High-Level Vancomycin-Resistant Staphylococcus aureus Isolates Associated with a Polymicrobial Biofilm
- 1 January 2007
- journal article
- research article
- Published by American Society for Microbiology in Antimicrobial Agents and Chemotherapy
- Vol. 51 (1), 231-238
- https://doi.org/10.1128/aac.00576-06
Abstract
Glycopeptides such as vancomycin are the treatment of choice for infections due to methicillin-resistant Staphylococcus aureus . This study describes the identification of high-level vancomycin-resistant S. aureus (VRSA) isolates in a polymicrobial biofilm within an indwelling nephrostomy tube in a patient in New York. S. aureus , Enterococcus faecalis , Enterococcus faecium , Micrococcus species, Morganella morganii , and Pseudomonas aeruginosa were isolated from the biofilm. For VRSA isolates, vancomycin MICs ranged from 32 to >128 μg/ml. VRSA isolates were also resistant to aminoglycosides, fluoroquinolones, macrolides, penicillin, and tetracycline but remained susceptible to chloramphenicol, linezolid, rifampin, and trimethoprim-sulfamethoxazole. The vanA gene was localized to a plasmid of ∼100 kb in VRSA and E. faecium isolates from the biofilm. Plasmid analysis revealed that the VRSA isolate acquired the 100-kb E. faecium plasmid, which was then maintained without integration into the MRSA plasmid. The tetracycline resistance genes tet (U) and tet (S), not previously detected in S. aureus isolates, were identified in the VRSA isolates. Additional resistance elements in the VRSA isolate included a multiresistance gene cluster, ermB-aadE-sat4-aphA-3 , msrA (macrolide efflux), and the bifunctional aminoglycoside resistance gene aac(6 ′ )-aph(2")-Ia . Multiple combinations of resistance genes among the various isolates of staphylococci and enterococci, including vanA , tet (S), and tet (U), illustrate the dynamic nature of gene acquisition and loss within and between bacterial species throughout the course of infection. The potential for interspecies transfer of antimicrobial resistance genes, including resistance to vancomycin, may be enhanced by the microenvironment of a biofilm.Keywords
This publication has 35 references indexed in Scilit:
- Methicillin-ResistantStaphylococcus aureusDisease in Three CommunitiesThe New England Journal of Medicine, 2005
- Biofilms as Complex Differentiated CommunitiesAnnual Review of Microbiology, 2002
- Biofilms: Survival Mechanisms of Clinically Relevant MicroorganismsClinical Microbiology Reviews, 2002
- Extracellular DNA Required for Bacterial Biofilm FormationScience, 2002
- Natural conjugative plasmids induce bacterial biofilm developmentNature, 2001
- Protocol for Detection of Biofilms on Needleless Connectors Attached to Central Venous CathetersJournal of Clinical Microbiology, 2001
- Seeking Vancomycin Resistant Staphylococcus aureus among Patients with Vancomycin-Resistant EnterococciClinical Infectious Diseases, 1999
- Conjugative transfer of tet(S) between strains of Enterococcus faecalis is associated with the exchange of large fragments of chromosomal DIMAMicrobiology, 1997
- Characterization of a new class of tetracycline-resistance gene tet(S) in Listeria monocytogenes BM4210Gene, 1993
- Co-transfer of vancomycin and other resistance genes from Enterococcus faecalis NCTC 12201 to Staphylococcus aureusFEMS Microbiology Letters, 1992