Characteristics of own collection of Pseudomonas aeruginosa clinical strains, hosts of bacteriophages

Abstract

Introduction: The paper presents the phenotypic and molecular characteristics of the collection of 18 P. aeruginosa clinical isolates used as host indicators to study the lytic range of 12 phages against P. aeruginosa. Methods: The phages host ranges were assayed by spot tests. Phenotypic characteristics of strains was investigated by the API 20NE biochemical fingerprinting, oxidase tests, the production of pyocyanin, fluorescein and L-arginine dihydrolase. Resistance profiles were analyzed. The PCR method and sequencing were used to study the distribution the genes of alkaline protease (aprA), exotoxin A (exoA), elastase B (lasB), exotoxins (exoS/T/U/Y), phenazine modyfing genes (phzM, phzS) and to identify selected β-lactamases (blaGES, blaIMP, blaKPC, blaOXA-2, blaOXA-10, blaPER, blaSPM-1, blaSHV, blaTEM, blaVIM). Additionaly, the genetic diversity was investigated by PFGE.116 M. Brzychczy-Włoch i inni Nr 2-4 Results: Twenteen newly isolated P. aeruginosa phages were found to lyse 100% of the analyzed strains. Phages PAR_3 and PAR_10 exhibited the highest lytic activity against isolates, lysing, 77,8% strains tested. The other phages, PAR_9 and PAR_12, presented generally weaker activity against bacteria, lysing respectively, 50% and 44,4% of tested strains. AprA, exoA, phzM, phzS were presented in all strains; lasB in 77,8%. The most frequentlycombination of egzoenzyme genes S+/T+/U-/Y+ in 78% isolates was remarked. In collection, 18 different resistance profiles were observed and 44% isolates were classified as MDR. The blaGES was the most prevalent gene (44%), followed by blaSPM-1 and blaTEM detected in 17% and 11,1% isolates, respectively. BlaOXA-2 was detected in only 5,5% of all isolates. In PFGE method, 18 singletons (A-S) were identified. No relationship between resistance, virulence and PFGE groups was found. Conclusion: In summarize, all phages infect multiple host species and showed a broad lytic spectrum. All bacteria tested were infected by multiple phages and displayed a wide range of susceptibility. In general, we observed a high degree of genetic diversity and individuality of the studied P. aeruginosa collection, bacteriophage hosts.