嗜麦芽窄食单胞菌耐药现状及分子流行病学特征

目的了解嗜麦芽窄食单胞菌耐药现状及分子流行病学特征。方法临床分离嗜麦芽窄食单胞菌30株,经VITEK微生物鉴定系统重新鉴定。微量肉汤稀释法检测14种抗菌药物的MIC、肠杆菌科基因间重复-致序列[(ERIC)-PCR]方法分析嗜麦芽窄食单胞菌流行特征。结果30株嗜麦芽窄食单胞菌对亚胺培南、美罗培南、头孢噻肟、氨曲南和阿米卡星高度耐药;但对头孢哌酮-舒巴坦、哌拉西林-三唑巴坦、复方磺胺甲噁唑和替卡西林-克拉维酸仍保持一定敏感性,敏感率分别为96.7%、76.7%、73.3%和60%。ERIC-PCR指纹图谱显示30株嗜麦芽窄食单胞菌由26种不同克隆构成。结论嗜麦芽窄食单胞菌对常用抗菌药物呈多重耐药,但对头孢哌酮-舒巴坦、哌拉西林-三唑巴坦、复方磺胺甲噁唑、替卡西林-克拉维酸仍保持一定敏感性。30株嗜麦芽窄食单胞菌分子流行病学显示基因型多态性。     

嗜麦芽窄食单胞菌呼吸道感染的临床及药敏分析

目的：探讨嗜麦芽窄食单胞菌呼吸道感染的危险因素及耐药情况。方法：收集经痰或呼吸道吸出物培养分离出的38株嗜麦芽窄食单胞菌的药敏试验结果，复习有关临床资料，分析发病的危险因素。结果：对18例抗菌药物敏感率依次为复方磺胺甲恶唑（78．6％），替卡西林－克拉维酸（66．7％），头孢他啶（48．2％），哌拉西林－三唑巴坦（42．8％），环丙沙星（42．1％），头孢哌酮－舒巴坦（41．3％），有12种抗生素的耐药率＞60％（66．7％）。结论：嗜麦芽窄食单胞菌已成为呼吸道医院感染的致病原菌之一，多发生在免疫力低下的老年，慢性，长期接受抗菌药物治疗的病人，重危监护病房的病人也是感染的高危人群。一旦造成感染，可选用抗菌药物的范围较窄，治疗相对困难。     

E试验检测42株嗜麦芽窄食单胞菌对5种抗菌药物的敏感性

目的：检测嗜麦芽窄食单胞菌对5种抗菌药物的敏感性并探讨体外试验如何更准确检测该菌耐药性。方法：用E试验检测42株临床分离菌株对替卡西林-克拉维酸、哌拉西林-三唑巴坦、头孢哌酮-舒巴坦、环丙沙星和复方磺胺甲噁唑的敏感性，分别于培养24h和48h记录结果。结果：无论培养24h还是48h。5种抗菌药物的敏感性由高到低依次为复方磺胺甲噁唑、头孢哌酮-舒巴坦、替卡西林-克拉维酸、环丙沙星和哌拉西林-三唑巴坦。药敏试验延长至48h判读结果，部分在24h敏感的菌株抑菌区内可见小的耐药菌生长。结论：嗜麦芽窄食单胞菌对所试5种抗菌药物均有不同程度耐药性，治疗时应采用联合用药。延长药敏培养时间可检出更多生长缓慢的耐药菌株。     

嗜麦芽窄食单胞菌体外药敏试验方法研究

目的：比较纸片扩散法和琼脂稀释法作嗜麦芽窄度食单胞菌的药敏试验。方法：采用琼脂稀释法和纸片扩散法，测定嗜麦芽窄食单胞菌对14种抗菌药物的敏感度。结果：琼脂稀释法测得嗜麦芽窄食单胞菌对头孢哌酮和头孢哌酮一舒巴坦复方制剂敏感率最高，分别为92．2％和95％；其次为复方磺胺甲噁唑、替卡西林一克拉维酸、环丙沙星和哌拉西林一三唑巴坦，细菌敏感率分别为84．3％、87．3％、76．5％和75．5％。对大多数抗菌药物的敏感率琼脂稀释法较纸片扩散法高，其差异有显著性。结论：临床微生物实验室应以稀释法进行嗜麦芽窄食单胞菌的药物敏感性试验。     

3种常见非发酵革兰阴性杆菌的体外药物敏感性

目的比较米诺环素、亚胺培南、头孢哌酮-舒巴坦、左氧氟沙星、莫西沙星、复方磺胺甲噁唑、替卡西林-克拉维酸、头孢他啶和美罗培南等药物对鲍曼不动杆菌、嗜麦芽窄食单胞菌和洋葱伯克霍尔德菌的体外抗菌活性。方法采用琼脂稀释法测定各种抗菌药物对测试菌株的MIC,用WHONET5.3软件分析药敏结果。结果鲍曼不动杆菌对测试药物的敏感率依次为亚胺培南(75.4%)、米诺环素(69.3%)、头孢哌酮-舒巴坦(51.8%);嗜麦芽窄食单胞菌对测试药物的敏感率依次为米诺环素(87%)、莫西沙星(86.1%)、左氧氟沙星(82.4%)、复方磺胺甲噁唑(75%);洋葱伯克霍尔德菌对测试药物的敏感率依次为米诺环素(77.2%)、美罗培南(61.4%)、头孢他啶(56.1%)。结论米诺环素对鲍曼不动杆菌、嗜麦芽窄食单胞菌和洋葱伯克霍尔德菌均有较高的抗菌活性,值得进一步临床研究。     

嗜麦芽窄食单胞菌体外药敏试验方法评价及耐药性分析

目的评价纸片扩散法和仪器法检测嗜麦芽窄食单胞菌药敏试验的可靠性,分析嗜麦芽窄食单胞菌对常用抗菌药物的敏感性。方法琼脂稀释法、VITEK-AMS和纸片扩散法检测嗜麦芽窄食单胞菌对11种抗菌药物的敏感性。结果纸片法与琼脂稀释法检测嗜麦芽窄食单胞菌对哌拉西林-他唑巴坦的药敏结果差异有显著性;VITEK-AMS和琼脂稀释法检测嗜麦芽窄食单胞菌对阿莫西林-克拉维酸、哌拉西林-他唑巴坦、头孢他啶、复方磺胺甲王月唑的药敏结果差异有显著性;嗜麦芽窄食单胞菌对氧氟沙星、复方磺胺甲王月唑的敏感性较高。结论纸片法和VITEK-AMS用于嗜麦芽窄食单胞菌的药物敏感性检测存在缺陷;治疗嗜麦芽窄食单胞菌引起的感染可选用左氧氟沙星、复方磺胺甲王月唑。     

嗜麦芽窄食单胞菌体外药敏试验方法评价及耐药性分析

目的评价纸片扩散法和仪器法检测嗜麦芽窄食单胞菌药敏试验的可靠性，分析嗜麦芽窄食单胞菌对常用抗菌药物的敏感性。方法琼脂稀释法、VITEK—AMS和纸片扩散法检测嗜麦芽窄食单胞菌对11种抗菌药物的敏感性。结果纸片法与琼脂稀释法检测嗜麦芽窄食单胞菌对哌拉西林-他唑巴坦的药敏结果差异有显著性；VITEK—AMS和琼脂稀释法检测嗜麦芽窄食单胞菌对阿莫西林-克拉维酸、哌拉西林-他唑巴坦、头孢他啶、复方磺胺甲唾唑的药敏结果差异有显著性；嗜麦芽窄食单胞菌对氧氟沙星、复方磺胺甲唾唑的敏感性较高。结论纸片法和VITEK—AMS用于嗜麦芽窄食单胞菌的药物敏感性检测存在缺陷；治疗嗜麦芽窄食单胞菌引起的感染可选用左氧氟沙星、复方磺胺甲噁唑。     

重症监护病房革兰阴性杆菌耐药性监测与分析

目的了解重症监护病房（ICU）革兰阴性杆菌对临床常用抗菌药的耐药性变化，以指导合理选择抗菌药物。方法采用纸片扩散法对2003年1月-2004年12月我院ICU分离出的革兰阴性杆菌进行药敏检测，按NCCLS2003年版标准判断结果。结果2年中分离出245株革兰阴性杆菌，其中以不动杆菌（48．2％）和铜绿假单胞（11．0％）为主的非发酵菌占65．3％，74．5％来自痰液标本。亚胺培南的总敏感率最高（93．9％），对除嗜麦芽窄食单胞菌外的其他革兰阴性杆菌具有很好的抗菌活性；革兰阴性杆菌对头孢他啶、头孢哌酮-舒巴坦、头孢吡肟、哌拉西林-三唑巴坦和阿米卡星的敏感率多数为44％～68％，对其他抗菌药高度耐药；头孢他啶和复方磺胺甲嘿唑对嗜麦芽窄食单胞菌的敏感率高达73．3％。大肠埃希菌和肺炎克雷伯菌产ESBLs菌株分别占26．3％和32．3％；产酶菌株对多数常用抗菌药物耐药率高于非产酶菌株，对亚胺培南无耐药，头孢哌酮-舒巴坦和哌拉西林-三唑巴坦对产ESBLs菌株抗菌活性明显强于其他头孢菌素。结论非发酵菌在从ICU分离出的革兰阴性杆菌中占有较高比例，亚胺培南对除嗜麦芽窄食单胞菌外的其他革兰阴性杆菌具有较好的抗菌活性，其他抗菌药物抗菌活性较低。     

嗜麦芽窄食单胞菌对8种氟喹诺酮类抗生素的交叉耐药性及耐药现状的探讨

目的观察嗜麦芽窄食单胞菌对8种氟喹诺酮类抗生素的交叉耐药性及其它各种抗生素耐药现状，以指导临床合理用药。方法采用纸片扩散法测定临床标本中分离的79株嗜麦芽窄食单胞菌对各种抗生素的体外抗菌活性。并比较了8种氟喹诺酮类药物的敏感性，同时比较分析环丙沙星与复方新诺明的体外抗菌活性。结果嗜麦芽窄食单胞菌对大多数β-内酰胺类抗生素耐药，对青霉紊类、头孢他啶、头孢噻肟、头孢吡肟、氨曲南高度耐药，对亚胺培南100％耐药，含酶抑制剂的β-内酰胺类复合制剂如头孢哌酮／舒巴坦、哌拉西林／他唑巴坦敏感率较单用相应β-内酰胺类抗生素有所提高（P〈0．05），阿莫西林／克拉维酸则无显著性变化；氨基糖苷类抗生索庆大霉素和阿米卡星也呈现高耐药性；氟喹诺酮类抗生素包括加替沙星、左氧氟沙星、氧氟沙星、依诺沙星、洛美沙星、环丙沙星、氟罗沙星敏感率最高；复方新诺明的体外抗菌活性低于氟喹诺酮类（诺氟沙星除外，P〈0．05）。结论嗜麦芽窄食单胞菌感染治疗首选氟喹诺酮类抗生素和复方新诺明，严重感染可选用昏内酰胺／酶抑制剂复合制剂与氟喹诺酮类联合用药。     

嗜麦芽窄食单胞菌135株分布及耐药性分析

目的 了解嗜麦芽窄食单胞菌的临床分布和耐药性情况,指导临床合理选用抗生素.方法 回顾性分析2008-2010年从南京鼓楼医院集团宿迁市人民医院住院患者分离的嗜麦芽窄食单胞菌的分布和药敏结果.结果 2008-2010年分离的嗜麦芽窄食单胞菌共135株,对于临床常用的抗生素敏感性从高到低依次为:米诺环素90.4%、左氧氟沙星74.1%、复方磺胺甲恶唑71.1%、头孢哌酮/舒巴坦49.6%、头孢他啶45.2%、替卡西林/克拉维酸35.6%、哌拉西林/他唑巴坦16.3%、头孢吡肟13.3%、阿米卡星12.6%、哌拉西林3.7%,所有菌株对亚胺培南和氨曲南均耐药.结论 嗜麦芽寡养单胞菌感染部位以呼吸道为主,其对大多数抗菌药物敏感度不高,临床治疗应依据药敏结果,合理选用抗生素,减少耐药菌株的产生.     

Antimicrobial Activities of Gatifloxacin against Nosocomial Isolates of Stenotrophomonas maltophilia Measured by MIC and Time-Kill Studies

We determined in vitro activities of gatifloxacin and seven other drugs against 100 isolates of Stenotrophomonas maltophilia using the agar gradient diffusion (Etest) method. Percentages of susceptible isolates were as follows: trimethoprim-sulfamethoxazole, 90%; gatifloxacin, 71%; levofloxacin, 57%; ticarcillin-clavulanic acid, 54%; ceftazidime, 49%; ciprofloxacin, 29%; cefepime, 21%; and piperacillin-tazobactam, 20%. Time-kill studies of three isolates indicated that gatifloxacin was bactericidal at times as early as 3 h of incubation when tested at concentrations equivalent to twice the MIC (two isolates) and 4 times the MIC (one isolate).     

2005年武汉同济医院细菌耐药性监测

目的了解2005年华中科技大学同济医学院附属同济医院临床分离常见病原菌对常用抗菌药物耐药情况。方法采用纸片扩散法进行抗菌药物敏感性试验,以WHONET5.3软件分析数据。结果3119株临床分离病原菌中,前6位病原菌依次为大肠埃希菌、铜绿假单胞菌、凝固酶阴性葡萄球菌、克雷伯菌属、不动杆菌属和金葡菌。嗜麦芽窄食单胞菌居第10位。耐甲氧西林金葡菌、耐甲氧西林凝固酶阴性葡萄球菌检出率分别为53.7%、74.8%。未检出糖肽类耐药革兰阳性球菌。肠杆菌科细菌对碳青霉烯类、头孢哌酮-舒巴坦、哌拉西林-三唑巴坦、阿米卡星耐药率<30%;不发酵糖革兰阴性杆菌对碳青霉烯类、头孢哌酮-舒巴坦耐药率亦低于30%。产ESBLs大肠埃希菌和克雷伯菌属检出率分别为58.2%和44.4%。铜绿假单胞菌对头孢他啶、头孢吡肟及环丙沙星耐药率为26.6%～28.6%。嗜麦芽窄食单胞菌对替卡西林-克拉维酸、氟喹诺酮类、米诺环素耐药率较低。结论临床常见病原菌中革兰阴性杆菌约占2/3,碳青霉烯类对其抗菌活性最强。临床细菌对多数常用抗菌药物耐药率呈上升趋势。     

In-vitro activity of cefepime and other broad-spectrum antimicrobials against several groups of gram-negative bacilli and Staphylococcus aureus

The in vitro activity of cefepime was compared with that of amikacin, ceftazidime, imipenem, ciprofloxacin, and piperacillin-tazobactam by using the E-test against five groups of carefully selected organisms: Klebsiella pneumoniae (68 isololates), Pseudomonas aeruginosa (62), methicillin-susceptible Staphylococcus aureus (MSSA) (60), and two groups of Enterobacteriaceae (60 and 62 isolates, respectively). The bacteria were subdivided according to whether the infection was nosocomial or community-acquired, applying accepted and predefined criteria. These isolates were obtained from patients admitted to our medical center throughout 1998. We retrospectively compared antimicrobial susceptibilities of the study sample with those of the +/- 3000 bacterial strains isolated from blood stream infections since 1990: the study sample appeared to represent adequately the clinical databank. Presence of extended-spectrum beta-lactamase (ESBL) was determined in all groups of Enterobacteriaceae with the ESBL screening E-test strip. Of the 252 Gram-negative bacilli tested, 242 (96%) were susceptible to cefepime, whereas only 168 (67%) were susceptible to ceftazidime, 211 (84%) to amikacin, and 220 (87%) to piperacillin-tazobactam (p < 0.001). Imipenem was slightly superior to cefepime with only seven isolates resistant (3%), six of which were P. aeruginosa. Cefepime was more active against Enterobacteriaceae than ceftazidime (93% vs. 72%, p < 0.001). This superiority was most evident against nosocomial strains of K. pneumoniae, against which cefepime was > three times more active than ceftazidime. The high level of resistance seen in nosocomial isolates of K. pneumoniae is consistent with high rates of ESBL production (69%, compared with 15-26% in other Enterobacteriaceae). The MIC90 of cefepime to methicillin-sensitive S. aureus was 1.5 micrograms/mL, whereas that of ceftazidime was 4 micrograms/mL; the susceptibility rate of both was 100%. In conclusion, cefepime possesses in vitro potencies against MSSA and current clinical strains of Gram-negative bacilli, many of which harbor resistance to other antimicrobial agents. Hence, it seems very suitable for empiric coverage of serious nosocomial infections.     

In vitro activities of moxifloxacin against 900 aerobic and anaerobic surgical isolates from patients with intra-abdominal and diabetic foot infections

The in vitro activities of moxifloxacin, ciprofloxacin, levofloxacin, gatifloxacin, imipenem, piperacillin-tazobactam, clindamycin, and metronidazole against 900 surgical isolates were determined using NCCLS testing methods. Moxifloxacin exhibited good to excellent antimicrobial activity against most aerobic (90.8%) and anaerobic (97.1%) microorganisms, suggesting that it may be effective for the treatment of polymicrobial surgical infections.     

Synergic activity of cephalosporins plus fluoroquinolones against Pseudomonas aeruginosa with resistance to one or both drugs

Owing to increasing resistance in Pseudomonas aeruginosa, empirical drug regimens may include agents to which some strains may be resistant. The purpose of this study was to evaluate the in vitro activities of different combinations of cephalosporin plus fluoroquinolone against P. aeruginosa isolates with varying susceptibility to the study drugs. Broth microdilution susceptibility testing was performed with 10 clinical isolates of P. aeruginosa. The bactericidal activity of cefepime or ceftazidime alone and in combination with ciprofloxacin, levofloxacin, gatifloxacin or moxifloxacin was evaluated using time-kill methods. Colony counts were determined at 0, 4, 8 and 24 h, using antimicrobial concentrations of 0.5 x MIC. All procedures were performed in duplicate. Synergy was defined as a >2-log decrease in cfu/mL at 24 h compared with the single most active agent. The MICs for tested strains were: ceftazidime 0.75-32, cefepime 0.125-8, ciprofloxacin 0.0078-8, levofloxacin 0.023-16, gatifloxacin 0.023-16 and moxifloxacin 0.0521-32 mg/L. Four strains were susceptible to all drugs, two strains were cephalosporin susceptible and fluoroquinolone resistant, and two strains were cephalosporin resistant and fluoroquinolone susceptible. Two strains were resistant or intermediately susceptible to all drugs. Various cephalosporin and fluoroquinolone combinations were synergic against P. aeruginosa, including strains resistant to one or both agents in combination. No synergy was observed in two strains susceptible to all drugs. There were no differences noted between different cephalosporin and fluoroquinolone combinations. Concentrations used in this study are clinically achievable with recommended regimens in most cases.     

Antimicrobial susceptibility and synergy studies of Stenotrophomonas maltophilia isolates from patients with cystic fibrosis

Stenotrophomonas maltophilia is a newly emerging pathogen being detected with increasing frequency in patients with cystic fibrosis (CF). The impact of this multidrug-resistant organism on lung function is uncertain. The optimal treatment for S. maltophilia in CF patients is unknown. We studied the in vitro activity of ten antimicrobial agents, and conducted synergy studies by using checkerboard dilutions of eight pairs of antimicrobial agents against strains isolated from 673 CF patients from 1996 to 2001. This represents approximately 7 to 23% of the CF patients in the United States who harbor S. maltophilia annually. Doxycycline was the most active agent and inhibited 80% of 673 initial patient isolates, while trimethoprim-sulfamethoxazole inhibited only 16%. High concentrations of colistin proved more active than high concentrations of tobramycin and gentamicin. Serial isolates (n = 151) from individual patients over time (median, 290 days) showed minimal changes in resistance. Synergistic or additive activity was demonstrated by trimethoprim-sulfamethoxazole paired with ticarcillin-clavulanate (65% of strains), ciprofloxacin paired with ticarcillin-clavulanate (64% of strains), ciprofloxacin paired with piperacillin-tazobactam (59% of strains), trimethoprim-sulfamethoxazole paired with piperacillin-tazobactam (55% of strains), and doxycycline paired with ticarcillin-clavulanate (49% of strains). In all, 522 (78%) isolates were multidrug resistant (i.e., resistant to all agents in two or more antimicrobial classes) but 473 (91%) of these were inhibited by at least one antimicrobial combination (median, four; range, one to eight). To determine appropriate treatment for patients with CF, it is important to monitor the prevalence, antimicrobial susceptibility, and clinical impact of S. maltophilia in this patient population.     

Global patterns of susceptibility for 21 commonly utilized antimicrobial agents tested against 48,440 Enterobacteriaceae in the SENTRY Antimicrobial Surveillance Program (1997-2001)

A total of 48,440 Enterobacteriaceae isolates collected consecutively from patients hospitalized in participant SENTRY Antimicrobial Surveillance Program sites in four international regions (Asia-Pacific, Europe, Latin America, and North America) were tested by reference broth microdilution method against the most commonly used antimicrobial agents. The most active compounds could be divided in 3 groups based on their spectrum of activity. The first group included meropenem and imipenem, with 99.9% susceptibilty (S) rates for the Enterobacteriaceae. The second group includes amikacin (97.3% S) and cefepime (97.2% S); and a third active group had a rank order of susceptibility of: gatifloxacin = levofloxacin (91.7% S) > ceftazidime (91.4% S) > ceftriaxone (91.2% S) > aztreonam (91.1% S) > gentamicin (90.6% S) > piperacillin/tazobactam = ciprofloxacin (90.5% susceptibility). These latter antimicrobial agents presented susceptibility rates of approximately 90% (89.8%-91.7%). Continued resistance surveillance by various programs remain necessary to monitor the in vitro effectiveness of antimicrobial agents currently used in clinical practice.     

Contemporary in vitro synergy rates for aztreonam combined with newer fluoroquinolones and beta-lactams tested against gram-negative bacilli

Aztreonam has been commonly used in various combinations to enhance antimicrobial spectrum of co-drugs and produce potential synergistic activity. Although well studied in vitro over 10 years ago, aztreonam combination testing has been poorly documented with newer or commonly used agents against contemporary isolates. All MIC tests (alone or in combination) used in this experiment were reference broth microdilution methods in checkerboard tray designs. Aztreonam was combined with ciprofloxacin, gatifloxacin, levofloxacin, cefepime, ceftazidime and imipenem at clinically relevant concentrations. Interaction categories were defined by established criteria. Forty strains each of Pseudomonas aeruginosa and Enterobacteriaceae (12 species; aztreonam MIC, 1-16 microg/ml) were tested for each antimicrobial combination (480 total determinations). No antagonism or indeterminate interactions were identified. The overall rates of synergy or partial synergy for aztreonam with fluoroquinolone combinations was 63.4% versus P. aeruginosa, greatest for aztreonam with gatifloxacin (67.5%). Interaction categories varied greatly among aztreonam with beta-lactam combinations. Aztreonam with ceftazidime or cefepime versus P. aeruginosa had 75.0 - 85.0% partial or complete synergy rates, but aztreonam with imipenem showed dominant indifference (65.0%). In contrast, aztreonam with imipenem was more likely to exhibit synergy (32.5%) when tested against Enterobacteriaceae. Aztreonam, often used as an aminoglycoside substitute in antimicrobial combinations, continues to demonstrate enhanced, but variable drug activity interactions for contemporary antimicrobial combinations when tested against recent (2002) clinical isolates.