Evaluation of the real-time PCR assay for the detection of fluoroquinolone-resistant Staphylococcus aureus using a variety of bacteria

Bacterial species (strain number)Fluorescent signal with the indicated test and probea
PCR no. 1PCR no. 2
Abiotrophia defectiva (ATCC 49176)
Bacillus cereus (ATCC 13472)
Bacillus mycoides (ATCC 10206)
Enterococcus faecalis (ATCC 29212)
Enterococcus faecalis (ATCC 19433)
Enterococcus flavescens (ATCC 49996)
Granulicatella adiacens (ATCC 49175)
Lactococcus lactis (ATCC 11454)
Listeria innocua (ATCC 33090)
Listeria monocytogenes (ATCC 15313)
Staphylococcus auricularis (ATCC 33753)
Staphylococcus capitis subsp. urealyticus (ATCC 49326)
Staphylococcus carnosus (ATCC 51365)
Staphylococcus chromogenes (ATCC 43764)
Staphylococcus epidermidis (ATCC 35983)
Staphylococcus epidermidis (ATCC 35984)
Staphylococcus gallinarum (ATCC 35539)
Staphylococcus haemolyticus (ATCC 29970)
Staphylococcus haemolyticus (LSPQ 2514)
Staphylococcus hominis subsp. hominis (ATCC 27844)
Staphylococcus lentus (ATCC 29070)
Staphylococcus lugdunensis (ATCC 43809)
Staphylococcus saccharolyticus (ATCC 14953)
Staphylococcus saprophyticus (ATCC 15305)
Staphylococcus saprophyticus (ATCC 35552)
Staphylococcus saprophyticus (ATCC 43867)
Staphylococcus simulans (ATCC 27848)
Staphylococcus warneri (ATCC 27836)
Staphylococcus xylosus (ATCC 29971)
Streptococcus agalactiae (ATCC 12400)
Streptococcus pneumoniae (ATCC 49619)
S. aureus (ATCC 25923)b++++
S. aureus (ATCC 29213)b++++
S. aureus (CCRI-2024)b+++
S. aureus (9191)b+++
S. aureus (9299)b+++
S. aureus (9015)b+++
S. aureus (9283)b+++
S. aureus (CCRI-12876)b++
  • a All PCR tests were performed using 0.1 ng of purified genomic DNA.

  • b These strains were chosen to represent different mutations at codons 80 and 84 of grlA. The quinolone resistance-determining regions of grlA from these strains were sequenced in this study. S. aureus strains ATCC 25923 and ATCC 29213 have no mutation at codons 80 and 84; strains CCRI-2024, 9191, and 9299 have a Ser-80-to-Phe (TCC→TTC) mutation; strain 9015 has a Glu-84-to-Gly (GAA→GGA) mutation; strain 9283 has a Glu-84-to-Lys (GAA→AAA) mutation; and strain CCRI-12876 has both Ser-80-to-Tyr (TCC→TAC) and Glu-84 to Gly (GAA→GGA) mutations.