8种氨基糖苷类抗生素FDNB衍生化产物的电喷雾离子阱质谱及色谱行为研究

 目的 采用电喷雾离子阱质谱（ESI-MSn法研究8种氨基糖苷类抗生素2,4-二硝基氟苯（FDNB衍生化产物的质谱裂解规律及色谱行为。方法 分别取氨基糖苷类抗生素FDNB衍生化产物溶液,将其直接导入ESI离子源进行分析。结果 在正离子检测方式下,各化合物在二级质谱分析时,均可发生A环与B环之间的糖苷键断裂,生成脱去A环的碎片离子;在三级质谱分析时,进一步发生B环与C环之间的糖苷键断裂,生成脱去B环或C环的碎片离子。新霉素B由4个环组成,在三级质谱分析时,其衍生化产物发生B环与C环之间的糖苷键断裂,主要生成脱去B环的碎片离子;在四级质谱分析中,进一步生成脱去C环或D环的碎片离子。结论 通过LC-MS/MS和HPLC-UV分析获得了氨基糖苷类抗生素FDNB衍生化产物的色谱行为信息,为该类药物分析方法（HPLC-UV和LC-MS/MS的建立和结构解析提供依据。     

氨基糖苷类修饰酶基因在我院分离产超广谱β内酰胺酶肺炎克雷伯菌中的表达

目的 调查氨基糖苷类修饰酶（AMEs）基因在泰安中心医院院内分离的产超广谱β内酰胺酶（ESBL）肺炎克雷伯菌中的表达情况,为合理使用抗菌药物提供依据.方法 采用多聚酶链反应（PCR）方法,检测aac（3）-Ⅰ、aac（3）-Ⅱ、aac（3）-Ⅲ、aac（3）-Ⅳ、aac（6＇）-Ⅰ、ac（6＇）-Ⅱ、aph（3＇）-Ⅵ、ant（3＂）-Ⅰ和ant（2＂）-Ⅰ等9种AMEs,在42株院内分离的产ESBL肺炎克雷伯菌中的表达情况.结果 42株产ESBL肺炎克雷伯菌中,36株（85.7%）携带aac（3）-Ⅱ基因,25株（59.5%）携带ant（3＂）-Ⅰ基因,9株（21.4%）携带aac（6＇）-Ⅰ基因,4株（9.5%）携带aph（3＇）-Ⅵ基因,3株（7.1%）携带aac（3）-Ⅰ基因,AMEs携带率为90.5%（38/42）.结论 我院院内分离的产ESBL肺炎克雷伯菌的AMEs基因携带率很高,其对氨基糖苷类药物耐药可能与AMEs有关.     

长春地区部分医院革兰阴性杆菌氨基糖苷类修饰酶基因的检测

目的：分析长春地区部分医院革兰阴性杆菌氨基糖苷类修饰酶基因的分布和类型,为抗生
素的合理应用提供依据。方法：通过琼脂稀释法筛选出阿米卡星与庆大霉素的耐药菌株,采用聚合
酶链式反应及序列分析的方法检测耐药菌株所携带的氨基糖苷类修饰酶基因类型。结果：69株革兰阴性杆菌对阿米卡星与庆大霉素的耐药率分别为44.9%和87.0%,其中63株 (91.3%) 检出氨基糖苷类修饰酶基因,基因类型包括aac(3)-Ⅰ、aac(3)-Ⅱ、aac(6′)-Ⅰb、ant(3")-Ⅰ和
ant(2")-Ⅰ,阳性率分别为4.3%、81.2%、43.5%、33.3%和13.0%;而aac (6′)-Ⅱ基因为阴性。结论：本地区革兰阴性杆菌氨基糖苷类修饰酶基因主要以aac(3)-Ⅰ、aac(3)-Ⅱ、aac(6′)-Ⅰb、ant(3")-Ⅰ和ant(2")-Ⅰ  5种类型存在,其中以aac(3)-Ⅱ型氨基糖苷类修饰酶基因最为常见。合理应用氨基糖苷类抗生素对于降低细菌的耐药性具有重要意义。
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Nosocomial Spread of ArmA-Mediated High-Level Aminoglycoside Resistance in Enterobacteriaceae Isolates Producing CTX-M-3 β-Lactamase in a Cancer Hospital in Bulgaria

Abstract

1,310 Enterobacteriaceae 242 Pseudomonas aeruginosa and 97 Acinetobacter baumannii clinical isolates collected at a cancer hospital in Bulgaria were screened for the presence of 16S rRNA methylases. The armA methylase gene was identified in 20 (1.5%) Enterobacteriaceae (7 Klebsiella pneumoniae, 3 Escherichia coli, 3 Serratia marcescens, 3 Citrobacter freundii, 3 Enterobacter cloacae and 1 Klebsiella oxytoca). ArmA-mediated aminoglycoside resistance was transferable by conjugation and carried by closely related IncL/M plasmids which also carried ant3”9, dfrXII, sul1, bla _TEM-1, and bla _CTX-M-3 genes encoding resistance to streptomycin-spectinomycin, trimethoprim, sulfonamides, and β-lactams, respectively. Most of the isolates were genetically different according to PFGE but shared similar restriction patterns of the armA-encoding plasmids. Our findings highlight the strong association of armA and bla _CTX-M-3 extended-spectrum β-lactamase genes across various species in the family Enterobacteriaceae. The spread of multiresistant isolates expressing 16S rRNA methylases and ESBLs is a worrisome development requiring continuous monitoring.     

鲍曼不动杆菌对氨基糖苷类药物的耐药机制研究

目的探讨鲍曼不动杆菌对氨基糖苷类药物耐药机制。方法K-B法检测19株鲍曼不动杆菌对4种氨基糖苷类药物的敏感性,聚合酶链反应(PCR)检测氨基糖苷类修饰酶基因。结果14株鲍曼不动杆菌携带aacA4基因,检出率为74%。结论aacA4型氨基糖苷类修饰酶是鲍曼不动杆菌对氨基糖苷类药物耐药的重要机制。     

高效液相色谱—蒸发光散射检测法测定氨基糖苷类抗生素中硫酸盐含量的研究

目的:建立高效液相色谱-蒸发光散射检测法测定氨基糖苷类抗生素中硫酸盐的含量。方法:采用ODS柱,以含0.015mol·L-1正已胺和0.025mol·L-1甲酸的水-乙腈（88:12）为流动相,流速为10mL·min-1,蒸发光散射检测,检测器温度:45℃,雾化气体（空气）压力:0.35 MPa。结果:SO42-在22～435μg·mL-1范围内呈良好的线性关系,r=0.9997;平均回收率为99.8％,RSD=0.31％（n=6）;日内精密度（RSD=1.1％,n=8）良好。结论:本方法简便,快速,结果准确,可靠,重现性好。     

Identification and antibiotic resistance of faecal enterococci isolated from water samples

We have isolated 47 strains of presumptive faecal streptococci from different water samples. Identification was made by the method of Facklam et al. (1989). Antibiotic resistance was studied on Mueller-Hinton Agar. Twelve antibiotics were tested. High-level aminoglycoside resistance (HLAR) and resistance to glycopeptides were studied. Biochemical identification of presumptive faecal streptococci isolates gave the following results: 19 Enterococcus faecalis, 12 E. faecium, 8 E. hirae, 4 E. durans and 4 E. mundtii. E. mundtii is not included among faecal enterococci. None of the strains were resistant to glycopeptides (vancomycin and teicoplanin). Three strains of Enterococci showed HLAR. Two of them were isolated from coastal bathing waters and the other from wastewater. This suggests that water could contribute to spread of HLAR enterococci and it should be a matter of concern for public health authorities.     

Toll-like receptor-2 mediates systemic inflammation in gentamicin-induced rat nephrotoxicity

Gentamicin is an aminoglycoside antibiotic commonly administrated to patients with Gram-negative infections. Gentamicin induced nephrotoxicity by functional and structural impairment. Toll-like receptors (TLRs) as key mediators in the innate and adaptive immune system response involved in gentamicin-induced nephrotoxicity. The present study aimed to investigate the gene expression of TLR2 and pro-inflammatory cytokines in the renal tissues and buffy coat of the whole blood in gentamicin-treated rats. Twenty adult male Sprague Dawley rats weighing 180–200 were randomly divided into gentamicin (100 mg/kg, i.p) and control groups (n = 10). After 10 days, the serum creatinine (Cr) levels and blood urea nitrogen (BUN) were measured. The mRNA levels of TLR2, tumour necrosis factor (TNF)-α, interleukin (IL)-1β, and monocyte chemoattractant peptide (MCP)-1 were investigated in the renal tissue and buffy coat by qRT-PCR. Kidney histological analysis performed by hematoxylin-eosin (H&E) staining. Functional disturbance is characterized by a significant increase in the serum levels of Cr and BUN in the gentamicin group. Renal tissue slides of the gentamicin group indicated severe glomerular and tubular damage including lobulation of the glomerular tuft, Bowman's space enlargement, acute tubular necrosis, and proximal tubular destruction. The mRNA levels of IL-1β, TNF-α, MCP-1, and TLR2 increased in the buffy coat, but all of them except TLR2 decreased in the renal tissues in the gentamicin group compared with controls. Gentamicin administration induced relative systemic inflammation, which may be related to an increase in the mRNA levels of TLR2 results in gene expression of pro-inflammatory chemokines and cytokines including IL-1β, TNF-α, and MCP-1 in immune cells.     

Interactions Between Aminoglycosides and Phospholipids Using Liposomes: A Possible Mechanism of Nephrotoxicity

Interactions of aminoglycosides with phospholipids were estimated by the increase in turbidity of liposomes consisting of various phospholipids. The turbidity of liposomes containing negatively charged phospholipids was increased by gentamicin, the highest increase in turbidity being observed for phosphatidylinositol-4,5-diphosphate-containing liposomes. The extent of turbidity was dependent on the concentration of acidic phospholipid in the liposomal membrane as well as the number of amino groups of the aminoglycosides. The release of glucose from glucose-entrapped liposomes depended on the concentration of gentamicin. The turbidity of liposomes containing lipids extracted from rat renal cortex was also increased by aminoglycosides depending on the number of amino groups. From electron microscopic observations, the increase in turbidity of liposome suspensions was caused by liposome fusion.