High rate of resistance to ceftriaxone and azithromycin among Shigella spp. isolates at three children's referral hospitals in Northeast Iran.

Acute dysentery is a prevalent case of hospital admission in developing countries, whose most common cause is believed to be Shigella species. Treatment failure employing oral or intravenous antibiotics is an increasing problem among children with dysentery. This is a prospective descriptive study that aims to find the antibiotic resistance pattern of Shigella spp. isolates from children with acute diarrhea in three children's referral hospitals in Mashhad, northeast-Iran. Between February 2018 to September 2019, a total of 233 stool samples were collected from children with inflammatory diarrhea. Shigella spp. were identified by culture and biochemical standard tests. Moreover, polyvalent Shigella antisera were used for serogrouping. The antibiotic susceptibility was performed by disk diffusion method. During the 9-month study period, a total of 94 non-duplicate clinical Shigella spp. were identified by culture and biochemical tests. Based on slide agglutination with appropriate group-specific polyvalent antisera, Shigella sonnei (70.2%) was found to be the most prevalent Shigella spp. followed by S. flexeneri (23.4%), S. dysentery (1%). Among isolates, S. boydii was not detected and five isolates (5.3%) were nonserotypable isolates. The resistance rate of Shigella spp. to azithromycin, ceftriaxone, ciprofloxacin, co-trimoxazole, nalidixic acid, gentamicin, amoxicillin, ampicillin, doxycycline and cefixime was 25.5%, 43.6%, 3.8%, 82.9%, 15.9%, 26.6%, 40.4%, 57.4%, 41.4%, 22.3%, respectively. The results revealed that the resistance of Shigella spp. to the three most commonly utilized antibiotics (azithromycin, ceftriaxone and, cefixime) is too high to recommend them as empirical therapy for children with acute dysentery in this city.