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Sensitivity of Staphylococcus aureus, isolated from skin infections in 1994, to 19 antimicrobial agents
S Nishijima1, M Nakagawa, T Sugiyama
1Division of Dermatology, Kansai Medical University Kori Branch Hospital, Osaka, Japan.
Abstract:
The most common pathogen causing skin infections is Staphylococcus aureus and the incidence of multiply resistant strains of S. aureus has been increasing. The in vitro susceptibility of 130 isolates of S. aureus to 19 antimicrobial agents: ampicillin (ABPC), methicillin, cefaclor, cefpodoxime proxetil, gentamicin, erythromycin, clindamycin, minocycline, vancomycin, fusidic acid, norfloxacin, ofloxacin, enoxacin, ciprofloxacin, lomefloxacin, tosufloxacin, sparfloxacin, nadifloxacin and grepafloxacin, was evaluated by agar dilution tests. The S. aureus isolates were isolated from 130 patients with skin infections in 1994. The proportion of methicillin-resistant S. aureus isolates among the strains isolated was 19.2%. The concentration needed to inhibit 50% of the isolates was 3.13 mg/ml or less for all of the drugs, but the concentration needed to inhibit 90% of isolates was over 12.5 micrograms/ml, except in the cases of minocycline, vancomycin, fusidic acid, tosufloxacin and nadifloxacin. Tosufloxacin and nadifloxacin had the lowest minimum inhibitory concentrations. None of the S. aureus strains was resistant to nadifloxacin.
Insights
Staphylococcus aureus causes common skin infections, with increasing multiply resistant strains. Nadifloxacin and tosufloxacin showed the lowest minimum inhibitory concentrations against S. aureus isolates, with no resistance observed to nadifloxacin.
Area of Science:
- Microbiology
- Dermatology
- Infectious Diseases
Background:
- Staphylococcus aureus is a primary cause of skin infections.
- Increasing incidence of multiply-resistant Staphylococcus aureus strains poses a significant public health challenge.
- Understanding antimicrobial susceptibility is crucial for effective treatment strategies.
Purpose of the Study:
- To evaluate the in vitro susceptibility of Staphylococcus aureus isolates from skin infections to 19 antimicrobial agents.
- To identify antimicrobial agents with potent activity against contemporary S. aureus strains, including methicillin-resistant strains.
Main Methods:
- Agar dilution tests were employed to determine the susceptibility of 130 S. aureus isolates.
- Isolates were obtained from patients with skin infections in 1994.
- Minimum Inhibitory Concentrations (MICs) were determined for 19 different antimicrobial agents.
Main Results:
- 19.2% of the S. aureus isolates were identified as methicillin-resistant S. aureus (MRSA).
- Minocycline, vancomycin, fusidic acid, tosufloxacin, and nadifloxacin were effective in inhibiting 90% of isolates at concentrations ≤12.5 µg/ml.
- Tosufloxacin and nadifloxacin exhibited the lowest minimum inhibitory concentrations, with no observed resistance to nadifloxacin among the tested S. aureus strains.
Conclusions:
- Nadifloxacin and tosufloxacin demonstrate significant in vitro activity against Staphylococcus aureus, including methicillin-resistant strains.
- These agents represent promising therapeutic options for managing S. aureus skin infections.
- Continued surveillance of antimicrobial resistance patterns is essential for guiding clinical practice.