[Wild-type and acquired resistance patterns of clinical isolates of Escherichia coli (author's transl)].

Stored data on the inhibition zone diameters of 2274 strains of Escherichia coli that had been determined during the first five investigation periods (1975 to 1977) of the Arbeitsgemeinschaft "Resistenz" using the standard disc susceptibility test on Mueller-Hinton agar, were evaluated for: (1) frequency of secondary resistance to ampicillin, carbenicillin, cephalothin, chloramphenicol, kanamycin, nitrofurantoin, streptomycin, sulfamethoxazole, tetracycline, and trimethoprim-sulfamethoxazole on the basis of statistically defined break points; (2) number, frequency, and qualitative characteristics of multiple resistance patterns; (3) regional distribution of the more common resistance patterns; (4) more detailed characterization of resistance patterns using the mean diameters of inhibition zones; and (5) occurrence of additional resistance determinants. The significance of such data in the epidemiological control of resistance to chemotherapeutics in gram-negative bacteria is discussed.