[Resistance to chemotherapeutic agents in strains of Salmonella isolated during the period of 1977-1979].

A study was carried out on the incidence and spectrum of resistance to chemotherapeutical agents of 500 Salmonella strains isolated from coprocultures during the period from April 1977 to April 1979. The 368 strains isolated from patients were tested against 13 agents and the 132 strains isolated from carriers against 7 chemotherapeutical agents, using the Kirby-Bauer method in both categories. A proportion of 58.7% of the patients were resistant to one or several chemotherapeutics, and only 27.2% of the carriers. As regards the entire lot of 500 strains in terms of their resistance to 7 chemotherapeutical agents, 226 (45.2%) were resistant to at least one antimicrobial product. All the strains were sensitive to Polymixin B; 31,4% were resistant to Ampicillin. 20 to 22% resistant to Kanamycin, Chloramphenicol and Tetracyclin. The strains presented the highest resistance to Sulphafurazol (46.2%). The tested strains belonged to 18 serotypes. S. agona proved highly resistant (100%), followed by S. bovis morbificans (78%) (most of the strains being resistant only to Furazolidon), S. heidelberg 63% and S. typhi murium 32%. Of the resistance patterns, the most frequent was: Ampicillin, Carbenicillin, Cephalotin, Streptomycin, Kanamycin, Chloramphenicol, Tetracyclin, Sulphafurazol encountered in S. agona. The plasmid nature of resistance to antibiotics was tested using as acceptor E. coli Hfr H. The transferable character of resistance was demonstrated in 34 of the 35 experimentally exposed strains. As a rule the transfer of resistance determinants occurred in its totality.