Micobiology exam 2

What is the CAMP test?

Used to differentiate Strep species, positive result will yield an arrow shaped hemolytic zone due to completion of beta hemolyis initiated by S. aureus

if you have gram positive cocci you should perform a catalase test. If the test is positive what does this tell you

Its staphylococcus

if you have gram positive cocci you should perform a catalase test. If the test is negative what does this tell you

it is streptococci

layers of the skin

epidermis, dermis, subcutaneous tissue

how long does it take to completely regenerate the epidermis

one month

what is the dermis layer of skin

supports the epidermis and contains nerves, blood vessels, and lymphatic vessel penetration

What is the subcutaneous layer?

tubules of swear glands and hair follicles that traverse the dermis and epidermis ending in the subcutaneous layer

hair follicles

penetrate the epidermis to the subcutaneous layer

sebaceous glands

produce an oily secretion called sebum that keeps skin soft and water repellent

what two conditions cause acne

excessive secretion of sebum by sebaceous glands and excessive growth of propionibacterium acnes which colonizes hair follicles

Family Micrococcaceae

staphylococcus, micrococcus, somatococcus, and planococcus, all are aerobic so they can function with or without oxygen, all are gram positive cocci, catalase positive, and naturally found on the skin and mucous membranes

staphylococcus characteristics

normal flora, frequently found as pathogens in humans, fermenters of carbohydrates, NaCl tolerant

what is the only clinically significant Staph that is coagulase positive

staph aureus

Folliculitis

infection of a hair follicle by staphylococcus aureus

Hot tub folliculitis

not causes by staph aureus but is caused by Pseudomonas aureginosa and it is contracted from hot tubs, whirlpools, and pools with inadequate chlorine levels

furuncle

infection of the pilosebaceous unit and more excessive than folliculitis because the infection also involves a sebaceous gland

carbuncle

multiple furuncles grouped together. tend to occur in areas of thicker skin like the neck, back or thighs

what can staph aureus cause

fulliculitis, furuncle, carbuncle, pneumonia, food poisoning, pseudomembranous enterocolitis which cuts down the intestinal normal flora and this causes staph to overgrow and cause abcesses in the bowls, and scaled skin sydrome (staph secreted an exotoxin that causes the skin to peel and this normally occurs in newborns, toxic shock syndrome (staph secretes exotoxin TSST-1)

symptoms of toxic shock syndrome

fever, rash, skin peeling, low blood pressure and this can be prevented by using lowest absorbency tampons and changing tampons frequently

mrsa

methicillin resistant staph aureus

pathogenesis of staph aureus

has a capsule that prevents white blood cells from engulfing bacteria and the cells wall has an increased amount of peptidoglycan

staph aureus exotoxin

exfoliating-cause skin sloughing leukocidins- kills white blood cells TSST-1-toxic shock syndrome enterotoxins- exotoxins that act in the gut and are associated with staph food poisoning and pseudomembraneous enterocolitis

how do you identify staph aureus

opaque or white in color, medium to large colonies, normally beta hemolytic, gram positive cocci, facultative anaerobe, catalase positive, coagulase positive

what is coagulase negative staph

staphylococcus epidermidis which is found normally on the skin, fair follicles, and mucous membranes can be caused by invasion of foreign bodies such as shunts, catheters, prosthetic devices, and heart valves ,

characteristics of staphylococcus coagulase negative

white and nonhemolytic

Staphylococcus epidermidis characteristics

coagulase negative, white, non hemolytic, round, slightly raised, catalase negative, coagulase negative, DNase negative and novobiocin sensitive

Staphylococcus saprophyticus characteristics

coagulase negative, white, non hemolytic, round, slightly raised, catalase negative, coagulase negative, DNase negative, and novobiocin resistant

if you have gram positive cocci and perform a catalase test and it is positive what test should you perform next and what does this tell you

coagulase test and if this test is positive is is staph aureus and if it is negative you have staph epidermidis

what color are gram positive cocci

purple

what is streptococci

a chain of gram positive cocci, facultative anaerobes, catalase negative, normal flora on the skin, mucous membrane, mouth, pharynx, and urogenital

What is whatha hemolysis?

partial hemolysis of red blood cells and a greenish discolorization

What is beta hemolysis?

complete lysis of red blood cells and a clearing of the agar around the colonies

What is gama hemolysis?

no lysis of the red blood cells and no change in agar around the colonies

what is group a streptococcus

Streptococcus pyogenes that causes step throat, tonsillitis, erysipelas, impetigo, septicemia, pneumonia, necrotizing fasciitis

what strain of streptococcus is almost uniformly sensitive to bacitracin

streptococcus pyogenes

Impetigo

common among kids, blisters and sores around the face, neck, hands, and diaper area. contagious and is caused by staphylococcus aureus or streptococcus pyogenes

what are signs of a bacterial infection when looking in someone's mouth

swollen uvula, white spots, red swollen tonsils, throat tenderness, and a gray furry tongue

what are signs of a viral infection when looking in someone's mouth

red swollen tonsils, throat redness

what is scarlet fever

when the tongue has a whitish coating and appears swollen. The tongue has a strawberry appearance

What is necrotizing fasciitis?

flesh eating bacteria

what bacteria does 25 percent of pregnant women carry in their body

streptococcus agalactiae

streptococcus pneumonia characteristics

aplha hemolytic optochin sensitive and bile soluble

streptococcus viridans characteristics

alpha hemolytic optochin resistant and not bile soluble

streptococcus pyogenes characteristics

beta hemolytic bacitracin sensitive

streptococcus agalactiae characteristics

beta hemolytic bacitracin resistant

what does streptococcus agalactiae cause

meningitis or septicemia in newborns, infections in post parts women, femal urogenital tract infections, wound and skin infections

what are the characteristics of the enterococcus species

group D, can have an alpha, betta, or gamma reaction but most of the time is a gamma reaction, it is found in the normal intestinal flora, found in wounds, endocarditis, and UTIs

what are gram positive cocci that often occur in pains or short chains

enterococcus species

what is susceptible to penicillin low

enterococcus species

how do you identify enterococcus species

by performing a bile esculin test and a salt broth test and if the results are both positive it is in the enterococcus species

a blackened medium when performing a test with 6.5% salt broth means what

a positive result

streptococcus bovis and streptococcus equinus characteristics (group D strep)

susceptible to penicillin and it can be identified by a positive bile esculin test and a negative salt broth

streptococcus pnemoniae characteristics

gram positive cocci in pairs, found in the mouth and pharynx, need an increase in CO2 for better growth, alpha hemolytic

infections caused by streptococcus pnemoniae

pneumonia, meningitis, septicemia, pericarditis, pleuritis, otis media, sinusitis

how do you identify streptococcus pnemoniae

alpha hemolysis and susceptible to p/ optochin disk

Enterobacteriaceae characteristics

gram negative rods, aerobic and facultative anaerobes, ferment glucose, oxidase negative , non spore forming

What is MacConkey agar?

contains bile salta and crystal violet to inhibit gram positive cocci, contains lactose and neutral red dye as a ph indicator, lactose fermenters produce pink color and a lactose nonfermenters produces clear or yellow color

What is MacConkey agar used for?

isolation of gram negative bacteria and differentiates lactose fermenters or lactose non fermenters gram negative bacteria

Indole test results

positive if it forms a red ring at the surface of broth and if it is negative no red ring is formed

Methyl Red Test

Measures the production of mixed acids by fermentation of glucose a positive test is red and a negative test Is yellow or orange color

Voges-Proskauer Test

designed for organisms that are able to ferment glucose, but quickly convert their acid products to acetoin and 2,3-butanediol; produces a red color

Citrate Test

Used to determine the ability of an organism to use citrate as its sole source of carbon. Green result is a neutral Ph so it is negative and blue result is a basic is a basic ph which is positive

how do you indicate if it is in the enterobacteriaceae family

perform the IMViC test indole+,MR+,VP-,Citrate-

what detects wether a bacteria processes the enzyme urease

urea agar, it breaks down urea into ammonia and carbon dioxide it turns pink in basic conditions and it positive and is negative if it does not turn pink

What is Kligler's iron agar?

detects the fermentation of glucose and lactose, the production of hydrogen sulfide and carbon dioxide

in KIA agar when is the tube red/yellow

for glucose fermenters only

in KIA agar when is the tube yellow/yellow

for both glucose and lactose fermenters

Phenol Red Broth

acid production from fermentation of carbohydrate lowers pH below neutral range of indicator and turns the medium yellow; raising the pH turns the broth pink; gas production (from fermentation) is indicated by the bubble in the Durham tube

what are the two types of diarrhea

toxigenic and invasive

Escherichieae

e coli, can ferment lactose, can cause sepsis, endotoxin induced shock, urinary and wound infections, pneumonia in immunocompromised patients and meningitis in neonates

enteritis

inflammation of the intestine

Exterotoxigenic E. Coli

produces an enterotoxin that causes a secretory diarrhea

Traveler's diarrhea

travelers encounter a bacteria that the local population have developed immunity to. symptoms occur 5 to 15 days after and the bacteria must attach to the surface of the intestinal epithelial cels for toxin production to occur

Enteropathogenic E. coli (EPEC) (invasive)

pathogenesis is unclear and can cause diarrheal syndromes mostly in children. the inflammatory reaction to break down intestinal epithelium

Enteroinvasive E. coli (EIEC) (invasive)

feces contain blood, mucus , and white blood cells. the bacteria penetrates the intestinal epithelial cells causing inflammatory diarrhea

Enterohemorrhagic E. coli (toxigenic)

produces bloody diarrhea due to toxin damage of epithelial cells and is associated with to syndromes hemorrhagic colitis and hemolytic uremic syndrome

Hemorrhagic colitis

Abdominal cramps and bloody diarrhea, without fever, no fever or wbc in stool

Hemolytic Uremic Syndrome

leading cause of renal failure in children and present with diarrheal lines becomes bloody, only type of e coli that is sorbitol negative and this is clear on a MacConkey agar plate

all coli is what color on a macConkey agar plate except for enterohemorrhagic e coli

pink

Shigella characteristics

does not ferment lactose, fecal to oral route, associated with careless sanitation, malnutrition, and crowding, toxigenic

symptoms of the illness shigellosis

endotoxin causes fever and enterotoxin causes inflammation and degeneration of the intestinal wall, increased fluid loss, fever, watery diarrhea, abdominal cramping, muscle pain

S. sonnei

Most common shigella in the US

S. dysenteriae

shiga toxin. primarily interferes w/60s ribosome. inhibits eukaryote protein sythenesis. less common

Shiga toxin

neurological symptoms and coma due to shigella

what is the most communicable of bacterial diarrhea

shigella

Edwardsielleae characteristics

main reservoirs in nature are reptiles and freshwater fish, do not ferment lactose, has a black butt of the test tube due to abundant hydrogen sulfide, often related to aquatic accidents, not known to cause diarrhea

Salmonella characteristics

does not ferment lactose and produces a small amount of hydrogen sulfide, infections are caused by ingesting food, water or milk contaminated by human or animal secretion, primarily a pathogen of poultry, cows, pigs, and pets

Typhoid Mary

A cook who carried typhoid fever and passed it on to many people in and around New York City in the early 20th century.

clinical types of salmonella

gastroenteritis- most common and causes mild to severe diarrhea with a low grade fever and vomiting or nausea septicemia- high fever and positive blood cultures enteric fever- mild fever and diarrhea carrier state- person with previous infection may continue to excrete the bacteria in their feces

citrobactereae characteristics

natural habitat is in soil, water and human feces, can cause a UTI and septicemia in debilitated patients and is associated with meningitis and brain accesses in neonates

Klebsiella characteristics

large colonies of mucoid consistency, lactose and glucose positive, widely distributes in nature and in the gastrointestinal tracts of humans and animals

Klebsiella pneumoniae

causes lung infections in patients with debilitating conditions like alcoholism, diabetes, and pneumonia

Enterobacter characteristics

widely distributed in water, sewage, soil and on vegetables and it can cause a UTI, respiratory tract infection, cutaneous wounds infections and occasionally septicemia and meningitis

Serratia characteristics

occurs in soil and water and is in the normal flora of the intestines, intense red pigment, it can cause pneumonia and septicemia in patients receiving chemotherapy, opportunist and found in burn and wound patients

Proteus characteristics

found in soil, water, and fecal contaminated materials, spreads rapidly. Can cause UTI, wound infections

Morganella Characteristics

can cause a UTI, wound infections and can cause Diarrhea

Providencia Characteristics

can be recovered from feces and cause a UTI

Yersinia characteristics

y. pestis- found on rodents like rats and squirrels, transferred from rodent to rodent or rodent to human by a rat flea. three forms like the bubonic plague, septicemic plague, or pneumonic plague

Bubonic Plague

caused by the bacteria from a flea bite, causes inflammatory swelling of the lymph in the groin. the incubation period is 2-8 days ending with a fever, chills headaches, weakness and tenderness

Septicemic plague

when the bubonic plague progresses to a massive bacterial growth in the blood and initiates the clotting mechanism.