Gram Positive Rods and Aerobic Actinomycetes 9/4/15 Flashcards
Describe the key identifying characteristics of Bacillus anthracis.
- Spore-forming
- Gram Positive Rods
- Aerobe
- Non-motile (unlike other Bacilli)
-Non-hemolytic
-Susceptible to penicillin, ciprofloxacin, and doxycycline (when possible terrorist origin)
What bacterial strain can be identified by the following characteristics:
- Non-spore forming
- Gram positive rod
- Beta-hemolytic (like Group B strep)
- Catalase POSITIVE
- Tumbling motility (motile at RT only) = Umbrella motility
Listeria monocytogenes
Describe key identifying characteristics of Erysipelothrix rhusiopathiae.
-Pleomorphic Gram + rods
-Form long filaments (Hair-like)
-Fac anaerobes
-Slow growth (2-3 days)
-Small, grayish, alpha hemolytic colonies
-Catalase NEGATIVE
- non-motile
- weakly fermentative
-Produces H2S on triple sugar iron agar (TSI): turns the media BLACK
What bacterial strain is identified by the following characteristics:
- Pleomorphic Gram positive rods
- Resemble Chinese “letters”: V’s and X’s
- Fac anaerobes
- Small white non-hemolytic colonies
Corynebacterium diphtheriae
-Commonly called “diphtheroids”
Describe key identifying characteristics of Arcanobacterium hemolyticum.
- Non-spore forming
- Gram Positive Rods
- Formation = irregular, club-shaped/curved
- Catalase NEGATIVE
- Beta-hemolytic (similar to Group A strep)
What bacterial strain is identified by the following characteristics:
- Gram + Rods
- Partially acid fast (stains pink)
- Mycolic acid in cell wall
- Strict aerobe
- Nocardia
- Organism in the Actinomycetes group
Describe the epidiology and clinical presentation of infections caused by B. anthracis.
- Anthrax = “coal”
- Category A biothreat agent
- Inoculation, 2. Ingestion and 3. Inhalation (bio weapon):
- Cutaneous:
- Inoculation, 2. Ingestion and 3. Inhalation (bio weapon):
-
Painless papule (20% mortality)
2. GI Anthrax: - Ulcers, nausea, vomiting, malaise, bloody diarrhea (100% mortality)
3. Inhalation: Fever, edema, enlargement of mediastinal lymph nodes (widening of mediastinum see on chest Xray)
What bacterial species is associated with the following epidemiology:
- Plants, meats, dairy contaminated with water/animal feces
- Undercooked and unpasteurized foods (“raw milk”)
- Soft cheeses, veggies, cold cuts contaminated
Listeria monocytogenes
Describe the epidemiology and clinical presentation of infections caused by Erysipelothrix rhusiopathiae.
-Colonization high in swine and turkeys
- Human infection acquired from animals, primarily occupational:
- butchers
- meat processors
- farmers
- fish handlers, etc.
- Cutaneous infections
- Erysipeloid infections:
- localized skin infection, on hands
- appears violaceous with a raised edge
- suppuration uncommon (different from streptococcal erysipelas)
- Septicemic infections:
- Uncommon
- Usually present with endocarditis
- Treatment: PCN is DOC
What bacterial species is associated with the following epidemiology and clinical presentation:
- Almost always non-pathogenic skin flora
- Also colonizes: Upper Respiratory Tract, GI Tract and Urogenital Tract
- Infection transmitted by respiratory droplets/direct contact with cutaneous infection
- Pharyngitis with patchy exudates on tonsils, uvula, soft palate
-Tough gray pseudomembrane = respiratory obstruction and suffocation
Corynebacterium diphtheriae
Describe epidem. and clinical presentation of A. hemolyticum infection.
- Isolated mostly from young adults
- Symptomatic pharyngitis, fever, occ. cutaneous rash
- Some with pseudomembranes on pharynx/tonsils, submandibular lymphadenopathy
- Also isolated from wounds, abscesses and blood of pts with septicemia and endocarditis
What bacterial species is associated with the following epidemiology and clinical presentation:
- Pulmonary diseases
- Cutaneous infections
- CNS infections (brain abscesses)
- Exogenous infections acquired by inhalation (pulm) or traumatic (cutaneous) introduction
- Immunocompetent pts: chronic pulmonary disease
- Immunocompromised pts: T-cell deficiencies
Nocardia spp.
What bacterial species is associated with the following clinical presentation:
- Neonates: disseminated abscesses and granulomas in multiple organs, meningitis with septicemia
- Elderly: Influenza-like illness with or without gastroenteritis
- Pregnant women/pts with cell-mediated immune defects: bacteremia with hypotension and meningitis
L. monocytogenes
What are treatment and prevention options of Listeria monocytogenes infections?
- PCN or ampicillin +/- gentamycin
- Resistant to cephalosporins
- High risk ppl should avoid eating raw/partially cooked foods, soft cheeses, and unwashed fruits and veggies
What are possible treatment options for Nocardia spp?
Sulfonamides and proper wound care
