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Activity of the antiseptic polyhexanide against meticillin-susceptible and meticillin-resistant Staphylococcus aureus
1Institut für Medizinische Mikrobiologie, Virologie und Krankenhaushygiene, Universität Rostock, Schillingallee 70, D-18057 Rostock, Germany.
Abstract:
Staphylococcus aureus is one of the most important pathogens, with increasing emergence of meticillin-resistant S. aureus (MRSA) strains. This is associated not only with multiresistance to antibiotics but also with increasing resistance to topical antibiotics and antiseptics. As the antiseptic polyhexanide has only a low risk of emergence of resistant strains, the aim of the study was to obtain data on the sensitivity of S. aureus towards polyhexanide. The effect of polyhexanide was tested against 80 meticillin-susceptible S. aureus (MSSA) and 80 MRSA strains from sporadic cases as well as against 6 MRSA outbreak strains. The clonal diversity of the 166 strains was proven by pulsed-field gel electrophoresis (PFGE). Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined by the serial broth microdilution technique according to DIN 58940. Time-kill studies were performed for reference strains MSSA ATCC 29213 and MRSA ATCC 33591. MICs and MBCs in the range of 0.5-2mg/L were found. According to a created epidemiological cut-off (ECOFF) value of 4mg/L, all strains were regarded as susceptible to polyhexanide, including MRSA epidemic strains and MSSA and MRSA sporadic strains with various antibiotic susceptibility patterns. Addition of up to 4% albumin to the test medium did not change the MICs and MBCs. Time-kill studies showed reduction rates of 4log10CFU/mL for 200mg/L and 5log10CFU/mL for 400mg/L polyhexanide within 5-30min. It is concluded that polyhexanide is suitable for topical eradication of S. aureus.
Insights
Polyhexanide demonstrates high efficacy against Staphylococcus aureus, including antibiotic-resistant MRSA strains. This antiseptic shows a low risk of resistance development, making it suitable for topical eradication of S. aureus infections.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA), is a significant pathogen with increasing resistance to antibiotics and topical agents.
- The emergence of resistant strains necessitates the evaluation of antiseptics with a low risk of resistance development, such as polyhexanide.
Purpose of the Study:
- To investigate the sensitivity of Staphylococcus aureus, including MRSA and methicillin-susceptible S. aureus (MSSA) strains, to the antiseptic polyhexanide.
- To determine the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of polyhexanide against a diverse collection of S. aureus strains.
Main Methods:
- Tested polyhexanide against 166 S. aureus strains (80 MSSA, 80 MRSA, 6 MRSA outbreak strains) with confirmed clonal diversity via pulsed-field gel electrophoresis (PFGE).
- Determined MICs and MBCs using serial broth microdilution according to DIN 58940.
- Conducted time-kill studies on reference strains and evaluated the impact of albumin on efficacy.
Main Results:
- All tested S. aureus strains, including MRSA and MSSA, were susceptible to polyhexanide, with MICs and MBCs in the range of 0.5-2 mg/L.
- An epidemiological cut-off (ECOFF) value of 4 mg/L confirmed susceptibility across all strains, irrespective of antibiotic resistance patterns or clonal origin.
- Albumin did not affect polyhexanide's MICs or MBCs, and time-kill studies showed rapid bacterial reduction at concentrations of 200-400 mg/L.
Conclusions:
- Polyhexanide exhibits potent bactericidal activity against a wide spectrum of Staphylococcus aureus strains, including highly resistant MRSA.
- The low risk of resistance emergence and consistent efficacy in the presence of albumin support its use.
- Polyhexanide is a suitable agent for the topical eradication of S. aureus.
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