The new perspective of old antibiotic: In vitro antibacterial activity of TMP-SMZ against Klebsiella pneumoniae.

BACKGROUND/PURPOSE: Trimethoprim-sulfamethoxazole (TMP-SMZ) is broadly administered to treat multiple infections, and the paucity of effective treatment alternatives for infections caused by Klebsiella pneumoniae has led to a renewed interest in TMP-SMZ. The aim of this study is to evaluate the antibacterial efficacy of TMP-SMZ against K. pneumoniae.

METHODS

The resistance genes of K. pneumoniae clinical isolates were investigated by PCR, followed by conjugation experiments and multilocus sequence typing.

RESULTS

The resistance rate of K. pneumoniae to TMP-SMZ decreased over the collection period from 26.7% (88/330) to 16.9% (56/332). The high carrying rates (173/175, 98.9%) of resistance determinants (sul genes or dfr genes) were the main mechanisms of TMP-SMZ resistance isolates, with sul1 (142/175, 81.1%) and dfrA1 (119/175, 68.0%). Only class 1 integron was detected, the prevalence of which in TMP-SMZ resistant K. pneumoniae was 63.4% (111/175).

CONCLUSION

These results provided insights into the antimicrobial efficacy of TMP-SMZ against K. pneumoniae, also illustrating the wide distribution of SMZ and TMP resistance genes among resistant K. pneumoniae. Simultaneously, the present study highlights the significance of reasonable administration and effective continued monitoring.