Trends in antimicrobial resistance of Shigella species in Peru, 2011-2020.

Objective: To describe the frequency of antimicrobial resistance rates and spatial-temporal distribution of Shigella species from the last 10 years in Peru. Methods: A cross-sectional descriptive study was carried out. A total of 1668 Shigella strains, remitted as part of the national enteric pathogen surveillance from 2011 to 2020, were analysed. The strains were confirmed by conventional tests and serotyped with polyvalent and monovalent antibodies. Also, antimicrobial susceptibility was performed according to the Kirby-Bauer method. Results: The most frequent Shigella species was S. sonnei (49.2%), followed by S. flexneri (42.2%), S. boydii (7.9%) and S. dysenteriae (0.7%). Phase II (46.29%) was the most frequent serotype in S. sonnei, serotype 2a (43.61%) in S. flexneri, serotype 2 in S. boydii and serotype 4 in S. dysenteriae. High rates of resistance were detected for trimethoprim/sulfamethoxazole (91.0%), tetracycline (88.4%), ampicillin (73.9%) and chloramphenicol (64.9%), moderate rates for amoxicillin/clavulanic acid (25.1%), ciprofloxacin (16.7%) and nalidixic acid (14.8%), and low rates for cefotaxime (1.74%), nitrofurantoin (0.7%) and ceftazidime (0.6%). Moreover, antimicrobial resistance to fluoroquinolones increased considerably from 2017 to 2020. Conclusion: S. sonnei was the most frequent species, which have a large proportion of strains resistant to trimethoprim/sulfamethoxazole, and a growing trend of resistance to ciprofloxacin and nalidixic acid. This increase in resistance to commonly used antibiotics in treatments is alarming, threatening the control and management of these currently treatable infections.