Bacterial resistance to antibiotics: modified target sites

Alteration in the target sites of antibiotics is a common mechanism of resistance. Examples of clinical strains showing resistance can be found for every class of antibiotic, regardless of the mechanism of action. Target site changes often result from spontaneous mutation of a bacterial gene on the chromosome and selection in the presence of the antibiotic. Examples include mutations in RNA polymerase and DNA gyrase, resulting in resistance to the rifamycins and quinolones, respectively. In other cases, acquisition of resistance may involve transfer of resistance genes from other organisms by some form of genetic exchange (conjugation, transduction, or transformation). Examples of these mechanisms include acquisition of the mecA genes encoding methicillin resistance in Staphylococcus aureus and the various van genes in enterococci encoding resistance to glycopeptides.     

金黄色葡萄球菌norA基因的研究

目的 研究norA基因介导的金葡菌对氟喹诺酮类药物的耐药机制。方法PCR法制备DIG-norA基因探针；点杂交及狭线杂交检测细菌nor4基因及其转录水平。结果所有实验菌株均检测到norA基因；诱导耐药菌SA2-16的norA基因转录水平明显高于其亲代株，临床分离耐药菌norA基因转录水平略高于敏感菌，但统计学分析无显著性差异，细菌在环丙沙星1／10MIC浓度中生长，未见norA基因转录增加。结论 norA基因可能为金葡菌的结构基因，诱导耐药菌药物泵出增加的原因在于norA基因转录的增加，norA基因介导的耐药在不同的耐药菌株中所起的作用并不相同。     

Mohnarin2006——2007年度报告：尿标本细菌耐药监测研究

目的了解我国尿路感染细菌分布及耐药状况。方法采用纸片法、MIC法或E-test法,使用WHONET5.4软件进行分析,对卫生部全国细菌耐药性监测网(Mohnarin)所属84家三级甲等医院2006年6月1日~2007年5月31日从尿标本中分离的菌株进行分析。结果1共分离菌株15167株,其中革兰阳性菌4160株,革兰阴性菌11007株,分别占27.4%和72.6%。分离量最多的为大肠埃希菌6838株(45.1%)、肠球菌属2222株(14.7%)和肺炎克雷伯菌1035株(6.8%);2大肠埃希菌和肺炎克雷伯菌对氟喹诺酮类的耐药率分别为70%和45%;对头孢噻肟耐药率分别为45.2%与42.5%;3屎肠球菌对各种抗菌药物的耐药率明显高于粪肠球菌,粪肠球菌、屎肠球菌中分别有1.2%、3.2%对万古霉素耐药,有1.4%、3.9%对替考拉宁耐药;4表葡菌和金葡菌对头孢西丁的耐药率分别为74.4%和36.0%,未发现对糖肽类中介或耐药的金葡菌,表葡菌对替考拉宁有3.9%的中介率。结论我国尿路感染主要致病菌以大肠埃希菌为代表的革兰阴性杆菌为主,但肠球菌等革兰阳性菌所占比例有所增多;致病菌对喹诺酮类、第三代头孢菌素的耐药率进一步升高。     

新生儿重症监护室金黄色葡萄球菌定植菌株的耐药性及生物膜形成能力研究

摘要：目的 研究北京儿童医院新生儿重症监护病房(NICU)患儿鼻前庭金黄色葡萄球菌(简称金葡菌)的定植情况及定植菌 株的药物敏感性、生物膜形成能力。方法 前瞻性收集2015年5月至2016年3月于北京儿童医院NICU住院患儿鼻前庭分离出的 金葡菌,前期已进行分子分型,本次实验利用E-test 法检测金葡菌对临床常用抗菌药物的药物敏感性,结晶紫染色实验检测定 植菌株的生物膜形成能力。结果 536例鼻拭子分离出96株金葡菌,定植率为17.9%。其中,耐甲氧西林金葡菌(MRSA) 28株, 甲氧西林敏感金葡菌(MSSA)有68株。MRSA菌株对青霉素、苯唑西林、头孢曲松、红霉素和夫西地酸耐药率分别为100%、 57.1%、78.6%、92.9%和3.6%。MSSA菌株对青霉素、头孢曲松、红霉素、庆大霉素的耐药率分别为82.4%、8.8%、47.1%和 16.2%。MRSA中有14.3%苯唑西林敏感甲氧西林耐药金葡菌(OS-MRSA)。定植菌株的生物膜阳性率91.7%,MRSA和MSSA在生 物膜形成能力方面没有显著差异,不同ST型菌株生物膜形成能力存在差异(P=0.0276),产膜菌株与非产膜菌株的药物敏感性无 明显差异。结论 定植的金葡菌常对青霉素、红霉素耐药,对其他临床常用抗菌药物敏感性较好,有一定比例OS-MRSA。定 植菌株生物膜阳性率高,不同分型菌株生物膜形成能力不同。     

The in-vitro antimicrobial effect of non-antibiotics and putative inhibitors of efflux pumps on Pseudomonas aeruginosa and Staphylococcus aureus

The anti-microbial activity of six non-antibiotics (one amino-ethylchloride, three phenothiazines, two tricyclic antidepressives) were tested on 20 clinical isolates of Pseudomonas aeruginosa, one clinical isolate of Klebsiella pneumoniae, 2 ATTC strains and 14 clinical isolates of Staphylococccus aureus, using the plate dilution method. The effects on P. aeruginosa were independent of antibiotic resistance pattern and the species Stenotrophomonas maltophilia was found to be the most susceptible to the non-antibiotics, with MIC values as low as 20 mg/l for some of the substances. The 16 S. aureus strains tested were all particularly susceptible to the anti-microbial effects of the putative inhibitors of efflux pumps thioridazine and trifluoperazine with MIC values of < or =16 mg/l independently of the methicillin resistance profile of the strains. Because phenothiazines are well known to inhibit efflux pumps our results may indicate the existence of such pumps. Current works in progress are attempts at reversing the antibiotic resistance of selected bacterial strains using specific non-antibiotics and their stereo-chemical isomers.     

Higher biofilm formation in multidrug-resistant clinical isolates of Staphylococcus aureus

The biofilm-forming capacity of Staphylococcus aureus contributes to antibiotic resistance, but whether antibiotic-resistant strains have the capacity to form biofilms has not yet been determined. Therefore, we recovered 101 clinical isolates of S. aureus and performed antibiotic susceptibility testing for 30 antibiotics using a VITEK II automatic system. We then carried out a biofilm assay on 96-well polystyrene plates. In addition, the presence of IS256 involved in the variation of biofilm phases of S. aureus was determined by polymerase chain reaction. The prevalence of IS256 was significantly related to multidrug resistance as well as biofilm expression, with biofilm positivity in 27 (39.7%) of the 68 IS256-positive strains and 3 (9.1%) of the 33 IS256-negative strains. In our analysis of the relationship between meticillin resistance and biofilm formation, we found that the rate of biofilm positivity was 37.9% (25/66) for meticillin-resistant strains and 14.3% (5/35) for meticillin-susceptible strains (P<0.05). Staphylococcal cassette chromosome mec (SCCmec) typing found that SCCmec type IV was most prevalent, comprising 14 (56.0%) of the 25 biofilm-positive, meticillin-resistant strains. A statistical analysis testing the relationship between multidrug resistance and biofilm formation revealed a significantly higher rate of biofilm development in strains with greater multiresistance compared with strains with less multiresistance. Our results suggest that the multidrug-resistant clinical isolates of S. aureus have a greater likelihood of developing biofilms on medical devices.     

Molecular epidemiology of clinically significant antibiotic resistance genes

Antimicrobials were first introduced into medical practice a little over 60 years ago and since that time resistant strains of bacteria have arisen in response to the selective pressure of their use. This review uses the paradigm of the evolution and spread of beta-lactamases and in particular beta-lactamases active against antimicrobials used to treat Gram-negative infections. The emergence and evolution particularly of CTX-M extended-spectrum beta-lactamases (ESBLs) is described together with the molecular mechanisms responsible for both primary mutation and horizontal gene transfer. Reference is also made to other significant antibiotic resistance genes, resistance mechanisms in Gram-negative bacteria, such as carbepenamases, and plasmid-mediated fluoroquinolone resistance. The pathogen Staphylococcus aureus is reviewed in detail as an example of a highly successful Gram-positive bacterial pathogen that has acquired and developed resistance to a wide range of antimicrobials. The role of selective pressures in the environment as well as the medical use of antimicrobials together with the interplay of various genetic mechanisms for horizontal gene transfer are considered in the concluding part of this review.     

铜绿假单胞菌与金黄色葡萄球菌耐药性分析

目的了解近年来铜绿假单胞菌和金黄色葡萄球菌医院感染的分布及耐药情况，为病原学调查及临床治疗提供依据。方法菌株按细菌检验常规方法培养与鉴定，采用纸片扩散法进行药敏实验。结果铜绿假单胞菌的耐药率依次为环丙沙星16.9%，阿米卡星20.0%，亚胺培南22.8%，哌拉西林30.9%，头孢曲松33.6%，头孢哌酮36.4%，庆大霉素64.8%。金黄色葡萄球菌耐药率为万古霉素11.0%，环丙沙星25.4%，阿莫西林/克拉维酸钾29.8%，苯唑西林47.9%，红霉素71.8%，青霉素78.9%。结论铜绿假单胞菌和金黄色葡萄球菌是医院感染主要病原菌，对多种抗生素呈耐药趋势。     

中国西部地区脑脊液细菌分布及耐药性分析

目的 了解2016—2017年中国西部脑脊液分离菌的分布及耐药性。方法 中国西部10家医院脑脊液分离株,按统一 方案用纸片扩散法或自动化仪器进行抗菌药物敏感性试验,按CLSI(美国临床实验室标准化协会)2016年版标准判断结果。结果 10家医院2016—2017年脑脊液标本分离细菌1234株,其中革兰阳性菌697株,占56.5%,革兰阴性菌537株,占43.5%。最常见的 分离菌依次为凝固酶阴性葡萄球菌、鲍曼不动杆菌、肺炎克雷伯菌、屎肠球菌、大肠埃希菌、粪肠球菌、肺炎链球菌、醋酸钙 不动杆菌、铜绿假单胞菌和金黄色葡萄球菌。脑脊液标本中MRSA和MRCNS的检出率分别为27.9%和66.7%,未发现对万古霉 素、替考拉宁和利奈唑胺耐药菌株;粪肠球菌和屎肠球菌对万古霉素的耐药率分别为2.2%和1.6%;大肠埃希菌、肺炎克雷伯菌 中产超广谱β-内酰胺酶(ESBL)菌株的检出率分别为64.2%和58.1%,肺炎克雷伯菌对碳青霉烯类抗生素的耐药率(22.2%~23.6%) 高于大肠埃希菌(3.6%~4.4%),铜绿假单胞菌对碳青霉烯类的耐药率45%以上,鲍曼不动杆菌对碳青霉烯类的耐药率高达85%以 上。结论 脑脊液分离株对常用抗菌药物耐药性严重,碳青霉烯耐药革兰阴性菌的出现和增多,给脑脊液感染的治疗带来极大 挑战,应合理使用抗菌药物,加强医院感染控制,抑制耐药菌的传播。     

Methicillin-resistance in Staphylococcus aureus - molecular basis, novel targets and antibiotic therapy

Methicillin-resistant S. aureus are the major cause of nosocomial bacteremias showing a high morbidity rate in intensive care units. These strains are often resistant against almost all antibiotics in clinical use with the exception of vancomycin. However, the first isolation of a S. aureus strain with a diminished susceptibility to vancomycin from a hospitalized patient in Japan has been reported very recently. Therefore, current antibiotic therapy is difficult and expensive, often a combination of several antibiotics has to be used. For this reason novel antibiotics to combat staphylococcal bacteremias, which prevent further spread of resistance are urgently needed. One approach might be the investigation of the mechanism of methicillin resistance, which is mediated by PBP2a, an additional penicillin-binding protein present in resistant strains with low affinity to ss-lactams. Beside PBP2a other housekeeping genes, the so called fem factors, are involved in expression of methicillin resistance. Two of these fem factors, the FemAB proteins, have been shown to participate in the formation of the pentaglycine crossbridge, which is a unique staphylococcal cell wall component. The biosynthesis of the pentaglycine side chains is not fully elucidated, but follows an interesting novel mechanism with unusual glycyl-tRNA as a substrate. Furthermore, inactivation of femAB, which have been reported as essential for bacterial growth, causes a completely restoration of antibiotic susceptibility in MRSA strains. Thus, these proteins might serve as attractive novel anti-staphylococcal targets for a small-range antibiotic.     

Vancomycin resistance in staphylococci.

Recent emergence of vancomycin resistance in methicillin-resistant Staphylococcus aureus (VRSA) has posed a new threat to hospital infection control and antibiotic chemotherapy. Relatively low-level resistance of VRSA compared to that of vancomycin-resistant enterococci (VRE), and prevalence of S. aureus clinical strains heterogeneously resistant to vancomycin (hetero-VRSA), challenge the value of routine antibiotic susceptibility tests as a tool for the prediction of clinical efficacy of vancomycin therapy. This review summarizes the history of emergence of glycopeptide resistance in staphylococci and considers the mechanism of resistance in these organisms.     

河北邢台市人民医院2017年细菌耐药性监测#br#

目的 了解2017年河北邢台市人民医院临床所有分离细菌的分布情况及耐药性监测。方法 采用自动化仪器法或纸片扩散法(Kirby-Bauer法)对河北邢台市人民医院在2017年临床分离菌株进行药物敏感实验,参照2016版CLSI标准判定结果,并采用WHONET 5.6软件统计分析。结果 2017年共收集细菌4413株,其中革兰阴性菌3368株,占76.3%。革兰阳性菌1045株,占23.7%。革兰阴性菌数量居前5位的是大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌、鲍曼不动杆菌和流感嗜血菌;革兰阳性菌数量居前5位是金黄色葡萄球菌、肺炎链球菌、表皮葡萄球菌、粪肠球菌和溶血葡萄球菌。产超广谱β-内酰胺酶(ESBLs)大肠埃希菌和肺炎克雷伯菌的检出率分别是74.9%(716/956)和44.7%(246/550),产ESBL株对测试药物的耐药率均比非产ESBL株高。肠杆菌科细菌对碳青霉烯类抗生素仍高度敏感,耐碳青霉烯类大肠埃希菌和肺炎克雷伯菌的检出率分别是0.8%(8/956)和4.9%(27/550)。耐碳青霉烯类铜绿假单胞菌的检出率是27.7%(146/528)。鲍曼不动杆菌耐碳青霉烯类的检出率是63.2%(275/435)。金黄色葡萄球菌和凝固酶阴性葡萄球菌的甲氧西林耐药株的检出率分别是43.5%和85.0%,甲氧西林耐药株(MRSA和MRCNS)对多数测试药物的耐药率均显著高于甲氧西林敏感株(MSSA和MSCNS),MRSA中有90.7%的菌株对复方磺胺甲噁唑敏感,MRCNS中有93.2%的菌株对阿米卡星敏感,未发现万古霉素和利奈唑胺耐药的菌株。青霉素耐药肺炎链球菌(PRSP)检出率为12.9%。结论 定期进行细菌耐药性监测有助于了解医院细菌耐药性变迁,为临床合理规范使用抗菌药物提供依据,指导院感管理防控措施的制定和避免耐药菌株的传播流行。     

Patterns of isolation of common gram positive bacterial pathogens and their susceptibilities to antimicrobial agents in Jimma Hospital

Gram positive bacteria are frequently emerging as antibiotic resistant pathogens, causing serious infections than ever before in the ill and debilitated patients. The pattern of isolation and the antimicrobial susceptibilities of common Gram positive cocci including Staphylococcus aureus, coagulase negative staphylococcus (CoNS), Streptococcus pyogenes, Enterococcus species and Streptococcus pneumoniae was investigated between January 1997 and June 2000 in Jimma Hospital. Of the 500 specimens collected from children and adults, 116 (23.2%) consisted of one or more of the above organisms. The following strains: Staphylococcus aureus, 47 (40.5%), CoNS, 36 (31.0%), Streptococcus pneumoniae, 26 (22.4%) Streptococcus pyogenes, 5 (4.3%) and Streptococcus faecalis, 2(1.7%) were isolated from different specimens including pus, sputum, urine, stool, blood and oro/nasopharyngeal swabs of patients. The in vitro activities of 14 different antibiotics including penicillin G, ampicillin, cloxacillin, cephalothin, gentamicin, kanamycin, tetracycline, chloramphenicol, erythromycin, trimethoprim-sulfamethoxazole, streptomycin, methicillin, vancomycin and clindamycin was determined against the clinical bacterial isolates. The antimicrobial activities were evaluated by agar diffusion technique using Mueller-Hinton agar according to NCCLS recommendations. The majority of the pathogens, 59(50.9%) were recovered from upper respiratory tract infections and 17 (14.6%) from the lower respiratory tract. The resistance patterns of S. aureus, CoNS, S. pneumoniae and enterococci to penicillin was 91.5%, 94.4%, 7.7% and 100% respectively. Penicillin, ampicillin and cloxacillin showed low effects (< 60%) on both S. aureus and CoNS. Multi-drug resistance was observed in all the gram-positive isolates, especially higher in staphylococcus species. All isolates of S. aureus (100%) were susceptible to vancomycin, clindamycin and gentamicin. In order to reduce morbidity and mortality due to antibiotic resistance susceptibility testing should be performed for the proper management of bacterial infections. This entails the need for national surveillance to monitor antibiotic resistance in bacteria by susceptibility testing using reliable methods.     

2018年内蒙古包头市细菌耐药性监测

目的 了解2018年内蒙古包头市11所参加全国细菌耐药监测网医院临床分离株的构成及耐药情况,为本地区临床合理化用药提供理论依据。方法 各成员医院按监测方案,采用纸片扩散法或自动化仪器检测法进行药敏试验,按美国临床实验室标准化研究协会(CLSI) 2017年版标准判读药敏结果,采用WHONET 5.6软件进行数据分析。结果 共收集上述医院非重复临床分离菌7773株,其中革兰阳性菌2138株,占27.5%,革兰阴性菌5635株,占72.5%。耐甲氧西林金黄色葡萄球菌(MRSA)和耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)的平均检出率分别为12.2%和66.9%,MRSA和MRCNS对大多数抗菌药物的耐药率均显著高于甲氧西林敏感株(MSSA和MSCNS),未发现利奈唑胺、万古霉素和替考拉宁耐药菌株。屎肠球菌对大多数抗菌药物的耐药率均显著高于粪肠球菌,粪肠球菌中发现有3株利奈唑胺、1株万古霉素和1株替考拉宁耐药菌株。非脑脊液标本分离的肺炎链球菌对青霉素的耐药率为2.0%。大肠埃希菌和克雷伯菌属中产ESBL菌株的平均检出率分别为48.3%和20.6%,产ESBL菌株对所测抗菌药物的耐药率均高于非产ESBL菌株。肠杆菌科细菌中CRE的检出率为1.2%,CRKP菌株对阿米卡星的耐药率为64.3%。铜绿假单胞菌对碳青霉烯类、氨基糖苷类、喹诺酮类、头孢他啶、头孢吡肟、头孢哌酮/舒巴坦和哌拉西林/三唑巴坦的耐药率均低于15.0%。不动杆菌属对包括碳青霉烯类在内的大多数抗菌药物的耐药率超过38.0%,其中亚胺培南和美罗培南的耐药率分别为42.3%和43.5%。结论 我市细菌耐药情况较全国水平低,但仍呈缓慢增长趋势,应继续做好细菌耐药性监测工作,加强抗菌药物临床应用管理措施,以合理化使用抗菌药物。     

2018年内蒙古包头市细菌耐药性监测

目的 了解2018年内蒙古包头市11所参加全国细菌耐药监测网医院临床分离株的构成及耐药情况,为本地区临床合理化用药提供理论依据。方法 各成员医院按监测方案,采用纸片扩散法或自动化仪器检测法进行药敏试验,按美国临床实验室标准化研究协会(CLSI) 2017年版标准判读药敏结果,采用WHONET 5.6软件进行数据分析。结果 共收集上述医院非重复临床分离菌7773株,其中革兰阳性菌2138株,占27.5%,革兰阴性菌5635株,占72.5%。耐甲氧西林金黄色葡萄球菌(MRSA)和耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)的平均检出率分别为12.2%和66.9%,MRSA和MRCNS对大多数抗菌药物的耐药率均显著高于甲氧西林敏感株(MSSA和MSCNS),未发现利奈唑胺、万古霉素和替考拉宁耐药菌株。屎肠球菌对大多数抗菌药物的耐药率均显著高于粪肠球菌,粪肠球菌中发现有3株利奈唑胺、1株万古霉素和1株替考拉宁耐药菌株。非脑脊液标本分离的肺炎链球菌对青霉素的耐药率为2.0%。大肠埃希菌和克雷伯菌属中产ESBL菌株的平均检出率分别为48.3%和20.6%,产ESBL菌株对所测抗菌药物的耐药率均高于非产ESBL菌株。肠杆菌科细菌中CRE的检出率为1.2%,CRKP菌株对阿米卡星的耐药率为64.3%。铜绿假单胞菌对碳青霉烯类、氨基糖苷类、喹诺酮类、头孢他啶、头孢吡肟、头孢哌酮/舒巴坦和哌拉西林/三唑巴坦的耐药率均低于15.0%。不动杆菌属对包括碳青霉烯类在内的大多数抗菌药物的耐药率超过38.0%,其中亚胺培南和美罗培南的耐药率分别为42.3%和43.5%。结论     

Fluoroquinolones: mechanisms of action and resistance

The mechanism of action and the mechanism of resistance of the 4-quinolones are complex and poorly understood. The first barrier these molecules must cross is the bacterial outer membrane. In gram-negative species, 4-quinolones pass through either the porins or lipopolysaccharides (or both) depending on their chemical nature. The cellular target is the DNA of the bacterial chromosome. 4-Quinolones mainly modify the activity of topoisomerase II or DNA gyrase, but also that of topoisomerase I and IV. Any damage to the bacterial genome will induce a stress response which consists in the SOS response, chaperonin synthesis or the generation of oxygen free radicals. Peptidoglycan synthesis is also modified, as shown by the inhibition of PBP(3) activity. Mechanism of resistance involves mutations on gyrA and gyrB genes. gyrA Mutations on the chromosome are responsible for a high level of resistance due to a modification of the A subunit of DNA gyrase, mutations on gyrB gene are responsible for a low level of resistance; the combination of both mutations leads to a high level of resistance. Other mutations are responsible for increasing the MIC, such as a norA mutation in S. aureus. The antibacterial activity of the various molecules is different and, as a result, there is not a single mechanism of action or resistance, but rather a common trunk on which additional mechanisms are grafted.     

重度脑外伤院内下呼吸道感染病原菌分布及其耐药性监测

目的探讨重度脑外伤院内下呼吸道感染细菌谱及耐药情况。方法 回顾1998年1月—2003年12月神经外科病房196例下呼吸道分泌物培养及药敏结果。结果 重度脑外伤患者院内下呼吸道感染常见病原菌为鲍曼不动杆菌(37．2％)、金黄色葡萄球菌(31．6％)、肺炎克雷伯菌(27．0％)、铜绿假单胞菌(25．5％)及真菌；其中鲍是不动杆菌、肺炎克雷伯菌及铜绿假单胞菌对亚胺培南西司他丁高度敏感，金黄色葡萄球菌对糖肽类万古霉素未发现耐药。结论 重度脑外伤患者误吸、长期使用广谱抗生素及大剂量使用激素是院内下呼吸道感染的主要原因。     

The use of beta-galactosidase gene fusions to screen for antibacterial antibiotics

The desirable features for a screening assay to detect antibacterial antibiotics include 1) high specificity for the desired antibiotic type 2) high sensitivity 3) lack of interference by other compounds likely to be associated with the antibiotic of interest and 4) ease of operation to allow a large number of samples to be tested. These characteristics are largely found in screens employing strains carrying fusions between antibiotic induced promoters and the structural genes for Escherichia coli beta-galactosidase. Screens were designed based upon fusions with three antibiotic induced promoters: the tetracycline induced tetA/tetR promoter from transposon Tn10, the erythromycin induced promoter from the Staphylococcus aureus ermC erythromycin-resistance gene and the chloramphenicol induced promoter from the S. aureus cat86 chloramphenicol-resistance gene. Because there have been no reports of vancomycin induced resistance determinants, a Tn903 random gene fusion pool was screened to isolate a vancomycin induced gene fusion. This gene fusion was induced fairly specifically by glycopeptide antibiotics and the fusion was used as the basis for a glycopeptide screen.     

新建医院金黄色葡萄球菌感染分布与耐药性分析

目的:探讨金黄色葡萄球菌感染分布及耐药特征,指导临床合理用药。方法:应用西门子公司MicroScan-40SI全自动细菌鉴定/药敏分析系统、K-B法药敏试验(美国BD)、β-内酰胺酶测试(OXOID),并以"WHONET5.3"软件对数据进行分析处理。结果:三年共检出病原菌2901株,金黄色葡萄球菌277株占(9.5%),其中产β-内酰胺酶86株,占31.0%,MRSA占SA感染标本总数的32.6%,MRSA耐药率介于2.4%-91.0%。本室三年来未检出耐万古霉素、替考拉宁、奎奴普丁/达福普汀、利奈唑胺菌株;耐药率低的抗生素有利福平、哌拉西林/他唑巴坦、阿莫西林/克拉维酸、复方磺胺甲口恶唑、头孢唑啉;耐药率高的有青霉素、氨苄西林、苯唑西林、红霉素等。结论:本组对新建民营医院三年金黄色葡萄球菌感染菌株的分布与耐药性进行统计分析,产β-内酰胺酶菌株比例较其他报告53.3%为低,头孢唑啉药物敏感性较稳定,但对其它β一内酰胺类抗菌药物耐药性高,并对β一内酰胺酶抑制剂耐药性出现逐年上升趋势,应引起关注。     

重症监护患者下呼吸道感染常见病原菌的耐药性分析

目的:调查我院重症监护患者下呼吸道感染常见病原菌的分布与耐药情况,为抗感染治疗提供依据。方法:对本院重症监护患者下呼吸道感染分离的312株致病菌用VITEK32全自动细菌鉴定及药敏系统进行细菌培养鉴定及药敏试验,部分药敏试验为K-B法。结果:感染革兰阴性杆菌62．8％。主要菌群有铜绿假单胞菌29．5％,鲍曼不动杆菌12．8％,肺炎克雷伯菌10．9％,大肠埃希菌5．8％,嗜麦芽窄食单胞菌5．1％等,革兰阳性球菌18．2％,真菌18．9％,头孢哌酮/舍巴坦和亚胺培南对革兰阴性杆菌搞菌活性较高,铜绿假单胞菌对头孢哌酮/舒巴坦敏感率较高,对亚胺培南的耐药率40．8％,革兰阳性球菌中金黄色葡萄球菌12．8％,耐苯唑西林金黄色葡萄球菌100％。肺炎克雷伯菌、大肠埃希菌ESBLs的检出率分别为39％、59％,真菌以白色念珠菌为主,对常用药物敏感性较高。结论:我院重症监护患者下呼吸道感染主要病原菌常为多重耐药的革兰氏阴性杆菌、MRSA,对常用抗菌药物耐药性较高,真菌所占比例也较高,加强细菌耐药性监测,合理使用抗生素对临床抗感染治疗十分重要。