Magnitude of drug resistant Shigellosis: a report from Bangalore.

Shigella is an important cause of acute invasive diarrhea in children and others. Antimicrobial susceptibility of Shigella spp. isolated from diarrhoeal/ dysenteric patients in Bangalore was studied in our hospital from January 2002 to December 2007. One hundred and thirty-four isolates were identified as Shigella species. S. flexneri, S. sonnei , S. boydii and S. dysenteriae were accounted respectively for 64.9%, 21.6%, 8.2% and 3.7% of the total number of Shigella isolated. Of these 56 (41.8%) were from children (0 to 14 years) and 78 (58.2%) were from adults and elderly patients. Over 70% of Shigella isolates were resistant to two or more drugs including Ampicillin and Co-trimoxazole. During 2002 to 2007, resistance to Ampicillin had increased from 46.7% to 68%. For Co-trimoxazole, though the resistance had gradually decreased from 100% to 72%, but still the resistance is high. Chloramphenicol resistance showed sudden decline from 73.3% to 25% from 2002 to 2003, but gradually has reached 48%. Nalidixic acid resistance was more than 70%. All isolates were sensitive to Ciprofloxacin during the period 2002 to 2004, but over the years the resistance pattern gradually increased up to 48%. Ceftriaxone had shown no resistance. The results of the study revealed the endemicity of Shigellosis with S. flexneri as the predominant serogroup. Children were at a higher risk of severe shigellosis. The results also suggest that Ampicillin, Co-trimoxazole, Chloramphenicol, Nalidixic acid and Ciprofloxacin should not be used empirically as the first line drugs in the treatment of Shigellosis. Periodic analysis and reporting of antibiotic susceptibility is an important measure to guide antibiotic treatment.