Transferable resistance to specific antibiotics in nosocomial strains of Pseudomonas aeruginosa from two teaching hospitals

We describe the transfer of resistance to kanamycin, carbenicillin and cephaloridine to a recipient strain of Escherichia-coli K-12 No. 3110 from three strains of Pseudomonas aeruginosa out of 146 strains tested in 1995, The P. aeruginosa No. 201, 203, 208 donor strains were isolated from patients in the University Clinics in Frankfurt, Germany. They were resistant to most beta-lactam antibiotics including cephalosporins of the 1st, 2nd and 3rd generation, imipenem, meropenem and aztreonam. They transferred kanamycin, carbenicillin and cephaloridine resistance determinants to recipient strain E. coli K-12 3110. These determinants were accompanied in strain P. aeruginosa No. 203, with a transfer of ceftazidime resistance determinants and in P. aeruginosa No. 208 with transfer of cefotaxime, ceftazidime and aztreonam resistance determinants. Transfer of-antibiotic resistance was also studied in 13 nosocomial strains of P. aeruginosa collected for their ceftazidime and/or imipenem resistance in a large Teaching Hospital in Ostrava, Czech Republic. Six of these strains transferred carbenicillin and/or cephaloridine resistance to the E. coli K-12 3110 recipient strain. Resistance to kanamycin and cefotaxime was also co-transferred with carbenicillin and cephaloridine determinants. Ceftazidime, imipenem or ofloxacin resistance was not transferred and is thus, most probably, of chromosomal origin.