Minimum inhibitory (MIC) and minimum microbicidal concentration (MMC) of polihexanide and triclosan against antibiotic sensitive and resistant Staphylococcus aureus and Escherichia coli strains.

BACKGROUND: An in-vitro study was conducted investigating the antimicrobial efficacy of polihexanide and triclosan against clinical isolates and reference laboratory strains of Staphylococcus aureus and Escherichia coli. METHODS: The minimal inhibitory concentration (MIC) and the minimal microbicidal concentration (MMC) were determined following DIN 58940-81 using a micro-dilution assay and a quantitative suspension test following EN 1040. Polihexanide was tested in polyethylene glycol 4000, triclosan in aqueous solutions. RESULTS: Against all tested strains the MIC of polihexanide ranged between 1-2 µg/mL. For triclosan the MICs varied depending on strains ranging between 0.5 µg/mL for the reference strains and 64 µg/mL for two clinical isolates. A logRF >5 without and logRF >3 with 0.2% albumin burden was achieved at 0.6 µg/mL triclosan. One exception was S. aureus strain H-5-24, where a triclosan concentration of 0.6 µg/mL required 1 minute without and 10 minutes with albumin burden to achieve the same logRFs. Polihexanide achieved a logRF >5 without and logRF >3 with albumin burden at a concentration of 0.6 µg/mL within 30 sec. The exception was the North-German epidemic MRSA strain, were an application time of 5 minutes was required. CONCLUSION: The clinical isolates of E. coli generally showed higher MICs against triclosan, both in the micro-dilution assay as well in the quantitative suspension test than comparable reference laboratory strains. For polihexanide and triclosan strain dependant susceptibility was shown. However, both antimicrobial compounds are effective when used in concentrations common in practice.

High prevalence of the ermB gene among erythromycin-resistant streptococcus pneumoniae isolates in Germany during the winter of 2000-2001 and in vitro activity of telithromycin.

Of 595 isolates of Streptococcus pneumoniae from outpatients with respiratory tract infections, collected from 17 microbiology laboratories, 14.1% were resistant to erythromycin. Eighty-three erythromycin-resistant isolates were genetically analyzed, 83.1% of which harbored the ermB gene. Only four isolates (4.8%) harbored the mefA gene. Telithromycin exhibited potent activity against all isolates.

Extension of in-use stability of preservative-free nasalia.

Nasal drops and nasal sprays are commonly supplied in multi-dose containers that usually include suitable levels of an appropriate preservative in order to kill or prevent growth of any microorganisms which might enter the dispensing system. Preservatives should both protect the patient from infection and prevent spoilage of the product. Unfortunately, preservatives often cause unwanted side effects; in particular, the nasal mucosa is irritated frequently. Consequently, the use of preservatives in nasal preparations should be avoided. The technical design of the 3K system, a new multi-dose container, combines several microbiological safety features and therefore allows use without preservatives. Earlier tests have shown its safety for 6 weeks after the first opening. In order to test the microbiological safety of this multi-dose system over longer time periods, an in-use stability test was designed. The results revealed that the first dose as well as the contents complied with the requirements of the European Pharmacopoeia. Therefore, from a microbiological point of view for the tested nasalia in the 3K system, the stability after opening could be extended from 6 weeks up to several months without loss of microbiological quality.