Characterisation of the Staphylococcussciuri group by Matrix-Assisted LaserDesorption/Ionisation Time-of-FlightMass Spectrometry
Staphylococcus aureus and coagulase-negative staphylococci
(CNS) are recognised as important nosocomial pathogens. Laboratory
identification and susceptibility testing remain important tools in the
epidemiology and control of staphylococcal infection. Multi-drug
resistance, particularly methicillin resistance is an escalating
problem. The mechanism of resistance is an escalating problem. The
mechanism of resistance among S. aureus (MRSA) and CNS is encoded by
the mec A gene, and has been found to be ubiquitous among the primitive
animal CNS- Staphylococcus sciuri. It has been hypothesised that S.
sciuri is a natural reservoir of methicillin resistance genes. Until
recently S. sciuri has seldom been recovered from clinical material and
rarely implicated in human infections. Over the past three at Ashford
Public Health Laboratory, 160 isolates of S. sciuri identified using
the API32 Staph (Biomerieux) have been recovered from clinical samples,
30% of which expressed methicillin resistance. Seventeen ATCC strains
of the S. sciuri group, comprising of S. sciuri subsp. scirui, S.
sciuri subsp. carnaticus, S. sciuri subsp. rodentium, S. lentus and S.
vitulinus were analysed using matrix-assisted laser
desportion/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS)
and a database created. The aim of this study is to identify and
compare clinical and non-clinical isolates using MALDI-TOF-MS. The
results will be used to assess any correlation between subspecies of S.
sciuri, and whether there is a link between expressed methicillin
resistance in clinical isolates and assumed exposure to antibiotic
pressure by comparing hospital acquired isolates with the community