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Published on: February 9, 2011
Isolation and characterization of Streptococcus mitis from blood of child with osteomyelitis
Ryota Nomura1, Kazuhiko Nakano, Katriina Mäkelä
1Department of Pediatric Dentistry, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan.
Objectives:
Osteomyelitis is an inflammatory process accompanied by bone destruction that is caused by bacterial infection, with most child cases showing a haematogenous origin and metaphysis of the long bones. The aim of the present study was to characterize streptococcal strains isolated from the blood of a child diagnosed with osteomyelitis in a long bone and investigate the biological properties related to virulence of strains associated with osteomyelitis.
Methods:
Blood isolate species were determined based on the 16S rRNA sequence. Next, the blood isolates were analysed for phagocytosis susceptibility by polymorphonuclear leukocytes, platelet aggregation, inhibitory effects on osteoblastic cells, and their properties of adhesion with cells, and compared to the reference strain Streptococcus mitis ATCC49456.
Results:
The blood isolates were found to be a single clone (named SA1101), which was determined to be S. mitis. The phagocytosis susceptibility of SA1101 was significantly lower than that of ATCC49456, while its platelet aggregation rate was higher. Furthermore, SA1101 showed an inhibitory effect toward the growth of osteoblastic cells and had greater properties of adhesion to those cells as compared to ATCC49456.
Conclusions:
These results suggest that S. mitis SA1101 is a possible etiological agent and caused osteomyelitis in the present case.
Insights
Streptococcus mitis SA1101, isolated from a child with osteomyelitis, exhibited increased platelet aggregation and adhesion to bone cells, suggesting its role in the infection.
Area of Science:
- Microbiology
- Infectious Diseases
- Orthopedics
Background:
- Osteomyelitis is bone inflammation and destruction, often bacterial.
- Pediatric cases frequently stem from bloodstream infections (hematogenous origin).
- Long bone metaphyses are common sites in children.
Observation:
- A specific Streptococcus mitis strain (SA1101) was isolated from a child's bloodstream.
- This strain demonstrated reduced susceptibility to phagocytosis by immune cells.
- SA1101 exhibited enhanced platelet aggregation compared to a reference strain.
Findings:
- The isolated S. mitis SA1101 inhibited osteoblast cell growth.
- SA1101 displayed superior adhesion properties to osteoblastic cells.
- Virulence factors like platelet aggregation and cell adhesion were elevated in SA1101.
Implications:
- S. mitis SA1101 is a potential etiological agent of osteomyelitis.
- Understanding these virulence factors can inform future treatment strategies.
- This case highlights the importance of identifying specific bacterial strains in pediatric osteomyelitis.
