Staphylococcus aureus strains exposed to copper indium sulfide quantum dots exhibit increased tolerances to penicillin G, tetracycline and ciprofloxacin
Semiconductor nanocrystals copper indium sulfide CuInS2 (CIS) have the qualities of low toxicity, high absorption coefficient and near-infrared luminescence, which make them gain growing attentions due to their wide prospective applications in fields. However, little is known about their potential biological effects including the underlying toxicity on environmental bacteria and microcosms in water, especially on pathogenic bacteria. In the work, two type pathogenic Staphylococcus aureus strains (S. aureus, CMCC 26003 and ATCC 25923) were used to investigate antibiotic resistance change of the bacteria to 14 kinds of antibiotics after they were exposed to intact CIS quantum dots or their weathered products. We found that, after exposed to certain concentrations of weathered CIS nanocrystals, S. aureus (CMCC 26003) increased tolerances to penicillin G, tetracycline and ciprofloxacin whereas S. aureus (ATCC 25923) remained relatively unchanged. Moreover, the CIS quantum dots exposed S. aureus (CMCC 26003) could return to the previous antimicrobial susceptibility level after the following one generated growth.