Art and Science of Laboratory Medicine

Art and Science of Laboratory Medicine

Thursday, March 17, 2016

Urine Test Can Measure Specific Compounds from Food Consumed

Can we say goodbye to unreliable food diaries and diet recall in exchange for a urine test that will better aid researchers in figuring out what foods might help prevent cancer?
Georgetown researchers have developed a method that can quickly evaluate specific food compounds in human urine.

The new urine test looks for specific members of the isothiocyanates (ITCs) family (among other compounds), found in cruciferous vegetables. Animal and cell studies have shown that different types of ITCs have varying anticancer properties and potency, suggesting they are not equal
in protecting against cancer, Dyba says. “We developed our test because there has been no way to find out which specific ITCs works best,” he says.

For their study, the researchers focused on cruciferous vegetables, which showed a protective benefit against lung cancer in a study of more than 63,000 people who participated in the National Institutes of Health’s Singapore Chinese Health Study. Cruciferous vegetables, a major food in the Asian diet, include cabbage, Brussels sprouts, broccoli, cauliflower, bok choy and watercress, among others.

Read more:
Urine Test Can Measure Specific Compounds from Food Consumed 

Source: News wice

Monday, March 14, 2016

Quality Improvement in the Coagulation Laboratory

Reducing the Number of Insufficient Blood Draw Specimens for Coagulation Testing

To report the efforts of our laboratory to reduce quantity-not-sufficient (QNS) specimens via several methods and to directly measure the effect of expired collection tubes on the amount of blood that can be drawn.

A study tracked the number of QNS venous-blood specimens per month received by our coagulation laboratory from March 2008 to December 2012. Interventions involved communications that informed nurses and phlebotomists how to avoid drawing QNS specimens and floor sweeps, in which laboratory staff searched for and removed expired vacuum-based blood-collection tubes (VBCTs) from inpatient hospital floors. Also, we assessed 11 healthy donors to determine the amount of blood that could be drawn into expired VBCTs.

During the study period, the rate of QNS specimens dropped from a mean of 0.7% to 0.3%. In expired VBCTs collected from healthy donors, we observed a statistically significant difference in the amount of blood drawn into nonexpired vs expired VBCTs (P <.001). Also, there was a negative relationship between the number of months that the VBCT had been expired and the amount of blood that could be drawn into the VBCTs (P <.001). For every month that VBCTs were expired, the amount of blood drawn decreased by approximately 1.8 mm (0.1 mL), using linear regression analysis.

This study strongly suggests that expired VBCTs consistently and progressively yield QNS specimens. Methods to reduce blood draws from expired VBCTs may include communications promoting proper blood draw technique, floor sweeps to remove expired VBCTs, and improved inventory management.

Read more:
Quality Improvement in the Coagulation Laboratory

Source: Medscape

Sunday, March 13, 2016

Scientists identify a virus and two bacteria that could be causing Alzheimer's

An international group of 31 Alzheimer's researchers has published an editorial urging the science world to change its focus when it comes to Alzheimer's disease. The message is clear - after a decade of failed attempts to treat and prevent the disease, it's time to reassess the evidence that Alzheimer's could be spread by microbes.

Study says that the first microbes we should investigate are the herpes simplex virus type 1 (HSV1), the chlamydia bacteria, and spirochaetes.

So how could viruses and bacteria trigger Alzheimer's disease? Well, we still don't really know, which is one of the reasons research has stalled in this area, but the herpes virus is already known to damage the nervous system, and microbial infections are known to inflammation around the body, which is a characteristic of Alzheimer's disease.

Of course, the issue is not as clear-cut as the editorial makes it out to be - if it was, we'd already know how to fix the disease. And most importantly, experts are urging people not to freak out about the implication that Alzheimer's could be 'caught'.

Read more:
Scientists identify a virus and two bacteria that could be causing Alzheimer's

Source: ScienceAlert

List of culture media used in microbiology

Many types of bacterial growth media are used to culture (grow) microbes in the laboratory. Here's a summary of defined, complex, selective and differential media.

Read more:
Microbiology notes

·   Alkaline Peptone Water
Enrichment media for Vibrio cholerae
·   Alkaline Salt Transport Medium
·   Taurocholate Peptone Transport Medium
Transport media for diarrheal diseases suspected of being caused by V. cholerae
·   Anaerobic Media
Liquid media by addition of
·     Glucose (0.5 % to 1 %)
·     Ascorbic Acid (0.1 %)
·     Cysteine (0.1 %)
·     Sodium Merceptoacetate (0.1 %)
·     Thioglycollate (0.1 %)
·     Particles of cooked meat broth
·   Bile Salt Agar
·   Thiosulphate Citrate Bile Salts-Sucrose Agar (TCBS)
·   Monsur’s Tellurite Taurocholate Gelatin Agar
Selective media for V. cholerae
·   Bile Esculin Agar (Contains 40% Bile)
Selective media for Enterococcus species (Black coloration of the medium)
·   Blood Agar
·     Enriched media (Supports the growth of fastidious organisms, e.g. Streptococcus)
·     Indicator media to show hemolytic properties of certain organisms (Staphylococcus aureus: β-Hemolytic; Streptococcus pneumonia and S viridans: α-Hemolytic; Enterococcus: Non-Hemolytic)

·   Bordet-Gengou Agar
·   Charcoal Blood Agar
·   Regan-Lowe Medium (Charcoal Agar with blood, cephalexin and Amphotericin B)
Isolation of Bordetella pertussis
·   Brain Heart Infusion Broth
Used in blood culture bottles (both adult and pediatric patients)
·   Buffered Charcoal Yeast Agar (BCYA)
·   Feeley Gorman Agar
Specialized media for isolation of Legionella
·   Campylobacter Thioglycollate Broth
Selective holding media for recovery of Campylobacter species
·   Castaneda Medium
Biphasic medium for the isolation of Brucella
·   Cefoxitin Cycloserine Fructose Agar (CCFA)
·   Cefoxitin Cycloserine Egg-Yolk Agar (CCEY)
Selective media for isolation of Clostridium difficile form suspected cases of pseudomembranous colitis/antibiotic-associated diaeehea
·   Cefsulodin-Irgasan-Novobiocin medium (CIN Medium)
Selective media for Yersinia (and may be used for Aeromonas also)
·   Columbia-Colistin Nalidixic Acid agar (CNA Agar)
Selective media for the isolation of Gram-positive cocci
·   Cooked meat broth
·   Nutrient agar slopes
·   Semisolid nutrient agar stabs
·   Heated blood agar slopes
In general, used for preservation and storage of bacterial cultures
·   Crystal violet blood agar
Selective media for Streptococcus pyogenes
·   Cysteine Lactose Electrolyte Decient Media (CLED Media)
Most commonly used media for culturing urine samples
·   Egg Saline Medium
Preservation of cultures of Gram-negative bacilli
·   Egg Yolk Agar
Detection of lipase and lecithinase activity of Clostridium species
·   Ellner’s Medium
·   Medium of Duncan and Strong
·   Medium of Phillips
·   Alkaline Egg Medium
Specialized media to induce sporulation in Clostridium
·   Fildes Blood-Digest Agar and Broth
·   Levinthal’s Agar
Enriched media for recovery of Haemophilus inuenzae
·   Firm Agar (4% to 6% Agar)
Prevents swarming of Proteus mirabilis, P. vulgaris and Clostridium tetani
·   Fletcher’s Agar
·   Ellinghausen and McCullough Medium
·   Ellinghausen-McCullough-Johnson-Harris (EMJH) Media
Solid media for isolation of Leptospira
·   Glycerol Saline Transport Medium
Transport stool specimen for typhoid bacilli
·   Heated Blood Agar/Chocolate Agar
Growth of fastidious organisms (E.g. Hemophilus inuenzae, Neisseria gonorrhoeae and S. pneumoniae
·   Hoyle’s Tellurite Lysed Blood Agar
·   Tinsdale Medium
Selective media for isolation of Corynebacterium from throat swabs
·   Loeffler Serum Slope
Stimulation of metachromatic granules in Corynebacterium diphtheriae
·   Lowenstein-Jensen Medium
·   Middlebrook Media
Selective media for isolation of Mycobacterium tuberculosis from sputum and other samples
·   MacConkey Agar
Differential media for Enterobacteriacaeae (i.e., lactose fermenting and non-lactose fermenting)
·   MacConkey Bile Salt Lactose Agar
·   Brilliant MacConkey Agar
·   Leifson’s Deoxycholate-Citrate Agar (DCA)
·   Wilson and Blair’s Brilliant Green Bismuth- Sulphite Agar (BBSA)
·   Taylor’s Xylose Lysine Deoxycholate Agar (XLD)
·   Hektoen Enteric Agar
·   SalmonellaShigella Agar
Differential and media for isolation of Salmonella and Shigella from stool specimens
·   Mannitol Salt Agar
Selective and indicator media for S. aureus
·   Modied Barbour Stoenner Kelly medium (BSK)
Specialized media for Borrelia burgdorferi
·   Modified Korthoff’s Medium
Liquid media for isolation of Leptospira
·   Modied New York City Medium (contains colistin, lincomycin, trimethoprim, amphotericin B)
Selective media for Neisseria gonorrhoeae
·   Mueller-Hinton Agar
Performing antimicrobial susceptibility for bacteria
·   Nutrient Agar (1% to 2% Agar)
Basal media in microbiology
Supports the growth of all non-fastidious organisms
·   Non-Nutrient Agar
Cultivation of parasites (e.g., Acanthamoeba)
·   Peptone Water
·     Basal media for preparation for carbohydrate fermentation media
·     To ascertain whether a bacteria is motile or non-motile
·     Basis for Indole test

·   Phenol-Red Egg Yolk Polymyxin Agar
Selective media for isolation of Bacillus cereus from food, feces, and vomitus
·   Pike’s Media
Preservation of S. pyogenes, pneumococci, and Hemophilus inuenzae in nose and throat swabs
·   Polymyxin B-lysozyme-EDTA-Thallous Acetate (PLET)
Selective media for isolation of Bacillus anthracis from soil and other medium materials containing numerous spore formers of other species
·   Polymyxin B, Neomycin, Fusidic Acid Media (PNF)
Selective media for S. pyogenes (or β-hemolytic Streptococcus)
·   PPLO Medium (Contains Sterol)
Specialized media for Mycoplasma pneumoniae
·   Pre-Reduced Anaerobically Sterilized (PRAS) Media
Commercially available media for anaerobic organisms
·   Proteose Peptone-Yeast Extraction Broth
Media for carrying out biochemical tests for anaerobes
·   Requirements of X and V Factors
Isolation of Haemophilus influenzae
·   Roswell Park Memorial Institute (RPMI) 1640 Medium
Cultivation of malarial parasites (i.e., Plasmodium)
·   Robertson Cooked Meat Broth (RCMB)
·      Growth of anaerobes (e.g., Clostridium)
·      Maintaining stock cultures of anaerobic organisms
·   Salt-Cooked Meat Broth (Cooked Meat Broth with 10% NaCl)
Enrichment media for isolation of S. aureus from heavily contaminated materials
·   Semisolid Agar (0.05% to 0.1% Agar)
Prevents convection current and allows the growth of anaerobic and micro-aerophilic organisms
·   Skirrow’s Campylobacter Medium (contains polymixin B, trimethoprim, vancomycin)
·   Preston Campylobacter Medium (contains polymixin B, rifampicin, trimethoprim)
·   Campy Blood Agar
·   CVA Medium (contains cefoperazone, vancomycin, amphotericin)
Selective media for Campylobacter jejuni
·   Smith-Noguchi Medium
Cultivation of nonpathogenic treponemes (e.g., Reiter strain of Treponema phagedenis)
·   Sorbitol MacConkey Agar
Isolation of verocytotoxin-producing (enterohemorrhagic) E. coli of 0157 type (as it fails to ferment D-sorbitol)
·   Stuart Transport Media
·   Amies Transport Media
Maintaining the viability of gonococci on swabs during transportation
·   Tetrathionate Broth
·   Gram-Negative Broth
·   Selenite-F Broth
Enrichment media for isolation of Shigella and Salmonella from stool samples
·   Thayer-Martin Medium (contains vancomycin, colistin, nystatin)
Selective media for Neisseria gonorrhoeae
·   Thioglycollate Broth
·   Trypticase Soy Broth
All purpose enrichment broth for anaerobes, aerobes, micro-aerophilic, and fastidious organisms
·   Todd Hewitt Broth with Antibiotics
Selective and enrichment for Streptococccus agalactiae in female genital specimens
·   Triple Sugar Iron Agar (TSI) Medium
Differentiation of various members of Enterobacteriaceae
·   Wilkins-Chalgren Agar
Performing antimicrobial susceptibility of anaerobic bacteria

Source:Microbiology notes

Follow "Art and Science of Laboratory Medicine " on: