ABSTRACT
Objective To evaluate the bacteriostasis of sulfamethoxazole(SMZ)combined with trimethoprim(TMP)against My‐cobacterium tuberculosis(MTB) in vitro ,so as to provide basis for clinical application .Methods The minimal inhibitory concentra‐tion(MIC) value of TMP/SMZ against MTB ,including standard sensitive strain(H37Rv) ,clinical sensitive strains(20 strains) and clinical multiple‐drug‐resistance strains(MDR ,30 strains) ,was detected by using MPP observation method .Results The MIC val‐ue of standard strain H37Rv was TNP(0 .5 μg/mL)+SMZ(9 .5 μg/mL) .The growth of 40 strains(accounted for 80% ) of clinical isolates ,including 17 sensitive strains and 23 MDR strains ,could be inhibited by TMP(1 μg/mL)+ SMZ(19 μg/mL) compound . Conclusion TMP combined with SMZ may has good antibacterial activity for strains of MTB in vitro .
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 follow:MIC≤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 .