Gram stain evaluation of the quality of sputum specimens for mycobacterial culture.

A group of 34 mycobacteria, consisting of 25 Mycobacterium tuberculosis and nine strains of three other species, was isolated from 400 expectorated sputum specimens submitted on 148 patients from county-wide sources. Eight strains (24% of the total) were isolated from specimens evaluated by Gram stain to be oropharyngeal fluids. The remaining 26 strains were isolated from ungradable specimens and those primarily of lower respiratory origin. It was concluded that the random examination of sputum by Gram stain to determine the specimen's quality for mycobacterial isolation is not necessary.     

A 2-year study of Gram stain competency assessment in 40 clinical laboratories

We used a computer-based competency assessment tool for Gram stain interpretation to assess the performance of 278 laboratory staff from 40 laboratories on 40 multiple-choice questions. We report test reliability, mean scores, median, item difficulty, discrimination, and analysis of the highest- and lowest-scoring questions. The questions were reliable (KR-20 coefficient, 0.80). Overall mean score was 88% (range, 63%-98%). When categorized by cell type, the means were host cells, 93%; other cells (eg, yeast), 92%; gram-positive, 90%; and gram-negative, 88%. When categorized by type of interpretation, the means were other (eg, underdecolorization), 92%; identify by structure (eg, bacterial morphologic features), 91%; and identify by name (eg, genus and species), 87%. Of the 6 highest-scoring questions (mean scores, > or = 99%) 5 were identify by structure and 1 was identify by name. Of the 6 lowest-scoring questions (mean scores, < 75%) 5 were gram-negative and 1 was host cells. By type of interpretation, 2 were identify by structure and 4 were identify by name. Computer-based Gram stain competency assessment examinations are reliable. Our analysis helps laboratories identify areas for continuing education in Gram stain interpretation and will direct future revisions of the tests.     

Comparative evaluation of the Limulus assay and the direct Gram stain for detection of significant bacteriuria.

A double-blind study comparing the Limulus in-vitro endotoxin assay with the direct Gram stain of uncentrifuged urine for detection of significant bacteriuria was performed. One-thousand seventy-seven urine specimens were examined by the two methods and the results compared with results of quantitative urine cultures. Two hundred three samples produced growth of greater than 10-5 organisms per ml. urine. The Limulus assay detected 86.2% of these specimens, and 98.8% of urines that contained greater than 10-5 Gram-negative bacilli per ml. The Gram stain procedure detected only 69.5% of urines containing greater than 10-5 organisms per ml. and 74.5% of specimens with greater than 10-5 Gram-negative bacteria per ml. urine. The Limulus assay demonstrated both greater sensitivity and greater specificity than the Gram stain procedure. Moreover, the Limulus test is much less susceptible to errors of interpretation than methods involving microscopy.     

荧光染色技术在精子检测中的应用

近20年来，随着荧光染色技术的不断发展完善，其在检测精子染色质、质膜完整性、线粒体活性、精子获能状态及顶体状态等方面取得成功。荧光染色技术利用荧光染色试剂能特异的与精子染色质、质膜、线粒体和顶体上某些成分结合，在激发光激发下能发出肉眼可见的荧光并在荧光显微镜下观测，从而迅速、准确地了解精子各方面的功能。该技术的应用有助于了解精子的受精能力，为选择助孕方式提供可靠依据，尤其对原因不明不孕症患者的诊断治疗，更见优势。目前多主张两种或三种方法联合使用，如：三重染色法同时检测精子质膜、线粒体活性和项体状态。     

An evaluation of the Gram stain and chocolate agar culture as part of a routine urine culture set-up

A total of 219 urine specimens were Gram stained and inoculated onto 5% sheep blood, eosin methylene blue and chocolate agars. Culture and smear results were evaluated to determine if the Gram stain and chocolate agar culture yielded further meaningful information. Additional information was gained in 42 (19%) of the specimens; however, most of the results were not considered significant. The analysis suggests that a Gram stain and/or chocolate agar culture is not warranted for routine urine culture set-up.     

High positive predictive value of Gram stain on catheter-drawn blood samples for the diagnosis of catheter-related bloodstream infection in intensive care neonates

Catheter-related bloodstream infections (CRBSIs) remain a leading cause of healthcare-associated infections in preterm infants. Rapid and accurate methods for the diagnosis of CRBSIs are needed in order to implement timely and appropriate treatment. A retrospective study was conducted during a 7-year period (2005–2012) in the neonatal intensive care unit of the University Hospital Erasme to assess the value of Gram stain on catheter-drawn blood samples (CDBS) to predict CRBSIs. Both peripheral samples and CDBS were obtained from neonates with clinically suspected CRBSI. Gram stain, automated culture and quantitative cultures on blood agar plates were performed for each sample. The paired quantitative blood culture was used as the standard to define CRBSI. Out of 397 episodes of suspected CRBSIs, 35 were confirmed by a positive ratio of quantitative culture (>5) or a colony count of CDBS culture >100 colony-forming units (CFU)/mL. All but two of the 30 patients who had a CDBS with a positive Gram stain were confirmed as having a CRBSI. Seven patients who had a CDBS with a negative Gram stain were diagnosed as CRBSI. The sensitivity, specificity, positive predictive value and negative predictive value of Gram stain on CDBS were 80, 99.4, 93.3 and 98.1 %, respectively. Gram staining on CDBS is a viable method for rapidly (<1 h) detecting CRBSI without catheter withdrawal.     

The use of Gram stain and matrix-assisted laser desorption ionization time-of-flight mass spectrometry on positive blood culture: synergy between new and old technology

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is promising as an alternative to more costly and cumbersome methods for direct identifications in blood cultures. We wanted to evaluate a simplified pre-treatment method for using MALDI-TOF-MS directly on positive blood cultures using BacT/Alert blood culture system, and to test an algorithm combining the result of the initial microscopy with the result suggested by MALDI-TOF-MS. Using the recommended cut-off score of 1.7 the best results were obtained among Gram-negative rods with correct identifications in 91% of Enterobacteriaceae, 83% in aerobic/non-fermentative Gram-negative rods, whereas results were more modest among Gram-positive cocci with correct identifications in 52% of Staphylococci, 54% in Enterococci and only 20% in Streptococci. Combining the results of Gram stain with the top reports by MALDI-TOF-MS, increased the sensitivity from 91% to 93% in the score range from 1.5 to 1.7 and from 48% to 85% in the score range from 1.3 to 1.5. Thus, using this strategy and accepting a cut-off at 1.3 instead of the suggested 1.7, overall sensitivity could be increased from 88.1% to 96.3%. MALDI-TOF-MS is an efficient method for direct routine identification of bacterial isolates in blood culture, especially when combined with the result of the Gram stain.     

Is semiquantitative culture of central vein catheter tips useful in the diagnosis of catheter-associated bacteremia?

Semiquantitative culturing of catheter tips has been used as an index of catheter-related bacteremia. As the sensitivity and predictive values of this test have not been determined, we studied 780 tips from central vein catheters inserted into 440 critically ill patients in an intensive care unit. The results were correlated with clinical data for 30 bacteremic episodes which occurred in these patients, 14 of which were catheter related. When five or more colonies per plate were taken as a positive result, the sensitivity of the method was 92%, and the specificity was 83%. Although the predictive value of a negative result was excellent (99.8%), the predictive value of a positive result was low (8.8%) in our patient population, which had a relatively low incidence of catheter-related bacteremia (2%). We conclude that a semiquantitative culture technique is useful in the diagnosis of bacteremia associated with central vein catheters.     

直视下腹膜透析管置入术腹壁固定与非固定效果观察

目的探讨腹膜透析置管术中行腹壁固定与非固定两种方式的效果差异。方法慢性肾功能衰竭患者38例,均选择腹膜透析作为肾脏替代治疗模式。按腹膜透析置管术式分为腹壁固定组与非固定组,比较不同术式的透析液出入速度及超滤量、腹透管移位发生率。结果两组透析液出入及超滤量无明显差异;但腹壁固定组腹透管移位发生率为零,非固定组腹透管移位发生率为15%,二者相差显著（P〈0.01）。结论采用腹壁固定术可有效减少术后腹膜透析导管移位发生。     

A comprehensive quality assessment program on the autopsy service

Many previous studies have established the value of the autopsy in assessing clinical diagnostic accuracy. None has described, however, the use of the autopsy as an ongoing, prospective audit of clinical and pathologic performance. The authors herein outline the process and report the initial results of a comprehensive quality assessment program on their autopsy service. Particular emphasis was placed on evaluation of the responsiveness of the autopsy to clinical questions and interests. The four parts of the overall program included an epidemiologic survey of causes of death in the authors' patient population, a determination of the clinical significance of autopsy findings, an assessment of clinical factors that may have contributed to death, and a quality control mechanism of the autopsy itself. The process can be adapted to a variety of hospital settings.     

Experiments on clinical observation and judgement in the assessment of depression: profiled videotapes and Judgement Analysis

Variations within and between observer-judges reduce the accuracy of clinical research. Judgement Analysis allows strategies to be developed and applied which reduce variation in judgement. The prediction that the removal of important sources of error variance by this means would reduce the likelihood of committing a Type 2 Error was supported by the application of Judgement Analysis to assessments by 15 psychiatrists of 92 patients in a clinical trial of 2 antidepressive treatments. The statistical significance of differences between the effect of the treatments on the severity of depression was increased, and significant differences appeared earlier. Ten stimulated patient profiles were also converted into narrative case histories, enacted by experienced psychiatrists or psychologists and videotaped. The participants' judgements of the overall severity of the depression were in good agreement with those they had made on the original cases. Videotapes so prepared help training to reduce variation in observation, just as Judgement Analysis can lead to reductions in the variation of judgement.     

Differentiation of <Emphasis Type="Italic">Candida albicans</Emphasis> from non-<Emphasis Type="Italic">albicans</Emphasis> yeast directly from blood cultures by Gram stain morphology

Clusters of pseudohyphae are commonly seen on Gram stain of blood cultures from patients with Candida albicans fungemia. Whether this morphologic feature is useful for differentiating C. albicans from other yeasts has not previously been systematically evaluated. Yeast morphology on Gram stain of blood cultures from consecutive patients with fungemia detected by the Bactec automated blood culture system was prospectively assessed and correlated with the final culture-based yeast identification. The distribution of yeast in 60 consecutive patients with fungemia included Candida spp. (C. albicans 43%, Candida glabrata 28%, Candida parapsilosis 8%, Candida krusei 7%, Candida tropicalis 5%, Candida dubliniensis 2%, and Candida lusitaniae 2%), Rhodotorula mucilaginosa 2%, and Cryptococcus neoformans 3%. Upon analysis of the first positive blood culture bottle per patient, the presence of clustered pseudohyphae on Gram stain had a sensitivity, specificity, positive predictive value, and negative predictive value of 85, 97, 96, and 89%, respectively, for C. albicans. The sensitivity and specificity of aerobic vs Myco/F blood culture bottles were 96 and 95% vs 25 and 100%, p < 0.001, respectively. Inter-rater agreement for ten separate observations among five reviewers was 100%. The presence of pseudohyphae clusters by Gram stain of blood cultures is useful in distinguishing C. albicans from non-albicans yeast. Additional studies are necessary to determine the clinical impact of these findings and their validity with other blood culture systems.     

Andrology: Action of pentoxifylline directly on semen

In the presence of pentoxifylline, spermatozoa can be inducedto increase certain motion characteristics. This drug capabilityhas been used to study the effect when applied directly on semen.An equal volume of pentoxifylline was added to semen, whichwas then incubated for 1 h before processing. Sperm motion wasassessed employing computer-assisted semen analysis. The resultsshowed that pentoxifylline increased curvilinear velocity, straightline velocity and lateral head displacement, the latter effectbeing concentration-dependent over the entire range of concentrationstested (r = 0.93, P < 0.0001). With a high concentrationof pentoxifylline, spermatozoa exhibited characteristics consistentwith hyperactive-like motion. Semen characteristics showed markedinter-individual variation, ranging from 0 to >40% responseto 6 mM pentoxifylline challenge. Some 10% of patients showedlittle or no response to pentoxifylline. The sum of the percentagechanges in curvilinear and straight line velocity, lateral headdisplacement and manual sperm count for each dose group wasused to produce the stimulation index, measuring the overallresponse of spermatozoa to the drug. This stimulation indexshowed that the most effective concentration was 6 mM pentoxifylline,considerably higher than the 3.6 mM pentoxifylline used commonlyfor separated spermatozoa.     

利用生物力学方法评价振动在骨质疏松康复过程中的作用

目的 通过研究基于Micro CT数据的大鼠股骨皮质骨材料性质与力学性能的关系,探讨振动在对抗骨量丢失过程中的生物力学评价方法。方法 Wistar大鼠35只,尾部悬吊建立废用性骨质疏松模型,随机分为间歇振动1、3、5、7 d和持续振动组。实施35 Hz、0.3 g的机械振动,8周后处死,取其左侧股骨行Micro CT扫描,建立皮质骨三维有限元模型,计算获得其表观和组织水平的力学参数。通过主元素分析法从材料分布、间歇振动天数、体积分数中提取主元素。结果 提取出了能够全面反映振动下皮质骨材料性质的3个主元素,并建立起主元素与表观和细观力学参数之间的回归方程。影响皮质骨力学性能的主要因素为材料分布,体积分数与间歇振动天数的影响次之。结论 皮质骨的材料性质能够反映其力学性能的变化,通过材料性质与力学性能的关系可以评估骨强度,为骨质疏松的振动防治及其康复过程的评价提供理论依据。