头孢菌素C的新型双水相萃取

应用新型双水相体系萃取头孢菌素C。考察了不同亲水有机溶剂/无机盐双水相体系对头孢菌素C的萃取效果,确定使用乙醇/硫酸铵双水相体系。随后,考察了影响该体系萃取效果的主要因素,并将结果应用于发酵滤液的萃取。结果显示,固定乙醇浓度20.0%、硫酸铵浓度27.0%,该体系对头孢菌素C的萃取效果较好,萃取3次的总收率大于94%。     

第三代头孢菌素临床应用的定位

第三代头孢菌素品种多、药理学特点优良、安全性好,在细菌性感染的防治中发挥着重要的作用。但不规范的使用导致产超广谱β-内酰胺酶(ESBLs)菌株的检出率及细菌耐药率有增高的趋势,也使碳青霉烯类等新型抗菌药物的用量增加,导致病原菌耐药加剧,使一些细菌感染的治疗更加困难。但因此而轻视第三代头孢菌素的临床价值是不正确的。综合致病菌种类、药敏试验结果、感染特点与病人状况等因素,审慎选择和使用第三代头孢菌素,充分发挥其临床应用价值,在当下仍具有积极的意义。本文从药物品种、优缺点、主要致病菌的耐药情况以及临床定位等几个方面,对第三代头孢菌素作一梳理,供临床医师、药师参考。     

Evaluation of disk diffusion methods to detect low-level β-lactamase-negative ampicillin-resistant Haemophilus influenzae

We evaluated the efficacy of disk diffusion methods for detection of low-level β-lactamase-negative ampicillin-resistant (low-BLNAR) Haemophilus influenzae. Four hundred and seventy unselected, recent clinical isolates were tested with ampicillin (10 μg), cefaclor (30 μg) and cefuroxime (30 μg) on iso-Sensitest agar enriched with nicotinamide adenine dinucleotide (NAD) and horse blood [ST agar; Swedish Reference Group for Antibiotics (SRGA) guidelines], and on chocolate agar (in-house guidelines). Selected isolates (n = 147) were subjected to partial sequencing of the ftsI gene. Forty-seven strains (10.0%) were genotypically identified as low-BLNAR, which was confirmed by determination of minimal inhibitory concentration (MIC) using microbroth dilution method: only low level resistance to ampicillin was detected [MIC ≤1 μg/mL; MIC(50) = 0.5 μg/mL, implying susceptibility by Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antibiotic Susceptibility Testing (EUCAST) interpretative criteria]. The MIC of cefuroxime varied between 1 and 4 μg/mL (MIC(50) = 2 μg/mL), indicating susceptibility to cefuroxime by CLSI but not by EUCAST guidelines. Disk diffusion methods were able to discriminate low-BLNAR H. influenzae from the wild-type population with sensitivities ranging from 87% to 98% and specificities from 96% to 99%. Cefaclor was found to be superior to cefuroxime and ampicillin. Cefaclor zone diameter breakpoints of 30/29 and 23/22 mm are suggested for ST agar and chocolate agar, respectively.     

耐三代头孢肺炎克雷伯菌感染者血流感染的流行病学及危险因素分析（2015—2019年）

目的:了解耐三代头孢肺炎克雷伯菌（3GCR-Kp）血流感染的流行病学特征及其感染的危险因素,为预防和治疗该类菌的感染提供依据。方法:收集重庆市大足区人民医院2015—2019年血流感染肺炎克雷伯菌患者的病例资料,根据是否对三代头孢（头孢曲松或头孢他啶）耐药分为耐药组（56例）和敏感组（102例）,并选取与敏感组等比例的...     

Natural evolution of skin‐test sensitivity in patients with IgE‐mediated hypersensitivity to cephalosporins

There are studies demonstrating that skin‐test sensitivity to penicillins can decrease over time and that allergic patients may lose sensitivity if the responsible compounds are avoided. With regard to subjects with IgE‐mediated hypersensitivity to cephalosporins, however, such studies are lacking. We evaluated prospectively in a 5‐year follow‐up 72 cephalosporin‐allergic patients. After the first evaluation, patients were classified into two groups according to their patterns of allergologic‐test positivity: to both penicillins and cephalosporins (group A), or only to cephalosporins (group B). Skin tests and serum‐specific IgE assays were repeated 1 year later and, in case of persistent positivity, 3 and 5 years after the first allergologic examination. Seven (43.7%) of the 16 subjects of group A and 38 (67.8%) of the 56 patients of group B became negative; one was lost to follow‐up. Patients of group B became negative sooner and more frequently than group A subjects.     

Synthesis of [2H6]ceftazidime as a stable isotopically labeled internal standard

Ceftazidime is a third generation cephalosporin antibiotic that has activity against a wide range of Gram‐negative and Gram‐positive bacterial pathogens, including Escherichia coli and Pseudomonas aeruginosa. Stable isotope‐labeled ceftazidime was required for use as an internal standard in LC‐MS/MS assays, and a route was developed to make [²H₆]ceftazidime in eight steps from the commercially available labeled starting material [²H₇]isobutyric acid.     

Compassionate Use of Cefiderocol in the Treatment of an Intraabdominal Infection Due to Multidrug-Resistant Pseudomonas aeruginosa: A Case Report

Multidrug-resistant (MDR) Pseudomonas aeruginosa infections often represent a therapeutic challenge requiring utilization of older, more toxic antibiotics, or new agents with limited data. Once susceptibility to β-lactam and fluoroquinolone antibiotics has been lost, other therapeutic options such as aminoglycoside or polymyxin antibiotics carry significant adverse effects such as nephrotoxicity, neurotoxicity, and ototoxicity. A novel cephalosporin, cefiderocol, lacks gram-positive and anaerobic activity but offers broad coverage of gram-negative bacteria, including P. aeruginosa. A unique catechol side chain gives it activity as a siderophore, thereby increasing bacterial uptake and decreasing efflux. Additionally, cefiderocol is stable against a wide array of β-lactamases. Despite these promising characteristics, there are minimal data currently available in the literature detailing the use of cefiderocol in the treatment of MDR P. aeruginosa infections. We present a case of a 46-year-old man who developed an MDR P. aeruginosa intraabdominal infection where serious and life-threatening toxicities to aminoglycosides and polymyxin antibiotics led to the utilization of cefiderocol on compassionate use approval. The isolate was susceptible to cefiderocol, and the patient was treated for 28 days of therapy. He demonstrated clinical and radiographic resolution of his infection and was discharged to home.