[Evaluation of IDI-MRDA assay on a collection of community-acquired methicillin-resistant Staphylococcus aureus isolates and on carriage specimens].
The efficacy of infection control measures against MRSA is linked to the rapid detection of MRSA. With the conventional diagnosis by culture the response delays vary from 48 to 72 hours. In contrast molecular techniques give results within hours.


OBJECTIVE
The objective of the present study is to perform the IDI-MRSA PCR test (BD Diagnostic GeneOhm) on a collection of characterized community-acquired MRSA (CA-MRSA) isolates and on carriage specimens. COLLECTION OF ISOLATES: Fifty-two isolates of CA-MRSA previously characterised by their toxinotype and SCCmec type cassette were analysed. All of them were identified as MRSA by the IDI-MRSA test.


METHODS
Seventy screening specimens from 35 different patients were tested in comparison with the culture on specific media (MRSA ID, BioMérieux). Among those 70 specimens, 24 were from nose, 25 from cutaneous sites (axillar; groin) and 21 from other sites. Sensitivity and specificity were 86.4 and 91.3% respectively; positive and negative predictive values were 93.3 and 82.6% respectively.


RESULTS
Three of four false-positive results came from specimens collected during a decolonisation treatment. Without taking account those specimens, specificity and positive predictive reach 97.9 and 95% respectively. This study shows that IDI-MRSA is an interesting additional test for the diagnosis of MRSA carriage.
Liassine
N
N
Unilabs Genève, 53, avenue Blanc, 1211 Genève 2, Suisse. nliassine@unilabs.ch
Decosterd
F
F
Etienne
J
J
D003470:Culture Media; D005189:False Positive Reactions; D006801:Humans; D016106:Methicillin Resistance / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods*; D011237:Predictive Value of Tests; D013203:Staphylococcal Infections / Q000145:classification / Q000175:diagnosis / Q000635:transmission*; D013211:Staphylococcus aureus / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification
D003470:Culture Media