| ID | • GPC • Catalase neg • Tend to grow in chains or pairs which then dissociate (important for early ID) • Classified in lab by haemolysis pattern on blood agar, and lancefield groupings | | --- | --- | | Site | • SSTI • LRTI • Abscess | | Alpha haemolytic | Alpha haemolytic: Hb part-digested (oxidised) to biliverdin —> green appearance.

What’s Optochin • Ethyl hydrocupreine hydrochloride • Interferes with ATPase in SPNE —> cell lysis (NB: Not 100% - some OPT-R strains exist) • Used to tell between S.pneumoniae and viridans Streptococci

Optochin-Sensitive; SPNE • Site: URT (never skin) • Causes LRTI, Abscess, Meningitis • Rx: Penicillin (beware Pen-Res in those with Hx foreign travel), Macrolide, Tetracyclines, Vanc

Optochin-Resistant: Viridans streps • Groups: My Mouthy Saliva’s Streptococci: Mitis, Mutans, Salivarus, Sanguinis • Cause 20% Strep IE; also meningitis, neutropenic sepsis, LRTI (in alcoholics & ppl with Lung Ca) • Also the Anginosis group:

• CIA: Constellatus, Intermedius, Anginosis
• Abscess forming features; Evade phagocytosis, contain adhesolysins/exotoxins, make friends with AnO —> polymicrobial infection
• Disseminate locally + in blood —> 10% Strep IE
• Rx: Beta-lactam +/- Gent (BLI if polymicrobial infection) | | Beta haemolytic | 2. Beta haemolytic: Streptolysin O causes full haemolysis  clearing around colony a. Lancefield Groupings: Carbohydrate groups on cell surface; antigenic; ID’d by mixing with sera. b. GAS: Pyogenes i. Site: skin ii. Mean. Lots of exotoxins. E.g. Strep TSS:

1. Superantigen
2. 24h mortality: 25%
3. Present in 10% cases iii. Causes SSTI, Joint, LRTI, septicaemia (20% no focus), Peripartum breast/genital/incisional sepsis iv. Rx:
4. BenPen +++
5. Toxin-neutralising Rx: a. Clindamicin (Linezolid?) – but 2% resistant b. IVIG (certain circumstances) c. GBS: Agalactiae i. Site: GIT ii. Causes meningitis/LRTI/Septicaemia in age extremes, and genital/placenta/choramnionitis in pregnant patients d. C/G: Dysgalactiae, Equisimilis, Zooepidemicus i. “mild GAS” ii. Site: Skin, URT iii. Causes: SSTI/joint, septicaemia | | Gamma (non) haemolytic | No haemolysis: Bovis group, also Lancefield group D (i.e. Enterococci) • Renamed + speciated by S.bovis biotype:

• I: Gallolyticus
• ii.1 Infantarius
• ii.2 Pasteurianus • Colonise GIT in 7% • Cause; Septicaemia (if colitis/adenoma/GB disease), IE (check for CoCa), joint/disc, meningitis • Ix: Echo, Colnooscopy, ?RUQ | | Rx | • Penicillin if you can.
• SPNE: Check for foreign travel to countries with Penicillin-resistant SPNE • Fluclox fine unless GBS (higher MIC breakpoints) • Cephalosporins (Ceftriaxone if CNS penetration needed); • Carbapenems • Macrolides • Tetracyclines (NB: no breakpoints for Viridans group, only BHS & S.pneumoniae) • Clindamicin (Esp. if toxin production) • Linezolid • Daptomycin (unless LRTI) • Cotrimoxazole • Higher-generation Quinolones: Levo, Moxi

Always get source control first | | Vaccine | None |

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Old prep note available here:

02_Streptococci Demystified.docx