Changes in resistance to aminoglycoside antibiotics of different bacterial strains isolated during the period 1978 to 1983. Netilmicin as alternative therapy.

The percentage resistance of 11,404 gram-negative and gram-positive bacterial strains isolated from different biological materials between 1978 and 1983 to some aminoglycoside antibiotics (gentamicin, tobramycin and amikacin) was determined. The percentage of resistant Pseudomonas, Staphylococcus and indole-positive Proteus organisms significantly increased. There was also a significant decrease in gentamicin-resistant strains of the Escherichia coli and Proteus mirabilis species. We also compared the in vitro activity of netilmicin (routinely tested from the beginning of 1983) with those of the other aminoglycosides against 1546 bacterial strains. Netilmicin was found to have greater antibacterial activity than gentamicin or tobramycin. In addition, netilmicin was active against 48.9% of the strains that were resistant to gentamicin and/or tobramycin.