Ribotyping of coagulase-negative staphylococci

Area of Science:

• Clinical Microbiology
• Molecular Epidemiology
• Infectious Diseases

Background:

• Coagulase-negative staphylococci (CNS) are significant causes of peritoneal dialysis infections.
• Accurate strain typing is crucial for understanding the epidemiology of these infections.
• Established typing methods have limitations in discriminative capacity and applicability.

Purpose of the Study:

• To evaluate the discriminatory power of ribotyping for coagulase-negative staphylococci (CNS) isolates.
• To compare ribotyping with established methods for typing CNS from peritoneal dialysis infections.
• To assess the reproducibility and utility of ribotyping in clinical epidemiology.

Main Methods:

• Forty-eight CNS isolates from peritoneal fluids of 17 patients undergoing peritoneal dialysis were studied.
• DNA was digested with EcoRI or HindIII and ribotyped using a biotinylated cDNA probe for 16S + 23S rRNA gene sequences.
• Ribotyping results were compared with biotype-antibiotic resistogram (ARB), antibiotic resistogram, API-Staph, phage typing, and plasmid analysis.

Main Results:

• Ribotyping, in combination with other methods, identified 27 types, comparable to ARB (28 types).
• The method was highly reproducible and successfully typed all isolates, including non-phage-typable and plasmid-negative strains.
• Hierarchical application of ribotyping with ARB and other systems revealed additional strain types, highlighting its enhanced discriminatory capacity.

Conclusions:

• Ribotyping demonstrates significant discriminatory capacity for CNS isolates from peritoneal dialysis infections.
• It offers high reproducibility and can type isolates missed by other methods.
• Ribotyping is a valuable tool for specific epidemiological investigations or as an initial screening method.