AEROBIC GRAM-POSITIVE BACILLI Flashcards
Microscopic appearance of Bacillus
Large, boxcar-shaped, gram (+) rods with clear, unstained, central spore of “empty space”
Spore-forming, facultative anaerobic, motile, (+) Catalase and VP
Bacillus
Common isolates of Bacillus
B. anthracis, B. cereus, B. subtilis, B. thuringiensis. B. pumilus, and B. licheniformis
Clinically significant Bacillus
B. anthracis, B. cereus, B. thuringiensis, and B. mycoides
Common human pathogens of Bacilli
B. anthracis and B. cereus
The causative agent of anthrax
Bacillus anthracis
All bacillus are motile (peritrichous) except:
B. anthracis and B. mycoides
The most pathogenic species in Bacillus and not part of human microbiota
Bacillus anthrax
Appearance of B. anthracis if penicillin (10 U/mL) is added to the culture medium
String of pearl
Virulence factor of B. anthracis
D-glutamic capsule and protein exotoxins (edema factor, protective antigen, lethal factor)
Growth factor of B. anthracis
Thiamine
Microscopic appearance of B. anthracis
Bamboo fishing rod appearance with an unstained central spore
Appearance of colonies in BAP of B. anthracis
Medusa head appearance with swirling projections and non hemoltic
The appearance of B. anthracis if inoculating loop is used to pull up the colonies
Beaten egg white appearance
It is a disease that primarily affects animals, such as goats and sheep, by feeding one plants that are contaminated with the spores and not through animal-to-person transmission
Anthrax
Complication of anthrax
Meningitis
The most common type of anthrax and the least fatal
Cutaneous anthrax
A necrotic and painless central area that does produce pus and seen in cutaneous anthrax
Black eschar
Preferred sample for Cutaneous anthrax
Vesical fluid or swab specimen from the edge of the eschar
It is the most severe form of anthrax
Pulmonary anthrax
Other name for pulmonary anthrax
Woolsorter’s disease
Signs and symptoms of pulmonary anthrax
Mild fever, fatigue, malaise, and dyspnea
Preferred sample of pulmonary anthrax
Sputum
Spores are inoculated into a lesion on the intestinal mucosa following their ingestion
Gastrointestinal anthrax
Signs and symptoms of gastrointestinal anthrax
Abdominal pain, nausea, anorexia, vomiting, and bloody diarrhea
Preferred sample for gastrointestinal anthrax
Stool
This type of anthrax has been identified among users of prohibited drugs
Injection anthrax
This type of anthrax is associated with severe soft tissue infection
Injection anthrax
Preferred sample of injection anthrax
Swab specimens from the affected areas and blood culture
Processing of samples for B. anthracis should only be done in biological safety cabinet with provisions for
Biological safety level 3
Specimen collection requirement for B. anthracis
collect 2 separate swabs, one each for the culture and molecular assay (PCR) and should be pre-moistened with sterile saline
For swab sample intended for both culture and RT-PCR, it should be transported at
2-8 degree Celsius while -70 degree Celsius is the best storage condition if the specimen will be for molecular assay only
It can provide rapid presumptive diagnosis for B. anthracis
Fluorescent microscopy
Gold standard for the laboratory diagnosis B. anthracis
cultivation/culturing
Spore stains for B. anthracis
Malachite green and McFadyean
Enrichment and selective technique for B. antracis
Application of heat or alcohol shock technique before plating
Capsule stain for B. anthracis
India ink
Recommended for identification of B. anthracis in fecal specimen
PEA
Used in isolating Bacillus from contaminated specimens
PEA and PLET
It is used to determine if the produce lecithinase, in which the medium will have an opaque zone
EYA
The appearance of B. anthracis in gelatin medium
Inverted pine tree
It serves as another point of confirmation for the presence of B. anthracis
Direct fluorescent antibody (DFA)
It detects thermostable anthrax antigens and rabbit antiserum to observe precipitin formation
(+) Formation of precipitin band after less than 15 minutes
Ascoli test (Precipitin test)
It is used for initial intravenous therapy until results for the AST are released
Ciproflaixn or doxycycline
This method has been very useful for the accurate differentiation of genus Bacillus from the emerging genera such as Geobacillus, Paenibacillus, and Brevibacillus
MALDI-TOF Spectrometry
It causes food poisoning due to ingestion of contaminated cooked rice dishes or other food products
Bacillus cereus (Fried rice bacilli)
It is the most commonly encountered bacillus spp. in opportunistic infections that causes eye and ear infection
Bacillus cereus
It has frosted glass appearance in BAP
B. cereus
Best specimen for isolation of B. cereus
Suspected contaminated food (>10^5 cells/gram)
It is associated with the ingestion of contaminated poultry, meat, and vegetables
Diarrheal type
Incubation period of Diarrheal type food poisoning of B. cereus
8 to 16 hours
Symptoms of Diarrheal type
Abdominal pain and watery diarrhea without fever
(+) Production of heat-labile enterotoxin
Diarrheal type
It is associated with the ingestion of improperly stored cooked/fried rice
Emetic type
Emetic type is caused by
B. cereus type 1
Incubation period of emetic type bacteria
1 to 6 hours
Symptoms of emetic type
Abdominal cramps, nausea, and profuse vomiting but no fever
(+) Production of heat stable enterotoxin
Emetic type
It is the most commonly encountered laboratory contaminant
Bacillus subtilis (Hay bacillus)
It is the source of bacitracin antibiotic
B. subtilis
It is used as a biological indicator in sterilization method
B. pumilus
BAP- Colonies are large and moist with a blister like appearance, and beta hemolysis
Bacillus pumilus
Majority of these species are found as indigenous microbiota on the skin and mucous membranes of humans and animals and found in fresh water, salt water, soil, and air
Corynebacterium
Corynebacterium is closely related to
Mycobacterium and Nocardia
The cell walls of Corynebacterium contain
Mesodiaminopimelic acid
Corynebacterium are glucose and maltose fermenter except
C. urealyticum and C. psuedodiptheriticum
Have a “club-shaped” appearance and palisade arrangement. Cells are highly pleomorphic, arranged in pairs, and create X, V,Y, and L formations that closely resembles Chinese letter
Corynebacterium
non-sporeforming, facultative anaerobe, non encapsulated, non motile, highly pleomorphic, glucose and malatose fermenter
(+) catalase and oxidase
Corynebacterium
This groupof corynebacterium are fastidious corynebacteria that require 48 hours of incubation before any growth can be observed. The addition of lipids in the culture medium enhances the bacterial growth
Lypophilic corynebacterium (C. jeikeium and C. urealyticum
This group of corynebacterium exhibit fermentative or oxidative metabolism
Non-lipophilic corynebacteria (C. amycolatum, C. diptheriae, C. psuedotuberculosis, C. striatum, C. ulcerans, C. xerosi)
It is also known as the diptheria bacillus or Kleb-Loffler bacillus
Corynebacterium diptheriae
Not part of the indigenous microbiota of the respiratory tract, and it only inhabits the human nasopharynx in a carrier state
Corynebacterium diptheriae
Preferred medium for Corynebacterium diptheriae
Enriched medium with serum, cystine, and potassium tellurite
Best specimen for C. diptheriae
Nasopharyngeal and throat swab
Biotype of C. diptheriae with small, shiny, and grayish black colonies; small zone of B-hemolysis
Intermedius
Biotype of C. diptheriae with medium sized colonies, convrx, smooth with black pigmentation and “fried egg” appearance, B-hemolytic
Mitis
Biotype of C. diptheriae with medium sized colonies, convex, smooth with black pigmentation and “fried egg” appearance, B-hemolytic
Mitis
Biotype of C. diptheriae with medium sized colonies, grayish black in color, and opaque; small zone of B-hemolysis
Belfanti
Biotype of C. diptheriae with large, flat, and glossy smooth grayish-black colonies with “daisy-head” appearance, non hemolytic
Gravis
It is a heat-labile polypeptide produced by strains with lysogenic B-phage that carries TOX gene, and causes tissue necrosis and exudate formation
Diptheria toxin
It is an acute, infectious disease that is characterized by the production of a systemic toic and false membrane lining (pseudomembranous formation) of the the throat that may eventually lead to respiratory obstruction
Respiratory diptheria
Sign and symptoms of Respiratory diptheriae
Low-grade fever, thick mucopurulent nasal discharge, and cough
It is characterized by slow, non-healing ulcers and membrane formation. The toxin is absorbed systematically but is less severe
Cutaneous or skin diptheria (Veldt sore or Borcoo rot)
It is part of indigenous flora of the skin and nasopharynx, and isolated from various human biofluids that causes ear infection and bloodstream and prosthetic joint infections specially in immunocompromised patients
Corynebacterium amycolatum
It is a skin microbiota that is found in inguinal, axillary, and rectal sites, an obligate aerobe and a multi-antibiotic resistant bacterium.
Corynebacterium jeikeium
It is the common cause of diptheroid prosthetic valce endocarditis
Corynebacterium jeikeium
It is an indigenous microbiota of the human nasopharynx that causes diptheria-like respiratory infection, UTI, and cutaneous wound infections in immunocompromised patients with AIDS
C. pseudodiptheriticum (Hoffman bacillus)
It is an animal pathogen where humans can contract through direct exposure with infected animals. It produces a demonecrotic toxin that causes death of cells. Rare cause of granulomatous lymphadenitis
C. psuedotuberculosis
It is acquired through the consumption of unpasteurized dairy products, associated with diptheria-like sore throat. It is also isolated from skin-ulcers and exudative pharyngitis
C. ulcerans
Most frequently isolated and most clinically significant Corynebacteria
C. urealyticum
The preferred medium for Corynebacteria and a modification of Tinsdale agar. It is both selective and differential medium
(+) Black or brown colonies surrounded by brown halo
C. diptheriae, C. ulcerans, and C. psuedotuberculosis
The preferred medium for Corynebacteria and a modification of Tinsdale agar. It is both selective and differential medium
(+) Black or brown colonies surrounded by brown halo
C. diptheriae, C. ulcerans, and C. psuedotuberculosis
Skin test for C. diptheria
Schick test
Both a human and animal pathogen with tumbling motility and umbrella like/ inverted christmas tree in SIM media
L. monocytogenes
It is a serious infection that affects neonates, pregnant women, and immunocompromised host acquired through ingestion of meat, chicken, dairy products and vegetables
Listeriosis
A listeriosis that occurs during third trimester that leads to miscarriage or still birth (granulomatosis infantisepticum)
Maternal disease
A Listeriosis that is associated with intrauterine infection due to aspiration of infected amniotic fluid. The infected infant appear healthy at birth, then meningitis develops at third week of life
Neonatal disease (Late-onset neonatal listeriosis)
Enrichment technique for L. monocytogenes
Cold enrichment technique (4 C using broth, then incubated for weeks)
L. monocytogenes is sensitive to antibiotics like
Aminoglycosides and penicillin
It is the only catalase-negative, non-spore-forming, gram-positive, rod-shaped bacterium that produce hydrogen sulfide
Erysipelothrix rhusiopathiae
It has a pattern of pipe cleaner or a test tube brush at 22 degree C in gelatin stab culture
E. rhusiopathiae
Best specimen for Erysipelothrix
Tissue biopsies or aspirates from skin lesions
It is a microbiota of the skin and upper respiratory tract with pleomorphic rods, non-motile, non-spore forming, and catalase negative. They can cause soft tissue infection, pharyngitis, and endocarditis
(+) Lipase, Lecithinase, Reverse CAMP
(-) Catalase
Arcanobacterium
Obligately aerobic, non-spore forming, Gram positive rods that are motile
(+) Catalase
(-) Gelatinase and oxidase
Kurthia
It is a normal flora of oropharyngeal which can be isolated in saliva and dental plaque with “coccal to rod appearance”
(+) Bile esculin hydrolysis and nitrate reduction
(-) Urease
Rothia
It is isolated from contaminated blood culture bottles and intensive care unit
Paenibacillus
It is a partially acid-fast bacilli, obligate aerobic, and non-motile. Their cell wall contains peptidoglycan, meso-diaminopimelic acid (DAP), and the sugars, arabinose and galactose
(+)Catalase, urease, and nitrate reduction
Nocardia
The colonies appearance of Nocardia
Exhibit wrinkled, “chalk-like” appearance, sometimes waxy with “plowed field” odor
It is a confluent bronchopneumonia where the sputum is thick and purulent although the encapsulation of the abscess is absent and without granuloma formation
Pulmonary nocardiosis
Causative agent of Pulmonary Nocardiosis
N. cyriacigeorgica and N. farcinica
It is a chronic, localized, painless subcutaneous infection that is characterized by the presence of draing pus and sulfur granules
Cutaneous nocardiosis (Actinomycotic/bacterial mycetoma)
It is utilized to observe the branching filaments and partially acid-fast characteristics of Nocardia
Modified Kinyoun method
It is used for histopathological examination of tissue specimen
Gomori’s methenamine silver (GMS)
Most common causative agent of cutaneous nocardiosis
N. brasiliensis
Nocardia spp are susceptible to _____ and resistant to beta-lactam drugs like ______
sulfonamides, penicilin
It is asaccharolytic, non-motile, and partially acid-fast, with its cell wall composed of long chain mycolic acid. It exhibit a zigzag and scanty branching patterns with pale/ salmon pink in BAP
Rhodococcus equi
It is partially acid-fast and non motile. Use 16S rRNA sequencing which serves as the differential marker. It has been isolated from surgical wound, coronary artery infection, and pulmonary disease
Gordonia
Gram positive, non motile, and shaped like long rods that fragments into three parts. Slightly acid fast when the Kinyoun method is used
Tsukamurella
Gram positive rods with branching filament but variable hyphae. With “spore-like bodies” and extensive branching but does not fragment and “musty basement order”
Streptomyces
Streptomyces that is a human pathogen
S. somaliensis (agent of actinomycotic mycetoma)
Distinguishing feature of Steptomyces
Extensive branching but does with aerial hyphae (Tap water agar test)
It causes bacterial mycetoma (“madura foot” or “madura belt”) same with Nocardia
Actinomadura
In routine agar in exhibit a “molar tooth” appearance
Actinomadura
Gram positive actinomycete and a facultative intracellular pathogen that reside the macrophages. The etiologic agent of Whipple’s disease that affect the gastrointestinal tract, joint, and muscles
Tropheryma whipplei
Preferred specimen for Tropheryma whippleo
Doudenal biopsy
Gold standard test for identification of Tropheryma whipplei
Periodic acid-Schiff staining
characterized by trismus and risos sardonicus. It occurs when the organism enters an open wound and spread a potent toxin that mediates generalized muscle spasms
Tetanus
Symptoms and incubation period of tetanus
Muscular rigidity and difficulty in swallowing, 3 to 21 days (depending on the distance from the injury to CNS)
It is contracted through the use of contaminated instruments on newborns
Tetanus neonaturum
Other name of Clostridium botulinum
Canned food baciilus
Von Ermengen’s bacillus
Pigsbel bacillus
It is a potential bioterrorism agent and characterized by the presence of OVAL, SUBTERMINAL SPORES
Clostridium botulinum
It is considered as one of the most potent natural toxins known to man. It also requires a small amount of this neurotoxin to cause fatality, produce paralysis, and death
Botulosm toxin (BoNT-Butolism Neurotoxin)
It is characterized by double or blurred vision, impaired speech, difficulty in swallowing, weakness, and paralysis
Botulism
It results from the ingestion of preformed botulism toxin in preserved or meat-based food. It is commonly caused by botulism toxin A
Foodborne botulism
It is an infection that is caused by ingesting the organism from honey products added to milk
Infant botulism
Tends to proliferate as skin microbiota of hospitalized individual; associated with indwelling devices such as catheter and prosthetic valves
C. jeikeium (JK bacillus)
Normal microbiota in humans and cattles, caused bovine mastitis
C. ulcerans
Causes erythrasma
C. minutissimum
It is the most common cause of antibiotic-associated diarrhea and pseudomembranous colitis (bloody diarrhea with necrosis of colonic mucosa)
Clostridium difficle
Preferred culture medium for C. difficle
Cycloserine-cefoxitin-fructose agar (CCFA)
Virulence factor of Clostridium difficle
Toxin A (enterotoxin) and Toxin B (cytotoxin)
Colonies are flat with a “horse stable” odor, non hemolytic, and produce fluorescent chartreuse under long UV light
Clostridium difficle
Young colonies -“spider-like” or wooly” appearance
Old colonies -“molar tooth” appearance
Actinomyces israelii
Pale staining, pleomorphic, gram (-) rods with safety pin appearance
Bacteroides fragilis
Colonies corrode (pit) the agar
Bacteroides urealyticus
Gram-positive diptheroids; that are coccoid or pointed in shape with bifurcated (forked) ends which resemble the shape of “dog bone”
Bifidobacterium
May exhibit filamentous growth; with a translucent colonies with black center resembling “fish eye” colonies
(+) H2S production;bile resistant
Bilophilia wadsworthia
Pleomorphic, gram-positive rods that are seagull wing-shaped
Eubacterium
Resemble capnocytophaga. The medium exhibit a green color when expose to air; colonies have “breadcrumbs-like” appearance
Fusobacterium nucleatum
It is the most common cause of anaerobic bacteremia (frequently isolated from blood cultures)
Bacteroides fragilis (Bile tolerant anaerobe)
The frequently encountered anaerobic gram-positive cocci
Peptostreptococci
The most pathogenic in the anaerobic in the group of Lactobacillus and often associated with endocarditis, meningitis, and pneumonia
Finegoldia magna
It protects the female genital tract from urogenital infections
Lactobacillus acidophilus
The most commonly isolated anaerobic gram-negative cocci in the lung and brain abscess and infection involving oral cavity
Veillonella
Foul odor is emitted upon opening an anaerobic jar or pouch
Clostridium difficile, Fusobacterium, and Porphyromonas
Presence of sulfur granules
Actinomyces, Cutibacterium, and Eubacterium nodatum
Presence of brick-red flourescence when exposed to ultraviolet light
Prevotella and Porphyromonas
