Chapter 2: Medically Relevant Bacteria Flashcards
Bacteremia
bacteria in bloodstream without overt clinical signs
Septicemia
bacteria in bloodstream (multiplying) with clinical symptoms
What medically relevant organisms commonly reside in the blood?
none, generally sterile
What are medically relevant organisms that are found at cutaneous surfaces including urethra and outer ear?
Staphylococcus epidermidis
What are some medically relevant organisms that commonly reside in the nose?
staphylococcus aureus
Some medically relevant organisms that reside in the oropharynx?
Viridans streptococci including Streptococcus mutans
How does Streptococcus mutans produce dental plaque?
secretes a biofilm that glues it and other oral flora to teeth producing dental plaque
What are some less common but notable organisms found in the oropharynx?
Assorted streptococci, nonpathogenic Neisseria, nontypeable Haemophilus influenzae, Candida Albicans
What does nontypeable Haemophilus mean?
Haemophilus that has no capsule
What are some medically relevant organisms that are found in gingival crevices?
Anaerobes: Bacteroides, Prevotella, Fusobacterium, Streptococcus, Actinomyces
What are some medically relevant organisms that are found in the stomach?
none
What are some common or medically relevant organisms that reside in the colon?
microaerophilic/ anaerobic
Babies: breast fed only
Bifidobacterium
Adult:
Bacteroides/ Prevotella
(predominant organism)
Escherichia
Bifidobacterium
What are some less common but notable organisms that can be found in the colon in babies?
lactobacillus, streptococci
What are some medically relevant organisms that reside in the vagina?
lactobacillus
What organisms colonize the vagina of 15-20% of women and may infect the infant during labor or delivery, causing septicemia and/or meningitis? What organism may infect the neonate from fecal flora?
Group B Streptococcus
E. coli from fecal
Characteristics of obligate aerobes?
- require oxygen
- have no fermentative pathways
- generally produce superoxide dismutase
Important genera found to be obligate aerobes?
- mycobacterium
- pseudomonas (bacillus)
What are characteristics of microaerophilic organisms?
require low but not full oxygen tension
What are some important genera considered microaerophilic organisms?
- Campylobacter
- Helicobacter
Characteristics of facultative anaerobes?
Will respire aerobically until oxygen is depleted and then ferment
Important genera of facultative anaerobes?
most bacteria, e.g., Enterobacteriaceae
What are some important characteristics to remember about obligate anaerobes?
- lack superoxide dismutase
- generally lack catalase
- are fermenters
- cannot use O2 as terminal electron acceptor
What are some genera that are considered obligate anaerobes?
- Actinomyces
- Bacteroides
- Clostridium
How do you remember some of the most important obligate anaerobes?
ABC’s
- Actinomyces
- Bacteroides
- Clostridium
What color do Gram + organisms stain? Why?
purple/blue
Have large peptidoglycan layer so can absorb crystal violet better
What color do Gram (-) bacteria turn with gram stain? Why?
red/ pink
peptidoglycan layer is not as large so won’t absorb crystal violet as well
What color do acid fast organisms stain?
red
What color do non-acid fast bacteria stain?
blue
Another name for acid fast stain?
Ziehl-Neelson or Kinyoun stain
All cocci are Gram negative or Gram positive with what exceptions?
Gram-positive with the exception of Neisseria, Moraxella, and Veillonella
All spore formers are Gram negative or Gram positive?
Gram positive
Background in stains modified for tissue will be what color?
red
What are 2 protozoan parasites that have acid fast oocysts?
Cryptosporidium and Isospora
List Gram negative cocci bacteria.
- Neisseria
- Moraxella
- Veillonella
List major groups of Gram negative rods.
rods, curved or helical, enterobacteriaceae, anaerobic rods, gram-variable rods, spirochetes
List gram negative rods.
- Pseudomonas
- Burkholderia
- Acinetobacter
- Eikenella
- Kingella
- Haemophilus
- Bartonella
- Legionella
- Brucella
- Bordetella
- Francisella
- Capnocytophaga
- Pasteurella
List gram negative curved or helical rods.
- Campylobacter
- Helicobacter
- Vibrio
List the organisms of the enterobacteriaceae family.
- Escherichia
- Shigella
- Salmonnella
- Klebsiella
- Proteus
- Yersinia
- Aeromonas
- Serratia
- Citrobacter
- Enterobacter
List the organisms considered gram negative anaerobic rods?
- Bacteroides
- Prevotella
- Porphyromonas
- Fusobacterium
List the gram-variable rods.
- Gardnerella
- Mobiluncus
List the spirochetes.
- Treponema
- Borrelia
- Leptospira
List the Gram positive cocci.
Staphylococcus
Streptococcus
Enterococcus
List the types of Gram positive rods (groups)?
- aerobic or facultative anaerobic
- anaerobic
What are the aerobic or facultative anaerobic gram positive rods?
- bacillus
- listeria
- corynebacterium
- nocardia
- mycobacterium
What are the anaeorbic gram positive rods?
- clostridium
- actinomyces
- propionibacterium
- lactobacillus
Gram + spore formers?
Clostridium
Bacillus
What are 3 classes of non- Gram- staining bacteria?
- Mycoplasmataceae
- Rickettsiaceae
- Chlamydiaceae
What are the organisms found in the Mycoplasmataceae family?
- Mycoplasma
- Ureaplamsa
What are some organisms found in the Rickettsiaceae family?
- Rickettsia
- Ehrlichia
- Coxiella
What are some organisms found in the Chlamydiaceae family?
- Chlamydia
- Chlamydophila
Why does mycobacterium not stain well with gram stain? What is it technically considered (Gram negative or positive)
Waxy cell wall does not work well with gram stain; considered gram positive
What organisms are so thin that the color of gram stain cannot be seen and are organisms that are all considered gram negative?
spirochetes, chlamydiae, and rickettsias
What organisms that is Gram negative, does not stain well with traditional gram stain unless counterstain in increased?
Legionella
