Miscellaneous GNB-Coccobacilli Exam 3 Flashcards
Vibrio general info.
Oxidase pos. Gram neg bacilli. Ferments glucose. MAC pos. Non-lactose fermenter except for V. vulnificus. Facultative anaerobes. likes h20 environment. NOT apart of normal flora.
Aeromonas general info
Oxidase pos. Gram neg bacilli. Ferments glucose. MAC pos. Non-lactose fermenter except for V. vulnificus. Facultative anaerobes. likes h20 environment. NOT apart of normal flora. Produces deoxyribonuclease.
Chromobacterium general info.
Oxidase pos. Gram neg bacilli. Ferments glucose. MAC pos. Non-lactose fermenter except for V. vulnificus. Facultative anaerobes. likes h20 environment. NOT apart of normal flora.
What is the specimen for vibrio, aeromonas ,and chromobacterium?
Stool or rectal swabs (stool needs to be transported in Cary-Blair medium when vibrio is suspected.
What is the selected media for Vibrio spp?
Thiosulfate citrate bile salts sucrose (TCBS). Bile salts inhibit gram pos organisms and high ph (8.6) inhibits other intestinal flora.
Presumptive ID for Vibrio?
Medium to large, smooth, opaque colonies with greenish hue on SBAP.
Presumptive ID for Aeromonas?
Large, round, raised, and opaque.
Chromobacterium- Presumptive ID?
round, smooth, convex, black to dark purple with almond like smell on SBAP.
Should oxidase testing be done on MAC plate?
No. Fermentation of lactose can create acids that can acidify the medium and if falls below pH of 5.1 can get false negatives.
What organism is the cause of cholera?
Vibrio cholerae
How is cholera mostly transmitted?
Through contaminated seafood ( waters exposed to feces)
What vibrio serotypes have been involved in epidemics/pandemics?
01 and 0139
What virulence factors does Vibrio cholerae have?
Cholera toxin (CT), hemolysins, cytotoxins, and pili.
What does cholera lead to?
dramatic fluid loss (dehydration), hypotension-damage to kidneys, and death can occur. Rice water stools Blood is absent in stool.
What is the treatment for cholera?
Two vaccines OUTSIDE US. Antibiotics decrease severity (Tetracycline and doxycycline). Rehydration is vital.
What kind of specimens are for Vibrio vulnificus?
Wounds, blood, or stool (from ingestion of seafood) oysters Doesn’t spread from person to person.
How do you treat Vibrio vulnificus?
Amputation of infected limbs perhaps. Toxins released include lipases, proteases, and collagenases. *Doxycycline plus ceftazidime recommended.
Signs of Vibrio parahemolyticus?
watery diarrhea, cramping, nausea, vomiting, fever w/in 24 hours. Self-limiting to 3 days. All cases of Vibrio spp. must be reported to state health depts.
What is the treatment for Vibrio parahaemolyticus?
Hydration. Usually no antibiotics (tetracycline in severe cases)
What organism can cause gastroenteritis with diarrhea most commonly in children?
Aeromonas spp. (Aeromonas hydrophilia)
What can Aeromonas spp. cause?
HUS with kidney failure
What organism starts as cellulitis and then progresses to lymphadenitis to systemic infection possible with visceral abscess formation and shock?
Chromobacterium violaceum
What is the treatment for Chromobacterium violaceum?
No set guidelines. Pencillin activity is variable. Cefotaxime is effective
Media for Bartonella?
Fresh chocolate NO BAP and MAC
Media for Streptobacillus moniliformis?
Sheep in increased CO2 and humidity.
Media for Helicobacter?
Chocolate or Brucella agar
Campylobacter media?
CAMPY-BAP, CAMPY CVA, and CCDA (modified charcoal cefoperazone deoxycholate agar
Media for Brucella?
Brucella agar (adds heated horse serum)
Media for Francisella tularensis?
Media with cysteine (buffered charcoal yeast extract agar)
What causes Tularemia (disease with a fever of 104 degrees C)?
Francisella tularensis
B. Quintana and B. henselae most commonly associated with ….
Human disease
Trench fever
B. Quintana (now reemerging as bactermia, endocarditis, lymphadenopathy)
Cat scratch fever, bacteremia, enlarged lymph nodes and pustule at sight of infection from cat infection with fleas harboring the organism?
B. henselae
Specimen for Bartonella spp?
Blood (lysed) and tissues
Incubation for Bartonella spp?
Prolonged (2 weeks) with CO2 and high humidity
Rat bite fever? From what organism?
Lymphadenitis, rash, flu-like symptoms, relapsing fever, chills. Systemic illness (arthritis, meningitis, liver, spleen, etc.) Streptobacillus monoiliformis
Haverhill fever? From what organism?
ingesting contaminated milk rather than a rat bite (more pronounced GI symptoms). Streptobacillus moniliformis.
What is the specimen of choice H. pylori?
Biopsy specimens
H. pylori-urease test?
Positive
What can H. pylori cause?
Chronic gastritis, peptic ulcer disease, gastric carcinoma.
How can H. pylori survive in the stomach?
They secrete urease that produces ammonia and CO2 so it acts like a buffer for the HCL. Also secretes proteases and phospholipases that break down glycoproteins in mucus. destroying 1st line of defense (ulcers)
Which organisms prefer micro aerobic (5-10% O2) environments?
Campylobacter and Acrobacter
These organisms have animal reservoirs (pigs, poultry, sheep, bulls)
Campylobacter and Acrobacter
This genera is the most common bacterial agent of gastroenteritis in the US
Campylobacter (2nd-Salmonella; Norovirus most common cause of acute gastroenteritis)
Presumptive ID-Campylobacter?
Gray to pink to yellow gray colonies. Mucoid.
Treatment for Campylobacter?
Erythromycin *usually self-limiting and don’t require antibiotics.
3 Major pathologies from Campylobacter?
Febrile systemic disease, periodontal disease, and gastroenteritis.
What is associated with neonatal meningitis or compromised adults?
Chryseobacterium
Definitive ID-Chryseobacterium?
MAC pos. Oxidase pos. glucose oxidizer.
What organism is normal flora of dogs and cats?
Bordetella bonchiseptica
Definitive ID-Alcaligenes and Bordetella (nonpertussis)
MAC pos. oxidase pos. non-glucose utilizers.
What organisms are capnophiles?
Actinobacillus, Aggregatibacter, Kingella, Cardiobacterium, and Capnocytophaga
**all ferment glucose, MAC neg, Oxidase pos.
What are the organisms of HACEK?
Aggregatibacter aprophilus, Aggregatibacter actinomycetemcomitans, cardiobacterium hominis, Eikenella corrodens, Kingella spp.
HACEK is found most common where?
Normal flora in oral cavity, upper respiratory, and genitourinary tracts.
Where is Cardiobacterium hominis isolated from?
Blood cultures only
Definitive ID -Eikenella corrodens
MAC neg, Oxidase pos. pits of the agar where colonies are located. bleach like odor.
What is Eikenella corrodens associated with?
Human bite wounds or closed fist wounds (facial punches with abrasions)
Media for K. denitrificans?
Thayer Martin* N. gonnorrhoeae also on media so have to differentiate with ID. K is catalase neg superoxol neg and nitrate pos.
Summary-MAC pos. Oxidase neg.
Enterobacteriacae, Acinetobacter, Chryseomonas, Flavimonas, Stenotrophomonas.
MAC-pos. Oxidase pos.
Pseudomonas, burkholderia, achromobacter, chryseobacterium, alcaligenes, bordetella (nonpertussis), vibrio, aeromonas, plesiomonas shigelloides, chromobacterium violaceum
MAC-neg. Oxidase-pos.
Sphingomonas, Moraxella and elongated Neisseria, Eikenella corrodens, Pasterella, Actinobacillus, Kingella, Cardiobacterium.
MAC-neg. Oxidase-variable.
Haemophilus
