We investigated the genetic basis of glycopeptide resistance in laboratory-derived strains of S. haemolyticus with emphasis on differences between vancomycin and teicoplanin. The genomes of two stable teicoplanin-resistant laboratory mutants selected on vancomycin or teicoplanin were sequenced and compared to parental S. haemolyticus strain W2/124. Only the two non-synonymous mutations, VraS Q289K and WalK V550L were identified. No other mutations or genome rearrangements were detected. Increased cell wall thickness, resistance to lysostaphin-induced lysis and adaptation of cell growth rates specifically to teicoplanin were phenotypes observed in a sequenced strain with the VraS Q289K mutation. Neither of the VraS Q289K and WalK V550L mutations was present in the genomes of 121S. haemolyticus clinical isolates. However, all but two of the teicoplanin resistant strains carried non-synonymous SNPs in vraSRTU and walKR-YycHIJ operons pointing to their importance for the glycopeptide resistance.

• Klíčová slova
• Mutation, Resistance, Staphylococcus haemolyticus, Teicoplanin, Vancomycin,
• MeSH
• antibakteriální látky farmakologie   MeSH
• bakteriální léková rezistence genetika   MeSH
• DNA bakterií genetika   MeSH
• fenotyp MeSH
• genom bakteriální genetika   MeSH
• histidinkinasa genetika   MeSH
• jednonukleotidový polymorfismus genetika   MeSH
• lidé MeSH
• rezistence na vankomycin genetika   MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza DNA MeSH
• stafylokokové infekce mikrobiologie   MeSH
• Staphylococcus haemolyticus účinky léků   genetika   izolace a purifikace   MeSH
• teikoplanin farmakologie   MeSH
• vankomycin farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Polsko MeSH
• Názvy látek
• antibakteriální látky MeSH
• DNA bakterií MeSH
• histidinkinasa MeSH
• teikoplanin MeSH
• vankomycin MeSH

Polymerase chain reaction (PCR) amplification of antibiotic resistance genes as well as staphylococcal cassette chromosome mec (SCCmec) typing and pulsed-field gel electrophoresis (PFGE) of SmaI macrorestriction fragments of genomic DNA were used to characterize 45 methicillin-resistant coagulase-negative staphylococci (MRCoNS) isolates responsible of bacteremia recovered in patients at the Bone Marrow Transplant Centre of Tunisia in 1998-2007. Among the 45 MRCoNS isolates, Staphylococcus epidermidis was the most prevalent species (75.6%) followed by Staphylococcus haemolyticus (22.2%) and Staphylococcus hominis (2.2%). Extended susceptibility profiles were generated for MRCoNS against 16 antimicrobial agents. Out of 45 mecA-positive strains, 43 (95.6%) were phenotypically methicillin-resistant and two (4.4%) were methicillin-susceptible. The msr(A) was the most prevalent gene (13 isolates; 48.1%) among erythromycin-resistant isolates. The erm(C) was found alone in seven (25.9%) or in combination with both erm(A) and erm(B) in two (7.4%) isolates. The aac(6')-Ie-aph(2″)-Ia was the most prevalent gene among aminoglycoside-resistant isolates, detected alone in 14 isolates (33.3%) isolates, in combination with ant(4')-Ia in 18 (42.8%) isolates, in combination with aph(3')-IIIa in four (9.5%) or with both ant(4')-Ia and aph(3')-IIIa in two (4.7%) isolates. The ant(4')-Ia was detected in three (7.1%) isolates and the aph(3')-IIIa in one (2.4%) isolate. Among tetracycline-resistant isolates, six (85.7%) strains harbored the tet(K) gene and one (14.3%) strain carried tet(K) and tet(M) genes. SCCmec types IV (31%) and III (24.5%), the most prevalent types detected, were found to be more resistant to non-β-lactam antibiotics. A wide diversity of isolates was observed by PFGE among MRCoNS.

• MeSH
• antibakteriální látky farmakologie   MeSH
• bakteriální geny MeSH
• bakteriální léková rezistence MeSH
• bakteriemie mikrobiologie   MeSH
• DNA bakterií genetika   metabolismus   MeSH
• hematologické nádory komplikace   MeSH
• koagulasa metabolismus   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• molekulární typizace MeSH
• polymerázová řetězová reakce metody   MeSH
• pulzní gelová elektroforéza MeSH
• restrikční endonukleasy typu II metabolismus   MeSH
• rezistence na methicilin * MeSH
• stafylokokové infekce mikrobiologie   MeSH
• Staphylococcus epidermidis klasifikace   účinky léků   genetika   izolace a purifikace   MeSH
• Staphylococcus haemolyticus klasifikace   účinky léků   genetika   izolace a purifikace   MeSH
• Staphylococcus hominis klasifikace   účinky léků   genetika   izolace a purifikace   MeSH
• techniky typizace bakterií MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Tunisko MeSH
• Názvy látek
• antibakteriální látky MeSH
• CCCGGG-specific type II deoxyribonucleases MeSH Prohlížeč
• DNA bakterií MeSH
• koagulasa MeSH
• restrikční endonukleasy typu II MeSH

We found a new variant of the streptogramin A resistance gene, vga(A)LC, in clinical isolates of Staphylococcus haemolyticus resistant to lincomycin and clindamycin but susceptible to erythromycin and in which no relevant lincosamide resistance gene was detected. The gene vga(A)LC, differing from the gene vga(A) at the protein level by seven amino acid substitutions, was present exclusively in S. haemolyticus strains resistant to both lincosamides and streptogramin A (LS(A) phenotype). Antibiotic resistance profiles of the ATP-binding cassette (ABC) proteins Vga(A)(LC) and Vga(A) in the antibiotic-susceptible host S. aureus RN4220 were compared. It was shown that Vga(A)LC conferred resistance to both lincosamides and streptogramin A, while Vga(A) conferred significant resistance to streptogramin A only. Detailed analysis of the seven amino acid substitutions, distinguishing the two related ABC proteins with different substrate specificities, identified the substrate-recognizing site: four clustered substitutions (L212S, G219V, A220T, and G226S) in the spacer between the two ATP-binding cassettes altered the substrate specificity and constituted the lincosamide-streptogramin A resistance phenotype. A transport experiment with radiolabeled lincomycin demonstrated that the mechanism of lincosamide resistance in S. haemolyticus was identical to that of the reported macrolide-streptogramin B resistance conferred by Msr(A).

• MeSH
• bakteriální geny MeSH
• bakteriální proteiny chemie   genetika   metabolismus   fyziologie   MeSH
• DNA bakterií genetika   izolace a purifikace   MeSH
• genetická variace * MeSH
• lidé MeSH
• linkosamidy MeSH
• makrolidy farmakologie   MeSH
• mikrobiální testy citlivosti MeSH
• mnohočetná bakteriální léková rezistence MeSH
• molekulární evoluce * MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza DNA MeSH
• Staphylococcus aureus účinky léků   genetika   MeSH
• Staphylococcus haemolyticus účinky léků   genetika   izolace a purifikace   MeSH
• streptogramin A farmakologie   MeSH
• substituce aminokyselin MeSH
• substrátová specifita MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• srovnávací studie MeSH
• Názvy látek
• bakteriální proteiny MeSH
• DNA bakterií MeSH
• linkosamidy MeSH
• makrolidy MeSH
• streptogramin A MeSH