| ID | • GPC – pairs, short chains • Catalase neg • Facultative Anaerobe • Non-haemolytic • Lancefield group D • Historically classified alongside streptococci ◦ now in a separate Family; Enterococcaceae (enterococci are the only genus that infect humans) ◦ 500m years old!
• 90-95%: E.faecalis • 5%: E.faecium • <1%: E. casseliflavus, E. gallinarum, and E. raffinosus | | --- | --- | | Site | • UGI tract • Biliary tract (Alkaline-resistant) | | Clinical syndromes | NB: Opportunistically pathogenic, fairly indolent. • UTI • BSI • Endocarditis • SBP • Meningitis (rare; complication of neuro device infection) | | Risk Factors | • | | Pathogenic mechanisms | • | | Lab ID | | | Rx | Oral therapy: • Amoxicillin: faecaliS = Sensitive, E.faeciuM = Must use another antibiotic! • Linezolid • Nitrofurantoin for UTIs
IV: • Amoxicillin if possible (EFLIS) • Vancomycin (Binds D-Ala-D-Ala in peptidoglycan precursor molecules —> prevents cross-linkage) • Daptomycin • Tigecycline • Quinupristin/dalfopristin (EFIUM) – Synercid; streptogramin derivatives (protein synthesis inhibitors) | | AMR | Intrinsically resistant: • Cephalosporins • Carbapenems • Aminoglycosides • Quinolones • Amoxicillin: faecaliS = Sensitive, E.faeciuM = Must use another antibiotic!
VRE Genes: Encodes for peptidoglycan precursors with a different end-terminal, which would be crosslinked by PBPs:
• Van-A: 1000x less binding affinity ◦ All glycopeptides are useless ◦ “A for aureus”; found in VRSA • Van-B: 1000x less binding affinity; Use your Backup glycopeptide: Teicoplanin (doesn’t induce VanB expression, whereas Vanc does) • Van-C: 7x less binding affinity
VanA/B move around via transposons; VanC is species-specific | | Vaccine | • None |
Summary of Glycopeptide resistance genes in gram-positive organisms.
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