Tolerance to the Glycopeptides Vancomycin and Teicoplanin in Coagulase-Negative Staphylococci

Abstract

Tolerance to vancomycin and teicoplanin in 90 clinical isolates of coagulase-negative staphylococci (CoNS) was investigated by time-kill curve methodology. Only six strains, belonging to the Staphylococcus lugdunensis species, exhibited tolerance. The seven other S. lugdunensis strains tested displayed weak susceptibility to the bactericidal activity of glycopeptides compared to the other CoNS. These phenomena are of concern, since S. lugdunensis is recognized as one of the most pathogenic CoNS.Coagulase-negative staphylococci (CoNS) are involved in infections that require bactericidal treatment, such as indwelling foreign body-related infections, endocarditis, and meningitis (4, 10). As CoNS become more resistant to beta-lactams (2), glycopeptides are often considered to be antibiotics of last resort (12). Some investigators, however, have reported glycopeptide tolerance for sporadic CoNS (16,23). Antibiotic tolerance describes a particular "type of resistance" in bacteria capable of surviving, but not growing, in the presence of a normally lethal dose of a given bactericidal antibiotic (20, 21). As early screenings for glycopeptide tolerance in CoNS have been performed by the controversial minimal bactericidal concentration (MBC)/MIC determinations (1,14,19,21), the present study was designed to examine vancomycin and teicoplanin tolerance in a collection of clinically significant CoNS by using the killing curve method, which is considered to be the most reliable method according to the Clinical and Laboratory Standards Institute (CLSI) (formerly NCCLS) (14).An initial set of 79 clinically significant isolates of CoNS from 79 individual patients attending the Rouen University Hospital between January 1999 and April 2001 was studied. Strains were identified to the species level with the ID32Staph system (bioMérieux, Marcy l'Etoile, France) and by a gap gene PCR-restriction fragment length polymorphism assay (24). This set reflected the current epidemiology of CoNS (11), with Staphylococcus epidermidis as a very dominant species (n ϭ 66; 84% of the isolates) and with some less frequently encountered species, i.e., S. hominis (n ϭ 4), S. capitis (n ϭ 3), S. lugdunensis

Teicoplanin non-susceptible coagulase-negative staphylococci in a large Australian healthcare network: Implications for treatment with vancomycin

“…8,11,12 Other species which have been reported to be glycopeptide non-susceptible include S. lugdunensis, S. capitis and S. simulans. 2,4,6,13 However, none of these species were identified as Teico-NS in the current study. CoNS from patients in ICU were more likely to be Teico-NS.…”

“…CoNS are now the second most common cause of prosthetic valve endocarditis after S. aureus and one of the most frequent pathogens isolated from deep-seated prosthetic implant infections. 4,5 CoNS have also become one of the most common causes of bacteraemia in immunosuppressed patients. 2 Treatment of CoNS infections can be challenging owing to the frequent presence of foreign materials and increasing antimicrobial resistance.…”

Multilocus Sequence Typing Analysis of Staphylococcus lugdunensis Implies a Clonal Population Structure

“…Penicillinase production is observed for less than 50% of isolates (14), and methicillin resistance is still rare (30,38). However, a particular feature of S. lugdunensis is vancomycin and/or teicoplanin tolerance (4,14). We found, by analyzing seven coagulase-negative staphylococcal species, that this glycopeptide tolerance phenomenon was restricted to S. lugdunensis.…”

“…We found, by analyzing seven coagulase-negative staphylococcal species, that this glycopeptide tolerance phenomenon was restricted to S. lugdunensis. Indeed, all the S. lugdunensis isolates investigated displayed strict glycopeptide tolerance or at least decreased and slower susceptibility to glycopeptide bactericidal activity (4).…”

Genotypic Diversity of Coagulase-Negative Staphylococci Causing Endocarditis: a Global Perspective

“…Although more than 40 species make up this heterogeneous group of microorganisms, identification of CNS to the species level often is not performed because of laboratory uncertainty about its clinical relevance or the absence of reliable identification systems (10). There is, however, growing evidence that identification of CNS to the species level may alter diagnostic and therapeutic clinical decision making where specific species have unique virulence factors (e.g., Staphylococcus lugdunensis) (2) or unusual antibacterial resistance patterns (e.g., glycopeptide resistance with S. epidermidis and S. haemolyticus) (4)(5)(6). In recent years, partial 16S rRNA gene sequencing has emerged as an accurate and reliable method to identify CNS, but this molecular target is limited by having less than 1% sequence divergence among some CNS species.…”