Increasing spectrum in antimicrobial resistance of Shigella isolates in Bangladesh: resistance to azithromycin and ceftriaxone and decreased susceptibility to ciprofloxacin.

Authors:	Mahbubur Rahman, Shereen Shoma, Harunur Rashid, Shams El Arifeen, A H Baqui, A K Siddique, G B Nair, D A Sack
Language:	Eng.
Date:	07-11-2007
Journal:	Journal of health, population, and nutrition (1606-0997)
Release:	J Health Popul Nutr. 2007 Jun;25(2):158-67


Abstract:	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 > or =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] > or =32 microg/mL) and had 10-fold higher MIC90 (0.25 microg/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 microg/mL) and nalidixic acid (MIC 128 micdrog/mL) and low to ceftriaxone (MIC 0.023 microg/mL). Conjugative R-plasmids-encoded extended-spectrum beta-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.
Copyright:	Journal of health, population, and nutrition Laboratory Sciences Division, ICDDR,B GPO Box 128, Dhaka 1000 (Mohakhali, Dhaka 1212), Bangladesh. mahbubur@icddrb.org
Terms:	Anti-Bacterial Agents, Azithromycin, Bangladesh, Ceftriaxone, Ciprofloxacin, Colony Count, Microbial, Dose-Response Relationship, Drug, Drug Resistance, Bacterial, Drug Resistance, Multiple, Bacterial, Dysentery, Bacillary, Humans, Microbial Sensitivity Tests, Sentinel Surveillance, Shigella, Species Specificity, Treatment Outcome

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