Comparison of the prevalence and changing resistance to nalidixic acid and ciprofloxacin of Shigella between Europe-America and Asia-Africa from 1998 to 2009

Shigella is becoming an increasing public health problem due to development of multiple antimicrobial resistance, frequently resulting in treatment failure. A systematic review was conducted based on a literature search of computerised databases. Random or fixed-effects models were used, based on the P-value considering the possibility of heterogeneity between studies, for meta-analysis. Statistical analyses were performed using STATA 10.0. In the area of Asia-Africa, resistance rates to nalidixic acid and ciprofloxacin were 33.6% [95% confidence interval (CI) 21.8-46.6%] and 5.0% (95% CI 2.8-7.8%), respectively, 10.5 and 16.7 times those of Europe-America. Moreover, resistance to nalidixic acid and ciprofloxacin in Asia-Africa progressively increased each year, reaching 64.5% (95% CI 13.8-99.3%) and 29.1% (95% CI 0.9-74.8%), respectively, in 2007-2009, whilst isolates in Europe-America remained at low levels of resistance (<5.0% and <1.0%, respectively). All Shigella flexneri strains showed higher resistance than Shigella sonnei in Europe-America: overall, 3.5% (95% CI 1.4-6.4%) vs. 2.6% (95% CI 1.0-5.0%) resistant to nalidixic acid and 1.0% (95% CI 0.3-2.2%) vs. 0.1% (95% CI 0.0-0.3%) resistant to ciprofloxacin. In Asia-Africa, a similar trend was found for ciprofloxacin [3.0% (95% CI 1.4-5.3%) vs. 0.5% (95% CI 0.2-0.8%)], whereas the trend was reversed for nalidixic acid [32.6% (95% CI 14.5-53.9%) vs. 44.3% (95% CI 26.9-62.5%). In conclusion, quinolone resistance in Shigella has increased at an alarming speed, reinforcing the importance of continuous monitoring of antimicrobial resistance in Shigella. (C) 2012 Elsevier B. V. and the International Society of Chemotherapy. All rights reserved.