OBJECTIVE: In this study, it was aimed to investigate in vitro activity of moxifloxacin and rifampicin on biofilm formation by clinical MRSA isolates. BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) strains could be the causative agent in chronical and medical device associated infections by biofilm formation. METHODS: Moxifloxacin and rifampicin MIC values of 98 MRSA clinical isolates were determined by microdilution method. Biofilm formation of all isolates was determined in 96-well microplates by using spectrophotometric method. Effects of MIC and sub-inhibitory concentrations (1/2 and 1/4 MIC) of antibiotics on biofilm formation were examined in 46 strong biofilm producer strains. RESULTS: Biofilm production decreased in 37 and 44 isolates at all studied concentrations of moxifloxacin and rifampicin, respectively. Biofilm production increased in six isolates with moxifloxacin and in two isolates with rifampicin. CONCLUSION: Biofilm inhibitory effect of rifampicin was found to be stronger than moxifloxacin in the examined strains. The studied antimicrobials also induced biofilm formation in some strains. Results of this study may help to evaluate the effects of these antibiotics on biofilm formation of clinical MRSA strains and to control the antibiotic resistance in clinical settings (Tab. 2, Ref. 25).
OBJECTIVE: In this study, it was aimed to investigate in vitro activity of moxifloxacin and rifampicin on biofilm formation by clinical MRSA isolates. BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) strains could be the causative agent in chronical and medical device associated infections by biofilm formation. METHODS:Moxifloxacin and rifampicin MIC values of 98 MRSA clinical isolates were determined by microdilution method. Biofilm formation of all isolates was determined in 96-well microplates by using spectrophotometric method. Effects of MIC and sub-inhibitory concentrations (1/2 and 1/4 MIC) of antibiotics on biofilm formation were examined in 46 strong biofilm producer strains. RESULTS: Biofilm production decreased in 37 and 44 isolates at all studied concentrations of moxifloxacin and rifampicin, respectively. Biofilm production increased in six isolates with moxifloxacin and in two isolates with rifampicin. CONCLUSION: Biofilm inhibitory effect of rifampicin was found to be stronger than moxifloxacin in the examined strains. The studied antimicrobials also induced biofilm formation in some strains. Results of this study may help to evaluate the effects of these antibiotics on biofilm formation of clinical MRSA strains and to control the antibiotic resistance in clinical settings (Tab. 2, Ref. 25).
Authors: Agostinho Alves Lima-E-Silva; Renato Geraldo Silva-Filho; Henry Marcel Zalona Fernandes; Carmen Soares Meirelles Saramago; Alice Slotfeldt Viana; Maria José Souza; Eduardo Matos Nogueira Journal: Open Microbiol J Date: 2017-06-30