STAPHYLOCOCCACEAE STREPTOCOCCACEAE Lab 10 A L Noor ameer

STAPHYLOCOCCACEAE & STREPTOCOCCACEAE Lab. 10 A. L. Noor ameer

GENUS a- Staphylococcus aureus: Pathogenic & commensally found in nose (nares) b- Staphylococcus epidermidis: Opportunistic pathogens found in nares & skin c- Staphylococcus saprophyticus: Opportunistic pathogens Cause UTI in female & found skin.

GENERAL CHARACTERISTICS OF STAPHYLOCOCCI: Gram positive cocci, grape-like, non motile, non spore forming, mostly non capsulated, aerobic & facultative anaerobic, catalase positive, resist high concentration of of Nacl (10% Nacl), moderately resist to heat (50 - 60 Co for 1 -1. 5 hr).

ISOLATION & PATHOGENICITY - Staphylococcus aureus: are responsible for the : Skin infection, abscess formation, boils, acne and impetigo - Staphylococcus epidermidis: may be the etiological agent for skin lesion and endocarditis - Staphylococcus saprophyticus: has been implicated in some urinary tract infection (UTI)

CLINICAL SAMPLES 1 - Pus: in case of (abscesses, burn swab, acne swab) 2 - Sputum: in case of (respiratory tract infection) 3 - Stool: in case of (enteritis) food poisoning 4 - Blood: in case of (bacteremia)

TOXINS & ENZYMES: Catalase, Coagulase, Nuclease (DNase), Clumping factor, Leucocidin, Hyaluronidase, Enterotoxin, Haemolysin, Proteinase, Lipase, β -lactamase

LABORATORY DIAGNOSTIC TESTS: 1 - Gram stain: gram positive cocci, clusters shape 2 - Blood agar (Haemolysin) 3 - Brain heart infusion agar (BHI) for pigment 4 - Staph 110 (tolerance to 7. 5% Nacl) selective media for Staphylococcus

5 - Mannitol salt agar (selective & differential), selective for Staphylococcus because it contains 7. 5% Nacl, differential for Staphylococcus aureus because it ferment Mannitol 6 - Coagulase & Catalase tests

STREPTOCOCCACEAE Genus: a- Streptococcus pyogenes b- Streptococcus agalactiae c- Streptococcus pneumoniae d- Streptococcus faecalis

GENERAL CHARACTERISTICS OF STREPTOCOCCI Gram positive cocci that appear in chains, most of them are facultative anaerobic, catalase negative, pin point colonies on solid media, nutritionally fastidious, growth temp. between 1545 CO, they are also grow in high concentration of Nacl (6. 5%) & in bile salt broth

CLASSIFICATION OF STREPTOCOCCUS: 1 - Based on type of haemolysis: a- α - haemolytic : Streptococcus pneumoniae & Streptococcus viridans b- β – haemolytic : Streptococcus pyogenes & Streptococcus agalactiae. c- γ- hemolytic : Enterococcus faecalis. 2 - Serological classification Depends on the presence of O Ag, which classified into: - Group A: Streptococcus pyogenes, Group B: Streptococcus agalactiae Group C: Streptococcus equi , Group D: Enterococcus faecalis 3 - Sensitivity to antibiotics: mainly bacitracin & optochin, differ from species to another & they used in identification of Streptococci.

LABORATORY DIAGNOSTIC TESTS: Samples: sputum, laryngeal swabs, blood, transtracheal aspiration. 1 - Gram stain: G +ve. cocci 2 - Bile solubility 3 - Blood agar: for the type of haemolysin 4 - Streptokinase test: indicate the lysis of plasma clot. 5 - Bacitracin & optochin

6 - Quelling reaction: this performed for capsulated Streptococcus pneumoniae 7 - Salt tolerance: group D can grow in 6. 5% Nacl & can grow in temp. 10 -45 Co. 8 - CAMP reaction: is used to identify Streptococcus agalactiae (group B) (CAMP positive)