2014~2019年郑州大学第一附属医院血培养分离病原菌临床分布及耐药性分析

目的　了解郑州大学第一附属医院血培养病原菌的构成及耐药性。方法　回顾性分析郑州大学第一附属医院 2014年 1月 ~2019年 12月间临床血培养分离的 13 456株细菌药敏结果,按照 CLSI2019年标准,使用 WHONET 5.6软件进行数据分析。结果　血培养分离前 5位的细菌分别为大肠埃希菌 3 121株（23.2%）、凝固酶阴性葡萄球菌 2 822株（21.0%）、肺炎克雷伯菌 2 038株（15.1%）、金黄色葡萄球菌 844株（6.3%）和屎肠球菌 727株（5.4%）。大肠埃希菌对亚胺培南、厄他培南的耐药率分别为 3.7%和 4.2%。肺炎克雷伯菌对亚胺培南、厄他培南的耐药率分别为 43.5%和 47.6%。鲍曼不动杆菌对大多数测试抗生素耐药性高,而铜绿假单胞菌对大多数抗生素保持较高的敏感性。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）的检出率分别为 42.1%和 84.2%,未发现万古霉素耐药的金黄色葡萄球菌。结论　郑州大学第一附属医院血培养分离细菌耐药情况较为严重,临床应合理应用抗生素,主动开展细菌耐药性监测,遏制细菌耐药性的上升。     

2005年广州医学院第一附属医院细菌耐药性监测

目的调查广州医学院第一附属医院2005年临床分离菌对各种抗菌药物的耐药现状。方法药敏试验采用纸片扩散法,数据分析采用WHONET5.4软件。结果2005年我院共收集患者首次分离株1843株,其中革兰阳性菌507株(27.51%),革兰阴性菌1336株((72.49%)。MRSA和MRCNS的检出率分别为71.7%和87.6%。粪肠球菌对呋喃妥因、氨苄西林的敏感率分别为88.0%和73%。未出现万古霉素和替考拉宁中介和耐药的葡萄球菌和肠球菌。肠杆菌科细菌对亚胺培南和美罗培南均极敏感,耐药率最低。大肠埃希菌和肺炎克雷伯菌中ESBLs的检出率分别为36.6%和56.1%。鲍曼不动杆菌对亚胺培南和美罗培南的敏感率分别为98.8%和90.2%。铜绿假单胞菌对亚胺培南和美罗培南的耐药率分别为48.0%和39.2%,14.0%菌株对所有检测药物耐药。结论我院2005年临床分离菌以革兰阴性菌为主,铜绿假单胞菌位居第一。肠杆菌科细菌对碳青霉烯类的敏感性最高,非发酵菌数量呈上升趋势,且耐药状况严重,14%铜绿假单胞菌对所有检测药物耐药。     

Antifungal susceptibilities of Aspergillus fumigatus clinical isolates obtained in Nagasaki, Japan

We investigated the triazole, amphotericin B, and micafungin susceptibilities of 196 A. fumigatus clinical isolates in Nagasaki, Japan. The percentages of non-wild-type (non-WT) isolates for which MICs of itraconazole, posaconazole, and voriconazole were above the ECV were 7.1%, 2.6%, and 4.1%, respectively. A G54 mutation in cyp51A was detected in 64.2% (9/14 isolates) and 100% (5/5 isolates) of non-WT isolates for itraconazole and posaconazole, respectively. Amphotericin B MICs of ≥2 μg/ml and micafungin minimum effective concentrations (MECs) of ≥16 μg/ml were recorded for two and one isolates, respectively.     

2006年上海地区细菌耐药性监测

目的了解上海地区2006年14所医院临床分离株的耐药情况。方法采用纸片扩散法(KB法)和CLSI2006年的判断标准对31316株临床分离株作药敏试验。结果31316株细菌中革兰阳性菌占36.4%,革兰阴性菌占63.6%。耐甲氧西林金葡菌(MRSA)和耐甲氧西林凝固酶阴性葡萄球菌(MRCNS)的检出率分别为64.6%和82.2%。未发现万古霉素中介株(VISA)或耐药株(VRSA)。青霉素敏感肺炎链球菌(PSSP)成人患者和儿童患者中的检出率分别为96.0%和13.0%,青霉素不敏感株(包括PISP和PRSP)的检出率儿童中分别为73.2%和13.8%,成人中分别为4%和0。发现3株万古霉素耐药屎肠球菌。在大肠埃希菌、克雷伯菌属和奇异变形杆菌中产ESBLs菌的检出率分别为53.0%、51.1%和19.5%。铜绿假单胞菌对亚胺培南和美罗培南的耐药率为24.4%和15.5%。不动杆菌属对亚胺培南和美罗培南的耐药率为15.5%和17.0%。出现少数铜绿假单胞菌(2.7%)、鲍曼不动杆菌(3.4%)和弗劳地柠檬酸杆菌(7.2%)的泛耐药株。结论细菌耐药性持续增加,出现泛耐药的铜绿假单胞菌、鲍曼不动杆菌和弗劳地柠檬酸杆菌,加强细菌耐药性监测,对于正确合理选用抗菌药和控制细菌耐药性产生十分重要。     

Susceptibilities of Eikenella corrodens, Prevotella intermedia, and Prevotella nigrescens clinical isolates to amoxicillin and tetracycline

The AB Biodisk Etest showed that 106 (100%) and 98 (92%) isolates of Eikenella corrodens were susceptible to amoxicillin and tetracycline, respectively. Twenty-three (68%) Prevotella intermedia isolates and 14 (67%) Prevotella nigrescens isolates were susceptible to amoxicillin. Seventy-nine percent of the P. intermedia isolates and 67% of the P. nigrescens isolates were susceptible to tetracycline. A higher percentage of beta-lactamase-producing isolates of P. intermedia and P. nigrescens were identified with selective agar containing amoxicillin than with nonselective agar.     

High prevalence of antimicrobial resistance among Shigella isolates in the United States tested by the National Antimicrobial Resistance Monitoring System from 1999 to 2002

Shigella spp. infect approximately 450,000 persons annually in the United States, resulting in over 6,000 hospitalizations. Since 1999, the National Antimicrobial Resistance Monitoring System (NARMS) for Enteric Bacteria has tested every 10th Shigella isolate from 16 state or local public health laboratories for susceptibility to 15 antimicrobial agents. From 1999 to 2002, NARMS tested 1,604 isolates. Among 1,598 isolates identified to species level, 1,278 (80%) were Shigella sonnei, 295 (18%) were Shigella flexneri, 18 (1%) were Shigella boydii, and 7 (0.4%) were Shigella dysenteriae. Overall, 1,251 (78%) were resistant to ampicillin and 744 (46%) were resistant to trimethoprim-sulfamethoxazole (TMP-SMX). Prevalence of TMP-SMX- or ampicillin- and TMP-SMX-resistant Shigella sonnei isolates varied by geographic region, with lower rates in the South and Midwest regions (TMP-SMX resistance, 27% and 30%, respectively; ampicillin and TMP-SMX resistance, 25% and 22%, respectively) and higher rates in the East and West regions (TMP-SMX resistance, 66% and 80%, respectively; ampicillin and TMP-SMX resistance, 54% and 65%, respectively). Nineteen isolates (1%) were resistant to nalidixic acid (1% of S. sonnei and 2% of S. flexneri isolates); 12 (63%) of these isolates had decreased susceptibility to ciprofloxacin. One S. flexneri isolate was resistant to ciprofloxacin. All isolates were susceptible to ceftriaxone. Since 1986, resistance to ampicillin and TMP-SMX has dramatically increased. Shigella isolates in the United States remain susceptible to ciprofloxacin and ceftriaxone.     

Multicentre surveillance of antimicrobial resistance in enterococci and staphylococci from Colombian hospitals, 2001-2002

Invasive isolates of staphylococci and enterococci were collected from 15 tertiary care centres in five Colombian cities from 2001 to 2002. A total of 597 isolates were available for analysis. Identification was confirmed by both automated methods and multiplex PCR assays in a central laboratory. Staphylococcus aureus and coagulase-negative staphylococci (CoNS) corresponded to 49.6% and 29.6% of isolates, respectively, and 20.8% were identified as enterococci. MICs of ampicillin, ciprofloxacin, chloramphenicol, erythromycin, gentamicin, linezolid, oxacillin, rifampicin, teicoplanin, tetracycline, trimethoprim/sulfamethoxazole (SXT) and vancomycin were determined using an agar dilution method as appropriate. Screening for vancomycin-resistant S. aureus was also carried out on brain-heart infusion agar plates supplemented with vancomycin. The presence of mecA and van genes was investigated in methicillin-resistant staphylococci and glycopeptide-resistant enterococci (GRE), respectively. All staphylococci were susceptible to vancomycin, teicoplanin and linezolid. No VISA isolates were found. In S. aureus and CoNS, the lowest rates of resistance were found for SXT (7.4%) and chloramphenicol (10.7%), respectively. Resistance to oxacillin in S. aureus and CoNS was 52% and 73%, respectively. The mecA gene was detected in 97.5% of methicillin-resistant S. aureus isolates. In enterococci, resistance to glycopeptides was 9.7%: vanA (58.3%) and vanB (41.7%) genes were found. Pulsed-field gel electrophoresis indicated that the GRE isolates were closely related. Rates of resistance to ampicillin, ciprofloxacin, chloramphenicol, rifampicin and high levels of gentamicin and streptomycin were 9.7%, 27.4%, 8.9%, 43%, 17% and 28.2%, respectively. All enterococci were susceptible to linezolid.     

耐红霉素葡萄球菌对克林霉素诱导型耐药的检测

目的了解本院临床分离的葡萄球菌对克林霉素诱导型耐药的发生率,帮助临床医师正确选择药物。方法采用K-B纸片琼脂扩散法检测葡萄球菌对红霉素和克林霉素的耐药性,按照CLSI/NCCLS推荐的D-试验方法检测克林霉素诱导型耐药。结果133株受试葡萄球菌对红霉素和克林霉素耐药菌株数分别为66株(占49.6%)和43株(占33.3%),66株耐红霉素葡萄球菌中有20株(其中金黄色葡萄球菌10株、表皮葡萄球菌9株、腐生葡萄球菌1株)为克林霉素诱导型耐药株,占红霉素耐药株的30.3%。在红霉素耐药金黄色葡萄球菌和凝固酶阴性葡萄球菌中,克林霉素诱导型耐药的检出率分别达38.5%和25.0%。对红霉素和克林霉素同时敏感或克林霉素耐药株中,未检到克林霉素诱导型耐药株。结论对红霉素耐药克林霉素敏感葡萄球菌应进行D试验,报告克林霉素诱导耐药性结果,以便临床正确选择药物。     

Susceptibilities to Telithromycin and Six Other Agents and Prevalence of Macrolide Resistance Due to L4 Ribosomal Protein Mutation among 992 Pneumococci from 10 Central and Eastern European Countries

The macrolide and levofloxacin susceptibilities of 992 isolates of Streptococcus pneumoniae from clinical specimens collected in 1999 and 2000 were determined in 10 centers in Central and Eastern European countries. The prevalences of penicillin G-intermediate (MICs, 0.125 to 1 microg/ml) and penicillin-resistant (MICs, < or =2 microg/ml) Streptococcus pneumoniae isolates were 14.3 and 16.6%, respectively. The MICs at which 50% of isolates are inhibited (MIC(50)s) and the MIC(90)s of telithromycin were 0.016 and 0.06 microg/ml, respectively; those of erythromycin were 0.06 and >64 microg/ml, respectively; those of azithromycin were 0.125 and >64 microg/ml, respectively; those of clarithromycin were 0.03 and >64 microg/ml, respectively; and those of clindamycin were 0.06 and >64 microg/ml, respectively. Erythromycin resistance was found in 180 S. pneumoniae isolates (18.1%); the highest prevalence of erythromycin-resistant S. pneumoniae was observed in Hungary (35.5%). Among erythromycin-resistant S. pneumoniae isolates, strains harboring erm(B) genes (125 strains [69.4%]) were found to be predominant over strains with mef(E) genes (25 strains [13.4%]), L4 protein mutations (28 strains [15.6%]), and erm(A) genes (2 strains [1.1%]). Similar pulsed-field gel electrophoresis patterns suggested that some strains containing L4 mutations from the Slovak Republic, Bulgaria, and Latvia were clonally related. Of nine strains highly resistant to levofloxacin (MICs, >8 microg/ml) six were isolated from Zagreb, Croatia. Telithromycin at < or =0.5 microg/ml was active against 99.8% of S. pneumoniae isolates tested and may be useful for the treatment of respiratory tract infections caused by macrolide-resistant S. pneumoniae isolates.     

2013-2015年某结核病专科医院常见病原菌分布及耐药监测分析

目的 对2013-2015年某结核病专科医院临床分离病原菌进行分析,了解病原菌分布特点及耐药性.方法 采用VITEK2-compact检测系统对分离的细菌进行鉴定和药敏实验.采用WHONET5.6软件对细菌鉴定及药敏实验结果进行分析.结果 共检出革兰阴性菌2 991株,占90.4%,革兰阳性菌317株,占9.6%.连续3年检出率居前三位的病原菌依次为肺炎克雷伯菌、铜绿假单胞菌、鲍曼不动杆菌.2013-2015年,产超广谱β内酰胺酶(ESBLs)大肠埃希菌检出率分别为40.4%、48.2%和38.3%,产ESBLs肺炎克雷伯菌检出率分别为16.9%、8.4%和11.6%.未检出亚安培南耐药大肠埃希菌.肺炎克雷伯菌对亚安培南的耐药率平均为1.6%.甲氧西林耐药金黄色葡萄球菌(MRSA)检出率分别为53.8%、54.3%、42.9%.甲氧西林耐药凝固酶阴性葡萄球菌(MRCNS)检出率分别为84.5%、82.7%、85.9%.未检出万古霉素、利奈唑胺、替加环素耐药葡萄球菌.肠球菌对庆大霉素、利奈唑胺、替加环素、万古霉素比较敏感.结论 碳青霉烯类抗菌药是抗肠杆菌科细菌最有效药物.万古霉素、利奈唑胺和替加环素是抗葡萄球菌较好的药物.肺炎克雷伯菌、鲍曼不动杆菌检出率逐年上升.需加强耐药监测以控制多药耐药菌的传播.     

Antimicrobial resistance of Shigella isolates causing traveler's diarrhea.

Shigella isolates were identified as a cause of traveler's diarrhea in 67 (10%) of 675 patients and were tested for resistance to seven antimicrobial agents in a comparative study with those causing nontraveler's diarrhea in Spain. Ampicillin and chloramphenicol resistance was more frequent in Shigella flexneri (60 and 46%, respectively) than in Shigella sonnei (32 and 18%, respectively) and in travel-related isolates (P < 0.05 and 0.04, respectively). Of S. sonnei isolates from patients with traveler's diarrhea, 73 and 54% showed tetracycline and trimethoprim-sulfamethoxazole resistance, respectively, compared with only 8% of isolates from patients without a history of travel to developing countries (P < 0.007 and P < 0.0002). Low-level resistance to cephalosporins was found, whereas quinolone-resistant strains were not detected among travel-related Shigella isolates. Thus, quinolones may be an effective alternative therapy for travel-related shigellosis.     

耐红霉素葡萄球菌对克林霉素诱导型耐药的检测

目的了解本院临床分离的葡萄球菌对克林霉素诱导型耐药的发生率，帮助临床医师正确选择药物。方法采用K-B纸片琼脂扩散法检测葡萄球菌对红霉素和克林霉素的耐药性，按照CLSI／NCCLS推荐的D-试验方法检测克林霉素诱导型耐药。结果133株受试葡萄球菌对红霉素和克林霉素耐药菌株数分别为66株（49．6％）和43株（33．3％），66株耐红霉素葡萄球菌中有20株（其中金黄色葡萄球菌10株、表皮葡萄球菌9株、腐生葡萄球菌1株）为克林霉素诱导型耐药株，占红霉素耐药株的30．3％。在红霉素耐药金黄色葡萄球菌和凝固酶阴性葡萄球菌中，克林霉素诱导型耐药的检出率分别达38．5％和25．0％。对红霉素和克林霉素同时敏感或克林霉素耐药株中，未检到克林霉素诱导型耐药株。结论对红霉素耐药而克林霉素敏感的葡萄球菌应进行D-试验，报道克林霉素诱导耐药性结果，以便临床正确选择药物。     

High rates of resistance to colistin and polymyxin B in subgroups of Acinetobacter baumannii isolates from Korea

OBJECTIVES: To investigate antimicrobial resistance in clinical isolates of Acinetobacter spp. from two Korean hospitals. METHODS: Two hundred and sixty-five isolates of Acinetobacter spp. from two Korean hospitals were collected and were identified to species level using partial rpoB gene sequences. Antimicrobial susceptibility testing was performed using a broth microdilution method. RESULTS: rpoB gene sequences indicated that 214 isolates (80.8%) were Acinetobacter baumannii, and allowed these to be classified into three subgroups (I, II and III); 142 isolates (53.6%) belonged to subgroup I, 54 (20.4%) to subgroup II and 18 (6.8%) to subgroup III. Forty-eight isolates (18.1%) and 74 isolates (27.9%) were resistant to polymyxin B and colistin, respectively. However, antimicrobial resistance rates varied markedly between subgroups. While A. baumannii subgroup I showed low resistance rates to polymyxin B and colistin (2.1% and 7.0%, respectively), subgroups II and III showed high resistance rates to these antibiotics (38.9% and 64.8% in subgroup II and 72.2% and 88.9%, in subgroup III, respectively). Multidrug resistance was also significantly more frequent in subgroup I (45.1%) than in subgroups II and III (13.0% and 16.7%, respectively). CONCLUSIONS: Our data indicate that subgroup identification of A. baumannii may aid selection of appropriate antimicrobial agents for the treatment of Acinetobacter infections.     

5504株临床分离细菌和念珠菌的分布及耐药性分析

目的了解本院临床分离细菌和念珠菌的分布特征和耐药谱,为合理使用抗生素提供依据。方法大多数分离细菌的鉴定和药敏试验利用BD Phoenix仪,少数利用手工鉴定和K-B法。念珠菌利用显色平板分离和鉴定,K-B法药敏。数据分析用WHONET5.4软件。结果5504株细菌念珠菌中前6位为铜绿假单胞菌12.0%、大肠埃希菌9.7%、白色念珠菌8.7%、金黄色葡萄球菌6.9%、肺炎克雷伯菌6.8%、表皮葡萄球菌6.5%。G-杆菌中耐药率较低的为美洛培南、头孢哌酮/舒巴坦、亚安培南、哌拉西林-他唑巴坦、头孢他啶、阿米卡星和头孢吡肟。大肠埃希菌和肺炎克雷伯菌产超广谱β-内酰胺酶(ESBLs)的检出率为44.6%和40.1%。G 球菌耐药率较低的为万古霉素、替考拉宁、呋喃妥因、阿米卡星、氯霉素和头孢哌酮/舒巴坦。金黄色葡萄球菌、表皮葡萄球菌、溶血葡萄球菌和腐生葡萄球菌甲氧西林耐药性分别为55.9%、43.8%、48.2%和41.7%。念珠菌对两性霉素B和制菌霉素的耐药率均低于1.1%。结论本院临床分离肠杆菌科产ESBLs水平、非发酵菌多重耐药率和葡萄球菌甲氧西林耐药率居高不下,应加强抗生素的合理使用。     

Antimicrobial resistance in Cairo,Egypt 1999-2000: a survey of five hospitals

Antimicrobial resistance among bacterial pathogens is a global problem, but in Egypt data are sparse. We reviewed the antimicrobial susceptibility patterns of bloodstream isolates of Gram-positive cocci and Gram-negative bacilli in five hospitals in Cairo, Egypt, from 1999 to 2000. In addition, susceptibilities of non-bloodstream isolates of Streptococcus pneumoniae and Enterococcus spp. were analysed. High rates of resistance were found in most of the bacteria studied. In the hospitals, a variety of methods were used for identification and susceptibility testing, but in the laboratories quality controlled strains were utilized routinely, to ensure accurate performance of the assays. Only 29% of Staphylococcus aureus isolates and 23% of coagulase-negative staphylococcal isolates were oxacillin susceptible. Both groups of staphylococci were also highly resistant to erythromycin, co-trimoxazole, clindamycin and doxycycline; all isolates were susceptible to vancomycin. Susceptibility of S. pneumoniae isolates to penicillin, ceftriaxone and fluoroquinolones was 63%, 84% and 82%, respectively. Vancomycin susceptibility of the enterococci was 96%; susceptibility to high-level gentamicin and streptomycin was 54% and 48%, respectively. Resistance to most relevant antimicrobials was commonplace among the Gram-negative bacilli; however, most remained susceptible to imipenem. The percentage of bloodstream isolates of Escherichia coli susceptible to common antimicrobial agents was as follows: ampicillin (6%), ampicillin-sulbactam (38%), co-trimoxazole (38%) and aminoglycosides (52%). The susceptibility of isolates of E. coli, Klebsiella and Enterobacter spp. to ceftazidime was 62%, 40% and 46%, respectively. This suggests a potentially high rate of extended-spectrum beta-lactamase (ESBL) and/or Amp-C enzyme production. These results call for a nationwide surveillance programme to monitor microbial trends and antimicrobial resistance patterns in Egypt.     

A comparison of the microbiological characteristics of Neisseria gonorrhoeae isolated from male and female patients with gonorrhea

BACKGROUND: A trend towards a decrease in gonorrhea in Japan was observed until the mid-1990s, but soon after that period, an increased incidence of gonorrhea was reported. METHODS: Antimicrobial susceptibility, auxotype and the type of gyrA and parC mutations were compared between 200 and 132 Neisseria gonorrhoeae isolates from male and female patients with gonorrhea, respectively. RESULTS AND CONCLUSION: The isolation frequency of ciprofloxacin-resistant isolates from male patients was higher than that from female patients (19.5 and 13.6%, respectively). All ciprofloxacin-resistant isolates had single to triple mutations in gyrA and/or parC genes. N. gonorrhoeae isolates showed a predominance of Pro-requiring auxotypes (46.5 and 46.2% of the isolates from male and female patients, respectively). Of the Pro-requiring isolates, the incidence of ciprofloxacin-resistant isolates was higher in the isolates from male patients than in the isolates from female patients.     

中国九家教学医院肠杆菌科细菌质粒介导的喹诺酮耐药机制研究

目的 研究质粒介导的喹喏酮类的耐药基因qnr和aac(6')-Ib-cr在我国肠杆菌科临床株中的分布状况.方法 从全国9家教学医院收集的421株非重复的4种肠杆菌科细菌[大肠埃希菌(eco)、肺炎克雷伯菌(kpm)、阴沟肠杆菌(ecl)、弗劳地柠檬酸杆菌(cfr)]中,按环丙沙星(CW)≥0.25μg/ml、头孢噻肟(CTX)≥2.0μg/ml、头孢曲松(cno)≥2.0μg/ml的条件筛选出197株,其中cfr30株,ecl 35株,eco 77株,kpm 55株.采用PCR检测筛选菌株的qnrA、qnrB、qnrS和aac(6')-IB质粒介导耐药基因;并以内切酶BtsCI酶切消化aac(6')-Ib PCR阳性产物以确定aac(6')-Ib-cr.接合试验确定喹诺酮耐药的可转移性;用琼脂稀释法测定接合子及其供体菌和受体菌对环丙沙星及其他抗菌药的MIC值.结果 在197株筛选出的肠杆菌科细菌中,qnr共检出83株,总阳性率为42%(83/197),其中qnrA有17株(9%),qnrB有46株(23%),qnrS有24株(12%);qnrA和qnrB同时阳性有2株,qnrB和qnrs同时阳性有2株.aac(6')-Ib共检出90株(46%),aac(6')-Ib-cr共检出36株(18%).qnr和aac(6')-Ib-cr同时阳性的有18株.在ecl、kpn、cfr、eco中,qnr的阳性率分别为66%、66%、63%、6%,aac(6')-Ib-cr阳性检出率分别为9%、22%、27%、17%.qnr和aac(6')-Ib-cr在所有的4种肠杆菌科细菌中的阳性率分别为20%(83/421)和9%(36/421).质粒接合试验获得了13株接合子,环丙沙星对接合子的MIC范围为0.125～1μg/ml,相差8倍;接合子与受体菌相比,CIP的耐药性提高了16～125倍,左氧氟沙星的耐药性提高了16～31倍.结论 在中国,qnr和aac(6')-Ib-cr相关的质粒介导喹诺酮类耐药性在肠杆菌科临床分离株中分布广泛;qnr和aac(6')-Ib-cr能介导喹诺酮低水平耐药,这可能是我国细菌对喹诺酮类耐药性上升迅速的重要原因.     

Comparison of the ASTA MicroIDSys and VITEK MS matrix-assisted laser desorption/ionization time-of-flight mass spectrometry systems for identification of clinical bacteria and yeasts

The ASTA MicroIDSys system (ASTA, Suwon, Korea) is a newly developed Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) system for identification of microorganisms. We compared the performance of the ASTA MicroIDSys system with that of the VITEK MS system (bioMérieux, Marcy l’Etoile, France) for identifying clinical microorganisms. A total 2055 isolates including 1910 bacteria and 145 yeasts were tested. Among them, the VITEK MS correctly identified 1999 (97.3%) isolates to species level and 26 (1.3%) to the genus level. The ASTA MicroIDSys correctly identified 1988 (96.7%) isolates to species level and 28 (1.4%) to the genus level. The VITEK MS and ASTA MicroIDSys misidentified one isolate and four (0.2%) isolates, respectively, and provided no identification for 29 (1.4%) and 35 (1.7%) isolates, respectively. The performance of the ASTA MicroIDSys was comparable to that of the VITEK MS for identification of clinically relevant bacterial and yeast isolates.     

Prevalence and characterization of extended-spectrum beta-lactamase-producing Enterobacteriaceae isolated in Korean hospitals

Prevalence and characteristics of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in Korean hospitals were assessed. A total of 1484 clinical Enterobacteriaceae isolates were collected from 8 tertiary-care hospitals in various regions of Korea over a 3-month period (June to August) in 2005. Among 546 Klebsiella pneumoniae isolates, 123 isolates (22.4%) showed ESBL-producing activity, and 47 (10.2%) of 460 isolates of Escherichia coli were ESBL producers. Of the Enterobacter cloacae isolates, 16.2% (17/105) evidenced ESBL-producing activity. The most prevalent ESBLs were SHV-12 and CTX-M-14 in K. pneumoniae and E. coli, respectively. In E. cloacae, SHV-12 was also the most prevalent. Prevalence of ESBL production differed among the specimens. Although the K. pneumoniae isolates from urine and aspirates evidenced high ESBL production rates (35.4% and 57.1%, respectively), those from sputum, blood, and pus showed relatively low ESBL production rates (17.0%, 14.8%, and 5.3%, respectively). However, E. coli isolates obtained from sputum showed significantly higher ESBL production rates (37.5%) than were seen in samples obtained from other sources, but those obtained from urine showed lower ESBL production rates (8.3%). These significant differences in ESBL-producing K. pneumoniae and E. coli isolates among the isolated specimens should be examined further, with an eye toward the implications of this research in clinical settings.     

Phenotypic and genotypic aminoglycoside resistance in blood culture isolates of coagulase-negative staphylococci from a single neonatal intensive care unit, 1989-2000

OBJECTIVES: To investigate the prevalence of aminoglycoside resistance and genes encoding aminoglycoside-modifying enzymes (AME) in blood culture isolates of coagulase-negative staphylococci (CoNS) from neonates. MATERIALS AND METHODS: A total of 180 isolates from 148 patients collected in a single neonatal unit over a 12 year period were examined for susceptibility to gentamicin, tobramycin, netilmicin, amikacin and arbekacin by Etest and/or disc diffusion. AME genes were detected by PCR. RESULTS: The overall non-susceptibility rates to gentamicin, tobramycin, netilmicin, amikacin and arbekacin were 66%, 68%, 52%, 38% and 1%, respectively. Gentamicin non-susceptibility rates were 4% and 91% in methicillin-susceptible and -resistant isolates, respectively. aac(6')-Ie-aph(2')-Ia, aph(3')-IIIa and/or ant(4')-Ia were encountered in 125 (69%), 1 (0.5%) and 30 (16.6%) isolates, respectively. Forty-six (26%) isolates negative for AME genes were susceptible to all aminoglycosides. In contrast, 115 (92%), 91 (73%) and 66 (53%) of aac(6')-Ie-aph(2')-Ia positive isolates were non-susceptible to gentamicin, netilmicin and amikacin, respectively. Only one isolate showed arbekacin resistance. However, aac(6')-Ie-aph(2')-Ia positive isolates and isolates with gentamicin MIC > or =128 mg/L displayed a significant reduction in arbekacin inhibition zones. CONCLUSIONS: A high prevalence of aminoglycoside resistance was detected and associated with methicillin resistance. Discrepancies between phenotypic and genetic detection of aminoglycoside resistance were discerned. Gentamicin was the preferred substrate for phenotypic detection of aac(6')-Ie-aph(2')-Ia. Arbekacin showed favourable antibacterial activity even in aac(6')-Ie-aph(2')-Ia-positive isolates. We suggest including arbekacin in future clinical trials of empirical treatment of late onset neonatal sepsis.