Micrococcaceae
This species of Staphylococcus is most notable as a cause of UTI
What is Staphylococcus saprophyticus
Review:
This species is differentiated from S. epidermidis by using the novobiocin test; it is resistant while S. epidermidis is susceptible.
Bad for babies
What is group B strep/S. agalactiae
Review
Beta hemolytic
Can give babies meningitis, sepsis, pneumonia, fever, and hypotension
Can give adults skin and wound infections, UTIs, and mastitis
Identified with CAMP test and hippurate
A bacteria that forms spores, contaminates rice, and causes food poisoning due to the release of bacterial toxins
What is B. cereus
Review
Best detected by toxin assay in stool
Other bacillus species (outside anthracis) include B. stearothermophilus (used in QC) and B. subtilis (education)
Specimens for bacillus include blood, sputum, wound swaps, and stool
All bacillus are catalase positive
This microscopic observation occurs when Gardenerella covers squamous epithelial cells
What is a clue cell?
Review
Gardenerella can be normal flora in female vaginal tract and male distal urethra, but can also cause bacterial vaginosis
Rarely can cause UTI and sepsis
Linked to premature rupture of amniotic membranes
V agar can be used to bring this out from normal flora, and it is beta hemolytic
Grows slow (48hrs) and likes body temp and increased CO2
This agar contains crystal violet and bile salts, which inhibits the growth of gram positives
What is macconkey's agar
Review
Also tracks lactose fermentation, so the agar turns pink if fermentation occurs and is yellow if it doesn't
This S. aureus virulence factor is responsible for toxic shock syndrome
What is TSST-1
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This is considered an exotoxin, along with exfoliatins, and enterotoxins; enterotoxins (entero meaning intestine) are responsible for food poisoning and symptoms appear 4-6 hours after ingestion. Exfoliatin is responsible for scalded skin syndrome.
The species which cannot grow without vitamin B6 in the media
What is Abiotrophia
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This is low pathogenicity like Aerococcus
Normal flora
Alpha and gamma hemolytic
A catch-all name for contaminant Corynebacteriums
What are diphtheroids
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Most members are normal flora, hence the contamination catch-all
C. diphtheriae is pathogenic and is transmitted through aerosols or touch. Exotoxins are produced, leading to respiratory issues (mainly pseudomembrane), cardiac (and kidney) issues, and cutaneous issues.
Vaccines have nearly irradicated this disease
When gram stained, they appear as pleomorphic rods with clubbed ends in palisades or chinese letters
This bacteria shows a bottlebrush pattern, produces H2S in TSI, and is found particularly in pigs
What is Erysipelothrix
Review
When humans are infected, it is considered a zoonosis and the disease is called erysipeloid.
It enters through the skin and causes issues related to it including lesions, then spreads causing bacteremia and cellulitis
Prefers increased CO2 for growth
It can appear as a short rod or filamentous rod
The medium which is used to promote the production of metachromatic granules for C. diphtheriae
What is Loeffler's medium?
Review
When looking at these bacteria under the microscope, they must be stained with methylene blue to see the metachromatic granules
Cysteine tellurite agar can be used, as the bacteria hydrolyzes the tellurite on the agar to form black colonies
Modified Tinsdale agar is similar as black colonies are also formed by C. dipth, but a brown halo also appears
This species is a strict aerobe that rarely causes infections
What is micrococcus
Review:
Sensitive to bacitracin
Glucose nonfermenter
Resistant to furizolidone
Microdase positive
It is only necessary to ID this from staph if isolated from a sterile area such as blood or CSF
The strain of Enterococcus that mainly causes nosocomial infections
What is vancomycin resistant enterococcus
Review:
Typically alpha or gamma, but can be beta hemolytic
Weakly catalase positive
Enterococcus is always resistant to penicillin, similar to almost all S. aureus
More common in chronically ill patients
Treated with quinupristin and dalfopristin (synercid), but it can be lethal
The bacteria which is easily treated in early stages with penicillin and has four ways it presents/infects
What is B. anthrasis
Review
Cutaneous infection is the majority and occurs when endospores enter openings in the skin and produce eschars (20% mortality if dissemination occurs)
GI infection is rare and occurs through oral or oropharyngeal transmission. There is significant mortality due to toxemia or sepsis. 25-50% mortality rate.
Inhalation (Woolsorter's) occurs when endospores are inhaled after being exposed to animals. It spreads to the lymph nodes before becoming systematic. Almost always fatal in 1-2 days.
Injectional is associated with contaminated drugs of abuse and there is no eschar. Presents as severe soft tissue infection then turns into septic shock.
A species of bacteria which is similar to group A strep, as it causes pharyngitis
What is Arcanobacterium hemolyticum
Review
Can differentiate from group A strep through gram staining, lack of agglutination for latex test, and is PYR negative
Is catalase negative
A media that is selective and differential for Staph species and is selective for Gram positives
What is mannitol salt agar
Review
Colonies that can ferment mannitol turn the agar yellow (S. aureus) and colonies that cannot keep the agar pink
The enzyme that is responsible for clots autolyzing during the tube coagulase test
What is staphylokinase
Review:
Slide coagulase detects bound coagulase/clumping factor
Tube coagulase detects free coagulase
Latex coagulase detects clumping factor and protein A
One of S. pneumoniae's virulence factors that produces holes in cell membranes, causing lysis
What is pneumolysin?
Review
S. pneumoniae is an alpha hemolytic bacteria that presents as diplococci
It has a polysaccharide capsule and phosphorylcholine, which is used to adhere to cell receptors
Causes primary pneumonia and is the leading cause of bacterial meningitis
Also causes sepsis, sinusitis, and otitis media
The bacteria which is catalase positive, showcases tumbling motility, is hippurate positive, esculin positive, and CAMP positive.
What is Listeria monocytogenes
Review
Need to send to health department
It looks a lot like group B strep and is also bad for babies! (small white to grey colonies with narrow zone of beta hemolysis)
Cold-enrichment technique is used to recover from food samples
Taken from blood, CSF, amniotic fluid, placenta tissue, or food samples
Travels from GI tract to meninges and blood
Causes sepsis and meningitis in immunocompromised
A species of bacteria that have round, mucoid colonies that are salmon-pink to coral. They also grow in 4-7 days.
What is Rhodococcus
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This is primarily a horse pathogen that rarely affects humans. When it does, it causes pneumonia, bacteremia, skin lesions, and peritonitis
It is weakly acid fast
This media is used to grow very fastidious bacteria that will not grow on sheep blood agar
Chocolate agar
Review
H. influenzae and N. gonorrhea
A virulence factor that S. aureus has that interferes w/antibody activation and phagocytosis
Protein A
Review
Alpha beta gamma and delta toxins attack host membranes which leads to destruction
Clumping factor, coagulase, and hyaluronidase enhance invasion and spread
Catalase inactivates free radicals in phagolysosomes
Conditions patients exhibit (ex. rheumatic fever) after having a streptococcal infection
What are poststreptococcal sequelae?
Review
The body attacks itself because self-antigen is similar to the antigen on the bacteria, which antibodies are made in response to
The body can make antibodies to streptolysin O, DNaseB, streptokinase, and hyaluronidase
Primarily caused by S. pyogenes
S. pyogenes (Group A) is mainly known for pharyngitis, but can also cause skin infections and scarlet fever (think pyrogenic exotoxins)
The immunodiffusion test that is used to demonstrate toxin production by C. diphth
ELEK test
Review
Issues from this bacteria are mainly caused by the production of exotoxins, which are acquired by incorporation of phage genes into the bacteria
Because of this, treatment includes antibiotics and antitoxins, but also prophylactics should be used for others who are exposed
N. brasiliensis creates this invasive skin lesion, which has a yellowish drainage due to sulfur granules
What is a mycetoma
Review
Examining the sulfur granules will reveal branching gram positive rods
N. brasiliensis can cause other skin infections such as lymphocutaneous infections, cellulitis, and hematogenous dissemination
Nocardia is acid fast, and AFB stains are used to differentiate it from streptomyces
A general type of media that supports bacterial cells but discourages log growth. Some examples include nutrient agar and tryptic soy agar.
What is maintenance media?