Evaluation of methods for typing coagulase-negative staphylococci

Area of Science:

• Microbiology
• Epidemiology
• Infectious Diseases

Background:

• Coagulase-negative staphylococci (CNS) are significant pathogens in patients undergoing continuous ambulatory peritoneal dialysis (CAPD).
• Antibiotic resistance in CNS complicates CAPD patient management and necessitates accurate epidemiological surveillance.

Purpose of the Study:

• To evaluate the suitability of various supplementary typing methods for epidemiological studies of antibiotic resistance in CNS isolates from CAPD patients.
• To compare the discriminatory power and reproducibility of phage typing, plasmid typing, and whole-cell protein typing (SDS-PAGE, immunoblotting) against antibiogram-biotype profiles.

Main Methods:

• One hundred and forty-two CNS isolates from CAPD patients were characterized by extended antibiogram and biotype analysis.
• Supplementary typing methods included phage typing, reverse phage typing, plasmid typing, SDS-PAGE, and immunoblotting.
• Performance metrics evaluated included successful typing rates, discrimination, and reproducibility.

Main Results:

• Whole-cell protein typing methods (SDS-PAGE and immunoblotting) achieved 100% successful typing rates and high discrimination (69% and 57%, respectively).
• Antibiogram-biotype profiling showed insufficient accuracy for epidemiological studies.
• While technically demanding, SDS-PAGE and immunoblotting effectively identified errors in antibiogram-biotype based discrimination.

Conclusions:

• Standard antibiogram-biotype profiling is inadequate for accurate epidemiological surveillance of antibiotic resistance in CAPD-associated CNS infections.
• Whole-cell protein typing, particularly SDS-PAGE and immunoblotting, offers superior discriminatory power and reliability for such studies.
• Advanced molecular typing methods are crucial for understanding the epidemiology of antibiotic resistance in immunocompromised patient populations.