Gram Positive Rods Flashcards
Bacillus spp. Characteristics
most are saprophytes and opportunistic; produce spores, catalase positive, gelatin positive, and mostly motile; large rods in gram stain with boxcar shape
What are the different types of anthrax infections?
Cutaneous anthrax, pulmonary anthrax, GI anthrax, and injectional anthrax
Cutaneous Anthrax
occurs at the site of penetration and it progresses from an erythematous papule to ulceration (escher) and then toxemia and death; lymph nodes may swell
Pulmonary Anthrax
follows inhalation of spores and progresses from malaise with mild fever to chest edema, cyanosis, and death (shock and death occur 24-36 hours after onset)
GI Anthrax
ingestion of spores that affects the oropharyngeal or abdominal area; vomiting of blood and bloody diarrhea are main symptoms; most die of toxemia and sepsis
Injectional Anthrax
injection of contaminated drugs; may result in shock, coma, organ failure, and necrotizing fasciitis
How is B. anthracis treated?
ciprofloxacin or doxycycline plus one or two other antibiotics; resistant to B-lactams
What are the two types of food poisoning caused by Bacillus spp.?
Diarrheal type with abdominal pain and emetic type with vomiting
Bacillus anthracis Identification
nonhemolytic, nonmotile, growth anaerobically, lecithinase positive, ADH negative, nitrate positive, capsule positive, and susceptible to Gamma phage and penicillin G
Bacillus Cereus Identification
causes food poisoning and other opportunistic infections; grows anaerobically, motile, lecithinase positive, variable for ADH and nitrate, B hemolytic, capsule negative, and resistant to Gamma phage and penicillin G
Bacillus cereus biovar anthracis
Cote d’lvoire strain (C1): nonhemolytic, variable motility, capsule positive, susceptible to penicillin G, and resistant to Gamma phage
Cameroon strain (CA): nonhemolytic, variable motility, capsule positive, resistant to gamma phage and penicillin g
Other Bacillus spp Identification
B. licehniformis: grows anaerobically, motile, lecithinase negative, nitrate positive
B megaterium: no anaerobic growth, motile, lecithinase negative, ADH negative, nitrate negative
B. mycoides: grows anaerobically, nonmotile, lecithinase positive,
B. pumilis: no anaerobic growth, motile, lecithinase negative, ADH negative, and nitrate negative
B. subtilis: no anaerobic growth, motile, lecithinase negative, ADH negative, nitrate positive
B. thuringiensis: grows anaerobically, motile, lecithinase positive, ADH positive, and nitrate positive
Corynebacterium Characteristics
normal flora; non-spore forming, small, pleomorphic rods that can be club-shaped or curved; do not require CO2 to grow, aerobic/facultative anaerobic; nonmotile and catalase positive
Corynebacterium diphtheriae diseases
Infects the upper resp. tract in humans to cause diphtheria; there are toxigenic and nontoxigenic forms based on the presence of a bacteriophage with the toxin gene.
Diphtheria symptoms
a pseudomembrane of necrotic epi. cells, WBC, bacteria, and fibrin can obstruct the airway; the toxin can be absorbed and cause damage to the heart and nervous system
Tellurite media
Cystine-tellurite medium and Tinsdale agar have tellurite, allowing for isolation of corynebacterium and differentiate C. diphtheriae from other corynebacterium species because it has a brown halo around its colonies
Elek Test
an immunodiffusion procedure that tests for the diphtheria toxin; a precipitate forms on the antitoxin line if the toxin is present
Which two other species of corynebacterium cause serious disease?
C. jeikeium and C. urealyticum
Which two species of corynebacterium can also have the diphtheria toxin gene?
C. ulcerans and C. pseudotuberculosis
C. diphtheriae Identification
Nitrate positive, urease negative, fermenter, glucose positive, maltose positive,
C. jeikeium Identification
Nitrate negative, urease negative, oxidizer, glucose positive
C. pseudotuberculosis Identification
urease positive, fermenter, glucose and maltose positive
C. ulcerans Identification
nitrate negative, urease positive, fermenter, glucose and maltose positive
C. urealyticum Identification
nitrate negative, urease positive, oxidizer, glucose and maltose negative
Archanobacterium Characteristics
cause pharyngitis, wound infections, and bacteremia; B hemolytic, catalase negative, reverse CAMP positive, nonmotile, facultatively anaerobic, non-spore forming, nitrate negative, urease negative
Which coryneform bacteria is positive for xylose?
Arcanobacterium pyogenes only
Rothia dentocariosa characteristics
normal flora in oropharyngeal cavity, associated with dental carries and periodontal diseases; can be mistaken for actinomyces viscosus, but it does not ferment lactose; nitrate positive, urease negative, glucose, sucrose, and maltose positive
Gardnerella vaginalis characteristics
part of anorectal and vaginal flora; associated with bacterial vaginosis, only B hemolytic on horse blood (not sheep), catalase negative, nitrate negative, urease negative, glucose and maltose positive
Listeria monocytogenes characteristics
aerobic, non-spore forming GPR; causes infections in pregnant women, newborns, elderly, and people with compromised cell-mediated immunity (AIDs, transplants, etc.); usually acquired from meat or raw milk
L. monocytogenes Identification
B hemolytic, catalase positive, tumbling motility at 25C (not 35C) and umbrella pattern on motility media, bile esculin positive, hippurate positive, CAMP positive, H2S negative, grows at 4C
Erysipelothrix rhusiopathiae characterisitics
infections are caused by abrasion or puncture wound of skin with animal exposure, leading to erysipeloid on hands (seen in butchers, farmers, and seafood handlers); thin, non-spore forming GPR
Erysipelothrix rhusiopathiae Identification
nonmotile, catalase negative, alpha or gamma hemolytic, H2S positive, test tube brush growth in gelatin swab; resistant to vanc., T/S, and aminoglycosides
Lactobacillus spp. Characteristics
non-spore forming GPR that form medium to long chains of rods; rarely cause disease and are normal flora in humans, but can cause endocarditis, bacteremia, pneumonia, and meningitis
Lactobacillus spp. Identification
some will only grow anaerobically while others are facultatively anaerobic; nonmotile, catalase negative, alpha or gamma hemolytic
Aerobic actinomycetes characteristics
Filamentous rods that tend to brand; found in soil and water; growth is enhanced by CO2 and take up to 4 weeks to grow
Nocardia spp. characteristics
Partially acid fast with a beaded gram stain; Causes nocardiosis (a chronic disease that can affect any organ) and actinomycotic mycetoma leading to sulfur granules
Nocardia spp Identification
catalase positive, strictly aerobic, oxidatively utilizes sugars including paraffin as an energy source; lysozyme test positive (resistant)
N. asteroides Identification
Casein, tyrosine, xanthine, and starch negative, urea positive (positive = clearing of milky media)
N. brasiliensis Identification
Casein, tyrosine, and urea positive, xanthine and starch negative
N. otitidiscaviarum Identification
Casein, tyrosine, and starch negative, xanthine and urea positive
How is Tropheryma whipple diagnosed?
It will stain positively with a partially acid fast stain and histological testing shows foamy macrophages in lamina propria of the small intestine
Whipple disease symtoms
diarrhea, weight loss, lymphadenopathy, fever, skin pigmentation, and arthralgia
Rhodococcus spp Characteristics and Diseases
GPCB, partially acid fast, obligate aerobe, catalase positive, salmon color and slow growing; causes granulomatous pneumonia and lung lesions in immunocompromised people
Gordonia and Tsukamurella Diseases
opportunistic pathogens, associated with catheter-related sepsis, central nervous system infections, pulmonary infections, and cutaneous infections
Which two aerobic actinomycetes are not partially acid fast?
Streptomyces and Actinomadura
Actinomadura spp. diseases
can cause actinomycotic mycetomas
Actinomadura madura Identification
Casein, tyrosine, and starch positive, and urea and xanthine negative
Actinomadura pelletieri Identificaton
Casein and tyrosine positive, and xanthine, starch and urea negative
Streptomyces spp. Diseases
can cause actinomycotic mycetomas
Streptomyces somaliensis Identification
Casein and tyrosine positive, and xanthine and urea negative
Streptomyces anulatus Identification
Casein, tyrosine, xanthine, and starch positive
