Bacteriology part 2 Flashcards
-Found in domesticated animals
-Often transmitted through contaminated pork, water or milk
-Causes bloody diarrhea, manifests with fever, abdominal pain, nausea, vomiting
-Can cause inflammation around appendix or in mesenteric lymph node
-May mimic Crohn’s disease or appendicitis
Yersinia enterocolitica
-Cause of bubonic plague (“black death”)
-Humans get disease from rat flea bites Xenopsylla cheopsis
Yersinia pestis
-Chief reservoirs are reptiles and freshwater fish
-Infections often involve aquatic environments
-H2S (+)
-Indole (+), differential from Salmonella
Edwardsiella tarda
-Only oxidase (+) Enterobacteriaceae
-Pleomorphic Gram negative rods in singles, pairs, short chains, or long filaments
-Grows on SBA, CHOC. Most grow on MAC, appear as NLF. Does not grow on TCBS
-Biochemical and antigenic similarities to Shigella
-Oxidase (+)
-Motile
Plesiomonas shigelloides
-Most common non-fermenter
-GN, motile rods with single polar flagella
-Beta hemolytic, obligate aerobe , producing sweet or grape-like or corn taco-like odor
-Oxidizes glucose
-Citrate (+)
-Oxidase (+)
-Catalase (+)
Pseudomonas aeruginosa
Nonfluorescing bluish pigment
Pyocyanin
Fluorescent yellow pigment
Fluorescein
Fluorescent green pigment
Pyoverdin
Dark red pigment
Pyorubin
Black pigment
Pyomelanin
Transmission is via water aerosols, raw vegetables, flowers
P. aeruginosa
-Often found in nosocomial infections
-Infections in burn sites, wounds, urinary tract particularly in immunocompromised patients
-gives rise to blue-green pus
P. aeruginosa
Causes meningitis when introduced by lumbar puncture during a neurosurgical procedure
P. aeruginosa
Causes chronic pneumonia in cystic fibrosis patients (an exopolysaccharide, alginate, is responsible for the mucoid colonies seen in cultures from these patients)
P. aeruginosa
-Causes mild otitis externa in swimmers (“swimmer’s ear”)
P. aeruginosa
Causes eye infection after surgery or surgical procedures
P. aeruginosa
Causes fatal sepsis in infants or debilitated persons.
P. aeruginosa
-Lesions seen in P. aeruginosa that causes fatal sepsis in infants or debilitated persons;
-hemorrhagic necrosis of the skin
-Often do not contain pus
Ecthyma gangrenosum
Causes a form of folliculitis associated with poorly chlorinated hot tubs and swimming pools
P. aeruginosa
Causes osteomyelitis in IV drug users
P. aeruginosa
Can cause fever or shock in P. aeruginosa patients
Endotoxin (LPS)
Inactivates elongation factor (EF-2), necessary for protein synthesis
Exotoxin A
-Gram negative rod similar to Pseudomonas
-patients to cystic fibrosis and chronic granulomatous disease
-catalase (+)
-Oxidase (+)
-Lysine decarboxylase (+)
Burkholderia cepacia complex
-Small, non-motile, non pigmented gram negative rods
-Causes disease in horses, mules, and donkeys (glander’s disease)
-Inhalation of organism may lead to pneumonia
Burkholderia mallei
-Small, motile, gram-negative bacillus
-Acquired by inhalation, ingestion or contamination of abraded skin
-Most commonly causes pulmonary infection, which may present as tuberculosis
-Agent of meliodosis (Whitmore’s disease aka Vietnamese time bomb”) acquired by contamination of skin abrasions and possibly by ingestion or inhalation
Burkholderia pseudomallei
-Bipolar “safety pin” staining on Methylene blue/ Wright’s stain
-Aerobic, grows on standard bacteriologic media at 42 deg C
-Oxidase (+)
-Oxidizes glucose, lactose, and a variety of other carbohydrates
B. pseudomallei
Formerly known as Pseudomonas maltophilia, Xanthomonas maltophilia
-Free living gram negative rod that is widely distributed in the environment
-Lavender-green or gray colonies on blood agar
-Oxidase (-)
-DNAse (+)
-LDC and oxidation of glucose and maltose (hence the name)
Stenotrophomonas maltophilia
-Aerobic, gram negative bacteria widely distributed in soil and water
-usually coccobacillary or coccal in appearance
-commensals but occassionally cause nosocomial infection
-grows well on most types of media
-nonhemolytic
-catalase (+)
-may be mistaken for Neisseria
-oxidase (+)
-often multidrug resistant
Acinetobacter baumanii
-easily confused with N. gonorrhoeae
-does not ferment glucose and grows on nutrient agar
-oxidase (+)
-nonmotile
Moraxella osloensis
-isolated in soil and water, including moist hospital environments
-transmission: contaminated medical devices and solutions
-oxidase (+)
-non lactose fermenting
-motile rods with peritrichous flagella
-feather-edged colonies surrounded by a zone of greenish discoloration on BAP
-Odor: Fruity odor resembling apples or strawberries
Alcaligenes fecalis
Pfeiffer’s bacillus
H. influenzae
most common cause of meningitis in infants under 2 years of age in the US
H. influenzae type B
Type of H. influenzae that causes epiglottis (“cherry red” epiglottis), pneumonia, cellulitis, otitis media
Type B
-Also knowns as Koch-Weeks bacillus
-cases pink eye conjuctivitis
H. aegyptius
-Cause of ulcerative chancroid, and STD seen as a painful genital ulcer
-gram stain: “schools of fish”
H. ducreyi
Dew drop colonies
H. influenzae
Haemophilus colonies grow more luxuriously next to Staphylococcus streak -
“Satellite phenomenon”
Test for the strains that do not require X factor.
ALA (delta-aminolevulini acid) test
-small coccobacillus, non-motile and hemolytic
Bordetella
“Whooping cough; 100 day cough”
-transmitted by aerosolized droplets
-produces pertussis toxin, which impairs recruitment of neutrophils
-requires special media
-urease (-)
B. pertusis
3 stages of pertusis
- Catarrhal - most contagious
- Paroxysmal - whooping cough
- Convalescent - recovery
Bordetella
-motile (peritrichous)
-urease (+)
-oxidase (-)
B. bronchoseptica
Bordetella
-nonmotile
-urease (+)
-oxidase (+)
B. parapertussis
-Fastidious
-gram neg rod but does not gram stain well
-silver stains used
Legionella
-requires iron and L-cysteine
-best medium is BUFFERED CHARCOAL YEAST EXTRACT AGAR (BCYE)
Legionella
-First identified at American Legion convention
-infection from inhalation of aerosolized bacteria
Legionella pneumophila
2 infections caused by Legionella pneumophila
- Legionnaire’s disease
- Pontiac fever
multi-system disease, (not only pulmonary, but gastrointestinal, central nervous and renal systems)
Legionnaire’s disease
-formerly Haemophilus vaginalis
-tiny fastidious rod, gram reaction variable
-common in genital tract women with vaginitis, occasionally causes neonatal sepsis, postpartum bacteremia
Gardnerella vaginalis
Best culture medium for G. vaginalis
Human Blood Tween agar (HBT)
“Sniff” test on vaginal discharge (10% KOH)
G. vaginalis
vaginal epithelial cells covered with bacteria - usually found in wet mount of discharge
Clue cells
-fermenter, oxidase (+); not a member of Enterobacteriaceae
-causes voluminous “rice-water” diarrhea
Vibrio cholerae
V. cholearae is best isolated in __
Alkaline (pH 8.4) peptone broth
Best agar medium on V. cholerae
Thiosulfate Citrate Bile Salts (TCBS) agar
yellow colonies: sucrose fermenter
Test wherein V. cholerae is viscid and forms a string, when lifted from the slide with a loop, that persists for 45-60 seconds
String test
Any organism that is indole (+) and NO3 (+) is also ___ positive
Cholera red (+)
Both cause food poisoning (diarrhea) found in raw oysters
-obligate halophile (requires 3-7% NaCl)
-Grows on XLD agar, but alkaline peptone water and TCBS agar best
-String and cholera rest tests (-)
Vibrio vulnificus and V. parahaemolyticus
-microaerophilic, slender, curved, gram neg rod
-motile with single polar flagellum
Campylobacter
-causes enteritis
-leading cause of acute diarrhea worldwide
-common trigger of GUILLAIN-BARRE SYNDROME , a demyelinating disease characterized by ascending weakness
Campylobacter jejuni and Campylobacter coli
-nonfermentative
-oxidase (+)
-Catalase (+)
-nitrate (+)
-H2S (-)
-grows in 1% glycine
-Hippurate (+)
C. jejuni
-curved, flagellated, motile gram negative rod
-“Triple positive”: catalase (+), oxidase (+), urease (+)
H. pylori
___ hydrolyzes urea to compounds that damage epithelium
-produces ammonium (alkaline)
-protects bacteria from stomach acid
Urease
3 diagnosis of H. pylori
Biopsy
Urea breath test
Stool antigen
slow growing, gram negative bacilli associated with endocarditis: colonizes oropharynx,
-growth enhanced by increased CO2
AACEK Group
-Formerly Haemophilus asphrophilus and Haemophilus paraphrophilus
-uncommon cause of endocarditis
-associated with slowly progressive (subacute) bacterial endocarditis
Aggregatibacter aphrophilus
-small gram negative bacillus
-nonmotile
-resembles Pasteurella.
-causes granulomatous disease in animals
-Colonies: STAR-SHAPE CONFIGURATION
Actinobacillus (Aggregatibacter) actinomycetemcomitans
-Normally found in the upper RT
-isolated as a rare cause of endocarditis (esp with an exisitng heart defect or anatomic heart defects)
Cardiobacterium hominis
-“corroding bacterium”
-small, fastidious, capnophilic, gram-negative rods
-normal flora of the gingival crevices and bowels in 40 - 70% of humans
-infects human bites which may be self-infliceted
-oxidase (+)
-may pit or corrode the agar surface (BAP)
-capnophilic, requires 2-3 days for growth
-odor: “SHARP ODOR OF BLEACH”
Eikenella corrodens
-oxidase positive and ferments glucose
-short coccobacillus with rounded ends
-require blood for growth and may pit the agar
Kingella kingae
-Gram positive sporulating anaerobic rods
-motile with peritrichous flagella
-live as saprophytes
-may produce lecithinase and lipase
-can ferment a variety of sugars (saccharolytic) and digest proteins (proteolytic)
Clostridium
-terminal spores (“lollipop”)
-gelatin hydrolysis (+)
-glucose fermentation (+)
C. tetani
-neurotoxin produced by C. tetani which causes tetanus
-spastic paralysis
-classic symptoms: Lockjaw (trismus) , Risus sardonicus, Opisthothonus
Tetanospasmin
-Ubiquitous organisms found in vegetables, fruits, seafood, soil
-cause the disease botulism (“Floppy baby syndrome” in infants)
C. botulinum
-Toxin produced by the ingestion of food with C. botulinum commonly from canned foods
-works at the neuromuscular junction and prevents ACh release.
-results in no muscle contraction, thus flaccid paralysis
Botulinum toxin
-Type of botulism associated with toxin ingestion from undercooked food usually in adults
Food botulism
Types of botulism wherein there are ingestion of spores –> growth in infant intestine
-associated with contaminated honey
Infant botulism
Types of botulism wherein there is bacterial growth after infection with C. botulinum
Wound
-causes gas gangrene (clostridial myonecrosis)
C. perfringens
Type of toxin that destroys muscle tissue and causes hemolysis
-enterotoxin produced by C. perfringens which causes common food poisoning
-DOUBLE ZONE OF HEMOLYSIS around colonies on blood agar is a characteristic
Alpha toxin
inhibition of anti-perfringens antitoxin of the precipitate around growth on egg yolk agar
Nagler’s test
-cause pseudomembranous colitis in patients
-produces 2 toxins (A and B)
C. difficile
-normal GI flora
-pale gram negative rods with irregular staining, not dinstinctive
-grow in 20% bile and hydrolyzes esculin
-penicillin (R)
-no butyric acid produced
Bacteroided fragilis
-glucose not fermented
-black pigment on laked blood agar
-pale, irregular stain, coccobacillary
-fluoresces BRICK RED under UV light at 366 nm
Bacteroides melaninogenicus (B. assacharolyticus)
Pitting of agar
Bacteroides ureolyticus
-thin gram negative rod with tapered ends, often in pairs end-to-end
-inhibited by 20% bile
-greening around colonies on blood agar after exposure to room air temperature for 15 minutes
-produces a large amount of butyric acid from glucose fermentation
Fusobacterium nucleatum
-Gram positive nonsporulating anaerobic rods
-catalase and indole (+)
-produces propionic acid
Cutibacterium acnes (Propionibacterium acnes)
-Gram positive nonsporulating anaerobic rods
-normal oral flora
-also found in female genital tract
-clusters into thin branching long filaments (resembling fungi)
-neither acid-fast nor stained with fungus stains
-catalase, indole, and gelatin (-)
-litmus milk and glucose (+)
-Ferments glucose without production of propionic acid
-SUCCINIC ACID is a major product
Actinomyces
-grows in CO2 on subculture
-colonies grow in BHI under 95% N and 5% CO2 in 2-7 days, 5 mm below surface
-Heaped, rough, lobate colony resembling “MOLAR TOOTH”
Actinomyces
Clinical picture: “Lumpy jaw”
-chronic suppurative and granulomatous disease
-wooden or lumpy lesions
-multiple draining sinuses
Human actinomycosis
-tiny cocci, colonies convex and transluscent
-red fluorescence under UV light of 365 nm
Veilonella
-occurs singly or in small groups, larger than Peptostreptococcus
-catalase (+)
Peptococcus
Packets
Sarcina
-lives in rodents, shed in urine
-spirochete with hooked shaped ends
-causative agent of leptospirosis and Weil disease (ictohemorrhagic leptospirosis)
Leptospira interrogans
-transmitted by Ixodes deer tick; natural reservoir is the mouse
-causes Lyme disease
Borrelia burgdorferi
Stage 1 Lyme disease
Erythema migrans
Transmitted by louse
Borrelia recurrentis
Causative agent of syphilis
Treponema pallidium
Present with painless chancre
Primary syphilis
Disseminated disease with maculopapular rash, condylomata lata
Secondary syphilis
Gummas, aortitis, neurosyphilis
Tertiary syphilis
-included in class mollicutes (cell wall free bacteria)
Mycoplasma
Causes primary atypical pneumonia and has been associated with joint and other infections
Mycoplasma pneumoniae
Cause post partum fever and has been found with other bacteria in uterine tube infections
Mycoplasma hominis
cause of nongonococcal urethritis in men and is associated with lung disease in premature infants of low birth weight
Ureaplasma urealyticum
closely related to M. pneumoniae and has been associated with urethral and other urogenital infections
Mycoplasma genitalium
-highly pleomorphic because they lack a rigid cell wall and instead are bounded by a triple-layered until membrane that contains a sterol
-use glucose as a source of energy; ureaplasma require urea
Mycoplasma
-require addition of serum or cholesterol to the medium to produce sterol for grown
Mycoplasma
“fried egg” colonies
M. hominis
Stain of isolated colony in agar for mycoplasma
Dienes stain
-obligate intracellular gram negative bacteria that lack mechanisms for the production of metabolic energy and cannot synthesize ATP
-cell wall lacks peptidoglycan
-do not gram stain well
Chlamydia and Chlamydophila
Infectious form of chlamydia; enters cell via endocytosis
Elementary bodies (EB)
Reproductive form of chlamydia
replicated in cells by binary fission
Reticulate bodies
-Trachoma, STDs, infant pneumonia, LGV
- often co-infects with N. gonorrhoeae
C. trachomatis
Parrot fever
C. psittaci
-Staining not done routinely
-gram negative or varibale
-Giemsa stain: EBs are purple; host cell cytoplasm and RBs stain blue
-Dilute Lugol’s iodine - appears brown
Chlamydia
Molecular method for the diagnosis of chlamydia
Nucleic acid amplification testing (NAAT)
-small, non motile coccobacilli
-obligate intracellular in man and animals
Rickettsiae
-cause of Trench fever, can be cultivated in cell-free medium
-others grow in yolk sacs of eggs
Rochalimea quintana
Agglutinating antibodies produced react against antigens of certain Proteus strains
Weil-Felix reaction
-Cats harbor fleas
-Cat scratch fever
-bacillary angiomatosis
-endocarditis
Bartonella henselae
-gram negative
-nonmotile
-rod to coccoid shaped
-obligate parasite (intracellular existence)
-causes undulant fever (brucellosis or Malta fever) in man and contagious abortion in goats
Brucella
Culture medium for Brucella
Biphasic Castaneda Bottles (up to 3-4 weeks)
Specimen of choice for Brucella
Bone marrow
Brucella spp that is not detected by serum agglutination test
B. canis
-reservoir:Ticks, deer flies, rabbits
-cause rabbit fever
Franciscella tularensis
Special medium for F. tularensis
Blood-Cysteine-Glucose Agar with Thymine
Tularemia skin test:
Forshay’s test
-lives in mouth of cats and dogs
-nonmotile, oxidase (+)
-fermentative
-facultative anaerobic
-gram negative bacillus
-encapsulated
-small, gram negative rod with bipolar staining
Pasteurella
-causes Tick-borne illness (Lone Star tick)
-white tail deer: principal reservoir
-obligate intracellular bacteria
-“berry-like” inclusions in monocytes (morulae)
Ehrlichiosis
-causes anaplasmosis
-Morula seen in granulocytes (not monocytes)
- Tick vector: Ixodes scapularis
Anaplasma
-fastidious gram negative very pleomorphic, filamentous bacillus
-normally found in the oropharynx of rodents
-causes rat bite fever (Haverhill fever/ streptobacillary RBF)
Streptobacillus moniliformis
-Causes Sodoku, a form of rat bite fever (spillary RBF)
- puff ball/ cotton ball/ bread crumbs appearance in the bottom of the liquid media (strings of pearls in thio)
-fried egg appearance after 5 days of growth
Spirillum minus
