OCCURRENCE AND ANTIBIOTIC-RESISTANCE OF PSEUDOMONAS SPECIES ISOLATED FROM DRINKING-WATER IN SOUTHERN GREECE

A total of 194 samples of drinking waters consisting of 88 tap waters and 106 non-carbonated bottled waters were processed for isolation of Pseudomonas species during a 4-month period according to standard meth ods. Pseudomonaas aeruginosa was the predominant isolated Pseudomonas specie. Twenty-eight (14.4%) P. aeruginosa were isolated from 194 samp les. Eight (9%) were isolated from 88 tap water samples and 20 (18.8%) from 106 bottled water samples. Eight (9%) tap waters yielded non-P. aeruginosa strains while bottled waters yielded 22 (20.7%) non-P. aeru ginosa strains (P < 0.05). Antibiotic-resistant strains of Pseudomonas species have been isolated from the drinking waters. All but Pseudomo nas stutzeri species had a multiple chloramphenicol-erythromycin resis tance phenotype. Streptomycin and tetracycline resistance for P. serug inosa was invariably accompanied by chloramphenicol, tetracycline, ery thromycin and nalidixic acid resistance. The susceptibility of Pseudom onas species to newer antimicrobial agents (beta lactams, aminoglycosi des, third generation cephalosporins and quinolones) was also evaluate d. Ceftazidime and ciprofloxacin seemed to be the most active molecule s. There were no resistant P. aeruginosa and P. stutzeri strains to al l newer antibiotics tested while Pseudomonas maltophilia was the most resistant among the tested species (69.2% resistance for the newer ant ibiotics).