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Studies on multiple Pseudomonas aeruginosa isolates from individual burn patients by RFLP, O antigen serotyping and
I A Holder1, K Volpel, G Ronald
1Department of Surgery, University of Cincinnati College of Medicine, Ohio, USA.
Abstract:
Multiple isolates of Pseud. aeruginosa from individual burn patients were tested for antibiotic susceptibility-resistance patterns (antibiogram), O serotype lipopolysaccharide and chromosomal DNA restriction fragment length polymorphisms (RFLP) using a PAK pilin gene probe. Some patients were colonized by isolates identical by all three analytical procedures whereas other patients were found where multiple isolates were identical on the basis of serotype and antibiogram analysis, but different on the basis of RFLP analysis. Examples were found where multiple isolates from an individual patient appeared to be identical on the basis of serotyping and RFLP data, but different on the basis of antibiogram. Strains refractory to O serotyping could be characterized by RFLP type. These results indicate that RFLP analysis provides a valuable addition to routine serotyping and antibiogram studies on Pseud. aeruginosa isolates and that significant numbers of burn patients become co-colonized/co-infected with phenotypically diverse strains of this organism.
Insights
Pseudomonas aeruginosa strains from burn patients show diverse antibiotic resistance and genetic profiles. Restriction fragment length polymorphism (RFLP) analysis reveals co-colonization with multiple, distinct strains in many patients.
Area of Science:
- Clinical Microbiology
- Infectious Diseases
- Molecular Biology
Background:
- Pseudomonas aeruginosa is a significant opportunistic pathogen, particularly in burn wound infections.
- Understanding the genetic diversity and antimicrobial resistance patterns of P. aeruginosa isolates is crucial for effective patient management.
- Traditional methods like serotyping and antibiograms have limitations in fully characterizing strain diversity.
Purpose of the Study:
- To evaluate the utility of Restriction Fragment Length Polymorphism (RFLP) analysis in characterizing Pseudomonas aeruginosa isolates from burn patients.
- To compare RFLP with established methods such as O serotyping and antibiogram analysis.
- To investigate the extent of co-colonization with phenotypically diverse P. aeruginosa strains in individual burn patients.
Main Methods:
- Antibiotic susceptibility-resistance patterns (antibiogram) were determined for multiple P. aeruginosa isolates from individual burn patients.
- O serotype lipopolysaccharide analysis was performed.
- Chromosomal DNA Restriction Fragment Length Polymorphism (RFLP) analysis was conducted using a PAK pilin gene probe.
Main Results:
- Some patients harbored P. aeruginosa isolates identical across all three analytical methods (antibiogram, serotype, RFLP).
- Other patients showed isolates that were identical by serotype and antibiogram but distinct by RFLP, indicating genotypic diversity.
- Conversely, some isolates appeared identical by serotyping and RFLP but differed in antibiogram, highlighting phenotypic variability.
- RFLP analysis successfully characterized strains that were refractory to O serotyping.
- A significant number of burn patients were found to be co-colonized or co-infected with phenotypically diverse P. aeruginosa strains.
Conclusions:
- Restriction Fragment Length Polymorphism (RFLP) analysis is a valuable adjunct to routine serotyping and antibiogram studies for P. aeruginosa.
- RFLP provides a higher resolution for strain differentiation compared to serotyping and antibiograms alone.
- Burn patients frequently experience co-colonization or co-infection with multiple, genetically distinct strains of Pseudomonas aeruginosa.