Teicoplanin susceptibility

Majcherczyk PA, McKenna T, Moreillon P, Vaudaux P. The discriminatory power of MALDI-TOF mass spectrometry to differentiate between isogenic teicoplanin-susceptible and teico-planin-resistant strains of methicillin-resistant Staphylococcus aureus. FEMS Microbiol Lett. 2006 255 233-9. 

Other specific discovery assays have been used such as differential inhibition of a vancomycin resistant S. aureus strain and its susceptible parent, and an assay based on antagonism of the antibacterial activity by N,A/-diacetyl-L-Lys-D-Ala-D-Ala [24570-39-6] a tripeptide analogue of the dalbaheptides receptor. AppHcation of this latter test to 1936 cultures (90) led to the isolation of 42 dalbaheptides, six of which, including kibdelin (Table 3), parvodicin (Table 3), and actinoidin A2 (68) were novel. A colorimetric assay based on competition between horseradish peroxidase bound teicoplanin and the... 

VanB-type has been less well-characterized but essentially operates in a similar manner to VanA. Both inducible and constitutive forms of resistance have been described, but the reasons for susceptibility to teicoplanin are unclear. 

Glycopeptide resistance in a cluster of three clinical isolates of vancomycin-resistant Enterococcus faecium was due to vanD, which was located on the chromosome and was not transferable to other enterococci These isolates were indistinguishable but differed from the strain in which vanD-mediated resistance has been reported previously (102). A type of acquired glycopeptide resistance, named vanE, has been characterized in E. faecalis BM 4405. It results in low-level resistance of vancomycin but susceptibility to teico-planin (103). Defects in penicillin-binding protein 4 result in a distorted peptidoglycan composition of the cell of vancomycin-resistant and teicoplanin-resistant laboratory mutants of S. aureus and are suggested to be part of the mechanism of glycopeptide resistance in these microbes (104). 

Antibiotic resistance behaviour of 308 enterococci isolated from Bryndza cheese is shown in Fig. 5. All enterococcal isolates from Bryndza cheese were susceptible to ampicillin, streptomycin, gentamicin, vancomycin, and teicoplanin. For these same isolates, resistance rates to rifampicin, erythromycin, ciprofloxacin, and... 

Enterococcal resistance to vancomycin is the result of alteration of the D-Ala-D-Ala target to D-Ala-D-lactate or D-Ala-D-Ser, which bind vancomycin poorly. Several mutations are required for this target alteration and distinct phenotypes have been described. The Van A phenotype confers inducible resistance to teicoplanin and vancomycin in E. faecium and E. faecalis. The Van B phenotype, which tends to be a lower level of resistance, also has been identified in E. faecium and E. faecalis. The trait is inducible by vancomycin but not teicoplanin, and consequently, many strains remain susceptible to teicoplanin. 

Resistance can emerge in susceptible staphylococci during therapy. The Van A phenotype of vancomycin resistance also confers resistance to teicoplanin by altering the cell-wall target so that the glycopeptide does not bind. Strains of enterococci with Van B resistance often remain susceptible to teicoplanin. 

Daum RS. Gupta S, Sabbagh R. Milewski WM. Characteritation of Staphylococcus aureus isolates with decreased susceptibility to vancomycin and teicoplanin Isolation and punhca tion of a constitutiveiy produced protein associated with decreased susceptibility. J Infect Dis 1992 166 1066-1072. 

Empiric therapy should be tailored to each institution s resistance profile, but usually will include vancomycin (or cefazolin if low prevalence of MRSA) plus another antibiotic with Gram-negative coverage (e.g., third-generation cephalosporin, carbapenem, or p-lactam/p-lactamase inhibitor). If methicillin-susceptible S. aureus is found as the causative pathogen, then cefazolin or flucloxa-cillin/oxacillin should be the treatment of choice. In general, we prefer antibiotics that need to be administered after dialysis only. The most commonly utilized postdialysis antibiotic regimens include vancomycin, teicoplanin, cefazolin. 

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