Two hundred and twenty strains of Staphylococcus isolated in Naples, Italy, were surveyed for the distribution of the mecA, the structural gene for penicillin-binding protein 2a, which is the genetic determinant for methicillin-resistance in staphylococci. Screening by a cloned mecA, revealed that of 220 strains, 43 were methicillin-resistant (19.5%) and 177 were methicillin-susceptible (80.5%). Among the 43 resistant strains 23 (53.5%) carried mecA in their genome and 20 (46.5%) did not carry mecA, in spite of their resistance to methicillin. Every group was submitted to the AP-PCR profiling. A quantitative analysis of the patterns divided strains into four different clusters for methicillin-resistant mecA-negative and two different clusters for methicillin-resistant mecA-positive with primer 1, while no clusters were noted with primer 7. We conclude that these clinical isolates from our area, were not found to belong to a single clone, although the predominance of four methicillin-resistant mecA-negative genotypes were noted.