Glycopeptide resistance in coagulase-negative staphylococci isolated in blood cultures from patients with hematological malignancies during three decades

Abstract

The aim of this study was to determine if there was a long-term increase in glycopeptide minimum inhibitory concentration (MIC) values, MIC creep, among bloodstream isolates of Staphylococcus epidermidis and S. haemolyticus isolated from patients with hematological malignancies. We conducted a retrospective single-center study where all positive blood cultures of S. epidermidis (n = 387) and S. haemolyticus (n = 19) isolated from patients with hematological malignancies during three decades, 1980 to 2009, were re-evaluated for the presence of reduced susceptibility to vancomycin and teicoplanin. Three different methods for the detection of reduced susceptibility to glycopeptides were used; standard Etest, macromethod Etest, and glycopeptide resistance detection (GRD) Etest. The median MIC value for vancomycin was 2 mg/L. MIC values for vancomycin and teicoplanin did not show any statistically significant increase during the study period. The presence of heterogeneously glycopeptide-intermediate staphylococci (hGIS) was analyzed among 405 coagulase-negative staphylococci (CoNS) isolates. hGIS were found in 31-45% of the CoNS isolates by the macromethod Etest and in 53-67% by the GRD Etest during the three decades. In conclusion, we did not observe any long-term glycopeptide MIC creep determined by the standard Etest, although a high and increasing proportion of heterogeneous vancomycin resistance was observed.

Efficacy of Daptomycin versus Vancomycin in an Experimental Model of Foreign-Body and Systemic Infection Caused by Biofilm Producers and Methicillin-Resistant Staphylococcus epidermidis

“…Foreign-body infections caused by MRSE strains are difficult to treat, mainly because of the presence of biofilm and bacterial tolerance to antibiotics (22). To date, vancomycin is the treatment of reference against MRSE infections, but several studies have pointed out its potential toxicity, limited bactericidal killing, and low capacity to cross biofilms as well as the inability to reach optimal pharmacodynamic parameters due to the increasing MIC of vancomycin against MRSE strains (1,14,19). On the basis of previous experimental studies, daptomycin currently plays a key role in the treatment of skin and soft-tissue infections caused by S. aureus (18a).…”

Activity of Tedizolid in Methicillin-Resistant Staphylococcus epidermidis Experimental Foreign Body-Associated Osteomyelitis

“…To date, vancomycin has been the treatment of choice for MRSE infections (8), but several studies have pointed out its potential toxicity, limited bactericidal action, and low level of activity against staphylococcal biofilms as well as its inability to reach optimal pharmacodynamic parameters due to the relatively high vancomycin MIC values of MRSE (9,10). Rifampin has shown activity in biofilm-related infections (11,12).…”

tuf Gene Sequence Analysis Has Greater Discriminatory Power than 16S rRNA Sequence Analysis in Identification of Clinical Isolates of Coagulase-Negative Staphylococci

“…However, the accuracy of these tests can be compromised because of the variable expression of phenotypic characteristics and the limited nature of the databases; these limitations can result in ambiguous findings and the inability to identify uncommon isolates (4,15,17). In addition, identification of CNS to the species level may change the diagnosis and therapeutic plans, since uncommon isolates are being considered as causative agents, and unusual antibacterial resistance patterns appear (1,13). Therefore, genotypic methods of identifying CNS species are emerging as diagnostic tools for CNS infections.…”