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Updated: Aug 8, 2025
Quantifying the Cytotoxicity of Staphylococcus aureus Against Human Polymorphonuclear Leukocytes
Published on: January 3, 2020
Correlation Analysis of Staphylococcus aureus Drug Resistance and Virulence Factors with Blood Cell Counts and
Jing Wei1, Kaihui Ma2, Yuan Zhang1
1Department of Laboratory Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, Jiangsu, China.
Objective:
The influence of different Staphylococcus aureus variants on blood cells and coagulation system was evaluated by investigating the carrying status of drug resistance genes and virulence genes of methicillin-resistantStaphylococcus aureus (MRSA) and methicillin-sensitiveStaphylococcus aureus (MSSA).
Methods:
A total of 105 blood culture-derivedStaphylococcus aureus strains were collected. The carrying status of drug resistance genes mecA and three virulence genes tst, pvl, and sasX was analyzed by polymerase chain reaction (PCR). The changes in routine blood routine counts and coagulation indexes of patients infected with different strains were analyzed.
Results:
The results showed that the positive rate of mecA was consistent with that of MRSA. Virulence genes tst and sasX were detected only in MRSA. Compared with MSSA, patients infected with MRSA or MSSA patients infected with virulence factor, leukocyte count and neutrophil count in peripheral blood were significantly increased, and the platelet count decreased to a higher degree. Part thromboplastin time increased, D-dimer increased, but fibrinogen content decreased more. The changes of erythrocyte and hemoglobin had no significant correlation with whether Staphylococcus aureus carried virulence genes.
Conclusion:
The detection rate of MRSA in patients with positive Staphylococcus aureus in blood culture had exceeded 20%. The detected MRSA bacteria carried three virulence genes, tst, pvl, and sasX, which were more likely than MSSA. MRSA, which carries two virulence genes, is more likely to cause clotting disorders.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) strains, unlike MSSA, carry specific virulence genes and are linked to significant changes in blood cell counts and coagulation. MRSA infections are associated with increased clotting disorders.
Area of Science:
- Microbiology and Infectious Diseases
- Hematology
- Clinical Pathology
Background:
- Staphylococcus aureus is a common pathogen with varying strains, including methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) types.
- Understanding the genetic basis of virulence and drug resistance in S. aureus is crucial for predicting clinical outcomes.
Purpose of the Study:
- To investigate the influence of different Staphylococcus aureus variants (MRSA vs. MSSA) on blood cell counts and the coagulation system.
- To analyze the carriage of specific drug resistance and virulence genes in these strains.
Main Methods:
- Collected 105 blood culture-derived Staphylococcus aureus strains.
- Utilized polymerase chain reaction (PCR) to detect mecA, tst, pvl, and sasX genes.
- Analyzed routine blood counts and coagulation indexes in infected patients.
Main Results:
- MRSA strains showed a higher prevalence of virulence genes (tst, sasX) compared to MSSA.
- Patients infected with MRSA or virulent MSSA exhibited increased leukocyte and neutrophil counts, and decreased platelet counts.
- Coagulation changes included prolonged partial thromboplastin time, elevated D-dimer, and decreased fibrinogen in MRSA/virulent MSSA infections.
Conclusions:
- MRSA detection in blood cultures exceeded 20%, with a higher likelihood of carrying virulence genes (tst, pvl, sasX).
- MRSA strains, particularly those with multiple virulence genes, are more frequently associated with the development of clotting disorders.
