JAC Advance Access originally published online on July 1, 2005
Journal of Antimicrobial Chemotherapy 2005 56(2):287-291; doi:10.1093/jac/dki227
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Genotypic versus phenotypic characterization, with respect to susceptibility and identification, of 17 clinical isolates of Staphylococcus lugdunensis
1 Microbiology Department, Hospital Gómez-Ulla, Gta. del Ejército s/n, 28007 Madrid, Spain; 2 Microbiology Department, School of Medicine, Universidad Complutense, Avda. Complutense s/n, 28040 Madrid, Spain
Received 4 February 2005; returned 24 May 2005; revised 30 May 2005; accepted 2 June 2005
* Corresponding author. Tel: +34-91-3941508; Fax: +34-91-3941511; E-mail: jprieto{at}med.ucm.es
Objectives: To compare different methods for the identification and determination of susceptibility to penicillin and methicillin of Staphylococcus lugdunensis.
Methods: Seventeen clinical isolates of S. lugdunensis (identified by PCR amplification and sequencing of the rpoB gene) were studied using the ATB32-Staph, Crystal, Vitek 2 and Wider commercial systems. The clumping factor test and the tube coagulase test were also performed. ß-Lactamase production was studied by chromogenic methods. Methicillin resistance was phenotypically studied by the MRSA slide latex agglutination test, growth in MRSA agar, and the Vitek 2 and Wider systems (based on oxacillin MIC), and genotypically studied by detection of the mecA gene by PCR.
Results: The clumping factor test was negative in 35.3% of strains. All isolates were correctly identified to species level by the ATB32-Staph system. Species misidentification rates were 5.9%, 23.5% and 29.4% with the Crystal, the Vitek 2 and the Wider systems, respectively, mostly as Staphylococcus haemolyticus. ß-Lactamase was present in 11.8% of strains. Whereas 76.5% and 47.1% of strains exhibited oxacillin resistance (MIC range 0.5–2 mg/L) by the Vitek 2 system and the Wider system, respectively, none of the strains was positive in the MRSA slide latex agglutination test or grew in MRSA agar. All strains lacked the mecA gene.
Conclusions: The clumping factor test and some commercial systems may misidentify S. lugdunensis. Oxacillin resistance detected by commercial systems is not indicative of the presence of the mecA gene. These facts, together with ß-lactamase production, may preclude adequate treatment of infections by this virulent coagulase-negative Staphylococcus.
Keywords: S. lugdunensis , methicillin resistance , ß-lactamases , mecA gene , clumping factor
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  T. Y. Tan, S. Y. Ng, and J. He Microbiological Characteristics, Presumptive Identification, and Antibiotic Susceptibilities of Staphylococcus lugdunensis J. Clin. Microbiol., July 1, 2008; 46(7): 2393 - 2395. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. L. Frank, J. L. del Pozo, and R. Patel From Clinical Microbiology to Infection Pathogenesis: How Daring To Be Different Works for Staphylococcus lugdunensis Clin. Microbiol. Rev., January 1, 2008; 21(1): 111 - 133. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. L. Frank, E. J. Reichert, K. E. Piper, and R. Patel In Vitro Effects of Antimicrobial Agents on Planktonic and Biofilm Forms of Staphylococcus lugdunensis Clinical Isolates Antimicrob. Agents Chemother., March 1, 2007; 51(3): 888 - 895. [Abstract] [Full Text] [PDF]
|
|