Antimicrobial resistance of Shigella isolates in Bangladesh, during 2001-2002, was studied and compared with that of 1991-1992 to identify the changes in resistance patterns and trends. A significant increase in resistance to trimethoprim-sulphamethoxazole (from 52% to 72%, p<0.01) and nalidixic acid (from 19% to 51%, p<0.01) was detected. High, but unchanged, resistance to tetracycline, ampicillin, and chloramphenicol, low resistance to mecillinam (resistance 3%, intermediate 3%), and to emergence of resistance to azithromycin (resistance 16%, intermediate 62%) and ceftriaxone/cefixime (2%) were detected in 2001-2002. Of 266 recent isolates, 63% were resistant to ≥3 anti- Shigella drugs (multidrug-resistant [MDR]) compared to 52% of 369 strains (p<0.007) in 1991-1992. Of 154 isolates tested by E-test in 2001-2002, 71% were nalidixic acid-resistant (minimum inhibitory concentration [MIC] ≥32 μg/mL) and had 10-fold higher MIC 90 (0.25 μg/mL) to ciprofloxacin than that of nalidixic acid-susceptible strains exhibiting decreased ciprofloxacin susceptibility, which were detected as ciprofloxacin-susceptible and nalidixic acid-resistant by the disc-diffusion method. These strains were frequently associated with MDR traits. High modal MICs were observed to azithromycin (MIC 6 μg/mL) and nalidixic acid (MIC 128 μg/mL) and low to ceftriaxone (MIC 0.023 μg/mL). Conjugative R-plasmids-encoded extended-spectrum ß-lactamase was responsible for resistance to ceftriaxone/cefixime. The growing antimicrobial resistance of Shigella is worrying and mandates monitoring of resistance. Pivmecillinam or ciprofloxacin might be considered for treating shigellosis with caution.
【저자키워드】 Azithromycin, Bangladesh, ciprofloxacin, Shigella, nalidixic acid, R-plasmid, Drug resistance, Microbial, Microbial sensitivity tests, E-test,