Colony Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Colony and links to relevant pages within the course.
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| Which of the following is the proper designation for the pluripotential stem cell that is a precursor for both myeloid and lymphoid cell lines: | View Page |
| The indole test may be used to differentiate members of which of the following species: | View Page |
| Match the description with the appropriate illustration of colony elevations: | View Page |
| Match the illustrations with the corresponding description of colony edges: | View Page |
| The patient was admitted to the hospital. The sputum specimen was inoculated to sheep blood agar. Based on the colony morphology seen in the accompanying photograph, the most likely identification is: | View Page |
| Colony Morphology The growth observed on the anaerobic blood agar plate after 48 hours incubation (see upper photograph), revealed a spreading colony. The spreading nature of the colony is better observed in the close-in photograph (lower). No growth was observed on subcultures incubated aerobically indicating that this isolate is truly an anaerobe (although aerotolerance studies would be needed for confirmation). The spreading nature of the colony and the lack of hemolysis are highly suggestive of Clostridium septicum. However, biochemical confirmation is necessary. | View Page |
| The bacterial cells shown in the photograph were observed in a smear prepared from the colony shown before. Which of the following tests will help to affirm the identification of Staphylococcus aureus? | View Page |
| Illustrated in the upper photograph are tiny pinpoint 24-hour colonies recovered from one of the splenic abscesses. The wide zones of beta hemolysis are better seen in the close-in view of the 36 hour culture shown in the lower photograph.
Streptococcus milleri (anginosus) can be suspected if one of the following odors is detected: | View Page |
| Shown in the photograph is a close-in view of the colony growth after 48 hours incubation. Possible presumptive identifications suggested by the colonies observed include: | View Page |
| Colony Morphology Photograph of the surface of blood agar after 24 hours incubation at 35C in 10% CO2, on which are growing tiny, translucent, gray colonies surrounded by a narrow zone of "soft" beta hemolysis.There was no growth on the MacConkey plate. | View Page |
| Shown in the photograph are three tubes-(1) motility agar (note subsurface flare--see arrows); (2) esculin hydrolysis (+), and (3) VP (+). The reactions illustrated here are sufficient to rule out Erysipelothrix rhusiopathiae. | View Page |
| Illustrated in this photograph is a "green lawn" colony of Gliocladium species. The other hyaline mold that produces this type of colony is: | View Page |
| A dull white fungus, turning mouse gray on maturity, was recovered from material aspirated from a bone cyst in the upper femur. Based on the microscopic appearance as seen in a lactophenol blue mount of a portion of the colony, the most likely identification is: | View Page |
| Match each hyaline mold from the drop-down list to its corresponding colony and microscopic description. The mold colonies are illustrated in the image on the right. | View Page |
| Match each hyaline mold from the drop-down list to its corresponding microscopic and colony description. The microscopic appearance of the molds are illustrated in the image on the right. | View Page |
| Match each hyaline mold from the drop-down list to its corresponding colony and microscopic description. The mold colonies are illustrated in the image on the right. | View Page |
| Match the name of each fungal species listed with its most likely corresponding morphologic features. | View Page |
| The infrequently encountered mold that is represented by the photomicrograph begins as a gray-white colony that blackens with maturity as the hyphae become darkened and single, globose, black conidia are produced. This fungus can be identified as: | View Page |
| Of the following dematiaceous fungi, the black, suede-like colony illustrated here, reaching no larger than the size of a dime after 7 days incubation, most likely can be identified as: | View Page |
| The dematiaceous colony illustrated here grew to a diameter of 3 - 4 cm in 5 days. The dematiaceous fungus that can be ruled out is: | View Page |
| The black yeast colony illustrated in this photograph may represent any of the following dematiaceous molds except: | View Page |
| The dematiaceous conidium illustrated in this photomicrograph was obtained from a tiny portion of dark colony that grew to maturity in six days. Spores incubated in a saline mount for four hours developed germ tubes from both terminal cells. The features observed confirm the identification of: | View Page |
| The etiologic agent of the superficial skin infection tinea niger palmaris (plantaris) is: | View Page |
| The dimorphic fungus that may produce black, yeast-like colonies after prolonged incubation at 37°C is: | View Page |
| The colonies shown in the upper image were obtained on blood agar from a sputum specimen after 10 days incubation at 30°C. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony. The diagnosis is: | View Page |
| The growth of the colonies shown in the upper image was obtained on blood agar from a sputum specimen after 8 days of incubation at 30°C. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony. The diagnosis is: | View Page |
| The colonies shown in the upper image, obtained from a biopsy of an ulcerating skin lesion of the arm, are growing on agar slants of Sabouraud's dextrose agar. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony growing in the left slant. The diagnosis is: | View Page |
| One of the characteristics common to the dimorphic molds is the ability to convert the mold forms to the yeast forms by incubating subcultures in enriched media at 35°-37°C. The upper image illustrates a subculture of a mold colony suspected of being a dimorphic fungus inoculated to the surface of blood agar and incubated for 3 days at 37°C. Note that the colonies have a prickly appearance, suggesting an intermediate stage of conversion. The lower image is a lactophenol blue mount of a portion of one of the prickly colonies. This fungus can be identified as: | View Page |
| The colonies growing on the surface of this brain-heart infusion with blood agar plate were "converted" from a mold colony suspected of being Histoplasma capsulatum by incubating a subculture at 37°C for 5 days. The yeast forms that must be identified in mounts made from one of these colonies to confirm the identification are: | View Page |
| Match the names of each of the yeast species with its most likely colony morphology as seen in the images on the right. | View Page |
| Match the names of each of the species of yeast listed with its associated phenotypic property that is helpful in establishing a species identification. | View Page |
| Arrange in sequence the steps that should be taken to make a definitive identification of Cryptococcus neoformans. | View Page |
| The growth of the yeast-like colonies shown in the upper image was obtained on blood agar from a skin culture only in the area overlaid by virgin olive oil. The lower image is a photomicrograph of a lactophenol blue mount made from a portion of the colony. The disease associated with this fungus is: | View Page |
| The forms seen in this photomicrograph, produced from a light inoculum of an unknown yeast colony incubated in rabbit plasma at 35°C for 2 hours, leads to the presumptive identification of: | View Page |
| The colony shown in the upper image was recovered from peritoneal fluid of a patient receiving continuous peritoneal dialysis. The lower image is a photomicrograph prepared from a small portion of the colony illustrating the microscopic morphology. Each of the following species of yeast can be eliminated except: | View Page |
| This photomicrograph is an acid-fast stained smear prepared from a yeast colony growing on ascospore agar. A helmet-shaped, red-staining, acid fast yeast cell is seen in the center of view at the tip of the arrow, against the background, blue-staining blastoconidia. The presumptive identification of Hansenula anomala was made. Predisposing conditions that may indicate that this isolate is more than a contaminant include: | View Page |
| Principle The culture smear is used to determine the staining characteristic and shape of the unknown organism since this data helps the microbiologist to decide on additional culture and identification methods. By correlating the Gram stain reaction, colony morphology and growth requirements, the microbiologist may be able to tentatively identify the organism, which the physician may use to modify treatment, until definitive culture and antibiotic susceptibility results become available. | View Page |