We determined the activities of new antibiotics telithromycin (ketolide) and quinupristin/dalfopristin (streptogramins) against 88 macrolide and/or lincosamide resistant coagulase-negative staphylococci (CoNS) isolates with defined resistance gene status. Telithromycin susceptibility was determined only in erythromycin-sensitive isolates (15) indicating the same mechanisms of resistance. In contrast, all erythromycin-resistant isolates (73) were either constitutively resistant to telithromycin (13 isolates with constitutive erm genes) or demonstrated telithromycin D-shaped zone (60 isolates with inducible msr(A) and/or erm). However, the level of inducible resistance conferred by msr(A) (35 isolates) was borderline even after induction by erythromycin. No quinupristin/dalfopristin resistant isolate was observed if tested by disk-diffusion method (DDM) but 18 isolates were intermediate (MIC = 1-3 mg/L) and two isolates resistant (MIC = 8 mg/L) if tested by E-test. All these isolates were resistant to streptogramin A and harbored vga(A) gene (1 isolate) or vga(A)LC gene (19 isolates). MICs for quinupristin/dalfopristin were higher for isolates with combination of streptogramin A resistance and constitutive MLSB resistance (MIC = 3-8 mg/L in 4 isolates) than for streptogramin A-resistant isolates susceptible to streptogramin B (MIC = 0.5-2 mg/L in 16 isolates). In addition to S. haemolyticus, vga(A)LC was newly identified in S. epidermidis and S. warnerii indicating its widespread occurrence in CoNS. Misidentification of low-level resistant isolates by DDM may contribute to dissemination of streptogramin A resistance.

Institute of Microbiology Academy of Sciences of the Czech Republic 142 20 Prague Czechia

See more in PubMed

J Antimicrob Chemother. 2005 Feb;55(2):260-4 PubMed

J Antimicrob Chemother. 2002 Mar;49(3):580-2 PubMed

J Antimicrob Chemother. 2002 Jul;50(1):145-8 PubMed

J Clin Microbiol. 2006 Dec;44(12):4444-54 PubMed

Int J Antimicrob Agents. 2003 Jul;22(1):87-8 PubMed

J Antimicrob Chemother. 2005 May;55(5):811-2 PubMed

Antimicrob Agents Chemother. 2005 Jul;49(7):3059-61 PubMed

J Antimicrob Chemother. 1997 Jul;40(1):85-90 PubMed

J Clin Microbiol. 2003 Feb;41(2):586-91 PubMed

FEMS Microbiol Lett. 1998 Oct 15;167(2):221-7 PubMed

J Antimicrob Chemother. 2000 Dec;46(6):941-9 PubMed

Mol Microbiol. 1990 Jul;4(7):1207-14 PubMed

Antimicrob Agents Chemother. 2005 Aug;49(8):3586-9 PubMed

Antimicrob Agents Chemother. 1985 Sep;28(3):421-4 PubMed

Antimicrob Agents Chemother. 1999 Nov;43(11):2720-5 PubMed

Antimicrob Agents Chemother. 2006 Jan;50(1):237-42 PubMed

Microb Drug Resist. 2002 Fall;8(3):171-7 PubMed

Gene. 1996 Dec 12;183(1-2):143-8 PubMed

Antimicrob Agents Chemother. 2000 May;44(5):1168-73 PubMed

Antimicrob Agents Chemother. 1996 Apr;40(4):992-8 PubMed

FEMS Microbiol Lett. 1999 Dec 1;181(1):91-100 PubMed

Antimicrob Agents Chemother. 1999 May;43(5):1062-6 PubMed

Antimicrob Agents Chemother. 1996 Nov;40(11):2523-8 PubMed

Antimicrob Agents Chemother. 2006 Dec;50(12):4070-6 PubMed

J Antimicrob Chemother. 2006 May;57(5):966-9 PubMed

J Bacteriol. 1969 May;98(2):447-52 PubMed

Clin Microbiol Infect. 2006 Sep;12(9):844-52 PubMed

ClpP-independent function of ClpX interferes with telithromycin resistance conferred by Msr(A) in Staphylococcus aureus

Mutasynthesis of lincomycin derivatives with activity against drug-resistant staphylococci

Detection of methicillin and mupirocin resistance in staphylococcal hospital isolates with a touchdown multiplex polymerase chain reaction

Multiplex PCR detection of the antibiotic resistance genes in Staphylococcus aureus strains isolated from auricular infections