Nationwide survey of antibiotic resistance by means of a computer. An introduction into the analysis of multiple antibiotic resistance.

One-year surveillance of single and multiple antibiotic resistance of 8 species of so-called "Problem Bacteria" by computer analysis of data obtained from 18 Public Health Laboratories in Slovakia in 1973 enables to establish the most frequently occuring spectra of multiple drug resistance which would point to the spread of typical R plasmids among the Problem bacteria investigated. As an introduction, we surveyed the mode of testing of Problem bacteria in individual PHLs against antibiotics - drugs of choice. Iw was important to find out whether strains belonging to Problem bacteria investigated are tested against sufficient number of antibacterial drugs. Our study shows that the percentage of bi- and multiple drug resistance in almost all bacterial species investigated depend on the number of antibiotics used in tests in vitro as single discs. The more antibiotic discs are used to test the strains, the more chance the laboratory has to register the true picture of multiresistance to antibiotics. Our study also shows that the testing in the PHLs associated to the computer study in this respect is inadequate. Moreover, the increasing complexity and proportion of multiple drug resistance in Problem Bacteria - with a notable exception of Salmonellae - forces the PHLs to use more and more discs so that using two Petri dishes full of discs - 12 to 15 discs - begins to be necessary in testing of most of the Problem bacteria under investigation.