[Antibiotic resistance and biofilm formation in Pseudomonas aeruginosa strains isolated from patients with urinary tract infections].

Altogether 118 Pseudomonas aeruginosa strains isolated from urine of patients with urinary tract infection were tested by the disk diffusion method for susceptibility to ciprofloxacin, ofloxacin, gentamicin, amikacin, colistin, meropenem, imipenem, piperacillin/tazobactam and ceftazidime. All strains were also screened for biofilm formation using a modified Christensen method. Eighty-eight, i.e., 74.6%, of the tested strains were resistant to ofloxacin, 86 (72.9%) to ciprofloxacin and 70 (59.3%) to gentamicin. Forty strains (33.9%) were resistant to imipenem, 42 strains (35.6%) to meropenem, 14 strains (11.9%) to amikacin, 2 strains (1.7%) to colistin, 35 strains (29.7%) to piperacillin/tazobactam and 41 strains (34.7%) to ceftazidime. Co-resistance to ofloxacin, ciprofloxacin and gentamicin was detected in 67 strains (56.8%) while 12 strains (10.2%) were resistant to most tested antibiotics, with the exception of amikacin and colistin. Biofilm formation was found in 41 strains (34.7%), more precisely in 23 of 46 inpatient strains and 18 of 72 outpatient strains. Eight (66.6%) of 12 polyresistant strains were biofilm producers.