Quinolone-resistant Shigella flexneri Isolated in a Patient Who Travelled to India

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.

Gastroenteritis in Japanese Females Caused by Shigella flexneri without Definite Infection Route: A Case Report and Mini-Review of Literature

“…Here, several mechanisms are responsible for the development of antimicrobial resistance in Shigella strains [46]. One prominent mechanism is the mutation of the genes related to antimicrobial resistance [46]. For example, about quinolone resistance, the target regions where mutations occur in the organism have been identified as topoisomerase IV (parC and parE) and DNA gyrase (gyrA and gyrB) [18,46].…”

“…Patients are often treated with antimicrobial agents to reduce the duration of illness, and the treatment is known to reduce the period of Shigella excretion [46]. Antibiotic susceptibility testing should be performed at the time of stool and/or blood culture, and at the start of outbreak; and antibiotic use should be restricted to cases of Shigella classified as severe based on resistance pattern variations observed in different regions [24].…”

“…Multi-drug-resistant Shigella, including extended spectrum β-lactamases producing Shigella, is also emerging; and has the potential to become a serious threat to public health [11]. Here, several mechanisms are responsible for the development of antimicrobial resistance in Shigella strains [46]. One prominent mechanism is the mutation of the genes related to antimicrobial resistance [46].…”

“…Although antimicrobial susceptibility was considerably high to most commonly used drugs, genetic determinants were variable between countries over time; therefore, the data stress the need for a more careful selection of antibiotics in the treatment of shigellosis [47]. The majority of S. flexneri is sensitive to 3rd generation cephalosporins, and quinolones, especially ciprofloxacin, are commonly employed in the treatment of shigellosis [36,46]. However, in recent years, some Shigella strains have rapidly developed resistance to antimicrobial agents [9,23,46,48].…”

“…The majority of S. flexneri is sensitive to 3rd generation cephalosporins, and quinolones, especially ciprofloxacin, are commonly employed in the treatment of shigellosis [36,46]. However, in recent years, some Shigella strains have rapidly developed resistance to antimicrobial agents [9,23,46,48]. For example, more than 80.0% of isolates of S. flexneri have proven resistant to ampicillin, nalidixic acid, and tetracycline; and in China from 2004 to 2014, Shigella isolates were highly resistant to nalidixic acid (89%), ampicillin (89%), tetracycline (88%), and sulfamethoxazole (83%).…”