Microbiological Characteristics of Clinically Isolated with Different Hemolytic Phenotypes in China.

PURPOSE

This study aimed to investigate the microbiological characteristics of clinically isolated with different hemolytic phenotypes in China.

MATERIALS AND METHODS

Using the three-point inoculation method, the hemolytic phenotypes of 1295 clinically isolated strains were detected and categorized. Antimicrobial susceptibility testing of all strains was performed using a VITEK 2 Compact System. After sample size matching, plasma coagulase activity, catalase activity, mRNA expression of hemolysin genes (, and ), biofilm formation, growth kinetics, inflammatory response of macrophages and cytotoxicity of with different hemolytic phenotypes using the rabbit plasma kit, the catalase test on slides, qRT-PCR, crystal violet staining, the microcultivation assay, the ELISA kits, and the CCK-8 assay, respectively.

RESULTS

Seven categories of hemolytic phenotypes were identified. Accordingly, strains were categorized into seven different groups, including with complete hemolytic phenotype (SCHP), with weak hemolytic phenotype (SWHP), with incomplete hemolytic phenotype 1 (SIHP-1), SIHP-2, SIHP-3, SIHP-4 and SIHP-5, the last three of which were reported for the first time. Except for the hemolytic phenotype, all seven groups differed in clinical isolation rates, antibiotic resistance profile, plasma coagulase activity, mRNA expression of hemolysin genes, biofilm formation, growth kinetics, inflammatory response of macrophages, and cytotoxicity.

CONCLUSION

with different hemolytic phenotypes have distinctive microbiological characteristics. Clinical microbiologists need to be vigilant about the hemolytic phenotypes when culturing strains, and actively enhance communication with clinicians to optimize the treatment of infection.