common tests: carbohydrates (one flashcard); staphylococcus

the fermentation of carbohydrates are commonly used to distinguish between certain bacteria, common examples are:

glucose, lactose, mannitol, maltose ←- we have, mannose

Staphylococcus Aureus:

• zoonotic

• characteristics: double-zone (Beta) hemolysis, opaque white or yellow colonies

• lab results: Maltose +, Mannitol +

• diseases associated with it: abscesses, mastitis (udder impetigo), Periorbital eczema, dermatitis, necrotizing endometritis (pigs), conjunctivitis, bumble foot (poultry), septicemia, arthritis

• organs: skin, mammary gland, joints, systemic

• treatment: Beta-lactams; watch for MRSA!

what is MRSA?

methicillin resistance staphylococcus aureus

Staphylococcus typically see skin when have this problem because of skin around the vulva)s pseudintermedius (previously called Staph. intermedius):

• Characteristics: 1-2 mm grey-white colonies, double hemolysis, lactose fermenting on purple agar

• lab results: Maltose weak +, Mannitol weak +, purple agar with maltose is used to differential Staph. Aureus from Staph Pseudintermedius

• diseases associated with it: dermatitis, pyoderma (most common cause), MRSP, pyometra, otitis externa

• organs: skin, ears, mammary, urinary/reproductive tract (with females typically see skin when have this problem because of skin around the vulva)

• treatment: culture + sensitivity; note MRSP; oxacillin is most used as the marker of methicillin resistance. cefoxitin can also be used

what does MRSP stand for?

methicillin resistance staphylococcus pseudintermedius

staphylococcus intermedius:

• characteristics: 2-4 mm opaque white colonies. double zone hemolysis

• lab results: G+ cocci in clusters (grape like); VP: -, lactose and mannitol: varied, maltose: + (maltose can be weak or negative in aerobic conditions)

• diseases associated with this: opportunistic wound infections (something else is happening in the body and it piggybacks on it, attacking the body more), cattle mastitis

• organs: skin, mammary gland, wounds

• treatment: culture-guided antibiotics; address biofilm on devices (inanimate objects is where it likes to “hang out”)

• **similar to Staph. pseudintermedius

staphylococcus hyicus:

• characteristics: 1-3 mm white opaque (non-pigmented),, non-hemolytic colonies (gamma)

• lab results: coagulase v, VP -, maltose -, mannitol -

• diseases associated with it: greasy pig disease (exudative epidermitis; build up on skin and this bacteria festers), septic polyarthritis, metritis/vaginitis, cattle mastitis, cutaneous infections

• organs: skin, systemic, mammary glands, urinary/reproductive tract

• treatment: early systemic/topical antibiotics; hygiene essentials

• NOTE** mainly just an issue in pigs

staphylococcus epidermidis:

• characteristics: 1-2 mm white opaque flat colonies; can be either non-hemolytic or hemolytic

• lab results: G+ cocci in clusters (grape like); coagulase -, MR+, trehalose - (we don’t do at NECC) *** NOTE: mannitol grows but does not ferment

• diseases associated with it: opportunistic wound infections, cattle mastitis

• organs: skin, mammary gland, wounds

• treatment: culture-guided antibiotics; address biofilm on devices

genus overview for Staphylococcus species:

• non-motile

• non-spore forming

• most are facultative anaerobes (can grow, ferment, and respirate in both but prefer anaerobic environments; so with the infections they burrow into the skin since there isn’t a lot of oxygen in deep skin)

• able to ferment sugars

• no growth on MacConkey agar (since MacConkey agars grow gram -)

• pyogenic bacteria (creation/development of purulent discharge- abscesses)

what should always be the first step when/before starting treatment?

do susceptibility testing

true/false: certain types of topical therapy can be effective for treatment of superficial infections.

true