As a first step of gram staining we stain and smear the smear with methylene-blue for 3-5 min
False (with crystal violet)
Fixation of the smear is carried out with 96% ethanol during gram staining
True
Gram-positive bacteria stain red as a result of gram staining
False (stain pruple)
Lactobacillus are facultative pathogenic bacteria
False (not pathogenic)
We can differentiate staphylococci from streptococci on the base of oxidase production
False
We can differentiate micrococci from streptococci on the base of catalase production
False
Stranglers of horse is caused by streptococcus eqourum
False (caused by Streptococcus equi subsp. equi)
Morel disease is caused by Staphylococcus pesudointermedius
False (caused by Staphylococcus areus subsp. anaerobius)
Staphylococcus can tolerate high (up to 10%) NaCl conc.
True
Staphylococcus are more fastidious than Streptococci
False
Staphylococcus have capsule, but no flagella
False
Staphylococcus are non spore forming bacteria
True
Staphylococcus show active motility
False
Staphylococcus cannot grow on nutrient agar, they need blood agar
False
Streptococci are catalase neg. bacteria
True
Fixation of bacteria during gram staining is carried out with 96$ ethanol
True
Greasy pig disease is caused by Staphylococcus suis
False (caused by Streptococcus hyicus)
Stranglers of horses is caused by Staphylococcus equi
False (caused by Streptococcus equi subsp. equi)
Morel disease is caused by Streptococcus pyogenes
False (caused by Staphylococcus areus subsp. anaerobius)
Streptococcus have capsule, but no flagella
True
Staphylococcus
- Habitat
- Morphology
- Staining
1. Habitat: • skin, • mucous membrane, • food, plant, • soil, • water 2. Morphology: coccus, bunch of grape 3. Staining: Gram positive
Gram staining
- crystal violet: 3-5 minutes
- Lugol solution: 1-1.5 minutes
- 96% alcohol: some drops
- water
- fuchsin: 0.5-1 minutes
- water
- drying
Staphylococcus Culture
- Type of culture?
- Pigments?
- Haemolysis?
- Selective culture types?
- simple: nutrient agar, nutrient broth
- pigment: golden, white
- haemolysis:
- β haemolysis (in some sp double haemolysis)
- no haemolysis - selective culture:
- 10% NaCl – mannitol - phenol red agar,
- Na-tellurite – glycine - pyruvic acid – egg (Baird-Parker agar)
Staphylococcus Biochemistry:
- Catalase/oxidase?
- Fermentative?
- EC enzymes?
- Surface proteins?
- Toxins?
- Catalase: +, oxidase: -
- Fermentative
- Extracellular enzymes: coagulase, fibrinolysin, hyaluronidase…
- Surface proteins: Protein-A
- Toxins: haemolysins, leucocidins, enterotoxins, dermotoxin
Staphylococcus:
- Antigens
- Resistance
- Pathogenicity
- Antigens: complex
- Resistance: good
- Pathogenicity:
• local suppuration,
• abscesses,
• arthritis,
• mastitis,
• metritis,
• dermatitis
• septicaemia
Staphylococcus: Species: coagulase positive species 1. extracellular enzymes? 2. toxins? 3. haemolysis? 4. mannitol + or - ? 5. pathogens? 6. Species names?
- extracellular enzymes
- toxins
- haemolysis
- mannitol +
- facultative pathogens
- Species names:
-S. aureus susp. aureus: cattle, swine, horse, sheep, dog, poultry etc.
•MRSA: methicillin resistant S. aureus
-S. aureus subsp. anaerobius: sheep; Morel disease
-S. pseudointermedius: dog, cat; dermatitis, otitis externa
•S. intermedius: dog, horse, birds; mucous membranes
•saprophyte
Staphylococcus: Species: coagulase negative species 1. extracellular enzymes? 2. toxins? 3. haemolysis? 4. mannitol + or - ? 5. pathogens? 6. Species names?
- less extracellular enzymes
- toxin prod is not typical
- no haemolysis
- mannitol –
- generelly saprophytes, sometimes subclinical infection
•S. epidermidis: wound infection (horse, dog)
•S. haemolyticus: milk
•S. hyicus (part of strains is coagulase+): exudative epidermitis - Greasy pig disease
•S. gallinarum: dermatitis
•S. equorum: dermatitis
•S. felis: dermatitis
Micrococcus
- Habitat
- Morphology
- Biochemistry
- Pathogenicity
- Habitat: environment, mucous membrane, food, skin
- Morphology: coccus
- Biochemistry: glycose utilisation is aerobic or missing
- Pathogenicity: saprophyte
Streptococcus
- Habitat
- Morphology
- Staining
- Habitat: skin, mucous membrane, food, milk, digestive track
- Morphology: coccus, chain
• capsule: hyaluridic acid, polysaccharide (some species) - Staining: Gram positive
Streptococcus
4. Culture
- fastidious: blood agar, serum agar
- selective culture: crystal violet, thallium-SO4, esculin, blood (Edwards)
- haemolysis α −, β −haemolysis, no haemolysis
Streptococcus - Biochemistry
- Catalase/oxidase?
- Fermentative?
- Utilisation of glycosides?
- Extra cellular enzymes?
- Toxins?
- catalase -, oxidase -
- fermentatíve
- utilisation of glycosides: esculin, salicin
- extra cellular enzymes: fibrinolysin, hyaluronidase, nucleases, proteases
- toxins
Streptococcus:
6. Antigens
- complex
- Lancefield A-W
- other type specific antigens
- capsule antigens (S. suis, S. pneumoniae)
Streptococcus:
- Resistance
- Pathgenicity
- Grouping
- Resistance: good
- Pathgenicity:
• local suppuration,
• metritis, mastitis, arthritis,
• septicaemia,
• strangles,
• pneumonic diseases - Grouping: haemolysis, biochemical characteristics, antigens
Streptococcus:
10. Species
• S. pyogenes: capsule, toxin,
•human: scarlet fever, rheumatic fever, glomerulonephritis
• S. agalactiae, S. dysgalactiae, S. uberis: cow, ruminants -mastitis
•S. dysgalactiae subsp. equisimilis: lymphadenitis, abortion (horse)
•S. equi:
-subsp. equi: horse strangles
-subsp. zooepidemicus: suppuration, septicaemia, mastitis, abortion
• S. suis: septicaemia, arthritis, meningitis
• S. porcinus: lymphadenitis, abscesses
• S. canis: metritis, neonatal septicaemia
• S. bovis: septicaemia (pigeon)
• S. salivarius, S. sanguis, S. mutans: oral streptococci
• S. pneumoniae: calf, foal, human: pneumonia, meningitis
Enterococcus
- Habitat
- Morphology
- Culture
- Habitat: Gut
- Morphology: some isolates are motile
- Culture:
- Tolerate bile salt
- MacConkey agar
- 10-45 oC, pH 9,6, Lancefield D
- alpha-hemolysis
Enterococcus
- Species
- Pathogenecity
- Biochemistry
4.Species:
• E. faecalis
• E. faecium
• E. avium
• E. gallinarum
5. Pathogenecity: mainly saprophytes, sometimes endocarditis and abscesses
6. Biochemistry: Previosly in group D Streptococci since they posess the group D cell wall antigen
Lactococcus
- Habitat
- Culture
- Biochemistry
1.Habitat: gut flora (probiotic)
2.Culture: Lancefield N
• dairy products (starter cultures: Bulgarian milk, butter)
3.Biochemistry: fast lactose fermenters (homofermenters)
Lactococcus:
4. Species
- L. lactis subsp. lactis
- L. lactis subsp. cremoris
- L. plantarum: silage
Anaerobic cocci
1. Habitat
- mucous membranes
- saprophytes, sporadically inflammations
Anaerobic cocci
4. Species
- Peptococcus: metritis, arthritis, pneumonia
- Peptostreptococcus: metritis, arthritis, pneumonia
- Peptoniphilus: arthritis, septicaemia
- Ruminococcus: saprophytes
- Sarcina: saprophytes (rumen/large intestine of monogastrics)
Lactobacillus
- Habitat
- Morphology
- Staining
- Habitat: mucous membranes, gut, food, feed, plant
- Morphology: long, thin, sometimes curved rods
- Staining: Gram positive
Lactobacillus:
4. Culture
- microaerophilic
- optimal temperature 30-40 oC (2-53 oC)
- pH 5.5-6.2 (acidic)
Lactobacillus:
- Biochemistry
- Pathogencity
5. Biochemistry: • active fermentation, • lactate pH 4.0 • silage 6. Pathogencity: • saprophytes • mucous membranes (probiotic) • dairy industry
Lactobacillus:
7. Species
Saphrophytes • L. delbrücki subsp. bulgaricus • L. delbrücki subsp. lactis • L. acidophilus • L. salivarius • L. plantarum