Reassessment of the routine anaerobic culture and incubation time in the BacT/Alert FAN blood culture bottles

A total of 9,130 blood cultures were collected from adult patients with suspected bloodstream infections. The recommended 20 mL sample of blood was divided equally between the aerobic and anaerobic FAN bottles and monitored in the BacT/Alert Microbial Detection System for a total of 5 days. There were 757 clinically significant positive culture pairs from 291 patients. Significant differences were found with greater recovery of Pseudomonas aeruginosa (p < 0.001), Acinetobacter spp. (p = 0.002), coagulase-negative staphylococci other than Staphylococcus epidermidis (p = 0.002), and Candida spp. (p < 0.001) from the aerobic bottle and greater recovery of anaerobic bacteria (p < 0.001) from the anaerobic bottle. Significantly more episodes of P. aeruginosa bacteremia (p < 0.003) and candidemia (p < 0.001) were detected by the aerobic FAN bottle and significantly more episodes of anaerobic bacteremia (p < 0.001) were detected by the anaerobic FAN bottle (Table 2). No other significant differences between systems in their detection of bacteremias were noted. Anaerobic bacteremias were encountered in diverse and often unpredictable clinical settings. All clinically significant episodes of bloodstream infection were detected within 4 days of incubation of their cultures. We conclude routine, rather than selective, use of the anaerobic FAN bottle in the blood culture set and a 4-day incubation of blood cultures in the BacT/Alert aerobic and anaerobic FAN bottles is an appropriate routine procedure.     

Polymicrobial candidemia

We conducted a retrospective review of the clinical data on patients with polymicrobial candidemia during a nine-year period (1992-2000) at our tertiary care University Hospital. Also, the clinical features of patients with polymicrobial vs monomicrobial candidemia were compared. There were 16 (5.2%) patients with multiple candidal species in blood among 303 patients with candidemia. Patients' age varied from 21-85 years (median 52 years); they had serious underlying co-morbidities with prolonged hospitalization (median duration 13 days); all had intravenous vascular catheters, had been exposed to multiple antibiotics and were heavily colonized with Candida. Concomitant serious bacterial infections were common (56%). Candida albicans was isolated from blood in 11 of 16 patients; other species were C. glabrata (7 patients), C. tropicalis (6 patients) and C. parapsilosis (4 patients). Sixty seven percent (8 of 12) patients had causative Candida species isolated from vascular catheter tip culture. Polymicrobial candidemia occurred in sicker, non-oncologic patients with frequent concomitant bacterial infections, as compared to those with monomicrobial candidemia. Crude mortality was 43%, a rate similar to that seen with monomicrobial candidemia. Polymicrobial candidemia is uncommon, seen in hospitalized patients with multiple co-morbidities and heavy candidal colonization; removal of vascular catheter and institution of antifungal therapy are important therapeutic maneuvers.     

Impact of yeast-bacteria coinfection on the detection of Candida sp. in an automated blood culture system

Invasive candidiasis remains a major cause of morbidity and mortality. It is now well known that an early diagnosis contributes to the patients' outcome. Blood cultures, which are the first-line test in case of bloodstream infection suspicion, can be carried out using fungus-selective medium (containing antibiotics) or standard microorganism medium allowing both bacterial and fungal growth. Some patients can suffer from polymicrobial sepsis involving bacteria and yeasts, so we decided to investigate in blood cultures the influence of the presence of bacteria on fungal development. Simulated blood cultures were performed using Candida albicans or C. glabrata coincubated with Escherichia coli or Staphylococcus aureus at different concentrations. The results showed that, in a standard microorganism medium, bacterial growth could hide the fungal development. Thus, in patients at risk of invasive candidiasis, the use of a specific fungal medium could improve the diagnosis and allow an earlier efficient antifungal treatment.     

Clinical significance of Candida colonization of intravascular catheters in the absence of documented candidemia

In order to assess the significance of Candida colonization of intravascular catheters (IVC) in patients without documented candidemia, we retrospectively reviewed all Candida-positive IVC tip cultures over a 4-year period. Cases were defined as those with a culture yielding ≥15 colony-forming units of Candida spp. that either did not have blood cultures (BC) taken or had concomitant BC negative for Candida. Patients were followed up until death or 8 months after discharge. Risk factors for poor outcome following IVC removal (death, candidemia, or Candida-related complication) were analyzed. We analyzed a total of 40 patients. Overall mortality was 40.0%, with no death directly attributed to Candida infection. Twenty-two patients received antifungal therapy at the time of IVC removal. Only 1 patient developed a metastatic complication (chorioretinitis) attributable to transient candidemia (2.5% of the global cohort and 3.7% among those with concomitant BC). There were no cases of subsequent candidemia. In the multivariate analysis, the use of antifungal therapy did not show any impact on the risk of poor outcome. The risk of invasive disease in patients with isolated IVC colonization by Candida seems to be low. Nevertheless, the initiation of systemic antifungal therapy should be carefully considered in such context.     

Polymicrobial bacteremia in critically ill patients

Objective To characterize the epidemiology of polymicrobial bacteremia (PMB) among critically ill patients.Design Prospective clinical study.Setting University medical center.Patients All patients with positive blood cultures in a medical-surgical ICU.Measurements PMB represents 8.4% of all true bacteremia in our ICU. Most of these patients were post-operative but none had malignancies or significant immunodepression. Over three-quarters of the episodes were nosocomial. No significant differences in factors associated with PMB were found when they were compared with a cohort of 154 monomicrobial episodes. Enterobacteriaceae were the most common organisms. Intravascular devices (42.8%) were the most common source of PMB, followed by intra-abdominal origin (21.4%). The overall mortality was 7.1%, a lower rate than has previously been described.Conclusions We suggest catheter replacement in patients who develop PMB and improving techniques of catheter maintenance in order to reduce its incidence.     

Reevaluation of anaerobic blood cultures in a Veteran population

BACKGROUND: Studies suggest that the selective use of anaerobic blood cultures may represent a more cost-effective laboratory approach when anaerobic bacterial infection is suspected. METHODS: A 5-year retrospective study was done at a Veterans' Affairs hospital to determine the utility of routinely including anaerobic blood culture when sampling for bacteremia. RESULTS: A total of 22,075 anaerobic blood cultures were collected from our adult population. Significant anaerobic pathogens were isolated from only 0.14% of these blood cultures. An anaerobic infection could have been suspected in 92% of our patients. CONCLUSIONS: Significant anaerobic bloodstream infections occurred in only 0.14% of blood cultures. In addition, the majority of the patients identified with anaerobic bacteremia had clinical conditions that would have suggested a high likelihood of anaerobic bacteremia. These observations suggest that selective rather than routine use of anaerobic blood cultures may be appropriate in a veteran population.     

2010~2011年血培养病原菌分布和耐药性分析

目的 研究该院2010~2011年血培养病原菌分布及耐药性.方法 回顾性分析该院2010~2011年血培养标本病原菌检出情况及其药敏试验结果.结果 10 128例血培养标本共检出病原菌1 276株,革兰阴性杆菌、革兰阳性球菌及真菌分别占57.1%(728/1 276)、33.4%(426/1 276)、9.5%(121/1 276).革兰阳性球菌以表皮葡萄球菌、金黄色葡萄球菌、肠球菌等为主,对万古霉素、替考拉宁和利奈唑胺均敏感;粪肠球菌耐药率低于屎肠球菌.革兰阴性菌以大肠埃希菌、肺炎克雷伯菌、鲍曼不动杆菌、铜绿假单胞菌为主;超广谱β内酰胺酶阳性肠杆菌科细菌耐药率高于阴性株.碳青霉烯类对大肠埃希菌、肺炎克雷伯菌的抗菌活性强于铜绿假单胞菌、鲍曼不动杆菌.真菌以白色假丝酵母菌为主.结论 2010~2011年该院血液感染患者较多,应重视血培养标本检测及致病菌耐药性分析,应根据药敏实验结果 及耐药趋势合理应用抗菌药物.     

降钙素原在血流感染病原学诊断中的价值

目的评价降钙素原(procalcitonin,PCT)血清浓度鉴别诊断血流感染(bloodstream infection,BSI)病原学的准确性。方法收集2015年1月至2020年6月于中日友好医院重症监护室(ICU)诊断为BSI且阳性血培养同时进行PCT检测的患者资料,以血培养当天的参数计算序贯器官衰竭评分(sequential organ failure assessment,SOFA),比较不同病原体感染者之间各指标的差异,并用受试者工作特征(receiver operating characteristic,ROC)曲线分析生物标志物PCT对单一病原体感染的鉴别诊断价值。结果在1456例BSI患者中,单一细菌或念珠菌感染分别为1261例(86.6%)和80例(5.5%),混合感染115例(7.9%);28 d病死率为24.5%(356/1456),60 d病死率为30.6%(446/1456);无论28 d还是60 d病死率,混合感染组均明显高于细菌菌血症组以及念珠菌血症组。PCT在革兰阴性菌(gram-negative bacteria,GNB)菌血症中显著高于革兰阳性菌(gram-positive bacteria,GPB)菌血症和念珠菌血症{3.4μg/L[95%可信区间(95%CI)0.7~17.0μg/L]比1.3μg/L(95%CI 0.4~7.3μg/L);3.4μg/L(95%CI 0.7~17.0μg/L)比1.1μg/L(95%CI 0.4~3.4μg/L);P<0.01}。ROC曲线分析显示:①PCT鉴别诊断单一细菌菌血症与念珠菌血症的最佳截断值为7.25μg/L,特异性可达90.0%,ROC曲线下面积(area under ROC curve,AUROC)为0.612(95%CI 0.533~0.691);当PCT>0.51μg/L,诊断细菌菌血症的敏感性可达73.3%;②PCT鉴别诊断GNB菌血症与念珠菌血症的最佳截断值为7.32μg/L,特异性为90.0%;AUROC为0.695(95%CI 0.614~0.776);当PCT>0.51μg/L时,诊断GNB菌血症的敏感性为84.9%;③PCT鉴别诊断GNB菌血症与GPB菌血症的最佳截断值为0.52μg/L,敏感性为84.9%,AUROC为0.713(95%CI 0.672~0.755);当PCT>7.36μg/L,诊断GNB菌血症的特异性可达80.1%。结论PCT能够提供BSI患者可能的病原学方面的额外信息,尤其是较高的PCT水平往往提示GNB菌血症可能。     

综合ICU血培养阳性标本病原菌的分布及耐药性分析

目的:分析近5年我院综合ICU血培养阳性标本病原菌的分布及耐药性情况。方法:回顾性调查分析2009-01-2013-12住院患者临床血培养阳性标本药敏试验结果。结果:共分离出病原菌208株,其中革兰阳性球菌占61.5%,革兰阴性杆菌占34.6%,真菌占3.9%。凝固酶阴性葡萄球菌(CNS)(39.4%)最多,其余依次为肠杆菌科细菌(27.4%),金黄色葡萄球菌(11.5%)、肠球菌属细菌(8.7%)、非发酵革兰阴性杆菌(6.3%)、真菌。未发现对万古霉素、替考拉宁、利奈唑胺耐药的葡萄球菌。屎肠球菌中检出耐万古霉素和替考拉宁耐药菌1株。肺炎克雷伯菌对碳氢酶烯类耐药率为16.7%,未检出其他耐碳氢酶烯类的肠杆菌科菌株。头孢哌酮-舒巴坦对非发酵革兰阴性杆菌耐药率在20.0%以下。真菌以白色念珠菌为主,对目前主要抗真菌药物敏感率均较高。结论:综合ICU是血流感染的高发区,了解本科室血培养阳性标本病原菌的分布以及进行耐药性监测,对制定经验治疗方案,指导抗生素的临床合理用药具有一定的参考价值。     

Development of subsequent bloodstream infection in patients with positive Hickman catheter blood cultures and negative peripheral blood cultures

There are limited data on the incidence of subsequent bloodstream infection (BSI) and the effect of systemic antibiotics in patients who had positive catheter-drawn blood cultures (CBC) and negative peripheral blood cultures (PBC). We retrospectively reviewed all paired blood cultures from patients with Hickman catheter in the hematology-oncology ward between January 1997 and December 2008. There were 112 episodes with positive CBC and negative PBC. Nine episodes (8.0%; 95% CI, 3.0-13.1%) led to subsequent BSI within 28 days. Subsequent BSI developed in 6 of 31 episodes (19%) where empiric antibiotics were inappropriate but in 3 of 81 episodes (4%) where empiric antibiotics were appropriate (P = 0.01). Subsequent candidemia (50%, 2 of 4) was more common than subsequent bacteremia (6%, 7 of 108) (P = 0.03). In conclusion, for patients with positive CBC and negative PBC, the overall incidence of subsequent BSI was 8.0%, and inappropriate empiric antibiotics was associated with subsequent BSI.     

Distribution and antimicrobial resistance of bloodstream pathogens in surgical and medical ICUs北大核心CSCD

Objective To analyze the distribution and antimicrobial resistance of bloodstream pathogens in surgical intensive care unit (SICU) and medical intensive care unit (MICU) of Fujian Provincial Hospital in the past four and half years for better use of antimicrobial drugs. Methods A retrospective analysis was carried out for the bloodstream pathogens isolated from SICU and MICU patients from January 2012 to June 2016. The clinical data and outcomes of patients were also reviewed. Results A total of 329 strains of isolates were recovered from blood samples in SICU, including gram-negative bacteria (53.5%), gram-positive bacteria (39.2%), and fungi (7.3%); 258 strains were collected from MICU, including gram-negative bacteria (57.8%), gram-positive bacteria (36.0%), and fungi (6.2%). A. baumannii, K. pneumonia and E. coli were the top three gram-negative species in both SICU and MICU. The main gram-positive species were coagulasenegative Staphylococcus and Enterococcus faecium. Overall, 386 cases of bloodstream infections were diagnosed, including 226 cases in SICU (202 cases of single bacterial infection and 24 cases of multiple bacterial infection), and 160 cases in MICU (138 cases of single bacterial infection and 22 cases of multiple bacterial infection). A. baumannii isolates showed significantly higher rate of resistance to antibiotics in SICU than in MICU, while the K. pneumoniae and E. coli isolates in MICU showed higher resistance rates to cephalosporins, quinolones, penicillins and carbapenems than the corresponding isolates in SICU. The coagulase negative Staphylococcus and E. faecium isolates in MICU were associated with significantly higher resistance rates to quinolones and tigecycline than those strain in SICU. The bloodstream infections due to K. pneumoniae, E. coli and E. faecium were associated with higher mortality in MICU than in SICU, while the bloodstream infections due to A. baumannii were associated with higher mortality in SICU than in MICU. The total mortality rate of bloodstream infections was higher in MICU than in SICU. Conclusions SICU and MICU share similar profile of main bloodstream pathogens even though the disease spectrum was different between SICU and MICU. All the bloodstream pathogens isolated from MICU patients except A. baumannii showed significantly higher antimicrobial resistance rates than the isolates from SICU. The mortality rate associated with bloodstream infection was also higher in MICU patients than in SICU. © 2018, Editorial Department of Chinese Journal of Infection. All rights reserved.     

80株深部真菌感染阳性血培养及药敏结果分析

目的　分析 80株血培养真菌阳性标本及其药敏结果 ,寻找深部真菌感染特点。方法　血培养使用Back/Alert血培养仪。分离使用科玛嘉培养基。真菌和细菌鉴定使用VitekAMS 6 0微生物分析仪。药敏使用微量MIC法。HCMV检验使用PCR和RT PCR方法。结果　 80株真菌分布在 4个菌属中 ,以念珠菌属为主占 91 2 5%。获得阳性结果时间平均 31 80h ,72h内获得结果者 76株占 95 0 %。对 5种真菌作药敏试验 ,5 氟胞嘧啶敏感率最高 ( 97% ) ,特比奈芬最低 ( 35% )。 51 2 5%( 4 1 /80 )患者从血以外的其他标本获得与血中分离菌种一致的真菌。 80例患者中 4 6例伴随有细菌或病毒感染 ,占患者57 50 %。真菌感染多见于免疫功能低下者 ,本组 80例患者中各种肿瘤占 6 9例 ( 86 2 5% )。结论　血培养阳性是患者深部真菌感染的确证依据 ,多为在免疫功能低下者发生的院内感染 ,多系统真菌感染多为临床致死原因。真菌药敏实验结果给临床治疗提供了有参考价值的信息     

真菌血症31例临床分析

目的对真菌血症的临床及微生物学特征进行分析,为临床诊治提供参考。方法收集2004年8月—2005年12月期间我院31例真菌血症患者的临床资料进行回顾分析。结果超过80%的真菌血症患者患有2种或以上的基础疾病。半数以上患者均有导管留置,而且83．9%患者在血培养采样前1周内均不同程度使用抗菌药物。31例真菌血症中,24例(77．4%)与念珠菌有关,但仅3例由白念珠菌引起,念珠菌血症患者的病死率为45．8%。不同念珠菌对抗真菌药物存在不同程度的耐药率。结论真菌血症多发生于基础疾病严重者,由非白念珠菌导致的败血症在真菌血症中占很大比例;部分真菌对氟康唑、伊曲康唑耐药。     

Acridine orange leukocyte cytospin test for central venous catheter--related bloodstream infection: a pediatric experience

The aim of this study was to evaluate the acridine orange leukocyte cytospin (AOLC) test for the rapid diagnosis of septicemia caused by central venous catheters (CVCs), without removing the catheter, in a pediatric intensive care unit population. Twenty-six patients admitted in the pediatric intensive care unit of Azienda Ospedaliera "Ospedali Riuniti di Bergamo", Italy, were prospectively evaluated for CVC-related infection. Blood for culture was taken from all patients. Quantitative endoluminal cultures of the removed catheter tip by Cleri's technique and semiquantitative superficial cultures of the hub were performed. Gram staining and an AOLC smear were done according to Kite's technique. Four Staphylococcus CVC-related bloodstream infections were identified. CVC colonization was detected in 8 patients. Four had septicemia (Enterococcus faecalis, Escherichia coli, Klebsiella oxytoca, Candida glabrata) without CVC involvement. However, Gram staining and the AOLC test were negative in all cases. We conclude that cytocentrifugation and acridine orange staining of blood withdrawn by Kite's method from an in situ catheter, although simple, quick, and inexpensive, did not aid diagnosis in this pediatric population.     

某三甲医院血培养病原菌分布及耐药分析

目的分析某三甲医院血培养病原菌分布及其耐药性,为临床血流感染(BSI)防控和抗菌药物的合理使用提供依据。方法回顾性分析2014年6月至2016年9月该院住院患者送检的3 241份血培养结果,采用BacT/ALERT 3D和VersaTrek仪器进行血培养,采用VITEK-2Compact和ARIS 2X进行鉴定和药敏试验。结果 3 241份血培养标本中,共分离出病原菌99株,阳性率为3.1%。共分离得到革兰阴性菌42株(42.4%),革兰阳性菌54株(54.5%),真菌3株(3.0%)。分离前3位的革兰阴性菌依次为大肠埃希菌,肺炎克雷伯菌和铜绿假单胞菌;革兰阳性菌依次为:凝固酶阴性葡萄球菌,金黄色葡萄球菌,化脓链球菌。肠杆菌科对亚胺培南、美罗培南、哌拉西林/他唑巴坦、阿米卡星保持100.0%敏感,阳性球菌对万古霉素、利奈唑胺、替考拉宁以及庆大霉素耐药率为0.0%,其余有不同程度耐药。结论大肠埃希菌、凝固酶阴性葡萄球菌和金黄色葡萄球菌是该院血流感染最常见的病原菌,各病原菌对不同抗菌药物耐药性不同,临床需根据药敏试验结果合理选择抗菌药物,减缓耐药菌株的产生。     

婴幼儿血培养分离细菌及其耐药性分析

目的分析住院婴幼儿(≤3个月)血培养分离病原菌的分布及其耐药情况,为临床合理选择抗菌药物治疗血流感染提供参考。方法收集2011年1月至2015年5月该院疑似血流感染住院婴幼儿(≤3个月)血培养阳性标本分离病原菌299株,采用VITEK 2Compact全自动微生物分析仪进行菌株鉴定和药物敏感试验,分析菌株的构成及耐药情况。结果分离的299株病原菌中革兰阳性球菌169株(占56.5%),主要为凝固酶阴性葡萄球菌95株(占31.8%),其次为金黄色葡萄球菌28株(占9.4%);革兰阴性杆菌120株(占40.1%),主要为大肠埃希菌53株(占17.7%);真菌8株(占2.7%);革兰阳性杆菌2株(占0.7%)。药敏结果显示,除万古霉素、利奈唑烷外,革兰阳性球菌对其他所测试的抗菌药物均呈现耐药性;革兰阴性杆菌除对阿米卡星、亚胺培南、美罗培南高度敏感外,对其他所测试的抗菌药物均有耐药性;真菌对所有抗真菌药物高度敏感。结论住院婴幼儿血液感染病原菌以革兰阳性球菌和革兰阴性杆菌为主,耐药情况严峻,临床需合理选择抗菌药物,以提高疗效并减少耐药菌株的产生。     

4541份血培养标本检出病原菌分布及耐药性分析

目的分析该院2013~2014年血培养分离菌的分布特点及耐药情况。方法用BacT/Alert 120全自动血培养仪对4 541份血液标本进行检测,对其鉴定及药敏结果进行回顾分析。结果 4 541份血培养共检出病原菌317株,阳性率为7.0%,革兰阴性杆菌179株,占检出病原菌总数56.5%;革兰阳性菌127株,占检出病原菌总数40.1%;真菌11株,占检出病原菌总数3.4%。其中肠杆菌136株占42.9%,肠杆菌以大肠埃希菌和肺炎克雷伯菌居多,分别占19.0%、14.0%,非发酵菌29株占9.1%,以鲍曼不动杆菌及铜绿假单胞菌为主,分别占5.0%、4.0%,革兰阳性菌以葡萄球菌为主,前4位分别为金黄色葡萄球菌10.0%、表皮葡萄球菌8.0%、溶血葡萄球菌8.0%及人葡萄球菌5.0%。肠杆菌对阿米卡星、哌拉西林/他唑巴坦、亚胺培南、美罗培南较敏感,鲍曼不动杆菌及铜绿假单胞菌对环丙沙星、左氧氟沙星、哌拉西林/他唑巴坦较敏感,葡萄球菌对万古霉素、利奈唑胺、奎奴普丁、替考拉宁敏感。结论菌血症、败血症和真菌血症临床病死率较高,临床医师应加强血液感染患者血液中病原菌的检测,提高治愈率。     

Incidence,risk factors,and predictors of outcome of candidemia. Survey in 2 Italian university hospitals

In recent decades, Candida spp. emerged as the fourth most common cause of nosocomial bloodstream infections. The incidence of candidemia was 0.13 per 100 persons. Eighty-three cases (61%) of candidemia were due to Candida albicans and 53 (39%) to nonalbicans Candida spp. Twelve strains of Candida (9%) had shown in vitro resistance to fluconazole, 5 (4%) to itraconazole, 2 (1.5%) to voriconazole, 12 (9%) to 5-flucytosine, and 1 (0.7%) to amphotericin B. Multivariate logistic regression analysis of risk factors showed that length of hospitalization, presence of a central venous catheter, previous episodes of candidemia or bacteremia, parenteral nutrition, and chronic renal failure were variables independently associated with the development of candidemia. Multivariate logistic regression analysis of prognostic indicators showed that the independent variables associated with poor prognosis were inadequate initial therapy (P < .001) and high APACHE III score (P = .004). The inadequate initial therapy associated with mortality indicates the need for additional investigations to define high-risk patients for beneficial antifungal prophylaxis.     

2015年某院血流感染主要病原菌分布及耐药性分析

目的：了解2015年血培养的病原菌分布及耐药性,为临床血流感染的诊断与治疗提供依据。方法采用 BacT ／A‐lert 3D 全自动血培养仪进行血培养,VITEK‐2 Compact 全自动鉴定药敏仪进行鉴定、药敏试验,采用 WHONET 5．6软件对结果进行统计分析。结果从14208例血培养标本中共分离病原菌1102株,阳性检出率为7．8％,删除同一患者、同一菌株后共552株,其中革兰阳性菌325株,占58．9％;革兰阴性菌210株,占38．0％;真菌17株,占3．1％。凝固酶阴性葡萄球菌的检出率较高,占34．1％,可能与标本采集不规范有关;大肠埃希菌和肺炎克雷伯菌的检出率分别为14．5％和7．6％;耐碳青霉烯类大肠埃希菌检出率为1．3％,而耐碳青霉烯类的肺炎克雷伯菌检出率高达50．0％。真菌对伏立康唑、伊曲康唑保持高度敏感。结论该院血流感染病原菌以凝固酶阴性葡萄球菌为主,其次为大肠埃希菌和肺炎克雷伯菌,多重耐药严重。及时了解血培养中病原菌的变化和耐药变迁,对于指导临床合理使用抗菌药物、减少多重耐药的发生具有重要临床意义。     

Prevalence and epidemiology of microbial pathogens causing bloodstream infections: results of the OASIS multicenter study

Beginning on April 2007, a prospective multicenter study was performed to investigate prevalence and epidemiology of microbial pathogens causing bloodstream infections (BSIs). Twenty microbiology laboratories participated to the survey over a 1-year period. A total of 11,638 episodes of BSI occurred in 11 202 patients, with 8.5% (n=985) of episodes being polymicrobial. Of 12 781 causative organisms, aerobic Gram-negative bacteria were 47.4% (n=6058), whereas Gram-positives accounted for 43.9% (n=5608). The remaining organisms included fungal species (n=924, 7.2%) and anaerobes (n=191, 1.5%). The most prevalent agents were Escherichia coli (21.7%), Staphylococcus aureus (14.9%), Staphylococcus epidermidis (8.2%), Pseudomonas aeruginosa (7.0%), and Enterococcus faecalis (6.3%). Isolates recovered from patients admitted to medical, surgical, and intensive care units accounted for 62.9%, 17.7%, and 19.4% of cases, respectively. BSIs were classified as hospital-acquired in 67.2% of cases. Compared with previous studies, our data show an increasing role of Gram-negative bacteria among both hospital- and community-acquired blood isolates.