[Resistance against antibiotics in routine isolates of bacteria in seven regional Public Health Laboratories.]

In 1990-1992 seven regional Public Health Laboratories sent the results of all their routine determinations of antibiotic susceptibility to the RIVM. Each year data from approximately 125000 isolates were collected on floppy disks. During the investigation no striking changes in the level of resistance occurred. Although regional differences in the level of resistance were observed, these may have been due to differences in the methods applied. Escherichia coli, Staphylococcus aureus, enterococci and coagulase-negative staphylococci were the most frequently isolated bacteria. Resistance of Echerichia coli to amoxycillin, doxycycline and trimethoprim was between 20 and 35%. The new cephalosporins, quinolones and aminoglycosides were still active aginst virtually all Enterobacteriaceae. Resistance of Staphylococcus aureus against beta-lactamase-stable beta-lactam antibiotics was rare (a few percent at most). Resistance was most frequent in enterococci and coagulase-negative staphylococci. The number of isolates for each species or group of species and the percentages of resistance have been compared with the results of other investigations. Our results were similar to those of a similar British survey, whereas in the US resistant bacteria were found more frequently. Also in many other European countries the level of resistance appeared higher.GH