Gram Positive

Question 1

S. Aereus

Answer 1

Coccus, irregular clusters

Characteristics- Non-motile, facultative anaerobes, coagulase and catalase positive, contact transmission

Infectious Dose: hundreds

Virulence Factors- Evade phagocytosis with coagulase. Betalactamase(exotoxin)

Diseases-1. Food poisoning 2. Colitis-cramps, diarrhea, and fever. 3. IMPETIGO-skin blist r 4. Scalded-skin syndrome 5. Toxic Shock syndrome bacteremia

Treatment-Methicillins, vancomysin for MRSA

Question 2

S. Pyogenes

Answer 2

Coccus, pairs or chains

Characteristics- Form white colonies on blood agar plate, Beta-Hemolysis, more common in children

Virulence factors-CAPSULE, Protien M, Pyrogenic toxins stimulate helper T cells to release cytokines.

Diseases- Pharyngitis(strep), scarlet fever(red chest), Pyoderma(impetigo-pus), Erysepelas(swollen lymph nodes), TSS, Necrotizing fasciatis, Rheumatic fever on second reaction, Glomerulonephritis

Treatment-Penicillin G.

Question 3

S.pneumonie

Answer 3

Coccus, mainly pairs

Characterisicts-In mouth and pharynx, becomes harmful in lungs, more common in kids and elderly

Virulence Factors-
Polysaccharide capsule, Protein adhesin, sIgA protease, Pneumolysin-binds cholesterol and bursts cell

Diseases-Pneumococcal PNEUMONIA, Sinusitis and otitis media-sinus or ear infection, bacteremia and endocarditis, Pneumococcal memingitis

Treatment-Penicillin or Cephalosporins. Vaccines-Pneumovax 23 or PCV

Question 4

Viridians Strep

Answer 4

Coccus

Characteristics-Alpha hemolysis, LACK group-specific carbs–not grouped by Lancefield, major role in dental caries and plaque

Disease-Caries, Plaque, and meningitis or endocarditis if in blood

Question 5

B. anthracis

Answer 5

Bacillus, single, diplo, or strepto

Characteristics-Non-motile, Transmitted to animals or humans via inhalation, inoculation thru skin break, ingestiion

Virulence Factors-Form ENDOSPORES, 3-component toxin and protein capsule

Diseases-1. Inhalation (woolsorter’s disease)-capillary thrombosis and cardiovascular shock; 2.Gastrointestinal-spore-contaminated meat, rare but serious; 3.Cutaneous-eschar (black, necrotic) skin lesions

Treatment-Ciproflaxacin, penicillin, tetracycline-early detection crucial, vaccine-multiple doses and boosters

Question 6

C.perfringes

Answer 6

Bacillus

Characteristics-Anaerobic, In soil, water, and GI tract, Types A-E, A is #1

Virulence Factors-Form ENDOSPORES, 11 toxins

Diseases-Food poisoning-enterotoxin leads to abdominal cramps and watery diarrhea; Gas gangrene-endospores enter due to trauma, crepitance

Treatment-Food poisoning is self-limited; Gas gangrene-remove dead tissue, penicillin and hyperbaric Oxygen

Question 7

C. difficile

Answer 7

Bacillus

Characteristics-Normal intestinal flora, opportunistic

Virulence Factors-SPORES

Diseases-Self-limiting explosive diarrhea, serious cases lead to pseudomembranous colitis-discontinuing antimicrobials

Treatment-Broad-spectrum AB’s

Question 8

C.botulinum

Answer 8

Bacillus (MOST POTENT POISON KNOWN)

Characteristics-Toxin leads to flaccid paralysis, infant botulism from honey, toxin is heat-sensitive

Virulence Factors-SPORES, toxins

Disease-Food-borne botulism- canned food or preserved fish, progressive paralysis; Infant botulism-ingestion of endospores which thrive due to lack of normal flora; wound botulism-same as food-borne

Treatment-Polyvalent antitoxin, antimicrobial drugs for infants

Question 9

C. tetani

Answer 9

Bacillus

Characteristics-Obligate anaerobe, in soil, dust, and GI tract, spastic paralysis

Virulence Factors-SPORES grow in anaerobic wound, toxins

Disease-Tetanus-spasms and contractions, can’t exhale

Question 10

L.monocygenes

Answer 10

Coccobacillus

Characteristics-Soil, water, mammals, birds, fish, and insect, no toxins or enzymes

Virulence Factors-Avoids Immune System by breaking out of lysozome; grows in cold temps

Disease- 3rd trimester still births

Treatment-Ampicillin

Question 11

C.diphteriae

Answer 11

Characteristics-Plants and animals, skin, respiratory tract, gastrointestinal, urinary, and genital tract

Virulence factors-Toxin

Disease-Diptheria-toxin, pseudomembrane in respiratory passages or skin

Treatment-Antitoxin, penicillin or erythromycin, vaccine

Question 12

Propionibacterium

Answer 12

Small Bacillus

Acnes-most common in human infections
cillus

ACNE

Question 13

Actinomyces

Answer 13

Characteristics-Anearobe, filamentuous

DENTAL PLAQUE,

Treatment-Amoxicillin

Question 14

Nocardia

Answer 14

Bacillus Positive to Acid-Fast

Characteristics-Saprophyte(dead tissue)

Disease-Nocardiasis(pulmonary extension), TB-like pulmonary disease

Question 15

M. Tuberculosis

Answer 15

Acid Fast

Characteristics-Resistant to AB, disinfectants, etc. due to acid-fast cell wall

Diseases-Tuberculosis-infection of lungs-caseous necrosis, diagnosed using stethoscope, x-rays (cloudiness), and skin test using PPD

Treatment-Difficult due to slow growth and survival inside macrophage, combination and long-term drug, INH and Rifampin, MDR strains are much more expensive-Cipro and kanamycin, Vaccine-BCG

Question 16

M. Leprae

Answer 16

Acid Fast

Characteristics-Resistant to AB, disinfectants, etc. due to acid-fast cell wall

Virulence-CANT BE CULTIVATED IN VITRO, associated with mice and armadillos, long incubation period

Diseases-2 forms of leprosy: Tuberculoid-High cell-mediated, low antibody responses, Nonprogressive, loss of sensation in regions of skin; Lepromatous- low cell-mediated, high antibody, gradual tissue destruction–loss of facial features, digits, etc…

Treatment-Tuberculoid form: dapsone and rifampin for 6 mo.; Lepromatous form: dapsone, rifampin, and clofazimine for 2 yrs, then dapsone for 10 years

Question 17

M. ulcerans

Answer 17

Acid Fast

Virulence Factors-Associated with slow-moving water, Mycolactone toxin destroys subcutaneous tissue and is immunosuppressant.

Diseases-Skin Disease called BERULI ULCER, skin falls off exposing subcutaneous ulcer.

Treatment-Excise skin and use graft