CULTURES FOR METHICILLIN - RESISTANT STAPHYLOCOCCUS AUREUS FROM 29 COLONIZED PATIENTS Site Samples Nose

Ceftazidime proved an excellent selective antibiotic for this MRSA in subcultures from the enrichment medium; interference from contaminating flora was noted only sporadically. MRSA was clearly visible after 24 hours of incubation. Moreover, no MRSA could be detected after 48 hours of incubation if it was not already visible after 24 hours on this medium. Overall, MRSA colonies were larger with a brighter zone of hemolysis compared to the MuellerHinton medium without ceftazidime, following the same incubation period. We conclude that our screening approach, consisting of obtaining cultures of all appropriate anatomical sites and the use of an enrichment broth plus a selective solid agar plate, yielded higher case-detection rates of this epidemic MRSA III-29 strain. However, it must be borne in mind that the optimal detection technique could be strain-dependent.