synthesize of E. coli and K. pneumoniae strains isolated from different pattern is discussed. Conclusion. ESBL synthesis is common in E. coli and K. pneumoniae strains, which cause nosocomial infections. The frequency of occurrence of ESBL s synthesis among of these strains depends on clinical forms of nosocomial infections.

Evaluation of Disk Potentiation Test (DPT) and Double Disk Synergy Test (DDST) for The Detection of Metallo-β-Lactamases (MBLs) in Clinical Isolates of Bangladesh

Objective: Increasing the emergence of Metallo-β-lactamase (MBL) producing gram-negative bacteria and their dexterous horizontal transmission demands rapid and accurate detection. This study was conducted to determine a suitable method to promptly detect MBL-producing gram-negative bacteria. Methods: A total of 103 gram-negative bacteria were identified from various clinical samples at a tertiary care hospital in Dhaka city. MBL producers were detected by two phenotypic methods, the Disk Potentiation Test (DPT) and the Double Disk Synergy Test (DDST) based on β-lactam chelator combinations where EDTA/SMA has been used as an inhibitor and Imipenem, Ceftazidime as substrates. Results: 103 isolates which were identified as Escherichia coli spp, Klebsiella spp, Pseudomonas spp, Acinetobacter spp, Proteus spp, Providencia spp were found to be multidrug-resistant in antibiogram test. Isolates showed complete resistance (100%) to Imipenem, Meropenem, and Amoxiclav. The highest carbapenem-resistant etiological agents were Acinetobacter spp 40 (38.8%) followed by Pseudomonas spp 27 (26.2%), Klebsiella spp 26 (25.2%), Escherichia coli 8 (7.8%), Proteus spp 1 (1%) and Providencia spp 1 (1%). DPT method detected significantly (p = 0.000009) a higher number of MBL-producers (Imipenem with 0.5 M EDTA n = 61, 59.2% & Ceftazidime with 0.5 M EDTA n = 56, 54.4%) compared to the DDST method (Imipenem -0.5 M EDTA n = 43, 41.7%, Imipenem – SMA n = 38, 36.9% & Ceftazidime -0.5 M EDTA n = 15, 14.6%). Conclusion: Pieces of evidence suggest that DPT is a more sensitive method than DDST and could be recommended for identifying MBL-producing bacteria in Bangladeshi hospitals for the proper management of patients, to reduce time constraints and treatment costs.

13种抗生素对产AmpC酶或同时产ESBLs细菌的体外抗菌活性

目的 了解临床下呼吸道感染常见革兰氏阴性杆菌产 Amp C酶或同时产超广谱β-内酰胺酶(ESBL s)的情况 ,检测常用 13种抗生素对这些菌株的体外抗菌活性 ,以指导临床合理选择抗生素。方法 采用酶提取物三维试验确证产 Amp C酶或同时产 ESBL s菌株 ,应用琼脂二倍稀释法测定抗生素对这些菌株的最低抑菌浓度 (MICs)。结果 从临床痰标本分离对第一、二代及一种以上第三代头孢菌素耐药的 2 2 6株常见革兰氏阴性杆菌 ,包括阴沟肠杆菌、弗氏柠檬酸杆菌、肺炎克雷伯氏菌、大肠埃希氏菌、鲍氏不动杆菌和铜绿假单胞菌 ,其中单产 Amp C酶 34株 ,同时产 Amp C酶和 ESBL s15株 ,总检出率分别为 15 .0 % (34/ 2 2 6 )、6 .6 %(15 / 2 2 6 )。无论单产 Amp C酶还是同时产 Amp C酶和 ESBL s的细菌对第三代头孢菌素、氨曲南及头孢美唑高度耐药 ,敏感率从 0～ 14 .7% ;对含 β-内酰胺酶抑制剂的复合制剂哌拉西林 /三唑巴坦、阿莫西林 /克拉维酸、头孢哌酮 /舒巴坦耐药情况亦严重 ,敏感率从 0～ 2 9.4 % ;对环丙沙星、左氧氟沙星除大肠埃希氏菌外有较高的敏感性 ,总敏感率均为 71.4 % ;而对亚胺培南高度敏感 ,仅有 1株铜绿假单胞菌耐药。单产 Amp C酶细菌对头孢吡肟、阿米卡星敏感率分别为 97.1%、6 4 .7% ,同时产 Amp C酶?

阴沟肠杆菌质粒型AmpC酶基因的研究

目的调查阴沟肠杆菌质粒型AmpC酶基因的流行状况及基因型。方法采用ATB药敏试验板微量肉汤法,对44株临床分离的阴沟肠杆菌进行抗菌药物敏感试验,PCR方法检测DHA和ACT型AmpC酶基因。结果44株阴沟肠杆菌呈多重耐药;36株质粒AmpC酶基因阳性(81.8%),DHA和ACT-1基因阳性率分别为11.4%、79.5%,而且3株阴沟肠杆菌同时携带DHA和ACT-1基因。结论临床分离的阴沟肠杆菌多重耐药严重、质粒AmpC酶基因携带率高;阴沟肠杆菌中检出ACT-1基因为国内首次报道。

肺炎克雷伯菌超广谱β-内酰胺酶和AmpC酶基因检测及耐药性分析

目的了解下呼吸道感染肺炎克雷伯菌超广谱β-内酰胺酶(ESBLs)和质粒AmpC酶的产生情况及耐药性,研究AmpC酶的基因型别。方法用纸片扩散确证法检测ESBLs;用酶提取三维试验检测AmpC酶,聚合酶链反应(PCR)扩增AmpC酶的基因,DNA序列测定检测AmpC酶的基因型;K-B法检测细菌耐药性。结果58株下呼吸道感染肺炎克雷伯菌中ESBLs阳性21株,AmpC酶阳性5株,其中3株ESBLs和AmpC酶均阳性,5株AmpC酶阳性菌中,4株扩增出DHA基因,经测序均为DHA-1,1株扩增出MIR基因。产酶菌株的耐药性明显高于非产酶株。结论肺炎克雷伯菌中ESBLs和AmpC酶均有较高的检出率,AmpC酶以DHA基因型为主。产ESBLs和AmpC酶是肺炎克雷伯菌耐药的主要原因。

肺炎克雷伯菌和产酸克雷伯菌中ESBLs和AmpC酶基因的研究

目的研究肺炎克雷伯菌、产酸克雷伯菌中ESBLs和AmpCβ-内酰胺酶的存在形式及其基因类型和转移方式。方法利用CLSI纸片法确认实验和APB纸片增强试验分别检测ESBLs和AmpC酶,基因芯片技术和序列分析测定两种酶基因的类型,接合转移实验了解肺炎克雷伯菌和产酸克雷伯菌耐药基因转移方式。结果在对头孢西丁不敏感的72株肺炎克雷伯菌和20株产酸克雷伯菌中,以同时产生ESBLs和AmpC酶为主要形式,分别占54.2%和75.0%;单产ESBLs分别为22.2%和25.0%,肺炎克雷伯菌中单产AmpC酶占12.5%;肺炎克雷伯菌和产酸克雷伯菌中的AmpC酶基因绝大多数为DHA型(测得DHA-1型基因),ESBLs则以SHV型为主(测得SHV-12型),它们均能通过接合转移方式将其质粒携带的耐药性传递至受体菌。结论同时存在的ESBLs和AmpC酶是肺炎克雷伯菌和产酸克雷伯菌耐药的主要原因,耐药基因的转移可导致耐药性的传播扩散。

肺炎克雷伯菌和大肠埃希菌AmpCβ内酰胺酶的表型检测

目的比较研究临床实验室对AmpCβ内酰胺酶(AmpC酶)的表型检测方法,了解对头孢西丁不敏感的肺炎克雷伯菌和大肠埃希菌中产生AmpC酶和超广谱β内酰胺酶(ESBLs)的分布情况。方法利用加与不加3-氨基苯酚硼酸(APB)的头孢他啶、头孢噻肟和头孢西丁纸片进行APB纸片增强试验检测肺炎克雷伯菌和大肠埃希菌的AmpC酶,并与Tris-EDTA纸片试验检测AmpC酶的结果进行比较。用CLSI纸片确认实验检测肺炎克雷伯菌和大肠埃希菌产生的ESBLs。结果APB纸片增强试验与Tris-EDTA纸片法检测结果完全一致。对头孢西丁不敏感的62株肺炎克雷伯菌和74株大肠埃希菌中,分别检测到产AmpC酶41株(66.1%)和33株(45.0%)。AmpC酶和ESBLs同时存在的肺炎克雷伯菌占51.6%,单产AmpC酶和单产ESBLs的肺炎克雷伯菌分别为14.5%和21.0%;而大肠埃希菌则以单产ESBLs为主,占40.5%,单产AmpC酶及同时产生AmpC酶与ESBLs的分别占20.3%和24.3%。结论APB纸片增强试验和Tris-EDTA纸片试验操作简单,应用方便,成本低廉,均可用于临床实验室检测产AmpC酶的肺炎克雷伯菌和大肠埃希菌。

产生ESBLs和AmpC酶的肠杆菌科细菌检测及耐药性分析

目的了解我院产ESBLs和AmpC酶细菌的耐药性。方法对产ESBLs菌和产生AmpC酶菌进行表型的筛选和确证,测定21种药物的耐药性。结果 268株菌中检出ESBLs菌136株,检出率50.75%,AmpC酶菌116株,检出率43.28%。单产AmpC酶菌,单产ESBLs菌及产AmpC和ESBLs的菌对青霉素、第二、三代头孢菌素类药物的耐药率明显高于非产酶菌的耐药率,两者相比有显著性差异(P<0.05),多重耐药及泛耐药常见。结论 ESBLs与Amp酶已成为我院肠杆菌科细菌耐药的主要原因。碳青霉烯类、第四代头孢菌素、哌拉西林/三唑巴坦成为我院治疗院内感染的首选药。

广州地区肠杆菌属高产AmpC酶和超广谱β-内酰胺酶调查

目的了解广州地区临床分离的肠杆菌属高产AmpC酶及超广谱β-内酰胺酶(ESBLs)的情况。方法采用头孢西丁和头孢曲松+氯唑西林三维试验。结果612株菌中初筛出381株可疑菌株进行检测,其中高产AmpC酶有88株(14.4%),产超广谱β-内酰胺酶(ESBLs)261株(42.6%),高产AmpC酶合并产ESBLs28株(4.6%);药敏分析亚胺培南对肠杆菌属耐药率最低为1.1%,头孢吡肟对高产AmpC酶菌株敏感性较高。结论应常规检测高产AmpC酶和ESBLs,强调临床合理应用抗菌药物。

耐头孢西丁革兰阴性杆菌高产AmpC酶发生率及基因型与耐药性研究

目的了解耐头孢西丁革兰阴性杆菌高产AmpC酶发生率及基因型分布和耐药性。方法对155株无重复耐头孢西丁革兰阴性杆菌,用酶提取物三维试验检测AmpC酶;ATB药敏试验板和K-B法检测产酶株的药物敏感性;质粒转化试验定位耐药基因;PCR扩增AmpC酶与ESBLs基因及其序列测定确定其基因型。结果高产AmpC酶的发生率为23.2%;自2株肺炎克雷伯菌和5株大肠埃希菌中检出DHA-1、CMY-2和CMY-22型AmpC酶,5株大肠埃希菌还分别同时携带TEM-1型广谱酶和TEM-144、CTX-M-27和CTX-M-14型超广谱β-内酰胺酶;CMY-22型和TEM-144型β-内酰胺酶是国内外首次报道,获得美国GenBank登录号分别为DQ256079和DQ256080。结论加强耐头孢西丁革兰阴性杆菌高产AmpC酶的监测,治疗相关菌感染以亚胺培南和美罗培南为首选;福州发现DHA-1、CMY-2和CMY-22型AmpC酶。

铜绿假单胞菌AmpC酶基因、调控基因及氨基酸序列研究

目的 测定不同耐药谱铜绿假单胞菌AmpC酶ampC基因、调控基因及氨基酸序列。方法 筛选铜绿假单胞菌株 6株 ,获取AmpC酶及鉴定 ,菌落PCR扩增目的基因片段 ,鉴定产物 ,测序。结果 测出了铜绿假单胞菌AmpC酶部分ampC基因、调控基因ampR、ampD及部分ampE的核苷酸序列。结论 所观察耐药菌株的ampC基因和调控基因ampR、ampD及ampE与标准菌株染色体介导的AmpC酶基因及氨基酸序列具有同源性 ;发现一些新突变位点。

高产AmpC酶肺炎克雷伯菌的临床报道

的 对临床分离出的高产AmpC肺炎克雷伯菌分子生物学以及耐药特性进行研究。方法 对从临床分离的 1株头孢西丁高度耐药的肺炎克雷伯菌进行分析 ;用三维试验初步检测其高产AmpC ,然后用等电聚焦以及酶抑制试验等进行确认 ;用接合试验检验耐药基因的转移性 ,最后用E TEST法进行最小抑菌浓度 (MIC)测定。结果 该菌株三维试验为阳性 ,等电聚焦以及酶抑制试验表明 ,该菌株产一种等电点 (PI)为 7 8的能够被氯唑西林抑制而不能被克拉维酸抑制的 β 内酰胺酶 ;接合试验表明表达该 β 内酰胺酶的基因具有转移性 ,用E TEST法检测表明该菌株对环丙沙星、阿米卡星、青霉素类、酶抑制剂合剂及三代头孢菌素类均耐药 ,但它们对头孢吡肟、碳青酶烯类的亚胺培南和伊他培南均敏感。结论 我院临床分离肺炎克雷伯菌已经出现中高产AmpC菌株 ,其耐药性能够水平传播 ,并造成对多种三代头孢菌素及头孢西丁耐药 ,已经对临床的抗生素治疗带来重大威胁。