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Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA
Published on: February 9, 2011
Molecular Characteristic and Virulence Gene Profiles of Community-Associated Methicillin-Resistant Staphylococcus
1Department of Laboratory Medicine, Shanghai Children's Medical Center, Shanghai Jiaotong University School of Medicine Shanghai, China.
Abstract:
Staphylococcus aureus is a globally important human pathogen, especially among children and immunocompromised patients. The emergence and spread of community-associated methicillin-resistant S. aureus (CA-MRSA) has become a serious public health problem worldwide. The aim of this study was to investigate the prevalence, molecular characteristics and virulence profiles of CA-MRSA infections from pediatric patients in a university hospital in Shanghai, China. A total of 80 CA-MRSA isolates were collected from July 2012 to December 2013 in Shanghai Children's Medical Center and analyzed by multilocus sequence typing, staphylococcus chromosomal cassette mec (SCCmec) typing, and spa typing. The detection of Panton-Valentine Leukocidin (pvl), superantigenic and exfoliative toxins, and adhesin genes was also performed. Overall, 16 distinct sequence types (STs) were identified among the 80 isolates. Among them, ST59 was found to be the most prevalent, followed by ST398 (11.3%, 9/80) and ST88 (8.8%, 7/80). SCCmec types IV and V were observed, at 60 and 40%, respectively. Thirty spa types were identified, spa t437 (23.8%) was the most predominant type. All 80 isolates exhibited carriage of at least four virulence genes. Thirty-four (42.5%, 34/80) isolates harbored ≥10 tested virulence genes. Adhesion genes were present in most of the MRSA isolates, including the following: icaA (100%), clfA (100%), sdrC (95%), and sdrE (63.8%). The prevalence of pvl gene was 20%, and multidrug resistance was observed in 36% of all strains. In addition, ST59-MRSA-IV with t437 accounted for 21.3% of occurrences, making it the most prevalent clone. Isolates that were carriers of toxin genes, and hla (100%) and hlg (87.5%) were the most frequent. In conclusion, simultaneous carriage of multiple virulence genes and genetically considerable diversity were very common among CA-MRSA from pediatric patients in Shanghai. ST59-MRSA-IV with t437 was still the most predominant type. The combination of virulence gene profiles and antibiotic resistance may help ST59 to be successfully spread among children.
Insights
Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) in Shanghai children shows high genetic diversity and virulence. ST59-MRSA-IV with spa type t437 is the most common clone, often carrying multiple virulence genes and exhibiting antibiotic resistance.
Area of Science:
- Microbiology
- Infectious Diseases
- Public Health
Background:
- Staphylococcus aureus is a significant human pathogen, particularly in children.
- Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) poses a growing global health threat.
- Understanding CA-MRSA epidemiology in pediatric populations is crucial for effective control.
Purpose of the Study:
- To determine the prevalence and molecular characteristics of CA-MRSA in pediatric patients in Shanghai.
- To analyze the virulence gene profiles and antibiotic resistance patterns of these isolates.
- To identify dominant CA-MRSA clones and their potential for spread.
Main Methods:
- Collected 80 CA-MRSA isolates from pediatric patients (July 2012-December 2013).
- Performed multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing, and spa typing.
- Detected virulence genes including Panton-Valentine Leukocidin (pvl), adhesion genes, and toxin genes.
Main Results:
- Identified 16 distinct sequence types (STs), with ST59 being the most prevalent.
- SCCmec types IV (60%) and V (40%) were observed.
- ST59-MRSA-IV with spa type t437 was the predominant clone (21.3%).
- All isolates carried at least four virulence genes; 42.5% carried ≥10.
- The pvl gene was present in 20% of isolates, and 36% showed multidrug resistance.
Conclusions:
- CA-MRSA in Shanghai pediatric patients exhibit significant genetic diversity and carry multiple virulence genes.
- The ST59-MRSA-IV/t437 clone is the most prevalent and may be successful due to its virulence and resistance profiles.
- These findings highlight the need for ongoing surveillance and targeted interventions against CA-MRSA in children.
