High genotypic diversity of Pseudomonas aeruginosa strains isolated from patients with cystic fibrosis in the Czech Republic

Over the last decade, epidemic and frequently multidrug-resistant Pseudomonas aeruginosa has increasingly been found among European cystic fibrosis (CF) patients. In the Czech Republic, more than half of the registered CF patients attend the Prague CF centre. At this centre, a Burkholderia cenocepacia strain was recently found to have spread among the patients. The aim of the present study was to assess whether P. aeruginosa isolates from patients at this centre were also genetically related and, if so, whether they were multidrug-resistant. We investigated a collection of 69 isolates from as many patients who represented 80% of the total number of P. aeruginosa-positive patients in 2004. The organisms were typed by AFLP and SpeI macrorestriction analyses (PFGE). Using these methods, 44 unique strains and nine groups of two to five isolates each were distinguished. Among these groups, two each had a prevalence of 7% in the patient population, while others had a prevalence of ≤3%. The diversity observed with PFGE was largely in agreement with the diversity found by AFLP analysis. All isolates were susceptible to colistin; 94–96% were susceptible to piperacillin, ceftazidime, cefepime, meropenem, amikacin or tobramycin; and 84–87% were susceptible to ciprofloxacin, gentamicin or netilmicin. In conclusion, the organisms recovered from Czech CF patients showed high genotypic diversity and good susceptibility to antipseudomonal agents. The absence of highly epidemic P. aeruginosa strains may result from infection control measures taken upon recognition of the epidemic B. cenocepacia.