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Antimicrobial Resistance and Molecular Characterization of Staphylococcus aureus Causing Childhood Pneumonia in
Zhen Song1, Fei-Fei Gu2, Xiao-Kui Guo3
1Faculty of Laboratory Medicine, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine Shanghai, China.
Abstract:
Staphylococcus aureus or methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen causing pneumonia among children. To estimate the prevalence and molecular properties of S. aureus in children pneumonia in Shanghai, China, 107 hospitalized children with S. aureus pneumonia from two children's hospitals from January 2014 through June 2015 were studied. S. aureus isolates from the respiratory specimens were characterized by antimicrobial susceptibility, agr typing, toxin genes, multilocus sequence typing (MLST), spa, and SCCmec typing. Fifty-eight (54.2%, 58/107) were MSSA (methicillin-susceptible Staphylococcus aureus) and 49 (45.8%, 49/107) were MRSA. No isolates were found resistant to teicoplanin, sulfamethoxazole/trimethoprim, rifampicin, quinupristin/dalfopristin, linezolid, or vancomycin. However, these isolates showed high resistant rates to erythromycin, fosfomycin-trometamol and clindamycin. The agrI (87/107, 81.3%) was the most common agr allele, followed by agrIII(10/107, 9.3%), agrII(9/107, 8.4%), and agrIV(1/107, 0.9%). Six pvl-positive isolates (3 MRSA and 3 MSSA) and 7 isolates of livestock associated clone ST398 (4 MRSA, 3 MSSA) were identified. CC59 was found in 35 isolates (33 MRSA and 2 MSSA), constituting majority of MRSA (33/49, 67.35%). The dominant CC were CC59 (32.7%), CC188 (13.1%), CC7 (12.1%) and CC398 (9.3%) while t172 (16.8%), t189 (12.1%), t437 (9.3%), and t091 (9.3%) were the most common spa types. In conclusion, more particular concern should appeal to ST59-SCCmecIV-t172/t437 as it is the most common epidemic clone causing pneumonia among children in Shanghai.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA) are significant causes of childhood pneumonia in Shanghai. The ST59-SCCmecIV-t172/t437 clone is identified as the most prevalent epidemic strain.
Area of Science:
- Microbiology
- Infectious Diseases
- Pediatrics
Background:
- Staphylococcus aureus, including methicillin-resistant strains (MRSA), is a primary cause of pediatric pneumonia.
- Understanding the molecular epidemiology of S. aureus in children with pneumonia is crucial for effective treatment and control.
Purpose of the Study:
- To determine the prevalence and molecular characteristics of S. aureus isolates from children with pneumonia in Shanghai, China.
- To identify dominant clones and antimicrobial resistance patterns.
Main Methods:
- A study of 107 hospitalized children with S. aureus pneumonia was conducted.
- Isolates were analyzed for antimicrobial susceptibility, agr typing, toxin genes, MLST, spa, and SCCmec typing.
Main Results:
- The study identified 54.2% MSSA and 45.8% MRSA isolates.
- High resistance rates were observed for erythromycin, fosfomycin-trometamol, and clindamycin.
- The ST59-SCCmecIV-t172/t437 clone was the most common epidemic strain, particularly among MRSA isolates.
Conclusions:
- The ST59-SCCmecIV-t172/t437 clone poses a significant public health concern for pediatric pneumonia in Shanghai.
- Continued surveillance of S. aureus molecular epidemiology and resistance patterns is essential.