5554503 Sample processing method for mycobacterium tuberculosis

A disadvantage of nonradioactive microsphere techniques is that the processing of samples is time-consuming and complex. We developed and validated a simplified processing method for the fluorescent microsphere (FM) technique. In seven anesthetized dogs with coronary artery stenosis up to six different FM and five different radioactivity labeled microspheres (RM) were injected. Two FM and two RM labels were injected simultaneously to enable inter- and intramethod comparison. After gamma-counting samples of blood, myocardium (n = 168), and other organs (n = 59) were digested in test tubes with 2 N ethanolic KOH (60 degrees C, 48 h), microspheres were sedimented by centrifugation, dye was extracted in the same tube, and fluorescence was measured. With this processing method, recovery of FM was approximately 100%. Good correlations for inter- and intramethod comparisons were found [r = 0.985 +/- 0.01 (mean +/- SD)]. The lower intermethod correlation for blue microspheres (r = 0.958) indicates that the use of this label is less desirable. RM and FM endocardial-to-epicardial blood flow ratios correlated well (r = 0.974). With this one-vessel centrifugal sedimentation method and at least five fluorescently labeled microspheres, blood flow can be reliably measured in various organs, including ischemic myocardium.

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Fenitrothion and esfenvalerate stability during corn and wheat sample processing

Scientia Agricola ◽

10.1590/s0103-90162008000200008 ◽

2008 ◽

Vol 65 (2) ◽

pp. 157-160

Author(s):

Javier Alberto Vásquez-Castro ◽

Gilberto Casadei de Baptista ◽

Luiz Roberto Pimentel Trevizan ◽

Casimiro Dias Gadanha Junior

Keyword(s):

Gas Chromatography ◽

Large Scale ◽

Processing Method ◽

Stored Grain ◽

Sample Processing ◽

Wheat Sample ◽

Dry Ice ◽

Insecticide Residues ◽

Stored Grains ◽

The Stability

The presence of insecticide residues in cereals represents a risk for the consumer, because these substances are used in large scale to protect stored grains from the attack of pests. The effects of three processing methods for corn and wheat samples on the stability of stored-grain protective insecticides were here evaluated. Fenitrothion and esfenvalerate were applied so as to produce theoretical concentrations of 10 and 0.5 mg kg-1, respectively. Two hours after treatment, the grains were processed and deposition was analyzed by gas chromatography. Grain species did not influence insecticide stability. This stability was only dependent upon the processing method and insecticide type. Grains processed together with dry ice provided the greatest percentage of recovery for both insecticides. Regardless of the processing method, more esfenvalerate than fenitrothion was recovered, thus demonstrating the greater stability of the pyrethroid during this operation.

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The Simple One-Step (SOS) stool processing method for use with the Xpert MTB/RIF assay for a child-friendly diagnosis of tuberculosis closer to the point-of-care

Journal of Clinical Microbiology ◽

10.1128/jcm.00406-21 ◽

2021 ◽

Author(s):

Petra de Haas ◽

Bazezew Yenew ◽

Endale Mengesha ◽

Andrii Slyzkyi ◽

Zewdu Gashu ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Addis Ababa ◽

Point Of Care ◽

Processing Method ◽

One Step ◽

Stool Samples ◽

Gravity Sedimentation ◽

Child Friendly ◽

Xpert Assay ◽

Proof Of Principle

Young children cannot easily produce sputum for diagnosis of pulmonary tuberculosis. Alternatively, Mycobacterium tuberculosis complex (MTB) bacilli can be detected in stool by using the Xpert MTB/RIF (Ultra) assay (Xpert). Published stool processing methods contain somewhat complex procedures and additional supplies. The aim of this study was to develop a simple one step (SOS) stool processing method, based on gravity sedimentation only, similar to sputum Xpert testing for the detection of MTB in stool. We first assessed if the SOS stool method could provide valid Xpert results without the need of bead-beating, dilution and filtration steps. We concluded that this was the case and, subsequently, validated the SOS stool method by testing spiked stool samples. By using the SOS stool method, of the 29 spiked samples, 27 gave valid Xpert results and MTB was recovered from all 27. The proof of principle of the SOS stool method was demonstrated in a routine setting in Addis Ababa, Ethiopia. Nine of 123 children with presumptive TB were MTB positive on nasogastric aspirate (NGA), and seven (77.8%) of these also had an MTB positive Xpert result on stool. Additionally, MTB was detected in the stool but not on the NGA of two children. The SOS stool processing method makes use of the standard Xpert assay kit, without the need for additional supplies or equipment. The method can potentially be rolled out to any Xpert site, bringing a bacteriologically confirmed diagnosis of TB in children closer to the point of care.

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Comparison of Sample Preparation Methods for Recovering Salmonella from Raw Fruits, Vegetables, and Herbs

Journal of Food Protection ◽

10.4315/0362-028x-64.10.1459 ◽

2001 ◽

Vol 64 (10) ◽

pp. 1459-1465 ◽

Cited By ~ 40

Author(s):

ANDREA B. BURNETT ◽

LARRY R. BEUCHAT

Keyword(s):

Sample Preparation ◽

Pathogenic Bacteria ◽

Preparation Method ◽

Morphological Characteristics ◽

Processing Method ◽

Sample Processing ◽

Processing Methods ◽

Preparation Methods ◽

Wide Range ◽

The Mean

Methods for preparing raw fruits, vegetables, and herbs for enrichment or direct plating to determine the presence and populations of pathogenic bacteria vary greatly. A study was done to compare three sample processing methods (washing in 0.1% peptone, stomaching, and homogenizing) for their influence on recovery of Salmonella inoculated onto 26 types of raw produce. The mean numbers of Salmonella recovered from 10 fruits, 11 vegetables, and 5 herbs using all three processing methods were 7.17, 7.40, and 7.27 log10 CFU/sample, respectively. Considering all 26 types of produce and all processing methods, the number of Salmonella recovered ranged from 7.24 to 7.29 log10 CFU/sample, with no significant differences attributable to a particular sample processing method. Mean percent recoveries of Salmonella from washed, stomached, and homogenized produce were 39.4, 44.7, and 42.4%, respectively. Mean percent recoveries from fruits, vegetables, and herbs, regardless of sample preparation method, were 41.7, 50.1, and 25.9%, respectively. The number of Salmonella recovered from stomached and homogenized produce, but not washed produce, with pH ≤ 4.53 was significantly less than the number recovered from produce with pH from 5.53 to 5.99, suggesting that the acidic environment in stomachates and homogenates was lethal to a portion of Salmonella. Reduced percent recoveries from herbs (pH 5.94 to 6.34) is attributed, in part, to antimicrobials released from plant cells during sample preparation. Overall, the type of processing method did not substantially affect the number of Salmonella recovered from the 26 types of raw produce representing a wide range of structural and morphological characteristics, composition, and pH. The influence of sample size, diluent composition, and processing time on efficiency of recovery of Salmonella and other pathogens needs to be evaluated before a method(s) for processing samples of raw produce can be recommended.

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