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.

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.

Detection of Beta-Lactamase and Extended-Spectrum Beta-Lactamase of Pathogens Isolated from Pig and Chicken and Their Antibiotic Susceptibility Test

The antibacterial activity of beta-lactam antibiotics or their combinations with inhibitor sulbactum against non-lactamase- producing strains, lactamase-producing and ESBLs-producing isolates was evaluated with twofold dilution method after pathogens isolated from pigs and chickens were detected, respectively, for beta-lactamase and extended-spectrum beta- lactamases （ESBLs）, The results revealed that most of 43 clinically isolated strains could produce beta-lactamase and 3 strains of shigella isolated from chicken samples produced ESBLs. All of 30 lactamase-producing strains isolated and only one of 16 non-lactamase-producing strains were resistant to amoxicillin and ampicillin. MICs of ampicillin against lactamaseproducing isolates decreased 10-40 and 10-20 times respectively, when it was conbined with sulbactam at ration of 1：2 and 1：4. All clinical isolates were susceptible to third-generation cephalosporins. The MICs of third-generation cephalosporins against lactamase-producing isolates did not change when they were conbined with sulbactam. MICs of ceftiofur and ceftriaxone against ESBLs-producing isolates decreased 2-4 times when they were conbined with sulbactam.

Post-appendectomy pelvic abscess with extended-spectrum beta-lactamase producing Escherichia coli : A case report and review of literature

BACKGROUND Appendicitis, the inflammation of the appendix, is the most common abdominal surgical emergency requiring expedient surgical intervention. Extendedspectrum beta-lactamases(ESBLs) are bacterial enzymes that catalyse the degradation of the betalactam ring of penicillins and cephalosporins(but without carbapenemase activity), leading to resistance of these bacteria to beta-lactam antibiotics. Recent increases in incidence of ESBL-producing bacteria have caused alarm worldwide. Proportion estimates of ESBLEnterobacteriaceae hover around 46% in China, 42% in East Africa, 12% in Germany, and 8% in the United States.CASE SUMMARY The impact of ESBL-producing bacteria on appendiceal abscesses and consequent pelvic abscesses are yet to be examined in depth. A literature review using the search words "appendiceal abscesses" and "ESBL Escherichia coli(E. coli)" revealed very few cases involving ESBL E. coli in any capacity in the context of appendiceal abscesses. This report describes the clinical aspects of a patient with appendicitis whodeveloped a postoperative pelvic abscess infected with ESBL-producing E. coli. In this report, we discuss the risk factors for contracting ESBL E. coli infection in appendicitis and post-appendectomy pelvis abscesses. We also discuss our management approach for postappendectomy ESBL E. coli pelvic abscesses, including drainage, pathogen identification, and pathogen characterisation. When ESBL E. coli is confirmed, carbapenem antibiotics should be promptly administered, as was done efficaciously with this patient. Our report is the first one in a developed country involving ESBL E. coli related surgical complications in association with a routine laparoscopic appendectomy.CONCLUSION Our report is the first involving ESBL E. coli and appendiceal abscesses, and that too consequent to laparoscopic appendectomy.

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 of Extended Spectrum Beta-Lactamase-Producing Escherichia coli in Broiler Chickens in YaoundéCapital City of Cameroon

Background: Escherichia coli are ubiquitous bacteria colonising both humans and animals. Extended spectrum β-lactamase-producing E. coli has been selected as a suitable indicator for the monitoring and surveillance of antimicrobial resistance. Death due to resistant bacteria is continuously rising in Cameroon, but the contribution of the aviary sector is not well studied. Therefore, this study aimed to investigate the resistance profile of extended spectrum beta-lactamases-producing Escherichia coli strains, isolated from faeces of broiler chickens in Yaoundé, capital city of Cameroon. Methods: A cross-sectional descriptive study was carried out from February to June 2020. Escherichia coli were isolated from samples of broilers in poultry farms in Yaoundé and submitted to the extended spectrum β-lactamase screening. The logistic regression was used to assess the statistical association of a significance threshold p-value of 0.05. Results: Out of 385 faecal samples collected in broiler farms, 114 Escherichia coli isolates were obtained out of which 30 (26.32%) were Extended Spectrum Beta-Lactamases-producing Escherichia coli. These isolates revealed high resistance to all antibiotic families. Poor storage conditions for feeds and the proximity to latrines, the troughs on the ground, the lack of foot bath and uniforms, the inadequate treatment of faeces, the poor usage of preventive antibiotics and the lack of water treatment have been identified as risk factors to faecal carriage of ESBL-producing Escherichia coli. Conclusion: This work reveals the emergence of Extended Spectrum Beta-Lactamases-producing Escherichia coli in poultry farms in Yaoundé and the failure in the biosecurity system. As such, the awareness of poultry breeders on the respect of biosecurity measures may be an effective tool to tackle antimicrobial resistance, specifically in livestock industries using a One Health approach.

Phenotypic and Genotypic Characterization of Metallo-Beta-Lactamase and Extended-Spectrum Beta-Lactamase among Enterobacteria Isolated at National Public Health Laboratory of Brazzaville

The improper use of antimicrobials against infectious diseases has allowed microorganisms to develop defense mechanisms that give them insensitivity to these agents. All bacteria are concerned by this phenomenon. This work aimed to assess prevalence of beta-lactamase produced by enterobacterial isolates. Then, disc diffusion, double disc synergy test (DDST) and combined disc test (CDT) were respectively used for antimicrobial resistance, detection of Extended-Spectrum Beta-Lactamases (ESBL) and Metallo-Beta-Lactamases (MBL). bla genes were detected by PCR. A total of 132 enterobacterial strains were studied. Resistance to antibiotic families was observed with a greater frequency than 50%. Gentamicin was the least active beta-lactam antibiotic, with a resistance rate of 88%. 40.9% of strains show an ESBL phenotype and 16.6% were MBL. An overall prevalence of 74% (40/54) and respectively rates of 29.6%, 27.7% and 16.7% for blaSHV, blaCTX and blaTEM genes were observed. SHV, CTX, CTX/SHV/TEM, CTX/TEM, SHV/TEM and CTX/SHV were different ESBL genotypes observed. ESBL-producing enterobacteria isolation worried about the future of antimicrobial therapy in the Republic of Congo. This is a public health problem that requires careful monitoring and implementation of a policy of rational antibiotics use.

Detection of Extended Spectrum β-Lactamase Producing Klebsiella pneumoniae and Escherichia coli in Two Hospitals in the Federal Capital Territory, Abuja, Nigeria

In this study, the prevalence of Extended Spectrum Beta-lactamase (ESBL) producing Klebsiella pneumoniae and Escherichia coli isolates from the University of Abuja Teaching Hospital and the National Hospital was determined. A total of two hundred and fifteen (215) clinical isolates were examined, of which 60% were E. coli and 40% K. pneumoniae respectively. The isolates were collected from various samples namely: Stool, Urine, Pus, High Vagina Swab, Sputum and Wound swab. Out of these isolates, 54 of K. pneumoniae were screened to be ESBL negative and 32 as ESBL positive isolates, while 88 and 40 E. coli were also screened as ESBL negative and ESBL positive isolates respectively. These represent 37.9% of all K. pneumoniae isolates and 31.25% of E. coli isolates respectively. The prevalence of ESBL among the species was not however statistically different (p > 0.05). Multiple resistance in these isolates was common and there is the need for routine screening of ESBL in our hospitals to guide rational and effective use of antibiotics.

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.

Identification of Klebsiella pneumoniae strains harboring inactive extended-spectrum beta-lactamase antibiotic-resistance genes

Background The extended-spectrum beta-lactamase （ESBL）-producing Klebsiella pneumoniae has increasingly become a major contributor to nosocomial infections and can exhibit multiple antibiotic resistance.Previous studies have focused on the resistance genes in ESBL-producing strains,and the resistance-associated genetic environment of non-ESBL-producing strains has been ignored until now.Here,we investigated the occurrence and characteristics of non-ESBL-producing K.pneumoniae,which potentially carries unexpressed resistance genes.Methods K.pneumoniae strains were collected from five medical institutions in China from February 2010 to August 2013.The VITEK-2 ESBL detection system was used as a primary screen to identify the ESBL-producing phenotype,and the three primary types of ESBL-associated genes （CTX,SHV,and TEM） were detected by polymerase chain reaction （PCR） to confirm the strains presenting with a non-ESBL-producing phenotype.mRNA expression in the non-ESBL-producing strains was further screened by reverse-transcription PCR （RT-PCR） to validate their transcriptional efficiency.Results Out of 224 clinically isolated antibiotic-sensitive K.pneumoniae strains with a non-ESBL-producing phenotype,5 （2.2％） were identified to carry inactivated ESBL blaSHV genes with intact upstream promoter regions and resistance gene sequences.Interestingly,three of the five antibiotic-sensitive K.pneumoniae strains containing ESBL blaSHV genes still exhibited mRNA transcription of blasHv,while the other two exhibited no mRNA transcription.Conclusion These findings suggest that inactivated ESBL genes exist in non-ESBL-producing antibiotic-sensitive K.pneumoniae strains,which have the potential to transform the strain into an ESBL phenotype if an inappropriate application or overdose of antibiotics is implemented during clinical management.

Beta-Lactam Antibiotic Resistance among <i>Enterobacter</i>spp. Isolated from Infection in Animals

Nosocomial infections are frequent complications of hospitalization, caused by opportunistic pathogens that gain access to hosts undergoing invasive procedures, such as surgery, intubation, and placement of deep vein lines. Nosocomial infections in animal hospitals can infect other animals, as well as be transmitted to human personnel. Enterobacter is a genus of common gram-negative bacteria, which can be associated with antibiotic resistant hospital infections. Because of an outbreak in antibiotic resistance in the genus, we decided to investigate five years of Enterobacter infections in the Large Animal Services of the Lois Bates Acheson Veterinary Teaching Hospital (LBAVTH) at Oregon State University. The demographics from 37 Enterobacter-infected patients of the LBAVTH were obtained from charts and analyzed. The identified clusters of infections suggested possible patient-environment sources of infection. The environment of the hospital was sampled in an attempt to determine the source of infection. Although Enterobacter was not isolated, three of the collected samples contained bacteria with resistance to third-generation cephalosporins. Enterobacter isolates from six of the 37 patients were further analyzed for presence of specific ESBL resistance genes. All six of the isolates harbored multiple extended-spectrum beta-lactamase genes, i.e., CTX-M-15, TEM-80, SHV-2 and AmpC. In summary, Enterobacter infection in the veterinary hospital was caused by beta-lactam-resistant strains, carrying ESBL-resistant genes. Veterinary hospital personnel should be aware of the potential for transmission, to both humans and animals, of ESBL-gene-containing bacteria.

Antimicrobial Resistance and β-Lactamase Production among Hospital Dumpsite Isolates

Metallo-β-Lactamases (MBLs) and Extended Spectrum β-Lactamses (ESBLs) have emerged world-wide as a significant source of β-lactam resistance. The emergence of MBLs and ESBLs encoded on plasmids among Gram-negative pathogens in hospital dumpsites was investigated. Soils of different government and private hospitals were collected and processed following standard bacteriological techniques. Antimicrobial susceptibility testing was carried out by the disk-diffusion technique using Ceftazidime (30 μg), Cefuroxime (30 μg), Cefotaxime (30 μg), Cefixime (5 μg), Trimethprim-sulfamethoxazole (25 μg), Gentamycin (100 μg) Amoxicillin-Clavunalate (30 μg), Ciprofloxacin (5 μg), Ofloxacin (5 μg), Nitrofurantoin (300 μg) and Imipenem (10 μg). The role of plasmids in resistance was evaluated by subjecting isolates to curing using Sodium Dodecyl Sulfate (SDS). ESBLs production by Double-Disk Synergy Test (DDST) was carried out. Isolates resistant to Imipenem were subjected to a confirmatory test using Modified Hodge’s test and to MBLs production by DDST. Eighty-two Gram-negative isolates comprising of 32 (39.02%) Escherichia coli, 20 (24.39%) Serratia marcescens, 14 (17.07%) Klebsiella pneumonia, 10 (12.28%) Proteus mirabilis and 6 (7.32%) Enterobacter aerogenes were obtained. Susceptibility results revealed a 100% resistance of all isolates to Ceftazidime, Cefuroxime, Cefixime, Amoxycillin-clavulanate and Cefotaxime. A total of 66 (80.48%) isolates harboured plasmids out of which 26 (31.71%) isolates were ESBL producers. MBLs production was observed in 8 (25.00%) E. coli, 2 (2.41%) Klebsiella pneumonia and 2 (2.41%) Proteus mirabilis isolates. All MBLs producing isolates were ESBLs producers. The finding of highly resistant isolates producing ESBLs and MBLs in a hospital environment is quite disturbing and should be addressed urgently.

猪鸡致病菌β-内酰胺酶、超广谱β-内酰胺酶检测与药敏试验

对分离的猪鸡致病菌,分别进行了?-内酰胺酶、超广谱β-内酰胺酶(ESBLs)检测,并用试管二倍稀释法测定了β-内酰胺环类抗生素或β-内酰胺环类抗生素与抑制剂舒巴坦联用对非产酶菌、产?-内酰胺酶菌、产ESBLs菌的抗菌活性.结果表明,43株分离菌的大多数可产生?-内酰胺酶,3株鸡志贺氏菌为ESBLs阳性菌株.30株分离产酶菌均对阿莫西林、氨苄西林耐药(MIC≥32 μg/ml),16株非产酶菌(标准菌株及分离株)中的15株对阿莫西林、氨苄西林敏感,只有一株非产酶分离菌耐药.氨苄西林与舒巴坦以2∶1、4∶1配比联用时,其对分离产酶菌的MIC值分别降低10~40倍、10~20倍.临床致病菌对三代头孢均敏感,与舒巴坦以2∶1、4∶1配比联用时,三代头孢的MIC值不变.当头孢噻呋、头孢曲松与舒巴坦以2∶1配比联用时,其对产ESBLs菌的MIC值降低2～4倍.

广州地区革兰阴性杆菌CTX-M和OXA型广谱β-内酰胺酶基因分型研究

目的调查广州地区临床分离的革兰阴性杆菌中CTX-M型超广谱β-内酰胺酶(ESBLs)和OXA型广谱β-内酰胺酶(beta-lactamase,Bla)的主要基因型别及其流行情况。方法按照NCCLS 2001年标准筛选广州地区临床分离菌株的ESBLs表型;用聚合酶链反应(PCR)扩增法和DNA测序法进行ESBLs基因序列分析。结果PCR扩增结果显示,CTX-M1、CTX-M2、CTX-M9群和OXA的总阳性率在本地区临床分离的临床检测ESBLs阳性的革兰阴性杆菌中分别为9.96%、0、35.5%和1.6%,同时检出≥两种ESBLs基因的菌株数64株,阳性率为5.9%;序列分析进一步证实了CTX-M型ESBLs的具体型别,包括CTX-M-3、CTX-M-22、CTX-M-9、CTX-M-14、CTX-M-17、CTX-M-18、CTX-M-21、CTX-M-24、TOHO-2和TOHO-3,其比例分别为3.23%、3.7%、4.99%、3.32%、2.21%、3.69%、2.95%、4.43%、1.85%和1.48%;其中以CTX-M-9和CTX-M-24阳性率较高;在本地区只检出1种OXA型Bla-OXA-2/PSE-2(1.38%,15/1084);另外,还检出了8株无法具体归类的CTX-M-9型ESBLs,占0.74%;CTX-M型基因主要分布于大肠埃希菌和肺炎克雷伯菌中,分别占42.8%和36.3%,而OXA基因则主要分布于铜绿假单胞菌中,占80%。结论本地区CTX-M类ESBLs也较为常见,其中尤以CTX-M-9和CTX-M-24为主,暂无CTX-M2群ESBLs,可能存在1种或多种新的CTX-M型ESBLs。

肺炎克雷伯菌超广谱β-内酰胺酶基因型研究

目的探讨我院肺炎克雷伯菌中超广谱β-内酰胺酶(ESBL s)基因分布规律。方法对20株经双纸片试验确证为ESBL s表型阳性的肺炎克雷伯菌进行blaTEM-1、blaSHV-1、CTX-M-1组、TOHO-1组等4种基因PCR扩增,并对16株blaSHV-1基因PCR扩增阳性的菌株进行基因序列测定,在In ternet网上与G enB ank中的已知序列进行核苷酸相似性分析,并进行编码基因对位和氨基酸序列对比分析。结果产ESBL s肺炎克雷伯菌中blaTEM-1、blaSHV-1、CTX-M-1组等3种基因扩增阳性率分别是50.0%、95.0%、20.0%。16株肺炎克雷伯菌中有4株序列与SHV-1a(序列号:X 98101,74→934)氨基酸序列完全相同;有3株序列与SHV-2(序列号:AY 570959,42→812)100%相同;有2株序列与SHV-11(序列号:AY 293069,41→817)100%相同;有4株序列与SHV-27(序列号:AF 293345,2→821)氨基酸序列完全相同;有1株序列与SHV-28(序列号:AF 538324,12→823)100%相同;有2株序列在G enB ank中未找到与之完全相同的序列。结论本地肺炎克雷伯菌中有SHV-1a、SHV-11、SHV-28广谱β-内酰胺酶基因和SHV-2、SHV-27 ESBL s基因存在。

重症监护病房患者产超广谱β-内酰胺酶细菌感染的耐药性研究

目的 了解我院重症监护病房 (ICU)感染患者标本中肠杆菌科细菌产超广谱 β 内酰胺酶 (ESBLs)的现状 ,为ICU抗感染化疗提供用药依据。方法 对我院 8年来ICU送检标本中分离的 5 6 3株肠杆菌科细菌采用双纸片法筛选试验及确证试验检测ESBLs ,并用K B纸片法进行药敏试验。结果 5 6 3株肠杆菌科细菌中检出产ESBLs菌 115株 ,检出率 2 0 4 % ;肺炎克雷伯菌的产酶率 2 6 1% ,高于大肠埃希菌 18 9%的产酶率 ;肠杆菌、柠檬酸杆菌、变形菌及摩根菌均检出产ESBLs菌株 ;产ESBLs菌株对 15种常用抗菌药物的敏感性明显低于不产ESBLs的菌株 ;亚胺培南对产ESBLs细菌仍具有很高的抗菌活性。结论 我院ICU送检标本中分离的产ESBLs细菌比例高 。

头孢米诺和其他14种抗菌药物对产与不产超广谱β-内酰胺酶菌株抗菌活性比较

目的 测定头孢米诺和其他 14种抗菌药物对产与不产超广谱 β-内酰胺酶 (ESBL s)菌株的体外抗菌活性。方法 采用琼脂稀释法测定头孢米诺和其他 14种抗菌药物的最小抑菌浓度 (MIC) ,纸片确证法检测 ESBL s。结果 对 110株产 ESBL 的大肠埃希菌和肺炎克雷伯菌 ,未发现亚胺培南耐药的菌株 ,除亚胺培南外 ,头孢米诺比其他的 13种抗生素有较低的耐药性 ,其耐药率为 7.3% ,MIC50 和 MIC90 值范围分别为 0 .5～ 1mg/ L 和2～ 32 m g/ L;对 4 0株不产 ESBL s的大肠埃希菌和肺炎克雷伯菌、头孢米诺、头孢美唑、头孢他啶、头孢噻肟、头孢曲松、头孢哌酮、头孢吡肟及亚胺培南 ,有相似的体外抗菌活性 ,其敏感率均为 10 0 % ,MIC50 和 MIC90 值范围分别为 0 .0 32～ 0 .5 mg/ L和 0 .0 6 4～ 4 mg/ L。结论 对产 ESBL 的大肠埃希菌和肺炎克雷伯菌 ,未发现亚胺培南耐药的菌株 ,头孢米诺比其他 β-内酰胺类 ,庆大霉素和氟喹诺酮类有较高的体外抗菌活性 ;对不产 ESBL s的菌株 ,头孢米诺、头孢美唑、头孢他啶、头孢噻肟、头孢曲松、头孢吡肟及亚胺培南有相同的抗菌活性 ,没有耐药的菌株发现。

肺炎克雷伯菌质粒编码的AmpC酶和超广谱β-内酰胺酶的表型和基因型分析

目的研究肺炎克雷伯菌质粒编码的AmpC酶和超广谱β-内酰胺酶(ESBLs)的表型和基因型。方法利用3-氨基苯酚硼酸及ESBLs确认试验检测AmpC酶与ESBLs表型,接合转移试验了解质粒在细菌间的传递;通过质粒的提取、纯化,PCR反应及序列分析,研究肺炎克雷伯菌质粒携带的ampC基因和ESBLs基因类型。结果从肺炎克雷伯菌中获得1条约15 kb大小的质粒,此质粒可通过接合转移方式将耐药性传递至大肠埃希菌,以从肺炎克雷伯菌及接合转移后的接合子细菌中,提取的质粒为模板,均可扩增出DHA型ampC基因及SHV型ESBLs基因,序列分析进一步证实ampC及ESBLs基因型分别为DHA-1型及SHV-12型。结论从肺炎克雷伯菌可转移的质粒中,检测到DHA-1型ampC基因及SHV-12型ESBLs基因。

产超广谱β-内酰胺酶肺炎克雷伯氏菌和大肠埃希氏菌呼吸道感染的临床分析

为探索产超广谱β-内酰胺酶 (ESBL s)的肺炎克雷伯氏菌和大肠埃希氏菌呼吸道感染的临床特点 ,寻找有效的预防和治疗措施 ,对 92株肺炎克雷伯氏菌和大肠埃希氏菌采用双纸片法检测出产 ESBL s的肺炎克雷伯氏菌 2 8株和大肠埃希氏菌株 16株 ,并以是否产 ESBL s分为四组 ,对四组的抗生素耐药性、预后和本次发病前 3个月抗生素使用情况作了初步研究。结果 ,肺炎克雷伯氏菌产 ESBL s率为 47.5 % ,大肠埃希氏菌产 ESBL s率为 48.5 % ;产 ESBL s的肺炎克雷伯氏菌和大肠埃希氏菌对青霉素类 ,第一、二、三代头孢菌素和部分氨基糖苷类有极高的耐药性 ,与不产 ESBL s组相比耐药性高 (P<0 .0 5 ) ,但对阿米卡星和亚胺培南相当敏感 ,对复方新诺明和头孢西丁尚有一定的敏感性 ;产 ESBL s的肺炎克雷伯氏菌和大肠埃希氏菌两组患者本次发病前青霉素类、头孢菌素类、喹诺酮类等抗生素的使用多于不产 ESBL s组 (P<0 .0 5 ) ;产 ESBL s的肺炎克雷伯氏菌和大肠埃希氏菌所致的呼吸道感染患者死亡率高于不产组 (P<0 .0 5 )。结果提示 ,产 ESBL s的肺炎克雷伯氏菌和大肠埃希氏菌的出现可能与各类抗生素的广泛使用有关 ,ESBL s菌引起的感染预后差。治疗 ESBL s菌引起的感染可用亚胺培南、阿米卡星、复方新诺明。