Relation between resistance to beta-lactam antibiotics and cadmium in salmonellae isolated from pigs

Of 50 Salmonella species isolated from pigs, 30 were resistant to cadmium and 18 of these also to azlocillin. The azlocillin-resistant isolates were resistant to cadmium at 80-500 mg/L CdSO4. A broader spectrum of resistance to azlocillin, ampicillin and cephazolin was found in strains resistant to < 200 mg/L CdSO4. Resistance to silver, mercury, chloramphenicol and streptomycin was independent of the resistance to beta-lactam antibiotics and Cd2+. Production and levels of beta-lactamase do not correlate with the spectrum of resistance.