- vancomycin is one of the antibiotics with intracellular bactericidal activity and therefore should cover small colony variants of staphylococci and MRSA;
- vancomycin is a glycopeptide and may have intrinsic ability to bind to glycocalyx and penetrates glycocalices very rapidly;
- note that with a glycocalyx formation, the MIC value (and the trough levels) will have to be higher;
- once incorporated in biofilm Vancomycin shows a strain dependent bactericidal biofilm activity between 8 times and 128 times the MIC of planktonic bacteria;
- shows superior bactericidal activity against biofilm embedded staphylococci and MRSA compared with most other antibiotics;
- references:
- Impact of biofilm on the in vitro activity of vancomycin alone and in combination with tigecycline and rifampicin vs Staphylococcus aureus.
- Comparison of biofilm-associated cell survival following in vitro exposure of meticillin-resistant Staphylococcus aureus biofilms to the antibiotics clindamycin, daptomycin, linezolid, tigecycline and vancomycin.
- In situ measurement of linezolid and vancomycin concentrations in intravascular catheter-associated biofilm
- staph aureus
- Direct demonstration of viable Staphylococcus aureus biofilms in an infected total joint arthroplasty. A case report.
- staph epi:
- its high recurrence rate may be related to its propensity to form a biofilm layer (extra-cellular glycocalyx) which coats the bacteria, which protects by engulfment by neutrophils;
- slime layer may make antibiotic penetration and bacteria eradication more difficult;
- references:
- Adherence of Staphylococcus epidermidis to biomaterials is augmented by PIA.
- Occurrence of ica genes for slime synthesis in a collection of Staphylococcus epidermidis strains from orthopedic prosthesis infections.
- Identification and preliminary characterization of cell-wall-anchored proteins of Staphylococcus epidermidis.
- small colony variants:
- may not provoke increase in CRP;
- do not produce virulence factors
- culture:
- hemin and menadion need to be added to grow the small-colony variants (or will have false negatives);
- may be listed incorrectly as coagulase-negative staph;
- small colony MIC for aminoglycoside antibiotics can be 16 times higher than for large colony types
- slow growth and slow cell division reduces antibiotic effectiveness (antibiotics that act on cell walls);
- small colony variants have the ability to survive in soft tissue cells;
- antibiotics that do not affect the cell wall may be effective:
- tetracycline (hydrophilic antibiotic)
- rifampin (hydrophobic antibiotic) + cipro
- pseudomonas - the only gram negative that produces a biofilm layer.
- labs:
- C-reactive protein
- produced in the liver by cytokines - IL-6
- staph small-colony variants do not produce virulence factors nor a-toxin which would stimulate increase in C-reactive protein
- references:
- Application of a rat osteomyelitis model to compare in vivo and in vitro the antibiotic efficacy against bacteria with high capacity to form biofilms.
- Improved aero-anaerobe recovery from infected prosthetic joint samples taken from 72 patients and collected intraop in Rosenow's broth.
- Biofilm Theory Can Guide the Treatment of Device-Related Orthopaedic Infections.
- Is Aseptic Loosening Truly Aseptic?
- The Coventry Award. The value of preoperative aspiration before total knee revision.
- Is "aseptic" loosening of the prosthetic cup after total hip replacement due to nonculturable bacterial pathogens in patients with low-grade infection?
- Sonication of removed hip and knee prostheses for diagnosis of infection.
- Prior Use of Antimicrobial Therapy is a Risk Factor for Culture-negative Prosthetic Joint Infection
- Small-Colony Variants Need Big-Time Busting
- Metal-on-metal bearings in total hip arthroplasties: Influence of cobalt and chromium ions on bacterial growth and biofilm formation.
- The role of small-colony variants in failure to diagnose and treat biofilm infections in orthopedics.
- Bacterial Adhesion: Seen Any Good Biofilms Lately?