Early detection of Leishmania promastigotes in dog bone marrow cultures by acridine orange stain

An acridine orange staining technique was evaluated in comparison with other well-known methods for the laboratory diagnosis of leishmaniasis. A higher number of promastigotes was found in Novy-MacNeal-Nicolle (NNN) cultures inoculated with canine bone marrow, when culture samples were stained with acridine orange vital stain, compared with those detected using either Giemsa staining or unstained wet mount examination. Based on our data the acridine orange stain is a useful and timely technique in reflecting the true numbers of microorganisms present in a culture and also enhances the visualization of the parasites. The present results warrant further studies with human samples from suspected leishmaniasis patients.     

Evaluation of the Coral UTI Screen system for rapid automated screening of significant bacteriuria in a regional centralized laboratory

An evaluation of the Coral UTI screen system (Coral Biotechnology, San Diego, CA) compared to urinalysis/urine culture was done to assess its performance for rapidly screening a high volume of urine samples for significant bacteriuria in a regional central microbiology laboratory. A total of 1094 urine samples from ambulatory patients were evaluated. 670 (61.2%) urine samples were negative or positive [178 (16.3%)] by both methods. 217 (19.8%) other samples were UTI screen positive but had either no growth or no uropathogens on culture; 9 of these samples were possibly false negative by culture because of the presence of pyuria, indicating the presence of either a urinary tract infection or another inflammatory process. Another 29 (2.7%) samples had false negative screens because the urine culture was positive, but only 5 of these patients were treated with antibiotics after urine specimen collection. Overall, the Coral UTI screen has a sensitivity of 86.0%, a specificity of 75.5% and a positive and negative predictive value of 45.0% and 95.9% respectively. Routine use of the UTI screen would allow same day reporting of 65% of all urine culture results without having to proceed to culture.     

Rapid screening and microbiologic processing of pediatric urine specimens

Urinary nitrite and leukocyte esterase dipstick tests were evaluated as rapid screening procedures to select probable culture-positive urines for direct identification (AutoMicrobic System urine cards) and modified Kirby-Bauer susceptibility testing. Approximately 73% of significant culture-positive (greater than 10(5) organisms per milliliter, pure culture) urine specimens could be selected by nitrite testing alone with very high specificity (approximately 99%). The leukocyte esterase test detected 85% of culture-positive urines when used alone and approximately 91% when used in combination with nitrite testing (if either test was positive it was considered a positive screening); however, the esterase test was significantly less specific for bacteriuria than the nitrite test. Based on these results, the nitrite test was selected for use as the screening test. Rapid, direct identification and susceptibility tests on screen-positive urines showed 97% correlation with standard testing methods. Significant positive urines processed in this manner could be reported with quantitation, identification, and susceptibility results within 24 hr.     

Use of the Becton-Dickinson urine culture tube with the Abbott MS-2 urine screening system

Urine specimens were obtained from 312 obstetric outpatients by sterile midstream technique and aliquots placed in both Becton-Dickinson urine culture tubes and sterile conventional tubes. Quantitative cultures were made from each tube, and each tube was screened for bacteria with the Abbott MS-2 urine screening system. The time required to detect bacteriuria was recorded for both specimens. Isolates from specimens containing ≥50,000/ml gram-positive cocci or ≥100,000/ml gram-negative bacilli were identified and antimicrobial susceptibility tests performed. Delayed (24 hr) quantitative cultures were done from Becton-Dickinson tubes. By these criteria, 124 urine specimens were positive in both conventional and Becton-Dickinson tubes. $\text{Escherichia coli}$ ($\text{n}\text{= 72}$, $\text{Klebsiella pneumoniae}$ ($\text{n}\text{= 20}$), $\text{Enterobacter cloacae}$ ($\text{n}\text{= 8}$), $\text{Proteus mirabilis}$ ($\text{n}\text{= 4}$), group B streptococcus ($\text{n}\text{= 12}$), and enterococcus ($\text{n}\text{= 8}$) were isolated. Time for detection of positive urine samples was similar in both types of tubes. Delayed cultures had significant numbers of false-positive results. Antimicrobial susceptibility results did not appear to be influenced greatly by Becton-Dickinson tube transport. The MS-2 cannot adequatey discriminate cultures containing <50,000 colony-forming units/ml of urine. The Becton-Dickinson tube appears to be compatible for use with the MS-2 for purposes of screening for bacteriuria.     

Rapid determination of minimum inhibitory concentrations of antimicrobial agents by the Autobac method: a collaborative study.

Four laboratories collaborated in an evaluation of the Autobac minimum inhibitory concentration (MIC) test system. The MICs of ranges of MICs determined in this system were compared with the MICs obtained with a microtube modification of the International Collaborative Study broth dilution technique. A total of 1,260 strains, mostly recent clinical isolates and including multiresistant strains, were tested by the four laboratories against 10 antibiotics; 9,360 separate MIC determinations were made. There was an overall agreement of approximately 95% between the two methods. Levels of agreement below 80% were obtained with only 4 of the 104 antibiotic-species pairs. In only one of the four major organism groups (staphylococci and penicillin G) was agreement less than 85%. There was a symmetrical distribution of MIC differences between the two methods. Tests with 56 selected strains were performed in each of four laboratories in an inter- and intra-laboratory reproducibility study. Both methods showed a standard deviation (both inter- and intra-laboratory) of one-half of a twofold dilution step. The Autobac method was actually less variable than the reference method and had equivalent reproducibility. This was particularly true when the Autobac system was operated so that the results generated permitted calculations of MICs via regression analysis.     

精子染色质扩散试验及吖啶橙染色试验检测精子DNA完整性研究

目的 探讨精子染色质扩散(sperm chromatin dispersion,SCD)试验及吖啶橙染色(AO)试验检测精子DNA完整性的应用价值.方法 对32名已生育的成年男性健康对照者和27例特发性少精子症(idiopathic oligozoospermia,IO)患者同时进行SCD试验和AO试验,对检测结果 进行分析.在SCD试验中,DNA完整性正常精子的DNA扩散形成大晕环或中晕环,而受损伤产生DNA碎片的精子不形成或形成很小的晕环.用AO试验检测,正常精子DNA为双链,染成绿色,不成熟或损伤精子DNA为单链.染成红色、橙色或黄色.结果 SCD试验检测10患者的大晕环、中晕环、小晕环和无晕环精子百分率分别为(49.9±13.8)%、(11.5±5.4)%、(11.9±6.1)%和(26.7±10.0)%,健康对照组分别为(73.2±6.2)%、(14.7±6.3)%、(6.8±2.9)%及(5.3±2.2)%,2组比较,差异有统计学意义(t=8.576,P＜0.O1;t=2.083,P＜0.05;t=4.284,P＜0.01;t=11.823,P＜0.01);IO患者的DNA损伤精子的百分率为(38.6±12.1)%,健康对照组为(12.1±5.2)%,2组比较差异有统计学意义(t=11.995,P＜0.01).AO试验检测IO患者的单链DNA精子百分率为(45.5±13.8)%,健康对照组为(39.8±13.3)%,差异无统计学意义(t=1.626,P＞0.05).结论 精子DNA完整性异常可导致男性不育.SCD试验是一种有效的精子DNA完整性检测方法 .     

Improved urine screening using a combination of leukocyte esterase and the Lumac system

Three rapid urine screening tests, leukocyte esterase, nitrite, and the Lumac System for detection of bacterial ATP, were evaluated alone and in combination to determine their utility in screening urine specimens from male patients for bacteruria. The combination of leukocyte esterase and Lumac testing resulted in significant improvement in the sensitivity of urine screening over each test individually and the combination of leukocyte esterase and nitrite. The leukocyte esterase/Lumac combination detected 98% of those specimens with greater than or equal to 10(5) CFU/ml and had a negative predictive value of 99%. The results obtained from this type of testing can be used with confidence to minimize the number of urine specimens cultured and to provide rapid reporting of negative results.     

Comparison of AMS-Vitek, MicroScan, and Autobac Series II for the identification of gram-negative bacilli

Identification of Gram-negative bacilli by AMS-Vitek, MicroScan, and Autobac Series II was evaluated with 434 clinical isolates comprising glucose fermenters and glucose nonfermenters. The organisms were tested in each of the three systems (the AMS Vitek GNI card, the MicroScan Combo Plus Panel, and the Autobac 18 chamber cuvette). API 20E was used as the primary reference system. MicroScan and Vitek correctly identified 96.1% and 95.6% of the organisms, respectively. The Autobac Series II identified 82.3% of the organisms correctly. Results with MicroScan, Vitek, and Autobac were available in 24-48 hours, 4-18 hours, and 3-8 hours, respectively.     

Evaluation of dipstick tests and reflectance meter for screening for bacteriuria in elderly patients.

When screening for bacteriuria in 615 elderly people was compared to standard methods of bacterial culture, the Ames Multistix 10 dipstick was more effective than the BM Test 7. Tests for nitrite and leucocyte esterase on the Multistix 10 had a higher sensitivity and specificity than tests for blood and protein only. Using a reflectance meter increased the sensitivity of the Multistix 10 to 80.6%. Of five common urinary symptoms only incontinence was significantly more frequent in patients with bacteriuria.     

Deletions in Klebsiella pneumoniae R plasmids induced by growth in the presence of acridine orange at high temperature.

The generation in vivo of plasmids deleted at specific sites in strains of Klebsiella pneumoniae containing R plasmids, by treatment with high concentrations of acridine orange (1.2 mg/ml) at 42 degrees C are reported. These deletions seem to be site specific because loss of specific restriction fragments after digestion with restriction enzymes was demonstrated.     

Rapid carrier screening for beta-thalassemia by single-step allele-specific PCR and detection

OBJECTIVES: This study aimed to evaluate a rapid molecular carrier screening strategy for beta-thalassemia. DESIGN AND METHODS: Allele-specific PCR was combined with amplicon detection by dissociation curve analysis of SYBR Green I fluorescence in a single step. RESULTS: The presence of a particular mutation results in the amplification of a mutation-specific product and the dissociation temperature of each amplicon was highly reproducible. CONCLUSIONS: Homogeneous allele-specific PCR amplification and detection of multiple beta-globin mutations can serve as a rapid and inexpensive carrier screening tool.     

Photodynamic inactivation of bladder cancer cells (MGH-U1) sensitized with acridine orange and irradiated by argon laser

Photodynamic inactivation of bladder cancer cells (MGH-U1) was investigated in order to apply laser therapy to the treatment of bladder cancer. After stained with acridine orange (AO), the material cells were irradiated with argon laser. After 24 hr incubation the survival was counted with a hemocytometer. The number of stained cells showed a less than 5% decrease and the number of irradiated (for 15 min) unstained cells showed no decrease compared with untreated cells. Participation of singlet oxygen process in inactivation of MGH-U1 cells was confirmed by the use of D2O and NaN3. The result shows that argon laser at the low intensity and with short irradiation time has a sufficient cytocydal effect, suggesting the usefulness of photodynamic inactivation of argon laser with topical use of acridine orange in the treatment of bladder cancer.     

Precise diagnosis of infection in burn wound biopsy specimens. Combination of histologic technique, acridine orange staining, and culture

This study developed a rapid manual histologic technique on burn wound biopsy specimens for an early diagnosis of infection. A total of 86 biopsy specimens were processed using this rapid manual method, acridine orange fluorescent staining for the detection of microorganisms, and a quantitative culture for the identification and counting of bacteria in adjacent homogenized biopsy specimens. Use of these three techniques has shown their complementarity for the evaluation of sepsis in burn wound patients. The histologic study allowed a classification of the depth of bacterial involvement 4 hours after specimen collection, whereas the acridine orange fluorescent staining was useful for quantitative evaluation of infection in the same delay. Thus a rapid therapeutic decision can be made while waiting for the results of quantitative culture and sensitivity tests, which require 24 to 48 hours. We propose routine monitoring of burned patients consisting of these three tests performed simultaneously on each biopsy specimen.