Compiled data on aminoglycoside, foremost netilmicin susceptibility of bacterial strains

The MIC-values of 73 bacterial strains isolated in Malmö from patients treated with netilmicin have been determined by the agar dilution method for five aminoglycosides: amikacin, gentamicin, netilmicin, sisomicin and tobramycin. The results are compared with those obtained with the disc diffusion method in another Swedish investigation, comprising 202 strains and with results obtained in other places. Among the strains isolated in the two Swedish investigations, Escherichia coli strains were most prevalent, 28 and 77 respectively, and in this group no important differences could be found except for sisomicin. The importance of the inoculum size was investigated in a separate study on 24 strains of the Malmö material. These strains had also been tested one year earlier, using another size of the inoculum. The comparison showed that an inoculum less than 10(4) colony forming units resulted in lower MIC-values.