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[Mutations of gyrA gene and parC gene in Streptococcus pneumoniae]
Hitoshi Miyamoto1, Mitsuharu Murase
1Department Laboratories, Ehime University Hospital.
Abstract:
Fifty-six levofloxacin-susceptible strains of Streptococcus pneumoniae were isolated from various clinical material in July, 2002 from June, 2001, examined antimicrobial susceptibility testing of levofloxacin and sparfloxacin, and performed analysis of gyrA gene and parC gene. 56 strains were not sparfloxacin-resistance. There was not found to mutation of gyrA gene. However, the individual mutations of parC gene were accepted by 13 strains among 56 strains which showed sensitivity by levofloxacin. One strain was Asp-78-->Asn, other one strain was Ser-79-->Phe, and 11 strains were Lys-137-->Asn. These results suggest that fluoroquinolone-resistance could be due to the multiple mutations in gyrA gene and parC gene, although the individual mutation of parC gene existed also in levofloxacin-susceptible strains.
Insights
Levofloxacin-susceptible Streptococcus pneumoniae strains showed parC gene mutations, suggesting these alterations can occur even without fluoroquinolone resistance. Further research is needed to understand the full impact of these mutations.
Area of Science:
- Microbiology
- Genetics
- Pharmacology
Context:
- Levofloxacin and sparfloxacin are fluoroquinolone antibiotics used to treat bacterial infections.
- Streptococcus pneumoniae is a common cause of bacterial pneumonia and other infections.
- Antibiotic resistance is a growing global health concern.
Purpose:
- To investigate the genetic basis of fluoroquinolone susceptibility and resistance in Streptococcus pneumoniae.
- To analyze mutations in the gyrA and parC genes in levofloxacin-susceptible strains.
- To determine the prevalence of specific parC gene mutations in these strains.
Summary:
- Fifty-six levofloxacin-susceptible Streptococcus pneumoniae strains were tested for susceptibility to levofloxacin and sparfloxacin.
- Analysis revealed no mutations in the gyrA gene.
- However, 13 strains exhibited individual mutations in the parC gene, including Asp-78-->Asn, Ser-79-->Phe, and Lys-137-->Asn.
Impact:
- These findings indicate that mutations in the parC gene can be present in levofloxacin-susceptible Streptococcus pneumoniae.
- This suggests that fluoroquinolone resistance may arise from multiple genetic mutations, including those in parC.
- Understanding these genetic mechanisms is crucial for developing strategies to combat antibiotic resistance.