Pathogenic and opportunistic cocci. Classification, biological properties. Staphylococci, streptococci, gonococci and meningococci.

Staphylococcus Classification Family – Micrococcaceae Genus – Staphylococcus Species: 1.S. aureus 2.S. epidermidis 3.S. saprophyticus

Staphylococci in the pure culture and in the pus smears

Culture They grow readily on ordinary culture media The optimal temperature being 37 0 C and pH 7,4-7,6 They are aerobes and facultative anaerobes Culture media: nutrient agar, blood agar, salt media

Differentiation of the S.aureus from opportunists Hemolysis appearance on the blood agar DNAase activity (on the top)

Differentiation of the staphylococci Coagulase activity (test is positive for S.aureus) Novobiocin disk test to differentiate S.saprophyticus (left) and S.epidermidis (right)

Pathogenesis Staphylococcal diseases may be classified as 1.Cutaneous infections 2.Deep infections 3.Food poisoning 4.Nosocomial infections (hospital infections) 5.Skin exfoliative disease (staphylococcal scalded skin syndrome) 6.Toxic shock syndrome

Laboratory diagnosis Direct microscopy Culture.

The characteristics help to distinguish the pathogenic strains from non-pathogenic strains Beta type of haemolysis on blood agar Production of a golden yellow pigment Coagulase production Mannitol fermentation Gelatin liquefaction Phosphatase production Production of enzyme deoxyribonuclease Tellurite reduction

Prophylaxis General prophylaxis.

Staphylococcus aureus

Streptococcus Classifications: A. Due to type of hemolysis B. Lancefield´s classification (serological) C. Due to phylogenetic relationship

Different types of hemolysis Α -Hemolysis Β-Hemolysis Γ-Hemolysis

S.pyogenes (smears from the agar culture(on the left) and sugar broth (on the right)

S.pneumoniae (smears from the pure culture and from the sputum)

Culture aerobes and facultative anaerobes media containing blood, serum or sugars.

Laboratory diagnosis Suppurative infections : microscopy and pure culture isolation Non-suppurative sequelae: serology

Streptococcus pyogenes

Neisseria Classification Family - Neisseriaceae Genus – Neisseria Species: 1.N. meningitidis 2.N. gonorrhoeae

N. meningitidis in the smears from the pure culture and clinical sample

Culture They are strict aerobes. The optimum temperature and pH for growth are C and 7,4-7,6 respectively. Growth occurs in media enriched with blood, serum or ascitic fluid.

Antigenic classification N. meningitidis has been divided into 13 serogroups

Laboratory diagnosis Direct microscopy Antigen detection Culture. Serology Polymerase chain reaction.

Prophylaxis Chemoprophylaxis Immunoprophylaxis.

Neisseria meningitidis

N. gonorrhoeae

Laboratory diagnosis Direct microscopy. Culture. Serology