Starch agar contains high molecular weight starch molecules (soluable starch). When Iodine is added it reacts with starch to produces a dark brown/purple color. A zone of clearing forms around organisms that produce the exoenzyme amylase after addition of iodine. This plate was incubated for ... Read More
Please help me! I am planning to identify this microorganism by API but I can not identify the shape (rod or cocci). This microorganism has positive oxidase. Its colony is red, irregular, flat.
Please teach me. Thanks so much! Nhu Thuy from Vietnam
Kirby-Bauer disk diffusion susceptibility test on coagulase-negative Staphylococcus aureus and E.coli grown on Mueller-Hinton agar with tetracycline (30 µg), cephalothin (30 µg), erythromycin (15 µg), chloramphenicol (30 µg), vancomycin (30 µg), penicillin (10 µg), streptomycin (10 µg), and novo... Read More
Organisms grown in Fluid Thioglycollate Media w/out resazurin dye is a reducing media that uses sodium thioglycollate to chemically combine with dissolved oxygen to deplete the oxygen in the media. All organism except for Neisseria sicca were grown for 48 hours at 37 degrees C. Neisseria sicca i... Read More
Many air travelers are concerned about the risks of catching a disease from other passengers given the long time spent in crowded air cabins. New research shows disease-causing bacteria can linger on surfaces commonly found in airplane cabins for days, even up to a week. Participants discuss ... Read More
This confocal micrograph, taken as part of a synthetic biology project, shows Bacillus subtilis, a Gram-positive, rod-shaped bacterium that is commonly found in soil. Distinct lineages of bacteria expressing different fluorescent proteins were initially mixed randomly on a petri dish. As the bac... Read More
Mannitol Salt Agar (MSA)
•Important Ingredients: Phenol red, mannitol (sugar), 7.5% NaCl
•Differential: between pathogenic S. aureus and S. epidermidis
•Selective: NaCl inhibits non-halophilic organisms. Organism that can grow are halophilic.
•Mannitol Fermentors: fermentation of acid cau... Read More
Unknown organism isolated from a swab taken off the bottom of a shoe. Students were asked to swab something in the classroom. One swab was done on the bottom of a shoe and incubated on a TSA plate for 48 hrs at 37 degree’s C. The organism was difficult to scrape so a small chunk of the organis... Read More
Bacitracin test done on a lawn of Streptococcus pyogenes grown on blood agar. The zone of inhibition around the bacitracin disc, approx 14mm measuring the entire length of the zone, indicates sensitivity. The zone of inhibition is red because the red blood cells did not lyse. Grown for 24 hr... Read More
A streak plate of Strep pyogenes on blood agar, stock culture used for class, was kept at room temp for 1 month. Before disposal a contaminant, presumably environmental, was seen on the plate. The pigment was opaque tan/yellow and with a mucoid surface. Lobate marigins with raised irregular-rh... Read More
Three organisms inoculated in TSB to look at tube morphology. From left to right:
Staphylococcus aureus: flocculent growth/turbid, growth throughout the tube.
Mycobacterium smegmatis: pellicle, growth at the top of the tube. M. smegmatis tends to stick to the tube and grow up the side.
Ba... Read More
Germaphobes, maybe you're on to something.
Sickness-causing bacteria and viruses can lurk on surfaces long after they're expelled in an infected person's sneeze or snot. Some can even stay on a surface for months, given the right conditions. While the ability of these microorganisms to actual... Read More
It's Friday and I can finally enjoy the beach! So I thought it would be nice to reflect my excitement at work growing this happy Listeria monocytogenes ;) Read More
A colorized electron microscope image captures delicate chains of streptococcus in a laboratory sample. Though some strep infections can be deadly, many strains are harmless—among the thousands of benign beings that make their home in our bodies.
Photograph by Martin Oeggerli, with support fr... Read More
Bioluminescent art blends science and creativity to create images that can only be seen in the dark. What do you get when you add a chemical engineer, a graphic designer and a research scientist? Beautiful art. In a wondrous combination of nature and design, bioluminescent art involves using nat... Read More
Gram stain done on S. pyogenes showing the characteristic long G+ streptococcus chains. Culture grown on blood agar for 48 hrs at 37 degree’s C. Read More
Artist Sonja Bäumel explores the skin microbiome in her project Cartography of the Human Body. Bacteria isolated from Bäumel’s skin were characterized and grown individually, then used to reconstruct an artificial microbiome with many layers of differently-colored species. Giant petri dishes gre... Read More
It is a well recognized uncommon cause of skin and nail infection of the hands and feet . Unlike Dermatophytosis these mould infections are not contagious. There are few reports of invasive infection caused by N. dimidiatum; most infections occurred in immunocompromised hosts. Arthrospores are ... Read More
Line inoculation of Micrococcus luteus on a TSA slant showing Filiform, uniform growth, along the margin. Culture was grown for 3 days at 37 degrees, M. luteus usually takes 3+ days for good growth. Read More
Nocardia asteroides isolation from blood specimen. On culture, chalky white colonies were seen on blood agar. Image courtesy MicrobeWorld user Kyriakos Zaragkoulias, Specialty Registrar (StR) in Medical Microbiology at General Hospital of Thessaloniki “G. Papanikolaou”, Greece.