Exam 1 review sheet Flashcards
What is the arrangement of Staphylococci bacteria?
Grape-like Clusters
What are the characteristics of Staphylococcus aureus?
- Gram-positive cocci in clusters
- Facultative anaerobe
- Catalase positive
- Coagulase positive
- Resistant to environmental stress
- Non Motile
What is the habitat of Staphylococcus aureus?
Nose and Skin
What is the Mode of Transmission of Staphylococcus aureus?
Contact
Is Staphylococcus aureus Coagulase positive or negative?
Positive
What diseases do Staphylococcus aureus cause?
- Folliculitis
- Impetigo
- Acute Endocarditis
- Food poisoning (Toxin)
- Osteomyelitis
- Scalded Skin Syndrome (Exfoliatin toxin, dissolution of epidermal
desmosomes) - Wound infection
- Toxic shock syndrome (Toxic shock syndrome toxin
What are the characteristics of Staphylococcus epidermis?
- Gram-positive cocci in clusters
- Catalase positive
- Coagulase negative
What is the Habitat of Staphylococcus epidermis?
Normal flora of skin and mucous membrane
What is the Mode of Transmission of Staphylococcus epidermis?
Person to person
What diseases do Staphylococcus epidermis cause?
- Subacute bacterial endocarditis on prosthetic heart valves
- UTI - Urinary Tract Infection
What are the characteristics of Staphylococcus saprophyticus?
- Gram-positive cocci in clusters
- Coagulase negative
- Resistant to novobiocin
What diseases do Staphylococcus saprophyticus cause?
- Urinary Tract Infection
- Causes Cystitis; Bacteriuria, hematuria, pyuria
- Organism is the causative agent in 10-20% of urinary tract
infections in sexually active, young women
What is Cystitis?
Inflammation of the urinary bladder and ureters
What is Bacteriuria?
Presence of Bacteria in the urine
What is Hematuria?
The presence of blood in the urine
What is pyuria?
The presence of white blood cells in the urine
What is a nosocomial infection?
Hospital acquired infection
What Staphylococci are resistant to Methicillin?
Staphylococcus aureus
What is the cause of nosocomial infections in many parts of the world?
-MRSA
These strains are currently a significant cause of nosocomial infections
(hospital acquired infections) in many parts of the world
What is hemolysis?
Breakdown of the red blood cell membrane
What media should be examined for hemolysis?
Sheep blood Agar
What is hemolysin?
Any substance that can cause lysis (destruction) of erythrocytes (RBC’s) and
the release of their hemoglobin
What is Alpha hemolysis and provide some examples?
Alpha hemolysis is incomplete hemolysis exhibiting a olive green to brown
color
Examples: S. pneumoniae and Viridans (S. mutans, S. mitts, and S. salivarius)
What is Beta hemolysis and provide some examples?
Beta-hemolysis is complete hemolysis
Examples: Streptococcus pyogenes and Streptococcus agalactiae
What is Gamma hemolysis?
Gamma-hemolysis is no hemolysis.
Examples: Enterococcus species
Rebecca Lancefield - produced Lancefield Classification
- Group A = Streptococcus pyogenes
- Group B = Streptococcus agalactiae
- Group D = Enterococcus faecalis, E. faecium
What bacteria is group A - Beta hemolytic Streptococcus?
Streptococcus pyogenes
What bacteria is group B - Beta hemolytic Streptococcus?
Streptococcus agalactiae
What bacteria is group D - Beta hemolytic Streptococcus?
Enterococcus faecalis; E. faecium
What Streptococci can be resistant to vancomycin?
Enterococcus
What is the Habitat of Streptococcus pyogenes?
Human throat and skin
What is the Mode of Transmission of Streptococcus pyogenes?
Respiratory Droplets
hat diseases do Streptococcus pyogenes cause (Group A Streptococci)?
- Strep throat
- Necrotizing fasciitis (flesh eating disease)
- Scarlet fever (pyrogenic erythrogenic toxin)
- Rheumatic fever
- Impetigo
- Erysipelas
- Cellulitis
- Glomerulonephritis
- Otitis media
- Sinusitis
- Toxic Shock Syndrome
What is necrotizing fasciitis?
flesh eating bacteria which causes rapid progressive tissue damage, severe
infection caused by Group A Strep. bacteria
What is Scarlet fever?
The complication of strep throat
What toxin is responsible for Scarlet fever
pyrogenic erythrogenic toxin
What is Erysipelas?
- Erysipelas is a type of cellulitis (skin infection) generally caused by Group A
Streptococci - The risk factor associated with this infection include local trauma (break in
the skin), skin ulceration, and impaired venous or lymphatic drainage. - Reddening of skin, distinct margin, swollen lymph nodes, pain, fever, chills,
and leukocytosis
What is Rheumatic fever?
- Complication of Strep Throat. It is an immune response. They cross react
with heart valves and cause damage - Definition: a severe disease chiefly of children and characterized by painful
inflammation of the joints and frequently damage to the heart valves
What is Cellulitis?
Inflammation of the cellular or connective tissue
What is Glomerulonephritis?
Inflammation of the glomeruli of the kidney
What is Otitis Media?
Middle ear infection
What is Sinusitis?
Inflammation of one of the paranasal sinuses
What is Toxic Shock Syndrome?
An acute infection characterized by high fever, a sunburn-like rash,
vomiting, and diarrhea, followed in severe cases by shock, that is caused by
Staphylococcus aureus and Streptococcus pyogenes
What are the Characteristics of Streptococcus agalactiae?
- Gram-positive in chains
- Beta hemolytic
- Catalase negative
- Hippurate hydrolysis positive
What Group of Streptococci does S. agalactiae belong to?
Group B Streptococci
What is the Habitat of Streptococcus agalactiae?
Human urogenital tract
What is the Mode of Transmission of Streptococcus agalactiae?
During Birth or sexual activity
What diseases can Streptococcus agalactiae cause?
Neonatal meningitis and septicemia
What are the Characteristics of Enterococcus faecalis?
- Gram-positive chains
- Catalase negative
- Gamma hemolytic
- PYR +
- BEM positive
- NaCl positive
What Group of Streptococci does Enterococcus faecalis belong to?
Group D Streptococci
What is the Habitat of Enterococcus faecalis?
Human Colon
Urethra and female genital tract
Are part of the normal intestinal flora
What diseases do Enterococcus faecalis cause?
Urinary Tract Infection
Wound infections Infection
Endocarditis rare but life-threatening
Bacteremia
What are the Characteristics of Streptococcus pneumoniae (non-
Lancefield)?
-Gram-positive cocci in elongated pairs (lancets) or short chains
-Alpha hemolytic
-Catalase negative
-Polysaccharide capsule (can be mucoid)
-85 serotypes based on antigenicity of polysaccharide capsule
-P-disk resistant
What is the Habitat of Streptococcus pneumoniae?
Human Upper Respiratory Tract
What is the Mode of Transmission of Streptococcus pneumoniae?
Respiratory Droplet
What diseases does Streptococcus pneumoniae cause?
Pneumonia (60%) and meningitis in adults
Otitis media and sinusitis in children
What are the Characteristics of Viridans group Streptococci?
Gram-positive in chains
Alpha hemolytic
BEM negative
NaCl negative
PYR negative
What is the Habitat of Viridans Group Streptococci?
Human Oropharynx (Oral Cavity)
What is the Mode of Transmission of Viridans Group Streptococci?
Bloodstream during dental procedure
What diseases does Viridans Group Streptococci cause?
Sub-acute bacterial endocarditis
Dental caries (S. mutans)
What does Streptococcus mutans cause?
Dental caries; AKA Dental cavities. It adheres to enamel of tooth and
ferments sugars to lactic acid which erodes teeth
What are some characteristics of Neisseria?
Gram-negative diplococci, inhabit mucous membranes, aerobic or
facultative anaerobes, and produce the enzyme cytochrome oxidase
What are 2 pathogenic species of Neisseria?
Neisseria meningitidis, Neisseria gonorrhoeae
Where is Neisseria meningitidis commonly found?
in the human nasopharynx
How is Neisseria meningitidis transmitted?
By respiratory droplets
How is Neisseria meningitidis spread?
In packed/crowded populations
How many serogroups of Neisseria meningitidis are there?
13 (determined by capsule)
What are the virulence factors of Neisseria meningitidis?
pili, transport, polysaccharide surface, protease, endotoxin, crosses to
meninges, inflammatory response in brain
What is the mortality rate of Neisseria meningitidis even with treatment?
5-15%
Which group of people has the highest the rate of Neisseria meningitidis?
children (6-24 months) young (11-21 years)
How do you diagnose Neisseria meningitidis in the lab?
Culture on special medium, differentiate by carbohydrate utilization test,
DNA probe tests, and serological tests
How do you treat Neisseria meningitidis?
prompt antibiotic usage
How do you prevent Neisseria meningitidis?
vaccines (2/4 in US)
What is the pathogenesis of Neisseria gonorrhoeae in the genital tract?
male: acute urethritis, discomfort, pain, discharge, dysuria, polyuria, or
asymptomatic
female: endocervical infection, rectal, pelvic pain, vaginal discharge, PID
What are some other infections of Neisseria gonorrho?
conjunctivitis, pharyngitis, septicemia, and meningitis
What are the virulence factors of Neisseria gonorrhoeae?
pili, transport, polysaccharide surface(antiphagocytic), protease(cleaves IgA
antibodies), endotoxin(DIC), antigenic variation
How do you diagnose Neisseria gonorrhoeae in the lab?
presumptive- intracellular G- diplococci in smears of urethral pus, NAA
What drugs are required by most states to be instilled into infants eyes to
prevent gonococcal infections?
Erythromycin or silver nitrate
What are the nonpathogenic Neisseria related species?
Saprophytic species
What Neisseria related species are Gram-negative diplococci / bacilli that
cause conjunctivitis, otitis media, sinusitis, respiratory infections?
Moraxella catarrhalis
-butyrate esterase positive
-carbohydrate utilization test - negative
Bacillus anthracis
red fluid filled lesion that eventually turns black and necrotic form bleeding
Corynebacterium jeikeium
chronic urinary tract infections, bacteremia, and wound infections in immunocompromised patients
Corynebacterium diptheriae
a pulmonary infection that commonly presents with fever, cough or chest pain. It can also present as pneumonia, lung abscesses, or cavitary lesions. Central nervous system symptoms include headaches, lethargy, confusion and seizures.
Gardnerella vaginalis
malodorous grayish vaginal discharge, presence of clue cells and increased vaginal pH usually greater than 4.5
