Phenotypic and genotypic characteristics of clinical isolates of pseudomonas aeruginosa: Rate of occurrence and distribution of different serotypes, antimicrobial susceptibility profiles, and molecular typing

Abstract

Background: In the current investigation, 167 clinical isolates of Pseudomonas aeruginosa obtained from a Northwest Ohio hospital were tested for phenotypic diversity using serotyping and antibiotic susceptibility testing. The genetic diversity of the selected strains was determined by DNA fingerprinting. Methods: The isolates were serotyped by slide agglutination. The susceptibility was measured by disk diffusion. To analyze genetic variability, 96 strains (serotypes O:1, O:2, O:6, and O:11) were studied by polymerase chain reaction (PCR)-based single primer DNA fingerprinting. Results: Of the 167 isolates, 25 strains were not typable, and serotypes O:8, O:12, O:13, and O:17 were not detected. Serotype O:11 was the most frequently encountered. Fifty strains were resistant to aztreonam, 35 strains to ciprofloxacin, 33 strains to gentamicin, 20 strains to tobramycin, 18 strains to ceftazidime, 14 strains to piperacillin, and 5 strains to amikacin. Multidrug resistance was high among serotypes O:15, O:4, O:2, and O:11. The majority of stains (≥80%) showed unique genotypes. Conclusions: Our data showed a high degree of phenotypic and genotypic diversity among these P. aeruginosa isolates.