心内科患者多药耐药铜绿假单胞菌医院感染危险因素的分析

目的 调查心内科住院患者多药耐药铜绿假单胞菌(MDRPA)的感染现状及医院感染的危险因素,为监测与控制心内科MDRpA感染提供依据.方法 收集心内科2007-2010年分离医院感染的MDRPA,采用Microscan Walk away 96SI全自动微生物鉴定仪鉴定并检测药物敏感性,将检测出的MDRP与同时期敏感铜绿假单胞菌作为对照,采用病例对照研究方法,单因素(t检验、x2检验)及多因素logistic回归进行分析.结果 连续收集到医院感染铜绿假单胞菌(PAE)80株,其中,MDRPA 25株,总分离率31.3％;主要标本来源是呼吸道标本,占77.5％;单因素分析发现,曾入住ICU、基础疾病、住院时间、纤维支气管镜灌洗、机械通气时间、分离出MDRPA前＜14 d使用碳青霉烯类抗菌药物与MDRP感染有关;多因素logistic回归分析确定了3项独立危险因素;曾入住ICU、机械通气、分离出MDRP前＜14 d用过碳青霉烯类抗菌药物.结论 曾入住ICU、机械通气以及碳青霉烯类抗菌药物的使用,是心内科住院患者MDRPA感染的危险因素;重视无菌技术操作,控制机械性通气的使用,改善住院病室条件是预防心内科MDRPA的重要措施.     

西安地区耐亚胺培南铜绿假单胞菌感染危险因素

目的分析某地区耐亚胺培南铜绿假单胞菌（IRPA）感染的危险因素,为控制IRPA感染提供参考。方法 随机选取西安地区4所三级医院2013年2-10月IRPA感染患者103例（病例组）,同期对亚胺培南敏感的铜绿假单胞菌感染患者103例（对照组）,对IRPA感染危险因素进行分析。结果单因素分析结果显示：高龄、住院时间≥4周、慢性肺部疾病、入住重症监护室、机械通气、分离出IRPA前2周使用过亚胺培南或美罗培南等碳青霉烯类抗生素、早期联合应用抗菌药物是IRPA感染的相关危险因素;选取单因素分析有统计学意义的变量进行logistic多因素回归分析,结果显示,住院时间≥4周（OR95%CI：1.44~139.73）、机械通气（OR95%CI：2.96~267.75）以及分离出IRPA前2周使用过亚胺培南或美罗培南（OR95%CI：2.65~154.34）是IRPA感染的独立危险因素。结论该地区医院应针对IRPA感染危险因素进行干预,以期降低IRPA感染的风险。     

亚胺培南/西司他丁和美罗培南治疗机械通气患者痰分离铜绿假单胞菌的耐药风险差异

目的了解亚胺培南/西司他丁、美罗培南治疗机械通气患者多重耐药铜绿假单胞菌感染的耐药情况及药物疗效。 方法选取某院2010年1月-2015年12月痰培养为耐药铜绿假单胞菌的78例机械通气患者,分为亚胺培南/西司他丁治疗组（44例）和美罗培南治疗组（34例）,比较两组患者的基础状况,细菌对所用抗菌药物产生耐药的时间,以及药物疗效差异。 结果两组患者的基础资料具有可比性,应用亚胺培南/西司他丁和美罗培南治疗前,两组患者分离的铜绿假单胞菌对喹诺酮类、头孢他啶、哌拉西林、阿米卡星的耐药情况比较,差异均无统计学意义（均P>0.05）。应用抗菌药物治疗至第6天,亚胺培南治疗组和美罗培南治疗组患者对所使用的抗菌药物耐药率（22.73% vs 8.82%）比较,差异无统计学意义（P>0.05）;治疗至第8、10、12天,亚胺培南治疗组耐药率分别为40.91%、77.27%、97.73%,均高于美罗培南治疗组（分别为17.65%、32.35%、44.12%;均P<0.05）。不同抗菌药物治疗后铜绿假单胞菌产生耐药的平均时间：亚胺培南/西司他丁治疗组为9.0 d,美罗培南治疗组为13.5 d。两组患者疗效（64.71% vs 74.19%）比较,差异无统计学意义（P=0.41）。结论应用亚胺培南/西司他丁治疗机械通气患者多重耐药铜绿假单胞菌感染发生耐药的风险高于美罗培南,治疗第7天两组患者药物疗效无明显差异。     

嗜麦芽寡养单胞菌所致医院感染及危险因素分析

目的了解嗜麦芽寡养单胞菌医院感染现状及相关危险因素。方法将临床分离引起医院感染的嗜麦芽寡养单胞菌30株,经VITEK-Ⅱ微生物鉴定系统重新鉴定,微量肉汤稀释法监测14种抗菌药物的最低抑菌浓度（MIC）;1∶1病例对照研究,Logistic多因素回归分析筛选出导致该菌感染的危险因子。结果30株嗜麦芽寡养单胞菌对亚胺培南、美罗培南、头孢噻肟、氨曲南、阿米卡星高度耐药;但对头孢哌酮/舒巴坦、哌拉西林/他唑巴坦、复方新诺明、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%、60.0%;独立危险因素为机械通气（OR=7.629）和住院时间〉60 d（OR=4.466）。结论嗜麦芽寡养单胞菌对常用抗菌药物呈多重耐药,机械通气和住院时间〉60 d是嗜麦芽寡养单胞菌医院感染的独立危险因素。     

A bacteriological study of multiple-drug-resistant Pseudomonas aeruginosa isolates derived from 2 patients

We investigated the isolation circumstances of multiple-drug-resistant Pseudomonas aeruginosa (MDRP) in the UOEH hospital and the bacterial analysis of isolated MDRP. From January to October 2003, MDRP was isolated from 2 patients. During this period, the isolation frequency of MDRP was 0.57% (2/350). Case 1 had 2 MDRP isolates from catheter urine, and case 2 had 5 MDRP isolates from pus. Regarding serotype, 2 isolates from case 1 were B type and the other 16 isolates from case 2 were E type. Pyomelanin was produced by 9 isolates of 16 E type isolates. The same PFGE patterns were observed in 2 isolates from case 1; that is, 9 pyomelanin producers from case 2 and the other 7 isolates from case 2, respectively. Metallo-beta-lactamase was produced by 2 isolates from case 1. bla(IMP) was detected from the 2 isolates by PCR, and the clones from case 1 were quite different from the clones from case 2. Regarding the pyomelanin producing isolates from case 2, although the clones were the same genetically, the MICs of imipenem and meropenem increased from 8 to > 32 microg/ml with the progress of time. In the UOEH hospital, 6 patients with MDRP isolates have been isolated so far, but these 6 patients are not correlated with each other. It is important that we detect and report MDRP as early as possible to prevent nosocomial infection.     

老年机械通气患者铜绿假单胞菌药敏分析

目的：提供2002年老年机械通气患者痰铜绿假单胞菌对16种抗菌药物药敏结果，更好地指导临床选用抗生素，方法：对2002年1－6月30例老年气管切开患者痰培养的94例铜绿假单胞菌及32例气管插管患者痰培养的63例铜绿假单胞菌进行分析，药物敏感采用纸片法（Kirby-Bauer)测定。结果：铜绿假单胞菌对阿米卡星敏感率为66．9％，对美罗培南，亚胺培南敏感率分别为47．1％、44．7％，头孢他啶45％，头孢吡肟43％，哌拉西林40．4％，环丙沙星39．2％，对庆大霉素，阿奇霉素，复方新诺明，头孢噻肟耐药率在87％－100％，结论：老年机械通气患者铜绿假单胞菌对大多数抗菌药物耐药，对抗菌药物敏感性≥40％的抗菌药物为阿米卡星，美罗培南，头孢他啶，亚胺培南，头孢吡肟，哌拉西林。     

Identification of patients with Pseudomonas aeruginosa respiratory tract infections at greatest risk of infection with carbapenem-resistant isolates.

OBJECTIVE: To create a clinical tool based on institution-specific risk factors to estimate the probability of carbapenem resistance among Pseudomonas aeruginosa isolates obtained from infected patients. By better estimating the probability of carbapenem resistance on the basis of patient-specific factors, clinicians can refine their empirical therapy for P. aeruginosa infections and potentially maximize clinical outcomes by increasing the likelihood of appropriate empirical antimicrobial therapy. DESIGN: A retrospective, cross-sectional study. SETTING: Tertiary care academic hospital. PATIENTS: All adult inpatients who had a respiratory tract infection due to P. aeruginosa between January 2001 and June 2005. INTERVENTION: Data on demographic characteristics, antibiotic history, and microbiology were collected. Log-binomial regression was employed to identify predictors of carbapenem resistance among P. aeruginosa isolates and to devise the clinical prediction tool. RESULTS: Among 351 patients with P. aeruginosa infection, 44% were infected with carbapenem-resistant P. aeruginosa strains. Independent predictors of carbapenem resistance were prior receipt of mechanical ventilation for 11 days or more, prior exposure to fluoroquinolones for 3 days or more, and prior exposure to carbapenems for 3 days or more. CONCLUSIONS: With carbapenem resistance rates among P. aeruginosa isolates on the rise at our institution, the challenge was to identify patients for whom carbapenems would remain an effective empirical agent, as well as the patients at greatest risk for infection with carbapenem-resistant strains. The clinical prediction tool accurately estimated carbapenem resistance among this risk-stratified cross-sectional study of patients with P. aeruginosa infection. This tool may be an effective way for clinicians to refine their selection of empirical antibiotic therapy and to maximize clinical outcomes by increasing the likelihood of appropriate antibiotic treatment.     

老年患者肺部感染铜绿假单胞菌的危险因素及耐药性分析

目的探讨老年患者肺部感染铜绿假单胞菌(PAE)的危险因素及耐药现状,为临床医师诊断与治疗疾病提供依据。方法细菌培养鉴定按照《全国临床检验操作规程》进行;药敏试验采用K-B法。结果老年患者肺部感染的201株PAE对亚胺培南、美罗培南、哌拉西林/他唑巴坦、头孢哌酮/舒巴坦耐药率较低,分别为1.5%、1.5%、15.4%、14.4%,耐药率>40.0%的抗菌药物有磺胺甲噁唑/甲氧苄啶、庆大霉素、氨曲南、环丙沙星、哌拉西林。结论加强医院感染管理,降低老年患者医院感染发生率。     

老年呼吸机相关性肺炎感染铜绿假单胞菌的耐药性分析

目的研究老年呼吸机相关性肺炎(VAP)铜绿假单胞菌(PAE)感染及耐药特征,为临床合理选用抗菌药物提供依据。方法对256例使用呼吸机治疗的老年住院患者进行目标监测,对分离的铜绿假单胞菌采用纸片扩散法进行药敏试验,并对抗菌药物耐药结果进行回顾性分析。结果 63株铜绿假单胞菌对阿米卡星的耐药率最低,为23.81%,其次为庆大霉素、头孢哌酮/舒巴坦、哌拉西林/他唑巴坦、亚胺培南、美罗培南、左氧氟沙星,耐药率为34.92%～53.97%,对其余8种抗菌药物的耐药率为55.56%～100.00%;共检出34株耐亚胺培南PAE,3株泛耐药菌株。结论铜绿假单胞菌对常用抗菌药物呈多药耐药;VAP感染已十分严重,应引起临床医师的重视;治疗应选择科学的联合用药方案;首选药物为头孢哌酮/舒巴坦、哌拉西林/他唑巴坦、亚胺培南、美罗培南。     

医院铜绿假单胞菌性肺炎对抗菌药物耐药性及死亡率相关性研究

目的 探讨铜绿假单胞菌引起的医院内肺炎患者抗菌药物的耐药率及其可能的死亡相关危险因素.方法 采用前瞻性队列临床研究,对中山医院外科重症监护病房(SICU) 2007年1月-2010年12月气管插管和机械通气时间＞48 h,且首次痰培养检出铜绿假单胞菌的53例患者,采用K-B法抗菌药物敏感试验,记录患者生命体征、通气参数、治疗方案,并随访28 d死亡率.结果 在8种常用的抗菌药物中阿米卡星耐药率最低,为15.1％,其次为头孢哌酮/舒巴坦、美罗培南、头孢他啶、头孢吡肟、亚胺培南,哌拉西林/他唑巴坦耐药率最高为47.2％,多药耐药率为32.1％;53例患者中,17例死亡,11例在28 d内死亡;死亡组铜绿假单胞菌对哌拉西林/他唑巴坦、亚胺培南耐药率和多药耐药率分别为76.5％、58.8％和58.8％,非死亡组分别为33.3％、27.8％和19.4％(P＜0.05);死亡患者中,耐亚胺培南患者的生存时间少于非耐药者(P=0.025);多因素分析年龄、机械通气时间、哌拉西林/他唑巴坦耐药、多药耐药和死亡率明显相关.结论 死亡患者中,对亚胺培南耐药患者生存时间明显缩短;年龄、机械通气时间、多药耐药、哌拉西林/他唑巴坦耐药是住SICU患者铜绿假单胞菌感染后独立的危 险因素.     

Distribution of Class 1–3 Integrons in Carbapenem-Resistant Pseudomonas aeruginosa Isolated from Inpatients in Shiraz,South of Iran

BackgroundHealth-care-associated infection (HAI) is effect on patients for the time of staying in the hospital. Opportunistic pathogens including Pseudomonas aeruginosa are the most dangerous biological agents in nosocomial infections. This study aimed to assess the prevalence of 3 classes of integrons carrying to carbapenem resistance in P. aeruginosa strains collected from Nemazee hospital.MethodsThis cross-sectional study was conducted on clinical P. aeruginosa isolates were collected from Nemazee hospital. The identification of the isolates was performed by routine biochemical tests. Antimicrobial sensitivity testing was determined using the disk diffusion method against imipenem and meropenem. The int1, int2 and int3 genes were detected using the polymerase chain reaction (PCR).ResultsSeventy-five clinical isolates of P. aeruginosa were recovered from various clinical infections. A carbapenem-resistant phenotype was detected in 42.7% (imipenem) and 29.3% (meropenem) of isolates. As the PCR results, 48 (64%) and 15 (20%) isolates were identified as being positive for class 1 and class 2 integrons, respectively. Class 3 integrons were not found among the studied isolates.ConclusionsOur data demonstrate the importance of class 1 and 2 integrons in carbapenem resistant P. aeruginosa strains. Therefore, integrons play an important role in acquisition and dissemination of carbapenem resistance genes among these pathogens, so, management of infection control policies and the appropriate use of antibiotics is essential for control the spreading of antibiotics resistance genes.     

铜绿假单胞菌耐药性及泛耐药临床因素分析

目的分析某院铜绿假单胞菌感染患者耐药情况及发生泛耐药的相关临床危险因素。方法回顾性分析该院2008年1月1日-2009年5月1日间分离的538株铜绿假单胞菌对18种常用抗菌药物的耐药状况,并对其中泛耐药铜绿假单胞菌感染患者（泛耐药组,28例）的住院资料与同期非泛耐药铜绿假单胞菌感染患者（对照组,48例）进行比较。结果538株铜绿假单胞菌对阿米卡星和哌拉西林/他唑巴坦较为敏感,耐药率分别为18.40%和27.70%;而对亚胺培南、美罗培南、头孢他啶及环丙沙星的耐药率较高,分别为69.52%、56.88%、45.91%和56.88%。检出泛耐药铜绿假单胞菌28株,占5.20%。对泛耐药组与对照组患者的分析表明,泛耐药铜绿假单胞菌感染的危险因素有：气管插管、长时间入住重症监护室（ICU）及长期联合应用抗菌药物。结论铜绿假单胞菌对多种抗菌药物耐药率较高,尤其对亚胺培南耐药率增加,应引起临床高度重视。对于入住ICU及应用多种抗菌药物的患者,尤其是应用机械通气者,应警惕泛耐药铜绿假单胞菌感染。     

2010年医院感染主要革兰阴性杆菌的分布及耐药性特点

目的 探讨从医院感染患者中分离的革兰阴性杆菌分布及耐药性,为治疗医院感染患者提供依据.方法 收集2010年285例住院患者医院感染革兰阴性杆菌的相关资料进行回顾性分析.结果 共检出革兰阴性杆菌305株,主要为铜绿假单胞菌、大肠埃希菌、肺炎克雷伯菌、鲍氏不动杆菌、嗜麦芽寡养单胞菌和阴沟肠杆菌;肠杆菌科细菌对亚胺培南和美罗培南的耐药率为1.4％和2.0％;铜绿假单胞菌对亚胺培南、美罗培南的耐药率为34.0％、32.1％;鲍氏不动杆菌对亚胺培南、美罗培南的耐药率为28.9％和31.1％.结论 亚胺培南和美罗培南对肠杆菌科仍保持高活性,但鲍氏不动杆菌、铜绿假单胞菌的耐药性已增加,应予以重视.     

Risk factors for recovery of imipenem- or ceftazidime-resistant pseudomonas aeruginosa among patients admitted to a teaching hospital in Brazil.

BACKGROUND: The prevalence of resistance to imipenem and ceftazidime among Pseudomonas aeruginosa isolates is increasing worldwide. OBJECTIVE: Risk factors for nosocomial recovery (defined as the finding of culture-positive isolates after hospital admission) of imipenem-resistant P. aeruginosa (IRPA) and ceftazidime-resistant P. aeruginosa (CRPA) were determined. DESIGN: Two separate case-control studies were conducted. Control subjects were matched to case patients (ratio, 2:1) on the basis of admission to the same ward at the same time as the case patient. Variables investigated included demographic characteristics, comorbid conditions, and the classes of antimicrobials used. SETTING: The study was conducted in a 400-bed general teaching hospital in Campinas, Brazil that has 14,500 admissions per year. Case patients and control subjects were selected from persons who were admitted to the hospital during 1992-2002. RESULTS: IRPA and CRPA isolates were obtained from 108 and 55 patients, respectively. Statistically significant risk factors for acquisition of IRPA were previous admission to another hospital (odds ratio [OR], 4.21 [95% confidence interval {CI}, 1.40-12.66]; P=.01), hemodialysis (OR, 7.79 [95% CI, 1.59-38.16]; P=.01), and therapy with imipenem (OR, 18.51 [95% CI, 6.30-54.43]; P<.001), amikacin (OR, 3.22 [95% CI, 1.40-7.41]; P=.005), and/or vancomycin (OR, 2.48 [95% CI, 1.08-5.64]; P=.03). Risk factors for recovery of CRPA were previous admission to another hospital (OR, 18.69 [95% CI, 2.00-174.28]; P=.01) and amikacin use (OR, 3.69 [95% CI, 1.32-10.35]; P=.01). CONCLUSION: Our study suggests a definite role for several classes of antimicrobials as risk factors for recovery of IRPA but not for recovery of CRPA. Limiting the use of only imipenem and ceftazidime may not be a wise strategy to contain the spread of resistant P. aeruginosa strains.     

Risk factors for imipenem-resistant Pseudomonas aeruginosa: a comparative analysis of two case-control studies in hospitalized patients

Risk factors for acquisition of imipenem-resistant Pseudomonas aeruginosa by hospitalized patients were assessed at a tertiary care hospital. Two case-control studies with different control groups were used. In Study 1, patients with imipenem-resistant P. aeruginosa (IRPA) (case group) were compared with patients selected at random from the same unit. In Study 2, the case group was compared with patients with imipenem-susceptible P. aeruginosa (ISPA). Ninety-three patients with IRPA and 93 control patients were included in Study 1, and 93 IRPA patients and 65 patients with ISPA were included in Study 2. Carbapenem treatment [odds ratio (OR) 5.82], mechanical ventilation (OR 3.22) and hospital admission in the previous year (OR 2.59) were associated with IRPA in Study 1. An interaction between carbapenem and vancomycin was found to be a significant risk factor for IRPA (OR for carbapenem in patients with vancomycin use 43.71). In Study 2, carbapenem exposure (OR 12.82) and renal failure (OR 5.00) were associated with IRPA. Our study confirmed that carbapenem exposure is the main risk factor for IRPA, and found that the use of both carbapenem and vancomycin can increase this effect.     

医院感染革兰阴性杆菌的分布及耐药性调查分析

目的 探讨医院感染革兰阴性杆菌的构成比及耐药性现状,为临床医师抗感染治疗提供实验室依据.方法 细菌培养按照《全国临床检验操作规程》进行;菌株鉴定采用法国生物梅里埃公司ATB Expression微生物分析仪;药物敏感试验采用CLSI推荐的K-B法,数据统计分析采用WHONET最新版本.结果 1087株革兰阴性杆菌对常用抗菌药物均表现出不同程度的耐药性,肠杆菌科细菌对碳青霉烯类抗菌药物美罗培南、亚胺培南100.0％敏感;但鲍氏不动杆菌分别对亚胺培南、美罗培南出现了45.5％、44.5％的耐药菌株,铜绿假单胞菌分别对亚胺培南、美罗培南出现了30.5％、31.7％的耐药菌株.结论 医院感染革兰阴性杆菌的耐药性已非常严重,应加强合理使用抗菌药物的管理,预防与控制多药耐药细菌导致的医院感染暴发流行.     

Resistance to imipenem among selected gram-negative bacilli in the United States.

OBJECTIVES: Identification of imipenem resistance among selected gram-negative bacilli, especially Pseudomonas aeruginosa and Enterobacter species. METHODS: We analyzed 1986-1990 National Nosocomial Infection Surveillance (NNIS) data from 3,316 P aeruginosa isolates and 1,825 Enterobacter species isolates for which susceptibility results to imipenem were reported. RESULTS: For P aeruginosa, 11.1% of the isolates were resistant to imipenem; 16.1% were either intermediate-susceptible or resistant to the drug. A logistic regression model found that resistance was more common among P aeruginosa isolated from the respiratory tract, patients in intensive care units, and in teaching hospitals. Additionally, resistance to imipenem increased by 25% in teaching hospitals from 1986-1988 to 1989-1990. For Enterobacter species, 1.3% of the isolates were resistant to imipenem; 2.3% were either intermediate-susceptible or resistant to the drug. However, imipenem resistance for these isolates did not differ between the two periods and was not more common in patients in an intensive care unit or infections at any specific site. CONCLUSIONS: The frequency of resistance to imipenem is greater among P aeruginosa than among Enterobacter species. Resistance to imipenem among the P aeruginosa isolates is more common from strains isolated from patients with nosocomial infections in an intensive care unit, from the respiratory tract, and from teaching hospitals. Resistance appears to be increasing among nosocomial P aeruginosa isolated in teaching hospitals.     

Nosocomial outbreak of Pseudomonas aeruginosa infections related to a flexible bronchoscope

An outbreak of Pseudomonas aeruginosa infections affecting 17 patients was detected in the 27-bed intensive care unit (ICU) of a community hospital from 1 July to 30 September 2003. An ambidirectional cohort study was conducted to identify the risk factors for infection. Nosocomial infections were defined using the criteria of the Centers for Disease Control and Prevention. Random arbitrary polymorphic DNA-polymerase chain reaction was used for genotypic characterization. Logistic regression analyses demonstrated that case patients were more likely than non-cases to have had a longer stay in the ICU, and to have undergone mechanical ventilation and antimicrobial treatment. The multi-variate analysis identified recent bronchoscopy [risk ratio (RR) 3.8, 95% confidence interval (CI) 2.5-3.9] and exposure to an infected patient (RR 2.9, 95% CI 1.1-3.7) as independent risk factors. Molecular analysis showed that of the nine isolates available, four patients had a similar strain. The factor with the strongest influence on the risk of death was infection with P. aeruginosa (RR 2.1, 95% CI 1.0-2.4, P=0.04). A combined infection control strategy was implemented, including strict compliance with isolation precautions and recommendations for cleaning and disinfecting bronchoscopes, and a sharp reduction in the incidence of P. aeruginosa infection followed. It is thought that this outbreak was caused by patient-to-patient transmission and infection from a common source, i.e. the flexible bronchoscope.     

Epidemiological analysis of carbapenem-sensitive and -resistant Pseudomonas aeruginosa

Pseudomonas aeruginosa with decreased levels of meropenem susceptibility were identified in the Royal Infirmary Edinburgh in 2002. Within the affected group of patients, none had meropenem-resistant P. aeruginosa when they arrived in the intensive care unit (ICU). Seven isolates from the ICU were collected five months after the decreased susceptibility to meropenem was identified. In order to investigate if resistance was a problem in P. aeruginosa throughout Edinburgh, both in hospital- and community-acquired isolates, a prospective study was performed. The susceptibilities of 104 P. aeruginosa to imipenem, meropenem, ceftazidime, piperacillin/tazobactam and ciprofloxacin were investigated. Meropenem had the highest activity against these isolates and the lowest MIC(90) (2 mg/L), followed by imipenem (4 mg/L), ciprofloxacin (8 mg/L), piperacillin/tazobactam (16 mg/L) and ceftazidime (32 mg/L). These isolates were also analysed genotypically by pulsed-field gel electrophoresis. Five of the seven ICU isolates were identified, one isolate was 98% similar and the other was 85% similar to the ICU isolates. One isolate from the prospective study had approximately 90% genotype similarity to the six ICU isolates with >/=98% similarity. There was no clonality within the strains from the prospective study and clusters with >90% similarity comprised at five or less isolates. Isolates with the same resistance patterns did not necessarily have the same genotypic profile. Strains isolated from different patients on the same day were also not necessarily related. The conclusions of this study were that while the seven ICU isolates were clonal or highly related, they were not widespread throughout Edinburgh and the P. aeruginosa within Edinburgh were highly varied.     

Clinical surveillance of surgical imipenem-resistant Pseudomonas aeruginosa infection in a Japanese hospital

In order to elucidate any changes in imipenem-resistant Pseudomonas aeruginosa (IRPA) infections in Japan, we examined 511 P. aeruginosa stains isolated from our surgical ward between 1987 and 2001. These isolates were subjected to susceptibility testing against various antipseudomonal agents including imipenem, meropenem, ceftazidime, gentamicin and ciprofloxacin. They were serotyped with the slide agglutination test and genotyped using pulsed-field gel electrophoresis (PFGE). The annual incidences of IRPA infections were particularly high in the early 1990s. Epidemiological investigations revealed that these outbreaks were due to dissemination of hospital-acquired IRPA isolates. Intensive use of imipenem promoted the selection of highly resistant strains. Further study of resistance mechanisms revealed that none of the 110 IRPA strains were metallo-beta-lactamase (MBL) producers. Polymerase chain reaction (PCR) analysis using bla(IMP) specific primers confirmed that no IMP-1 type MBL gene-positive strains were detected from our ward. Susceptibilities of those IRPA strains against other antipseudomonal agents showed relatively low levels, suggesting that imipenem resistance was mainly due to impermeability of the OprD porin. In conclusion, hospital-acquired outbreaks of IRPA were recently reduced by guidelines for, and surveillance of, appropriate use of antimicrobial agents. When the rate of IRPA isolation increases, serotyping should be performed initially and PFGE is required to confirm outbreaks. A computer-assisted genotyping technique is available to perform epidemiological studies of IRPA isolates.