The quinolone class of antibiotics has become an integral component of the antimicrobial arsenal. However, the presence of plasmid-mediated quinolone resistance genes has been increasing in Enterobacteriaceae since the introduction of quinolones. This study aimed to fill a considerable gap in the literature by assessing the prevalence and type of plasmid-mediated quinolone resistance genes isolated from individuals living in Korea.

We investigated the ST distribution of bloodstream isolates of E. coli that were not susceptible to ciprofloxacin (CIP-NS isolates), collected from 2013 to 2014 in a tertiary care hospital. Fifty-nine CIP-NS isolates were collected. ST131 was the most frequent ST (37.3%) isolate, followed by ST1193 (23.7%). ST131 and ST1193 showed significant differences in ESBL production and lactose fermentation. Further study should be continued on the monitoring of resistant strains.

No abstract

We report a recent case in which ciprofloxacin-resistant Shigella flexneri was isolated from a 23-yr-old female patient with a history of travel to India. Prior to her admission to our internal medicine department, she experienced symptoms of high fever and generalized weakness from continuous watery diarrhea that developed midway during the trip. S. flexneri was isolated from the stool culture. Despite initial treatment with ciprofloxacin, the stool cultures continued to show S. flexneri growth. In the susceptibility test for antibiotics of the quinolone family, the isolate showed resistance to ciprofloxacin (minimum inhibitory concentration [MIC], 8 µg/mL), norfloxacin (MIC, 32 µg/mL), ofloxacin (MIC, 8 µg/mL), nalidixic acid (MIC, 256 µg/mL), and intermediate resistance to levofloxacin (MIC, 4 µg/mL). In molecular studies for quinolone resistance related genes, plasmid borne-quinolone resistance genes such as qnrA, qnrB, qnrS, aac(6')-Ib-cr, qepA, and oqxAB were not detected. Two mutations were observed in gyrA (248C→T, 259G→A) and 1 mutation in parC (239G→T). The molecular characteristics of the isolated S. flexneri showed that the isolate was more similar to the strains isolated from the dysentery outbreak in India than those isolated from Korea.

Tuberculosis due to infection with