The relationship between Streptococcus pneumoniae biofilm formation and antibiotic resistance / 医学研究生学报

ABSTRACT

Objective Streptococcus pneumoniae can form biofilms .The aim of this study was to investigate the biofilm forma-tion of Streptococcus pneumoniae and the relationship with antibiotic resistance of penicillin etc . Methods A total of 147 clinical iso-lates of Streptococcus pneumoniae were collected from 7 teaching hospitals in Nanjing from 2010 to 2012.Minimal inhibitory concentration (MIC) of penicillin, erythromycin, cefuroxime and ceftriaxone were determined by agar dilution method .Streptococcus pneumoniae with various penicillin MIC was selected randomly as followMIC≤0.065μg/mL, 0.5μg/mL, 2μg/mL and≥4μg/mL, which was incuba-ted to form biofilms in 96-well plates and 24-well plates for 24 hours.The A values at 570 nm was measured and the biofilm was observed through confocal laser scanning microscope ( CLSM) . Results The biofilm semi-quantitative detection and CLSM both displayed that all strains formed biofilms.The A value of the group which penicillin MIC was ≤0.065μg/mL (0.228 ±0.063) was higher than the 0.5μg/mL group (0.200 ±0.061) and the≥4μg/mL group (0.186 ±0.050) (P0.05).The A value of the group which erythromycin MIC was ≤0.5μg/mL (0.211 ±0.068) was higher than the ≥4μg/mL group (0.201 ±0.052) (P>0.05).The A value of the group sensitive to cefuroxime (0.216 ±0.062) was higher than the group resistant to cefuroxime (0.196 ±0.054) (P<0.05). Conclusion Streptococcus pneumoniae can form biofilms .Streptococcus pneumoniae with high antibiotics MIC has a trend of weakened biofilm formation .