M-GENOTYPING AND DNA-FINGERPRINTING OF STREPTOCOCCUS-PYOGENES ISOLATES FROM AN AREA OF CENTRAL ITALY

M protein gene typing was used to analyse Streptococcus pyogenes clini cal isolates collected between 1983 and 1995 in an area of central Ita ly from patients presenting different types of infections; the same is olates were also characterized by means of DNA fingerprinting. M type 1 was the most common (50 % of study strains), followed by M types 4, 12 and 6. The proportion of M type 12 decreased with time, whereas M t ype 1 increased, in agreement with data obtained in many different are as. Most invasive strains belonged to types M1 (30 %) and M12 (30 %); on the other hand, the M1 type did frequently occur also among noninva sive isolates. DNA fingerprinting showed a correlation between M types and DNA patterns. This report provides epidemiological information fr om a geographic area not sampled recently, and further shows the usefu lness of the M genotyping technique, which offers potential advantages over conventional serological typing methods.