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.

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.

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.

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.

Study on the Genotype of Extended-spectrum Beta-lactamases Mediated by Plasmid in Southern China

To investigate the prevalence and genotype of extended spectrum beta-lactamases (ESBLs) mediated by plasmid in Gram-negative bacteria found in southern China, a total of 1184 clinical isolates of non-repetitive strains of Gram-negative bacteria were collected in 2001 from 5 different cities in southern China. The ESBLs-producing isolates were distinguished by means of the phenotype confirmatory test based on the NCCLS criteria and were subjected to plasmid conjugation and electroporation experiments. Those clinical isolates succeeded in plasmid transfers had undergone plasmid conjugation and electro-transformation, plasmid DNA extraction and PstⅠ digest finger-printing analysis, as well as the universal primer PCR amplification of the TEM, SHV, CTX-M, VEB, PER and SFO genes and the DNA sequencing in order to determine the genotypes of ESBLs and their plasmid locations. It was found that the incidence of the ESBLs-producing strains of Gram-negative bacteria was 14.6% (173/1184) with 67 strains of transconjugants and 11 strains of electro-transformants, in which CTX-M-14 type was 33.3% (26/78); CTX-M-3 type was 23.1% (18/78); CTX-M-9 type was 14.1% (11/78); CTX-M-5 type was 6.4% ( 5/78); CTX-M-13 type was 2.6% (2/78); SHV-5 type was 7.7% (6/78); SHV-12 type was 5.1% (4/78), SHV-2a type was 2.6% (2/78) and unidentified type was 5.1% (4/78). 29.5% of the wild strains also carried broad-spectrum beta-lactamases TEM-1 and SHV-1 types. The above mentioned ESBLs genes were located on transferable plasmids with variable sizes (from 35 to 190?kb). The CTX-M type ESBLs was characterized by high-level of resistance to cefotaxime. It concluded that the CTX-M-type was the most prevalent genotype in clinical isolates of Gram-negative bacteria in southern China, and the SHV-type ranks in the second place. TEM-, VEB-, Toho- and PER-types were not found in these isolates.

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.

Prevalence and Risk Factors of Penicillinase-Type β-Lactamase Producing Neisseria gonorrhoeae Isolated from Patients Attending Health-Facilities in Yaounde, Cameroon

Background and Objectives: Mitigation of antibiotic resistant Neisseria gonorrhoeae has become a priority due to considerable health and economical disabilities it generates. In order to tackle the emergence of resistant Neisseria gonorrhoeae, this study aimed to determine the prevalence and risk factors of penicillinase type β-lactamase-producing Neisseria gonorrheae among patients consulting for genital infectious disorders in two health-facilities in Yaounde, Cameroon. Materials and Method: A cross-sectional descriptive and analytical study was conducted over a 3-month period, from July 2nd to October 2nd, 2022. Vaginal and urethral secretions were collected. Biochemical identification tests were performed on colonies grown on chocolate agar + polyvitex using the Api NH gallery. The detection of penicillinases was equally performed using the API NH gallery and confirmed using the antimicrobial susceptibility testing. The Minimum Inhibitory Concentrations of some antibiotics were determined using the E-Test. Results: The results showed that out of the 198 patients sampled, 16 (8.08%) were positive for Neisseria gonorrhoeae, among which 13/16 (81.25%) were penicillinase-type β-lactamase producers. Antimicrobial susceptibility testing results showed high co-resistances to antibiotics, mainly ciprofloxacin (100%), nalidixic acid (92.31%) and azithromycin (84.62%). Moreover, high Minimum Inhibitory Concentrations of ceftriaxone (ranging from 6 to 24 mg/L) was observed toward Neisseria gonorrhoeae isolates. The risk factors of the carriage of penicillinase-type β-lactamase producing Neisseria gonorrhoeae identified were: a history of Sexually Transmitted infections (p = 0.01) and unprotected sexual intercourse (p = 0.01). Conclusion: The emergence of penicillinase-type β-lactamase producing Neisseria gonorrhoeae is increasing and the situation is becoming worrisome. The identified risk factors can constitute a basic outlook to tackle resistant Neisseria gonorrhoeae, and therefore sustain antibiotic stewardship.

一株多重耐药大肠杆菌全基因组测序及其耐药性分析

为了解大肠杆菌携带的粘菌素耐药基因并筛选敏感药物,解决多重耐药和动物临床无药可选的困局,采用16S rRNA菌种全基因组测序,PCR筛查mcr-4、mcr-5、blaTEM和AmpC酶耐药基因,应用BLAST和MEGA软件进行生物信息学和系统进化树分析,并对该菌株进行了78种抗生素抗菌药物敏感性测试及4种天然植物提取物(黄藤素、黄连素、黄芩苷和博落回)的抑菌、杀菌效果试验。结果表明,从2021年(1—12月)和2022年(1—6月)猪临床腹泻病例肠道中分离鉴定的145株大肠埃希菌(Escherichia coli,E.coli)中,鉴定出1株同时携带粘菌素耐药基因(mcr-4,mcr-5)和β内酰胺酶blaTEM、AmpC基因的猪源大肠埃希氏菌临床菌株HN2149。78种抗生素药敏试验结果显示,HN2149菌株对头孢吡肟、头孢地嗪、磷霉素、头孢克肟、头孢唑林、头孢哌酮、美洛培南、头孢西丁、头孢呋辛、头孢曲松、头孢噻肟、头孢他啶、替卡西林/克拉维酸、头孢哌酮/舒巴坦、氨曲南、哌拉西林/他唑巴坦、头孢噻肟/克拉维酸、头孢唑肟、头孢美唑、头孢他啶/克拉维酸和头孢他美敏感,对其余57种抗菌药物表现为耐药。4种植物提取物的药敏结果显示,博落回对菌株HN2149的抑菌、杀菌效果较好,其余3种提取物均对该菌株无抑菌和杀菌效果。以上研究结果为猪大肠杆菌病的防控提供参考。

家兔支气管败血波氏杆菌的分离鉴定及耐药基因检测

为深入了解兔支气管败血波氏杆菌(Bordetella bronchiseptica,Bb),试验将病兔体内分离得到的菌株进行菌株鉴定、生长曲线测定、致病性研究、药敏试验及耐药基因检测,期望了解该菌的生长规律,为临床用药及防控奠定基础。通过Gram染色镜检、分离培养、16S rDNA序列分析对分离菌株进行鉴定,测定了该分离株的生长曲线、半数致死量、耐药性并对分离菌株进行β-内酰胺酶耐药基因的检测。结果表明:分离得到1株革兰氏阴性杆菌,命名为P201215,该分离株的16S rDNA基因序列与GenBank中支气管败血波氏杆菌(登录号为NR113628.1)的同源性为99%。分离株的对数生长期为2~9 h,9 h后进入平台期;对KM小鼠的半数致死量为1.19×107 CFU。药敏试验结果显示,分离株对部分头孢菌素类药物耐药,对大部分β-内酰胺类、喹诺酮类、四环素类及氨基糖苷类药物敏感,PCR检测未检出超广谱β-内酰胺酶耐药基因。

β-内酰胺酶抑制剂的稳定性与降解反应特性

β-内酰胺酶抑制剂与广谱β-内酰胺抗生素的联合使用是一种有效解决细菌耐药的策略之一。目前上市的β-内酰胺酶抑制剂按其化学结构主要包括氧青霉烯类(克拉维酸)、青霉烷砜类(舒巴坦和他唑巴坦)和二氮杂二环辛烷类化合物(阿维巴坦),本文对临床常见的β-内酰胺酶抑制剂的稳定性与降解反应特性进行综述,并结合当前药典标准中的有关物质检查项,探讨上述β-内酰胺酶抑制剂的杂质谱控制策略。

儿科住院患儿多重耐药菌耐药性分析

目的探讨儿科住院患儿多重耐药菌感染的情况及对抗菌药的耐药性,为临床合理应用抗菌药提供理论依据。方法对2019年1月至2022年12月在海口市妇幼保健院儿科住院多重耐药菌感染的175例患儿临床资料进行回顾性分析。结果9376例患儿共分离病原菌1846株,检出多重耐药菌175株。175例患儿中,男102例,女73例,年龄1个月至5岁,<1岁56例,1~3岁107例,>3岁12例。175株多重耐药菌中,革兰氏阳性菌107株,占61.14%,革兰氏阳性菌中耐甲氧西林金黄色葡萄球菌97株(55.43%),其次是产超广谱β-内酰胺类酶(ESBLs)肺炎克雷伯菌和产ESBLs大肠埃希菌,分别为35株(20.00%)和27株(15.43%)。在标本的类型中,以痰液为主,为163株(93.15%),其次为大便9株(5.14%),药敏结果示耐甲氧西林金黄色葡萄球菌对青霉素、红霉素、头孢西丁、替加环素、苯唑西林、克林霉素耐药率100%,对万古霉素、利福平、利奈唑胺敏感率90%以上;表皮葡萄球菌对青霉素、红霉素、头孢西丁、苯唑西林、替加环素耐药率100%,对万古霉素、利福平、利奈唑胺敏感率80%以上。肺炎克雷伯菌对氨苄西林、氨苄西林/舒巴坦、头孢唑啉、头孢替坦、头孢他啶耐药率80%及以上,对亚胺培南和厄他培南敏感率70%以上;大肠埃希菌对氨苄西林、氨苄西林/舒巴坦、头孢曲松、头孢唑啉耐药率80%以上,对亚胺培南和厄他培南敏感。结论住院患儿多重耐药菌主要发生在1~3岁呼吸道感染的患儿,检测出的多重耐药菌耐药现象严重,应加强对此类患儿的管理及加强对多重耐药菌的检测和耐药性监测,合理使用抗菌药,预防多重耐药菌的产生。

bla_(CMY-2)阳性禽源奇异变形杆菌的多重耐药特征

【目的】研究bla_(CMY-2)阳性禽源奇异变形杆菌的多重耐药特征,并分析菌株CY32全基因组序列结构。【方法】对5株bla_(CMY-2)阳性禽源奇异变形杆菌进行氟苯尼考和质粒介导氟喹诺酮类耐药基因检测、接合试验和bla_(CMY-2)基因的Southern杂交定位,对其中一株菌CY32进行全基因测序和生物信息学分析。【结果】5株奇异变形杆菌携带的bla_(CMY-2)位于染色体,其中,菌株CY12、CY32、S31和S52携带floR,菌株CY12和CY32携带qnrD。CY32的染色体同时含有SXT/R391型整合性接合元件(integrative and conjugative elements,ICEs)(ICEPmiJpn1)和PmGRI1共2种耐药基因岛。ICEs的可变区包含2个串联的复合型转座子(IS10构成),其中一个复合型转座子携带bla_(CMY-2);CY32的PmGRI1耐药岛含有12个耐药基因。与其他奇异变形杆菌携带的PmGRI1相比,多重耐药区差异最大的区域位于Tn21转座子。此外,CY32包含2个质粒,包括携带floR的IncQ质粒和携带qnrD的非接合质粒。奇异变形杆菌CY32携带15个耐药基因,呈现多重耐药的特性。【结论】奇异变形杆菌经基因岛和质粒获得多重耐药,使治疗奇异变形杆菌感染变得更加困难,应加强对动物源奇异变形杆菌耐药性监测。

2015-2021年CHINET儿童患者分离的肠杆菌目细菌耐药性变迁

目的了解2015-2021年CHINET儿童患者分离的肠杆菌目细菌的分布及耐药性变迁。方法采用纸片扩散法或商品化药敏试验自动测试仪器法按照CHINET技术方案进行药敏试验,并采用CLSI 2021年版标准判断结果。结果2015-2021年共收到儿童患者分离的肠杆菌目细菌81681株,占儿童革兰阴性杆菌的50.1%,其中大肠埃希菌、克雷伯菌属和肠杆菌属是最常见的细菌;菌株主要分离自尿液标本(29.3%)和呼吸道标本(27.7%)。儿童大肠埃希菌、肺炎克雷伯菌和奇异变形杆菌的ESBL检出率分别为48.8%~57.6%、49.3%~66.7%和23.1%~33.8%。儿童碳青霉烯类耐药肠杆菌目细菌的检出率为5.7%~9.5%,呈下降趋势,其中碳青霉烯类耐药克雷伯菌属、碳青霉烯类耐药肠杆菌属和碳青霉烯类耐药大肠埃希菌的检出率分别为14.1%~22.6%、7.1%~15.7%和2.0%~3.4%。肠杆菌目细菌对环丙沙星的耐药率高于左氧氟沙星;对阿米卡星、多黏菌素B和替加环素仍具有较好的敏感性。沙门菌属对氨苄西林耐药率>70%,而对头孢曲松耐药率<30%。结论儿童患者分离的肠杆菌目部分细菌(如大肠埃希菌、肺炎克雷伯菌)对常见抗菌药物耐药率呈下降趋势,但需加强细菌耐药性的持续监测,以预防和控制耐药菌的广泛播散。

ICU产超广谱β-内酰胺酶肠杆菌血流感染诊断预测模型的构建和验证

目的:超广谱β-内酰胺酶肠杆菌(extended-spectrumβ-lactamase-producing Enterobacteriaceae,ESBL-E)已成为重症监护室(intensive care unit,ICU)血流感染的主要致病菌之一,严重影响患者的预后。探讨ICU内ESBL-E血流感染的危险因素,构建并验证其诊断预测的模型,可为临床医生在ESBL-E的早期识别、防控提供参考和建议。方法:回顾性分析2020年1月至2022年6月济宁市第一人民医院肠杆菌科细菌血流感染病例的临床资料。将2020年1月至2021年12月收治的患者作为建模组(n=255),2022年1月至6月收治的患者作为验证组(n=51),建模组根据是否产ESBLs将患者分为产ESBLs组(n=131)和非产ESBLs组(n=124),采用多因素Logistic回归分析ESBL-E感染的危险因素,并构建其诊断预测模型,通过受试者操作特征曲线、净重新分类指数、校准曲线、C指数、Brier评分、决策曲线分析和临床影响曲线评估模型的区分度、校准度和获益率,采用Bootstrap法进行内部验证,并通过验证组数据对上述模型进行外部验证。结果:多因素危险因素分析结果显示:急性生理功能和慢性健康状况评价II(acute physiology and chronic health evaluation II,APACHE II)评分(>15)、营养风险筛查2002(nutritional risk screening 2002,NRS 2002)评分(≥3)、2个月内使用过头孢菌素、2个月内使用过喹诺酮类抗生素是ICU中ESBL-E血流感染的独立危险因素。ESBL-E血流感染诊断预测模型回归方程=−1.718+APACHE II评分(>15)×0.989+NRS 2002评分(≥3)×0.989+2个月内使用过头孢菌素×0.648+2个月内使用过喹诺酮类抗生素×0.806。该模型显示出良好的预测能力,预测建模组ESBL-E感染的曲线下面积为0.831(95%CI 0.781~0.881),敏感度为79.4%,特异度为72.6%。净重新分类指数显示该模型优于单一因素模型。Hosmer-lemeshow结果显示感染诊断预测模型的拟合优度较好(P=0.482);采用Bootstrap法重复抽样1000次对该模型进行内部验证,校准曲线趋近于理想曲线,C指数为0.831,Brier评分为0.213。决策曲线分析显示该模型在阈值概率0.07~0.70范围内净获益率均大于0。临床影响曲线显示当阈值概率大于0.7后,预测模型判定为ESBL-E感染高风险人群与实际发生ESBL-E人群高度匹配,证实该预测模型临床有效率高。外部验证中应用该模型预测验证组ESBL-E感染的曲线下面积为0.807,敏感度为80.8%,特异度为80.0%,验证结果与实际一致性较高。结论:ICU患者病情越危重、营养不良、近期应用头孢菌素或喹诺酮类抗生素会增加ESBL-E血流感染的风险。基于APACHE II评分(>15)、NRS 2002评分(≥3)、2个月内使用过头孢菌素或喹诺酮类抗生素构建的诊断预测模型对ICU患者ESBL-E血流感染情况具有较好的预测价值。

农贸市场食品来源大肠埃希菌的耐药性及其ESBL耐药基因的研究

目的:调查云南省保山市农贸市场售卖畜禽肉蛋和蔬菜超广谱β-内酰胺酶(Extended-Spectrumβ-Lactamase,ESBL)大肠埃希菌污染情况,研究样品分离获得的大肠埃希菌ESBL耐药基因类型。方法:收集农贸市场食品样本,分离鉴定样品中的大肠埃希菌并进行药敏试验,扩增大肠埃希菌的ESBL基因,对扩增产物进行测序和同源性比对分析。结果:245份食品样本中分离获得大肠埃希菌75株,其中产ESBL大肠埃希菌25株。对ESBL耐药基因测序结果进行系统发育分析,发现耐药基因为CTX-M型,CTX-M-15序列有9株,占比为36%;CTX-M-14有16株,占比为64%。结论:肉类和蔬菜携带ESBL大肠埃希菌,多重耐药菌及其耐药基因可能通过食品在社区传播。

肺炎克雷伯菌致下呼吸道感染患者常用抗菌药物的耐药性分析

目的分析肺炎克雷伯菌(Klebsiella pneumoniae,KPN)致下呼吸道感染(lower respiratory tract infection,LRI)患者对常用抗菌药物的耐药性。方法选取2022年10月至2023年9月我院KPN致LRI患者514例,采集痰标本,统计KPN、超广谱β-内酰胺酶(EBLS)+菌株、EBLS菌株、耐碳青霉烯类肺炎克雷伯菌(CRKP)检出情况,行药敏试验,分析KPN、EBLS+菌株、EBLS菌株及CRKP菌株对常用抗菌药物的耐药性。结果分离出514株KPN,其中EBLS+菌株94株(18.3%)、EBLS菌株310株(60.3%)、CRKP菌株110株(21.4%);KPN对替加环素最为敏感,达99.8%;EBLS+菌株对大部分常用抗菌药物的耐药率较EBLS菌株高;除替加环素外,CRKP菌株对其他常用抗菌药物的耐药率均较高,>80.0%。结论KPN致LRI患者中分离出EBLS+菌株、EBLS菌株及CRKP菌株,不同菌株对不同抗菌药物耐药率不同,需进行细菌培养与鉴定,了解其耐药率,帮助临床医师合理选择抗菌药物进行治疗。

某三甲医院细菌耐药健康及经济负担研究——以产超广谱β-内酰胺酶大肠埃希菌为例

目的 细菌耐药是全世界共同面对的公共健康难题,产生了严重的健康及经济威胁。本研究从医院视角进一步明确产超广谱β-内酰胺酶(ESBLs)大肠埃希菌感染导致的健康及经济负担,以期为细菌耐药相关政策干预的评估与优化提供实证依据。方法 选取江西省某三甲医院出院时间在2018—2019年的170,819住院人次样本为研究对象,并设置了ESBLs阳性感染组、ESBLs阴性感染组和无感染及定植组。采用倾向得分匹配(propensity score matching, PSM)对3个组进行1:1:100匹配,并采用Cox比例风险回归模型、多状态模型分别测算ESBLs阳性感染组相对于两对照组的死亡风险比(hazard ratio, HR)和额外床日数,最终基于医院视角测算额外住院成本。结果 经匹配后纳入分析的ESBLs阳性感染组、ESBLs阴性感染组和无感染及定植组的样本分别为885、885和81,245住院人次。ESBLs阳性感染组的死亡风险是无感染及定植组的2.58倍(P<0.001),同ESBLs阴性感染者相比并未显著增大患者的死亡风险(P=0.25)。ESBLs阳性感染组相较于其无感染及定植组和ESBLs阴性感染组产生的额外床日数分别为每例3.69 d和1.92 d,对应的额外住院成本为每例6,570.12元和3,418.60元。结论 产ESBLs大肠埃希菌感染会增加患者死亡风险,延长住院时间并加重患者的经济负担,应采取措施进行防控。

北京地区犬猫尿源奇异变形杆菌耐药性及生物被膜形成能力分析

为调查北京地区犬猫尿源奇异变形杆菌对临床常用抗菌药的耐药现状,并分析其对β-内酰胺类药物的主要耐药机制,本试验于2018—2019年采集北京地区16只犬和13只猫的符合菌尿标准的尿液样本,以及264株犬源和152株猫源尿液中未鉴定细菌分离株;分离鉴定奇异变形杆菌,检测其对临床常用的12种抗菌药的耐药性,并分析奇异变形杆菌携带β-内酰胺酶的情况和生物被膜形成能力。结果显示,共分离获得44株犬源(15.7%)和5株猫源(3.0%)奇异变形杆菌。奇异变形杆菌分离株对阿奇霉素和多西环素耐药率均为98.0%,对β-内酰胺类药物耐药率为6.1%~73.5%,多重耐药率为79.6%。28株分离株携带超广谱β-内酰胺酶(ESBLs),阳性率为57.1%,主要基因型为bla TEM型、bla CTX-M-9型和bla OXA-1型;1株分离株携带头孢菌素酶(AmpC),基因型为bla CMY-2型。产ESBLs菌株对氨苄西林、氯霉素、头孢吡肟、头孢曲松和庆大霉素的耐药率显著高于非产ESBLs菌株的耐药率(P<0.05)。奇异变形杆菌分离株形成生物被膜阳性率为100%,其生物被膜形成能力强度与所选抗菌药的耐药性无明显相关性(P>0.05)。结果表明,北京地区犬猫尿源奇异变形杆菌耐药情况严重,携带ESBLs阳性率较高,形成生物被膜阳性率达100%,临床用药时可选择耐药率较低的阿莫西林克拉维酸进行治疗。