LAB EXAM 1 Flashcards
What are the reagents used for acid-fast staining?
-Kinyoun carbol-fuchsin
-acid alcohol
-Methylene blue counterstain
Why are mycobacteria difficult to stain?
-lipophilic
-cell-wall-bound mycolic acids
What is the reverse CAMP test used to differentiate?
Clostridium perfringens from other Clostridium sp.
Reverse CAMP test:
Colostridium perfringens is streaked at right angles to _______________
Streptococcus agalactiae (group B)
what is the E-test used to determine?
the MIC
What is needed to perform the E-test?
-Muller Hinton Agar
-bacterial suspension
-0.5 McFarland standard
-E-test strip
Two spore-forming anaerobes?
-Clostridium perfringes and botulism and Teni
-bacillus
a genus of Gram-negative, obligate anaerobic bacteria, non-endospore-forming bacilli
Bacteroides
What is the morphology of Clostridium tetani?
drumstick or tennis racket GPR
Gram stain shows “box car” shaped spores
Clostridium perfringens
Clostridium ___________ shows a double zone of hemolysis
perfringens
Morphology of fusobacterium?
gram stain will look slender, spindle shape GNR with tapered ends
To make one end gradually smaller then the other
examples of three types of mircosporum?
-Mircosporum canis
-Mircosporum gyseum
-Mircosporum nanum
Macroconidium vs Microcondiida?
Microconidia: Small, unicellular conidia that are round, elliptical, or pyriform (pear-shaped).
Macroconidia: Large, multi-septate conidia that are club- or spindle-shaped
Fusarium
Bipolaris
Mucor
Histoplasma capsulatam
Blastomyces dermatitidis
Blastomyces dermatitidis
(look for broad base)
What aspergillus species appears green macroscopically?
What appears blue
Aspergillus fumigatus
-Aspergillus flavus (more of a bluish appearance?)
Alternaria
Trichophyton (mentagrophytes) and rubrum
Microsporum canis
Microsporum gyseum
Microsporum nanum
B. dermatitidis
Coccidioides immitis
Coccidioides spherule (spherule containing endospores)
Paracoccidioides brasiliensis (wheel like structure)
Direct detection?
-Calcofluor white
-KOH
-Histology stains
An asexual conidium that forms by a blowing out or budding process
Blastoconidia
What are structures seen in yeast?
What is most common in Candida albicans
-Blastoconidia
-Chlamydospores and pseudohyphae are most common in Candida albicans
Buds elongate, fail to dissociate, and form subsequent buds – they have cell wall constrictions rather than true septa
Pseudohyphae
candida
What does MBC stand for?
Minimum bactericidal concentration- lowest concentration of antibacterial agent required to kill a bacteria.
What does MIC stand for?
Minimum inhibitory concentration- lowest concentration of an antibiotic at which bacterial growth is completly inhibited
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Anaerobic growth chamber indicators:
The pink tablet will turn what color if anaerobic?
remain pink
Anaerobic growth chamber indicators:
Blue strip will change to _______ if anaerobic conditions are maintained.
white
a physical property that gives a bacterium the ability to resist decolorization by acids during staining procedures. This means that once the bacterium is stained, it cannot be decolorized using acids routinely used in the process.
Acid fastness
How is Mucor, Rhizopus, and Absidia differentiated?
-Mucor: without root
-Rhizopus: with root
-Absidia: roots are not directly under sporangiophore (alternating in between)
four dermatophytes…
canis, gypseum, nanum, and Trichophyton mentagrophytes
no root…
mucor
root directly underneath sporangiophore
rhizopus
roots are not directly under sporangiophore (alternating in between)
Absidia
What are two examples of acid fast bacteria?
-Mycobacterium tuberculosis
-Nocardia (weak)
Acid fast positive
Pink or red
Acid fast negative
Blue or green
